Medium-Term Outcomes for Amandys Implant: A 5-Year Minimum Follow-Up of 63 Cases

Abstract

Background Amandys is a pyrocarbon interposition implant used as a therapeutic alternative to total wrist fusion (TWF) or total wrist arthroplasty (TWA) in painful and disabling extensive destruction of the wrist. Objective To review mid-term outcomes in a continuous prospective series of patients who underwent wrist arthroplasty Amandys with a minimum follow-up of 5 years. Methods Clinical evaluation included a satisfaction survey, pain, two functional scores, the short version of the Disabilities of the Arm, Shoulder, and Hand (QuickDASH) and the Patient-Rated Wrist Evaluation (PRWE), active wrist mobility, and grip strength compared with the contralateral side. Radiological evaluation was used to detect implant subsidence, carpal migration, bone lysis, or implant malposition. All per- and postoperative complications were collected. Results Fifty-nine patients (63 procedures) were evaluated with a mean follow-up of 7 years; 57% of the patients were males, and the mean age was 58 years. Among the patients, 90% were satisfied or very satisfied. Pain was significantly improved, with a gain of 4/10 ( p < 0.001). Functional outcomes also improved between the second and fifth year of follow-up. Active mobility was preserved and grip strength was significantly improved by 7 kg ( p < 0.001). No implant subsidence or carpal migration was observed. Ten patients (11.9%) underwent revision surgery for conflict (1%), rotation (6%), or implant dislocation (5%). All complications and revisions occurred early with no new events after 1 year of follow-up. Discussion Mid-term clinical and radiological outcomes were stable with improvement of functional scores. The survival rate was comparable to that reported for TWF with conserved mobility. We report fewer complications compared with those reported for TWA or TWF. Early instability of the implant was the main etiology of the revisions. Repositioning of the implant was successful. No conversion to TWA or TWF was necessary. Conclusions Mid-term outcomes of the Amandys implants were encouraging. Patients conserved good wrist motion with improved strength and functional scores. The implant was well tolerated. Functional outcomes continue to improve with the follow-up. The survival rate remains stable after 2 years. The level of evidence of this study is IV (therapeutic case series).

Keywords: Amandys; interposition; osteoarthritis; pyrocarbon implant; wrist arthroplasty.

Fig. 1

Height of the radial epiphysis. a  = distance between two lines perpendicular to the axis of the radius ( dotted line ), one passing through the proximal part of the ulnar notch of the radius and the other through the distal pole of the implant.

Fig. 2

Kaplan–Meier plot.

Fig. 3

A 38-year-old man at 9.5-year follow-up for his left wrist intervention for Kienböck's disease stage IV. ( A ) 1 month postoperative X-rays with implant rotational instability; ( B ) X-rays 1 month after revision; ( C ) X-rays at 9.5-year follow-up.