Repair of Thumb Metacarpophalangeal Joint Ulnar Collateral Ligament Injuries With Microanchors Ashraf N. Moharram, MD Introduction: Ulnar collateral ligament (UCL) injuries of the metacarpophalangeal (MCP) joint of the thumb are common. Complete rupture can be a debilitating injury, resulting in decreased grip and pinch strength. Purpose: The present study evaluated prospectively the functional results of 27 patients who had open repair of the UCL of the thumb using microanchors either acutely or delayed (up to 9 weeks postinjury). Methods: Through a standard S-shaped incision over the dorsoulnar aspect of the thumb, one or two 1.5-or 1.3-mm microanchors are fixed to the base of the proximal phalanx in the footprint of the avulsed ligament and used to suture the proximally based f lap after temporary pinning of the MCP joint. Results: Stability, range of motion, pinch grip, and radiographs were evalu- ated at least 16 months after surgery. The mean time off work was 10 weeks. All patients had equal stability and normal pinch grip when comparing with the untreated thumb, allowing all patients to return to preinjury activities, in- cluding sports, except one (96% of cases). At final follow-up, radiographs showed no implant complications, no osteoarthritic changes in MCP joints, and stress testing showed that all patients had normal stability in the treated thumb when compared with the untreated thumb. Only 2 patients complained of a lumpy swelling at the ulnar aspect of the MCP joint, one of which was tender. Conclusions: Repair of UCL of the MCP joint of the thumb with this tech- nique is an effective, durable, and safe method to allow restoration and maintenance of a stable, pain-free thumb. (Ann Plast Surg 2013;71: 500Y502) U lnar collateral ligament (UCL) injuries are the most common injury of the thumb metacarpophalangeal (MCP) joint. 1 The mechanism of injury is sudden, severe radial deviation (abduction). Complete rupture of the UCL of the thumb MCP joint can be a debilitating injury, resulting in decreased grip and pinch strength, thumb discomfort, and/or secondary osteoarthritis. 2 The ligament is usually torn from the distal attachment but sometimes there are proximal or intrasubstance ruptures. 3Y5 In most of these injuries, the distal portion of the ruptured UCL is displaced proximally and is entrapped superficial to the proximal edge of the intact adductor aponeurosis (Fig. 1). This prevents healing of the ruptured ligament and is known as Stener lesion. Stener lesions are reported to be present in 64% to 87% of complete ruptures of UCL necessitating surgical treatment. 4,6 PURPOSE The present study evaluated prospectively the functional re- sults of 27 patients who had open repair of the UCL of the thumb MCP joint using microanchors for a minimum of 16 months. METHODS Twenty-seven patients with acute or delayed (after 3 weeks postinjury up to 9 weeks) presentation of UCL injuries of the thumb were included in this study. Most patients included in this study (21 patients) presented after 3 weeks postinjury. All patients had a clear history of a valgus-directed traumatic incident that caused the rupture. There was pain, swelling, ecchy- mosis, and tenderness at the ulnar aspect of the MCP joint of the thumb, and in some patients (especially in cases with delayed pre- sentation), a lump or mass is palpable in this area which might be indicative of a Stener lesion. Valgus stress testing is performed with the thumb held in full extension and 30 degrees of f lexion. 4,6Y8 Standard posteroanterior, lateral, and oblique radiographs were obtained in all patients with suspected UCL injury to identify an accompanying avulsion or condylar fracture and sometimes volar and radial subluxation of the proximal phalanx can be noted. The presence of a 30-degree overall valgus laxity or a 15- degree difference from the contralateral thumb in absence of a clear end point to valgus was also considered as an indication of complete ruptures. 9Y11 If there is a firm end point to valgus stress testing, a partial UCL tear is diagnosed and nonoperative treatment is favored. In cases where testing valgus instability is too painful or a firm end point is difficult to feel, the MCP joint is infiltrated with 2 mL of lidocaine to improve reliability of clinical testing as described by Cooper et al. 12 Although there is concern regarding stress testing in the presence of a nondisplaced fracture, it is relatively safe to assume that if the initial force of the injury did not displace the fracture, additional stress testing is not thought to be sufficient to displace the fracture. 2,9 If the MCP joint is unstable to stress or the avulsed fragment is displaced or malrotated or the proximal phalanx is subluxed, it has been shown that operative treatment is necessary. 10 A standard lazy S-shaped incision over the dorsoulnar aspect of the thumb is used. The adductor aponeurosis is identified and separated from the joint capsule. For the more common distal avul- sions, a proximally based flap containing the UCL is raised and distally based f lap containing the UCL remnants, capsule, and soft tissue is raised off the ulnar edge of the proximal phalanx. A tem- porary transosseous k-wire is used to hold the MCP joint in a reduced position while the ligament is repaired and tensioned then removed at the end of the procedure. One or two 1.5- or 1.3-mm microanchors are fixed to the base of the proximal phalanx in the footprint of the avulsed ligament and used to suture the proximally based flap (Fig. 2) after temporary pinning of the MCP joint. The distal flap is now secured on top of the repair using the same sutures from the anchor. In patients with avulsion fractures, small fragments are typ- ically excised and the ligament is repaired back down to the bone with the same technique, whereas larger fragments are sometimes retained and incorporated into the repair (Fig. 3). 11 Only 2 cases in our series showed proximal avulsions and were treated similarly, but anchors were inserted into the metacarpal head. None of our cases had a true midsubstance tear and, in all patients, even with delayed presentation, the ligament was identifiable and repairable. Tears in the volar plate and dorsal capsule are identified and repaired, if present especially in cases with subluxation of the proximal phalanx. In the 25 cases with distal avulsions of UCL of the thumb, 19 patients were found to have Stener lesions where the distal portion of HAND SURGERY 500 www.annalsplasticsurgery.com Annals of Plastic Surgery & Volume 71, Number 5, November 2013 Received April 24, 2013, and accepted for publication, after revision, June 21, 2013. From the Department of Orthopedic Surgery, Faculty of Medicine, Cairo Univer- sity, Cairo, Egypt. Conflicts of interest and sources of funding: none declared. Reprints: Ashraf N. Moharram, MD, Department of Orthopedic Surgery, Faculty of Medicine, Cairo University, Cairo, Egypt. E-mail: dr.amoharram@gmail.com. Copyright * 2013 by Lippincott Williams & Wilkins ISSN: 0148-7043/13/7105-0500 DOI: 10.1097/SAP.0b013e3182a1adba Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.