Lachman test
With the knee slightly bent, the examiner assesses forward translation of the shin bone relative to the thigh bone to evaluate the anterior cruciate ligament.
Knee assessment typically begins with a history of onset, mechanism of injury if applicable, and pain location, followed by observation of swelling, alignment, and active range of motion.
A battery of special tests then helps assess ligament stability, meniscus integrity, and patellofemoral mechanics, guiding whether further imaging or referral is warranted.
Assessment tests
McMurray test
Combining knee rotation with bending and straightening while palpating the joint line can reproduce clicking or pain associated with a meniscus tear.
Patellar grind (compression) test
Gently compressing the kneecap against the thigh bone during a slight contraction can reproduce pain typical of patellofemoral pain syndrome.
Valgus and varus stress tests
Applying gentle sideways stress to the knee at slight bending evaluates the integrity of the inner and outer collateral ligaments.
Functional single-leg squat
Observing alignment and control during a single-leg squat helps identify movement patterns, such as excessive inward knee collapse, relevant to several overuse conditions.
Red flags
These warrant prompt clinical review rather than unsupervised exercise progression.
Inability to bear weight after injury
A sudden inability to bear weight following a twisting or impact injury raises concern for fracture or significant ligament injury and warrants urgent evaluation.
Locked knee
An inability to fully bend or straighten the knee, often due to a displaced meniscus fragment or loose body, typically requires prompt evaluation.
Significant, rapid swelling after injury
Marked swelling developing within hours of an injury can indicate a significant internal injury such as a ligament tear and warrants assessment.
Signs of infection
Warmth, redness, and fever around the knee raise concern for septic arthritis, a medical emergency requiring urgent care.
This combination of history, special tests, and functional assessment allows clinicians to distinguish between the knee's many possible sources of pain and determine whether imaging or specialist referral is warranted.
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