1
Q
Acetabular protrusio
A
- is the proximal and medial migration of the femoral head through the medial acetabular wall into the pelvis
2
Q
Actin and Myosin
A
3
Q
BCIS
A
- BCIS (Bone cement implantation syndrome) is characterized by a number of clinical features that may include hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance (PVR) and cardiac arrest.
- It is most commonly associated with, but is not restricted to, hip arthroplasty.
- It usually occurs at one of the five stages in the surgical procedure; femoral reaming, acetabular or femoral cement implantation, insertion of the prosthesis or joint reduction.
4
Q
Biopsy
A
STIL DCH MN
- By Surgeon performing the definitive surgery
- TQ no Exsanguination
- In line of incision
- Longitudinal incision
- Direct approach
- Culture all biopsies and biopsy all cultures
- Homeostasis
- Meticulous suturing
- No Drains as possible
5
Q
Bone cement
Powder Polymer
- Polymethyl methacrylate/co-polymer (PMMA)
- Initiator: Benzoyl peroxide (BPO)
- Radio-opacifier: Barium sulphate (BaSO4)/Zirconia (ZrO2)
- Antibiotics (e.g. Gentamycin)
Liquid Monomer
- Methyl methacrylate (MMA)
- Accelerator: N, N-Dimethyl para-toluidine (DMPT)/diMethyl para-toluidine (DMpt)
- Stabilizer: Hydroquinone
A
Polymethyl methacrylate is a man-made acrylic which composes of a liquid monomer and a powdered polymer and when mixed together causes an exothermic reaction to reach the final product.
- It produces mechanical interlocking on hardening
- essentially a grout that fills the space between implnant and bone to provide stability and fixation
6
Q
- Cardiogenic shock - the heart is unable to generate sufficient cardiac output
- Neurogenic shock - hypotension and relative bradycardia from loss of sympathetic tone following
A
- spinal cord inury -
- Septic shock vs. hypovolemic shock
- the key variable to differentiate septic shock and hemorrhagic shock is that systemic vascular resistance is decreased with septic shock and increased with hypovolemic shock
7
Q
Catastrophic Wear -
A
Refers to macroscopic premature failure of polyethylene (PE) due to excessive loading.
Primary variables that lead to catastrophic wear include
- PE thickness
- articular surface design
- kinematics
- PE sterilization
- PE machining
8
Q
Clavicle fracture indication
A
Fracture-Specific
- Displacement > 2 cm
- Shortening > 2 cm
- Increasing comminution (>3 fragments)
- Segmental fractures
- Open fractures
- Impending open fractures with soft-tissue compromise
- Obvious clinical deformity (usually associated with displacement and shortening)
- Scapular malposition and winging at initial examination
Associated Injuries
- Vascular injury requiring repair
- Progressive neurologic deficit
- Ipsilateral upper extremity injuries/fractures
- Multiple ipsilateral upper rib fractures
- “Floating shoulder”
Bilateral clavicular fractures
Patient Factors
- Polytrauma with requirement for early upper extremity weight bearing/arm use
- Patient motivation for rapid return of function (e.g., elite sports or self-employed professional)
9
Q
Clinical trial
A
- Identify a problem/interest to be studied – via literature search
- identify a gold standard to compare to Ask a question
- null hypothesis Design your study Define your population
- inclusion/exclusion criteria
- The methodology of the study
- Power analysis (statistician) for numbers required to able to draw statistically valid conclusions from your results
- Define outcome measures (valid and reproducible)
- Obtain ethics approval – COREC / local committee Register trial Conduct the trial
- Recruit your patients – randomise / double-blinded (masked) / stratification for confounding factors
- Collect your data Analyse your results (stats)
- Interpret your findings, write up your work and publish in peer-reviewed journals
10
Q
CMT - Charcot-Marie-Tooth Disease, also known as peroneal muscular atrophy, is a hereditary motor sensory neuropathy (HMSN) that results in muscles weakness and sensory changes muscle weakness leads to cavovarus foot, scoliosis, and other orthopaedic conditions
A
HMSN Type I - abnormal myelin sheath protein is the basis of this degenerative neuropathy. results in a combination of motor and sensory disturbances. HSMN Type 2- intact myelin sheath with wallerian axonal degeneration that results in mild sensory and motor conduction velocities.
