Examination starts with a general examination of the knee followed by specific examination to confirm a specific diagnosis that has been indicated by the history. The history and examination should lead to a management plan that may involve further targeted investigations.
General examination includes assessing the patient standing, walking and lying supine, and includes active, passive and provocative tests or movements. This should allow specific examination to concentrate on one of fours areas:
- The patello-femoral joint and extensor mechanism
- Meniscal pathology
- Ligament stability
a. Standing and walking
This includes general habitus, leg alignment, posture, change in alignment on walking, the presence of an antalgic hip gait and muscle wasting. Looking at the leg starts as the patient walks in to the clinic and takes in to account their general demeanour, appearance, manner of walking and mobility around the examination area. All these factors add information to the diagnostic equation.
In normally aligned legs, with the patellae pointing forwards, the knee and ankles should be gently touching together.
Varus (bowlegged) or valgus (knock-kneed) alignment is noted and the presence of increasing deformity as a lateral or medial thrust on walking is also checked for.
Mal-alignment may also be rotational. In normally aligned legs when the patella points forward then the feet should also point forward, nearly in parallel. There is clearly a wide range of what is normal and mild varus or hyperextension, for example, may be a physiological variant of normal.
Squinting patellae occur when the feet point forward but the knees squint towards each other representing abnormal femoral and tibial torsion. Isolated external tibial torsion may be noted if the patella points forward but the feet point outwards more than 10 –150.
If the patients’ complains of instability then it may be useful to ask the patient to demonstrate the direction they feel the knee moves into. This may elicit lateral or postero-lateral instability.