knee Flashcards
Meniscal Tears:
higher risk in?
medial tears vs lateral tears?
degen tears in older patients occur in?
oblique/parrot beak tears occur at? tx?
root tear is association?
radial tear?
most sensistive PE findings?
- Higher risk in ACL deficient knee
- Medial tears more common than lateral tears, except in ACL tear when lateral meniscus tears
- degen tear: posterior horn medial meniscus
- oblique tears: junction of posterior horn, bodyof meniscus, mechanical symtoms, repair impossible, tx with partial excision to stable rim
- root tear: functionally a total meniscectomy, lateral root tears ACL, medial root tears chondral injuries
- radial tear: complete radial tear disrupts the circumferential fibers of the meniscus, creating the functional equivalent of a total meniscectomy
- complete disruption of the circumferential meniscal fibers and resultant hoop stresses
- exam: jt line ttp most sensitive
lateral tears 4x more likely than median with an acute ACL injury
medial tears more common degen tear 2/2 its function as secondary restraint
An 18-year-old man sustains a twisting injury to the left knee while playing football. An MRI scan is shown in Figure 48. What is the most likely diagnosis?
lateral mensicus tear
MRI scan shows a displaced, bucket-handle lateral meniscus tear. The sagittal view shows the typical “large anterior horn” sign, or “double meniscus” sign in which the displaced bucket-handle fragment appears just anterior to the native anterior horn of the lateral meniscus. The presence of the fibula on the sagittal view confirms this as the lateral compartment. The image is lateral and the cruciate ligaments are not visualized. The articular cartilage shown does not demonstrate an osteochondral lesion.
partial meniscectomy:
indications?
outcomes?
- tears not amenable to repair (complex, degenerative, radial tear patterns) repair failure >2 times
- > 80% satisfactory function at minimum follow-up
- 50% have Fairbanks radiographic changes. (osteophytes, flattening, joint space narrowing)
- predictors of success age less than 40 yo normal alignment minimal or no arthritis single tear
best candidate for meniscal repair? outcomes?
- peripheral (red-red)
- lower rim width: better ability to heal. distance from tear to peripheral meniscocapsular junction (better blood supply)
- vertical and longitudinal tears (rather than horizontal, radial, or degen)
- 1-cm in length
- root tear
- acute repair combined w/ ACL recont
ouctomes: 70-95%, highest success when done w/ concomittant acl recon (90%), modest w/ intact acl 60, poor results untreated acl deficiency 30%
standard treatment for bucket handle tears
the standard for bucket-handle tears is an** inside-out repair**. **Vertical mattress sutures **have been found to be the strongest suture configuration.
total meniscectomy:
? have significant arthritic lesions and ? have radiographic changes three years after surgery
? have arthrosis at 20 years
severity of degenerative changes is proportional to ? of the meniscus that was removed
20% have significant arthritic lesions and 70% have radiographic changes three years after surgery
100% have arthrosis at 20 years
severity of degenerative changes is proportional to % of the meniscus that was removed
Meniscal repair:
inside-out technique: approach?
all-inside:
outside in repair useful for?
strongest suture?
healing enhanced by?
risks?
inside-out technique: gold standard,
- medial approach to capsule, incise sartorius fascia retract pes/semimembranous posterior, plane b/t medial gastroc and capsule
- lateral approach: IT band/biceps tendon, retract lateral head of gastroc posteriorly
all-inside: most common, allows for tensioning device breakage/iatrogenic chondral injury
outside in repair useful for anterior horn tears
strongest suture? vertical mattress suture capture circumfrential fibers
healing enhanced by rasping
risks? saphenous n/v w. medial approach; peroneal nerve lateral approach
complications? Saphenous neuropathy (7%)
Arthrofibrosis (6%)
Sterile effusion (2%)
Peroneal neuropathy (1%)
Superficial infection (1%)
Deep infection (1%)
inside out lateral approach
splliting b/t IT band and biceps tendon then retract gastrocs posteriorly
posterior-lateral capsular exposure needed to protect the neurovascular structures and allow suturing for an inside-out lateral meniscal repair is performed by developing the interval between the iliotibial band and biceps tendon. The lateral gastrocnemius is then retracted posteriorly and medially where it helps protect the neurovascular structures. Splitting below the biceps tendon puts the peroneal nerve at risk.
meniscal transplant:
indications
most common cause of failure?
Isolated meniscal allograft transplantation has been shown to be most effective in patients with prior total meniscectomy, age less than 50 years, BMI 30 kg/m2, clinical symptoms of pain in the involved tibiofemoral compartment, 2 mm or more of tibiofemoral joint space on a 45-degree weight-bearing AP radiograph, ligamentous stability, neutral mechanical alignment, absence of articular cartilage loss, and no radiographic evidence of advanced arthritis. In the presence of lower extremity malalignment, a high tibial osteotomy (HTO) is often considered before or in conjunction with meniscal transplantation to correct the malalignment.
Graft failure that results from meniscal graft tears is thought to be related to the acellularity of graft tissue
mcmurrary test
McMurray’s test for medial meniscal pathology consists of: flexing the knee, applying a valgus force, placing a hand on the medial joint line of the knee, and finally bringing the knee from flexion to extension while rotating the tibia. A palpable pop or click, or more commonly the elicitation of pain during this maneuver is considered a positive test and can correlate with a meniscal tear.
discoid meniscus
* radiographic findings of discoid meniscus
* mri
* tx
most common cause of a symptomatic clicking or clunking in the knee in a young child.
* * discoid lateral meniscus. Radiographic findings can include lateral joint space widening, squaring of the lateral condyle, cupping of lateral tibial plateau and hypoplasia of the lateral tibial spine.
* Discoid menisci occur in 3-5% of the population. They are usually lateral and may be bilateral in 25-50%.
* Sagittal MRI images showing meniscal continuity in three 5mm sagittal images (“bow-tie sign”) is diagnostic.
* If there is pain, mechanical symptoms, meniscal tear or detachment, arthroscopic debridement and saucerization is indicated. The aim is to preserve a rim of normal meniscus.
PCL injury:
most common mechanism?
bundles?
blood supply?
grading injury?
exam: varus/valgus stress laxity at 0° indicates
most accurate manuever for testing?
tx:
untreated PCL deficiency most commonly results in?
Arthroscopic image of a knee shows the posterior cruciate ligament bundle origins. The anterolateral bundle (ALB) and the posteromedial bundle (PMB) are observed at their origin on the lateral side of the medial femoral condyle (MFC), or the medial intercondylar notch.
- direct blow to the proximal aspect of the tibia, w/ flexed knee (dashboard).
- The most common mechanism of PCL injury in athletes is a fall onto the flexed knee with the foot in plantarflexion, which places a posterior force on the tibia and leads to rupture of the PCL.
- primary restraint to posterior tibial translation, greatest instability at 90 of flexion.
- AL tight in flexion, strongest/most important for stability at 90 “PAL” PCL
- PM tight in extension.
- middle geniculate artery and fat pad
grade 1: partial, 1-5 mm of posterior translation, tibia anterior to fem condyle
grade 2: complete, 6-10 mm of posterior translation, anterior tibia flush with fem condyle
grade 3: combine pcl+capsuloligamentous, >10 mm translation, often associated with ACL injury. - varus/valgus stress laxity at 0° indicates MCL/LCL and PCL injury. (30 deg is just mcl/lcl)
- ** posterior drawer test (90 deg flexion) most accurrate**
- tx: Grade I and II (isolated) nonop w/ quad rehab w/ focus on knee extensor strengthening, proctected wb. Grade III (isolated) extension bracing 4 weeks w/ limited ROM followed by qaud strengthening
- surgery: pcl repair of bony avulsion or recon for PCL+ACL/PLC; PCL + MCL/LCL
- Untreated PCL deficiency most commonly results in increased degenerative changes to the medial and patellofemoral compartments
posterior sag sign: patient lies supine with hips and knees flexed to 90°, examiner supports ankles and observes for a posterior shift of the tibia as compared to the uninvolved knee
the medial tibial plateau of a normal knee at rest is 10 mm anterior to the medial femoral condyle an absent or posteriorly-directed tibial step-off indicates a positive sign
dial test: what indicates plc and pcl
10° ER asymmetry at 30° & 90° consistent with PLC and PCL injury
10° ER asymmetry at 30° only consistent with isolated PLC injury
Posterolateral corner injuries:
missed dx is common cause of?
structures?
function?
where does biceps tendon attach?
exam:
tx?
complications?
- only 28% of PLC are isloated, usually combined PLC>ACL
- missed PLC injury diagnosis is common cause of ACL reconstruction failure
- static: LCL, popliteus tendon, politeofibular ligament
-lateral capsule thickening, arcuate ligament, biceps, politeus muscle, ITB, lateral GH - popliteus works synergistically with the PCL to control external tibial rotation, varus, and posterior tibial translatio
- popliteus and popliteofibular ligament function maximally in knee flexion to resist external rotation
- LCL is primary restraint to varus stress at 5° (55%) and 25° (69%) of knee flexion
- varus alginment, gait, dial test more 10 ER assymettry at 30 deg only is isolated PLC, if 30 at 90 then PLC and PCL
- biceps inserts on the posterior aspect of the fibula posterior to LCL
- complications: peroneal nerve injury, arthrofibrosis, missed PLC injury
- tx: nonop KI in full extension then rehab grade I, PLC repair vs hybrid recon and repair for acute avulsions and tears
avulsion fracture of the fibula (arcuate fracture ) or femoral condyle
ACL injuries: what predisposed female athletes
Different neuromuscular recruitment patterns (high quadriceps-to-hamstring activity ratio) and landing/cutting biomechanics (decreased hip and knee flexion, increased knee external rotation with subsequent dynamic knee valgus) contribute most to the increased incidence of anterior cruciate ligament (ACL) tears in female athletes.
