A Prospective Randomized Trial Comparing Dual Mini-Fragment Plating to Single Precontoured Plating of Acute Midshaft Clavicle Fractures: A Pilot Study

Midshaft clavicle fractures have traditionally been treated non-operatively with immobilization in a sling or a figure-of-eight bandage. Early studies reported a non-union rate of 1% and negligible functional consequence with conservative management. However, the inclusion of pediatric fractures and an absence of modern functional assessments in these studies resulted in an underestimation of non-union rates and overly optimistic clinical outcomes. More recent data has demonstrated a non-union rate of 15% with approximately 30% of patients dissatisfied with their outcome following non-operative treatment. As a result, there has been renewed interest in surgical fixation of displaced midshaft clavicle fractures. In fact, the rate of operative fixation has exponentially increased following the publication of a landmark randomized controlled trial by the Canadian Orthopaedic Trauma Society (COTS) which was the first of many level I studies to demonstrate higher union rates, decreased rates of symptomatic malunion, earlier return to function, and improved patient-reported outcomes with plate fixation of displaced midshaft clavicle fractures.

Traditional plating techniques for open reduction and internal fixation of clavicle fractures involved the use of a single 3.5-mm plates placed superiorly or anteriorly. However, these plates are often very prominent under the skin causing irritation, and in many cases result in reoperation for hardware removal. The rate of reoperation for removal of symptomatic hardware has been reported to range from 8% to 66%. For this reason, there have been a number of different fixation strategies describes to minimize the need to return to the operating room for implant-related symptoms. These include intramedullary nailing and the use of anatomic precontoured clavicle plates positioned superiorly or anteroinferiorly. However, even with the use of precontoured plates, the reported hardware removal rate varies from 5% to 47%. This is likely due to the significant variation in clavicle anatomy (i.e., sigmoid curve, coronal bow and length) observed between individuals which precludes anatomic fitting of precontoured plates in all patients. In fact, Malhas and colleagues published a cadaveric study that found further contouring of precontoured plates was necessary in 73% of cases to optimize plate-bone fit.

More recently, a dual plate construct using two mini-fragment plates (i.e., 2.4-mm or 2.7-mm plates) placed orthogonally has been advocated as a means of decreasing the rate of reoperation for symptomatic hardware removal. In 2015, Prasarn et al. reported on a series of 17 patients undergoing clavicle fixation using a 2.7-mm plate positioned superiorly and a 2.4-mm plate positioned anteriorly and had no reoperations while noting a 100% union rate. The idea of dual plating is not new and is commonly used in the setting of clavicle fracture non-union fixation. Its efficacy has also been described in distal clavicle fractures. Dual plating may serve as the ideal low-profile implant option to help diminish the high rates of symptomatic implant removal observed with single plating. The benefits associated with a dual plate construct extend beyond a reduction in implant-related soft-tissue irritation. Intraoperatively, dual plating allows for more points of fixation, buttressing of anterior butterfly fragments, mini-fragment plates to be used as washers for multiple lag screws, and the use of either the superior or anterior plate as a reduction aid or clamp, while the second plate is applied. Based on existing biomechanical data in the literature, the ability of a dual plate construct to withstand multiplanar bending forces better than a single plate construct may also allow for early weight-bearing through the affected extremity. Despite the aforementioned benefits of dual plate fixation, there remains a lack of level I evidence for its use in the surgical management of acute midshaft clavicle fractures.