MSK Flashcards

Question

Oesteomyelitis Most common pathogens in: * new born * children * adults * drug addicts * Sickle cell * Diabetics 2019 Aug Q98

Answer 1

OSTEOMYELITIS Dahnert = infection of bone caused by bacteria, fungi , parasites, viruses * Acute Osteomyelitis * Age: most commonly affects children * Organism: * (a) **newborns**: * S. aureus, * group B streptococcus, * Escherichia coli * (b) **children**: * S. aureus (blood cultures in 50% positive) * (c) **adults**: * S. aureus (60%), * enteric species (29%), * Streptococcus (8%) * (d) **drug addicts:** * Pseudomonas (86%), * Klebsiella, * Enterobacteriae; (57 days average delay in diagnosis) * (e) **sickle cell disease:** * S. aureus, * Salmonella * (f) **diabetics**: * often multiple organisms like S. aureus, * Streptococcus, E. coli, Klebsiella, Clostridia, * Pseudomonas (in soil+ sole of shoes) Cause: * (1) genitourinary tract infection (72%) * (2) lung infection (14%) * (3) dermal infection (14%): direct contamination from a soft-tissue lesion in diabetic patient Pathogenesis : * (a) hematogenous spread * (b) direct implantation from a traumatic/iatrogenic source * (c) extension from adjacent soft-tissue infection It has been reported that the most frequently isolated organism in neonates with osteomyelitis is **S aureus, which is responsible for up to 70% to 90% of the cases.**[8,16] Other microorganisms, including Streptococcus agalactiae, E coli, Klebsiella, and Candida albicans, are recognized as potential pathogens. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6336599/#:~:text=It%20has%20been%20reported%20that,to%2090%25%20of%20the%20cases.&text=Other%20microorganisms%2C%20including%20Streptococcus%20agalactiae,are%20recognized%20as%20potential%20pathogens.

Answer 2

Guyon's Cannal Syndrome: * rare * compression injury of Ulnar nerve by a space-occupying lesion in cannal Other Causes: * extrinsic compression (cyclist's arm) * thrombosis/aneurysm of superficial palmar branch of ulnar artery * "hypotremar HAMMAR SYNDROME"

Answer 3

* Figure 8(A, B) * (A) Longitudinal view of supraspinatus tendon (SSP). Full-thickness tear of the tendon (long arrow) that reaches from the bursal to the articular margin with sagging of the overlying bursa (short arrow). (B) Long-axis view of the right SSP. Partial thickness articular surface tear (black arrow) and a bright anterior aspect of humeral cartilage (white arrow) – Cartilage interface sign * https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3698891/

Answer 4

* Cortical Desmoid * posteriomedial distal femur * medial gastroc/adductor mag * Pseudotumour of the humerus from the greater tuberosity * Deltoid Tuberosity

Answer 5

Pure valgus stress footy tackle/labradoor dog. COntusion laterally, tear medially

Answer 6

LOOSER ZONES Looser zones Dr Patrick Rock◉ and Assoc Prof Frank Gaillard◉◈ et al. Looser zones, also known as cortical infractions, Milkman lines or pseudofractures, are wide, transverse lucencies with sclerotic borders traversing partway through a bone, usually perpendicular to the involved cortex, and are associated most frequently with osteomalacia and rickets. Given that these lesions are a type of insufficiency fracture, they are not themselves diagnostic of osteomalacia. Osteomalacia is the strongly favoured diagnosis when these are bilaterally symmetric and in a classic location such as the axillary border of the scapulae, ribs, or posterior ulnae. Other frequently involved sites include the superior and inferior pubic rami, and proximal medial femora. True fractures may occur through these weakened sites.4 Terminology The term pseudofracture is a misnomer, as they are considered a type of insufficiency fracture. Typically, the fractures have sclerotic irregular margins and are often symmetrical. Pathology Looser zones contain regions of demineralised osteoid, frequently with superimposed osteitis fibrosa cystica due to the presence of hyperparathyroidism. Aetiology osteomalacia renal osteodystrophy fibrous dysplasia hyperthyroidism Paget disease of bone X-linked hypophosphataemia osteogenesis imperfecta hypophosphatasia Location Looser zones occur in the same locations as insufficiency fractures in weight-bearing bones: pubic rami medial femoral neck medial proximal femoral shaft (c.f. bisphosphonate-related fractures that occur on the lateral cortex of the proximal femoral shaft) In non-wieghting-bearing bones, they often occur along nutrient foramina and represent true pseudofractures: lateral scapula posterior proximal ulna ribs iliac wing History and etymology Looser zones are named after Emil Looser, a Swiss surgeon, working in Zurich (1877-1936) 3. Louis Arthur Milkman (1895-1951) was an American radiologist who described the findings in seminal papers in 1930 and 1934 2,3.

Answer 7

Ewing sarcoma There is a lesion located in the distal femur with typical aggressive features of a malignant tumour with: irregular and partial destruction of cortical bone periosteal reaction with Codman triangle formation indistinct zone of transition perpendicular spiculations producing a sunburst appearance associated large soft tissue swelling Histologically proven Ewing sarcoma. Green: Cortical bone destruction Pink: Periosteal reaction Arrow: Codman triangle Blue: Sunburst appearance Yellow lines: Cortical thinning Gray lines: soft tissue expansion Case Discussion Pathologically proven Ewing sarcoma. This is a highly malignant bone tumour seen in the first two decades of life. The main differential diagnosis is osteosarcoma. References Dr Subhan Iqbal◉ and Assoc Prof Frank Gaillard◉◈ et al. Ewing sarcomas are the second most common malignant primary bone tumours of childhood after osteosarcoma, typically arising from the medullary cavity with the invasion of the Haversian system. They usually present as moth-eaten destructive permeative lucent lesions in the shaft of long bones with large soft tissue component without osteoid matrix and typical onion skin periostitis. It may also involve flat bones and appears sclerotic in up to 30% of cases. E**pidemiology** **Ewing sarcoma typically occurs in children and adolescents between 10 and 20 years of age** (95% between 4 and 25 years of age) and has a slight male predilection (M: F 1.5:1) 1,2. The Ewing sarcoma family of tumours primarily occurs in white patients. In the United States, the incidence in Asians/Pacific Islanders is about one-half that in Caucasians, while the incidence among African Americans is one-ninth that in Caucasians 12. Clinical presentation Presentation is non-specific with local pain being by far the most common symptom. Occasionally a soft tissue mass may be palpable. Pathological fractures also occur. Systemic symptoms including fever may be present. ESR and serum LDH levels are also elevated 14. Pathology Ewing sarcoma is a **small round blue cell tumour** with regular-sized primitive appearing cells. **It is closely related to the soft tissue tumours pPNET,** Askin tumour and neuroepithelioma, which collectively are referred to as Ewing sarcoma family of tumours (ESFT) 1. They share not only microscopic appearances but also demonstrate a non-random t(11;22)(q24;q12) chromosome rearrangement. **Location** **lower limb: 45%** **femur most common** pelvis: 20% upper limb: 13% spine and ribs: 13% (see thoracic Ewings sarcoma) the sacrococcygeal region most common 4 skull/face: 2% Alternatively 3: long bones: 50-60% femur: 25% tibia: 11% humerus: 10% flat bones: 40% pelvis: 14% scapula ribs: 6% (thoracic Ewing sarcoma) **As far as a location within long bones, the tumour is almost always metadiaphyseal or diaphyseal 2-3:** **mid-diaphysis: 33%** **metadiaphysis: 44%** metaphysis: 15% epiphysis: 1-2% Radiographic features **Ewing sarcomas tend to be large with poorly marginated tumours, with over 80% demonstrating extension into adjacent soft tissues. It should be noted that pPNET often extend into bone, making the distinction difficult.** Plain radiograph and CT The appearance of these tumours is very variable, but they usually have clearly aggressive appearance. Common findings include 2,14: **permeative: 76%** **lamellated (onion skin) periosteal reaction: 57%** **sclerosis: 40%** They occasionally demonstrate other appearances, including Codman triangles, spiculated (sunburst) or thick periosteal reaction and even bone expansion or cystic components. Soft tissue calcification is uncommon, seen in less than 10% of cases 2. MRI T1: low to intermediate signal T1 C+ (Gd): heterogeneous but prominent enhancement T2: heterogeneously high signal, may see hair on end low signal striations Nuclear medicine Ewing sarcomas demonstrate increased uptake on both Gallium67-citrate and all three phases of the Technetium99m methylene diphosphonate bone scans 6. Treatment and prognosis Systemic chemotherapy is the mainstay of treatment with surgery and/or radiotherapy playing a role depending on the location and size of the tumour. What was once a uniformly fatal tumour now has respectable survival rates, although these vary with location. Spinal tumours for example have up to 86% long term survival compared to 25% of sacrococcygeal tumours 4. The overall 5 year survival is in the order of 50-75% of patients with local disease only at the time of presentation 5. Prognosis is significantly impacted by the presence of distant metastases at the time of diagnosis, which is far more common for the pelvis (25-30%) compared to extremities (\<10%) 5. Metastases most frequently go to lungs and bones in equal proportions. The spine is the most commonly affected bone 13. History and etymology It is named after James Stephen Ewing (1866-1943), an American pathologist, who first described his eponymous tumour in 1920 8,11. **Differential diagnosis** **other Ewing sarcoma family of tumours** **pPNET: large soft tissue component with extension into bone** **Askin tumour: chest wall** osteosarcoma: more often has amorphous calcified matrix classically perimetaphyseal, Ewing sarcoma also occurs in other locations more prevalent around the knee and in the proximal humerus, in other locations Ewing sarcoma is the more frequent of the two osteomyelitis metastatic disease haematological malignancy eosinophilic granuloma 9 neuroblastoma (

Answer 8

* horiszontal * involve an artcular surface and propogate to the periphery * a/w parameniscal cysts * usually degen. No hx of trauma * older patient * rx = debridment. * oblique * verticle/longitudinal tear * Most common in the ACL tears * Posterior horn of Lat or medial mesicus * Wrisberg rip tear * vert and long tear * PH LM * Lig of Wrisber attaches from the inner aspect of the MCF * Ramp lesion * vert long tear, can propgogate and turn into a bucket handle tear into the intercondylar notch * can cause locking * best tears to rx with surgery. * longituidine * radial * Ghost sign: mesniscus fades out on a slice * Flap tear * Meniscal root tear Tears on the inner edge wont heal. they can propogate.