ACL
AM bundle
AL bundle
2 ridges?
blood supply?
exam: lachmans vs pivot
AM tight in flexion, primary restraint to anterior tibia translation (drawer)
PL greater length changes, tightest in extension, rotational stability (pivot shift test)
lateral intercondylar ridge demarcates anterior edge of acl
bifurcate ridge seperates AM and PL bundle attachment
middle geniculate
lachmans: most sensitive (pcl false positive due to posterior subluxation)
- A firm endpoint, B no endpoint: I 3-5 mm translation, II A/B 5-10mm, II a/b >10 mm
- pivot shift: knee brought from extension (anteriorly subluxated) to flexion (reduced) with valgus and internal rotation of tibia reduces at 20-30° of flexion due to IT band tension. evaluates the posterolateral bundle of the ACL, which controls rotational stability
- pivot shift better measure of “functional instability” than instrumented knee laxity or Lachman examination following anterior cruciate ligament reconstruction.
what is this finding called? association?
Segund fx
bony aculsion of anterolateral ligament
pathognominic for acl tear
associated with acl tear 75-100 percent of the time.
where do you see bone bruising w/ ACL injuries?
middle 1/3 of LFC (sulcus terminalis) posterior 1/3 of the lateral tibial plateau subchondral changes on MRI can persist years after injury, may contribute to long-term chondral damage
why must you have full ROM (except meniscal tear causing block) for ACL recon?
lack of pre-operative motion risk factor for post-operative arthrofibrosis
ACL recon
femoral tunnel placement
tibial tunnel placement
Graft failure due to tunnel malposition
Femoral tunnel:
* need 1-2 mm rim of bone between the tunnel and posterior cortex of the femur
* drilling tunnel in over 70 degrees of flexion will prevent posterior wall blowout
* lateral wall 10/2 oclock
tibial tunnel:
sagittal plane: 10-11mm in front of the anterior border of PCL insertion, 6mm anterior to the median eminence, 9mm posterior to the inter-meniscal ligament
coronal plane: tunnel trajectory of less than 75 degrees from horizontal
Graft failure due to tunnel malposition 70 percent of failures
ACL tunnel malpositioning can cause graft failure:
On the femur, vertical tunnel placement causes ? and is best seen on what exam? Anterior tunnel placement leads to? and occurs from ?
Posterior misplacement?
tibial malposition:
too anterior placement? posterior placement?
Graft failure due to tunnel malposition: 70% of failures
vertical tunnel placement: 12oclock position in the notch as opposed to lateral wall 10/2 oclock, causes rotational instability, positive pivot shift
Anterior tunnel placement, tight in flexion loose in extension, failure to clear resident ridge
posterior tunnel (over the top) leads to lax in flexion and tight in extension
Tibial malposition:
too anterior, knee that is tight in flexion w/ roof impingement in extension
too posterior, acl will impingement w/ PCL
LCL:
origin, insertion, blood supply
biomechanics
how to test for isolated LCL injury?
- origin: posterior(3.1 mm) and proximal 1.4mm to lateral epicondyle, posterior and proximal to origin of popliteus
- insertion: anterolateral head of fibula, most anterior on fibula. LCL → popliteofibular ligament → biceps femoris
- anterior tibial recurrent arteries and inferolateral geniculate arteries
- primary restraint to varus stress at 5° and 30° of knee flexion, provides 55/69% of restraint at 5/30°
- located behind axis of knee rotation: tight in extension and lax in flexion
- varus instability at 30° flexion only - isolated LCL injury
- varus instability at 0° and 30° flexion - combined LCL +/- ACL/PCL injuries
LCL injury classification:
treatment?
prognosis?
Grade 1: 0-5 mm lateral joint opening, MRI Subcutaneous fluid surrounding the midsubstance of the ligament at one or both insertions
Grade 2: 6-10 mm lateral joint opening, MRI Partial tearing of ligament fibers at either the midsubstance or one of the insertions
Grade 3: > 10 mm lateral joint opening without a firm endpoint, MRI Complete tearing of ligament fibers at either the midsubstance or one of the insertions
TX: non-op grades I-II if isolated, ROS at 6-8 weeks
- isolated repair if acute gradeIII lcl w/ avulsion from fibula
- isolated recon if subacute/chronic more than 2 weeks grade 2, best results w/ semitendinosis autograft
complications: **persistent varus or hyperextension laxity (non opped grade III injuries missed/concomintant PCL or PLC injury. **
peroneal nerve injury upp to 44% of multi ligs involving the lcl/pcl
Prognosis: LCL healing unrealible depends on degree of injury, does not heal as well as MCL
open vs closed chain exercises
Open chain exercises are those in which the distal limb segment is not fixed. In closed chain exercises, the foot remains fixed to the ground or a base plate. Co-contraction of hamstring and quadriceps is easier to achieve in closed chain exercise, resulting in a more balanced application of force across the knee.
Lateral Patellar compression syndrome
mechanism?
what is the miserable triad?
exam/clinicl symptons
tx?
- tight retinaculum, leas to excessive lateral tilt
- associated with Miserable triad:
- anatomic characteristics that lead to an increased Q angle and an exacerbation of patellofemoral dysplasia.
- femoral anteversion, genu valgum, external tibial torsion/pronated feet
- pain w. stair climbing, pain w/ sitting for long periods
- pain w. compression of patella and moderate facet ttp
- Tx: nsaids, PT w/ vastus medialis strengthening and closed chain short arc quadriceps exercises
- arthroscopic lateral release
- patelar realignment surgery
Idiopathic Chondromalacia Patellae
what is it? how does it present? tx? rehab?
surgery?
- idiopathic articular changes of the patella leading to anterior knee pain.
- anterior knee pain made worse with squatting, prolonged sitting or ascending stairs and pain on patellar compression in knee extension.
- Treatment is generally nonoperative with resting, ice, activity modifications and physical therapy to focus on hamstring, quadriceps and core strengthening.
- rehabilitation with emphasis on vastus medialis obiquus strengthening core strengthening closed chain short arc quadriceps exercises strengthening of hip external rotators
- arthroscopic debridement: outerbridge 2-3 chondromalaxia of PF jt
- lateral retinacular rlease if tight lateral ret capsule, loose medial capsule and lateral patellar tilt
- patellar realignment surgery: severe symptoms that have failed to improve with extensive physical therapy
Pain receptors of the knee
- subchondral bone has weak potential to generate pain signals
- anterior fat pad and joint capsule have** highest potential for pain signals**
Outerbridge MRI Classification of Chondromalacia
Grade 0 Normal Cartilage
Grade I Surface intact and heterogenous; high signal intensity, arthroscopically: softening or swelling of cartilage
Grade II Fissures and fragmentation extending down to the articular surface
arthroscopically: fragmentation and fissuring within soft areas of articular cartilage
Grade III Partial thickness defect, with focal ulceration, arthroscopically: partial thickness cartilage loss with fibrillation (crab-meat appearance)
Grade IV Exposed subchondral bone:
arthroscopically: cartilage destruction with exposed subchondral bone
patellar tendon rupture
Risk factors, systemic vs local?
mechanism?
most ruptures occur w/ knee in what position?
exam?
tx:
- quadriceps tendon rupture is more common than patella tendon rupture (2:1 ratio)
- bilateral ruptures associated w. DM, SLE, RA, and CKD
- Patellar degeneration most common RF
- tensile overload of exensor mechanism, sudden quadriceps contraction with knee in a flexed position (e.g., jumping sports, missing step on stairs
- most ruptures occur with knee in flexed position greatest forces on tendon when knee flexion > 60 degrees
- 3 patterns of injury:
* avulsion with or without bone from the proximal insertion/inferior pole of patella (most common); strain at tendon-bone interface is 3-4x strain at midsubstance; midsubstance, distal avulsion from tibial turbercle - unable to perform active SLR or maintain passively extended knee
- tx: primary repair, KI locked in extension 6 weeks, WBAT immediately, early motion protcol 7-10 days passive extension and active flexion
- tendon reconstruction: chronic tears, severely degenerative tears, allograft or autograft
radiograph shows patella alta consistent with a rupture of the patellar tendon. The MRI scan confirms disruption of the patellar tendon from the inferior pole of the patella.
ratio of patellar tendon force to quads tendon force >1 at <45° and <1 at >45° at smaller flexion angle, patellofemoral contact point is at distal pole of patella, giving quads tendon a mechanical advantage
imaging for patellar tendon rupture:
Insall salvation ratio >
Blackburn-peel ration >
caton-dechamps ration >
“BIC 1,2,3”
Blackburne-Peel ratio > 1.0
Insall-Salvati ratio is > 1.2
Caton Deschamps ratio > 1.3
Insall-Salvati ratio is > 1.2, normal between 0.8 and 1.2
Blackburne-Peel ratio > 1.0 normal between 0.5 and 1.0
Caton Deschamps ratio > 1.3 normal between 0.6 and 1.3
patellar tendon rupture repair options and outcomes, most common complication, most important prognostic factor
Suture anchor tendon repair: atleast 2 achors, higher ultimate load to failure and less gap formation compared to transosseus fixation.
