Ring Avulsion Injury

This is a ring avulsion injury, a traction-degloving of the finger where the ring transmits a sudden axial force that strips the soft-tissue sleeve off the skeleton, tearing the vessels, nerves and tendons over a long segment even if the skin looks deceptively intact. I would assess the patient and the digit, document its perfusion, capillary refill, sensation and skeletal integrity, take radiographs, and classify it using the Urbaniak system: class I is adequate circulation with a soft-tissue injury only, class II is inadequate circulation needing microvascular repair, and class III is complete degloving or amputation; the Kay modification subdivides class II into arterial and venous and adds a class for bone injury and a class IV for complete amputation. Management follows the class. A class I injury needs soft-tissue and any fracture care but no vessel repair. A class II injury needs urgent microvascular revascularisation, and because the zone of vessel injury is far longer than it appears, I would debride the avulsed artery and vein back to healthy ends and bridge the gaps with interposition vein grafts rather than a tension repair, and repair nerves and cover soft tissue. A class III or complete amputation requires a decision between replantation and completion amputation: replantation is most worthwhile if the PIP joint and FDS are intact and the digit is clean with acceptable ischaemia time and a motivated patient, otherwise a well-fashioned completion amputation gives quicker reliable function. I would make this decision with the patient, considering his manual occupation, hand dominance and the fact that a stiff, insensate finger can impair overall hand function, and I would warn about the risk of late vascular failure in a replant.

The historical teaching was that complete (Urbaniak class III) ring avulsions should be treated by completion amputation, and although the evidence now shows that selected class III injuries can be replanted successfully, completion amputation remains the right choice in many cases. I would favour completion amputation when the avulsion is through or proximal to the PIP joint with loss of the FDS, because an intact PIP and FDS are the main predictors of a good functional replant; when the digit or vessels are severely damaged or contaminated, or there has been prolonged warm ischaemia; when the patient is a heavy smoker or has vascular disease that compromises microsurgical success; when the patient's occupation and hand dominance demand a quick, reliable, pain-free return of function; and when the affected finger is a single border or index digit whose stiff, cold-intolerant, insensate replant would actually impede the rest of the hand, as patients often bypass such a finger. The decision is shared with the patient, balancing the prolonged rehabilitation and uncertain outcome of replantation against the reliable function of a well-fashioned amputation. I would also warn that even a successful replant may be stiff, cold-intolerant or partly insensate and is at risk of late vascular failure.