Overview Knee examination History Physical ACL Usually non-contact Landed awkwardly Felt "pop" Immediate swelling Lachman positive Pivot shift positive Large hemarthrosis PCL Stuck dashboard Fall with PF foot Posterior pain Posterior sag sign Posterior drawer (at 90° flexion) Quad active test MCL Blow to outside of knee Medial pain Valgus instability LCL Varus injury Lateral pain Varus instability PLC Lateral and posterior pain Usually combined with other ligament injuries Dial test positive(at 30° flexion) Meniscus Mechanical symptoms (catching, locking) Pain at joint line Delayed swelling Joint line tenderness McMurray positive Patella Fall with DF foot May feel 2 "pops" Swelling Anterior pain Pain with stairs Patellar apprehension Tender over MPFL Effusion Patellar crepitus Pain with active compression test Increased Q-angle Inspection Skin scars trauma erythema Swelling Muscle atrophy normal quadriceps circumference 10 cm (VMO) 15 cm (quadriceps) Asymmetry Gait antalgia stride length muscle weakness Standing limb alignment neutral, varus, valgus Palpation Joint line tenderness Tenderness over soft tissue structures pes anserine bursae patellar tendon iliotibial band Point of maximal tenderness Effusion patella balloting milking Range of Motion (patient supine) Active and passive flexion/extension normal range 10° extension (recurvatum) to 130° flexion rotation varies with flexion in full extension, there is minimal rotation at 90° flexion, 45° ER and 30° IR abduction/adduction in full extension, essentially 0° at 30° flexion, a few degrees of passive motion possible Neurovascular Exam Sensation medial thigh - obturator anterior thigh - femoral posterolateral calf - sciatic dorsal foot - peroneal plantar foot - tibial Motor thigh adduction - obturator knee extension - femoral knee flexion - sciatic toe extension - peroneal toe flexion - tibial Vascular pulses popliteal dorsalis pedis posterior tibial ankle-brachial index ABI < 0.9 is abnormal ACL Injury Large hemarthrosis Quadriceps avoidance gait (does not actively extend knee) Lachman's test most sensitive exam test grading A= firm endpoint, B= no endpoint Grade 1: <5 mm translation Grade 2 A/B: 5-10mm translation Grade 3 A/B: >10mm translation PCL tear may give "false" Lachman due to posterior subluxation Pivot shift extension to flexion: reduces at 20-30° of flexion patient must be completely relaxed (easier to elicit under anesthesia) mimics the actual giving way event KT-1000 useful to quantify anterior laxity measured with knee in slight flexion and 10-30° externally rotation PCL Injury 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 Posterior drawer (at 90° flexion) with the knee at 90° of flexion, a posteriorly directed force is applied to the proximal tibia and posterior tibial translation is quantified the medial tibial plateau of a normal knee at rest is ~1 cm anterior to the medial femoral condyle most accurate maneuver for diagnosing PCL injury Quadriceps active test attempt to extend a knee flexed at 90° to elicit quadriceps contraction positive if anterior reduction of the tibia occurs relative to the femur MCL Injury Valgus instability = medial opening 30° only - isolated MCL 0° and 30° - combined MCL and ACL and/or PCL classification Grade I: 0-5 mm opening Grade II: 6-10 mm opening Grade III: 11-15 mm opening Anterior Drawer with tibia in external rotation grade III MCL tears often associated with ACL and posteriomedial corner tears postive test will indicate associated ligamentous injury LCL Injury Varus instability = lateral opening 30° only - isolated LCL 0° and 30° - combined LCL and ACL and/or PCL Varus opening and increased external tibial rotatory instability at 30° - combined LCL and posterolateral corner PLC Injury Gait varus thrust or hyperextension thrust Varus stress test varus laxity at 0° indicates both LCL & cruciate (ACL or PCL) injury varus laxity at 30° indicates LCL injury Dial test > 10° ER asymmetry at 30° only consistent with isolated PLC injury > 10° ER asymmetry at 30° & 90° consistent with PLC and PCL injury Posterolateral drawer test performed with the hip flexed 45°, knee flexed 80°, and foot ER 15° a combined posterior drawer and ER force is applied to the knee to assess for an increase in posterolateral translation (lateral tibia externally rotates relative to lateral femoral condyle) Reversed pivot shift test with the knee positioned at 90°, ER and valgus forces are applied to tibia as the knee is extended, the tibia reduces with a palpable clunk tibia reduces from a posterior subluxed position at ~20° of flexion to a reduced position in full extension (reduction force from IT band transitioning from a flexor to an extensor of the knee) External rotation recurvatum test positive when the leg falls into ER and recurvatum when the lower extremity is suspended by the toes in a supine patient Peroneal nerve assessment injury present with altered sensation to foot dorsum and weak ankle dorsiflexion Meniscus Injury Joint line tenderness Effusion McMurray's test flex the knee and place a hand on medial side of knee, externally rotate the leg and bring the knee into extension a palpable pop or click is a positive test and can correlate with a medial meniscus tear Patella Pathology Large hemarthrosis absence of swelling supports ligamentous laxity and habitual dislocation mechanism Medial-sided tenderness (over MPFL) Increase in passive patellar translation measured in quadrants of translation (midline of patella is considered "0") and should be compared to contralateral side normal motion is <2 quadrants of patellar translation lateral translation of medial border of patella to lateral edge of trochlear groove is considered "2" quadrants and is an abnormal amount of translation Patellar apprehension Increased Q angle J sign excessive lateral translation in extension which "pops" into groove as the patella engages the trochlea early in flexion associated with patella alta