85 Failed Bowers’ Arthroplasty: Ulnar Head Prosthesis
85.1 Patient History Leading to the Specific Problem
A 46-year-old man presents with persisting ulnocarpal pain, reduced forearm rotation, and the feeling of instability of the distal ulnar stump after a partial ulnar head resection was performed 3 months before in an orthopaedic-oriented outside department at the right hand.
Three years ago, the patient suffered from a distal radius fracture with an additional scaphoid fracture. Despite several operations, the scaphoid fracture did not heal properly and a painful osteoarthritis of the wrist developed. Therefore, total wrist fusion was performed elsewhere. Radiocarpal pain could be improved, but ulnocarpal complaints persisted through a severe osteoarthritis of the distal radioulnar joint (DRUJ). A Bowers hemiresection arthroplasty was performed with ancillary decompression of distal ulnar nerve in loge de Guyon. ▶Fig. 85.1 shows X-rays of the affected right wrist after the last operative intervention including a partial ulnar head resection.
85.2 Anatomic Description of the Patient’s Current Status
For the stability of the DRUJ, the contact between the ulnar head and the sigmoid notch is essential. Without that condition, the force transmission of the wrist, especially in transversal direction, is dysfunctional. A painful impingement of the ulnar stump against the radius is typical sequelae (▶Fig. 85.2). In the presented case, hoisting of objects in orthogonal direction to the axis of the forearm was extraordinarily painful. For example, simple grip strength testing using a Jamar dynamometer (Saehan Corporation, Changwon, South Korea) was not possible preoperatively because of pain when holding the device. Without osteochondral support, the triangular fibrocartilage complex (TFCC), the capsuloretinacular flap, or other surgical options cannot stabilize the forearm properly. Hence, the feeling of instability of the former DRUJ is a frequent problem after ulnar head resection. In the presented case, forearm rotation was also restricted to 45–0-55 degrees for supination/pronation. Of course, this was an especially remarkable handicap after total wrist fusion (▶Fig. 85.3).
85.3 Recommended Solution to the Problem
The replacement of the ulnar head by prosthesis is a well-established procedure for failed partial or complete ulnar head resection arthroplasty. The therapeutic goal is to restore the anatomic conditions of the DRUJ, stabilize the parallel movement of radius and ulna, and facilitate pain-free forearm rotation. The implant (Herbert prosthesis, KLS Martin, Tuttlingen, Germany) is a modular system with porous titanium shafts, collars of different lengths, and ceramic heads, available in three sizes each. The shaft osteo-integrates without the use of bone cement. Hemireplacement of the joint is sufficient, as it was shown that sigmoid notch remodels by itself over time in most cases (▶Fig. 85.4). Of course, a nonhinged prosthesis needs external soft-tissue stabilization. That is realized by an ulnar-based, capsuloretinacular flap. Longitudinal instability of the forearm, for example, following an Essex-Lopresti injury or resection of the radial head, and soft-tissue or ligamentous insufficiencies are contraindications for the use of this kind of prosthesis.
Fig. 85.1 (a, b) X-ray images of the right wrist after total wrist fusion and partial ulnar head resection. At rest, the ulnar stump is in correct position.
85.3.1 Recommended Solution to the Problem
• Replacement of the ulnar head with a distal ulnar (Herbert) prosthesis.
• Stabilization of the prosthesis and the reconstructed v by an ulnar-based, capsuloretinacular flap.
• The sigmoid notch does remodel in most cases so that no surface replacement is necessary despite osteoarthritic changes.
