Acute dislocation of the patella: Clinical, radiographic and operative findings in 64 consecutive cases

The clinical, radiographic and operative findings in 64 consecutive acute dislocations of the patella were analyzed. Both patellofemoral joints were symptomless before dislocation in 58 patients. The sulcus angle of the femur on the affected side was larger than on the contralateral side in one half, and a fresh marginal patellar fracture was demonstrated in one third of the cases. The stability of the patella could not be reliably estimated in tangential views taken with the knee in 20 degrees flexion; especially false negative findings were numerous.