Incidence of 2nd Surgery after Medial Patellofemoral Ligament Reconstruction and Simultaneous Osteochondral Fracture Fixation in Pediatric Patients Treated for Patellar Dislocation

OBJECTIVES: Osteochondral fractures occur in 5-15% of cases of acute or recurrent patellar dislocations. In these settings, early surgical intervention with biodegradable fixation nails is recommended to optimize healing. The aim of this study was to determine the incidence of recurrent instability and second surgery following osteochondral fracture fixation with concomitant medial patellofemoral ligament (MPFL) reconstruction. METHODS: We conducted a retrospective cohort study of 321 MPFL reconstructions performed by a single surgeon between 2011 and 2019. Thirty-eight knees underwent MPFL reconstruction with osteochondral fixation. Demographic data, surgical details, date of latest radiographic and clinical follow-up, and subsequent surgical procedures were collected. RESULTS: Thirty-seven MPFL reconstructions with osteochondral fracture fixation in 36 patients were performed by a single surgeon from 2011 to 2019 (1 bilateral). The average age at surgery was 14.8 years (range 10.6– 19.6 years). The average length of clinical follow-up was 2.1 years (range 0.3– 5.5 years). The average number of biodegradable fixation nails used was 4.4 (range: 2-8). Twenty-seven (72.9%) fractures were fixed to the patella and 10 were fixed to the lateral femoral condyle or trochlea. There was 1 report of recurrent instability. Ten (27%) patients required a second surgery on the ipsilateral knee, and underwent chondroplasty (n=8), removal of biodegradable fixation nails (n=4), removal of hemi-epiphysiodesis or TTO hardware (n=2), revision MPFL with tibial tubercle osteotomy (n=1), lateral meniscus repair (n=1). The one patient who required revision MPFL reconstruction has juvenile idiopathic arthritis and underwent 3 additional surgeries after the initial MPFL procedure. Eight patients (22%) underwent a second surgery to address cartilage damage or removal of nails. The mean time to second surgery was 40.0 weeks (range:11-82.7). Of the four patients who required removal of nails, the average number of nails initially placed was 7 ± 1.7. This was significantly more than the patients who did not require second surgery related to nail removal (4.1 ± 1.6, p < .05). CONCLUSION: Approximately 78% of patients undergoing MPFL reconstruction and osteochondral fracture fixation with biodegradable nails showed good fracture healing and patellar stability while 22% went on to require a second surgery. The second surgery most commonly involved debridement of an unhealed portion of the cartilage.