This study investigates the outcomes of trapeziometacarpal joint reconstruction using a massive iliac crest graft in patients with loosening of the cup of a ball-and-socket prosthesis. Seven patients, aged 49–75 years, underwent revision surgery between November 2017 and January 2021 due to aseptic cup loosening of ball-and-socket implants. The surgical approach involved a modification of a previously described technique of harvesting a structural iliac crest graft and implanting it with the prosthetic cup component to reconstruct the medullary cavity of the trapezium. Postoperative assessments showed improvements in pinch and grip strength, while patient-reported outcomes, including Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) and Visual Analog Scale (VAS) scores, revealed significant reductions in pain and disability. Two patients required further revision surgery, including one technique failure. No acute complications or infections occurred. These results suggest that iliac crest graft reconstruction may be an effective salvage procedure for cup loosening in TMC prostheses with an intact trapezium cortex, providing favorable functional outcomes and pain relief.

IV.