Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 41-06: Musculoskeletal Injuries of the Knee + Key Features Download Section PDF Listen +++ ++ Effusion can occur with intra-articular pathology, such as osteoarthritis, and meniscus and cruciate ligament tears Acute knee swelling (due to hemarthrosis) within 2 hours may indicate ligament injuries or patellar dislocation or fracture Table 41–5 shows the differential diagnosis of knee pain Table 41–6 outlines possible diagnoses based on the location of pain ++Table Graphic Jump LocationTable 41–5.Differential diagnosis of knee pain.View Table||Download (.pdf) Table 41–5. Differential diagnosis of knee pain. Mechanical dysfunction or disruption Internal derangement of the knee: injury to the menisci or ligaments Degenerative changes caused by osteoarthritis Dynamic dysfunction or misalignment of the patella Fracture as a result of trauma Intra-articular inflammation or increased pressure Internal derangement of the knee: injury to the menisci or ligaments Inflammation or infection of the knee joint Ruptured popliteal (Baker) cyst Peri-articular inflammation Internal derangement of the knee: injury to the menisci or ligaments Prepatellar or anserine bursitis Ligamentous sprain ++Table Graphic Jump LocationTable 41–6.Location of common causes of knee pain.View Table||Download (.pdf) Table 41–6. Location of common causes of knee pain. Medial knee pain Medial compartment osteoarthritis Medial collateral ligament strain Medial meniscal injury Anserine bursitis (pain over the proximal medial tibial plateau) Anterior knee pain Patellofemoral syndrome (often bilateral) Osteoarthritis Prepatellar bursitis (associated with swelling anterior to the patella) “Jumper’s knee” (pain at the inferior pole of the patella) Septic arthritis Gout or other inflammatory disorder Lateral knee pain Lateral meniscal injury Iliotibial band syndrome (pain superficially along the distal iliotibial band near lateral femoral condyle or lateral tibial insertion) Lateral collateral ligament sprain (rare) Posterior knee pain Popliteal (Baker) cyst Osteoarthritis Meniscal tears Hamstring or calf tendinopathy + Clinical Findings Download Section PDF Listen +++ ++ Evaluation should begin with general questions about duration and rapidity of symptom onset and the mechanism of injury or aggravating symptoms Overuse or degenerative problems can occur with stress or compression from sports, hobbies, or occupation A history of trauma as well as history of orthopedic problems requiring surgery should also be elicited Symptoms of infection (fever, recent bacterial infections, risk factors for sexually transmitted infections [such as Neisseria gonorrhea] or other bacterial infections [such as Staphylococcus aureus]) should always be evaluated Common symptomatic complaints Presence of grinding, clicking, or popping with bending may be indicative of osteoarthritis or the patellofemoral syndrome "Locking" or "catching" when walking suggests an internal derangement such as meniscal injury or a loose body in the knee Intra-articular swelling of the knee or an effusion indicates an internal derangement or a synovial pathology. Large swelling may cause a popliteal (Baker) cyst. Acute swelling within minutes to hours suggests a hemarthrosis, most likely due to an anterior cruciate ligament injury, fracture or patellar dislocation, especially if trauma is involved Lateral "snapping" with flexion and extension of the knee may indicate inflammation of the iliotibial band Pain that is worsened with bending and walking downstairs suggests issues with the patellofemoral joint, such as chondromalacia of the patella or osteoarthritis Pain that occurs when rising after prolonged sitting suggests a problem with tracking of the patella A careful history, coupled with a physical examination that includes observation, palpation, and range of motion testing, as well as specific tests for particular anatomic structures is frequently sufficient to establish a diagnosis Swelling in the hollow or dimple around the patella and distention of the suprapatellar space may indicate knee joint effusion + Diagnosis Download Section PDF Listen +++ ++ Laboratory testing of aspirated joint fluid, when indicated, can lead to a definitive diagnosis in most patients Plain (weight-bearing) radiographs and MRI used most commonly However, CT and ultrasound are sometimes useful An acute hemarthrosis represents bloody swelling that usually occurs within the first 1–2 hours following trauma + Treatment Download Section PDF Listen +++ ++ See treatment of specific disorders Patellofemoral Pain Meniscus Injury Posterior Cruciate Ligament (PCL) Injury Collateral Ligament Injury Anterior Cruciate Ligament (ACL) Injury