Look at the patient - note if patient pyrexial or unwell. Measure weight and BMI.
Look at the patient's gait - note any limp.
Look at the joint - note joint swelling and deformity (valgus/varus).
Look at the muscles - note muscle wasting or contracture and compare sides.
Examine for an effusion using patellar tap and the massage (bulge) test.
Feel for site(s) of tenderness including the patellofemoral joint, medial and lateral joint including MCL and LCL.
Examine the popliteal fossa - note sites of tenderness, Baker's cyst, or vascular abnormality.
Assess range of movement (active and passive and compare both knees):
Knee flexion normally 3 to 140 degrees (115 degrees required for most activities of daily living).
Feel for crepitus with a hand on the knee cap.
Note fixed flexion deformity.
Note clicks or grinding on movement.
Examine the knee ligaments for laxity:
MCL and LCL - look for adduction and abduction movement with knee flexed to 30 degrees.
ACL - Anterior Drawer test (pull tibia forward when sitting on the patient's foot with patient prone with knee flexed to 90 degrees), Lachman's test (pull/push tibia forward and push/pull thigh backward with knee flexed to 15 to 20 degrees), and Pivot Shift test (best done by Orthopaedic surgeon).
PCL - Posterior Drawer test (as for Anterior Drawer test but push tibia backwards), Posterior Sag test (observe knees with patient prone and knees flexed to 90 degrees. Look for posterior sag).
Vascular examination of lower limb.
Patellar apprehension test (apply pressure to medial patella when patient prone with knee extended - then, flex the knee to 30 degrees and note lateral patella movement and any patient apprehension).
Knee joint aspiration if there is an effusion.
Examine the patient's hips, ankles and lumbar spine. Note evidence of OA elsewhere and any referred pain.