Transosseus repair: not as good, see image
outcomes biomechanical studies have shown less gap formation with suture anchor repair compared to transosseous repair; clinical studies have shown** a significant decrease in re-rupture rate with use of suture anchor compared to transosseous repair.**
complication:
#1 knee stiffness
MUA if flexion less than 120 at 6-12 weeks post op
Lyssis of adhesion if less than 120 after 12 weeks post op
#2 Quadatrophy: does not compromise return of strength
most important prognostic factor for complete tears is ** timing of repair**
Patellar instability
RF?
anatomic factors?
MPFL femoral origin-insertion? primary restraint in first?
stability in deep flexion?
exam: MPFL tenderness, +/- hemarthrosis, increased passive patellar translation can be measured how?
what is the J sign?
Clinical photograph with the knee in flexion (A) and in extension (B). The dotted line delineates the inverted “J” path taken by the patella
RF: ligamentous laxity, previous instability event, miserable malalignment “ fem anterversion, genu valgum, ext tibial torsion, led to increased Q angle
anatomic: patella alta (patella doesn’t articulate w/ sulcus), trochlear dysplasia, excssive lateral patellar tilt, lateral femoral condyle hypoplasia
muscle: dysplastic VMO, overpull of IT band and vastus lateralis
MPFL b/t medial epicondyle and duuctor tubercle, primary restraint in 1st 20-30 degrees of flexion
trochlear groove, patella height, and patellar tracking give stability in deep flexion. dynamic stability provided by vastus medialis
patellar translation: normal less than 2, neutral is 0. lateral transtion of medial morder of patella to lateral edge of trochlear groove is consider 2 quadrants and is abnormal
J sign: excessive lateral translation in extension which “pops” into groove as the patella engages the trochlea early in flexion associated with patella alta
Schottle’s point which can be reliably found radiographically just anterior to the posterior femoral cortex, and proximal to Blumensaat’s line on a lateral radiograph. 1 mm anterior to a line extending from the posterior femoral cortex, 2.5 mm distal to the posterior origin of the femoral condyle, and proximal to Blumensaat’s line, which is the anatomic femoral insertion of the medial patellofemoral ligament (MPFL).
trochlear dysplasia on lateral view: what 3 signs to look for?
crossing sign trochlear groove lies in same plane as anterior border of lateral condyle represents flattened trochlear groove
double contour sign anterior border of lateral condyle lies anterior to anterior border of medial condyle representsconvex trochlear groove/hypoplastic medial condyle
supratrochlear spur arises in proximal aspect of trochlea
TT-TG
what does it measure and whats abnormal
measures the distance between 2 perpendicular lines from the posterior cortex to the tibial tubercle and the trochlear groove >20mm usually considered abnormal
treatment for patellar instability? 1st time w/o loose bodies or articular damage
1st time w/o loose bodies or articular damage: NSAIDS, activity modification, and physical therapy
emphasis on strengthening closed chain short arc quadriceps exercises Quad strengthening core and hip strengthening to improve limb positioning and balance (hip abductors, gluteals, and abdominals) patellar stabilizing sleeve or “J” brace consider knee aspiration for tense effusion positive fat globules indicates fracture
Operative tx for patellar instability?
arthroscopic debridement?
MPFL repair?
MPFL recon?
Fulkerson?
Distalization?
when is a lateral release ok?
- Arthroscopic debridement (removal of loose body) vs Repair with or without stabilization
- MPFL repair indications acute first time dislocation with bony fragment, direct repair performed in a few days
- MPFL reconstruction with autograft vs allograft for recurrent instability
- Fulkerson-type osteotomy (anterior and medial tibial tubercle transfer) TTTG>20 with MPFL recon
- tibial tubrcle distalization for patellar alta
* lateral release/lengthening: isolated release no longer indicated for instability, lateral lengthening has shown better outcomes, less quadriceps atrophy, and lower incidence of medial patellar instability. only indicated if there is excessive lateral tilt or tightness after medialization
gracilis or semitendinosus commonly used (stronger than native MPFL)
femoral origin can be reliably found radiographically (Schottle point)
a femoral tunnel positoined too proximally results in graft that is too tight (“high and tight”)
patellar instability MPFL reconstruction outcomes:
- severe trochlear dysplasia is the most important predictor of residual patellofemoral instability after isolated MPFL reconstruction
- rate of recurrent instability does not differ with regard to graft choice (allograft vs. autograft vs. synthetic graft)
patellar instability complications:
recurrent dislocation rates w/ non op?
- redislocation rates with nonoperative treatment may be high (15-50%) at 2-5 years recurrence rate is highest in those patients who sustain a primary dislocation under the age of 20
- Medial patellar dislocation and medial patellofemoral arthritis almost exclusively iatrogenic as a result of prior patellar stabilization surgery
Microfracture
* generates a much higher concentration of
* function
* best used for
* limitations?
- relies on formation of type 1 and 2 cartilage
- type I fibrocartilage than type II hyaline cartilage.
- penetrate the subchondral plate and recruit mesenchymal cells to form fibrocartilage.
- smaller lesions less than 2 cm2, where the subchondral bone is penetrated by a sharp awl which helps to release marrow elements in order to stimulate new cartilage formation
- best results for acute, contained cartilage lesions less than 2 cm x 2cm
- poor results for larger defects >2 cm x 2cm, does not address bone defects, requires limitation of WB 6-8 weeks
protected weight bearing and continuous passive motion (CPM) are used while mesenchymal stem cells mature into mainly fibrocartilage
Osteochondritis dissecans (OCD) more commonly involves in what knee location in catchers and adolescents?
How are they managed in skeletally immature?
- posterior femoral condyle in catchers compared to position players, likely due to the repetitive and persistent loading of the knees in a hyper-flexed position. “catchers knee”
- Overall, OCD lesions of the knee most commonly involve the** posterolateral aspect of the medial femoral condyle**
- Stable lesions in skeletally immature patients should initially be managed non-operatively
- Unstable juvenile lesions (fluid or cyst underneath lesion), as well as, stable lesions that fail to heal with non-operative treatment require surgical treatment.
osteochondral allografts
OCA is helpful for what kind of lesions
- OCA is helpful in cases where cartilage lesions are large (>4cm^2), uncontained, or when there is significant involvement of the underlying subchondral bone
- Involvement of the patellofemoral joint (PFJ) places this patient at increased risk of failure after an osteochondral allograft transfer
- Patella instability and mechanical alignment should be addressed before or at the time of the cartilage procedure to improve the overall outcome.
- fresh, refrigerated grafts are used which retain chondrocyte viability
- The chondrocytes in the graft remain viable, the transferred cartilage heals, and biopsy reveals articular cartilage composed primarily of type II collagen.
only FDA approved cell therapy for cartilage in the USA and when successful, results in a healed lesion consisting of both Type I and Type II collagen, with type II collagen predominating
Matrix-associated autologous chondrocyte implantation (MACI)
Type I collagen is the most common collagen in the body and is found in bones, ligaments, tendons etc, whereas, type II collagen is found in articular (hyaline) cartilage. MACI is a two-stage procedure which uses autologous chondrocytes cultured on a porcine collagen membrane for the treatment of large chondral lesions in the knee. This is the third generation of chondrocyte implantation technology and is the first to utilize a scaffolding to grow chondrocytes. During the second stage of the procedure, the matrix can be secured with fibrin glue or sutures. Upon healing of the lesion, both type I and type II collagen can be identified
OATS
Osteochondral allograft transplantation is performed with the goal of replacing cartilage defect with
- live chondrocytes in mature matrix along with underlying bone
- theoretical advantage of autologous chondrocyte implantation is the development of hyaline-like cartilage rather than fibrocartilage in the defect, which presumably leads to better long-term outcomes and longevity of the healing tissue.
intact, viable articular cartilage and its underlying subchondral bone offers the ability to address large osteochondral defects of the knee,
chronic ACL tear, most common location of osteochondral lesion
anterior aspect of lateral femoral chondyle and posterolateral tibial plateau
osteochondritis dissecans 70% of lesions found where
70% of lesions found in posterolateral aspect of medial femoral condyle
impaction forces greater than ? will disrupt normal cartilage
impaction forces greater than ** 24 MPa** will disrupt normal cartilage
MRI is most sensitve for evaluating focal osteochondral lesions, what sequences offer improved sensitivity and specifity over standard sequences?
most sensitive for evaluating focal defects
- Fat-suppressed T2
- proton density
- T2 fast spin-echo (FSE) offer improved sensitivity and specificity over standard sequences
Fixation of unstable ocd fragements:
what do you need?
best results for?
limitations?
