Trochleaplasty for Patellar Instability Due to Trochlear Dysplasia: A Minimum 2-year Clinical and Radiological Follow-up of 19 Knees

Background: Recurrent patellar dislocation may be associated with trochlear dysplasia. Trochleaplasty is a surgical procedure which strives to deepen the trochlear groove. We evaluated the clinical and radiological effect of trochleaplasty after a minimum follow-up of 2 years.

Patients And Methods: We examined 19 knees in 16 patients at a mean of 3 years after trochleaplasty. Postoperatively, a subjective questionnaire, a Kujala score, and tests for potential patellar redislocation and apprehension were evaluated. On radiographs we evaluated the preoperative and postoperative crossing sign, trochlear depth, trochlear bump, and patellar height. On CT scans, the pre- and postoperative tibial tuberosity to trochlear groove distance (TTTG) and the patellar inclination angle were measured.

Results: 16 of 19 knees improved subjectively. The Kujala score increased from 56 to 80 points at the latest follow-up. None of the patients sustained a redislocation. 5 patients had medial parapatellar tenderness, including 4 with persistent apprehension. Radiological signs of trochlear dysplasia were corrected.

Interpretation: Patellofemoral instability with underlying trochlear dysplasia can be treated successfully by trochleaplasty.