Association of patellofemoral morphology and alignment with the radiographic severity of patellofemoral osteoarthritis

Yike Dai,Chongyang Xu,Hongrui Zhang,Ai Guo,Heyong Yin,Naicheng Diao

doi:10.1186/s13018-021-02681-2

Abstract

BackgroundRisk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.MethodsA retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic grade of PFOA and tibiofemoral osteoarthritis (TFOA), lateral and medial trochlear inclination angle, sulcus angle, and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG) and patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters, and the relationships between each of these measures and the severity of PFOA were investigated.ResultsBy studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P < 0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle; and type I patella was 8.80 (p = 0.043), 16.51 (P < 0.001), 0.04 (P < 0.001), and 0.18 (p = 0.048) respectively.ConclusionsExtreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.

Highlights

Risk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood
patellofemoral joint (PFJ) malalignment typically manifests as lateral patellar tilt, lateral displacement, or a combination of the two, which is a deviation of the patella relative to trochlea that may lead to abnormal stress transmitted through the PFJ [7]
The sulcus angle and lateral patellar angle were negatively correlated with the radiographic severity radiographic grade 3 of lateral PFOA were 8.8 for the lowest quarter of the sulcus angle (P = 0.043) and 16.51 for the lowest quarter of the lateral patellar angle (P < 0.001), respectively

Summary

Introduction

Risk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA. Patellofemoral joint osteoarthritis (PFOA) is a type of knee OA, which is one of the most commonly affected compartments. Different from radiographic TFOA, the risk factors of the radiographic severity of PFOA have not been as thoroughly studied. A previous study identified the association between PFOA and both abnormal trochlear sulcus morphology and tibiofemoral alignment [8]. There is little evidence that patella height, lateral patellar displacement, and patellar tilt are associated with PFOA. We speculate that the increasing of patella height, sulcus angle (i.e., a flatter trochlear), lateral patellar displacement, and lateral patellar tilt will lead to patella instability and cause PFOA. There are few studies about the relationship between patella morphology with the severity of PFOA

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