Clinical outcomes of medial patellofemoral ligament repair in recurrent (chronic) lateral patella dislocations.

PURPOSE: The specific aim of this project was to review a homogenous group of patients who had chosen to undergo medial patellofemoral ligament (MPFL) repair to stabilize their patella after repeat (chronic) patellofemoral dislocations and to record the success of this procedure in stabilizing the patella against further lateral dislocations.

METHODS

This is a retrospective study of 55 knees in 48 patients who underwent a repair of the medial patellofemoral ligament by a single surgeon over a 4-year period. The endpoint of the study was a documented patellofemoral dislocation or a minimum 2-year follow-up.

RESULTS

Fifty-five knees in 48 patients underwent a MPFL repair/reattachment. Patella alta, as defined by the Insall-Salvati (I/S) ratio, was within normal limits in 6 (14%). The I/S ratio was greater than 1.2 in 38 patients (86%) and greater than 1.4 in 23 patients (52%). Trochlear dysplasia as defined by a positive crossing sign on a true lateral radiograph and/or a sulcus angle on axial view of greater than 145 was present in 45/47 (96%). Successful management of the knee as defined by no further patella dislocation occurred in 22 knees. Nineteen knees sustained a redislocation event (46%).

CONCLUSIONS

The surgical procedure of operative repair (reattachment) of the MPFL to its femoral attachment had a significantly high rate of failure in this patient group of chronic (repeat) lateral patellar dislocators.