11
Q
Consecutive infected THR
A
- This is a clinical governance emergency – set protocolled action plan is activated
- First priority is the appropriate further care of the patients infected – multidisciplinary team / barrier nursing / appropriate antibiotics Stop elective operating
- Clinical governance ladder - Inform clinical director, medical director, microbiologist, infection control nurse (set up an committee to investigate outbreak)
- Report to national level
- Perform a through investigation as to why this has happened and where in the pt pathway things have gone wrong.
- Look at preop assessment – screening Staff - ? Possible carriers Theatre suite – check laminar flow / instruments / drapes / gowns / masks Check the elective ward
12
Q
Constraint
A
- defined as the effect of the elements of knee implant design that provides the stability needed to counteract forces about the knee after arthroplasty in the presence of a deficient soft-tissue envelope. Determining the amount of constraint necessary can be challenging.
13
Q
Corrosion
A
Refers to the chemical dissolution of metal.
- Galvanic corrosion - dissimilar metals leads to electrochemical destruction in the presence of electrolyte.
- Crevice corrosion refers to corrosion occurring in confined spaces to which the access of the working fluid from the environment is limited.
- Fretting corrosion - a mode of destruction at the contact site from the relative micromotion of two materials or two components
14
Q
Creep
A
The phenomenon of progressive deformation of metal in response to a constant force over an extended period of time
15
Q
Crescent Frx: (Sacroiliac Fracture)
A
involves a combination of ligamentous injury at inferior portion of SI joint, and verticle fracture of the posterior ilium which extends thru iliac crest; - posterior superior iliac spine remain attached to the sacrum; - often occurs as a part of lateral compression fractures; frx often remains stable to vertical forces because sacrospinous and sarcrotuberous ligaments remain intact; - this fracture pattern needs to be distinguished from iliac fractures that extend from the iliac crest into the greater sciatic notch, sparing the sacroiliac joint; - these iliac fractures may be associated with gluteal vascular injuries;
16
Q
Diathesis Heuston
A
Term coined by Hueston Disease starts
- early (<40, ?<50)
- Both Hands
- Radial Sided Involvement
- Family History
- Garrods Pads
17
Q
Distal Humerus Physeal Separation
A
a distal humerus physeal separation is a traumatic fracture usually seen in children under the age of three and is often a birth fracture related to delivery. the fracture pattern should raise suspicion of child abuse. treatment is usually operative closed reduction and pinning. Mechanism vaginal delivery (birth fracture) cesarean section nonaccidental trauma rotational force / twisting
18
Q
Dupuytrens Predictors of Outcome
- Age of patient
- Evidence of Diathesis
- Female Severity of Deformity at the PIPJ
- Smoking
A
Fibroproliferative disorder affecting the palmar and digtial fascia with the formation of pathological collagen cords causing a progressive flexion deformity
19
Q
Early Appropriate Care
A
- Identifies major trauma patients and definitively treats the most time-critical orthopaedic injuries while minimizing the secondary inflammatory response, guided by laboratory parameters of adequate resuscitation popularized in 2013
- Parameters
- lactate of < 4.0 mmol/L
- pH ≥ 7.25
- base excess ≥ -5.5 mmol/L
- Optimal time of surgery goal is to definitively treat spine, pelvis, femur, and acetabulum fractures within 36 hours of injury
- Outcomes decreased delay to surgery decreased complication rates increased hospital revenues main reason for delay to treatment with implementation of this protocol was surgeon decision
20
Q
Effective joint space
A
the space includes all periprosthetic regions that are accessible to the joint fluid and thus particulate debris, has been proposed as a mechanism for migration of particles.
21
Q
Endochondral Ossification:
- Bone replaces a cartilage anlage (template). Osteoclasts remove the cartilage, and osteoblasts make the new bone matrix, which is then mineralized.
- Typical in long bones (except clavicle).
- Primary ossification centers (in shaft) typically develop in prenatal period.
- Secondary ossification centers occur at various times after birth, usually in the epiphysis.
- Longitudinal growth at the physis also occurs by enchondral ossifi cation.