- need osteochondral fragment with adequate subchondral bone
- best results for unstable osteochondritis dissecans (OCD) fragments in patients with open physis
- nonabsorbable fixation (headless screws) should be removed at 3-6 months
- lower healing rates in skeletally mature patients
MACI overview
- cells are cultured and embedded in a matrix or scaffold results in Type I and Type II collagen
- matrix secured with fibrin glue/sutures
- results in type I and II collagen
- only FDA approved stem cell therapy for cartilage
- 2stage, expesive
ACI
overview:
technique:
benefits:
limitatins
ACI for patellar chondral defect
- cell therapy with goal of forming autologous “hyaline-like” cartilage
*technique: arthroscopic harvest of cartilage from a lesser weight bearing area in the lab, chondrocytes are released from matrix and are expanded in culture defect is prepared, and chondrocytes are then injected under a periosteal patch sewn over the defect during a second surgery benefits may provide better histologic tissue than marrow stimulation long term results comparable to microfracture in most series include regeneration of autologous tissue, can address larger defects - benefits may provide better histologic tissue than marrow stimulation long term results comparable to microfracture in most series include regeneration of autologous tissue, can address larger defects
- limitations
must have full-thickness cartilage margins around the defect
open surgery
2-stage procedure
prolonged protection necessary to allow for maturation
Spontaneous osteonecrosis of the knee(SONK) is an idiopathic condition that leads to the development of ? location?
pathophysiology?
- crescent shaped osteonecrosis lesion, mostly commonly in the epiphysis of the medial femoral condyle
- 99% only 1 jt involved
- may represent subchonral insuffieiency fx, meniscal root tear, post arthroscopy meniscectomy
- acute onset of kneee pain, effusion
- tx;Treatment is generally nonoperative as most cases are self-limiting. Surgical management is indicated for progressive cases that fail conservative management.
- UKA for SONK has demonstrated reliable long-term functional outcomes and is the treatment of choice for severe localized disease.
Progression of osteoarthritis is the most common reason for revision arthroplasty in patients with spontaneous osteonecrosis of the knee (SONK) treated with unicompartmental knee arthroplasty (UKA).
Osgood-Schlatter
-
traction apophysitis of the tibial tubercle
RF? pathophysiology?
tibial tubercle is a secondary ossification center, what are the ages of ossification?
tx and outcomes?
who gets an ossicle excision?
- Bilateral in 20-30%
- Jumpers (basketball volley ball
- stress from extensor mechanism
- cartilage less than 11, 11-14 aphosysis forms, 14-18 apophysis fusions with tibial epiphysis, 18+ fused
- NSAIDS, rest, ice, activity modification, strapping/sleeves to decrease tension on the apophysitis and quadriceps stretching
- 90% have complete resolution
- cast for 6 weeks for severe
- ossicle excision for refractory cases (10% of patients) in skelatally mature patiens w/ persisent symptoms
prognosis: Self-limiting but does not resolve until growth has halted
Sinding-Larsen-Johansson syndrome
- chronic apophysitis or minor avulsion injury of inferior patella pole
- occurs in 10-14yr old children, especially children with cerebral palsy
AIIS avulsion
how does it occur? what attaches there? tx?
- apophyseal avulsion injury seen in adolescent athletes
- eccentric contraction of the rectus femoris (femoral n.) during kicking, males 14-17
- direct head of the rectus femoris
- as hip extends and knee is flexed as hip extends and knee is flexed
- tx: non op, keep hip flexion for 2 weeks lesses stretch of affected rectus and apophysis, guarded WB for 4 weeks
adolescent pelvic apophyseal fractures
ischial tuberosity 50%
AIIS (25%),
ASIS (20%),
superior corner of pubic symphysis (4%)
the iliac crest (1%).
ASIS avulsion
caused by? occurs during? what muscles attach here, what is the innervation?
- caused by sudden and forceful contraction of sartorius and tensor fascia lata
- occurs during** hip extension (sprinting or swinging a baseball bat)**
- tx: rest, protected weight bearing with crutches, and early ROM and stretching
- ORIF if displaced > 3 cm
sartorius (femoral n.)
tensor fascia lata (superior gluteal n.)
meniscal anatomy
best describes bone?
Homeostatic, with elements of osteoid awaiting calcium deposition and resorptive activity from macrophage-like cells
screw-home mechanism which stabilizes the joint is partly a result of:
how does the FCL contribute
Screw-home mechanism
the** larger and more distal medial femoral condyle glides across the medial tibial plateau**, resulting in relative external rotation of the tibia with regard to the femur or internal rotation of the femur by approximately 15° during the last 20° of open-chain (non–weight-bearing) extension. During closed-chain extension, such as during the gait cycle, the femur internally rotates on the planted tibia. The net effect is posteriorly directed translational and rotatory stress restrained by the PCL
FCL: Holds the lateral knee tight during gait relative to the MCL, contributing to the screw-home mechanism of internal femoral rotation. FCL is taut with the knee in extension and relaxes with the knee in approximately 30° of flexion. This tightness of the FCL with the knee in extension contributes to the greater excursion distance of the larger medial femoral condyle during gait extension, resulting in external rotation of the tibia or internal rotation of the femur observed with the screw-home mechanism
sulcus angle, normal vs abnormal why is it important
- A sulcus angle of 138° is normal, whereas a sulcus angle greater than 145° indicates a shallow groove and trochlear dysplasia.
- large trochlear sulcus angle is an important predictor of patellar instability.
- One of the most important considerations in whether to perform trochleoplasty or MPFL reconstruction or both
Meniscus is composed of ?
what maintains its integrity?
The anterior horn of the lateral meniscus (AHLM) overlaps with ?
The posterior horn of the medial meniscus anchored?
force transmission?
- water, proteoglycans, and type I collagen
- Radial collagen fibers help maintain meniscal integrity; circumferential fibers translate joint pressure into circumferential hoop stress
- The anterior horn of the lateral meniscus (AHLM) overlaps with the tibial footprint of ACL.
- The posterior horn of the medial meniscus is anchored posteriorly distal to tibial plateau, augmented by shiny white fibers adjaent to pcl foot print
- medial compartment transmits 50% of joint force, and the lateral compartment transmits 70% of joint force.
Perfusion of menisci decreases from the outer red-red zone; to the middle red-white zone; to the avascular, diffusion-dependent inner white-white zone. Inner zone tears are associated with impaired healing. The shiny white fibers of the posterior horn of the medial meniscus are just anteromedial to the ALB,122 and a shallow bony groove called the medial groove runs along the medial border of the PMB.
The ACL has two bundles, the anteromedial and posterolateral. Which describes their relationship?
The PLB and AMB are parallel in extension
The PCL biomechanics:
primary restraint?
PMB is taught in?
ALB taught in?
Primary restraint against? seoncdary restraint against?
The PCL is the primary restraint against posterior tibial translation of the knee.
PMB taut in extension
ALB taut in flexion
primary restraint against internal rotation and a secondary stabilizer against external rotation from 90° to full extension
bony fabella location?
- Lateral gastrocnemius tendon (LGT) first attaches to bony or cartilaginous fabella.
- sesamoid bone that is variably present in the LGT, may or may not be ossified
- 10% to 30% of the population, with bilateral incidence estimated to be as high as 80%
The posterior oblique ligament:
- POL arises from the distal aspect of the semimembranosus tendon and inserts on the femur approximately 1.4 mm distal and 6.4 mm posterior to the medial gastrocnemius tubercle (rather than to the adductor tubercle, which was commonly thought, from which the POL insertion is 7.7 mm distal and 6.4 mm posterior)
- central arm, has connections to the medial meniscus and the meniscofemoral and meniscotibial portions of the deep MCL (reinforcing the posteromedial joint capsule) and the superficial MCL.
- The central arm acts as the primary attachment to the femur and is an important restraint to internal rotation of the tibia with the knee in extension.
The Iliotibial band relationship to patella
Has an anterior extension to the lateral aspect of the patella
Functions in the knee as a static restraint against internal tibia rotation, ATT during flexion
Changes from extensor to flexor at 30° of flexion
Deep aspect of the ITB attaches to the distal femur via two fibrous bundles known as the proximal and distal Kaplan fibers
Distal attachments
Superficial ITB attaches to the Gerdy tubercle
Deeper capsulo-osseous layer connects the distal femur with the proximal tibia (from the femur just proximal to the LGT to the tibia, posteromedial to the Gerdy tubercle)
Iliopatellar band inserts on the lateral patella and the patellar tendon
The FCL distal insertion can be found most easily:
By entering the biceps femoris bursa.
biceps femoris bursa is an important landmark used to reliably locate the distal attachment point of the FCL. The remnant FCL within the bursa is identified distal to the fibular styloid in patients with an FCL tear and in patients undergoing PLC reconstruction. The proximal FCL usually can be identified via a longitudinal incision in the ITB
The ACL is intraarticular but ?
The ACL is intraarticular but extrasynovial.
Large knee effusion post op after ACL recontruction?
