# Validation on Method of Measuring the Knee Joint Force Sense and Application in Patients With Knee Osteoarthritis

## TL;DR

This study validates a new method to measure knee joint force sense and finds that it is not affected by BMI or knee osteoarthritis.

## Contribution

A novel and reliable method for measuring knee joint force sense is developed and validated.

## Key findings

- The reflex contraction latency of the biceps femoris showed high reliability with an ICC of 0.950.
- Striking force significantly affects force sense, but BMI does not.
- Knee osteoarthritis does not significantly influence knee joint force sense.

## Abstract

Background: Force sense reflects the efferent activity capacity of proprioception. Currently, methods for measuring force sense in the knee joint is lack. This study aims to validate a constructed test system and to explore the characteristics of force sense in patients with knee osteoarthritis (KOA).

Methods: Seventy-five subjects were recruited: 30 for verifying the reliability of test system and exploring the impact of body mass index (BMI) and the striking force on force sense; 20 healthy adults and 25 KOA patients for the method application. The force sense test system comprised a self-designed force application apparatus and a wireless surface electromyography (sEMG) device (DELSYS Inc, USA). The reflex contraction latency of muscles was considered as the force sense. The intraclass correlation coefficient (ICC) was used to verify the reliability.

Results: The reflex contraction latencies of biceps femoris (BF) was the shortest and ICC in the two tests is 0.950 (p < 0.001). No significant differences in force sense were found between different BMI groups (p=0.065), and there was no notable interaction between BMI and striking force (p=0.283). A significant difference in force sense was observed between different striking forces (p < 0.001). There were no significant differences in force sense of bilateral sides between healthy people and KOA patients (p=0.126, p=0.315).

Conclusion: The force sense testing method established in this study is applicable for measuring knee joint force sense. BMI did not affect knee joint force sense but striking force did, and subjects with different BMI chose the same striking force; KOA did not influence the force sense of knee joint.