Abstract
PURPOSE: We developed a new intramedullary rod named Wrist Fusion Rod for total wrist arthrodesis in patients with rheumatoid arthritis experiencing a severely deteriorated and dislocated wrist. Key design features include the following: (1) a tubular pure titanium rod with an outer diameter of 4.5 mm and wall thickness of 1 mm, (2) a 1.5-mm guide pin ensures precise drilling into the third metacarpal, (3) the tubular design allows controlled deformation under load to achieve the desired angle, (4) a fin on the proximal part and a transverse set screw on the distal part prevent backout and rotation, and (5) a fully embedded rod does not protrude into interdigital space. The purpose of this study was to evaluate the outcomes of wrist arthrodesis using this new rod. METHODS: From 2007 to 2021, total wrist arthrodesis using this rod was performed in 53 wrists in 43 patients with rheumatoid arthritis. Preoperative radiographs of the wrist were in Larsen grade IV or V with palmar and/or ulnar dislocation. Clinical and radiographic assessments were performed. RESULTS: In total, 48 wrists in 39 patients (seven men and 32 women) were available for this study. The mean age was 66 years, and the mean postoperative follow-up period was 77 months. With the use of this new rod, the risk of complications, which were a concern in the past, was reduced. The wrist was fixed at 17° of extension, and disease activity, grip strength, range of pronation, and radiological parameters significantly improved. In the patient survey, overall satisfaction was high in patients with severe ulnar carpal shift. Complications occurred in eight wrists (17%), including rod breakage in one wrist, the third metacarpal cortical ballooning in two wrists, and delayed wound healing in one wrist. CONCLUSIONS: Total wrist arthrodesis with Wrist Fusion Rod is expected to provide for long-lasting pain relief and stability with severe wrist deterioration and ulnar carpal shift. The rods enhance surgical safety and precision, and ensure the desired fixed position. Fixation of the mobile third carpometacarpal joint would minimize micromotion and metacarpal cortical ballooning, eliminating the need for postoperative rod removal. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.