Answer 9

ddx for FD = OM THis is OM Thick periosteal reaction.

Answer 10

Peripheral primitive neuroectodermal tumour pPNET in a 21-year-old man. Precontrast CT images showed a lobular iso-dense mass with necrosis in the left retroperitoneum (A) . Enhanced CT images showed the mass had heterogeneous contrast uptake (B-C) . Precontrast MRI showed the mass had an ill-defined border that was iso-intense on T1WI (D) and hyper-intense on T2WI (E) . Contrast MRI showed the mass had significant and heterogeneous enhancement (F) . Sagittal enhanced MRI images showed the mass invaded the 5th lumbar vertebrae and spinal canal (G) . The small round tumor cells were positive for CD-99 (H × 100). https://www.researchgate.net/figure/pPNET-in-a-21-year-old-man-Precontrast-CT-images-showed-a-lobular-iso-dense-mass-with\_fig2\_270706146 Dr Daniel J Bell◉ and Dr Jeremy Jones◉ et al. Peripheral primitive neuroectodermal tumours (pPNET) tend to be large and aggressive retroperitoneal tumours. Radiographic features The imaging characteristics of peripheral PNETs are non-specific. However, they should be considered in the differential diagnosis of a large, aggressive retroperitoneal mass. See also Ewing sarcoma family of tumours small round blue cell tumours

Answer 11

Shoulder (outlet view) Jessica Hui Shi Ng◉ and Andrew Murphy◉ et al. The outlet or Neers projection of the shoulder is a specialised projection demonstrating the coracoacromial arch often utilised in the investigation of shoulder impingement 1. This projection is most commonly seen in orthopaedic clinics and closely resembles a lateral scapular projection but incorporates a 10-15 degree caudal angulation of the tube. The outlet projection is not advisable in acute imaging of the shoulder as tube angulation may result in elongation of decisive structures. For lateral views of the shoulder in trauma see lateral shoulder view. Indication The outlet view is performed to assess subacromial impingement. This view is often performed instead of a lateral shoulder view for the impingement series only. Patient position erect or sitting, facing the upright detector rotated in an anterior oblique position, so the anterior portion of the shoulder is touching the upright detector the hand is placed on the patient's abdomen with the arm flexed the degree of anterior rotation can vary from patient to patient scapula should be end-on to the upright detector, and this can be done via palpation of the scapula border Technical factors posteroanterior lateral projection centring point the level of the glenohumeral joint on the posterior aspect of the patient (5 cm below the top of the shoulder) 10-15 degree caudal angulation of the x-ray tube central to the medial scapula border collimation laterally to include the skin margin medially to cover the entirety of the medial scapula superior to the skin margin inferior to the inferior angle of the scapula orientation portrait detector size 24 x 30 cm exposure 60-70 kVp 10-20 mAs SID 100 cm grid yes Image technical evaluation the scapula is demonstrated in a lateral profile, giving the clear appearance of a ‘Y' clear visualisation of the supraspinatus outlet acromion and the coracoid process form the upper arms of the ‘Y' if intact, the humeral head is superimposed at the base of the ‘Y' Practical points The lateral scapula projection can be technically demanding, especially when patients are in pain. An anecdotal method amongst radiographers is to feel for the medial border of the scapula and line it up with the anterior portion of the acromion and x-ray straight down the line. The idea being, if they are lined up there will be a superimposition of the medial and lateral borders of the scapula and hence a perfect lateral position, although this is not always the case. The best defence against positional errors is having a thorough understanding of radiographic anatomy and how it changes positionally when assessing for under/over rotation of the lateral shoulder, evaluate the borders of the scapula. Over rotation Over rotation in this projection refers to the patient's unaffected side sitting too far away from the image receptor, otherwise known as lying ‘too square’ to the detector. Over-rotation is clearly established as the lateral border of the scapular (significantly thicker than the medial) is projected over the thorax along with the humeral head; to adjust this, rotated the unaffected side towards the image receptor slightly. Under rotation Under rotation in this projection refers to the patient's unaffected side sitting too close to the image receptor, otherwise known as lying ‘flat’ to the detector. The lateral border, as well as the humeral head, will be sitting overly lateral in the image; to fix this, rotated the unaffected side away from the detector to increase obliquity. References

Answer 12

HOGWASH * H: hyperparathyroidism, hypothyroidism, haemophilia * O: ochronosis * G: gout * W: Wilson disease * A: arthritis (rheumatoid, postinfectious, traumatic, degenerative), amyloidosis, acromegaly * S: pseudogout * H: haemochromatosis

Answer 13

* Fracture of the MCP neck * Most commonly the 5th MCP * with volar angulation and external rotation of the distal fragment * simple #s are reduced externally * Votar comminution usually requires ORIF

Answer 14

Sclerosing osteomyelitis of Garré Dr Bahman Rasuli and Dr Yuranga Weerakkody◉ et al. Sclerosing osteomyelitis of Garré is a specific type of chronic osteomyelitis. It mainly affects children and young adults. It typically affects the mandible and is commonly associated with an odontogenic infection resulting from dental caries. Radiographic features Orthopantomogram (OPG) A localised overgrowth of bone on the outer surface of the cortex. This mass of bone, which is supracortical but subperiosteal, is smooth, fairly calcified, and is often described as a duplication of the cortical layer of the mandible. The redundant cortical layering of the bone (onion skinning) is often considered a pathognomonic feature 8. History and etymology It was first described by Carl Garre in 1893 6.

Answer 15

**Semimanbranous bursitis** dont mix up with a bakers cyst or a parameniscal cyst has a **classic comma shape.**

Answer 16

Gout * crystal arthropathy * deposition of monosodium urate crystals in and around the joints. * Epidemiology * above 40 years * strong male predilection of 20:1, with this predilection more pronounced in younger and middle-aged adults. In the elderly, the gender distribution is more equal * Clinical presentation * monoarticular red, inflamed, swollen joint, typically in the lower limb and classically affecting the first metatarsophalangeal joint (podagra) * during sleep, and can later involve more than one joint to become an oligoarthropathy or rarely, a polyarthropathy 12. * At 7-10 days, there is an intercritical asymptomatic period (intercritical gout) between acute flares. * Patients with chronic uncontrolled hyperuricaemia, such as those with chronic kidney disease, may develop chronic tophaceous gout. In chronic tophaceous gout, there are solid urate crystal collections (tophi) and chronic inflammatory and destructive changes in surrounding connective tissue * These tophi are typically yellow-white in colour, non-tender, and are typically located within the articular structures, bursae, or the ears * Pathology * monosodium urate crystals deposition in periarticular soft tissues. * The crystals are needle-shaped * strongly birefringent in plane-polarised light * The synovial fluid is generally a poor solvent for monosodium urate and therefore crystallisation occurs at low temperatures. * The crystals are chemotactic and activate complement. * There are five recognised stages of gout: 1. asymptomatic hyperuricaemia 2. acute gouty arthritis 3. intercritical gout (between acute attacks) 4. chronic tophaceous gout 5. gouty nephropathy * Risk factors * hyperuricaemia * undersecretion of uric acid by the kidneys (most common) or * chronic kidney disease * hypertension * hyperparathyroidism * Etoh * Drugs * furosemide * thiazide diuretics * ethambutol * purazinamide * aspirin * lead poinsonig * obesity * overproduction of uric acid (only 10% of cases). * Myeloproliferative disorders * hemolysis * extreme exercise * Lesch-Nyhan Syndrome

Answer 17

soap bubbly intertrochanteric Fibrous dysplasia

Answer 18

Prepatellar bursitis Dr Magdalena Chmiel-Nowak◉ and Dr Ahmed Abdrabou et al. Prepatellar bursitis is inflammation and fluid collection within the prepatellar bursa, located between the patella and the overlying subcutaneous tissue. It has been historically referred to as "housemaid's knee". Clinical presentation Main symptoms are anterior knee pain and swelling. Pathology Chronic irritation due to trauma or repetitive kneeling lead to accumulation of fluid within the prepatellar bursa and sometimes haemorrhagic transformation. Less common causes include: rheumatoid arthritis gout infection Radiographic features Plain radiograph May show prepatellar soft tissue swelling clumps of calcifications in the prepatellar soft tissues in chronic cases 3 Ultrasound Hypoechoic fluid, sometimes containing debris, is noted anteriorly to the patellar surface 2. MRI Oval shaped fluid-filled sac is seen anterior to the patella and displays low T1 and bright T2/STIR signal intensity. When haemorrhage occurs T1 signal increases and T2 GRE signal reduces. The wall of the bursa may show increased thickness and irregularity. Treatment and prognosis Local injection of non-steroid anti-inflammatory drugs and steroids or local application of ice, and finally bursectomy in resistant cases.

