What characteristics make a patient most amenable to successful total wrist arthroplasty?
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‘Bright future ahead’ for total wrist arthroplasty
Historically, patients with rheumatoid arthritis were considered ideal candidates for total wrist arthroplasty because of profound bone destruction, debilitating pain and a relatively low activity level.
In fact, a study by Christina Ward, MD, and colleagues showed that nearly 50% of a particular total wrist design had failed by 10 years, calling into question the advisability of wrist replacement for inflammatory arthritis. Concurrent publications from Europe showed improved prosthetic survival rates in post-traumatic and osteoarthritic patients. Indeed, osteoporotic bone and inflammatory destruction of the wrist’s supporting ligaments likely contributed to high rates of prosthetic loosening in patients with RA.
Today, an ideal candidate for total wrist arthroplasty (TWA) is a symptomatic 50- to 70-year-old individual with post-traumatic pan-carpal arthritis or scapholunate advanced collapse who has failed nonoperative or operative treatment and is willing to modify their activity level to increase implant longevity. Other indications include Kienböck’s disease, well-controlled RA and failed surgical repair. A meta-analysis by Per Fischer, MD, and colleagues demonstrated Kaplan-Meier 10-year survival rates of 92%, with improved rates in newer wrist designs. This year we received FDA approval and introduced the KinematX novel midcarpal TWA design (Extremity Medical LLC) that mimics the anatomy and kinematics of the human wrist and was designed from the world’s largest open-source wrist kinematic database. As has been demonstrated from large joint arthroplasty results, data-driven kinematic design decreases stress on the bone-implant interface and improves prosthetic survival. Newer designs and proper patient selection portend a bright future ahead for TWA.
- Fischer P, et al. J Hand Surg Am. 2020;doi:10.1016/j.jhsa.2020.02.006.
- Wolfe SW. KinematX midcarpal total wrist arthroplasty: A preliminary report. Presented at: Lyon Wrist Virtual Meeting. Oct. 18, 2021; (virtual meeting).
Scott W. Wolfe, MD, FAAOS, is chief emeritus of hand and upper extremity surgery, attending orthopedic surgeon and senior scientist at Hospital for Special Surgery and professor of orthopedic surgery at Weill Medical College of Cornell University in New York.
Change in indications
The prototype for the current fourth-generation total wrist implants, the Universal Wrist Replacement (Integra LifeSciences), was initially implanted in the early 1980s. Since then, the design of modern total wrist implants has evolved. This evolution has been prompted by a greater understanding of wrist biomechanics, improved implant design incorporating porous ingrowth and solid bony fixation, as well as a recognition of factors that led to failure of early designs. Contemporary arthroplasty designs overcome many of the difficulties experienced by early generation designs. These include replication of the anatomic alignment of the distal radius, recreation of the axis of rotation of the wrist, maximizing bone stock with minimal bony resection, maintenance of the carpus incorporating screw fixation and porous ingrowth, replication of the geometry of the prosthesis during implantation with implant-specific rasps and broaches and improved patient selection.
With earlier generation prostheses, implantation was limited to elderly low-demand patients, typically ones afflicted with RA. The rationale for these limited indications was based on the high potential for failure due to limited component fixation. Current prostheses have addressed many of the earlier design flaws. Indications have changed and the population of patients that benefit from arthroplasty vs. arthrodesis has expanded. The ideal patient suited for contemporary arthroplasty is one with the potential for motion, who has a well-balanced wrist in the sagittal and coronal planes, has good tendon function, has supple soft tissue coverage and, most importantly, has adequate bone stock to allow for implantation and accommodation of screws for fixation of the carpal component. Patients must also understand some of the postoperative limitations of TWA because, even with contemporary designs and improved fixation, heavy repetitive loading or high-impact activities place the implant at a higher risk for failure.
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- Srnec JJ, et al. JBJS Rev. 2018;doi:10.2106/JBJS.RVW.17.00123.
Jeffrey A. Greenberg, MD, MS, is at the Indiana Hand to Shoulder Center in Indianapolis.