Computational comparison of medializing tibial tubercle osteotomy and trochleoplasty in patients with trochlear dysplasia

Abstract

Medial patellofemoral ligament reconstruction (MPFLR) has emerged as the procedure of choice for recurrent patellar dislocation. This addresses soft tissue injury but does not address underlying anatomic factors, including trochlear dysplasia, that are commonly present and increase risk of dislocation. Quantification of the stability offered by other surgical interventions, namely, medializing tibial tubercle osteotomy (mTTO) and trochleoplasty, with and without MPFLR, may provide insight for surgical choices in patients with trochlear dysplasia. We developed subject‐specific finite element models based on magnetic resonance scans from a cohort of 20 patients with trochlear dysplasia and recurrent patellar dislocation. The objectives of this study were (1) to compare patella stability after mTTO and trochleoplasty procedures; (2) to evaluate whether it is necessary to perform an MPFLR in combination with the mTTO or trocheoplasty procedure; and (3) to quantify the robustness of patellar stability to variability in knee kinematics. Trochleoplasty performed better than mTTO at stabilizing the patella between 5° and 30° flexion. For both mTTO and trochleoplasty procedures, it was beneficial to also perform MPFLR—inclusion of MPFLR halved the magnitude of patellar laxity predicted in the simulations. Simulations that did not include any medial patellofemoral ligament restraint were also more sensitive to variation in tibiofemoral internal–external kinematics.

Lateral trochlear inclination measured by the transepicondylar axis holds potential for evaluating trochlear dysplasia in patients with lateral patellar dislocation

“…The indication for trochleoplasty was reported to be severe TD (Dejour type B–D) with an LTIp value of < 12° [29]. Some researchers merely used the subjective grading methods of TD, the Dejour classification, to make surgical strategies, but an objective parameter that could help surgeons with trochleoplasty procedure decision‐making is lacking [3, 8, 27]. There is a risk of excessive medical treatment when there is an inaccurate subjective assessment of TD, and objectively evaluating TD is of great significance.…”