Answer 19

Patellar sleeve fracture Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al. Patellar sleeve fractures (also commonly, patellar sleeve avulsion fracture) represent chondral or osteochondral avulsion injury commonly at the inferior pole of the patella (including cartilage from the articular surface, as well as periosteum and cartilage over the dorsal surface). Very rarely it can involve the upper pole 5. This is an important diagnosis as the displaced bone-forming tissue will continue to grow and ossify, enlarging, and possibly duplicating the patella. Epidemiology Patellar sleeve fractures occur in the paediatric population between 8 and 16 years of age, with a peak incidence at 12.7 years, predominantly boys (3:1). Adolescents are more susceptible due to rapid growth, increased sports activity, and relative patella instability. Clinical presentation Unlike Sinding-Larsen-Johansson disease, these injuries are acute and result from sudden and forceful contraction of quadriceps muscle (indirect mechanism). Acute focal pain and tenderness occur at the time of the injury, and a palpable gap may be present. Radiographic features Plain radiograph Lateral knee x-rays demonstrate swelling at the lower pole of the patella and some degree of patella alta. If a small bony fragment has been avulsed with the cartilage, then this too may be seen. A joint effusion may not be present. Ultrasound Ultrasound may be helpful in the absence of a radiographically visible fracture fragment. A disruption of the cartilage may be seen, and the degree of separation estimated. Ancillary findings of soft-tissue oedema, fluid, and hyperaemia may be helpful. MRI MRI is critical if the diagnosis is suspected as the degree of chondral injury cannot be assessed on plain radiography, and coexistent extensor mechanism injury may be present. Treatment and prognosis Surgical treatment is recommended when there is significant displacement (\>2 mm) of the displaced osteo/chondral fragment. Differential diagnosis Sinding-Larsen-Johansson disease: chronic jumper's knee: chronic and seen in adults Osgood-Schlatter disease: chronic and affects the inferior attachment of the patellar tendon patella fracture quadriceps tendon rupture

Answer 20

**Primary synovial chondromatosis** * benign monoarticular disorder * unknown origin * synovial metaplasia and proliferation * multiple intra-articular cartilaginous loose bodies of relatively similar size * not all of which are ossified. * Hence, the term synovial chondromatosis is preferred over primary synovial osteochondromatosis. * It is distinct from secondary synovial chondromatosis that is the result of a degenerative change in the joint. Epidemiology * 4th or 5th decades of life 2. * Men are affected more frequently (M:F ratio of 2:1 to 4:1) Clinical presentation * pain, swelling, and limitation of motion, which often progresses slowly for several years. * Joint effusions * restricted range of motion. Pathology * Primary synovial chondromatosis is a self-limiting benign neoplastic process * proliferative chondroid nodules of the synovium. Three phases of articular disease have been identified: 1. **initial phase:** metaplastic formation of cartilaginous nodules in the synovium 2. **transitional phase:** detachment of those nodules and formation of free intra-articular bodies 3. **inactive phase:** resolution of synovial proliferation, but loose bodies remain in the joint, and may increase in size obtaining nourishment from the joint fluid by diffusion Location * Usually, the condition is monoarticular affecting any joint but the large joints are preferentially affected: * knee (up to 70%) 4 * hip (20%) * elbow * shoulder * Occasionally, bursa or tendon sheaths may be involved 1,2.

Answer 21

Subchondral insufficiency fracture Dr Yuranga Weerakkody◉ et al. Subchondral insufficiency fracture refers to a type of stress fracture that occurs below the chondral surface on a weight-bearing surface of a bone due to mechanic failure of subchondral cancellous bone. Pathology They tend to occur when normal physiological forces are repeatedly applied to an area of bone. Callus formation occurs along with non-mineralised osteoid and the absence of bone infarction. Risk factors osteoporosis obesity abnormal loading through the joint overuse Location Typical sites include: knee: can progress to spontaneous osteonecrosis of the knee 5 femoral head femoral condyles tibial plateau metatarsal head Complications secondary osteonecrosis osteonecrosis with cavitation (crescent sign) articular collapse destructive arthropathy Radiographic features Plain radiography and CT Radiographs are normal preceding the development of callus formation or collapse of the articular surface. Linear or patchy subchondral sclerosis may be present representing cancellous fracture. MRI T1: may be characteristically low signal intensity band through the affected region parallels the subchondral bone plate whereas osteonecrosis is curvilinear preservation of the articular cartilage whereas an osteochondral defect is involved T2: florid marrow oedema History and etymology It is described in many regions but the the term subchondral insufficiency fracture of "femoral head" was coined by Bangil et al in 1996 7 Differential diagnosis The differential diagnosis of subchondral marrow oedema includes: osteoarthritis stress response marrow contusion transient osteoporosis See also insufficiency fracture subchondral fracture case Tear of the posterior root medial meniscus with extrusion of the meniscal body. Upper surface horizontal tear of the body lateral meniscus extending to the undersurface of the posterior horn with posterolateral parameniscal cyst formation. Grade 4 chondral loss on both femoral and tibial surface medial compartment. Oedema throughout the medial femoral condyle centred on a 10 mm subchondral T1 hypointensity with some cortical depression of the weight-bearing surface. Case Discussion Subchondral insufficiency fractures, previously known as spontaneous osteonecrosis of the knee (SONK), are often very painful. In this case, there are associated severe meniscal injuries.

Answer 22

The anteater nose sign refers to an anterior tubular elongation of the superior calcaneus which approaches or overlaps the navicular on a lateral radiograph of the foot. This fancifully resembles the nose of an anteater and is indicative of calcaneonavicular coalition 1,2.

Answer 23

Calcium Pyrophosphate Crystal Deposition Disease AKA (Pseudogout) (p. 1217) Robins Calcium pyrophosphate crystal deposition (CPPD) disease typically occurs after age 50, with a 30% to 60% prevalence by age 85; the hereditary variant presents somewhat earlier and the phenotype is more severe. An autosomal dominant form of the disease is due to mutations in the ANKH gene encoding a pyrophosphate transport channel. The most common secondary form is associated with a variety of etiologies, including trauma, hyperparathyroidism, hemochromatosis, and diabetes; altered matrix synthesis and degradation of pyrophosphates are implicated. The clinicopathologic features are similar to gout. The crystals initially form in cartilage; as deposits enlarge they rupture and seed the joint where macrophages engulf them and activate their inflammasomes to generate IL-1β. Subsequent neutrophil recruitment and recurrent bouts of inflammation result in joint damage in more than 50% of patients. Knees, wrists, elbows, shoulders, and ankles are affected (in decreasing order). Morphology (p. 1217) • Gross: Crystals form chalky white, friable deposits; they rarely deposit in large masses. • Microscopic: **Crystals stain as oval, blue-purple aggregates; they are weakly birefringent and have geometric shapes. Chronic lesions exhibit mononuclear cell infiltrates with fibrosis.** Dahnert **Calcium pyrophosphate dihydrate crystal deposition disease = CPPD Target areas: MCP (2nd, 3rd), radiocarpal; bilateral symmetric I asymmetric changes './ chondrocalcinosis +periarticular calcifications: './ calcification of triangular fibrocartilage** **\>I "degenerative changes" in unusual locations: \>I narrowing ±obliteration of space between distal radius and scaphoid ± fragmentation of surfaces \>I scapholunate separation \>I destruction of trapezioscaphoid space \>I no erosions \>I + large osteophytes = hemochromatosis**

Answer 24

Osteochondritis dissecans Dr Mostafa El-Feky◉ and Assoc Prof Frank Gaillard◉◈ et al. Osteochondritis dissecans (OCD) is the end result of the aseptic separation of an osteochondral fragment with the gradual fragmentation of the articular surface and results in an osteochondral defect. It is often associated with intraarticular loose bodies. Epidemiology Onset is between childhood and young adults age, with the majority of patients being between 10 and 40 years of age, with approximately a 2:1 male to female ratio 3. Risk factors repetitive throwing / valgus stress and gymnastics / weight bearing on upper extremity valgus stress / compressive force on the vulnerable chondroepiphysis of the radiocapitellar joint in skeletally immature patients is supported as the aetiology for OCD of the capitellum 8 ankle sprain/instability In the talus, 96% of lateral lesions and 62% of medial lesions were associated with direct trauma 9 competitive athletics 10 family history: epiphyseal dysplasia has been postulated as a subset of OCD 11 Clinical presentation Symptoms are variable and range from asymptomatic to significant pain and locking (suggesting loose body formation). Joint effusions and synovitis are often present. Pathology The exact aetiology is uncertain and controversial, with the majority of cases thought to be the result of trauma 4. In up to 40% of cases, patients give a history of trauma as the inciting event 3. Other postulated causes include 4: avascular necrosis (AVN) fat emboli microtrauma familial dysplasia Location Many joints can be affected, but typical locations include: femoral condyles are most common site accounting for ~95% of all cases: osteochondritis dissecans of the knee talus: osteochondritis dissecans of the ankle capitellum: osteochondritis dissecans of the elbow glenoid 7 Staging See osteochondral injury staging and osteochondritis dissecans surgical staging. Radiographic features Plain radiograph Plain radiographs should be the first step in the evaluation of knee pain, however, unless advanced changes are present and/or a meticulous technique employed, early findings of osteochondritis dissecans may be occult. The intercondylar "notch" view is very helpful. Early findings include subtle flattening or indistinct radiolucency about the cortical surface. As the process progresses, more pronounced contour abnormalities, fragmentation and density changes (both lucency and sclerosis) become evident. If an osteochondral fragment becomes unstable and displaced, then donor site and intra-articular fragment may be seen. CT CT has the advantage of sectional imaging through the joint and multiplanar reformats. Findings are similar to those seen on plain radiographs. MRI MRI is the modality of choice, with high sensitivity (92%) and specificity (90%) 4 in the detection of separation of the osteochondral fragment. This is essential in determining management. T1: variable signal overall with intermediate to low signal adjacent to fragment and variable fragment signal T2: the high signal line demarcating fragment from bone usually indicates an unstable lesion however false positives can result from oedema 6 low signal loose bodies, outlined by high signal fluid donor defect filled with high signal fluid high signal subchondral cysts T1+gad: enhancement indicates the viability of the lesion The four classic signs of instability described at MRI include 14 : high signal intensity rim at the interface between the fragment and the adjacent bone on T2-weighted MR image fluid-filled cysts beneath the lesion high signal intensity line extending through the articular cartilage overlying the lesion focal osteochondral defect filled with joint fluid, indicating complete detachment of the fragment Complications persistent pain with activity: ~ 2/3 following surgical management of knee and 40% following surgical management of elbow 12,13 articular incongruity 13 early degenerative joint disease 13 Treatment and prognosis Spontaneous healing is usual unless there is an unstable fragment, and treatment revolves around rest and immobilisation for up to a year 5. When the fragment is unstable or displaced, without treatment patients are susceptible to premature secondary osteoarthritis. Numerous surgical approaches have been tried, including drilling, bone grafting, replacement of bone fragment and pinning 5. When surgery is performed, the results in most cases are only "fair". ~50% (range 35-70%) of patients achieve a "good to excellent" clinical outcome 3 but even in these cases, the majority develop osteoarthritis. History and etymology It was first described by the German surgeon Franz Konig in 1888. Differential diagnosis normal irregular distal femoral epiphyseal ossification avascular necrosis osteochondral impaction fracture stress/insufficiency fracture See also differential diagnosis of erosive arthritis Osteochondritis dissecans (surgical staging) Dr Jeremy Jones◉ and Assoc Prof Frank Gaillard◉◈ et al. Osteochondritis dissecans can be classified at surgery into 4 stages: stage I stable lesion in continuity with the host bone covered by intact cartilage stage II stable on probing partial discontinuity of the lesion from the host bone stage III unstable on probing fragment not dislocated complete discontinuity of the "dead in situ" lesion stage IV dislocated fragment Classification according to International Cartilage Repair Society. Of course distinguishing stage II from III can be difficult on MRI.

