Of a consecutive series of 144 Attenborough knee replacements, 107 were re-examined between two and six years after operation and revealed a high incidence of complications. Wound problems were common and led to deep infection in four knees. When a patellar implant was used fracture of the patella followed in 17.5% of knees, but when the patella was not resurfaced 16% of knees developed patellofemoral pain of sufficient severity to require a further operation. In 10% of knees, definite loosening of one or both of the major components occurred.