Evaluating the Outcomes of Trochleoplasty in the Treatment of Patellofemoral Instability in the Adolescent and Young Adult Knee With Severe Trochlear Dysplasia: A Minimum 2-Year Follow-up.

Background: Recurrent patellofemoral joint instability in adolescent and young adult patients is associated with several anatomic risk factors. A lack of consensus exists as to which risk factor(s) should be addressed at the time of surgery, but the presence of a severely dysplastic femoral trochlea has been described as an indication for surgical intervention. Furthermore, literature has suggested that a severely dysplastic trochlea can be a contributing factor to a failed medial patellofemoral ligament reconstruction (MPFLR) alone.

Purpose: To investigate the postoperative outcomes of patients <20 years of age who underwent primary trochleoplasty in combination with MPFLR and lateral retinacular lengthening (LRL), with some receiving concomitant tibial tubercle osteotomy (TTO).

Study design: Cohort study; Level of evidence, 3.

Methods: A retrospective review of prospectively collected data performed in patients <20 years old who underwent trochleoplasty with MPFLR with ≥2 years of follow-up. Demographics, concomitant procedures, patient-reported outcome (PRO) measures, magnetic resonance imaging, and radiographs were reviewed. Patients who also underwent TTO were compared with those who did not.

Results: A total of 21 knees from 15 patients (11 female, 4 male) with mean age of 16.4 years (13.7-19.8 years) were included. All patients had severe trochlear dysplasia and were treated with trochleoplasty, MPFLR, and LRL. Ten knees underwent additional TTO and were compared with those who did not (n = 11). The Pediatric International Knee Documentation Committee, Kujala, and Lysholm scores collected at a mean of 3.3 years (range, 2-6 years) postoperatively did not differ significantly between groups. There were no patient-reported postoperative episodes of patellar instability by the final follow-up.

Conclusion: At a minimum 2-year follow-up, there were no statistically significant differences observed in PROs between patients who underwent trochleoplasty and concomitant TTO and those who had trochleoplasty alone, with neither group having any reported episodes of postoperative patellar instability. Furthermore, at final follow-up favorable PROs were achieved in patients who underwent trochleoplasty for the treatment of their patellofemoral instability with severe trochlear dysplasia.