Meniscus Instability The menisci are C-shaped discs of fibrocartilage that are interposed between the condyles of the femur and tibia. Primary function is load transmission or weight bearing. Secondary function is shock absorption during gait. Contribute to joint stability and lubrication.
Meniscus Instability Nerve endings provide proprioceptive feedback for joint position. A tear or loss of the menisci, either partial or complete, hinders their ability to perform. A twisting injury to the knee with the foot in weight bearing can injure the menisci. The outer 20% is vascular – peripheral injuries may heal.
Meniscus Instability Clinical Signs and Symptoms Local medial or lateral joint pain Limited knee range of motion Crepitus upon movement Joint effusion Knee buckling Pain on walking up and down stairs Pain on squatting
Apley’s Compression Test Procedure: Patient prone. Flex leg to 90 degrees. Grasp the patient’s ankle and apply downward pressure while you internally and externally rotate the leg. Positive Test: Flexing the knee distorts the meniscus. Downward pressure further stresses the meniscus. Pain or crepitus on either side indicates a meniscus injury on that side.
Apley’s Compression Test
McMurray’s Test Procedure: Patient supine. Flex leg. Externally rotate the leg as you extend. Internally rotate the leg as you extend. Positive Test: Flexion and extension distort the meniscus. Adding external and internal rotation further distorts the meniscus. A palpable or audible click indicates injury of the meniscus.
Ligamentous Instability The major ligaments of the knee are the anterior and posterior cruciate and the medial and lateral collateral ligaments. Ligament injuries are among the most serious knee disorders. Usually due to traumatic stress to the knee while bearing weight.
Ligamentous Instability Valgus stress may sprain or tear the medial collateral ligament. Varus stress may sprain or tear the lateral collateral ligament. Both of these stresses with a rotational force may sprain or tear the anterior and/or posterior cruciate ligaments.
Ligamentous Instability Clinical Signs and Symptoms Knee pain Limited range of motion Difficulty in weight bearing Joint effusion Knee giving out; chronic unstable knee
Drawer Sign Procedure: Patient supine. Flex the leg and place the foot on the table. Grasp behind the knee and pull and push on the leg. Hamstring tendons must be relaxed. Positive Test:
More than 5 mm of tibial movement on the femur when leg is pulled - injury or tear to one or more of the following structures is indicated: Anterior cruciate ligament Posterolateral capsule Posteromedial capsule Medial collateral ligament (more than 1cm movement) Iliotibial band Posterior oblique ligament Arcuate-popliteus complex
If excessive movement occurs when the leg is pushed, an injury to one or more of the following structures in indicated: Posterior cruciate ligament Arcuate-popliteus complex Posterior oblique ligament Anterior cruciate ligament
Lachman’s Test Procedure: Patient supine. Knee 30° flexion. Grasp thigh with one hand to stabilize. Grasp tibia with opposite hand and pull forward. Positive Test: Softened feel or anterior translation of the tibia suggests a possible tear of: Anterior cruciate ligament Posterior oblique ligament
Reverse Lachman’s Test Procedure: Patient prone. Flex leg to 30°. Stabilize posterior thigh with one hand. Push tibia posterior with the other hand. Positive Test: Posterior pressure on the tibia stresses the posterior cruciate ligament. A soft end feel and posterior translation of the tibia are positive findings.
Reverse Lachman’s Test
Apley’s Distraction Test Procedure: Patient prone. Flex leg to 90°. Stabilize patient’s thigh with your knee. Pull on the ankle while internally and externally rotating the leg. Positive Test: Distraction of the knee takes pressure off the meniscus and puts strain on the medial and lateral collateral ligaments (non-specific).
Apley’s Distraction Test
Adduction Stress Test Procedure: Patient supine. Stabilize medial thigh. Grasp lower leg and push medially. Positive Test: Excessive movement of the tibia away from the femur indicates a possible tear of: Tibial collateral ligament Posterior meniscofemoral ligament Posterior medial capsule Anterior cruciate ligament Posterior cruciate ligament
Abduction Stress Test Procedure: Patient supine. Stabilize lateral thigh. Grasp lower leg and pull it laterally. Positive Test: Excessive movement of the tibia away from the femur indicates a possible tear of: Fibular collateral logaments Posterolateral capsule Posterior cruciate ligament Anterior cruciate ligament
Abduction Stress Test
Medial & Lateral Stability Rating Scale Grade 0No joint Opening Grade 1+Less than 0.5 cm joint opening Grade to 1.0 cm joint opening Grade 3+More than 1cm joint opening
Patellofemoral Dysfunction The patella protects the anterior aspect of the knee. It acts as a fulcrum that increases the mechanical advantage of the quadriceps. The patella lies in the trochlear groove. With normal flexion and extension it tracks smoothly in the groove.
Patellofemoral Dysfunction Many causes of anterior knee pain involve abnormal tracking of the patella or direct trauma to the patella. Patellofemoral injuries include fractures, dislocations, malalignment syndrome, chondromalacia patellae, and patellofemoral arthritis.
Patella Grinding Test Procedure: Patient supine. Move patella medially and laterally while pressing down. Positive Test: Pain under the patella - chondromalacia patellae, retropatellar arthritis, or a chondral fracture. Pain on the patella – osteochondritis. Pain over the patella – prepatellar bursitis.
Patella Grinding Test
Patella Apprehension Test Procedure: Patient supine. Manually displace the patella laterally. Positive Test: A look of apprehension on the patient’s face and a contraction of the quadriceps muscle indicates a chronic tendency to lateral patella dislocation. Pain is also present with this test.
Patella Apprehension Test
Knee Joint Effusion Effusion in and around the knee may be caused by trauma, infection, degenerative joint disease, rheumatoid arthritis, gout, or pseudogout. The fluid may contain blood, fat, lymphocytes, and crystals such as urate, pyrophosphate, and oxalate.
Knee Joint Effusion Clinical Signs and Symptoms Knee pain on walking Anterior knee inflammation Knee joint warmth to touch
Patella Ballottement Test Procedure: With one hand, encircle and press down on the superior aspect of the patella. With the other hand, push the patella against the femur with your finger. Positive Test: If fluid is present in the knee, the patella will elevate when pressure is applied. When the patella is pushed down, it will strike the femur with a tap.