Bone Remodeling after Ulna Head Replacement in Distal Radioulnar Joint Arthroplasty: A Radiographic Comparison between a Partial and a Total Ulna Head Concept

Abstract

Background Ulna head arthroplasty has become an eligible solution for injury or disease in the distal radioulnar joint. Bone resorption beneath the prosthetic head is often reported, but mechanism poorly understood. Purpose The aims were to evaluate bone remodeling and radiological instability in two conceptually different distal radioulnar joint arthroplasties: the total and the partial ulna head replacement. Patients and Methods We conducted a retrospective radiographic assessment of 51 ulna head arthroplasties; 26 Herbert ulna (total ulna head replacement) and 25 First Choice (partial ulna head replacement), to analyze periprosthetic bone resorption and radiologic instability. Intraoperative/immediate postoperative and 1-year radiographs were reviewed by two independent assessors. The radiographic follow-up averaged 13 (10–17) months. The size of the stem in relation to the diameter of the ulna (filling ratio) was measured on the intraoperative/immediate postoperative radiographs. Bone resorption beneath the collar of the prothesis was measured on the 1-year radiographs and expressed as a bone resorption index (BRI) between the length of the resorption and the length of the implant stem. Radiological stability was measured on both the preoperative and the 1-year lateral radiographs. Results The total ulna head prothesis presented with more extensive bone resorption beneath the prosthetic head than the partial ulna head prothesis at 1-year post surgery (p <0.001). The filling ratio did not influence the 1-year bone resorption and there was no difference regarding radiological instability between the two prosthetic designs. Conclusion The pattern of bone adaptions after an ulna head prothesis may differ due to design and concept of the prosthesis.

Total Wrist Replacement: State of the Art, Challenges and Pitfalls: A Comparative Review

“…A newest study revealed that elevated serum titanium values are frequently found with the use of the Universal2 and Freedom being associated with often asymptomatic PPO in several patients, but the risk of loosening increased in implants older than 6 years, more than five PPOs, and serum titanium values between 26 to 31 µg/l [83]. PPO are commonly observed as well in 90% of cases one year after UHR around the collar of the uHead with it into the diaphysis pressfit inserted porous titanium coated stem (also found with all other UHR types), and PPO stabilized within three years postoperatively as well (Figures 2C/D, 5A3, 6A/C2 and 8C) [90][91][92]. Noted that the uHead including its option for total DRUJ replacement was withdrawn from the the marketplace by the company stryker (USA) in 2021 (prior offered by Small Bone Innovations / USA, financial interests?…”