Small Finger to Ring Finger Ray Transposition: Modern Surgical Technique and Case-based Review of the Literature

Ray transposition for central digital amputation has been performed following traumatic injury to the hand for decades. Small finger to ring finger ray transposition has been well described in the literature, with good functional and aesthetic outcomes reported. Originally described by Bunnell, the fourth metacarpal can be disarticulated and the fifth metacarpal base transposed with reconstruction of the intermetacarpal ligament allowing progressive closure between the third and fifth rays. However, osteotomy-based transpositions are utilized placing the osteotomy at the level of the metacarpal, followed by transposition and fixation of the small finger to the base of the ring finger metacarpal; or, by making an intracarpal wedge-osteotomy of the hamate with subsequent radial translocation of the entire small finger ray. Recent literature has suggested the intracarpal wedge osteotomy to be superior technically, and with less postoperative complications. However, for this somewhat uncommon reconstructive procedure, no high-level evidence exists to determine which of these techniques is truly more favorable. Here, we present an interesting case of ray amputation and transposition following an isolated fourth metacarpal traumatic firearm injury, and comprehensive modern surgical technique. Upon review of the literature, small to ring finger ray transposition has been shown to have acceptable functional and aesthetic outcomes regardless of the osteotomy technique used, and should be considered when the nature of presenting injury and the patient's lifestyle and postoperative expectations are appropriate.