Stepwise lengthening of quadriceps extensor mechanism for severe obligatory and fixed patella dislocators: Four-year clinical and surgical outcomes.

Objectives: The purpose of this study was to report clinical and surgical outcomes of medial patellofemoral ligament reconstruction (MPFLR) and concomitant quadriceps lengthening to treat fixed and obligatory patellofemoral instability (PFI) in the pediatric population.

Methods: Patients with obligatory or fixed PFI who underwent simultaneous MPFLR and quadriceps lengthening from 2008 to 2020 were reviewed. Of the 413 records, 24 fit the inclusion criteria. Demographic information, surgical details, associated diagnoses, and outcome measures were collected for each knee. Complications and additional surgeries were also obtained.

Results: The final cohort included 20 patients (10 male, 10 female), with a total of 24 knees. The average age at the time of surgery was 11.9 ​± ​3.1 (5.4-17.3). Seventeen were obligatory dislocators in flexion and 7 were fixed dislocators. Average follow-up was 4.3 ​± ​2.4 (1.3-9.4) years. One patient was lost to follow-up and excluded from the study. The mean outcome measures were as followed; KOOS 82, HSS Pedi-FABS 9, IKDC 76, Kujala 78, BPII 67, and SANE 90. Six patients had subsequent instability episodes. Ten patients had a subsequent surgery.

Conclusions: Reports on quadriceps lengthening to treat PFI in the pediatric population are rare. Six (25 ​%) of the 24 knees included had subsequent PFI. Although this is a high rate of recurrent instability, no second surgeries were indicated for infection, extensor mechanism weakness, or contracture. The authors conclude that simultaneous MPFLR and stepwise quadriceps lengthening can be used to effectively manage fixed and obligatory PFI in this difficult patient population.

Level Of Evidence: IV.