Sat., 10/6/12 Tibial Fractures, PAPER #119, 4:38 pm OTA-2012
Predictive Radiographic Markers for Concomitant Ipsilateral Ankle Injuries in Tibial Shaft Fractures
Patrick Schottel, MD; Marschall B. Berkes, MD; Milton Thomas Michael Little, MD;
Lionel Enrique Lazaro, MD; David L. Helfet, MD; Dean G. Lorich, MD;
Hospital for Special Surgery, New York, New York, USA
Purpose: Recent publications have identified a tibial shaft fracture variant that contains an ipsilateral posterior malleolus fracture (PMF). As PMFs typically represent only one component of a rotational ankle injury, we hypothesized that tibia fractures with a concomitant rotational ankle injury are underappreciated. We also hypothesized that characteristic tibia and fibula fracture patterns are predictive of a rotational ankle injury. The purpose of this study was to quantify the incidence as well as identify the fracture patterns that are predictive of a concomitant ipsilateral ankle injury.
Methods: Preoperative full-length tibia and ankle radiographs as well as a CT scan of the tibia that included the ankle were obtained on all operative tibial shaft fractures from 2009 to 2011. 71 patients were retrospectively reviewed with the location, pattern, and AO classification recorded. Radiographic and CT imaging was then scrutinized for evidence of an ipsilateral rotational ankle injury as judged by the presence of a PMF, an anterior inferior tibiofibular ligament (AITFL) avulsion fracture, or a medial malleolus fracture. The Fisher exact test was used to determine significant associations between fracture patterns and the presence of a rotational ankle injury.
Results: 35 (49.3%) of the 71 tibial shaft fracture patients were found to have a concomitant ipsilateral ankle injury. Of those, isolated PMFs occurred in 48.6% (17 of 35), isolated AITFL avulsion fractures occurred in 8.6% (3 of 35) and the remainder of patients possessed two or more ankle injury markers (PMFs, medial malleolus fractures, AITFL avulsion fractures, and a deltoid ligament tear). 31 of 35 (88.6%) concomitant ankle injuries occurred in patients with a spiral pattern type tibia fracture of the distal third diaphysis or metadiaphysis (P <0.001). Identification of a distal third spiral tibia fracture on initial radiographs resulted in an odds ratio (OR) of 13.71 (95% confidence interval [CI], 3.50-58.76) for the presence of an ankle injury compared with all other nonspiral patterns (transverse, oblique, segmental, and butterfly). Distal third spiral tibia fractures had a diagnostic sensitivity of 88.6%, specificity of 63.9%, and positive and negative predictive values of 70.5% and 85.2%, respectively, for the presence of an ankle injury. Also, patients with either a transverse pattern or absent fibula fracture were significantly less likely to have an associated ankle injury (OR 0.04; 95% CI, 0.002-0.731; P = 0.016).
Conclusions: Ipsilateral ankle injuries including PMFs, AITFL avulsion fractures, and medial malleolar fractures are commonly associated with tibial shaft fractures, specifically distal third spiral type. Recognition of these associated ankle injuries is important as it may impact intraoperative and postoperative management. Further studies examining the outcomes of patients with or without ipsilateral ankle injury is warranted to determine the clinical significance of this entity.Alphabetical Disclosure Listing (808K PDF)
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