ORIGINAL ARTICLE Treatment of Displaced Proximal Fifth Metatarsal Fractures Using a New One-Step Fixation Technique Thomas C. Koslowsky, MD, Thomas Gausepohl, MD, Konrad Mader, MD, Steffen Heck, MD, and Dietmar Pennig, MD Background: Fractures of the tuberosity of the fifth metatarsal are common after foot twisting injuries, and operative treatment is recommended in cases of displacement. The purpose of this study was to report the radiologic outcome and clinical results of displaced fractures of the tuberosity of the fifth metatarsal treated using fine-threaded K-wires (FFS). Methods: In 3 years’ time, in a total of 35 cases, patients had an initial fracture displacement of more than 2 mm for isolated extraarticular fractures and an involvement of the cuboidal joint surface of more than 30%. After 15 months to 60 months (mean, 30.6), 32 of these patients participated in a clinical follow-up examination and questionnaire according to a clinical rating system for midfoot fractures. Radiologic outcome measurements were the remaining postoperative intraarticular step off and the healing time. Results: The mean midfoot scale score was 96.5 points. All the patients returned to prior activities after operative treatment. Seven patients reported minor pain during longer periods of walking. One patient with secondary wound healing experienced frequent pain. Radiologically, in 32 of 35 patients, there was a remaining step off of less than 1 mm and in three patients less than 3 mm. All fractures except one healed within the first 3 months to 6 months. Conclusion: Operative treatment of displaced proximal fifth metatarsal fractures using the FFS system leads to a good clinical and radiologic outcome. The FFS system provides a new treatment option for this fracture type. Key Words: Fifth metatarsal fractures, FFS, One-step fixation system. (J Trauma. 2010;68: 122–125) A twisting injury to the foot may result in a fifth metatarsal fracture, a common fracture in outpatient orthopedic settings. 1 Topographically, these fractures are subdivided into fractures of the head, subcapital, mid-shaft, and basal frac- tures. 2 Proximal or basal fractures present as injuries of the metaphyseal-diaphysial junction (Jones fractures) or of the tuberosity. 3 Conservative treatment is recommended for non- displaced fractures of the tuberosity, and open reduction and internal fixation (ORIF) is recommended for a displacement of more than 2 mm with more than 30% of the cuboidal joint involved. 2,4 The use of fine-threaded K-wires (FFS; Orthofix, Bus- solengo, Italy) in small fragment fixation has been reported previously and its clinical use was shown in several parts of the body. 5–8 Here, we present the first clinical results, radio- logic outcome, and operative technique in treatment of dis- placed fractures of the fifth metatarsal using the FFS system. METHODS During a period of 4 years, a total of 35 patients (mean, age 48.4; range, 24 – 88 years) with a displaced fracture of the tuberosity of the fifth metatarsal have been treated using the FFS system (Fig. 1). Metaphyseal-diaphysial junction frac- tures (Jones fractures) have been excluded from this series, because 3.5 mm malleolar screws were used for this type of fracture. There were 13 male and 22 female patients. Twenty- nine of the 35 patients, belonging to the older population, had twisting injuries to the ankle. Five patients had direct trauma to the foot and one patient was treated for a stress fracture to the tuberosity. Diagnosis was performed by clinical exami- nation followed by roentgenogram of the foot in three direc- tions. Indication for operative treatment was present when the fragment displacement was more than 2 mm and the fracture involved more than 30% of the joint surface to the os cuboideum. Three of the 35 fractures were extraarticular with a displacement of the whole articular block with a dislocation of more than 5 mm and a fracture line running toward the amphyarthrosis of the fourth and the fifth metatarsal. In addition to fragment displacement, we saw a rotation of the fragments in these fractures during studies of the preoper- ative roentgenograms. Eight of the 35 patients had more than two intraarticular fragments. The operative procedure was performed in a mean of 8 days (1– 45) after trauma as a planned procedure. We saw one patient with an addi- tional lateral malleolar ankle fracture treated with standard plate fixation. A tourniquet was used in all operations at our center. A 3-cm lateral skin incision was performed on the most prom- inent part of the proximal fifth metatarsal. The proximal part of the fifth metatarsal and the insertion of the peroneus brevis tendon were revealed and the branches of the sural nerve were protected. After the detection of the fracture gap, the fracture hematoma was spilled out and the dislocated frag- ment was reduced by a hook retractor (Fig. 2, A). In addition to the direct view, fluoroscopy was used to assess the accu- racy of reduction during FFS fixation. Depending on the fragment size, a 2.2 mm or a 1.6 mm fine-threaded K-wire Submitted for publication July 17, 2008. Accepted for publication March 6, 2009. Copyright © 2010 by Lippincott Williams & Wilkins From the Department of Orthopedics, Traumatology, Hand and Reconstructive Surgery, St. Vinzenz-Hospital, Cologne, Germany. Address for reprints: Thomas Christian Koslowsky, MD, Joseph Teusch Strasse 7, D-50935 Cologne, Germany; email: tkoslowsky@web.de. DOI: 10.1097/TA.0b013e3181a8b355 122 The Journal of TRAUMA ® Injury, Infection, and Critical Care • Volume 68, Number 1, January 2010