Clinical outcome after reconstruction of the medial patellofemoral ligament in patients with recurrent patella instability.

PURPOSE

We present the clinical results of a large consecutive, prospective, single-clinic series of patients treated with medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability.

METHODS

The study included 224 patients undergoing MPFL reconstruction in a total of 240 knees between 2008 and 2011. Indication for surgery was two or more patellar dislocations and ADL limitations due to patella instability.

SURGICAL PROCEDURE

A gracilis tendon autograft was fixed in drill holes in the medial edge of the patella and with screws at the femoral MPFL insertion point. Outcomes were evaluated with the Kujala Anterior Knee Pain Score and pain scores preoperatively and at follow-up (12-60 months). Furthermore, incidences of re-dislocations, subluxations and revision surgery were evaluated.

RESULTS

The Kujala score improved from 62.5 (17) to 80.4 (18) (p<0.001) at the 1-year follow-up. Pain during activity improved from 3.2 (2.6) to 1.3 (2.7) at 1 year (p<0.001). The revision rate was 2.8%. Some degree of pain at the medial femoral condyle was seen in 30% of the patients. The reconstruction was supplemented with a tibial tuberosity osteotomy in 23% of cases. The outcome for these patients did not differ from that of patients with isolated MPFL reconstruction. Female gender BMI>30, age>30 years and grade 3-4 cartilage injury predisposed a poor subjective outcome.

CONCLUSIONS

The present study is the largest MPFL reconstruction patient material reported to date. MPFL reconstruction with a gracilis tendon autograft consistently normalised the patella stability and improved knee function. Moderate medial pain was seen. Age above 30, obesity, cartilage injury and female gender are predictors of a poor subjective outcome.

LEVEL OF EVIDENCE

Level IV.