Knee Flashcards
Merchant view radiograph measurements (2 angles)
Sulcus angle: measured by the lines of the highest peaks in the medial and lateral femoral condyle. Normal angle is 138° +-6°
Congruency angle (patellar tilt): patellar position in the trochlear groove. if the patella ridgeline falls medial to midpoint of sulcus angle value is negative, if the line falls lateral value is positive. normal is -6°. positive 16° maybe associated with the patellar subluxation
Knee Varus versus valgus angle measures
Genu valgum angle greater than 185°
Genu Varum angle less than 175°
Anatomical axis: 185 degrees
Vascularlization of the meniscus
Red zone: peripheral third of meniscus
Red white zone: middle third of meniscus
White zone: central third of meniscus
Posterior lateral corner of lateral meniscus separated from capsule by popliteus tendon, therefore a vascular.
Vascularlization of the meniscus
Red zone: peripheral third of meniscus
Red white zone: middle third of meniscus
White zone: central third of meniscus
Posterior lateral corner of lateral meniscus separated from capsule by popliteus tendon, therefore a vascular
NOTE: posterolateral meniscus supported by poplitues and will not heal independently.
Lateral meniscus connect Chin’s
- Transverse Ligament: to medial meniscus anteriorly
- Patellomeniscal LIgament: to patella anteriorly
- Posteriorly to popliteus muscle and PCL
- meniscofemoral ligament to medial femoral condyle (*Is taut with IR)
Medial meniscus connections
- Transverse ligament: to lateral meniscus anteriorly
- Patelomeniscal ligament: to patella anteriorly
- Posteriorly to semimembranosus muscle
- Connections to PCL and ACL and posterior and anterior horn’s respectively
Meniscus mobility
- Medial meniscus less mobile than lateral which contributes to a higher incidence of injury.
- Muscular contractions of semimembranosus in popliteus muscle can create movement in medial and lateral meniscus respectively
- -Menisci innervated by proprioceptors and nociceptors
Lateral compartment of knee (three main regions)
One: anterior region
– Supported by lateral retinaculum
Two: middle third
– Supported by iliotibial band
Three: posterior third
–supported by arcuate complex (LCL)
**Flabella w/in LCL present in 15-30% of patients
**Muscular attachments to PL complex: b.femoris and popliteus
**Minimal assist from ITB and JC to support LCL
MCL superficial and deep layer function
Superficial layer: primary function to restrain valgus stress
Deep function: meniscal support and control restraint to anterior translation
MCL and LCL most stressed in what position
25-30° knee flexion
MCL superficial and deep layer function
Superficial layer: primary function to restrain valgus stress
Deep function: meniscal support and control restraint to anterior translation
**MCL insertion distal to pes anserine
58% valgus restrain in extension (5 deg flexion)
78% valgus restrain in flexion (25 deg flexion)
**Attachment of MCL to semimembranosus and VM allows for dynamic response of ligament of muscular forces
Oblique popliteal ligament
Reinforces posterior medial knee joint capsule obliquely on a lateral to medial diagonal
Tendinius expansion of semimembranosus muscle
Posterior oblique ligament
Reinforce his posterior medial knee joint capsule obliquely on the medial to lateral diagonal
ACL bundles and function
-Larger posterolateral bundle: taut 0-20 deg flexion (i.e. Lachman’s test)
Valgus stress on ACL
Increased throughout flexion on both bands when MCL is unable to support medial side of knee
PCL bundles function
Anterior lateral bundle tight in flexion primary restrain to posterior translation from 40 to 120°
Posterior medial bundle tight in extension primary restraint to posterior translation after 120
Minimal to no restraint to posterior translation at near extension therefore reliance upon MCL and posterior capsule is increased
PCL bundles function
Anterolateral bundle (95% of substance): tight in flexion primary restrain to posterior translation from 40 to 120°
Posterior medial bundle (5% substance) tight in extension primary restraint to posterior translation after 120
- Minimal/no restraint to posterior translation at near extension: reliance on MCL and posterior capsule is increased
- clinically greatest posterior translation at 70-90 deg knee flexion due to slacking of all other supports at this angle (MCL, poplieus, JC): optimal angle to assess PCL integrity
Knee flexor to joint muscles
Primary: Hamstrings
Secondary: popliteus gastrocnemius sartorial gracillis, tensor facia latae
Muscles creating a Varus moment in knee
Semimembranosus, semitendinosis, medial head of gastrocnemius sartorial and gracilis
(other way to think of it: provide valgus restraint)
Patellafemmoral quadriceps vectors
Vastis lateralis 35°, vastus medialis
Unable to preferentially contract VMO over vastus medialis
Muscles creating a valgus moment at the knee
Biceps femoris lateral head of gastrocnemius and
popliteus
(Other way to think of it: provide varus restraint)
Degrees of knee flexion and patellofemoral contact areas
20°: inferior small
