Reconstruction of the knee extensor mechanism after chronic buttonhole deformity

Chronic buttonhole deformity of the knee after patellectomy is an unusual and rare complication. Reconstruction of the extensor mechanism is difficult as the tissues are thinned and friable. The technique of repair was reinforced using semitendinosus and gracilis. The post-operative care initially concentrated on range of motion and then power. This allowed MRC grade four power with a range of movement of 0 degrees-125 degrees at 1 year.