One hundred and twenty knee injuries diagnosed as traumatic haemarthrosis were reviewed. All were initially treated by aspiration and splintage. None had major ligamentous or major bony injury clinically or radiographically when first seen. The incidence of anterior cruciate damage was 17 per cent and that of crack fracture was 29 per cent. Many of those aged under thirty had anterior cruciate damage. Those over thirty commonly had crack fractures. Sixty-five per cent of the patients had no symptom when reviewed. A total of 9.9 per cent needed further operations. The younger patients, especially those with an injury from sport, should be referred to a specialist knee clinic for further management.