Summary
Outcomes of consecutive cohorts undergoing MPFL repair or MPFL reconstruction for chronic patella instability demonstrated improvements in both groups with a significantly higher complication profile in the MPFL repair group.
Abstract
Purpose
The medial patellofemoral ligament (MPFL) is the primary soft-tissue restraint against lateral patellar displacement. Surgery to address MPFL incompetence is the current gold standard for recurrent patellofemoral instability. Controversy remains regarding the role of MPFL repair versus reconstruction in the setting of chronic patella instability. Our purpose was to investigate the outcomes and complication profile of consecutive cohorts undergoing MPFL repair and MPFL reconstruction. Our hypothesis was that the MPFL reconstruction group would have higher subjective outcome scores and lower complication profile.
Methods
Following IRB approval, retrospective review of prospectively collected data identified a consecutive cohort of patients undergoing soft tissue stabilization for recurrent patella instability. Surgery was performed by a single sports fellowship trained surgeon between 2011-2018. MPFL repair was performed on patients prior to November of 2015 and MPFL reconstruction from December 2015 to present. Patients undergoing concomitant bony realignment procedures were included. Pre-surgical and post-surgical patient reported outcomes were collected including PROMIS, KOOS, IKDC, Marx, Tegner, and SANE scores. Complications requiring re-operation (infection, stiffness, recurrent instability) were recorded. Results were analyzed statistically.
Results
130 patients (144 knees) were included. MPFL repairs were performed on 49 knees (34.03%) and MPFL reconstructions were performed on 95 knees (65.97%). There were 38 males (29.2%) and 92 females (70.8%). Mean age was 17.2 years-old for the repair cohort (range, 10.6-38.6) and 23.9 for the reconstruction cohort (range, 13.1-50.8, p=0.000). There were no differences in baseline pre-operative scores between groups, with the exception of lower KOOS Symptoms score in the MPFL reconstruction group (52.24 +/- 16.94 vs. 68.75 +/- 13.77, p=0.011). At final follow-up (range 6-59.3 months), MPFL repair and reconstruction groups demonstrated significant improvements in all KOOS domains. MPFL reconstruction group also demonstrated significant improvements from baseline in PROMIS domains, IKDC, Tegner, and SANE scores. At minimum 6 month follow-up, the MPFL repair group had greater PROMIS mental health (55.76 +/- 9.77 vs. 49.81 +/- 8.51, p=0.038) and KOOS quality of life scores (50.00 +/- 11.42 vs. 30.82 +/- 28.05, p=0.033). The complication rate in the MPFL repair group was significantly higher in comparison to the reconstruction group (22.45% vs. 10.59%, p=0.033). Repair group had a significantly higher rate of revision to reconstruction (8 vs. 1, 16.3% vs 1.1%, p=0.0003). Reconstruction group had higher rate of surgery for stiffness (4 vs. 1, 4.2% vs 2.0%, p=0.500).
Conclusions
In the setting of chronic patella instability, both MPFL reconstruction and MPFL repair demonstrated significant improvements in all KOOS domains. MPFL reconstruction also demonstrated significant improvement in IKDC, PROMIS, Tegner, and SANE scores. KOOS QOL and PROMIS mental health were better in the MPFL repair group. There was a significantly higher complication profile in the MPFL repair group, including increased revision rate to reconstruction.
Keywords: MPFL, medial patellofemoral ligament, patellar dislocation, patellar instability, reconstruction, repair