Patellar-tendon transfer by the slot-block method for recurrent subluxation and dislocation of the patella.

In sixty-five knees followed for an average of 4.5 years after treatment of subluxation or dislocation of the patella by the slot-block method of medial patellar-tendon transfer, the results were satisfactory in fifty-four (83%) and unsatisfactory in eleven (17%). Recurrent subluxation or dislocation occurred in three (5%) of the knees and was attributed to insufficient displacement. Chondromalacia of the patella became worse after transfer in three of the sixty-two knees in which the distal realignment was technically correct. Two knees (3%) required patellectomy because of patellofemoral symptoms and there were nineteen complications in seventeen knees, including loss of motion in six, wound infection in six, displacement of the bone block in three, recurrent dislocation in three, and rupture of the patellar ligament in one. The method is believed to give superior results but it is technically demanding.