Total Wrist Arthroplasty

Rowena McBeath, MD, PhD

Annie Ashok, MD

Terri Skirven, OTR/L, CHT

None of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. McBeath, Dr. Ashok, and Dr. Skirven.

Introduction

Total joint arthroplasty has defined the modern era of orthopaedic surgery. In the wrist, total wrist arthroplasty (TWA), though innovative, has yet to match the successful patient outcomes provided by hip and knee arthroplasty. However, notwithstanding differences in joint anatomy, mechanics, and, thus, kinematics, novel TWA designs have proven promising for the appropriate patient.

Indications and Contraindications

As with many surgical interventions, the success of TWA depends on patient selection. The ideal candidate for TWA has painful, destructive arthritis of one or both wrists, and/or coexistent multilevel upper extremity arthritis. Patients must be willing to accept a low-demand lifestyle in return for a stable, pain-free joint with functional range of motion (ROM) and the ability to perform activities of daily living (ADLs) that require wrist motion such as writing, fastening buttons, and perineal care.

The primary indication for TWA is painful, debilitating pancarpal arthritis. TWA has traditionally been employed in patients with advanced rheumatoid arthritis, a disease that commonly affects bilateral wrists and multiple joints of the upper extremity. In addition, studies have shown that TWA is beneficial to patients with severe nonrheumatoid inflammatory arthritis, osteoarthritis, and posttraumatic arthritis. TWA is also indicated in patients with advanced avascular necrosis of the carpal bones.

TWA is contraindicated in those unable to adhere to strict activity limitations, such as physical laborers or patients who require the use of walking aids and must bear weight on their wrists. Other contraindications include active infection, a history of sepsis or osteomyelitis, a hand lacking neurologic function, rupture of the radial wrist extensors, and ligamentous laxity. Relative contraindications to TWA include immunosuppression, systemic lupus erythematosus, proximal row carpectomy, and other conditions resulting in poor carpal bone stock.

Procedure

Relevant Anatomy

The wrist moves in three planes of motion: flexion-extension, radial-ulnar deviation, and prono-supination. Normal ROM of the wrist includes volar flexion of 85° to 90°, extension (or dorsiflexion) of 80° to 85°, radial deviation of 20° to 25° and ulnar deviation of 30° to 35°. The movements of the wrist take place along an axis through the capitate, and pronation and supination occur about the distal radioulnar joint.

The mechanical axes of the wrist are oriented obliquely to the anatomic axes, with the primary mechanical direction of the wrist being radial extension and ulnar flexion. The ROM of the wrist that is required for most functional ADLs is flexion and extension of 30°, and ulnar and radial deviation of 10°, thus facilitating a hand position that contributes to fine motor control of the fingers and grip strength.

Technique

The surgical approach to TWA is similar across implants, with some variation based on the specific prosthesis used. Postoperative rehabilitation is similar across implants without any specific alterations according to the implant used (Figure 33.1).

Prior to surgery, radiographs of the wrist are used to template and estimate the size of the implant, as well as the amount of distal radius to be resected. The operation is performed on a hand table with the use of an upper arm tourniquet and either general or regional anesthesia. The arm and hand are prepped and draped in the standard fashion, and an Esmarch bandage is used to exsanguinate the limb. Loupe magnification is used for all dissection.

A longitudinal dorsal incision is made from the middle of the third metacarpal extending to 2 cm proximal to the Lister tubercle on the distal radius. Skin flaps are created and bleeding is controlled with a clamp and microcautery. Care must
be taken to protect the sensory branches of the radial nerve, which course over the anatomic snuffbox, and dorsal ulnar cutaneous nerve branches, which become dorsal distal to the ulnar styloid. The dissection is carried down to the extensor retinaculum, the third dorsal compartment is opened, and the extensor pollicis longus (EPL) tendon is released and radialized. Extensor tenosynovectomy is performed in all compartments.

Next, capsular flaps are elevated from the radius through a longitudinal incision based on the third metacarpal. Carpal resection is performed using rongeurs. The carpal guide is placed parallel to the longitudinal axis of the long finger metacarpal and stabilized with two 0.062-inch Kirschner wires (K-wires). The proximal carpal row, edge of the hamate, and proximal capitate head are resected according to each implant’s requirement. The carpal component is then trialed.

Figure 33.1 A, Photograph of an example of total wrist arthroplasty implants. B, Preoperative wrist radiographs of a patient with rheumatoid arthritis. C, Postoperative radiographs of a total wrist arthoplasty in a patient with rheumatoid arthritis.

Turning attention to the radial component, the wrist is then palmar flexed and a K-wire is driven into the center of the distal radius intramedullary canal and the position is confirmed by fluoroscopy. The distal articular surface of the radius is resected, broached, and trialed, paying close attention to protect the surrounding soft-tissue structures, including the volar radiocarpal ligaments. The wrist with trial carpal and radial components is then reduced to examine stability and ROM, both clinically and fluoroscopically.

The trials are then exchanged for implants, and screw fixation to the long finger metacarpal shaft and hamate is performed. After ensuring adequate ROM and stability, the wound is irrigated, the EPL is radialized, and the extensor retinaculum is repaired. The wounds are closed in a layered fashion and postoperative radiographs are obtained to confirm alignment of the prosthesis. The wrist is typically immobilized with a volar wrist neutral splint, and the hand is elevated to prevent and minimize swelling.

Complications

In addition to general complications of operative procedures, including bleeding and damage to nearby structures, many of the complications of TWA are related to the nature of the disease process. Infection is an especially severe problem, with the potential for substantial morbidity. Patients with rheumatoid arthritis may be particularly susceptible to infection because of the immunosuppressive effects of medical therapy for this condition.

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