Answer 25

https://radiopaedia.org/articles/elastofibroma-dorsi?lang=gb Elastofibroma Dorsi Bilateral

Answer 26

Patterns of bone bruise in knee injury Dr Daniel J Bell◉ and Dr Henry Knipe◉◈ et al. The pattern of bone bruise in knee injuries (a.k.a. bone contusion) can give clues for the mechanism and associated injuries. Radiographic features Five classic bone contusion patterns have been described 1-4: pivot-shift injury valgus stress to flexed and externally rotated knee contusion pattern: posterolateral tibial plateau and mid part of lateral femoral condyle associated with anterior cruciate ligament (ACL) tears see also: contrecoup injury of the knee, O'Donoghue unhappy triad dashboard injury anterior force to tibia in a flexed knee (e.g. knees against dashboard in motor vehicle collision, or fall onto flexed knee) contusion pattern: anterior tibia +/- posterior patella associated with posterior cruciate ligament (PCL) tear clip injury valgus stress to flexed knee contusion pattern: lateral femoral condyle and lateral tibial plateau +/- medial femoral condyle from medial collateral ligament (MCL) avulsive stress associated with MCL injuries hyperextension injury direct force to anterior tibia with foot planted contusion pattern: "kissing contusions" of anterior tibial plateau and anterior femoral condyle associated with ACL, PCL, meniscal injuries, and in severe cases knee dislocation lateral patellar dislocation twisting injury to flexed knee anterolateral lateral femoral condyle and inferomedial patella associated with medial patellar retinaculum +/- medial patellofemoral ligament injury +/- medial patellotibial ligament injuries

Answer 27

1. OA 2. erosive OA 1. gull wing 3. Psoriasis 1. pencil in cup 2. periostitis (look at sesamoid) shaggy appearance of the cortex 4. ReArth 5. Gout

Answer 28

Erosive osteoarthritis =inflammatory osteoarthritis Age: predominantly middle-aged I postmenopausal women • acute inflammatory episodes Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric I asymmetric './ central erosions combined with osteophytes = subchondral "gull wing" erosions './ joint space narrowing + sclerosis './ rare ankylosis

Answer 29

luck strike makes fine tabacco is the mnemonic

Answer 30

Anterior tibial translocation sign Dr Joachim Feger◉ and Assoc Prof Frank Gaillard◉◈ et al. The anterior tibial translocation sign or anterior drawer sign (a.k.a. anterior translation of tibia) is seen in cases of complete rupture of the anterior cruciate ligament and refers to anterior translocation (anterior tibial subluxation) of the tibia relative to the femur of \>7 mm 1. It measured on sagittal MRI sequences at the lateral femoral condyle.

Answer 31

* Monosodium vs pyrophosphate crystals * Green for Gout generally

Answer 32

* Posterolateral ligamentous complex * AKA * arcuate ligamentous complex) of the knee is an important stabiliser and consists of a number of structures. * Structures: 1. lateral collateral ligament 2. arcuate ligament 3. popliteofibular ligament 4. posterior third of the lateral capsule 5. fabellofibular ligament (when a fabella is present) 6. tendoaponeurotic unit formed by the popliteus muscle (not always included) 7. biceps femoris tendon (not always included) 8. popliteal meniscal ligament (not always included) 9. lateral gastrocnemius muscle (not always included) * Functional classification * static stabilisers (i.e. posterolateral knee joint capsule) * arcuate ligament * popliteofibular ligament * lateral (fibular) collateral ligament * fabellofibular ligament (when the fabella is present) * dynamic stabilisers * tendoaponeurotic unit formed by the popliteus muscle * biceps femoris tendon * lateral gastrocnemius muscle (not always included) * other structures * popliteal meniscal ligament * posterior horn lateral meniscus * lateral coronary ligament * iliotibial band

Answer 33

Freiberg disease Dr Mohamed Saber and Dr Jeremy Jones◉ et al. Freiberg disease, also known as Freiberg infraction, is osteochondrosis of metatarsal heads. It typically affects the 2nd metatarsal head, although the 3rd and 4th may also be affected. It can be bilateral in up to 10% of cases. Epidemiology It is most common in females aged 10-18 years (male to female ratio of 1:3). Clinical presentation Clinically they present with pain on weight-bearing with swelling and tenderness. Pathology The cause of Freiberg infraction is controversial and is probably multifactorial. A traumatic insult in the form of either acute or repetitive injury and vascular compromise, perhaps due to an elongated 2nd metatarsal, are the most popular theories, and as it is more commonly seen in women, particularly during adolescence, high-heeled shoes have been postulated as a possible causative factor. Histologically, Freiberg infraction is characterised by the collapse of the subchondral bone, osteonecrosis, and cartilaginous fissures 1. Radiographic features Plain radiograph These can be split into early and late features: Early flattening and cystic lesions of the affected metatarsal head widening of the metatarsophalangeal joint Late osteochondral fragments sclerosis and flattening of the bone increased cortical thickening Some publications advocate the use of the Bragard staging classification 10, which requires two views/planes of the forefoot: I - metatarsal head flattening and decreased subchondral bone density II - metatarsal head sclerosis, fragmentation, and deformation, with cortical thickening III - metatarsophalangeal osteoarthrosis with intra-articular loose bodies MRI Early MR imaging findings include low-signal-intensity changes in the metatarsal head on T1-weighted images with increased signal intensity on corresponding T2-weighted and STIR images. With disease progression, flattening of the metatarsal head occurs, and low-signal-intensity changes develop on T2-weighted images as the bone becomes sclerotic. History and etymology Albert H Freiberg (1868-1940), was an American orthopaedic surgeon, who first described his eponymous condition in 1914 8,9,11. Differential diagnosis On imaging consider normal variant: metatarsal head flattening is described in ~10% of the asymptomatic population fracture of metatarsal head or neck including subchondral insufficiency fracture lesser metatarsal head instability (only identified on MRI): due to plantar plate tear See also osteonecrosis

Answer 34

Osteofibrous dysplasia * benign fibro-osseous cortical lesion * occurs almost exclusively in the tibia and fibula. * It is most commonly seen in the mid-diaphysis of the tibia. * Terminology * A commonly used synonym is ossifying fibroma of the long bones. * Epidemiology * most common in younger patients, e.g. ~ 10 years of age * less commonly reported in older patients, up to 63 years of age 3 * slight male predilection (3:2 ratio 3) * Clinical presentation * Most patients present with pain and swelling, and patients may present secondary to a pathological fracture. * Pathology * Osteofibrous dysplasia is considered as a benign, non-neoplastic condition. Some consider it as part of a spectrum of osteofibrous dysplasia-like adamantinoma and adamantinoma. * Microscopic appearance * Histology shows trabecular bone woven within fibrous stroma with osteoblastic rimming and mature lamellar bone. * It is closely related to fibrous dysplasia (fibrous dysplasia is predominantly medullary), but the zonal phenomenon and osteoblastic rimming of bony trabeculae are absent in fibrous dysplasia. * Osteofibrous dysplasia and ossifying fibroma of the jaw have similar histological characteristics, but osteofibrous dysplasia shows cytokeratin-positive cells, whereas ossifying fibroma of the jaw shows psammomatous calcification, which are exclusive features. * Although adamantinoma can contain osteofibrous dysplasia-like components, nests or strands of an epithelioid cell are the differentiating feature between adamantinoma and osteofibrous dysplasia. * Adamantinoma with scarce epithelioid component and mostly composed of osteofibrous dysplasia-like tissue are considered as osteofibrous dysplasia-like adamantinoma. * Radiographic features * Osteofibrous dysplasia is classically a lytic lesion centred in the tibial cortex, often with sclerotic margins. * Because of its similarity to adamantinoma, a much more aggressive pathology, a primary issue is differentiating between the two. * Due to intralesional heterogeneity, needle biopsy may result in diagnostic misclassification, particularly with underestimation of aggressive lesions. Thus, radiologic-pathologic correlation is important with benign or equivocal biopsy results 3. * Osteofibrous dysplasia tends to be: * smaller (mean 6-7 cm versus 10-17 cm for adamantinoma) * with more distinct margins * less likely to involve the medullary cavity * Plain radiograph * Plain radiograph remains the initial and chief investigation. * location: * along long axis: mid-diaphysis, especially anteriorly * along transverse axis: cortical with medullary encroachment * consistency * lucent or ground-glass * lobular-to-bubbly in appearance * margins * narrow zone of transition * sclerosis common * no nidus * no aggressive periosteal reaction * benign-appearing periosteal reaction is non-specific, and can be seen in all lesions along the osteofibrous dysplasia/adamantinoma spectrum 3 * +/- pseudotrabeculation and anterior bowing * MRI * MRI is helpful in evaluation of suspected osteofibrous dysplasia, particularly to evaluate the extent of intramedullary involvement. Complete medullary cavity involvement is more suggestive of adamantinoma. * T1: intermediate signal * T2: intermediate-to-high signal * T1C+: diffuse and intense enhancement. * +/- soft tissue component (non-specific) * can be seen in all lesions along the osteofibrous dysplasia/adamantinoma spectrum 3 * no aggressive cortical destruction * Treatment and prognosis * Surgery is reserved for lesions that are large or demonstrate aggressive behaviour. * They usually have an excellent prognosis and usually, stabilise or spontaneously regress once the child is over 10 years old. * It can be locally destructive and may result in pathological fracture, subsequently pseudarthrosis. * Local recurrences can occur after surgery with some aggressive recurrence, possibly due to components of adamantinoma or possible transformation to adamantinoma. * Differential diagnosis * Consider * ossifying fibroma * adamantinoma * osteofibrous dysplasia-like adamantinoma * intracortical fibrous dysplasia

