Association Between Articular Incongruence After Trochleoplasty and Long-term Patellofemoral Osteoarthritis.

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.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The authors conducted a retrospective review of patients who underwent sulcus-deepening trochleoplasty between 2003 and 2013 and identified 43 patients after their initial search. 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 radiographs 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 patient satisfaction scores were also collected. Pearson correlation analysis was used to evaluate the relationship between articular surface angles and OA, and Spearman rank correlation analysis was used to assess the association between categorical and ordinal variables. A 2-tailed Student test was used to compare the mean values of the clinical scores between groups.

RESULTS

Ten patients (10 knees) met the inclusion criteria, with a mean follow-up of 15.3 ± 3.93 years. The PA and TA were 148.5°± 24.75° and 148.5°± 17.85°, respectively, with a mean patellofemoral incongruence of 21.4°± 16.03°. None of the patients had preoperative OA, and 4 (40%) developed postoperative OA: 2 with Iwano grade 1 and 2 with Iwano grade 2. Higher patellofemoral incongruence was found to correlate with the development of patellofemoral OA ( = .017). No independent correlation was found between the TA and OA ( = .553) or the PA and OA ( = .884). The satisfaction, Kujala, and IKDC scores were 8.2 ± 1.75, 82.5 ± 10.09, and 84.4 ± 9.79, respectively. Only 1 patient (10%) reported a traumatic patellar dislocation, none required reoperations, and all (100%) indicated they would undergo surgery again.

CONCLUSION

This study demonstrated that patellofemoral incongruence after trochleoplasty was associated with the development of long-term OA without an independent correlation with a flat trochlea or a flat patella.