Summary

Post-trochleoplasty patellofemoral incongruence is associated with the development of long-term OA

Abstract

Background

Trochleoplasty has shown promising results in selected patients with patellar instability. However, concerns persist regarding its potential relationship with long-term osteoarthritis (OA) and the underlying causes.

Purpose

To evaluate the correlation between postoperative patellofemoral incongruence after trochleoplasty and long-term OA.

Methods

The authors conducted a retrospective review of patients who underwent sulcus-deepening trochleoplasty between 2003 and 2013. All patients were assessed at a minimum follow-up of 10 years. Preoperative, immediate postoperative, and end-of-follow-up lateral and axial view knee x-rays were used to evaluate patellofemoral OA using the Iwano classification, the patellar articular surface angle (PA), and the trochlear articular surface angle (TA). Data on patellar redislocation, reoperations, and International Knee Documentation Committee (IKDC), Kujala, and satisfaction scores were also collected.

Results

Ten patients met the inclusion criteria with a mean follow-up of 15.3 ± 3.93 years. The PA and the TA were 148.5 ± 24.75 and 148.5 ± 17.85, respectively, with an average patellofemoral incongruence of 21.4 ± 16.03. None of the patients had preoperative osteoarthritis, and four (40%) developed postoperative OA: two with Iwano type I and two with Iwano type II. Higher patellofemoral incongruence was found to correlate with the development of patellofemoral OA (p = 0.017). No independent correlation was found between the TA and OA (p = 0.553) or the PA and OA (p = 0.884). The satisfaction, Kujala, and IKDC scores were 8.2 ± 1.75, 82.5 ± 10.09, and 84.4 ± 9.79, respectively. Only one patient (10%) reported a traumatic patellar dislocation, none required reoperations and all (100%) indicated they would undergo surgery again.

Conclusion

Post-trochleoplasty patellofemoral incongruence is associated with the development of long-term OA without an independent correlation with a flat trochlea or a flat patella.