Return To Sport Following Stabilization Surgery For Recurrent Patellar Instability In Patients Undergoing Isolated Mpfll Reconstruction Vs. Combined Mpfl Reconstruction And Tibial Tubercle Osteotomy
Authors: Swensen Stephanie Joelle , Nguyen Joseph , Marmor William A. , Gruber Simone , Stein Beth E. Shubin 
Published: March 2020

Objectives:

Acute patellar instability is a common and disabling injury among young athletes and the risk of recurrence is as high as 80% in certain populations. The essential lesion of lateral patellar dislocations is MPFL rupture. However, bony risk factors for dislocation have also been identified, including patella alta, trochlear dysplasia, and a lateralized tibial tubercle. Significant debate exists regarding the optimal treatment due to the multifactorial nature of the pathology. Isolated MPFL reconstructions have demonstrated good functional outcomes within the literature. Failure to address bony malalignment has been proposed as a source of failure for these procedures. The addition of realignment techniques, such as tibial tubercle distalizations and medializations has been recommended to improve patellar stability in select patients. There is a paucity of literature on redislocation rates, return to sport, and functional outcomes after patellofemoral stabilization surgery. The purpose of the current study is to compare redislocation rates, return to sport, and functional outcomes between patients undergoing isolated MPFL reconstruction versus patients who have undergone MPFL and TTO as treatment for recurrent patellofemoral instability. It is hypothesized that patients who have undergone isolated MPFL reconstructions will have improved outcomes and return to sport rates compared to combined MPFL reconstruction and TTO.

Methods:

A retrospective chart review of prospectively collected data from 2014-2017 was conducted to identify consecutive athletes who underwent primary isolated MPFL reconstruction or MPFL reconstruction combined with TTO. Exclusion criteria included concomitant cruciate ligament surgery, multi-ligament surgery, and failed previous surgery. Patient information, including redislocation rate, radiographic data, sporting level, return to sport, previous dislocation rates, and subsequent surgeries were recorded. Generalized estimating equation modeling was used to analyze longitudinal outcome scores (Kujala, IKDC), activity level (HSS, Ped-FABS), and health-related quality of life (KOOS-PS, KOOS-QOL) collected at baseline, 1-year, and 2-year postoperatively.

Results:

A total of 100 patients were included in the study (71 MPFL; 29 MPFL+TTO). Redislocation rates were low for both MPFL and MPFL+TTO groups (1/70 and 1/28, respectively). No differences were found in reported incidence of post-op dislocation or subluxation (P=0.498 and 191, respectively). Both groups reported a high rate of RTS with MPFL at 87% and TTO at 89% (P>0.999). However, the ability to return to the same or higher level of RTS was significantly higher in MPFL patients (85%) versus TTO (57%) (P=0.009). And for those patients who were able to RTS, the time to RTS was significantly lower in MPFL patients (8.9 months) compared to TTO patients (13.5 months) (P<0.001). Both study groups had significant improvement over time in all functional outcome scores. Patients in the MPFL+TTO group consistently reported with worse functional scores at baseline.

Conclusion:

Patients undergoing MPFL reconstruction with or without correction of bony malalignment reported significant improvement over time with high return to sport rates and low recurrent dislocation rates. However, patients undergoing MPFL+TTO reported lower scores compared to MPFL patients at baseline and 2-years follow-up.