Posterior Malleolus Fixation Using a Suture Button

Abstract

Category: Trauma Introduction/Purpose: Despite the increasing awareness and literature addressing fractures of the posterior malleolus (PM), no biomechanical nor clinical studies have been able to establish consensus surgical indications or treatment methods for these common orthopedic injuries. A posterolateral or posteromedial approach allows fixation to be placed in a compressive mode as opposed to the more traditional anterior to poster placed screws which relies upon static screw placement. We designed a technique that utilizes a suture button device for fixation. This technique allows for compression across the fracture site while avoiding cumbersome patient positioning and extensive posterior dissection. Methods: Our technique utilizes a standard lateral approach to the fibula which is fixed routinely. Finger dissection is then carried out between the posterior fibula and perennial tendons to grant access to the PM which typically reduces via ligamentotaxis. A PCL drill guide is then placed on the substance of the PM and a cannulated drill is advanced through the distal tibia from anterior to posterior after careful dissection through a small incision on the anterior tibia. A suture lasso then brings the suture button through the drill tunnel and it is compressed over a knotless endobutton which rests on the anterior tibia. The medial malleolus is then addressed routinely. Following placement of all hardware an external rotation stress test is performed to assess syndesmotic stability. After IRB approval the clinical and radiographic data of patients who underwent this technique was retrospectively reviewed. Results: Seven patients underwent treatment of a PM fracture using our technique. All cases achieved an anatomic reduction of the PM based on available imaging. One patient was found to have a loss of reduction of her medial malleolus at the first post- operative visit and underwent revision surgery with a good result. Final follow up averaged 9.5 months. Four of the seven patients underwent additional surgical procedures. Final ROM was available for 5 patients. Of the five, 4 achieved dorsiflexion greater than 5 degrees and had an arc of motion greater than 35 degrees. The final patient had a final ROM arc of 10-30 degrees of plantar flexion despite progressive dorsiflexion casting and lysis of adhesions. AOFAS score of available patients averaged 81.5. Conclusion: Our technique of using a suture button as fixation for PM fractures has several advantages. First, patient position improves surgical ease. Second, this approach avoids extensive posterior dissection and bulky hardware which we believe may lead to posterior scar formation and resultant ankle stiffness. Finally, the posterior button allows for compression of the PM which may contribute to the improved results seen with a posterior approach. We were able to achieve a radiographically anatomic reduction, satisfactory ROM and good outcome scores. We believe that our technique is a viable option in those injuries that benefit from surgical treatment of the PM component.