A 22-year-old man reports anterior knee pain, swelling, and is unable to perform a straight leg raise after undergoing endoscopic anterior cruciate ligament (ACL) reconstruction with a bone-patellar tendon-bone autograft 1 week ago. He is afebrile. Examination reveals a clean incision, moderate effusion, a weak isometric quadriceps contraction, active knee range of motion of 5 degrees to 45 degrees, and the patella is ballottable. Knee radiographs show postoperative changes with good femoral and tibial tunnel placements, and normal patellar height. What is the next most appropriate step in management?
get knee aspirate usually post op hemarthrosis, arthrocentesis
Knee pain and swelling in the first week after ACL reconstruction is usually related to a postoperative hemarthrosis. A large hemarthrosis creates capsular distension, which inhibits active quadriceps contraction by a neurologic reflex, the H. reflex. Kennedy and associates reported that an experimentally induced knee effusion at 60 mL was found to result in profound inhibition of reflexly evoked quadriceps contraction. Removal of the hemarthrosis by aspiration will improve strength and often instantaneously restore the ability to contract the quadriceps muscle. A large effusion will also limit knee flexion. EMG and NCVS are not necessary unless there is a high index of suspicion of a femoral neuropathy. Diagnostic ultrasonography is not necessary in this patient but can be useful in the assessment of patellar tendon integrity. MRI is not indicated and would most likely be limited by artifact and postoperative changes. Continuous passive motion is not indicated and would most likely worsen the patient’s symptoms.
ACL + meniscus tear, which side most common in acute and chronic?
A 20-year-old basketball player sustains a knee injury during a game and is seen in the orthopaedic clinic 3 days after injury. Examination reveals a positive Lachman, pivot shift, joint line tenderness, and moderate effusion. Which of the following tissue injuries is most likely causing the jointline tenderness?
The physical examination findings are consistent with an acute anterior cruciate ligament tear. In the acute setting, a lateral meniscus tear is a more common secondary injury than a medial meniscus tear. In one study of acute anterior cruciate ligament tears in alpine skiers, the incidence of lateral meniscus tears was over four times that of medial meniscus tears. Medial meniscus tears are more common in the chronic setting, most likely secondary to its role as a secondary restraint.
highest risk of a future anterior cruciate ligament (ACL) tear?
- Women with a knee valgus moment during landing
- increased dynamic valgus and high abduction loads, were at increased risk of ACL injury
Hewett and associates reported in a study of 205 female athletes that female athletes, with increased dynamic valgus and high abduction loads, were at increased risk of ACL injury. The same investigators in an earlier study of 81 high school basketball players reported that female athletes landed with greater total valgus knee motion and a greater maximum valgus knee angle than male athletes. Female athletes were also found to have significant differences between their dominant and nondominant side in maximum valgus knee angle. Lephart and associates reported that in single-leg landing and forward hop tasks that female athletes had significantly less knee flexion and lower leg internal rotation maximum angular displacement, and less knee flexion time to maximum angular displacement than males. Females with an adduction moment during landing should have a lower incidence of ACL tears. Males in general have a lower incidence of ACL tears.
A patient competing in a professional motocross race sustained a direct blow to the knee after falling off his bike at high speed. He sustained several lacerations as shown in Figure 60. He is able to actively extend his knee painlessly and his Lachman examination is negative. What is the most likely injury and mechanism?
It is important to recognize the injury pattern sustained by this motocross rider by inspection of his traumatic scars present anteriorly over the proximal tibia and the dorsum of the ankle and dorsum of the forefoot, indicating that his foot was in a plantar flexed position with a concomitant blow to the anterior tibia. This is a classic mechanism for a posterior cruciate ligament injury, and external clues (the scars) should not be overlooked when examining the knee. Occasionally, a posterior cruciate ligament injury is overlooked; however, putting together the patient’s history, the examination (especially the posterior drawer and quadriceps active tests) provide a reliable diagnosis. Additional pathology should also be ruled out, such as a posterolateral corner injury and intra-articular pathology. Patella fracture, tibial tubercle avulsion, and patella tendon tears are unlikely because the patient can actively extend the knee. An anterior cruciate ligament tear is unlikely with a negative Lachman examination.
Kinematic testing of patellofemoral motion demonstrates that malalignment that produces increased Q angle causes a shift of the patella laterally in the trochlear groove and is most pronounced during what phase of the flexion arc?
40-90
Dynamic patellofemoral joint contact measurements on cadaveric knees with simulated increased Q angle demonstrated that forces shifted to the lateral facet. The** lateral shift in the patella was most pronounced from 40 to 90 degrees of flexion.** At lower degrees of flexion, the lateral shift was significantly less. At higher degrees of flexion, the continued shift of the patella was not as pronounced.
what is the pathologic motion of a pivot shift exam?
With an ACL-deficient knee in full extension and internal rotation, the lateral tibial plateau subluxates anteriorly. When a valgus load is applied to the knee, the lateral plateau impinges on the lateral femoral condyle. As the knee is flexed, the lateral tibial plateau slides posteriorly into a reduced position, causing an audible clunk. Response 4 correctly describes the pathomechanics that result in the audible clunk heard during the pivot shift maneuver.
A 20-year-old basketball player reports a 6-month history of right groin pain that radiates into his testicles with activities of daily living. He denies any history of trauma. Examination reveals tenderness about the groin, and he has full hip range of motion. The abdomen is soft. Radiographs are normal. Nonsurgical management has consisted of rest and physical therapy, but he continues to have pain. What is the next step in management?
Hernia repair
traditional or classic hernias can be readily detected on physical examination. Diagnostic imaging studies are not helpful and only serve to help exclude other diagnose
Sports hernias may be one of the most common causes of groin pain in athletes. Resisted hip adduction is painful in the case of groin disruption. Radiation of pain into the testicles and/or adductor region is often present. Sports hernias are associated with weakening of the posterior inguinal wall. In contrast with sports hernias, traditional or classic hernias can be readily detected on physical examination. Diagnostic imaging studies are not helpful and only serve to help exclude other diagnoses. Systemic high-dose steroids or sacroiliac joint injections have no role in treatment. High success rates have been reported for laparoscopic hernia repair in athletes.
Discoid Meniscus, Radiographic findings that support your diagnosis would include
radiographs with widening of the lateral joint space up to 11 mm and transverse meniscal diameter >15 mm between free margin and periphery of the meniscal body on coronal views.
Discoid meniscus is a variant found in roughly 3% to 5% of the population. Presentation usually occurs before the age of 10 and is associated with snapping of the knee with palpable fullness to the lateral aspect of the knee. Most occur unilaterally, however bilaterally has been reported to occur roughly 15% to 25%, typically not associated with ligamentous instability. Radiographic findings of discoid meniscus can be seen on both plain radiographs as well as MRI.** Plain radiographs will often show squaring of the lateral femoral condyle with widening up to 11 mm of the lateral joint space.** MRI criteria is based on** transverse meniscal diameter >15 mm between free margin and periphery of the meniscal body on coronal views** and continuity of between the anterior and posterior horns of the meniscus on at least three sagittal cuts.
phenomenon of tumors misdiagnosed as athletic injuries has been termed “sports tumors.”
Exam question: posterior knee pain. Examination reveals soft-tissue fullness and tenderness just above the popliteal fossa, trace knee effusion, full range of knee motion, no instability, and negative meniscal signs. Chronic symptoms. Radiographs normal, whats the most appropriate next step in management?
MRI
Persistent symptoms warrant further diagnostic studies, not additional treatment such as physical therapy, corticosteroid injection, or an unloader brace
The phenomenon of tumors misdiagnosed as athletic injuries has been termed “sports tumors.” Lewis and Reilly presented a series of 36 patients who initially were thought to have a sports-related injury but ultimately were diagnosed with a primary bone tumor, soft-tissue tumor, or tumor-like condition. Muscolo and associates presented a series of 25 tumors that had been previously treated with an intra-articular procedure as a result of a misdiagnosis of an athletic injury. Initial diagnoses included 21 meniscal lesions, one traumatic synovial cyst, one patellofemoral subluxation, one anterior cruciate ligament tear, and one case of nonspecific synovitis. The final diagnoses were a malignant tumor in 14 patients and a benign tumor in 11 patients. The authors noted that oncologic surgical treatment was affected in 15 of the 25 patients. The most frequent causes of erroneous diagnosis were initial poor quality radiographs and an unquestioned original diagnosis despite persistent symptoms. Persistent symptoms warrant further diagnostic studies, not additional treatment such as physical therapy, corticosteroid injection, or an unloader brace. Although a bone scan may be helpful in this case and confirm arthrosis of the medial compartment, the suspicion of a soft-tissue mass makes MRI the imaging modality of choice.
Which of the following findings helps to distinguish between stress fractures of the tibia and shin splints?
With shin splints, a bone scan shows the posterior tibial cortex in a diffuse, longitudinal orientation.
A bone scan showing the tibial cortex in a diffuse, longitudinal orientation is consistent with shin splints compared to a more discreet, localized uptake more commonly seen with a stress fracture.
Anterior tibial pain can often be difficult to diagnose. Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but are also seem in otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient’s history of increased physical activity and on imaging findings. The general symptom of a bone stress injury is stress-related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis. If the diagnosis is made early, most bone stress injuries heal well without complications.
A 40-year-old man who is a manual laborer has had 3 years of worsening medial-sided left knee pain that has inhibited his ability to work. He reports undergoing a left subtotal medial menisectomy 10 years ago. He has been treated with nonsteroidal anti-inflammatory drugs and 2 different corticosteroids, with the most recent injection given 1 month ago. Each injection provided him with a few weeks of pain control. His medical history is unremarkable and he has smoked 20 cigarettes per day for the last 15 years. His body mass index (BMI) is 22. On examination, he has varus alignment of the involved leg and medial joint line tenderness and no lateral or patellofemoral pain. His knee range of motion is 3° shy of full extension to 130° of flexion. He has negative Lachman and posterior drawer test results. He demonstrates no lateral thrust with ambulation.
