Pettersson, Kurt

Purpose: A biomechanical functional assessment was performed on a newly designed wrist hemiarthroplasty implant with aimed to identifying differences between the native wrist and wrist following the hemiarthroplasty procedure with [Formula: see text] and without a proximal row carpectomy (Hemi). Methods: Six cadaveric wrists were mounted on a custom testing fixture and underwent a series of functional tests to investigate differences in range of motion, muscles moment arms, and axis of rotation between the intact and post-operative wrists. The tested movements included manually-driven flexion-extension, radial-ulnar deviation, dart throwers motion, and circumduction. Results: The only significant change in range of motion was a decrease in flexion between the intact [Formula: see text] and both the Hemi [Formula: see text] and [Formula: see text] [Formula: see text] conditions. Minor differences in the mean position and variability of the axis of rotation’s piercing point were identified. A statistically significant decrease in the flexion moment arm of the flexor carpi radialis was identified between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions. Statistically significant decreases were also identified in the radial deviation moment arms of the extensor carpi radialis brevis’ between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions and the flexor carpi radialis’ between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions as well as in the ulnar deviation moment arm of the extensor carpi ulnaris between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions. Conclusions: While some statistically significant functional changes were identified between the native and hemiarthroplasty wrist, the findings suggest that post-operative function is equally acceptable in hemiarthroplasty with and without resection of the proximal carpal row.

Objectives: To prospectively evaluate patient related outcome measures after total wrist arthroplasty (TWA) using four different total wrist implants operated at a single referral center in Sweden. Methods: 206 primary TWAs were assessed preoperatively and after one year postoperatively with respect to the following eight outcome measures: Range of motion (flexion/extension, radial/ulnar deviation, pronation/supination), hand grip strength, Canadian Occupational Performance Measure (COPM), performance and satisfaction, Visual Analog Scale (VAS) pain scores at rest and in activity. Results: The Maestro TWA had a significantly greater improvement of radial/ulnar deviation than the Biax and Remotion TWAs. COPM performance and satisfaction improved more for the Maestro and Universal 2 prostheses than the Biax and Remotion. Conclusions: All four TWAs offer reduced VAS-scores and improved COPM-scores with preserved hand grip strength and somewhat improved range of motion. The Maestro TWA performed favorably compared to the Remotion TWA. Implant design may affect patient related outcome.