45°: middle (both med and lat sides)medium
90°: superior 1/3 large
135° medial and lateral greater on lateral side and on odd facet
Percent of adult knees with plica and locations
30% have medial plica (can be painful)
-infrapatellar are most common plica though rarely painful
Functional activities enforces through patellofemoral joint
Walking: 50% body weight
Running: five times bodyweight
Rising from chair: 6.7 times bodyweight
Q – angle definition and norms
Represents Structural relationship between quadriceps muscle in the patella (ASIS to patellar midpoint)
Men 10 to 15°
women 15 to 20°
Angles greater than 20° considered abnormal
Ottawa rules for knee
1: age greater than 55
2: isolated tenderness of the patella
3: tenderness at the fibular head
4: inability to flex knee to 90°
5: inability to bear weight both immediately and in the emergency room ( four steps limping is okay)
Best positions to avoid Patellafemmoral compressive forces
-Avoid terminal < 30° knee extension during non-weight-bearing exercise (due to decreased contact)
–>SLR has decreased patellar force than with quad activation with increased knee flexion BUT decreased patellar stability so if unstable train at greater degrees knee flexion
-Avoid 90° flexion or greater in weight-bearing activity
(Due to decreased contact force and increased quad activation)
Immediate joint swelling versus delayed joint swelling
- -Immediate swelling indicates internal trauma and hemiarthrosis
- -Delayed onset of hours or days indicate synovial fluid response, often to joint surface strain (patellar dislocation, MCL injury)
Knee stress testing grading scale
Grade 1+ equals 3 mm to 5 mm
Grade 2+ equals 5 mm to 10 mm
Grade 3+ equals greater than 10 mm
Differential diagnosis slipped capital femoral epiphysis and legg calve perthes syndrome
SCFE – overweight or very tall and thin prepubescent male 7-18 yo; reproduce knee pain with FABER; loss of hip IR and excessive ER
LCPD 5 to 18-year-old; associated with (+) knee exam of swelling, gradual onset pain and locking
Collateral ligament integrity tests
Performed at zero and 20 to 30° knee flexion
Valgus stress test at full extension determines possible or probable involvement of MCL along with secondary restraints
– Grade 2+ PCL may be involved ACL usually involve
– Grade 3+ ACL probably involved
Varus stress test at full extension determines possible involvement of LCL ACL and PCL
Varus sensitivity .25
Valgus sensitivity .86-.96
Specificity unknown
ACL tests
- Anterior drawer – tests anteromedial bundle
– ACL rupture if excursion is greater than 6 mm with soft or and feel
– Increased excursion with tibial IR may indicate compromise of lateral capsule/PCL
– increased excursion with external rotation May indicate MCL, posterior capsule, or posterior oblique ligament involvement
-Sensitivity 76%/ specificity 86% - Lachman test-posterolateral (larger) bundle: gold standard
– Sensitivity 96% specificity 100%
Pivot shift: guarding often an issue
- sensitivity 24% specificity 98%
PCL tests
Posterior drawer –
– If increased laxity with tibial ER indicates possible posterior lateral corner injury
– Sensitivity 89% specificity 92%
Posterior sag sign – performed at 45° hip flexion 90° knee flexion
– Sensitivity to 78% specificity 100%
–Activate Quads in this position: reduction is 97.6% sensitive and 100% specific for PCL rupture
Meniscus tests
Unlikely to be confirmed with clinical examination unless patient experiences an acute locking episode
McMurray test – attempt to elicit locking or clicking complaints
– Sensitivity 58.5% and 16%
– Specificity 93.4% and 98%
Aptly test –pain with distraction indicates ligamentous injury, pain with compression indicates meniscal injury
– Medial meniscus 81%
– Lateral meniscus 90%
Joint line tenderness low sensitivity and specificity
Combination of all three tests sensitivity 78.8% specificity 79.3%
Meniscus tests
Unlikely to be confirmed with clinical examination unless patient experiences an acute locking episode
McMurray test – attempt to elicit locking or clicking complaints (IR tibia for lateral men, ER for medial men)
– Sensitivity 58.5% and 16% (LOW)
– Specificity 93.4% and 98%
Aptly test –pain with distraction indicates ligamentous injury, pain with compression indicates meniscal injury
– Medial meniscus 81%
– Lateral meniscus 90%
Joint line tenderness low sensitivity and specificity
Combination of all three tests sensitivity 78.8% specificity 79.3%
Meniscal pathology composite score
one: history of catching or locking
two: joint line tenderness
three: pain with forced hyperextension
Four: pain with maximal passive flexion
Five: pain or an audible click with McMurray
5/5= 92.3% +PV Specificity: 99%
4/5 specificity 96%
Ankle position during seated passive knee extension
Plantarflexion is ideal to decrease the gastrocnemius moment arm
Patellofemoral tests
- pain with MMT through quadriceps ROM
- Step down test – says visual analog scale and range of motion
- But tell him ability – normal between 25 and 50% of the teller with, greater movement suggest laxity (Sage sign)WHAT?!