- Also found in fracture callus
A
Enchondral bone formation occurs in
- longitudinal physeal growth
- embryonic long bone formation
- non-rigid fracture healing (secondary healing)
22
Q
Endurance limit
A
defined as the maximal stress under which an object is immune to fatigue failure regardless of the number of cycles
23
Q
Fatigue failure
A
Failure of a material
- secondary to repetitive loading
- above the endurance limit
- below the ultimate tensile strength
- depends on the magnitude of stress
- number of cycle
*
24
Q
Fatigue failure
A
- to failure of a material with repetitive loading at stress levels below the ultimate tensile strength
- The endurance limit is defined as the stress at which the material can withstand 10 million cycles without experiencing fatigue failure.
- Clinically,
- Total hip replacements operate above the endurance limit,
- While total knee replacements operate at the endurance limit, especially the polyethylene component, predisposing the latter to fatigue failure.
25
Femoroacetabular impingement (FAI) occurs when anatomic variation of the hip causes impingement between the femoral-head junction and the acetabular rim during functional range of motion.
* Cam impingement occurs when a prominent head-neck junction contacts the acetabular rim during hip flexion
* * Pincer impingement occurs when the acetabulum has localized or global overcoverage leading to contact of the rim with the femoral head-heck junction during normal hip motion
26
Femur fracture
* \< 6 months • any fracture pattern • Pavlik harness • early spica casting
* 6 months - 5 years
* Stable fracture pattern - early spica casting •
* Lenght unstable fracture pattern -polytrauma, multiple/open fx • traction with delayed spica casting • external fixator
* 5-11 years
* length stable and \<49kg flexible titanium nails •
* length unstable fx (comminuted or spiral) very proximal or distal fx • any weight ORIF with submuscular bridge plating , stainless steel, Enders nails, external fixation
* \> 11 years
* patient weighs \> 49kg (100 lbs) - antegrade rigid intramedullary nail fixation
* proximal or distal fx • severe comminution - ORIF with submuscular bridge plating
27
First generation cementing technique
It involved the hand mixing of cement in bowels. There was only a minimal preparation of the femoral canal and cancellous bone was left in-situ.
The canal was irrigated and suctioned prior to the digital application of cement. The prosthesis was then inserted into the femoral canal.
During the 1980's these techniques were refined.
Steps were taken to reduce the porosity of the cement and thereby increase the fatigue life.
Pressurization of the cement was introduced to improve osseo-integration of the cement and the importance of a good cement mantle around the prosthesis was more clearly understood
28
Flexor Pulley System-Thumb
Thumb Pulleys Oblique pulley (3-5mm) originates at proximal half of proximal phalanx in thumb
* A1-Av-oblique-A2 prevents bowstringing of FPL bowstringing will occur if both A1 and oblique pulleys are cut
* Annular pulleys A1 pulley (4-8mm) at the level of the volar plate at the MCP joint radial digital nerve is closest (2.7mm) ulnar digital nerve is less close (5.4mm) bowstringing will occur if both A1 and oblique pulleys are cut
* Av pulley (annular variable pulley) (4-8mm) between A1 and oblique pulleys
* A2 pulley (5-10mm) contributes least to arc of motion of thumb if A2 is intact, cutting A1 or oblique pulley will not result in bowstringing
29
Flexor Tendons
Annular pulley -
* 5 annular pulleys (A1 to A5)
* A2 and A4 arise from the periosteum
* A1, A3, and A5 arise from the volar plate
* * 3 cruciate pulleys (C1 to C3) collapsible and flexible allows the annular pulleys to approximate each other during digital flexion
30
Foot compartments
9 main compartments (controversial)
* **medial**
* abductor hallucis
* flexor hallucis brevis
* **lateral**
* abductor digiti minimi
* flexor digiti minimi brevis
* **interosseous (x4)**
* **central** (x3)
* superficial
* flexor digitorum brevis
* central
* quadratus plantae
* deep
* adductor hallucis
* posterior tibial neurovascular bundle
31
Ganglion cyst
**A mucin-filled synovial cyst caused by either**
* trauma
* mucoid degeneration
* synovial herniation
**Location**
* Dorsal carpal (70%) - originate from SL articulation
