Biomechanical assessment of varus-valgus range of motion of normal elbow joint using prototype measuring device.

Introduction: Elbow joint stability is provided by the medial and lateral collateral ligaments, joint surface alignment, and the joint capsule. The contribution of the joint capsule is relatively minor and varies with the position of the joint. The normal range of forearm abduction and adduction in the elbow joint is estimated to be between 5 and 10°. The aim of the paper was to determine precisely the physiological range of elbow joint motion in the frontal plane (laxity), which, apart from the knowledge gained, will provide a means to assess the effect of the surgical treatment of elbow joint contractures by comparing the stability of operated and healthy joints.

Material And Methods: The measurements were carried out using UB-01, a prototype device produced by ANT Polska, in a group of 52 healthy volunteers.

Results: The mean valgus and varus deviation of the elbow joint was 11.2° (6.4° 16.1°) and 6.6° (3° 10.7°), respectively. The mean degree of elbow joint laxity was 17.8° (10.6° 26.5°). The difference in laxity between two opposite elbow joints in the same person was, on average, 1.2° (0.1° 3.8°). In healthy persons, the amplitude of deviation for both elbows is significantly smaller than 2°.

Conclusions: 1. There are major differences in elbow joint laxity between individuals. 2. Nevertheless, laxity values of two elbow joints in the same individual are very similar. This observation allows for the healthy elbow to be treated as a reference while assessing the affected joint's stability in a patient following conventional surgery for elbow joint contracture.