- Apprehension test – excessive movement and patient expression of concern
- Patellar tilt test – flexion to 20° attempts to flip lateral edge of the patella upward, if unable to do so indicates type lateral retinaculum
Drop-out casts
Used in cases of recalcitrant knee extension limitations
Loose-pack position of knee
20 to 30° flexion
Quadriceps strength deficit % that indicates use of NMES
15-20%
Benefits of eccentric muscle training
Effect greater changes and neural activation and increase muscle hypertrophy
Improve volitional concentric contraction
Decrease symptoms of tendinitis
Jumpers knee eccentric exercise dosage and benefits
Three repetitions, two times per day, seven days per week for 12 weeks
More beneficial than concentric exercises
Use of a decline board if there is discomfort
Should refrain from sport activity during rehabilitation
Bilateral eccentric training may be as effective as unilateral training
Patellar taping application medial versus lateral
Apply in one direction and assess. if greater than 50% symptom reduction is not achieved in tape in alternate direction
ACL Coper criteria and screen
criteria: patient must meet ALL criteria to be considered
Isolated ACL tear, full pain-free range of motion, NO joint effusion, MVIC quadriceps 70% of uninvolved LE, single leg hopping on involved leg with out pain
* administered within two months of injury
*If 5/5 met, then trial 10 tx PT; patients must then meet all criteria to be D/C’d w/o referral back to surgeon
Screen:
- Episodes of getting way since initial injury: <1
- Hop test:greater than 80% timed
- KOS ADL: greater than 80%
- Global rating score: greater than 60%
If positive administer perturbation activities
Unloading brace function and application
Treatment of pain relief for unicompartmental degenerative joint disease in tibiofemoral joint
Minimal to no pain relief and an obese patient patients
No evidence to support the sloughing reversal of degenerative process with the use of these unloading braces
ACL bracing
No conclusive evidence demonstrates effectiveness of bracing in preventing injuries
Decrease in rx of braces s/p reconstruction, no evidence.
Use of brace 1 to 2 years post operatively correlated with significant decrease in quadriceps strength compared to bracing for three months.
Increased function where your brace in patients with 80% quadriceps strength
Unclear whether brace wearing is cause or effect to quadriceps strength
Notchplasty
Surgical technique were bone his resected from intercondylar notch using a motorized a abrader which allows for increased base in joint
ACL repair
Presurgical considerations prior to ACL reconstruction
Full knee extension and resolution of inflammatory process minimize the risk of limited postsurgical knee range of motion
Two most important measures to improve during ACL rehabilitation
Quadriceps strength and full knee extension
Inability to achieve these is strongly correlated with decreased postoperative function
Hamstring strength appears to recover without focused intervention even when this muscle group is used the source of the graft
Rationale for open chain quadricep exercises status post ACL reconstruction
Wayberry (WB) exercises were not sufficient to restore quadriceps strength.