* Volar carpal (20%) - originate from radiocarpal or STT joint
* Volar retinacular (10%) - originate from herniated tendon sheath fluid
* dorsal DIP joint (mucous cyst, associated with Heberden's nodes)
32
Gilulas Arc
1. A curve outlining the proximal convexities of bones of the proximal row
2. A curve outlining the distal concave surface of proximal row
3. a curve following the capitate and hammate
33
Growth plate
R P M D C
5 separate zones which have a role in endochondral bone formation
* Resting or Reserve
* Proliferative
* Maturation
* Degenerative
* Calcification (last 3 = hypertrophic)
34
Indicators of adequate resuscitation
* Urine output 0.5-1.0 ml/kg/hr (30 cc/hr)
* Serum lactate levels (most sensitive indicator as to whether some circulatory beds remain inadequately perfused (normal \< 2.5 mmol/L) )
* gastric mucosal ph
* base deficit normal -2 to +2
35
Mangled Extremity Severity Score (MESS)
**Introduction**
* Used to predict necessity of amputation after lower extremity trauma
**Variables**
* Skeletal and soft tissue injury (graded 1-4)
* Limb ischemia (graded 1-3)
* Shock (graded 0-2)
* Age (graded 0-2)
**Calculation** - score determined by adding scores of components in four categories
**Interpretation** - score of \>7 is predictive of amputation
**Pros** - high specificity for predicting amputation
**Cons** - low sensitivity for predicting amputation
36
**Meta-analysis**
* A meta-analysis is the mathematical and statistical analysis of the combined results of two or more studies that addresses the same hypothesis in the same way
* The basic tenet behind meta-analyses is that there is a common truth behind all conceptually similar scientific studies, but which has been measured with a certain error within individual studies.
* The aim then is to use approaches from statistics to derive a pooled estimate closest to the unknown common truth based on how this error is perceived.
* In essence, all existing methods yield a weighted average from the results of the individual studies and what differs is the manner in which these weights are allocated and also the manner in which the uncertainty is computed around the point estimate thus generated.
37
Miniaci method for frontal plane correction.
* Line 1 represents the planned Mikulicz line for the postoperative correction extending from the center of the hip through the center of the knee, past the ankle.
* Line 2 connects the osteotomy hinge point (H) with the center of the ankle.
* The H point was located on the medial cortex of the proximal tibia at the lower level of tibial tuberosity.
* With H point as the center and the length of line 2 as the radius, an angular arc is drawn from the center of the ankle to the intersection of line 1.
* Line 3 connects the H point with the intersection of line 1.
* The angle formed by lines 2 and 3 is the planned correction angle (A).
* (B) Angle A is now drawn on the prospective site of the osteotomy on the AP radiographs of the knee joint.
* The distance (d) of the two lines at the lateral cortex was measured as the osteotomy wedge base (magnification factor must be considered).
38
MODS
* Multiple dysfunction syndrome is the presence of altered organ function in acutely ill patients such that homeostasis cannot be maintained without intervention.
* * It usually involves two or more organ systems.
* It calls for an immediate intervention
39
Necrotizing Fasciitis
* Type 1 Polymicrobial Typical 4-5 aerobic and anaerobic species cultured: • Most common (80-90%) •
* Seen in immunosuppressed (diabetics and cancer patients) • Postop abdominal and perineal infections
* Type 2 Monomicrobial • Group A β-hemolytic Streptococci is most common organism isolate , Seen in healthy patients , Extremities
* Type 3 Marine Vibrio vulnificus (gram negative rods) • Marine exposure
* Type 4 MRSA
LRINEC Scoring system score \> 6 has PPV of 92% of having necrotizing fasciitis
1. CRP (mg/L) - ≥150: 4 points
2. WBC count (×103/mm3) \<15: 0 points 15–25: 1 point \>25: 2 points
3. Hemoglobin (g/dL) \>13.5: 0 points 11–13.5: 1 point \<11: 2 points
4. Sodium (mmol/L) \<135: 2 points
5. Creatinine (umol/L) \>141: 2 points
6. Glucose (mmol/L) \>10: 1 point
40
**O'Driscoll**
2 principles must be satisfied
* fixation in the distal fragment must be maximized and
* all fixation in distal fragments should contribute to stability between the distal fragments and the shaft.
