Reimplantation of ring avulsion amputation of finger: intraoperative challenges and rehabilitation outcomes

Abstract

© BMJ Publishing Group Limited 2021. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A 14yearold teenager presented with a ring avulsion amputation of his right ring finger at the head of the proximal phalange in November 2020 as shown in figure 1. This injury was sustained as his metal ring was caught on a spike while jumping from a 12feet school fence. On arrival, the amputated digit was wrapped in a saline 0.9% soaked gauze and then placed into a plastic bag, which was immersed in a container with water and ice. With a cold ischaemic time of less than 2 hours and following discussion with the patient and his family, replantation was opted for. Intraoperatively, the proximal phalanx was reduced and fixed in position with a single Kirschner wire (Kwire). Fortunately, due to the fracture orientation, a second antirotational Kwire was not needed. It was noted that the flexor digitorum profundus (FDP) tendon was avulsed at the insertion point of the distal phalanx and the flexor digitorum superficialis (FDS) tendon was avulsed from the forearm with muscle cuff visible. The distal aspect of the FDS was transferred to the FDP tendon as reinsertion of the FDP would be too disruptive to blood supply. The flexor tendon repair was performed with a Pulvertaft weave technique. As for the extensor tendon, the central slip was repaired with a 4–0 prolene mattress suture. The distal digital radial artery and nerve were avulsed and not viable, so their proximal ends were used as crossovers to connect to the digital ulnar artery (10–0 nylon) and nerve (8–0 nylon), respectively. Two dorsal veins were repaired with 10–0 nylon for venous drainage. A split skin graft (SSG) was taken from his right thigh to cover the skin defect following skin closure. Postprocedure, the patient was observed closely on the ward for 5 days. His finger was well perfused, with good take of the SSG on discharge. His followup protocol was as per the British Society for Surgery of the Hand (BSSH) standards of care, with regular support from hand therapists. His hand therapy regime included support therapy early on while the digit was immobilised, subsequently moving to block and strengthening exercises after about 2 months. At the 1month followup, the proximal interphalangeal joint (PIPJ) was stiff. Overgranulation was also noted at the graft site, which was treated effectively with cautery (figure 1). At 6 months, he demonstrated good passive flexion at the PIPJ down to 70° with a spongey end point. At 9 months, the replanted finger was sensate to temperature and the PIPJ had full range of passive movement. Active flexion was still poor and he is scheduled for flexor tendon tenolysis±shortening of tendon to further improve function. Concurrently, he is also undergoing therapy with regards to the psychological effects of this trauma. Amputated digits are devoid of muscles and can survive up to 12 hours of cold ischemia. A common error in the preservation of an amputated part is to expose it to ice directly, which may cause a cold injury. Proper preservation of the amputated digit at the scene (wrapped with moist gauze,