Interposition arthroplasty for osteoarthritis of trapezio metacarpal joint: results of a modified incision and technique of interposing with early mobilisation.

Sixty flexor carpi radialis (FCR) tendon interposition arthroplasties were done using a modified incision from Froimson's approach for osteoarthritis (OA) of thumb carpo metacarpal joint (CMCJ) The tendon was made to resemble an anchovy fillet to preserve pillar length (average 7.5 mm). There was no incidence of injury to the superficial branch of the radial nerve. Graded mobilisation was commenced at two weeks. Our average follow-up for five and a half years shows good results, viz. pain relief (100%), power grip (21 kg), pinch grip (4.2 kg), tripod grip (5.5 kg), key grip (6.5 kg), ability to touch base and tip of little finger (91.6%) and (96.6%), respectively. Activities of daily living (ADL) without pain in turning a key (96.7%), opening jar top (100%), bottle top (93.4%), wringing cloth (86.7%), and using scissors (88.4%). None of them suffered reflex sympathetic dystrophy (RSD) and mobility was almost equal to the non-operated hand. Our experience with this modified incision and technique of interposing with early mobilisation has shown good functional outcome with no significant operative or postoperative complications.