There are 8 technical objectives by which these principles are met:
* every screw in the distal fragments should pass through a plate
* engage a fragment on the opposite side that is also fixed to a plate
* as many screws as possible should be placed in the distal fragments
* each screw should be as long as possible;
* each screw should engage as many articular fragments as possible
* the screws in the distal fragments should lock together by interdigitation, creating a fixed-angle structure
* plates should be applied such that compression is achieved at the supracondylar level for both columns
* the plates must be strong enough and stiff enough to resist breaking or bending before union occurs at the supracondylar level.
41
On tract and Offract
* Hill-Sach's defect is "off-track" and will "engage" on the glenoid if size HS defect \> glenoid articular track
* Hill-Sach's defect is "on track" and will NOT "engage" if HS defect \< glenoid articular track GT=0.83D-d (GT = Glenoid Track, D = diameter of inferior glenoid, d = width of anterior glenoid bone loss) may have implications regarding surgical management
42
Orthotics
An external applied or attached to a body segments which facilitates or improve function by supporting , correcting or compensating for skeletal deformity or weakness.
43
Osteoporosis
* Reduction in bone mineral density with the deterioration of microarchitecture with increased susceptibility to fragility fracture
*
44
Parameters that help decide who should be treated with DCO
* ISS \>40 (without thoracic trauma)
* ISS \>20 with thoracic trauma
* GCS of 8 or below multiple injuries with severe pelvic/abdominal trauma and hemorrhagic shock
* bilateral femoral fractures
* pulmonary contusion noted on radiographs
* hypothermia \<35 degrees C
* head injury with AIS of 3 or greater
* IL-6 values above 500pg/dL
45
Prosthetics elements
* Socket/interface
* Suspension mechanism
* anatomic or self-suspension belts, straps or sleeves
* roll-on locking liners
* suction suspension
* The link
* Terminal device
* Non-energy-storing - SACH,
* multi-axial foot and ankle
* Energy-storing - made of carbon fibre and contain deforming components in the keel
* Energy-storing with hydraulic ankle
* Motor-powered ankles
* Specialized
A prosthesis is a device or artificial substitute designed to replace, as much as possible, the function or appearance of a missing limb or body part.
**Levels**
* Trans-radius - junction of proximal two-thirds and distal third of the forearm
* Trans- humeral - Middle third of the arm
* Trans-femoral - optimum:
* the middle third of thigh; 15 cm above medial knee joint
* Trans-tibial
* 8 cm for every 1 m of height;
* shortest: 7.5 cm measured from the medial knee joint line
* longest: level at which a myoplasty can be performed
46
Screw
Screw - A device to convert rotational forces into linear movement
IM nailing - Load sharing device in which a metal rod is inserted in to the medullary cavity of a bone and across the fracture to provide a solid support for the fractured bone
Plates are stripes of biomaterial that contains holes to accept screws, pegs
Tension band - A device that transforms distraction tensile forces to compression forces by translating the centre of rotation from compression side to tensile side
47
Stirbecks curve
* The term Stribeck curve is used to describe a plot showing the frictional characteristics of a liquid lubricant over conditions usually spanning the Boundary, Mixed and Hydrodynamic regimes
* Each regime is defined by the ratio of the film thickness to the surface roughness, or the λ ratio
* Such curves are often used to evaluate the effect of changes to the lubricant’s viscosity or to the lubricant’s additive package, or the effect of surface roughness
* The primary requirement for generating a Stribeck curve is a fluid that can be drawn into a converging gap, thus creating a pressure increase to support the load
48
Systemic Inflammatory Response Syndrome (SIRS)
* A generalized response to trauma characterized by an increase in cytokines , an increase in complement, an increase in hormones.
