Classification of trochlear dysplasia as predictor of clinical outcome after trochleoplasty

Abstract

Purpose Sulcus-deepening trochleoplasty restores the trochlear groove in patients with patellofemoral instability and underlying trochlear dysplasia. There are types of dysplasia both with (B and D) and without (A and C) a supratrochlear spur. The aim of this study was to identify influencing factors for the clinical outcome following trochleoplasty. Methods Forty-four knees in 38 patients who underwent trochleoplasty for instability (type A in 9, B in 15, C in 9 and D in 11 knees) were assessed clinically with the Kujala score and radiologically with radiographs and MRI. The median follow-up was 4 (2-7.8) years. Results At follow-up, the median Kujala score had improved from 68 (29-84) to 90 (42-100) points (P \ 0.001). Instability (P \ 0.001) and pain (P = 0.027) decreased significantly, but in 3 knees, pain was worse postoperatively. Twenty-seven knees were ranked as excellent, 10 as good, 2 as fair and 5 as poor. Overall, dysplasia types B and D benefited more from surgery than types A and C. The postoperative MRI revealed no chondrolysis or subchondral necrosis, but deterioration of cartilage on the lateral trochlear facet was identified. Conclusion Trochleoplasty is a useful and reliable surgical technique to improve patellofemoral instability in patients with a dysplastic trochlea. While improved stability is predictable, pain is less predictable and may even increase following surgery. The overall results were directly dependent on the type of the dysplasia, with a significantly better clinical outcome in type B and D. The clinical relevance of this study is that severe dysplasia can successfully be treated with trochleoplasty. Level of evidence III.

Surgical treatment of patellofemoral instability using trochleoplasty or MPFL reconstruction: a systematic review

“…While all articles defined clear inclusion criteria, only half of them described exclusion criteria [10,15,23,27,29,33,35]. There were different inclusion criteria in most of the studies.…”

“…Fucentese et al [10] have shown superior results in type B and D trochlear dysplasia than in type A and C when treated with trochleoplasty. Some consensus exists on the fact that trochleoplasty cannot be the only solution for all types of patellofemoral instability.…”

Patellar instability

“…Fucentese et al reviewed 44 knees in 38 patients with patellar instability treated with deepening trochleoplasty and no other procedures performed at that time. A 37% of patients reported no improvement in pain and 8% reported worse pain following surgery than before 60 . There were six cases of recurrent instability and 18% of patients said they would not repeat the surgery 60 .…”

“…A 37% of patients reported no improvement in pain and 8% reported worse pain following surgery than before 60 . There were six cases of recurrent instability and 18% of patients said they would not repeat the surgery 60 . Fucentese et al concluded that pain relief following trochleoplasty is not predictable but that this procedure does improve stability in most patients.…”

Patella, Femoropatellar Joint, and Infrapatellar Fat Pad

“…The role of postoperative MR imaging is to assess the resulting femoral groove depth and the lateral femoral inclination. However, 10-30 % of patients may suffer increased pain after intervention, and MR images may show progression of degenerative changes in the femoropatellar joint [ 62 ].…”