Ligament strains and sprains ± traumatic synovitis
Serious disorders not to be missed
primary in bone
Acute cruciate ligament tear
Juvenile chronic arthritis
Referred pain: back or hip disease
Intra-articular loose bodies
Ruptured popliteal (Baker’s) cyst
Spinal dysfunction (referred)
Is the patient trying to tell me something?
Psychogenic factors relevant, especially with possible injury compensation.
The history helps diagnosis, especially evaluating the nature of the injury. Define whether the pain is acute or chronic, dull or sharp, continuous or recurring. Keep in mind age-related causes and past history.
The provisional diagnosis may be evident from a combination of the history and simple inspection of the joint but the process of testing palpation, movements (active and passive) and specific structures of the knee joint helps pinpoint the disorder.
connective tissue antibodies
plain X-ray including special views
arthrography: CT scan, MRI (excellent for investigating internal ‘derangement’)
aspiration of fluid for culture or crystal examination.
Examine the hip and lumbosacral spine if examination of the knee is normal but knee pain is the complaint.
Acute haemarthrosis following an injury should be regarded as an anterior cruciate ligament tear until proved otherwise.