Answer 35

Discoid meniscus Dr Balint Botz ◉ and Assoc Prof Frank Gaillard◉◈ et al. Discoid menisci are those that have a body that is too wide, usually affecting the lateral meniscus. They are incidentally found in 3-5% of knee MRI examinations. Epidemiology Discoid menisci are congenital, frequently bilateral (up to 50%) and have been reported in twins, although no genetic locus has been identified 2. There is a higher prevalence in Asians without any gender predilection 7. Lateral discoid meniscus is far more common than medial discoid meniscus, with the latter being rare. Clinical presentation Although frequently asymptomatic, discoid menisci are prone to cystic degeneration with subsequent tear. Clinical presentation may, therefore, be either incidental or with pain, locking or a 'clunk'. Pathology Discoid menisci have decreased collagen fibres and loss of normal collagen orientation, which predisposes them to intrameniscal mucoid degeneration 7. Classification Classification is based on the degree of peripheral attachments to the tibial plateau, and the shape of the meniscus itself: complete vs incomplete 80% coverage of the tibial plateau is often used as the cut-off between incomplete and complete 7 stable vs unstable stable: normal peripheral attachments with an intact posterior meniscofemoral ligament unstable (also known as a Wrisberg variant): lack or tear of a posterior meniscocapsular (in particular meniscopopliteal) ligaments with an attachment only from the meniscofemoral ligament of Wrisberg 4 anterior or posterior mega horn Radiographic features Plain radiograph Radiographs may well suggest the diagnosis with the widening of the lateral joint space and cupping of the lateral tibial plateau, which is normally flat or even slightly convex. Additionally, there may be associated hypoplasia of the lateral tibial spine. MRI On coronal imaging, meniscal body width of 15 mm or more is typically considered diagnostic of discoid morphology. Alternatively, a ratio of the minimal meniscal width to the maximal tibial width of more than 20% may be used 7,8. On sagittal imaging, the body of the lateral meniscus is normally only seen on two adjacent slices. A discoid meniscus is usually present if the meniscal body is seen on three or more standard sagittal slices - the opposite of the absent bow tie sign. Treatment and prognosis Ideally, the meniscus is preserved with conservative management. If this is unsuccessful, then partial or total resection may be carried out. Complications meniscal tears intrasubstance mucinous degeneration early bony degenerative change

Answer 36

Osteoarthritis =degenerative joint disease = abnormal stress with minor+ major traumatic episodes Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric I asymmetric './ joint space narrowing './ subchondral eburnation './ marginal osteophytes +small ossicles './ radial subluxation of 1st metacarpal base 0 Radiocarpal joint normal unless history of trauma

Answer 37

Popliteal fibular liament injuries MCL Tears

Answer 38

Rectus femoris AIIS avulsion ## Footnote Introduction An apophyseal avulsion injury seen in adolescent athletes Epidemiologydemographics most often in adolescents between the ages 14-17 males more often than females occurs most often in sports involving kicking Pathophysiologymechanismtypically occurs due to eccentric contraction of the rectus femoris (femoral n.) as hip extends and knee is flexed causes avulsion of its anatomic origin off the pelvis Anatomy Anterior inferior iliac spine a bony prominence just above acetabulum is the origin of the direct head of the rectus femoris (femoral n.) Presentation History sudden "pop" in pelvis Symptoms pain and weakness Physical exam antalgic gait anterior hip pain and hip flexion weakness Imaging Radiographs show avulsion of AIIS Treatment Nonoperativebed-rest, ice, activity modificationindications almost all treated nonoperatively techniquehip flexed for 2 weeks position lessens stretch of affected muscle and apophysis follow with guarded weight bearing for 4 week Complications Loss of reduction Delayed union

Answer 39

Psoriatic arthritis 1. Rh Neg 2. a/w Psoriasis 3. distal 4. errosive + Proliferative 5. 60% are HLA-B27 6. **acro-osteolysis** 7. **Pencil-in-cup** 8. **Sausage digit** 9. **"telescoping fingers"** 10. **“mouse ears”** 11. **ivory phalanx:** * Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. * negative for rheumatoid factor and hence classified as one of the seronegative spondyloarthritides. * Epidemiology * Overall prevalence is ~0.5% (range 0.1-1%) * ~25% (range 6-41%) of patients with psoriasis * no gender predilection in psoriatic arthritis * median age of diagnosis is 48 years * Clinical presentation * Dermatological features of psoriasis precede arthritis in ~65% (range 60-70%) whereas arthritic symptoms proceed dermatological features in 15-20% 11. * There is a strong association with nail involvement, particularly for distal interphalangeal joint arthritis. * It most commonly presents as an asymmetrical oligo-arthritis with spondylitis common; oligo-arthritis may progress to polyarthritis in the clinical course of the disease 10,11. * Pathology * Both environmental and genetic factors are thought to play a role. Up to **60% are HLA-B27** positive 2. A proportion of patients have serum rheumatoid factor 6. * Extra-articular manifestations are common 11: * ocular: * uveitis, conjunctivitis * gastrointestinal: * inflammatory bowel disease * cardiac: * rhythm disturbances (e.g. bundle branch block) * urogenital: * urethritis, prostatitis, balanitis, cervicitis, vaginitis * Associations * obesity * hypertension * insulin resistance / type 2 diabetes * hyperlipidaemia * Radiographic features * **The hallmark** * the **combination of erosive change with bone proliferation** * predominantly **distal** distribution (e.g. interphalangeal more than metacarpophalangeal joints). * The disease most commonly involves the **hands**, followed by feet. * It can also affect sacroiliac joints and spine. * Knees, elbows, ankles, and shoulders are less frequently involved 2. * In the hands and feet, the pattern of distribution may be that of a * symmetric polyarthropathy, or * asymmetric oligoarthropathy * distal predominance. * Imaging findings include: * **"pencil-in-cup"** deformities are common, but not pathognomonic for PsA 3 * bone proliferation results in an irregular, “**fuzzy**” appearance to the bone around the affected joint 2 * joint **subluxation** or interphalangeal ankylosis may be present * **periostitis**: may appear as a periosteal layer of new bone, or as irregular thickening of the cortex itself 2 * **“sausage digit”** which refers to soft tissue swelling of a whole digit; ultrasound examination of a sausage digit demonstrates underlying **synovitis and tenosynovitis** 4 * **acro-osteolysis** 12 * **arthritis mutilans:** osteolysis and articular collapse can cause a phenomenon referred to as **"telescoping fingers"** * **ivory phalanx:** classically involving the distal phalanx of the great toe * sacroiliitis: often asymmetrical * spondylitis: asymmetric paravertebral ossifications and relative sparing of the facet joints * Differential diagnosis * rheumatoid arthritis * there is an MCP joint predominance in rheumatoid arthritis (RA) vs interphalangeal predominant distribution in PsA * bone proliferation not a feature in RA * osteoporosis not a feature in PsA * erosive osteoarthritis * “gull-wing” central erosions are present in erosive OA vs **“mouse ears”** peripheral bare area erosions in PsA * reactive arthritis (Reiter syndrome) * tends to involve feet \> hands

Answer 40

Gaucher disease Dr Tristan Skalina and Zara Oozeerally et al. Gaucher disease (GD) is the most common lysosomal storage disorder in humans. It is an autosomal recessive, multisystem disease arising from a deficiency of glucocerebrosidase or beta-glucosidase activity, resulting in the accumulation of a glycolipid (glucocerebroside) within the lysosomes of macrophages, particularity in the bone marrow, spleen and liver. Epidemiology Type 1 is the most common, affecting 1:500-1,000 Ashkenazi Jews and 1:50,000-100,000 of the general population 7. Types 2 and 3 are considered much rarer. Clinical presentation Age of presentation depends on the type of Gaucher disease: type 1 (most common form) age of presentation varies widely, with the mean age of diagnosis being 21 years of age 6 some patients present in childhood while others remain asymptomatic throughout life clinical presentation tends to be with skeletal symptoms (bone pain, pathological fractures, osteonecrosis and bone crises ) 4, hepatomegaly, splenomegaly, and haematological disturbances type 2: evident by 6 months of age, with progressive neurological deterioration resulting in death by the age of 1 or 2 type 3: presents with mild neurological complications by late adolescence or early childhood 6 Pathology Genetic changes The glucosylceramide beta (GBA) gene provides instructions for making ß-glucocerebrosidase. Mutations in the GBA gene reduce or eliminate the function of this lysosomal enzyme leading to a build-up of toxic glucocerebroside and related substances in various tissues and organs 7. Classification Three types of Gaucher disease are described, each with different manifestations 1: type 1 (non-neuropathic form or adult form): commoner type; progressive hepatomegaly, splenomegaly, anaemia and thrombocytopenia, and marked skeletal involvement; lungs and kidneys may also be involved, but the CNS is spared type 2 (acute neuropathic form or infantile form): severe progressive neurological involvement with death by 1 to 2 years of age; hepatomegaly, splenomegaly, is also present (usually evident by 6 months of age) type 3: type 1 with neurological involvement Radiographic features Plain radiograph Skeletal involvement is seen in 70-100% of patients and primarily involves long bones (tibia, humerus, femur) as well as vertebrae. Ribs, hands and wrists, ankles and feet, and mandible may also be involved 6. Features of skeletal involvement include: osteopenia osteonecrosis pathological/crush fractures endosteal scalloping Erlenmeyer flask deformities H-shaped vertebrae paranasal sinus obliteration due to medullary expansion 9 MRI spleen massive splenomegaly splenic nodules (30%) 1 splenic infarcts (33%) liver hepatomegaly: less marked than the degree of splenomegaly T2: hyperintense stellate areas representing inflammation and fibrosis 3 areas of hepatic ischaemia skeletal system long bones are most severely affected reduced T1 and T2 signal from involved bone marrow (due to infiltration of Gaucher cells) bone marrow burden (BMB) score may be obtained from MRI images 4 may give a "salt and pepper pattern" due to scattered involvement features of superimposed osteonecrosis metaphyseal notching of humeri pathological fractures Erlenmeyer flask deformity Treatment and prognosis Enzyme replacement with macrophage-targeted glucocerebrosidase has been shown to be highly effective in type 1 GD, halting the progression and even reversing both bone marrow and visceral infiltration 5. Radiographically, hepatomegaly and splenomegaly respond more rapidly than skeletal changes. Glucosylceramide synthase inhibitors are available for patients with type 1 GD who cannot receive enzyme replacement therapy 8. Complications osteonecrosis of the hip 8 pathological fracture and pyogenic osteomyelitis 10 lung involvement 8 pulmonary infiltration by Gaucher cells (type 2) parenchymal infiltration with fibrosis (type 3) pulmonary hypertension 12 increased frequency of multiple myeloma, Parkinson disease and Lewy body dementia 8 Gaucheromas: rare pseudotumours comprising a mass of Gaucher cells 11 History and etymology First described by French physician Philippe CE Gaucher (1854-1918) in 1882, while still a medical student 2.

