Intramedullary Insetting of Silicone Implant for Lateral Stability in Distal Interphalangeal Joint Arthroplasty

Silicone implant arthroplasty is an alternative surgical intervention for painful and deformed osteoarthritis of the distal interphalangeal (DIP) joints. DIP joint stability is essential for hand function; however, it carries a potential risk of postoperative joint instability. To address this concern, an intramedullary implant insetting method was used to maintain joint stability by minimum resection of the head of the middle phalanx and preserving the collateral ligament. In the new method, the length of the bone excision was limited to maintain the lateral cortical bone with the insertion of the collateral ligament, and the medullary cavity of the middle phalanx was partially removed to intentionally set the hinge part of the silicone implant in the medullary canal. Between 20 digits of the conventional approach and 23 digits of the intramedullary insetting method, there were no significant differences in patient demographics (ie, age, affected hand, and finger), and clinical characteristics (ie, active DIP joint arc, DIP joint extension loss, grip strength, visual analog scale, and Quick Disabilities of the Arms, Shoulder and Hand questionnaire score) before and over 6 months after surgery. However, postoperative joint instability was significantly lower with the intramedullary insetting method, with a significantly shorter length of bone excision of the middle phalanx. This new approach is more beneficial than the conventional approach for preventing postoperative joint instability.