Total wrist arthroplasty

The contribution of the histopathological examination to the diagnosis of adverse local tissue reactions in arthroplasty

The histopathological examination of the periprosthetic soft tissue and bone has contributed to the identification and description of the morphological features of adverse local tissue reactions (ALTR)/adverse reactions to metallic debris (ARMD). The need of a uniform vocabulary for all disciplines involved in the diagnosis and management of ALTR/ARMD and of clarification of the parameters used in the semi-quantitative scoring systems for their classification has been considered a pre-requisite for a meaningful interdisciplinary evaluation.

This review of key terms used for ALTR/ARMD has resulted in the following outcomes: (a) pseudotumor is a descriptive term for ALTR/ARMD, classifiable in two main types according to its cellular composition defining its clinical course; (b) the substitution of the term metallosis with presence of metallic wear debris, since it cannot be used as a category of implant failure or histological diagnosis; (c) the term aseptic lymphocytic-dominated vasculitis- associated lesion (ALVAL) should be replaced due to the absence of a vasculitis with ALLTR/ALRMD for lymphocytic-predominant and AMLTR/AMRMD for macrophage-predominant reaction.

This review of the histopathological classifications of ALTR/ARMD has resulted in the following outcomes: (a) distinction between cell death and tissue necrosis; (b) the association of corrosion metallic debris with adverse local lymphocytic reaction and tissue necrosis; (c) the importance of cell and particle debris for the viscosity and density of the lubricating synovial fluid; (d) a consensus classification of lymphocytic infiltrate in soft tissue and bone marrow; (e) evaluation of the macrophage infiltrate in soft tissues and bone marrow; (f) classification of macrophage induced osteolysis/aseptic loosening as a delayed type of ALTR/ARMD; (g) macrophage motility and migration as possible driving factor for osteolysis; (h) usefulness of the histopathological examination for the natural history of the adverse reactions, radiological correlation, post-marketing surveillance, and implant registries.

The review of key terms used for the description and histopathological classification of ALTR/ARMD has resulted in a comprehensive, new standard for all disciplines involved in their diagnosis, clinical management, and long-term clinical follow-up.

Cite this article: EFORT Open Rev 2021;6:399-419. DOI: 10.1302/2058-5241.6.210013

[Revision surgery after total wrist arthroplasty]

BACKGROUND

Wrist arthroplasty is still an exceptional indication in the field of hand surgery. In recent years, it has become increasingly accepted as an alternative to wrist arthrodesis as the ultima ratio for panarthrosis or similar destruction of the wrist. In particular, the patient's desire for functional integrity also plays an important role.

COMPLICATIONS

While there were often complications with earlier prosthesis designs of the older generations and only a short survival rate could be achieved, this has improved, if the indication of the so-called fourth generation prostheses is done properly. Survival rates of over 10 years are no longer uncommon, even without revision operations. Currently, the indication for hemiarthroplasty has been increasing, particularly in the case of post-traumatic destruction. Those who are seriously interested in endoprosthesis should also be able to treat the associated complications. The present article is intended to provide an overview of common or potential complications in the context of wrist arthroplasty and to demonstrate possible solutions by presenting case studies. The basics of primary implantation are, therefore, not discussed. Reference is made to further literature.

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

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.

What Are the Risk Factors and Complications Associated With Intraoperative and Postoperative Fractures in Total Wrist Arthroplasty?

BACKGROUND

Total wrist arthroplasty (TWA) can relieve pain and preserve some wrist motion in patients with advanced wrist arthritis. However, few studies have evaluated the risks and outcomes associated with periprosthetic fractures around TWAs.

QUESTIONS/PURPOSES

(1) What is the risk of intraoperative and postoperative fractures after TWAs? (2) What factors are associated with increased risk of intraoperative and postoperative fracture after TWAs? (3) What is the fracture-free and revision-free survivorship of TWAs among patients who sustained an intraoperative fracture during the index TWA?

METHODS

At one institution during a 40-year period, 445 patients underwent primary TWAs. Of those, 15 patients died before 2 years and 5 were lost to followup, leaving 425 patients who underwent primary TWAs with a minimum of 2-year followup. The primary diagnosis for the TWA included osteoarthritis ([OA] 5%), inflammatory arthritis (90%), and posttraumatic arthritis (5%). Indications for TWA included pancarpal arthritis combined with marked pain and loss of wrist function. The mean age of the patients was 57 years, BMI was 26 kg/m², and 73% were females. Six different implants were used during the 40-year period. Mean followup was 10 years (range, 2-18 years).

RESULTS

Intraoperative fractures occurred in nine (2%) primary TWAs, while postoperative fractures occurred after eight (2%) TWAs. After analyzing demographics, comorbidities, and surgical factors, intraoperative fractures were found to be associated with only age at surgery (hazard ratio [HR], 1.10; 95% CI, 1.03-1.20; p = 0.006) and use of a bone graft (HR, 5.80; 95% CI, 1.18-23.08; p = 0.03). No factors were found to be associated with increased risk of postoperative fractures; specifically, intraoperative fracture was not associated with subsequent fracture development. The 5-, 10-, and 15-year Kaplan-Meier survival rates free of postoperative fracture were 99%, 98%, and 95%, respectively. The 5- and 10-year revision-free survival rates after intraoperative fracture were 88% and 88%, respectively, compared with 84% and 74% without an intraoperative fracture (p = 0.36). Furthermore, the survival-free of revision surgery rates for aseptic distal loosening at 5 and 10 years were 88% and 88%, respectively, compared with 93% and 87% without a fracture (p = 0.85).

CONCLUSIONS

Intraoperative fractures occur in approximately 2% of TWAs. These fractures do not appear to affect long-term implant survival or risk of fracture. Patient age and the need for bone graft were the only factors in the risk of intraoperative fractures. Postoperative fractures also occur in 2% of TWAs, but often result in revision surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Registration-Based Morphometry for Shape Analysis of the Bones of the Human Wrist

We present a method that quantifies point-wise changes in surface morphology of the bones of the human wrist. The proposed method, referred to as Registration-based Bone Morphometry (RBM), consists of two steps: an atlas selection step and an atlas warping step. The atlas for individual wrist bones was selected based on the shortest ℓ2 distance to the ensemble of wrist bones from a database of a healthy population of subjects. The selected atlas was then warped to the corresponding bones of individuals in the population using a non-linear registration method based on regularized ℓ2 distance minimization. The displacement field thus calculated showed local differences in bone shape that then were used for the analysis of group differences. Our results indicate that RBM has potential to provide a standardized approach to shape analysis of bones of the human wrist. We demonstrate the performance of RBM for examining group differences in wrist bone shapes based on sex and between those of the right and left wrists in healthy individuals. We also present data to show the application of RBM for tracking bone erosion status in rheumatoid arthritis.