Answer 41

Hereditary multiple exostoses/ Dr Yusra Sheikh◉ and Assoc Prof Frank Gaillard◉◈ et al. Hereditary multiple exostoses, also known as **diaphyseal aclasis o**r osteochondromatosis is an autosomal dominant condition, characterised by the development of multiple osteochondromas. Epidemiology Hereditary multiple exostoses demonstrate an autosomal dominant inheritance pattern, with incomplete penetrance in females. The number of exostoses, the degree, and type of angular deformity, and even the rate of malignant transformation varies significantly, even within families. Clinical presentation Most patients are diagnosed by the age of 5 years, and virtually all are diagnosed by the age of 12 years. Patients may be asymptomatic with a few small lesions or may be significantly deformed by multiple large osteochondromas. Radiographic features Except that they are multiple, imaging features are identical to solitary osteochondromas. The skeletal distribution of lesions can significantly vary, with some authors noting that the typical distribution is bilateral and symmetric, whereas others report a strong unilateral predominance. Often associated with a broadened shaft at the end of long bones, hence the term diaphyseal aclasis. Complications Are also similar or those of solitary osteochondroma and include: vascular impingement neural impingement fracture bursitis deformity and ankylosis malignant transformation Malignant transformation is more common than in sporadic cases, with transformation rates reported as high as 25% (lower rates of 3-5% have also been published) 3. The mnemonic GLAD PAST 1 lists the associations with sarcomatous transformation. Refer to the generic osteochondroma article for more information. See also exostosis

Answer 42

over kick of a ball

Answer 43

Laboratory Studies A complete blood count (CBC) is useful for evaluating leukocytosis and anemia. Leukocytosis is common in acute osteomyelitis before therapy. The leukocyte count rarely exceeds 15,000/µL acutely and is usually normal in chronic osteomyelitis. the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) level are usually increased. [24, 2, 25] In metastatic and some metabolic bone disease, alkaline phosphatase (ALP), calcium, and phosphate are elevated, but they are within normal limits in osteomyelitis. [26] Blood cultures are positive in only 50% of cases of osteomyelitis. [9] They should be obtained before or at least 48 hours after antibiotic treatment

Answer 44

2019 Aug q100 ## Footnote Crescent sign of osteonecrosis Dr Magdalena Chmiel-Nowak◉ and Assoc Prof Frank Gaillard◉◈ et al. The crescent sign refers to a linear cleft due to subchondral fracture in the setting of osteonecrosis. It was originally described as a radiographic finding, however, it can also be seen on cross-sectional imaging. In the setting of Legg-Calve-Perthes disease, it heralds the beginning of the fragmentation phase (stage 2). Pathology The cause of the crescent sign is bone trabeculae failure, leading to subchondral fracture. The fracture may propagate through the subchondral bone plate to the joint space, with a formation of an unstable osteochondral flap. Location The crescent sign is most often seen in the femoral and humeral head, as well as the scaphoid, lunate and talus. Radiographic features Radiograph The crescent sign is seen as a curvilinear lucent subchondral line. If articular surface flattening is present, it suggests an impending articular collapse. In the femoral head, it is present usually in its anterior or anterolateral part. Both frontal and frog-leg views should be obtained for assessment. CT A subchondral fracture line is seen. Additionally, a presence of gas may be detected within the fracture cleft. MRI Subchondral fracture cleft may be filled with fluid. A presence of bone marrow oedema distally from the fracture line indicates stress reaction and a very high likelihood of trabeculae collapse. Radiology report Various classification systems of osteonecrosis use the presence of the crescent sign in the assessment of the adult femoral head osteonecrosis 5. Its presence (without more advanced findings) indicates: grade III of Ficat and Arlet classification grade III of Steinberg classification (mentioning the extent of involvement as mild, moderate or severe) grade III of ARCO classification

Answer 45

* Paget disease * Previous Radiation (3-50yrs) * dedifferentiated chondrosarcoma

Answer 46

Fish vertebra Dr Rohit Sharma and Dr Jeremy Jones◉ et al. Fish vertebra, also known as codfish vertebra, describes the biconcave appearance of vertebrae (especially lumbar vertebrae). Pathology Seen in: **_osteoporosis_** sickle cell disease hereditary spherocytosis homocystinuria renal osteodystrophy osteogenesis imperfecta thalassemia major (rarely) History and etymology The term fish vertebrae is attributed to by Fuller Albright (1900-1969), American endocrinologist. In 1941, he used the term to describe the likeness of the biconcave shape of human vertebrae to the biconcave shape of fish vertebrae; although the species was unspecified. In 1948, Fuller Albright and Edward Reifenstein (1908-1975), an American endocrinologist, provided images of codfish vertebra to illustrate the deformation of vertebral bodies seen in postmenopausal osteoporosis 5, hence the term codfish vertebrae.

Answer 47

Elbow terrible triad * fracture of the coronoid process * Radial head and * Posterior elbow dislocation The terrible triad of the elbow is a severe elbow fracture-dislocation pattern and is so-called because it has poor medium-to-long term outcome. Epidemiology The terrible triad primarily occurs in adults; the flexibility of ligaments in children make this constellation unlikely 4. Pathology Mechanism Most commonly due to a fall onto an outstretched hand, not necessarily high-energy, with the arm in semi-flexion and supination 3. Radiographic features The terrible triad of the elbow is the association of 1,2: posterior elbow dislocation coronoid process fracture radial head fracture

Answer 48

* Sclerosis, joint spaces narrowing * Osteophytes * Subchondral cysts/geodes * Asymmetric JSN due to chondromalacia * Subcondral nbone sclerosis * Subchondral cysts (geods) * Marginal osteophytes * Hand and wrist * DIP - herbedens * PIP - bouchards * Thumb - zig zag BOT *

Answer 49

Medial collateral ligament (MCL) injuries are graded into three groups on MRI, much in the same way as many other ligaments: grade 1: (minor sprain) high signal is seen medial (superficial) to the ligament, which looks normal grade 2: (severe sprain or partial tear) high signal is seen medial to the ligament, with high signal or partial disruption of the ligament grade 3: complete disruption of the ligament As a general rule, the MCL is not repaired in the general population if it is an isolated injury. In athletes, grade 3 injuries often require surgical repair 1. After a few weeks, it may appear as a Pellegrini-Stieda syndrome or a Pellegrini-Stieda (PS) lesion, a post-traumatic/post-avulsion calcification of the proximal medial collateral ligamen

Answer 50

ABC that looks like a NOF

Answer 51

Arcuate sign (knee) Dr Dai Roberts◉ and Assoc Prof Frank Gaillard◉◈ et al. The arcuate sign is often a subtle but important finding on knee x-rays and represents an avulsion fracture of the proximal fibula at the site of insertion of the arcuate ligament complex, and is usually associated with cruciate ligament injury (~90% of cases) 2. The fracture fragment is attached to the lateral (fibular) collateral ligament, the biceps femoris tendon, or both. Clinical presentation The fracture results most often from a direct blow to the anteromedial tibia when the knee is extended, resulting in posterolateral subluxation of the tibia in external rotation 1,3. Alternatively, sudden hyperextension of the knee with the tibia internally rotated may cause the same injury 1. The importance of this injury is that if it is not diagnosed acutely, posterolateral instability may develop which is challenging to correct, and may result in failed cruciate ligament reconstruction 1,3. Radiographic features The shape and size of the avulsed fracture vary according to which ligaments are responsible. Plain radiograph The avulsion fracture is usually small, \<1 cm in size, and involves the styloid process of the fibula. It is displaced superiorly and medially. Occasionally the fracture may be larger and extends to include the lateral aspect of the proximal fibula. Slight internal rotation AP films are usually best to radiographically demonstrate this injury 3. MRI MRI can delineate the soft tissue component of the injury as well as to evaluate associated injuries that are common. Associated findings include 2: cruciate ligament injuries especially posterior cruciate ligament 3 bone bruises anteromedial femoral condyle: 50% anteromedial tibial plateau: 28% meniscal tears medial meniscus: 28% lateral meniscus: 22% popliteus muscle injury: 33% medial collateral ligament injury: common 3 Differential diagnosis Segond fracture avulsion is from the tibia fragment more medial and anterior

