Creation of a Four-Joint Finger after Second Toe-to-Digit Transplantation: Restoration of Form and Function

Second toe to digit transplantation is an established method for hand reconstruction after digit loss. The proximal phalanges of the hand and toe are usually trimmed to match the length found in the uninjured digital proximal phalanx. This results in a functional but short digit relative to the opposite hand, since the middle and distal phalanges of the toes are significantly shorter than those in the hand. Creation of a digit symmetric in length to the opposite hand results in a relatively long proximal phalanx (PP) and poor composite fist formation. The author presented such a case involving bilateral second toe-to-digit reconstruction , combine with secondary arthroplasties to achieve composite fist formation.

The patient sustained index and long finger amputations after a crush avulsion injury to his right dominant hand. He underwent bilateral toe-to-hand transplantation to reconstruct the digits to their original length. This created digits with relatively long proximal phalanges without the ability to form a composite fist. Secondary arthroplasty was performed at the level of bony union to allow a greater flexion arc and composite fist formation.

Arthroplasty was successful at each transplant. The arthroplasty at the long finger was complicated by recurrent subluxation due to a subluxed flexor tendon. This was corrected with A2 pulley reconstruction. The prostheses added 35 to 45 degrees of motion to the digits, resulting in a total active range of motion greater than 225 degrees, and the ability to form a composite fist.

Second toe-to-digit transplantation can be utilized to restore both function and aesthetic length, when combined with secondary arthroplasty. Caution must be used when the injury results in disruption of the aligning tendon pulleys, since no native joint capsule or stabilizing ligaments support the prosthesis.