Association of trochlear dysplasia with degenerative abnormalities in the knee: data from the Osteoarthritis Initiative

Abstract

Objective To evaluate trochlear morphology as a potential risk factor for patellofemoral osteoarthritis, determined by morphological and quantitative measurements of cartilage degeneration using 3T magnetic resonance imaging (MRI) of the knee. Materials and Methods MR images of right knees of 304 randomly selected subjects, aged 45–60 years, from the Osteoarthritis Initiative (OAI) progression cohort were screened for trochlear dysplasia, defined by an abnormal trochlear depth. Out of 304 subjects, n=85 demonstrated a shallow trochlea (depth ≤3mm; 28%). In these, and also in a random sample of controls with normal trochlear depth (n=50), the facetal ratio and the sulcus angle were calculated and knee structural abnormalities were assessed by using a modified Whole-Organ-MR-Imaging Score (WORMS). Cartilage segmentation was performed and T2 relaxation times and patellar cartilage volume were determined. ANOVA and multivariate regression models were used for statistical analysis of the association of MRI structural measures and trochlear morphology. Results Knees with a shallow trochlea showed higher patellofemoral degeneration (WORMS mean ±standard deviation, 11.2±0.5 versus 5.7±0.6; Multivariate regression, P<0.001) and lower patellar cartilage volume than controls (900±664mm3 versus 1671±671mm3; P<0.001). Knees with an abnormal medial-to-lateral facetal ratio (<0.4) showed increased patellofemoral WORMS scores (12.3±0.9 versus 8.3±0.5; P<0.001). Knees with an abnormal sulcus angle (>170°) also showed increased WORMS scores (12.2±1.1 versus 8.6±0.6; P=0.003). T2 values at the patella were significantly lower in the dysplasia group with a shallow trochlea. However, significance was lost after adjustment for cartilage volume (P=0.673). Conclusion Trochlear dysplasia, defined by a shallow trochlea, was associated with higher WORMS scores and lower cartilage volume, indicating more advanced osteoarthritis at the patellofemoral joint.

Are There Sex Differences in Knee Cartilage Composition and Walking Mechanics in Healthy and Osteoarthritis Populations?

“…Our data support these observations because lower extremity alignment affected the differences in tibiofemoral cartilage T 1q but not the differences in patellofemoral cartilage T 1q . One anatomic factor that has been shown to be related to patellofemoral OA that we did not evaluate in our study is trochlear dysplasia [28]. Furthermore, it may be possible that the interaction of sex and alignment may be different for medial and lateral patellofemoral compartments, although recent studies have not reported it [23].…”

Patellofemoral pain: consensus statement from the 3rd International Patellofemoral Pain Research Retreat held in Vancouver, September 2013

“…There is new evidence that abnormal structure or alignment of the PFJ may lead to cartilage damage and focal areas of loading and stress manifested as bone marrow lesions (BMLs). Stefanik et al 13 reported that knees in the MOST cohort with patella alta and abnormal trochlea morphology were associated with cartilage damage and BML, with similar findings reported from the Osteoarthritis Initiative cohort 18…”

Characteristics of femorotibial joint geometry in the trochlear dysplastic femur

“…In addition to patellar instability, trochlear morphology has been identified as a potential risk factor for patellofemoral osteoarthritis (Jungmann et al. ) that can be treated by patellofemoral arthroplasty in a middle‐aged patient and by total knee arthroplasty (TKA) in the elderly (Ackroyd et al. ).…”