2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


The Correlation between Anatomical Measurements of the Knee Performed on Magnetic Resonance Imaging Scans and Proximal Patellar Tendinopathy

André Richard Da Silva Oliveira Filho, Student, Joao Pessoa, Paraiba BRAZIL
Igor Almeida Gomes, Student, Joao Pessoa, Paraiba BRAZIL
Carlos Fernando de Mello Junior, MD, PhD, Prof., Joao Pessoa, Paraiba BRAZIL
Severino Aires de Araújo Neto, MD, PhD, Prof., Joao Pessoa, Paraiba BRAZIL
RAFAEL LARA DE FREITAS, MD, PhD, JOAO PESSOA, PARAIBA BRAZIL

Federal University of Paraiba, Joao Pessoa, Paraiba, BRAZIL

FDA Status Not Applicable

Summary

Patellar tendinopathy is an injury common in athletes, characterized by tendon degeneration. Extrinsic factors like jumping activity are primary contributors, while intrinsic factors like anatomy of bone accidents are less understood. This study used MRI to compare knee joint measurements, such as TTTG and trochlear angle, between a PT group and a control group, to evaluate correlations.

Abstract

Introduction

Patellar tendinopathy (PT), or Jumper's Knee, is an overuse injury of the patellar tendon, common in athletes who practice repetitive and explosive activities. It is characterized by micro-ruptures, mucoid degeneration, fibrinoid necrosis and areas of regeneration with fibroblasts and new blood vessels. PT often occurs in the proximal part of the tendon, near the apex of the patella, characterized as proximal patellar tendinopathy (PPT). Extrinsic factors, such as the type of physical activity, are the main players in the development of PPT. Magnetic resonance imaging (MRI) helps to assess degenerative changes and knee morphology, which are essential for the diagnosis and management of PPT. Nevertheless, the role of intrinsic factors in PPT such as limb misalignment and the anatomy of bone accidents remain less studied, therefore our aim was to evaluate the association between anatomical measurement and PPT in the present study.

Methods

This is a cross-sectional retrospective study with the aim of comparing measurements of the knee joint on MRI scans between two groups: a case group with PPT knees and a control group. The case and controls were chosen accordingly with the MRI signals of PPT, encompassing a series of changes: thickening in the proximal part of the tendon, adjacent edema, hyperintensity with blurring or disorganization of the fibers, presence of edema in axial and sagittal sections in T2 with fat suppression analyzed prospectively by an experienced radiologist. The measurement realized were: patellar inclination, Insall-Salvati index, the angle of the patellar apex in the sagittal plane, the lateral inclination of the patella in the axial plane, the horizontal distance between the anterior tuberosity of the tibia and the trochlear groove of the femur - TTTG, the subchondral angle of the patella (Wiberg’s angle), the angle of the patellar cartilage, the subchondral angle of the trochlear groove of the femur and the cartilage angle of the trochlea of the femur. The measurement team was blinded to group allocation. Student's t-test was used to compare the means of the measurements between the PPT and the control group.

Results

78 knee MRI scans were collected, with age 40.1 ± 16.1 (mean ± standard deviation), 35 were allocated on the PPT group and 43 on the control group. The PPT group showed significantly lower angulation of the femoral trochlea, both of the bone (128.35º ± 9.63º for PPT and 134.79º ± 7.66º for controls; p = 0.001) and of the local cartilage (137.59º ± 7.51º for PPT and 142.19º ± 7.04º for controls; p = 0.007). On the other hand, no statistically significant differences were found between the means of the PPT and control groups for the other measurements taken.

Conclusions

This study found that a lower angulation of the femoral trochlea (both bone and cartilage) is correlated with the presence of PPT. These findings support the development of further longitudinal prospective research to explore causal relationships in this association and their clinical implications.