What imaging study is most appropriate to determine treatment options for this patient? Based on his exam, what should be the next step in management after imaging?
This patient has a classic presentation of postmeniscectomy medial compartment arthritis. The appropriate diagnostic study is weight-bearing radiographs to confirm the diagnosis. An MRI scan will reveal medial compartment arthritis but will not provide information about alignment. A CT scan would be appropriate to detect an occult fracture; however, this condition is not suspected in this clinical scenario. Ultrasonography can provide information about fluid collection around the knee or a deep vein thrombosis; however, these conditions also are not suspected in this clinical scenario.
Because the patient has a correctable deformity (gaps 3 mm with valgus stress), and his symptoms are localized to the involved compartment, a trial of a medial unloader brace is appropriate both diagnostically and therapeutically. If unloading the medial compartment resolves the patient’s symptoms, he would be an excellent candidate for an osteotomy. An MRI scan may be obtained to evaluate ligamentous integrity or to evaluate degenerative involvement of the lateral and patellofemoral compartment for presurgical planning of an osteotomy; however, the integrity of the medial meniscus has no clinical importance in a patient with severe medial compartment arthritis. A repeat corticosteroid injection is not indicated within 1 month of his last injection, and referral to pain management is not appropriate with other options available to help this patient.
A VPHTO is the appropriate intervention considering the patient’s young age, high-functional occupation, examination, radiographic findings, and response to medial unloader bracing. A revision knee arthroscopy would be appropriate for a recurrent medial meniscus tear, but not appropriate in a patient with severe medial compartment arthritis. The patient’s young age and high functional requirements are contraindications to TKA. The presence of severe arthritis is a contraindication to medial meniscus transplant.
The patient is a candidate for a VPHTO. The technical options include a medial opening-wedge or a lateral closing-wedge osteotomy. Both techniques have advantages and disadvantages; however, a medial opening-wedge osteotomy is contraindicated in a smoker because of concern for nonunion. As a result, current smoking history is the only factor listed that would influence the technique used. The history of prior arthroscopy has no relevance in the decision about which type of osteotomy is appropriate. Normal BMI is between 18.5 and 24.9, so this patient’s BMI is considered normal and would not affect the surgical technique (if this patient were obese, a lateral closing-wedge osteotomy would be considered, but this is controversial). His age of 40 years is an indication for HTO but does not influence technique.
Snapping Hip Coxa saltans
What are the 3 causes? What imaging study should you get?
Operative options for each?
External:** IT band sliding over greater troch**; can be seen from across the room. Palpate GT as hip is actively flexed, applying pressure will stop snapping, confirm diagnosis. Obers test: Tightness of tensor fascia
Internal:** iliopsoas tendon** sliding over femoral head, prominent ilipectineal ridge, exotoses of lesser troch, iliopsoas bursa. Reproduced when moving hip from Flexed+ER to Extended + IR position
Intra-articular snapping hip: loose bodies in the hip, synovial chrondromatosis, labral tears.
Dynamic U/S can help visualize abnormal iliopsoas
Tx: PT, CSI if persistent and painful
Excision of GT bursa w/ Z plasty of IT band for painful snapping hip
relase iliopsoas tendon for painful internal snapping hip failed nonop
hip scope and removal of loose bodies or labral debridment repair if intra-articular pathology.
Obers test hip: limited adduction when hip held in extension
Ober test
Ober test is positive with contracture of the tensor fascia lata or iliotibial band which limits adduction of the hip while in an extended position
A 21-year-old professional ballet dancer reports a painful popping sensation over her right hip joint. Examination reveals that symptoms are reproduced with hip flexion and external rotation. Which of the following studies will best confirm the diagnosis? Wht’s the treatment?
It is caused by the iliopsoas tendon gliding over the iliopectineal line or the femoral head
Snapping is reproduced by hip flexion and extension or flexion with external rotation and abduction.
**Conventional and dynamic ultrasonography will confirm the snapping structure. **
iliopsoas tendon is located lateral to the iliopectineal eminence when the hip is in full flexion, and may “snap” medially as the hip is extended back to neutral position
Hamstring injury
most common site of rupture in adults? Skeletally immature?
risk factors?
Muscles/innervation?
Sciatic nerve distance form origin?
Non-op vs op:
PrP injection?
Adults: myotendinous junction
Skeletally immature: avulsion of ischial tuberosity
RF: previous hamstring injury (increases risk of reinjury by factor of 6
SM,ST, Long head of Biceps: tibia branch of sciatic
Short head of biceps: common peroneal
**sciatic nerve is 1.2 cm from lateral bony aspect of hamstring origin **
Nonop: most; single tendon tears, 2 tendon , 2cm retraction, rupture at myotendinous junction, 6 weeks to healing, return when 90% strength
Tendon repair: proximal avulsions, partial avulsions failed 6 months of non-op, 2 tendons w/ >2cm retractinon, 3 tendon tears
High level athlete, give PrP w/in 48 hrs
Hip flexion, knee extension: eccentric contraction of hamstring at the end of swing phase when muscle fibers are at maximal elongation.
Hamstring injury prevention
**Nordic hamstring exercise: **
shown to reduce injuries by 50-70% in some studies
isolated targeting of hamstrings
long head of the biceps femoris and semimembranosus are more active during hip extension
semitendinosus and short head of biceps femoris more active during knee flexion
athlete kneels while heels are held on ground by an assistant; the athlete than leans forward until he is prone and then returns to original upright position
Hamstring tendon repair:
incision? whats at risk?
transverse incision over gluteal crease
sciatic nerve runs on average 1.2 cm lateral to the most lateral aspect of ischial tuberosity
vertical fascial incision will often lead to encountering a hematoma or fluid collection
Treatment algorithm for hamstring ruptures
Untreated partial hamstring ruptures may present with residual pain, weakness and hamstring dysfunction. The mechanism is eccentric lengthening (sprinting or cutting) A proposed treatment algorithm is: (1) Nonoperative management for single tendon avulsion with <2cm retraction. The ruptured tendon scars to intact tendons. (2) Repair for acute 3-tendon rupture (semitendinosus, semimembranosus, biceps femoris) with retraction >= 2cm. (3) Surgery for young (<50y) patients with 2 tendon avulsion and retraction >= 2cm.
Quad contusion
MRI if concern for extensor mechanism.
- Direct blow to thigh
- immobilization, cryotherapy, NSAIDs, physical therapy
- 120 degrees of flexion using an ace wrap or hinged knee brace immediately after injury for 24-48 hours, frequent use of cold therapy
- myositis ossificans seen in chronic cases, 9-18% of cases. resection only for mature lesions w/o signs of continued growth. Maturation at 6-12 months.
Femoral neck stress fractures
What imaging?
Who’s at higher risk?
Non-op tx for?
Operative tx for?
MRI
Female athlete triad:
2-4x increased risk.
dysregulation of HPG axis, decreased estrogen levels=no osteoblast maturation, increased osteoclast activity relative to OB activity
FAI: 50% of FNF, 42% CAM, 78% pincer
Nonoperative treatment is indicated for compression sided fractures with < 50% femoral neck width.
Cannulated screw fixation is indicated for tension sided stress fractures or compression sided fractures with > 50% width or hip effusion
- repetitive loading of femoral neck exceeds elastic properties of bone causing microscopic fracture
- continuous microscopic fractures exceed osteoblastic activity resulting in stress fracture
- 3x risk with absent calcitonin receptor C allele, vitD receptor C-A halotype
Femoral neck stress fractures biomechanics
BW across femoral neck with jogging/running?
Compressive vs tension sided fxs?
Jogging 3-5x/Running 8.4x
Compressive= inferior femoral neck, microfracture propogates 45 degrees more stable oblique pattern
Tension sided fx: bending forces of superior lateral neck stabilized by abductor forces, when abd fatigue fracture propogates at 90 deg, unstable transverse pattern
Nonoperative treatment is indicated for compression sided fractures with < 50% femoral neck width. Cannulated screw fixation is indicated for tension sided stress fractures or compression sided fractures with > 50% width or hip effusion
Femoral neck stress fractures imaging
Xray early vs late findings?
- early: 90% initial, and 50% of repeat 4- 6 weeks normal
- 6-8 weeks, grey cortex sign, lineral lucency, endosteal callous, scleortic line traversing trabeculae
Femoral neck stress fractures imaging
What to look for on MRI
Hip effusion is associated with?
- periosteal or bone marrow edema on STIR or fat-suppressed T2
- line of decrease of intensity on T1 coronal corresponding with signal on T2 and STIR
- hip fusion: 8x higher risk of propagation
Compression-sided fractures are usually treated non-operatively, with protected weight-bearing until pain-free, and cessation of running until healed. Tension-sided fractures and fractures that involve more than 50% of the femoral neck are generally treated operatively with percutaneous screw placement.
Bone scan: not necessary anymore, uptake due to increased metabolic activity secondary to bone remodeling
Tibia Stress Fx
most common in? physical exam findings?
imaging?
Work up?
When to operate?
