Knee - Fx, Dislocation, Patellorfemoral Joint Flashcards
Meniscus
- describe
- semi-lunar cartilage
- fibrocartilagenous disks
- aid in shock absorption and load distribution in knee during motion
- articulate with tibia
- concave in shape, thin to free medial edge
Meniscal injuries
- common cause
- combo of loading/shearing force on meniscus during rotation
- Mostly in young/healthy patient
- may be chronic
Meniscal injury in elderly often dt what
often atraumatic
- as simple as rising from seated position or stooping over to reach something on low shelf
Three zones of meniscal injury and description
- Red/Red: outer 1/3, plentiful blood supply from capsular margin of meniscus
- Red/White: middle 1/3, diminished vasculature, less capacity to heal
- White/white: completely avascular inner 1/3 (won’t heal)
Why is it important to know the meniscal zones?
- location dictates treatment
where are the majority of symptomatic meniscal tears?
inner 2/3 - where low/no capacity to heal
Meniscal tear presentation
- catching, locking, popping sensations
- one-sided knee pain (all medial or all lateral)
- effusion over 12-24 hours (slower than ACL/PCL)
Classic meniscal tear case
twisting injury playing basketball, small amt swelling the next day, now pain on stairs and catching sensation
Meniscal tear
- PE
- impingement causes pain at terminal ends of motion (flexion and extension)
- medial/lateral joint line pain at 90 degrees flexion
Meniscal tear
- special tests
- Apley’s (compression or distraction)
- McMurray’s (GS)
- Deep Squat/Duck walk: if can perform, unlikely have tear
What does McMurray’s actually test
compression with varus/valgus stress and terminal flexion/extension
**low sensitivity and specificity… difficult to reproduce pain…
Mensical tear
- imaging
XR
- weight-bearing
- AP and lateral minimum
- Specialty: bilateral with notch view
MRI
- GS (second only to diagnostic arthroscopy)
Who is a candidate for meniscal tear conservative tx
- Pt has well-tolerated sx
- no deficit in PROM (no locking)
- no medical co-morbiidities
Meniscal tear conservative treatment
- RICE
- oral NSAIDs
- intra-articular steroid injection
- activity modification
- bracing not effective other than effusion control
Who is a candidate for surgical tx for meniscal tear
- Sx affect ADL or athletics
- bucket-handle tear that blocks ROM
- lrg tear in repairable zone
Surgical tx of meniscal tear - three types
- partial menisectomy
- meniscal repair
- trephination
Tibial plateau fracture
- describe
- fx of tibial condyles just below joint line of knee
- generally above or includes tibial tubercle
Tibial plateau fracture
- locations
- 60% lateral condyle
- 15% medial condyle
- 25% bicondylar
Tibial plateau fracture
- Exam
- R/O compartment sx
- evaluate ligaments for injury
- test peroneal nerve function (foot drop)
Tibial plateau fracture
- Imaging
XR
- AP and lateral min
- oblique and bilateral comparison helpful
- CT if intra-articular depression or comminution (3D reconstruction!)
Tibial plateau fracture non-operative management
- describe fracture
- describe
- non-displaced or minimally displaced with stable knee on exam
- immobilization brace
- NWB
- referral
- early ROM
Tibial plateau fracture operative tx
- describe fracture
- majority
- displaced wedge
- condylar widening
- depression of articular surface **
- gross comminution
Patella fracture
- MC dt what
- majority: direct trauma to patella (fall or blow)
- also forceful contraction of quads, usually = avulsion fx of quad tendon or patellar tendon at distal patellar pole
Patella fracture
- presentation
- severe anterior knee pain
- knee held in full extension with little to no ROM
- large effusion
- ecchymosis and potentially low leg edema
- usually unable to bear weight
Patella fracture
- imaging
XR
- 3 view of knee (AP, lateral, oblique)
- sunrise if possible
- bilateral helpful
- CT with 3D reconstruction if possible
- MRI might be helpful if no CT/pt can remain still
Patellar fracture types
Direct trauma
- comminution common
- articular cartilage damage
Indirect trauma
- less comminution
- transverse fx
Displacement of patellar fractures
- 2 descriptions
- any incongruence of articular surface >2mm
2. greater than 3mm separation of fragments
Patellar fractures nonoperative treatment
- when appropriate
- tx options
If non-displaced and extensor mechanism is intact and can actively straight leg raise
- aspirate tense hemarthrosis
- knee immobilizer brace x 4-6 wks
- slow, progressive ROM with PT after 4-6 weeks
- quad strengthening
Patellar fractures operative treatment
- when appropriate
- Extensor mechanism is disrupted
- Displacement of transverse fx
- displacement or comminution or articular step-off
- compromised skin overlying patella dt trauma
Knee dislocation
- what joint
- tibia-femoral articulation NOT patello-femoral :)
Knee dislocation
- how dangerous?
- limb-threatening injury
- time is of the essence!
- laceration of popliteal artery/vein possible
(not common)
Knee dislocation
- extent of injury
- generally multi-ligament injury d/t high E trauma
- often both ACL and PCL
- either MCL or LCL
Patellar subluxation/dislocation
- describe
Traumatic subluxation/dislocation of patella out of femoral trochlea
Patellar subluxation/dislocation
- what must happen for this to occur?
