Abstract
Objectives:
Patellar instability, prevalent among adolescent athletes, is commonly managed with medial patellofemoral ligament (MPFL) reconstruction surgery with or without a Fulkerson tibial tubercle osteotomy. Limited research exists on how patellar instability affects gait in pediatric patients. This study examines gait kinematics and patient-reported outcomes in pediatric patients with patellar instability that was significant enough for surgical intervention. The objective is to analyze pre- and post-operative changes in gait analysis to better understand the dynamic pathology of patellar instability. We hypothesized that gait kinematics in patients with significant patellar instability would differ significantly from normative data and improve with reconstruction surgery.
Methods:
A retrospective chart review was conducted on 33 patients, aged 10-19, who underwent MPFL reconstruction surgery, with or without Fulkerson tibial tubercle osteotomy, between 1/1/2014-5/1/2024 at a single center regional pediatric orthopedic specialty hospital. Gait analysis was performed pre- and post-operatively, with an average of 479.94 days between surgery and post-operative analysis. Data included patient demographics, physical exam, radiographic measures, kinematics, and patient-reported outcomes (PROs).
Results:
Kinematic analysis revealed significant differences between patients with patellar dislocation and normative controls specifically loading response of the knee and mean hip rotation while in stance. However, no notable difference was found between pre- and post-operative measurements within the cohort. Patients who were indicated for a Fulkerson osteotomy based on TT-TG measurements did not exhibit significant pre- or post-operative kinematic differences compared to those treated with MPFL alone. The J-sign showed significant improvement postoperatively, with many patients no longer exhibiting it on physical examination. PROs showed significant post-operative improvements across all domains of the Pediatric Outcomes Data Collection Instrument (PODCI), Patient-Reported Outcomes Measurement Information System (PROMIS), and Goal Attainment Scaling (GAS).
Conclusions:
Kinematic analysis was found to be non-informative for surgical decision-making. Although kinematics differed significantly from normative values pre-operatively, these differences did not improve post-operatively. Despite this, MPFL reconstruction with or without Fulkerson osteotomy significantly improved patient-reported outcomes, with high patient satisfaction post-operatively. The relationship between abnormal kinematics and patellar instability remains uncertain. Our findings, which show favorable outcomes despite abnormal kinematics, prompt several questions: Does abnormal kinematics contribute to patellar instability in adolescents, or is the inverse true? Are the two factors unrelated? Further investigation is needed to clarify this relationship.
Patients with patellar instability were determined to have abnormal sagittal plane kinematics. MPFL with or without Fulkerson osteotomy reconstruction surgery improves patient-reported outcomes in pediatric patients with patellar instability, despite a lack of post-operative kinematic improvement.
