Summary
Deepening trochleoplasty using a thick osteochondral flap technique with a dedicated cutting guide is not associated with increased risk of secondary OA and functional outcome deterioration at more than 2 years.
Abstract
Background
Recurrent patellar dislocations and trochlear dysplasia are strongly associated with cartilage lesions and onset of early patellofemoral osteoarthritis (PF OA). Trochleoplasty is widely used to address trochlear dysplasia and was reported as a successful method to control patellar instability. However, the procedure is technically demanding and might accelerate progression of OA by failure to restore joint congruency and chondrolysis. We hypothesized that trochleoplasty with preservation of subchondral bone integrity by keeping thick osteochondral flaps and using a dedicated cutting guide will result in the absence of secondary PF OA and preservation of functional outcome.
Purpose
The primary aim of the study is to assess patello femoral cartilage more than 2 years after sulcus-deepening trochleoplasty by MRI. Secondary objective is to analyze the evolution of patient-reported outcome scores between 1-year postop and time to follow up.
Study design: prospective cohort study; level of evidence, 2.
Methods
between 2015 and 2020, deepening trochleoplasty with a thick flap was performed in 36 consecutive patients with high grade trochlea dysplasia (75% Dejour type B, 25% Dejour type D). Sex ratio 0.8, age 23.9±7.3 years, BMI 23.2±.4.6 Kg/m2. Trochleoplasty was undertaken using a saw blade guided by K-wires positioned with a dedicated guide. It was combined with medial patello femoral ligament reconstruction in all cases, tibial tuberosity osteotomy in 69 % (25/36), and lateral patellar retinaculum Z-lengthening in 91% (33/36). The most common postoperative adverse event was arthrofibrosis (14%; 5/36). Follow-up of 3.9 years (min 2 years; max 7 years). A radiologist independently measured cartilage thickness on MRI at baseline to time point in four focal regions of the patello femoral joint. Marked points included the medial and lateral facet of the patella as well as the medial and lateral part of the trochlea. Each baseline-time point segmentation pair was compared and no statistically significant difference was observed. No significant difference was observed for KOOS subscales , Kuijala anterior knee pain scale and Lysholm scores when comparing 1 year postop to time to follow up values.
Conclusion
Deepening trochleoplasty using a thick osteochondral flap technique with a dedicated cutting guide is not associated with increased risk of secondary OA and functional outcome deterioration at more than 2 years.