One of the stabilizing structures must fail:
- medial patellofemoral ligament (MPFL)
- medial retinaculum
- chondral surfaces
Patellar subluxation/dislocation
- common in what population
- adolescents
- F>M (probably due to skinnier trochlear space, easier for patella to get out)
Patellar subluxation/dislocation
- MC medial or lateral?
lateral!! unless crazy blunt trauma
Patellar subluxation/dislocation
- what anatomic variances predispose
- hypoplastic femoral trochlea
- Patella alta
- lateralized tibial tubercle
Patellar subluxation/dislocation
- presentation of acute dislocation
- gross deformity
- empty trochlea
- patella lateral
- often in flexed knee position
Patellar subluxation/dislocation
- presentation of subluxation or reduced dislocation
- large effusion
- medicalized knee pain
- painful PROM
- quad inhibition
Patellar subluxation/dislocation
- reduction technique
- pressure applied to patella in medial direction
- knee brought passively into extension
- reduce ASAP
Patellar subluxation/dislocation
- special test
- apprehension test: similar to shoulder
Patellar subluxation/dislocation
- Imaging
- AP and lateral XR w/comparison views
- Sunrise/Rosenburg is vital
Patellar subluxation/dislocation
- Conservative tx requirements
- no lateral tilt on sunrise
- no lateralization on AP
- no loose body
Patellar subluxation/dislocation
- conservative tx
- brace in full extension
- WBAT on crutches
- PT for quad strength after 4-6 weeks immobile
- patellar stabilizer for activity
Patellar subluxation/dislocation
- sx requirements
- chronic
- failed conservative
- loose body on XR from MPFL avulsion
Patellar tendon rupture
- describe
- MC population
- failure of extensor mech d/t excessive loading and/or unhealthy soft tissue (+/- quadriceps tendon rupture)
- middle-aged (rec basketball league player)
Patellar tendon rupture classic case
48 yo male w/ acute pain and inability o perform straight-leg raise after jumping injury
Patellar tendon rupture
- presentation
- difficulty with full weight bearing and ambulation d/t loss of extensor mechanism
- sig soft tissue edema and ecchymosis
Patellar tendon rupture
- exam findings
- Inability to perform straight leg raise
- palpable/visible defect in normally firm contour of quads or patellar tendon
Patellar tendon rupture
- workup
- AP and lateral XR - patellar misalignment
- MRI: helpful if partial rupture
- often a simple clinical dx
Patellar tendon rupture
- tx
- referral for sx consult
- require soft tissue repair to restore extensor mechanism
Osgood-Schlatter’s Dz
- describe
- Traction apophysis in the adolescent at the insertion of the patellar tendon onto the tibial tubercle
- Tibial tubercle has its own ossification center, which maybe disrupted
- D/t rapid change in height in osseous centers w/o compensatory lengthening in the extensor mechanism or overuse/over demand is placed on immature skeleton
Osgood-Schlatter’s Dz
- presentation
- painful anterior knee in adolescent (MC male)
- inflammation and calcification at tubercle = characteristic prominent tubercle
- able to straight leg raise
- often atraumatic, usually overuse/chronic
- unable to kneel on affected side dt pain
Osgood-Schlatter’s Dz
- workup
- clinical dx
- XR often unnecessary unless traumatic injury present or very acute sx
- avulsion/fragmentation of apophysis do not gen need intervention
Osgood-Schlatter’s Dz
- Treatment
- reassurance is self-limiting
- sx can last 1-2 yrs during height of growth
- activity modification: avoid some activities or completely cease athletics
- RICE, mild analgesics
- patellar tendon straps
Osgood-Schlatter’s Dz
- indications for sx tx
- non-union or fibrous union of apophysis after skeletal maturity
- pain refractory to tx
Chondromalacia patella
- describe
- softening and fissuring of articular cartilage on post surface of patella
- MC adolescent/young female
- dt misalignment of patella in trochlea (anatomic variance, increased Q-angle, quad weakness)
Chondromalacia patella
- classic case
- 16 yo track and field female has slow onset anterior knee pain over 3-4 months. No injury, occasional swelling, “grating sensation behind knee cap”
Chondromalacia patella
- Presentation
- *diff ascending stairs and walking down decline
- chronic anterior knee pain
- insidious onset
- “grinding” or “grating” sensation behind patella
Chondromalacia patella
- exam findigns
- patellofemoral crepitus with PROM
- crepitus increases with AROM
- painful squatting/duck walk like meniscal tear but no joint line pain
- no TTP of patellar tendon
Chondromalacia patella
- imaging
Usually not helpful, may indicate alignment problems:
- Patella alta
- Patella baja
- lateralization of patellar tracking
Chondromalacia patella
- conservative tx
- exhaust PT (months??)
- activity mods
- NSAIDs and analgesics
- bracing
Chondromalacia patella
- sx tx
- pts recalcitrant to conservative
- shaving chondroplasty of articular surface
- patellar realignment
Plica syndrome
- presentation
- location
- presents like medial meniscal tear (mechanical sounds and catching)
- clean MRI and fail weeks of conservative tx
- almost always medial
Plica syndrome
- describe
- redundant strap of medial synovial membrane that rubs upon joint movement
- not an injury
Plica syndrome
- tx
- steroid shots: if work, even for a minute or two, know problem is intraarticular
OA of knee
- must distinguish between…
- 3 locations
- primary vs. secondary
- medial, lateral, patellofemoral
OA of knee
- how to take images
- always weight bearing!
OA of knee
- post-traumatic causes
- post-surgical changes
- non-operative management of ligamentous injury (don’t tx ACL injury)
- fracture-related
OA of knee
- Tx
- NSAIDs
- Injections: corticosteroids, hyaluronic acid
- PT
- Brace
- Activity mods
- Sx - arthorplasty
PEARLS
- always compare bilaterally
- effusion (hips?) never lies = intra-articular pathology
- ACL = acute injury, effusion, hear/feel pop
- HISTORY