ACL strain appears to be the highest 30° with knee extension
PROM 0-120 deg = no strain on ACL
Graft strongest day of implant, decreases in strength consistently (healing doesn’t become a factor until 4-6 wks s/p; graft weakest 12 weeks post op
Management of ACL reconstruction and coexisting pathology
Meniscal repair: no WB flexion past 45 deg 0-4 weeks post op
Chondral damage – weight-bearing cannot be restricted long enough to allow full healing of articular surfaces without compromising ACL health, restrict WB 0-4 weeks, may benefit from bracing afterward
memisectomy: no changes needed
MCL injury – ACL reconstruction provide stable environment for healing even great three MCL sprain, therefore MCL is typically not surgical repaired, place LE in IR to decrease stress on MCL
PCL – rehabilitation is focused on PCL guidelines because of risk of PCL graft failure risk
Indications of complex regional pain syndrome and
Failure to progress, complains of instability, decreased function, increased pain/ swelling, disproportionate pain to injury
ACL reconstruction revision surgery
That is often less rigid after construction revision then typically soon
Revision surgeries are often staged
Where activities and exercise must be slow down protect already compromised graft
PWB 2 weeks, still gait trainig to encourage full knee extension; defer FWB in uncontrolled environment until 4 weeks s/p
Management of ACL tear in skeletally immature population
Initially managed conservatively allowing growth plates to close
Decision to return to sport is often based on risk-benefit analysis
If surgery is indicated there are surgical options that are designed to avoid damage to epiphyseal plate
Female athletes and risk for ACL injury and prevention of if
Females are 4-8 times more likely to tear ACL than males
Injuries are out the noncontact as result of a cutting rotary motion
reasons are inward collapse of knee, muscular weakness, straight knee when landing, excessive quadriceps activation eccentric activity, joint laxity, narrow femmoral notch and hormonal influences
Exercise regimens implemented to help prevent ACL injuries have shown a decease risk for ACL injuries by 88-74%
PCL nonsurgical management
We’re coming because often has partial tears in injuries to the PCL higher rate of feeling when compared to ACL
quadricep strength and return to function
Early medial compartment to generation can be associated with media meniscus and/or PLC involvement
decreased meniscal force and increased TF force due to altered arthrokinematics
increased PF force (esp with OKC exercises)
Surgical management of PCL tear
Often indicated with continent and injuries of meniscus capsule or other ligaments
Single bundle Achilles tendon all allograft
High percentage of patients with continued laxity after surgery. some evidence suggests decrease laxity with double bundle procedure
Double bundle patellar tendon and semi tendinosis allograft
Rehabilitation initially slow progression especially inflection
Graft is most tension between 70-90° of flexion
Limited resistance of knee flexion (hamstrings) for four months
Minimal P Cialis year from 60° to 0 nonweightbearing knee extension
Bottom Line: SLOW knee flexion and ROM gains
- knee flexion to 60 at 2 weeks
- knee flexion to 110 at weeks 3-5
- full knee ROM at 16 weeks
- Tension at graft greatest at 70-90 degrees flexion so train knee extension at 60-0deg flexion (greater deg found to have posterior shear force with OKC knee extension)
- NO resisted knee flexion until 8 weeks (due to post shear of hamstrings)
Considerations with collateral ligament rehabilitation
Injured ligaments should be protected from stress during initial 6-8 weeks of healing
Internal rotation of the tibia will decrease MCL stress extra rotation of tibia decrease LCL stress
Normalizing quadriceps strength in facilitating dynamic stabilization are the focus
Grade 3 strain space repair can be braced or immobilize and 30° flexion during wb first 2-6 weeks
MCL often treated conservatively; surgery vs conservative tx = results
–NOTE: MCL injury in children, suspect epiphyseal injury vs MCL due to fairly of bone vs ligament
LCL: mixed nonop results
Arthritis definition
Degeneration of articular cartilage, inflammation of the synovium, and changes in the underlying subchondral bone to the point where patients are typically debilitated by pain and resultant loss in function
Meniscal injury rehab considerations
Nonoperative treatment:
–if injury is localized to the peripheral third
– Primary focus controlling swelling worse during passive range of motion and minimizing quadrate step strength losses with nonweightbearing activity
– Patient education to avoid squatting pivoting cutting and running to minimize stress
Decision to remove/repair based on meniscus tear location (peripheral 1/3 repair esp in younger patients)
-Meniscectomy – recovery time to six weeks
-Repair – WB slowly progressed for 8 weeks, if stable fixation and good vascularization then gait with knee locked in extension allowed WBAT for 4-6 weeks; week 1-4: no WB flexion past 45 deg
4-8 wks: no WB flexion past 90
recovery time 6 to 9 months
Sport activities: 4 months after longitudinal repair, 6-9 months after radial and central 1-3 repair
Meniscal transplant:
–recovery time 6 to 9 months
– age under 40, high activity level, minimal osteoarthritis, not a candidate for TKA
-Limit WB 3-6 weeks s/p; FWB achieved 6-9 weeks s/p
Quadriceps strength and knee arthritis
Reported to be the strongest single predictor of functional limitations in patients with knee arthritis
Preoperative quadriceps strength is predictive of functional ability one year after TKA
hyaluronic acid injections
Found to lubricate join and decrease swelling and inflammation by inhibiting induction inactivity of degenerative enzymes in proinflammatory signals
Oral Chondroprotective agents
Current recommendation for a glucosamine sulfate and chondroitin can be used but discontinued after six months of no benefit has occurred