Proximal‐distal shift of the center of rotation in a total wrist arthroplasty is more than twice of the healthy wrist

Abstract

Reproduction of healthy wrist biomechanics should minimize the abnormal joint forces that could potentially result in the failure of a total wrist arthroplasty (TWA). To date, the in vivo kinematics of TWA have not been measured and it is unknown if TWA preserves healthy wrist kinematics. Therefore, the purpose of this in vivo study was to determine the center of rotation (COR) for a current TWA design and to compare its location to the healthy wrist. The wrist COR for six patients with TWA and 10 healthy subjects were calculated using biplane videoradiography as the subjects performed various range‐of‐motion and functional tasks that included coupled wrist motions. An open‐source registration software, Autoscoper, was used for model‐based tracking and kinematics analysis. It was demonstrated that the COR was located near the centers of curvatures of the carpal component for the anatomical motions of flexion‐extension and radial‐ulnar deviation. When compared to healthy wrists, the COR of TWAs was located more distal in both pure radial deviation (P < .0001) and pure ulnar deviation (P = .07), while there was no difference in its location in pure flexion or extension (P = .99). Across all coupled motions, the TWA's COR shifted more than two times that of the healthy wrists in the proximal‐distal direction (17.1 vs 7.2 mm). We postulate that the mismatch in the COR location and behavior may be associated with increased loading of the TWA components, leading to an increase in the risk of component and/or interface failure.

The effect of planar constraint on the definition of the wrist axes of rotation

“…Understanding the natural axes of a joint is crucial for novel prosthetic and arthroplasty design (Brumbaugh et al, 1982;Stokdijk et al, 2000) and musculoskeletal modelling (Goislard De Monsabert et al, 2018), as the success of these techniques depends on replicating normal joint kinematics. Axes of rotation have been used to validate arthroplasty design (Hooke et al, 2015), and assess joint function (Pothrat et al, 2015), quantify joint instability (Duck et al, 2003), to determine appropriate joint modelling simplifications (Sheehan, 2010), classify joint pathology (Wolf and Degani, 2006), and determine joint centres of rotation with the aim of improving rehabilitation activities and reduce arthroplasty failure (Akhbari et al, 2020;Amabile et al, 2016). Thus, it is vital that the description of the axes and their relationship to each other in vivo is understood.…”

"Off label" use of the ReMotionTM total wrist for treatment of advanced stage of post-traumatic pancarpal wrist osteoarthritis: Report of two cases and review of literature

“…Furthermore, we observed a functional outcome which was marked better than function in the affected opposite wrist. A newest TWA study revealed that the center of motion for extension-flexion in TWA is localized in the proximal third of capitate similar to a healthy wrist, whereas the center of motion for radial-ulnar deviation in TWA is localized in contrast to a healthy wrist at the distal tip of capitate [56]. The question is: Does placement of both screws for fixation a carpal TWA component with convergence to distal into the capitate directly aligned to the two centers of motion in the absence of rigid fixation the carpal plate along the entire width of carpus and without crossing a carpometacarpal joint improve function and decrease the risk of loosening?…”

Anatomy, Biomechanics, and Loads of the Wrist Joint

“…There exists still a controversy about the existence of a "center of rotation" of the wrist. If one exists it will be found in the head of the capitate, for both FE and RUD [3,[36][37][38][39].…”