Answer 52

Based on MRI (where as AO based on CT). Gives values/points to 3 categories: * Injury morphology * PLC intergtity * (intact 0 * inderterminate 2 * disrupted 3 * LFlavum * Facet joint capsule * Spra spinouslifgament * interspinous ligament * Involvement of the neuraxis * Intact * nerve root injury * c SCI * Incomple SCI * Cauda equina injury * Fractues can be divided into * compression * 1 simple * 2 Burst * 2 Coronal plane deformity \>15 * translation 3 * * distraction 4 *

Answer 53

Rheumatoid arthritis * SYNDROMES * **Felty syndrome:** * rheumatoid arthritis, splenomegaly, and neutropenia * **Caplan syndrome** * rheumatoid arthritis and pneumoconiosis * MARKERS * **rheumatoid factor (RF):** * is an IgM antibody against FC portion of the IgG antibodies, and is a traditional marker but is non-specific; associated with several autoimmune and chronic infectious diseases * **anti-cyclic citrullinated peptide (anti-CCP)/anti-citrullinated plasma antibody (ACPA):** * it is more than 80% sensitive and more than 95% specific * **elevated CRP or ESR** * **KEY WORDS** * Proximal (PIP, MCP, wrists) * Pannus * Ulnar styloid * Symmetrical * Osteoporosis (periarticular) * soft tissue swelling * triquetrum * **DIP joints are spared.** * **ulnar deviation** of the MCP joints * **boutonniere** * **swan neck deformities** * hitchhiker’s thumb deformity * **scallop sign:** erosion of the ulnar aspect of the distal radius which may be predictive of extensor tendon rupture (Vaughan-Jackson syndrome) * **pencil-in-cup deformity**: _classically psoriatic_ arthropathy but well-recognised in rheumatoid arthritis

Answer 54

Die-punch fractures result from an axial loading force on the distal radius. It is an intra-articular fracture of the lunate fossa of the distal radius 1. It is by definition depressed or impacted and is named after the machining technique of shearing a shape, depression or hole in a material with a die implement or cutter used in the tool-and-die trade (Figure 1). The die-punch mechanism classically involves the lunate fossa of the radius but can occur from any loading injury 2.

Answer 55

* GOUT * Overhanging juxta-articular erosions, dense soft tissue tophi. multilocular intraosseous tophi * any joint * May not see calcs/crystals. Looks like clouding/hazing * Overhanging edges * small joints of the hands and feet * Joint spaces are typically preserved until late in the course of the disease * Bursal inflammation * No oedema in adjacent bone -\> a lack of oedema on MRI would make you think of gout * MRI * TOPHI Low intermediate sig on T1 and T2 * little enhancement

Answer 56

runs thru hoffas fat pad can look like a tear tears in the anterior horn are rare

Answer 57

Case courtesy of Dr Benoudina Samir, Radiopaedia.org, rID: 51849 On the frontal view: Stylo-scaphoid osteoarthritis. Radio-scaphoid osteoarthritis. Capitolunate osteoarthritis. On the lateral view: Dorsal tilting of the lunate with dorsal subluxation of the capitate. DISI deformity. Case Discussion SLAC (scapholunate advanced collapse) refers to a specific pattern of degenerative arthritits and subluxation which results from untreated chronic scapholunate dissociation. Watson staging is often used by hand surgeons: I: osteoarthritis of the articulation between the radial styloid and the scaphoid II: osteoarthritis involving the whole radioscaphoid articulation III: osteoarthritis of the radioscaphoid and capitolunate articulations IV: osteoarthritis of the radiocarpal and intercarpal articulations +/- distal radioulnar joint (DRUJ) In this case, it is a Stage III SLAC wrist.

Answer 58

Osteosarcoma Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al. Osteosarcomas are malignant bone-forming tumours. They are the second most common primary bone tumour after multiple myeloma, accounting for ~20% of all primary bone tumours. They can be classified into primary and secondary forms, as well as histologic types, of which conventional osteosarcoma is the most common. Epidemiology Primary osteosarcoma typically occurs in young patients (10-20 years) with 75% taking place before the age of 20 because the growth centres of the bone are more active during puberty/adolescence 3. There is a slight male predominance. Secondary osteosarcoma occurs in the elderly, usually secondary to malignant degeneration of Paget disease, extensive bone infarcts, post-radiotherapy for other conditions, osteochondroma, and osteoblastoma. Associations Paget disease of bone irradiation Rothmund-Thomson syndrome fibrous dysplasia (more common in the polyostotic form) Mazabraud syndrome (rare) Clinical presentation Patients often present with bone pain, occasionally accompanied by a soft-tissue mass or swelling. At times, the first symptoms are related to pathologic fracture. Pathology Location Primary osteosarcomas typically occur at the metadiaphysis of long bones in the appendicular skeleton, most commonly at the following sites: femur: ~40% (especially distal femur) tibia: ~16% (especially proximal tibia) humerus: ~15% Other sites are less common: fibula innominate bone (i.e. os coxae) mandible (gnathic osteosarcoma) maxilla vertebrae Secondary tumours, on the other hand, have a much wider distribution, largely mirroring the combined incidence of their underlying conditions, and thus much have a higher incidence in flat bones, especially the pelvis (a favourite site of Paget disease). Osteosarcomas can be further categorised by anatomic relationship to the bone 3,8: intramedullary/central: ~80% surface: ~10-15% intracortical osteosarcoma: rare extraskeletal osteosarcoma: ~5% Classification The WHO classification of bone tumours lists the histologic types of osteosarcoma, which can be further organised by the state of underlying bone and site of origin within the bone: primary osteosarcomaintramedullary/central conventional osteosarcoma: most common (75-80%) and discussed in this article low-grade central osteosarcoma telangiectatic osteosarcoma small cell osteosarcoma surface parosteal osteosarcoma periosteal osteosarcoma high-grade surface osteosarcoma secondary osteosarcoma Conventional osteosarcomas can be further divided by histological subtype: osteoblastic (most common) chondroblastic fibroblastic Macroscopic appearance Osteosarcomas are bulky tumours where a heterogeneous cut surface demonstrates areas of haemorrhage, fibrosis, and cystic degeneration. Their extension within the medullary cavity is often much more extensive than the bulky part of the tumour would suggest. Areas of bone formation are characteristic of osteosarcomas, with the degree of bone formation varying widely. Microscopic appearance Poorly formed trabecular bone is seen with (in the typical high-grade conventional subtype) cellular pleomorphism and mitoses. Variable amounts of fibrocystic and chondroblastic appearing cells may also be encountered. Markers Serum alkaline phosphatase (ALP) may be raised (particularly with advanced disease). Radiographic features Although plain radiography can provide a lot of information, MRI is used for local staging by assessing intraosseous tumour extension (e.g. growth plate/epiphysis, skip lesions) and soft-tissue involvement. Chest CT and bone scanning have a role in distant staging. Plain radiograph Conventional radiography continues to play an important role in diagnosis. Typical appearances of conventional high-grade osteosarcoma include: medullary and cortical bone destruction wide zone of transition, permeative or moth-eaten appearance aggressive periosteal reaction sunburst type Codman triangle lamellated (onion skin) reaction: less frequently seen soft-tissue mass tumour matrix ossification/calcification variable: reflects a combination of the amount of tumour bone production, calcified matrix, and osteoid ill-defined "fluffy" or "cloud-like" compared to the rings and arcs of chondroid lesions CT The role of CT is predominantly utilised in assisting biopsy and staging. CT adds little to plain radiography and MRI in the direct assessment of the tumour. The exception to this rule is predominantly lytic lesions in which small amounts of mineralised material may be inapparent on both plain film and MRI 4. MRI MRI is proving an essential tool to determine accurate local staging and assessment for limb-sparing resection, particularly for evaluation of intraosseous tumour extension and soft-tissue involvement. Evaluation of the growth plate is also essential as up to 75-88% of metaphyseal tumours do cross the growth plate into the epiphysis 4. T1 soft tissue non-mineralised component: intermediate signal intensity mineralised/ossified components: low signal intensity peritumoral oedema: intermediate signal intensity scattered regions of haemorrhage will have a variable signal (see ageing blood on MRI) enhancement: solid components enhance T2 soft tissue non-mineralised component: high signal intensity mineralised/ossified components: low signal intensity peritumoral oedema: high signal intensity Treatment and prognosis Cure, if achievable, requires aggressive surgical resection often with amputation followed by chemotherapy. If a limb-salvage procedure is feasible, a course of multidrug chemotherapy precedes surgery to downstage the tumour, followed by wide resection of the bone and insertion of an endoprosthesis. The outcome depends on different factors such as age, sex, site, size, and type but the most important predictor is the histologic degree of necrosis post-induction chemotherapy; 90% histologic necrosis is associated with much better prognosis 6. Currently, the 5-year survival rate after adequate therapy is approximately 60-80% 4. The most frequent complications of conventional osteosarcoma are a pathologic fracture and the development of metastatic disease, particularly to bone, lung, and regional lymph nodes. Differential diagnosis General differential considerations include the following: osteomyelitis other tumours metastatic lesion to bone Ewing sarcoma aneurysmal bone cyst When the lesion is at the posteromedial distal femur, consider cortical desmoid Practical points When planning to biopsy a potential sarcoma, the treating surgeon should be consulted to plan the biopsy track as this will require excision to reduce the chance of seeding. A poorly planned track that crosses compartments can result in a more extensive resection, potentially with poor outcomes for the patient.

