Custom 3D Implant for Hemiarthroplasty of the Third Metacarpal in a Giant Cell Tumor of bone: Functional Outcomes and Hand Stability

Abstract

Giant cell tumor (GCT) of the hand is a rare benign but locally aggressive bone tumor with high recurrence rates. It is commonly treated by curettage with cementation or bone grafting. However, reconstruction after en bloc resection of metacarpal GCT remains challenging, particularly in young patients. Conventional options such as allografts or standard prostheses are associated with notable complications and functional limitations. Custom- made 3D-printed implants have recently emerged as a potential alternative, although current evidence is limited. We report the case of a 19-year-old woman with a recurrent GCT of the third metacarpal following initial curettage and cementation. After neoadjuvant denosumab therapy, an en bloc resection of the third metacarpal was performed. Reconstruction was achieved using a patient-specific 3D-printed titanium hemiarthroplasty featuring an intramedullary stem, screw fixation, porous surfaces for osseointegration, and dedicated structures for ligament reinsertion to ensure hand stability. Early postoperative mobilization was allowed. At mid-term follow-up, the patient demonstrated excellent functional recovery, high total active motion, minimal pain, and no complications, implant instability, or tumor recurrence. Custom-made metacarpal hemiarthroplasty appears particularly suitable for reconstruction of central rays, where transverse stability is supported by adjacent structures. This case supports patient-specific 3D-printed hemiarthroplasty as a promising reconstructive option, providing favorable early functional outcomes while preserving joint biomechanics. Further studies are needed to assess long-term durability.