Thick-shell sulcus-deepening trochleoplasty for recurrent patellar dislocation leads to clinically meaningful improvements and high patient satisfaction in adolescents with open physes

Objectives: To evaluate clinical and radiological outcomes of thick-shell, sulcus-deepening trochleoplasty in patients with open distal femoral physes and less than two years of growth remaining. We hypothesized that patients would have clinical and radiographic improvements in addition to high patient-reported outcomes following thick-shell, sulcus-deepening trochleoplasty.

Methods: Bone age was determined on preoperative magnetic resonance imaging (MRI) using the Pennock Knee Bone Age Atlas. Pre- and postoperative radiographs were used to measure the anatomic lateral distal femoral angle (aLDFA) and Blumensaat angle. International Knee Documentation Committee (IKDC), Kujala, and numerical patient satisfaction scores were assessed. Pre- and postoperative aLDFA and Blumensaat angles as well as patient-reported outcomes were analyzed via the Wilcoxon signed-rank test.

Results: Seventeen adolescents (21 knees) with DeJour Types B and D trochlear dysplasia and open distal femoral physes underwent Dejour thick-shell, sulcus-deepening trochleoplasty at a single institution. In twelve females (16 knees, 76.2%) the median chronological and bone ages at the time of operation were 14.9 and 14.3 years, respectively. In 5 males (5 knees, 27.7%), the median chronological and bone ages at the time of operation were 15.7 and 15.2 years, respectively. Mean follow-up time was 64 months postoperatively. Physes were closed in all knees at the time of final clinical and radiographic follow-up. The mean change in aLDFA and Blumensaat Angle was 0.73 (p ​= ​0.1074, 95% CI -0.09-1.57) and 0.88° (p ​= ​0.0477, 95% CI 0.10-1.88), respectively. Median IKDC scores improved from 57.3 preoperatively to 90.9 postoperatively, for a mean difference of 26.1 (p ​= ​0.00064, 95% CI 18.0-34.2). Median Kujala scores improved from 55.0 preoperatively to 95.0 postoperatively, for a mean change of 30.2 (p ​= ​0.0008, 95% CI 19.6-40.8). Overall mean numerical patient satisfaction was high (mean 9.26/10). One of 21 knees (4.8%) underwent additional surgery to address recurrent patellar instability.

Conclusion: Thick-shell sulcus-deepening trochleoplasty for addressing recurrent lateral patellar instability in patients with open distal femoral physes and less than two years of growth remaining is safe and provides clinically meaningful improvements in addition to high patient satisfaction when combined with other patellar stabilization procedures.

Level of evidence: IV, Retrospective Case Series.