Original Research
Effect of Simulated Lateral Process Talus "Fracture Excision" on Its Ligamentous Attachments
Am J Orthop. 2009 May;38(5):222-226
Author and Disclosure Information
Phillip Langer, MD, Florian Nickisch, MD, David Spenciner, PE, ScM, and Christopher DiGiovanni, MD
Dr. Langer is Assistant Team Physician and Orthopedic Surgeon of the NFL Atlanta Falcons and the NHL Atlanta Thrashers, Atlanta Sports Medicine & Orthopedic Center, Atlanta, Georgia.
Dr. Nickisch is Assistant Professor of Orthopaedic Surgery, University of Utah Orthopaedic Center, Salt Lake City, Utah.
Mr. Spenciner is Test Facility Manager, CORO Laboratory, Department of Orthopedics, and Dr. DiGiovanni is Associate Professor and Chief, Division of Foot and Ankle, Department of Orthopedics, Brown Medical School/Rhode Island Hospital, Providence, Rhode Island.
Recent epidemiologic studies highlight lateral talar process fractures as snowboarder’s fracture or snowboarder’s ankle. Snowboarding is the fastest growing sport worldwide, so lateral talar process fractures are increasing in frequency and mandating a more careful assessment of injury patterns, surrounding tissue involvement, and treatment strategy.
In this study, we evaluated the effects of lateral talar process fracture on the footprints of 3 lateral stabilizing ligaments of the ankle and subtalar joint—the lateral talocalcaneal ligament (LTCL), the anterior talofibular ligament (ATFL), and the posterior talofibular ligament (PTFL).
The musculotendinous structures from 10 fresh cadaveric limbs were removed and the distal fibula reflected to provide visualization of the lateral talar process and ligamentous attachments. Length and width of the LTCL, ATFL, and PTFL footprints on the lateral process of the talus were measured with calipers before and after removal of a 1-cm3 simulated fracture fragment. Relative changes in the attachment site areas for the 3 ligaments were determined.
Mean pre-excision footprint areas were 80.57 mm2 (LTCL), 224.38 mm2 (ATFL), and 394.18 mm2 (PTFL); mean postexcision footprint areas were 2.10 mm2 (LTCL), 194.89 mm2 (ATFL), and 335.18 mm2 (PTFL); and mean decreases calculated as percentages of the original areas were 97.5% ± 3.5% (LTCL), 11.7% ± 13.0% (ATFL), and 14.3% ± 12.3% (PTFL).
Removal of a 1-cm3 bony fragment from the lateral talar process involves 3 of the major lateral stabilizing ligaments: approximately 100% of LTCL and approximately 10% to 15% of ATFL and PTFL.