The Effect of Distal Radius Fractures on 3-Dimensional Joint Congruency

PURPOSE: Whereas the goal of distal radius fracture treatment is anatomical restoration, controversy exists as to whether it is the severity of the disruption of joint alignment at the time of fracture or residual malalignment after healing that determines outcome. The objective of this study was to compare joint contact mechanics bilaterally a minimum of 3 years following a distal radius fracture. Our hypothesis was that 3-dimensional joint space would be reduced in individuals following wrist fracture and that these changes in joint load lead to the development of degenerative arthritis. To test the hypothesis, an interbone spacing algorithm was used to determine whether 3-dimensional joint space and contact mechanics were altered in the distal radioulnar (DRUJ) and radiocarpal joints following a wrist fracture. METHODS: In 16 subjects with previous unilateral wrist fractures, 3-dimensional interbone distance (joint space), a measure of joint congruency and 3-dimensional alignment, was quantified from reconstructed computed tomography bone models of the distal radius, ulna, scaphoid, and lunate. RESULTS: At an average of 8 years following fracture, joint interbone spacing area was reduced in the radiolunate joint of the injured wrist in comparison with the uninjured wrist. The joint interbone spacing area was decreased in the DRUJ and radioscaphoid joint of the injured wrist compared with the uninjured wrist but this difference was not statistically significant. CONCLUSIONS: This study demonstrates the use of a noninvasive tool that can be used to examine joint loading and suggests that further investigation into the association between altered joint loading and the development of posttraumatic arthritis is needed, especially in the radiocarpal joints. CLINICAL RELEVANCE: This paper provides a noninvasive image-based framework that can be used to examine joint contact area over time and provides preliminary data examining the effect of a distal radius fracture on the joint congruency of the DRUJ and radiocarpal joints.