Highest likely hood of non-union
- athletes and military recruits, especially after a change in type, intensity, or duration of an activity.
- limp or abnormal weight-bearing, with focal tenderness and a positive one-legged hop test
- Xrays: Will be normal 2-3+ weeks. Cortical thickening will show up after several weeks.
MRI: treatment of choice, high sensitivity and specificity.
○ Bone marrow edema: T2 weighted stress reaction, precursor to stress fx
○ Linear areas of low signal intensity: T1 weighted image, indicative of fx - Tx: activity modification, eval of vitD, osteoporosis/penia, female triad. Eval by endo.
- IMN, for fx of anterior cortex, “dreaded black line” load sharing with an intramedullary tibial nail has been used to decrease the risk of delayed or nonunion of this tension-sided fracture.
- fractures of anterior cortex of tibia have highest likelihood of delayed healing or non-union
Tc-99m bone scan: increased uptake, less specific than MRI
tibia is the most frequent stress fracture location in most series in both athletes and modern military training. The anterior midshaft region of the tibia may be at higher risk secondary to tensile forces and a relative paucity of blood supply.
Stinger: definition?
most common symptoms?
Cuased by 3 types of mechanisms?
When to get a MRI/who are you worried about?
- transient brachial plexus neuropraxia
- unilateral tingling in arm w/ transient weakness in C5, 6 m (deltoid, biceps), resolution 1-2 mins, + spurling
- traction, compression, or direct blow (see below)
MRI for Bilateral symptoms, multiple stingers, reccuring symptoms
- traction: downward displacement of arm+bedning of neck away from side of injury
- compression, lateral head turning towards affected side
- direct blow to erbs point superior to clavicle
- Cervical spine hyperextension with or without concomitant lateral flexion is thought to compress or pinch the nerve root in the neuroforamen, thereby causing transient symptoms. It is generally accepted that the athlete may return to immediate play if complete symptomatic resolution is achieved with full motor strength and full painless cervical range of motion. However, if the player has two or more stingers in one game, it is recommended that he or she be withheld from the current sporting contest and re-revaluated at the end of the game
Neck injuries in athletes
- Spear tackling
- What associate conditions put athletes at risk?
- How to exam on the field (NATA guidelines)
- what to look for on c-spine xray?
- Who gets an MRI?
- Spearing: #1 mechanism of neck injury, can lead to gradual cervical stenosis and loss of cervical lordosis. Axial loading of subaxial spine occurs with this type of tackling
- previous c-spine trauma, cervical stenosis, congenital os hypoplasia, os odontoideum, klippel feil anomolies
- Stablize head/neck, log roll supine, remove facemask, remove helmet and shoulder pads if done safely
- MRI if xray shows torg <.8 and or bilateral symptoms
- presence of congenital stenosis (i.e., a Torg ratio < 0.80) does not preclude a player from returning to play in the absence of clinical, symptomatic instability.
- canal diameter of < 13mm (normal is17mm)
- Torg-Pavlo ratio (canal/vertebral body width) of < 0.8 (normal is 1.0
- congenital stenosis (Torg-Pavlov ratio <0.8) without instability (but patients should be counseled regarding the risks
- incidence of spinal stenosis (using a Torg ratio of 0.8 as a definition) to be 49% in asymptomatic professional football players
Figure 1 is the MRI scan of a 15-year-old boy who has had knee pain with running for 5 months. What is the most appropriate treatment?
Arthroscopic or open reduction and internal fixation
OCD is an acquired lesion of the subchondral bone. Patients with OCD initially report nonspecific pain and variable amounts of swelling. Initial radiographs help identify the lesion and establish the status of the physes. An MRI scan is useful for assessing the potential for the lesion to heal with nonsurgical treatment. Nonsurgical treatment is appropriate for small, stable lesions in patients with open physes and focuses on activity restriction for 3 to 9 months. Surgical treatment is necessary for unstable or detached lesions. Stable lesions with intact articular cartilage can be treated with subchondral drilling to stimulate vascular ingrowth, with radiographic healing at an average of 4.4 months. Fixation is indicated for unstable or hinged lesions, and stabilization of the fragment can be achieved using a variety of implants through an arthroscopic or open approach. The fragment should be salvaged and the normal articular surface restored whenever possible.
locked knee that cannot be fully extended
mechanical block of a bucket-handle tear that has flipped into the notch. Also, the pain may be so severe that the muscle spasm prevents the knee from straightening out. When the patient is anesthetized, the muscle spasm relaxes and the meniscus can be reduced out of the notch. Arthroscopy is the treatment of choice. A meniscal repair is usually possible in large bucket-handle tears because the meniscus is torn in the red-red zone where most of the vascular supply is located. If the handle portion is badly frayed or damaged, a partial meniscectomy should be performed. The classic finding on MRI is a “double PCL sign.” This is due to the flipped portion of the meniscus in the notch.
A loose body is encountered during a left knee arthroscopy in the posterolateral compartment. In the arthroscopic photograph shown in Figure 1, the posterior aspect of the lateral femoral condyle is shown on the right and the posterolateral capsule is shown on the left. The arthroscope is placed in what anatomic interval to visualize this loose body?
The arthroscopic photo shows a grasper removing a loose body from the posterolateral compartment through an accessory posterolateral portal. The blunt arthroscopic trocar is placed through the intercondylar notch in the direction of the posterior horn of the lateral meniscus. The trocar passes between the ACL and the posterior aspect of the lateral femoral condyle into the posterolateral compartment.
What is the primary function of the structure at the tip of the probe in Figure 1?
Popliteus: dynamic internal rotator of the tibia
The structure shown in the figure is the popliteus tendon. This structure is a continuation of the popliteus muscle belly and attaches more proximally through its hiatus in the lateral meniscus onto the lateral femoral epicondyle anterior and distal to the insertion of the lateral collateral ligament. The popliteus is a dynamic internal rotator of the tibia. The popliteus complex reinforces the posterior third of the lateral capsule and plays a major role in the dynamic and static stabilization of the lateral tibia on the femur, including restriction of external tibial rotation, posterior tibial translation, and varus rotation of the tibia.
arthroscopic view of the intercondylar notch of a right knee from an anterolateral portal. What is the main function of the structure delineated by the black asterisks? After injury to the structure as indicated by the asterisks, which examination test most likely will demonstrate an abnormal finding?
posterolateral bundle of the anterior cruciate ligament (ACL). This bundle is optimally positioned in the knee to resist rotatory forces during terminal knee extension. PL bundle is tightest in flexion
“Resist anterior translation during knee flexion” best describes the anteromedial bundle.
Anterior cruciate ligament (ACL) injuries are notorious for blunt cartilage injuries and bone bruising. Typical bone bruising patterns in ACL injuries include the
middle third of the lateral femoral condyle and the posterior third of the lateral tibial plateau
most common location for osteochondritis dissecans?
Wilson test to detect potential OCD lesion?
posterolateral aspect of the medial femoral condyle.
Internally rotate the tibia while extending the knee from 90° to 30°.
Positive if pain is present with internal rotation and extension that is relieved with external rotation
Mixed evidence exists on the efficacy of arthroscopic drilling for stable symptomatic OCD lesions in skeletally immature patients or for stable lesions that did not healed after a 3-month trial of nonsurgical management. Consensus exists that surgical treatment be offered to symptomatic skeletally immature and mature patients with salvageable unstable or displaced OCD lesions.
Inconclusive evidence exits regarding surgical technique.
unstable osteochondral lesion of the medial femoral condyle.
OCA transplantation indicated for? What else needs to be addressed? Why would ACI be bad for this lesion depicted in the MRI?
MR images clearly show deep subchondral bone involvement.
primary treatment of large cartilage lesions, osteochondral lesions, and salvage procedure from failed prior cartilage surgery.
Correction of mechanical axis malalignment, ligamentous insufficiency, and meniscal deficiency should also be addressed.
ACI alone or an arthroscopic microfracture procedure would not address the bone defect, leaving an uneven articular surface.
MR images clearly show deep subchondral bone involvement.
Figure 1 is the radiograph of a 50-year old woman with lateral-sided left knee pain. She noticed the pain over the last few months and has had no new injury. She had a microfracture performed of her lateral femoral condyle 5 years ago. What is the likely cause of the finding noted on her radiograph?
Removal of the subchondral plate
realignment osteotomies:
medial compartment osteoarthritis?
lateral compartment osteoarthritis?
**Valgus-producing osteotomy for medial compartment osteoarthritis. ** Medial opening wedge high tibial osteotomy (HTO) is commonly used to manage medial knee osteoarthritis in patients with varus malalignment. or lateral closing wedge HTO
Varus-producing osteotomy for lateral compartment osteoarthritis, Distal femur osteotomy (DFO). The goal is to relieve lateral compartment pain and slow the progression of osteoarthritis by shifting the mechanical axis into neutral or slight varus, which can be achieved via lateral opening wedge or medial closing wedge DFO.
In patients with isolated medial compartment osteoarthritis, valgus-producing osteotomies are a well-proven surgical treatment option. Figure 2 AP full-length weight-bearing radiographs of bilateral lower extremities of a patient. A, Preoperative radiograph demonstrates the mechanical axis through the medial compartment. B, Radiograph obtained after high tibial osteotomy demonstrates that the mechanical axis has been shifted to the downslope of the lateral tibial spine.
what osteotomy do you perform for a lateral compartment OA?
