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.