Background

Medial patellofemoral ligament (MPFL) reconstruction has demonstrated a very high success rate with improved patella stability, physical function, and patient-reported outcomes. Systematic reviews have demonstrated a very low redislocation rate, ranging from 2.1-5.1%. Previous studies have also reported a complication rate of up to 26.1% following MPFL surgery.

Purpose

The purpose of this study was to assess the complication rate as well as the number of subsequent surgical procedures in patients with recurrent lateral patellofemoral instability following a patellar stabilization surgery including an MPFL reconstruction.

Methods

Patients with recurrent patellofemoral instability who underwent a patellofemoral stabilization including an MPFL reconstruction (n = 363) were assessed at a minimum of 2-years post-operative. Of the 363 patients, 98 (27%) underwent a contralateral surgery during the study period, providing data for 461 knees. Pathoanatomic risk factors were assessed pre-operatively. Complications and redislocations as well as additional operative procedures were recorded. Disease-specific quality of life was assessed with the Banff Patellofemoral Instability Instrument (BPII). Descriptive statistics including rates, means, and standard deviations were calculated.

Results

Complications following surgery were recorded in 34/461 knees (7.4%). Redislocation of the patella occurred in 23/461 knees (5.0%). There were three deep infections and one superficial infection, five knees developed arthrofibrosis, there was one tibial tubercle fracture, and one non-union of a femoral osteotomy. There were no patella fractures, incorrect femoral tunnel placement, medial dislocations, implant failures, deep vein thromboses or pulmonary emboli. A subsequent surgical procedure was performed in 94/461 knees (20.4%), with 120 procedures completed in total. Subsequent surgeries included hardware removal in 54 knees (45% of additional procedures), knee arthroscopy in 39 knees (32.5%) and revision patellar stabilization procedures in 23 knees (19.2%). The most common reason for knee arthroscopy was pain secondary to chondral cartilage injury. The mean pre-operative BPII score was 25.5 (SD 13.4), and post-operatively was 65.7 (SD 14.6).

Conclusion

This study demonstrated a low overall complication rate of 7.4% following patellar stabilization using an à la carte approach to surgical treatment. The most common complication was re-dislocation in 5.0% of knees. Additional surgery was performed in 20.4% of knees, of which almost half was expected for removal of hardware. These results indicate a low complication and redislocation rate following patellar stabilization procedures that included an MPFL reconstruction.