[Radioulnar impingement after distal ulnar resection and ulnar head hemiresection interposition arthroplasty (Bowers procedure). An experimental biomechanical study]

The semiconstrained DRUJ prosthesis: blessing or curse?

PURPOSE

There are numerous operative procedures to treat osteoarthritic changes or a significant instability of the distal radioulnar joint (DRUJ). The key problem of most methods is the destabilization of the forearm leading to secondary painful impingement between the radius and ulna, as well as a significant limitation of forearm rotation. The Aptis-Prosthesis designed by Scheker represents a complete substitute for the DRUJ. It is mostly used after the failure of various treatment options to solve the primary problems (arthritis, instability). We have used this type of prosthesis mostly after multiple operative treatments for more than 25 years.

METHODS

In the following retrospective study, we analyzed the data of patients that received an Aptis-prosthesis between 2016 and 2021. We have implanted this prosthesis in 13 cases (11 female, 2 male). Routinely, we document the clinical outcome concerning range of motion (ROM), grip strength, and pain according to numeric rate scaling (NRS) after more than 12 months (month 12-24). In addition, complications, osseous changes, and the rate of loosening of the prosthesis were registered. Furthermore, DASH-Score and patients ' satisfaction were evaluated. Also-as with other implants-follow-up x-rays were performed.

RESULTS

Removal or significant revision of any of the prostheses was not needed. The ROM was 68.1° ± 19.7° for pronation and 72.3° ± 20.9° for supination, grip strength amounted to 27.7 kg ± 11.0 kg equaling 83% of the contralateral side. NRS was 0 at rest and 1.2 (0-2) under weight-bearing. A lysis margin of the radial tap was noted in the radiological examination in 2 patients but without any signs of loosening. The DASH-Score added up to 31.8 ± 13.8 (13-55). All patients were satisfied or very satisfied having this implant.

CONCLUSION

The semiconstrained Aptis-prosthesis is a safe and efficient treatment option after failed DRUJ surgeries. It is striking that of the 20 implanted prostheses no significant revision or explantations were necessary over a period of 25 years.

[Endoprostheses of the distal radioulnar joint]

BACKGROUND

A stable distal radioulnar joint (DRUJ) is mandatory for the rotation and load transmission in the forearm and wrist. Salvage procedures such as the Darrach operation, Bowers arthroplasty, and the Kapandji-Sauvé procedure include the potential risk of dynamic radioulnar instability and impingement, despite stabilizing techniques addressing the soft tissues.

PROSTHESES

In an attempt to stabilize the distal forearm mechanically following ulnar head resection, various endoprostheses have been developed to replace the ulnar head. These prostheses can be used for secondary treatment of persistent complaints and unsatisfactory results after ulnar head resection, but also in the primary treatment of osteoarthritis of the DRUJ. Based on promising results concerning improvement in pain, range of motion, and grip strength, with proper indications ulnar head prostheses should be considered as a valuable treatment option for osteoarthritis of the DRUJ.

Disorders of the distal radioulnar joint

The distal radioulnar joint is responsible for stable forearm rotation. Injury to this joint can occur following a variety of mechanisms, including wrist fractures, ligamentous damage, or degenerative wear. Accurate diagnosis requires a clear understanding of the anatomy and mechanics of the ulnar aspect of the wrist. Injuries can be divided into three major categories for diagnostic purposes, and these include pain without joint instability, pain with joint instability, and joint arthritis. New advancements in imaging and surgical technique can allow for earlier detection of injuries, potentially preserving joint function. In this article, the authors review the pertinent anatomy, biomechanics, and major abnormality involving the distal radioulnar joint.

A new total distal radioulnar joint prosthesis: functional outcome

PURPOSE

To present the evolution of design and the short-term functional outcome of our distal radioulnar joint (DRUJ) prosthesis. This total DRUJ prosthesis differs from others in that it consists of 2 parts and attains bony fixation by its hydroxyapatite coating.

METHODS

Nineteen patients received a DRUJ prosthesis after a failed Darrach procedure (n = 10), Sauvé-Kapandji procedure (n = 7), trauma (n = 1), or DRUJ synovitis (n = 1). Indications for the placement were decreased grip, decreased forearm motion, and pain due to ulnar impingement syndrome and instability of the distal ulna. Seven prostheses were removed, 5 due to loosening, 1 due to continuing pain, and 1 at the request of the patient. The 5 prostheses that loosened were an intermediate prototype no longer in use. In 12 remaining cases, range of motion, grip strength, and pinch strength were measured, and patients completed the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. Pain was assessed with the visual analog scale (range, 0-10). A paired t-test was performed to assess the significance of the difference between preoperative and postoperative measurements.

RESULTS

Statistically significant improvements were seen in forearm pronation, from an average of 79° to 88°; grip strength, from an average of 10 kg to an average of 16 kg; and visual analog scale score, decreased from a mean of 5.3 to a mean of 3.5. The distal ulna was clinically stable in all 12 patients who retained the prosthesis.

CONCLUSIONS

The intermediate prototype had a high failure rate, 5 out of 5. The early results for the current prosthesis prototype show clinical improvement. Based on these results, we conclude that this prosthesis offers a new treatment option for ulnar instability after distal ulnar resection.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.