# Mechanical Angle and Its Relationship to Intercondylar Fossa Stenosis: An Anatomical Donor Study

## TL;DR

This study explores how mechanical angles and knee anatomy relate to ACL injury risk, finding sex-specific biomechanical differences but no clear predictors for a specific knee condition.

## Contribution

The study provides new insights into sex-specific biomechanical factors related to ACL injury risk.

## Key findings

- Mechanical angle, Q-angle, and ICF shape did not collectively predict ICF stenosis.
- Sex-specific differences in mechanical angle were found, suggesting unique biomechanical factors.
- A negative correlation between Q-angle and mechanical angle was observed.

## Abstract

Background

Current literature reveals several anatomic variations that can predispose patients to non-contact anterior cruciate ligament (ACL) injuries. The intercondylar fossa (ICF) plays a crucial role in both acute and chronic knee injuries, housing critical structures like the ACL and posterior cruciate ligament (PCL). This anatomical donor study investigates the relationship between mechanical angle, ICF stenosis, and the Q-angle to understand the potential predisposition to ACL injury.

Methods

A retrospective anatomical donor study was conducted in the anatomical laboratory at Lincoln Memorial University-DeBusk College of Osteopathic Medicine (LMU-DCOM). The study utilized 27 formalin-fixed whole-body cadaveric donors (16 male, 11 female), from which 39 knees were dissected and analyzed. Standardized dissection techniques were employed to expose relevant osseous and soft tissue structures. Measurements of mechanical axis angle, quadriceps (Q) angle, ICF morphology, and femoral and tibial bone dimensions were obtained using consistent anatomical landmarks. All measurements were recorded in a controlled laboratory environment to minimize variability and ensure data reliability.

Results

Logistic regression analysis showed that mechanical angle, Q-angle, and ICF shape were not collectively predictive of ICF stenosis (p > 0.05). However, a significant sex difference in mechanical angle (p = 0.0041) suggests unique biomechanical factors. A negative correlation between Q-angle and mechanical angle (-0.2452) highlighted a complex interplay. Chi-squared analysis indicated trends in ICF shape variation between sexes. Interobserver analysis demonstrated consistent measurements.

Conclusions

Mechanical angle, Q-angle, and ICF shape collectively failed to predict ICF stenosis. However, sex-specific differences in mechanical angle may contribute to ACL injury risk. These findings may indicate the importance of biomechanical variations in injury prevention strategies. Future research should consider age-diverse and longitudinal studies to better understand these dynamics.