Medial Patellofemoral Ligament Reconstruction with and without Tibial Tubercle Osteotomy

Abstract

Objectives: 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. The role of tibial tubercle osteotomy (TTO) as an adjunct to MPFL reconstruction remains controversial. Our purpose was to evaluate a cohort of patella instability patients undergoing surgical soft tissue stabilization with or without concomitant TTO. Our hypothesis was that there would be no difference between cohorts in baseline values, subjective outcome scores at final follow-up, or 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, with or without concomitant TTO. Indications for TTO were at the surgeon’s discretion, including elevated TT-TG, Caton-Deschamps ratio, and/or unloading chondral lesion(s). Surgery was performed by a single sports fellowship trained surgeon. Pre-surgical and post-surgical patient reported outcomes were collected including KOOS domains, PROMIS (global health, mental health, physical function, pain interference), IKDC, SANE, and Marx scores. Complications requiring re-operation (infection, stiffness, recurrent instability) were recorded. Results were analyzed statistically. Results: The cohort was comprised of 87 patients (95 knees), with 25 males (28.7%) and 62 females (71.3%). The MPFL-TTO cohort had 32 patients (38 knees) and the MPFL-Iso had 55 patients (57 knees). The average age of the MPFL-TTO cohort was 28.3 (range 19.5-44.6) and the average age of the MPFL-Iso group was 29.8 (18.7-55.3). There was no significant difference in pre-operation outcome scores between groups (p>.05). Significant improvements were seen for all KOOS domains in both patient cohorts with no significant differences detected between groups. SANE, IKDC, and PROMIS scores improved significantly with no differences detected between groups. Marx activity score at 6 months post-operatively was significantly different between the groups favoring the isolate MPFL reconstruction cohort. (MPFL-TTO 0.79 +/- 2.15 vs. 4.61 +/- 5.44 in the MPFL-Iso group (p=0.01)). In terms of complications, 4 knees in the MPFL-TTO group required further surgery (2 for stiffness, 1 for infection, and 1 for fracture) and 6 knees in the MPFL-Iso cohort required surgery (4 for stiffness, 1 for infection, and 1 for recurrent instability). Neither the overall complication rate of 4 vs. 6 (p=1) nor the recurrent instability rate of 0 vs. 1 (p=0.41) was significant. Conclusion: In a cohort of patients undergoing MPFL reconstruction, the addition of an appropriately indicated TTO appears to be both safe and effective. Both MPFL-TTO and MPFL-Iso groups demonstrated significant improvement in the majority of subjective outcome scores without major difference between groups. Marx activity scores were higher for the isolated MPFL reconstruction cohort at relatively short term follow-up. The surgical complication profile was similar between groups. Further work is needed to clearly define the role of TTO as an adjunct procedure to MPFL reconstruction.