Ulnar Head Replacement and Related Biomechanics

Abstract

Up to 30% of patients after distal radius fractures suffer from ulnar-sided wrist pain. 1 This is manifested in the form of wrist pain, restricted movement, weakness, and instability, even after correct reduction of the fracture and bony union. The integrity of the distal radioulnar joint (DRUJ) is necessary for stability and load transfer from the forearm to the wrist. [2][3][4] Osteoarthritis of the DRUJ may occur after trauma due to a bony deformity, a ligamentous injury, or combination of both. 1,5,16 In the surgical treatment of osteoarthritis, "salvage operations" are often necessary, in which the ulnar head is resected partially or completely. 7-10 Numerous clinical studies have demonstrated a reduction of painful clinical symptoms for all these techniques. 11-14 Biomechanically, even a partial resection of the distal ulna destabilizes the wrist, and clinically, it may lead to instability of the distal ulnar stump and the radius. 15,16 Distal radioulnar impingement occurs because the distal support of the radius for rotation and the "cam effect" of the distal ulna have been ablated. As a result, instability of the DRUJ may again lead to restriction of motion and strength as well as to increased pain. [17][18][19] To reduce DRUJ instability, various "soft tissue stabilization operations" have been developed. The most common techniques are the pronator quadratus-interposition flap (Johnson procedure) 20 and the extensor carpi ulnaris (ECU)-flexor carpi ulnaris (FCU) tenodesis (Breen-Jupiter tenodesis). [21][22][23] Biomechanical studies, however, show that these procedures do not provide adequate stabilization of the distal ulna. 24 Ulnar head prostheses have also been developed to restore the integrity of the DRUJ, which has been shown experimentally 6 and clinically. [25][26][27][28] Keywords ► distal radioulnar joint (DRUJ) ► osteoarthritis ► arthroplasty ► ulnar head resection ► ulnar head prosthesis AbstractA stable distal radioulnar joint (DRUJ) is mandatory for the function and load transmission in the wrist and forearm. Resectional salvage procedures such as the Darrach procedure, Bowers arthroplasty, and Sauvé-Kapandji procedure include the potential risk of radioulnar instability and impingement, which can lead to pain and weakness. Soft tissue stabilizing techniques have only limited success rates in solving these problems. In an attempt to stabilize the distal forearm mechanically following ulnar head resection, various endoprostheses have been developed to replace the ulnar head. The prostheses can be used for secondary treatment of failed ulnar head resection, but they can also achieve good results in the primary treatment of osteoarthritis of the DRUJ. Our experience consists of twenty-five patients (follow-up 30 months) with DRUJ osteoarthritis who were treated with an ulnar head prosthesis, with improvement in pain, range of motion, and grip strength. An ulnar head prosthesis should be considered as a treatment option for a painful DRUJ.

Distal radioulnar joint arthroplasty with implants: a systematic review

“…In ten of the 18 series, no useful information could be retrieved, whereas eight papers reported osteolysis without frank loosening of the implant components. This radiolucency or osteolysis at the distal ulna stump was reported to be 90%, and 100% of cases in Type 2 implants in two studies, 24,30 and 30% for Type 3 implants, in four studies with a progressive tendency. In Type 2 implants radiological DRUJ instability was reported in three papers and observed in 21% of cases if we calculate all the cases reported (Fig.…”

“…In four papers, grip strength was significantly improved, 14,18,29-30 whilst in another four papers, grip strength was not reported.…”

“…13-14,17-18,24,26-30 Two of these papers showed a statistical improvement in pain in 80% of cases. 26,27 The other eight papers did show improvement in the VAS for pain, but it was either not statistically significant, or a statistical analysis was not performed.…”

Arthroplasty of the distal ulna distal in managing patients with post-traumatic disorders of the distal radioulnar joint: measurement of quality of life

“…Biomechanical studies have presented statistically significant evidence showing that the prosthesis favors stability, diminishes impaction on the radius and recovers pronation–supination, in comparison with other salvage techniques cited above. 8 , 12 …”

Distal Ulna Leiomyosarcoma Treated with Custom Polymethylmethacrylate Prosthesis with a 4-Year Follow-up

“…However, most of them are designed to be used in patients with intact soft tissue and stabilizing ligaments at the DRUJ. These devices, therefore, are not appropriate for use in patients who have undergone resection of the DRUJ because anteroposterior stability is not fully restored and suturing soft tissue limits mobility [20,28,29,31]; reinsertion of the soft tissues at the metallic head may be difficult in patients who have undergone several surgical interventions, and to improve the adaptation of the implant, it may be necessary to remodel and deepen the sigmoid notch of the radius [27].…”