Varus-producing osteotomy for lateral compartment osteoarthritis, Distal femur osteotomy (DFO). The goal is to relieve lateral compartment pain and slow the progression of osteoarthritis by shifting the mechanical axis into neutral or slight varus, which can be achieved via lateral opening wedge or medial closing wedge DFO.
Illustrations of knees show posterior tibial slope correction based on plate shape and positioning. A, Medial placement of a plate with a rectangular wedge should not alter the slope. B, In an anterior cruciate ligament–deficient knee, posteromedial placement of a rectangular wedge plate or a tapered wedge plate results in decreased slope and reduced anterior tibial translation. C, In a posterior cruciate ligament–deficient knee, anteromedial placement of a rectangular wedge plate results in increased slope and reduced posterior tibial translation.
A 60-year-old patient had the procedure shown in Figure 1 performed 5 years ago. When converting this patient to a total knee arthroplasty (TKA), what patellar problem is commonly encountered intraoperatively?
Patella baja is commonly encountered when converting a high tibial osteotomy (HTO) to a TKA. Patella baja most likely occurs because of scarring. Meding and associates study did not show an increased rate of lateral release when converting a knee that had undergone a previous HTO.
Whats
Figure 1 shows the AP radiograph of a patient who underwent a previous upper tibial osteotomy (UTO). The patient may be at risk for which of the following during total knee arthroplasty (TKA)?
Instability
results of TKA for patients with a prior UTO are reported to be slightly suboptimal. The major problems are patella baja, difficulty in exposure, and instability. Most of the patients exhibit some degree of instability prior to TKA, and ligamentous balancing may be difficult. Ligamentous structures are at risk of rupture during the difficult exposure. The problem of ligamentous balancing is exacerbated by the change in the joint slope that can occur after UTO.
Figures 1 and 2 are the AP and lateral radiographs of a 32-year-old man 10 years after anterior cruciate ligament (ACL) reconstruction. The patient now has worsening medial knee pain and a failed ACL with instability. What is the best surgical option?
Closing wedge and slope neutralizing high-tibial osteotomy
young patient with isolated lateral compartment OA, surgery?
distal femoral varus osteotomy.
- medial closing/lateral opening wedge supracondylar femoral osteotomy
The long-term outcome of a distal femoral varus osteotomy has been quite favorable and should remain the primary choice for this young active woman. Sharma and associates have shown that a 5-degree valgus malalignment has a five-fold chance of progressing at least one grade within 18 months, making a corrective osteotomy the most important surgical maneuver.
mpfl reconstruction
Figure 1 is the MRI scan of a patient with recurrent knee instability, which persists after a period of nonsurgical treatment. Anatomic reconstruction of the torn ligament is recommended. What radiographic finding is the most important independent predictor of recurrent instability following surgery?
What is a possible complication of tunnel positioning with MPFL reconstruction being too distal?
Trochlear dysplasia
Tightness in extension
Tunnel malpositioning with MPFL reconstruction
Too proximal: laxity in extension, tightness in flexion, resulting in anterior knee pain and failure
Too distal: tightness in extension, resulting in extensor lag or inability to fully extend
Popliteus
attachment? role?
What is the anatomic relationship of the popliteus insertion of the femur relative to the lateral collateral ligament origin?
- continuation of the popliteus muscle belly
- attaches more proximally through its hiatus in the lateral meniscus onto the **lateral femoral epicondyle anterior and distal to the insertion of the lateral collateral ligament. **
- Deep, Anterior, Distal
- dynamic internal rotator of the tibia
- popliteus complex reinforces the posterior third of the lateral capsule and plays a major role in the dynamic and static stabilization of the lateral tibia on the femur, including restriction of external tibial rotation, posterior tibial translation, and varus rotation of the tibia.
where is the origin of popliteofibular ligament?
Myotendinous junction of the popliteus tendon
postoperative radiograph of a patient who underwent an anterior cruciate ligament (ACL) reconstruction (with bone-patella tendon-bone autograft) that failed. He initially had loss of flexion postoperatively. What is the most likely cause of this failure?
Anterior placement of the femoral tunnel.
The key to this question is the fact that the patient initially lost flexion postoperatively and this relates to anterior placement of the femoral tunnel, thus capturing the knee. The bone plug seen on the radiograph is actually from the tibial tunnel, but this occurred as the patient forced flexion until failure of the ACL graft and pullout of the plug from the tunnel. Although it could be argued that better tibial fixation would have prevented this failure, poor placement of the femoral tunnel led to the failure of this ACL reconstruction
autograft options for acl.
In comparing various autograft options, numerous considerations should be discussed with patients. BTB is associated with less creep and a slightly lower re-rupture rate compared with hamstring autograft, with no substantial difference in graft survival compared to quadriceps autograft. Reported complications of BTB include increased rates of anterior knee pain and slightly higher risk of osteoarthritis. Hamstring autograft is associated with less donor site morbidity compared and a lower midterm and long-term incidence of osteoarthritis compared with BTB; however, it is associated with a longer time to biologic incorporation, weakness with hip extension and terminal knee flexion, and variable lengths and sizes during harvesting. Lastly, quadriceps autograft has gained popularity because of its increased relative graft thickness, availability of a bone block, and higher ultimate load to failure and stiffness compared with BTB. A potential for anterior knee pain and a risk of knee flexion stiffness and quadriceps strength deficiency exist. Prospective, randomized comparison studies on hamstring versus BTB have revealed consistently good subjective outcomes and objective stability.17 Substantial improvement in patient-reported outcomes has been noted with each type of graft.18 A cohort study comparing quadriceps tendon autograft and hamstring autograft favored quadriceps tendon autograft without increased morbidity.19
Graft Selection
Higher failure rate with allografts compared with autografts
Higher failure rate with hamstring tendon autografts compared with bone-patellar tendon-bone and quadriceps tendon autografts
More articular cartilage deterioration with allografts compared with autografts
Poorer patient-reported outcomes with allografts compared with autografts
Longer time to return to sports activity with allografts compared with autografts2-5
Which of the following physical examination findings is most likely present in the condition producing the MRI findings shown in Figure 1?
Pivot shift, ACL tear. Bone bruise pattern Lateral femoral condyle and tibial plateau
The T2-weighted sagittal MRI scan shows the classic “bone bruise” pattern seen with an anterior cruciate ligament (ACL) tear. These lesions are thought to represent subcortical trabecular hemorrhages and are manifested as an increase in signal intensity on T2-weighted images and diminished signal intensity on T1-weighted images. They are classically located in the mid-portion of the lateral femoral condyle and posterior aspect of the lateral tibial plateau. This is due to the fact that an ACL tear typically is the result of a valgus-external rotation of the femur on the fixed tibia. This places most of the weight-bearing stress on the lateral femoral condyle, which rotates laterally and impacts the posterior lip of the lateral tibial plateau. This may result in an impaction fracture if the force is great enough, but more frequently causes merely a microfracture of the involved subcortical trabeculae.
tibial tunnel placement
The desired anatomic anterior-posterior and medial-lateral center of the tibial ACL tunnel is located at approximately 43% of the sagittal diameter (measured from anterior) and 47% of the coronal diameter (measured from medial) of the tibial plateau, respectively. The angulation of the tibial tunnel should be oriented according to the inclination of the roof of the intercondylar notch. A tibial tunnel that is placed too anteriorly and misplacement in the medial-lateral orientation are associated with graft impingement. A tibial tunnel that is placed too posteriorly leads to a vertical graft orientation with insufficient restoration of rotatory knee laxity
Sagittal, T2-weighted, fast-spin echo fat-suppression MRI of the knee of a patient who underwent anterior cruciate ligament reconstruction shows tibial tunnel malpositioning, which is too posterior at 54% of the anteroposterior distance (not the recommended 43%), leading to a vertical anterior cruciate ligament graft
What is wrong with this tunnel placement? Assuming graft failure and appropriate new positioning, what would you expect to improve on exam? anterior drawer vs pivot shift?
Too vertical of femoral tunnel. Pivot shift. The postsurgical images reveal a much more anatomic position of the femoral tunnel that should provide better rotational control of the knee, thereby improving the pivot shift (compared to the vertical femoral tunnel).
what is wrong with this positioning?
anterior and vertical placement of his femoral tunnel, which has been shown to cause stiffness in knee flexion.
Technical failure is the most common reason for ACL reconstruction failure. Tunnel position is the most frequent cause of technical failure. Malpositioning of the tunnel affects the length of the graft, causing either decreased range of motion or increased graft laxity. This patient has anterior and vertical placement of his femoral tunnel, which has been shown to cause stiffness in knee flexion. Although graft choice is an important factor when planning ACL reconstruction, overall outcomes with autograft tissues are fairly similar. Fixation of the graft at the femoral or tibial end is not as important as tunnel position. Fixing the graft in flexion can cause extension loss when isometry is not achieved, but this condition is not touched upon in this scenario.
Figures 1 and 2 are the radiographs of a 21-year-old football player who underwent anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft 1 year ago. He reports mild stiffness in his knee. Upon examination, he has a negative Lachman test, trace effusion, and range of motion from 0 to 85ø of knee flexion.