* A marker for an individual's generalized response to trauma that likely has a genetic predisposition associated with conditions such as disseminated intravascular coagulopathy (DIC) acute respiratory distress syndrome (ARDS) renal failure multisystem organ failure shock
* Variables
* heart rate \> 90 beats/min
* WBC count \<4000cells/mm³ OR \>12,000 cells/mm³
* respiratory rate \> 20 or PaCO2 \< 32mm (4.3kPa)
* temperature less than 36 degrees or greater than 38 degrees
49
T Tubules
50
**Morel-Lavalle Lesion (MLL) i**
* It is a closed traumatic soft tissue degloving injury characterized by separation of the dermis from the underlying fascia due to a shearing force
* often seen in the polytrauma patient with underlying pelvis or proximal femur fractures
* operative irrigation and debridement recommended for most lesions given the proximity to planned surgical incisions and increased risk of infection
51
The 3 rockers of gait.
* 1st Rocker -
* the heel strikes the ground,
* he foot rotates around this, and the ankle joint axis to come to rest in the flat foot position.
* Contraction of the anterior compartment muscles\* controls this motion.
* 2nd Rocker
* the tibia is brought " up and over " the talus, rotating around the ankle joint.
* The intrinsic muscles of the foot and tibialis posterior fire\* to maintain a medial longitudinal arch
* The terminal portion of the second rocker signals the powerful triceps surae to fire.
* 3rd Rocker
* the ankle plantar flexes over a fixed forefoot (about the metatarsophalangeal joints) ending in toe-off, initiating the swing phase of gait.
52
The ‘spur’ sign
represents the edge of intact ilium adjacent to the fracture, and is pathognomonic of a both-column fracture.
53
Theatre design
The design of a theatre suite in any hospital needs to be carefully thought out in terms of both its position in relation to other areas of the hospital – ITU, wards, A&E, radiology as well as its internal structure. This structure is usually thought of in terms of 4 zones that are intimately linked
* Outer zone – reception (and rest of hospital)
* Clean zone – reception to theatre doors
* Aseptic zone – theatre itself
* Disposal zone – sluices
54
Tillaux Fractures
The mechanism of injury is an external rotational force with stress placed on the anterior tibiofibular ligament, causing avulsion of the distal tibial physis anterolaterally
55
Wolffs law
bone remodels according to the stresses placed across it
Heuter Volkman Law – rate of physeal growth is related to the relative pressures applied across the growth plate.
56
Prosthesis
Knee system
* Four bar linkage
* Stance phase control
* Fluid control
* contstant friction knee - a hinged design to dampen the knee swing by a screw or rubber pad that applies friction to knee bolt
* variable friction - allows resistance to knee flextion to increase as the knee extends by employing a number of staggered friction pads
* mannual locking knee
Suspension system
* trans tibial - gel liner suspension system silicon, Polyurethane, thermoplastic eleastomeres
* the liners provide suspension through suction and friction and acts as socket interface
trans femoral
* vacuun suction - relies on surface tesnion, negative pressure, muscle contration
prosthetic shanks
* endo skeletal - soft exterior and load baring tubing inside
* exoskeltal - hard load bearing esxterior shell
**prosthetic feet - five classes**
* Single axis foot
* SACH - Solid ankle cusion heel
* Dynamic response foot - depends on pts ht, wt, activity and access for maintainance,
* articulated - uselful in activities on uneven surfaces
* non articulated dynamic response - short or long keel
* Energy storing - carbon fiber and deforming componenents in the keel
57
Acetabular dysplasia
58
Cerebral palsy
in 2004 the International Executive Committee for the Definition of Cerebral Palsy revised the definition of cerebral palsy to state
* Cerebral palsy (CP) describes a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to nonprogressive disturbances that occurred in the developing fetal or infant brain.
* The motor disorders of cerebral palsy often are accompanied by disturbances of sensation, perception, cognition, communication, and behavior, by epilepsy, and by secondary musculoskeletal problems.
* **Geographic Classification**
* **Physiologic Classification**
* spastic type, which affects the corticospinal (pyramidal) tracts
* The extrapyramidal types of cerebral palsy include athetoid, choreiform, ataxic, rigid, and hypotonic
* Gross Motor Functional Classification System (GMFCS)
59
Intramembranous Ossification
* Bone develops directly from mesenchymal cells without a cartilage anlage.
* Mesenchymal cells differentiate into osteoblasts, which produce bone.
* Examples: fl at bones (e.g., the cranium) and clavicle
FRCS
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