Congenital dislocation of the knee.

Congenital dislocation of the knee is a very rare condition, the incidence in Scandinavia hitherto not being known with certainty. Thirteen patients treated during the years 1960 to 1983 with 19 affected knees were reviewed and followed up. Findings of muscular imbalances in nine of these cases and of spinal abnormalities in four cases strongly indicate neuromuscular imbalance as an aetiological factor. The minimum incidence was estimated to be 0.017 per mille or approximately 1 per cent of the incidence of congenital dislocation of the hip. Recommendations for treatment are that manipulation should be carried out gently, and if not successful within 2-3 months and in all cases of Grade III, an operation is indicated. Too many newborn children in this series had manipulation fractures or slipped epiphyses. However, signs of fracture had disappeared at follow-up in most cases.