The Effect of Radial and Ulnar Length Change on Distal Forearm Loading

The effect of distal radial and ulnar length change on forearm bone loading is not well understood during simulated dynamic wrist loading. This thesis presents two studies which investigate the effect of these length changes on distal forearm loading under simulated dynamic wrist motion. The first study investigates the effect of radial length change on axial loading at the distal radius and ulna and relationship between ulnar variance and distal forearm loading. The complex variation in axial loads in the distal radius and during length change and dynamic wrist motion were studied and discussed. There was no correlation between native variance and distal loads. The second study investigates the effect of ulnar change on axial loading at the distal radius and ulna and the effect of triangular fibrocartilage ligament complex (TFCC) on this relationship. Variation in axial loads during ulnar lengthening followed similar trends to radial shortening and vice versa

Arthroscopic debridement for primary elbow osteoarthritis with and without capsulectomy: a comparative cohort study

© 2017 The British Elbow & Shoulder Society. Background: Arthroscopic elbow debridement for primary osteoarthritis may be performed with or without a joint capsulectomy. The purpose of this comparative cohort study was to compare range of motion (ROM) and early complications between patients with and without anterior capsulectomy. Methods: In total, 110 patients with primary osteoarthritis of the elbow who underwent an arthroscopic debridement for primary osteoarthritis were reviewed with a minimum of 3 months postoperative follow-up. The first group consisted of 51 patients who had a concomitant capsulectomy and the second group consisted of 59 patients who either had a capsulotomy or did not have the capsule addressed. Results: There was significantly greater pre-operative stiffness in the group who had an anterior capsulectomy versus those who did not. A greater improvement in arc of ROM occurred in patients who had a concomitant capsulectomy compared to patients without (24° versus 12°) (p \u3c 0.003); however, there were no significant differences in final ROM between groups. There were no statistically significant differences in the incidence of complications between the groups (16% capsulectomy versus 18% no capsulectomy). Conclusions: Elbow arthroscopy and debridement for primary elbow osteoarthritis yields satisfactory motion at short-term follow-up with or without a capsulectomy. The incidence of early complications was low at this tertiary referral centre, with no significant differences between groups

An In Vitro Study to Determine the Effect of Ulnar Shortening on Distal Forearm Loading During Wrist and Forearm Motion: Implications in the Treatment of Ulnocarpal Impaction

© 2019 American Society for Surgery of the Hand Purpose: To evaluate the effect of ulnar shortening on distal forearm loading following simulated dynamic motion. Methods: Ulnar shortening was simulated using a custom-built adjustable implant to simulate up to 4 mm of ulnar shortening (–4 mm) in 9 cadaveric extremities. Load cells were placed in the distal ulna and radius to quantify axial loading. Using a wrist and forearm motion simulator, absolute and percentage loads were measured during dynamic flexion, ulnar deviation (UD), flexion dart throw (DT), and pronation. Results: There was a significant decrease in absolute and percentage distal ulnar loads at each interval of ulnar shortening during flexion, UD, DT, and pronation. The distal ulna bore no compressive loads, and in fact, tensile loads were measured in the ulna at 2 mm of ulnar shortening during DT and pronation, at 3 mm during flexion, and at 4 mm during UD. Conclusions: A progressive decrease in distal ulnar loads with generation of tensile loads was observed with sequential ulnar shortening. Clinical relevance: Ulnar shortening greater than 2 mm can result in tensile loading in the distal ulna. When managing ulnar impaction syndrome, excessive shortening may not be required to provide relief of symptoms

Effect of Radial Lengthening on Distal Forearm Loading Following Simulated In Vitro Radial Shortening During Simulated Dynamic Wrist Motion

© 2019 American Society for Surgery of the Hand Purpose: To evaluate the effect of radial length change on distal forearm loading during simulated dynamic wrist motion. Methods: A custom-built adjustable radial implant was used to simulate up to 4 mm of distal radius shortening (–4 mm) and 3 mm of lengthening (+3 mm). Load cells were placed in the distal radius and ulna in cadavers to measure their respective axial loads. The specimens were mounted on a wrist motion simulator that produced active wrist motion via tendon actuation. To simulate radial lengthening osteotomy following radial shortening from malunion, the radius was sequentially lengthened by 1-mm intervals from –4 mm to +3 mm. Radial and ulnar loads were measured during simulated wrist flexion, ulnar deviation (UD), and flexion dart throw (DT) at each interval of radial lengthening up to +3 mm. Results: During wrist flexion and UD, for each millimeter of radial lengthening from –4 mm to the native length, there was a significant increase in distal radial loads. No significant change in radial load was observed beyond the native length during flexion and UD. There was no change in distal radial loads during DT for each interval of radial lengthening from –4 mm to +3 mm. A sequential decrease in ulnar loads was observed as the radius was lengthened from –4 mm to +3 mm for all wrist motions evaluated. Conclusions: Radial lengthening beyond the native length was not detrimental to radial loading and further reduced distal ulnar loading; achieving at least native ulnar variance seems to be appropriate to restore normal biomechanical loading based on this in vitro study. Clinical relevance: Lengthening of the radius beyond native variance in the setting of ulnar impaction syndrome, distal radius malunion, or distal radioulnar instability may not result in excessive loading of the distal radius and further reduces loading on the distal ulna. Surgeons should obtain contralateral wrist x-rays to serve as a template when performing distal radius osteotomies