Radiographic Measurements of Normal Knee Joint Space in Adults

Introduction: The knee joint is the space between the femoral and tibial condyles. The tibiofemoral articulations are separated by articular cartilages and menisci; with little contributions from cruciate ligaments. These are collectively seen on a radiograph as a radiolucent area between the bony tibial and femoral condyles. This study was conducted to measure the normal knee joint space in patients referred for X-Ray to the Department of Radiology of a tertiary care hospital. Methods: This descriptive cross-sectional study was performed from 1st January to 1st April 2021 in the Department of Radiology and Imaging, Tribhuvan University Teaching Hospital (TUTH). A total of 157 patients were involved. The radiographic joint space width in the knee joint was measured in both medial and lateral compartments of bilateral knees in correlation with age and gender. Results: The mean right medial, left medial, right lateral, and left lateral spaces for females were 0.25±0.08 cm, 0.23±0.09 cm, 0.49±0.10 cm, and 0.49±0.29 cm respectively. Similarly, the mean right medial left medial, right lateral, and left lateral spaces for males were 0.26±0.07 cm, 0.10±0.09 cm, 0.18±0.09 cm, and 0.17±0.08 cm respectively. There was a strong positive correlation between both right and left joint spaces about age. Conclusion: The radiographic reference values for the joint space width were obtained, showing a positive correlation with age and no significant gender variations in bilateral knees.