Answer 59

1. RA 2. CPPD 3. Gout 4. psorisis

Answer 60

* **_Bone bruise_** * marrow contusion of the lateral femoral and tibial condyles and moderate joint effusion. * AKA * bone contusion * trabecular microfracture * Definition * are an osseous injury that results from compression of bone structures. * Pathology * Bone bruises represent trabecular microfractures with haemorrhage and without a discrete fracture line or contour abnormality * They typically appear within 48 hours of injury * can persist for up to six months * Aetiology * Most bone contusions are a result of a direct blow to the bone, traction from avulsion trauma, or load to a subchondral surface * Depending on where bone contusion is seen, the underlying trauma mechanism can be identified. * Complications * They can **progress** to **osteochondritis dissecans.** * Radiographic features * Plain radiography will not demonstrate cancellous features but can show regions of impaction, for example, a Hill-Sachs lesion. * MRI * MRI is the modality of choice when investigating bone marrow. * Bone (marrow) contusion is typically focal and ill-defined with the following signal characteristics 4: * T1: focal hypointense area of bone marrow * T2 fat-saturated: focal hyperintense area of bone marrow

Answer 61

1. RA 2. Psoriasis Effects the bare areas, get marginal errosions effects synovial

Answer 62

ANY ACUTE MONO arthritis this must be top of DDx soft tissue swelling jont distension due to effusions joint narrowing due to rcartilage

Answer 63

Posteromedial corner injury of the knee * Complication * increased stress on the cruciate ligaments and can result in **anteromedial rotatory instability (AMRI) of the knee.** * **Clinical** * seen in athletes * sustained with the knee in valgus. * tenderness along the medial joint line. * Pathology * The structures that comprise the posteromedial corner (PMC) are located between the: * posterior margin of the tibial collateral ligament * and medial border of the posterior cruciate ligament * Structures: * **posterior oblique ligament:** * **injury in virtually all cases with associated instability** * **made of three parts** * **superficial arm** * **tibial arm** * **capsular arm** * **oblique popliteal ligament** * **meniscotibial ligament** * **semimembranosus tendon** * **medial meniscus: posterior third** * **ASSOCIATIONS** * 88% of injuries can be associated with a cruciate ligament injury, overwhelmingly the ACL 1. * Xray * lipohaemarthrosis * fracture of the medial tibial corner * Weight-bearing views can reveal a valgus deformity. .

Answer 64

* Parosteal OSA * Periosteal OSA * Highgrade surface OSA

Answer 65

Tubular Bones 80% * Femur 40% -\> 75% around knee * tibia 15% * humerous 15% Other bones 20% * flat bones * vertebral bodies

Answer 66

valgus stress to flexed knee contusion pattern: lateral femoral condyle and lateral tibial plateau +/- medial femoral condyle from medial collateral ligament (MCL) avulsive stress associated with MCL injuries

Answer 67

Long head of biceps tendon dislocation Dr Joachim Feger◉ and Assoc Prof Frank Gaillard◉◈ et al. Dislocation of the long head of biceps tendon is one of the complications of shoulder injury. The long head of biceps (LHB) tendon is usually located inferiorly in the bicipital groove held there by the biceps pulley (the stabilisation role of the transverse humeral ligament is controversial) 3. As it moves superiorly it arches through the rotator cuff interval where it is held by a sling formed by the superior glenohumeral ligament and the coracohumeral ligament. When this ligament is deficient the tendon is free to dislocate medially. It is often associated with degenerative or traumatic tears of the rotator cuff, specifically tears of the subscapularis tendon. If the tendon of the subscapularis is intact then the tendon is seen lying anterior to it. If, as is common, the subscapularis tendon is also deficient then the tendon of the long head of biceps can prolapse into the glenohumeral joint. Radiographic features MRI Diagnosis is best made on axial MR images, where the bicipital groove is seen to be empty, and the tendon can be identified medially. If the tendon cannot be identified then a complete tear of the tendon should be sought. Ultrasound Non visualisation of long head of biceps tendon in bicipital groove with medially displaced tendon. References Related Radiopaedia articles Tendon pathology tendon pathology tendinopathy tendinitis[+] tendon instability long head of biceps brachii dislocation tenosynovitis[+] tendon tear/rupture[+] Promoted articles (advertising) Painless Chronic Pancreatitis Tied to Exocrine Insufficiency Endocrinology Advisor, 2020 Study: CT, MRI accurately identified long head of the biceps tendon disorders Healio Bifurcation of the long head of the biceps brachii By Peyman Borghei et al., Applied Radiology Surgical Technique: Arthroscopic and subpectoral long head of biceps tenodesis Healio Large rotator cuff tears had high rate of long head of the biceps tendon pathology Healio Acute Subscapularis Tendon Rupture Due to Arm Wrestling Injury By Amy Farkas et al., Applied Radiology Powered by Edit articleShare article Article information ADVERTISEMENT: Supporters see fewer/no ads

Answer 68

arises from medial fem condyle and attahces to prox tibia 3 layers superirical adeventitial middle MCL proper Deep

Answer 69

Findings: Marked widening of the distal radial growth plate across its entire area, with metaphyseal irregularity and cystic change. Band of metaphyseal sclerosis with no osseous destruction beyond this. Metaphyseal erosion and widening with a sclerotic border at the distal radial growth plate is compatible with gymnast wrist Gymnast wrist is a term that is used to describe a variety of chronic overuse injuries of the wrist in gymnasts with an immature skeleton. Gymnast wrist comprises a combination of osseous and ligamentous injuries and usually manifests as a chronic Salter-Harris type I fracture of the distal radial physis on radiography 1. Epidemiology Distal radial physeal injury is common in gymnasts, and occasionally occurs in other sports 2. The distal radius is mostly involved because it bears the primary stressful forces in the wrist joint 1. Clinical presentation Pain with gradual onset and exaggeration by weight-bearing activities while the wrist in extension position. Often, range of motion is normal on physical examination, and frequently swelling and tenderness over the distal radius presents 2. Pathology Gymnast wrist results from repetitive compressive forces applied to the distal radial physeal plate during participation in sports like gymnastics and weight-lifting that place a great tension on the physis and adjacent structures 1. Radiographic features physeal plate widening physeal plate irregularity metaphyseal and less commonly epiphyseal sclerosis and irregularity 1,4 physeal plate bridging/fusion in late stage of the disease 1 Plain radiograph Most of the above-mentioned physeal, metaphyseal and epiphyseal changes are usually evident on radiography 1-3. MRI MRI may be used when radiographs are inconclusive. MRI can demonstrate the greater detail about the physeal cartilage and oedema in the adjacent bones before these changes become visible on radiographs 4. It is worth mentioning that MRI is crucial in high-risk patients with chronic wrist pain because early detection is essential in preventing further damage to the distal radial physis 1. Treatment and prognosis As with similar injuries, the mainstay of treatment is rest with ice packs and anti-inflammatory agents as required. The prognosis is dependant on the stage of the injury and radiographic findings at the time of diagnosis, with splint/cast immobilisation, recovery may take anywhere from one to six months 2. Complications Complications of untreated fracture include: early physeal closure of the distal radius leading to positive ulnar variance and Madelung-type deformity in cases that lack proper treatment or experience a prolonged healing process 1,3,4 triangular fibrocartilage complex (TFCC) injury 4

Answer 70

chordoma of the clivus

Answer 71

Anterior cruciate ligament tear Dr Mohamed Saber and Radswiki◉ et al. Anterior cruciate ligament (ACL) tears are the most common knee ligament injury encountered in radiology and orthopaedic practice. Clinical presentation Patients typically present with symptoms of knee instability, usually after acute trauma. The following signs and symptoms are common: popping sensation at the time of injury, followed by swelling initial inability to weight wear, which improves in a short period knee felt to "gives way" especially during pivoting movement apprehension with an attempt at non-linear movements The combination of the Lachman, pivot shift and anterior drawer tests are used to clinically confirm diagnosis 9. Pathology The anterior cruciate ligament is the most commonly disrupted ligament of the knee, especially in athletes who participate in sports that involve rapid starting, stopping, and pivoting (e.g. soccer, basketball, tennis, netball, and snow skiing). **Associations** **O'Donoghue's unhappy triad** **Segond fracture** **posteromedial corner injury of the knee** **Meniscocapsular separation** Radiographic features In younger patients, avulsion of the tibial attachment may be seen. **Plain radiograph** **deep lateral sulcus sign - depression of lateral femoral condyle representing impaction fracture** **anterior tibial translocation sign** **Segond fracture** **arcuate fracture** **joint effusion** CT Considered to have high specificity and sensitivity in detecting anterior cruciate ligament disruption 6. CT is helpful in characterising the avulsion bone fragment when it is present. MRI Imaging of anterior cruciate ligament tears should be divided into primary and secondary signs. Primary signs are those that pertain to the ligament itself. Secondary signs are those which are closely related to anterior cruciate ligament injuries. Primary signs swelling increased signal on T2 or fat-saturated PD fibre discontinuity abnormal anterior cruciate ligament orientation relative to intercondylar (Blumensaat's) line ACL fibres subjectively less steep than a line tangent to the intercondylar roof (Blumensaat's line) ACL angle (angle between the intercondylar line and ACL) \>15° with the apex of the angle located anteriorly, indicating a less steep ACL line - this indicates a ruptured and collapsed ligament empty notch sign: a fluid signal at the site of femoral attachment at the intercondylar notch, denotes avulsion at the femoral attachment. ACL tears typically occur in the middle portion of the ligament (midsubstance tears) and appear as discontinuity of the ligament or abnormal contour. The signal of the ACL can be more hyperintense on T2. If the angle is still normal and there is a hyperintense signal, a partial rupture is more likely than a complete rupture. ACL tear may only involve one bundle. Imaging signs of isolated posterolateral bundle tear are as follows: gap sign: fluid signal and/or a gap between the medial aspect of the lateral femoral condyle and the lateral aspect of the mid-ACL, can be seen on either axial or coronal MRI images. footprint sign: incomplete coverage of the lateral aspect of the tibial spine of the tibia by the distal ACL attachment, seen only on coronal MRI images 8 **Secondary signs** **Secondary signs include 7:** **bone contusion in lateral femoral condyle and posterolateral tibial plateau** **\>7 mm of anterior tibial translation, also known as the anterior tibial translocation sign or anterior drawer sign** **uncovered posterior horn of the lateral meniscus** **Segond fracture, and to a lesser degree arcuate sign** **reduced PCL angle due to buckling of PCL** **positive PCL line sign** **medial or lateral collateral ligament injury**

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