Diagnostic capability of dynamic ultrasound evaluation of supination-external rotation ankle injuries: a cadaveric study.

BACKGROUND: Ankle syndesmosis injuries are common and range in severity from subclinical to grossly unstable. Definitive diagnosis of these injuries can be made with plain film radiographs, but are often missed when severity or image quality is low. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide definitive diagnosis, but are costly and introduce the patient to radiation when CT is used. Ultrasonography may circumvent many of these disadvantages by being inexpensive, efficient, and able to detect injuries without radiation exposure. The purpose of this study was to evaluate the ability of ultrasonography to detect early stage supination-external rotation (SER) ankle syndesmosis injuries with a dynamic external rotational stress test. METHODS: Nine, all male, fresh frozen specimens were secured to an ankle rig and stress tested to 10 Nm of external rotational torque with ultrasonography at the tibiofibular clear space. The ankles were subjected to syndesmosis ligament sectioning and repeat stress measurements of the tibiofibular clear space at peak torque. Stress tests and measurements were repeated three times and averaged and analyzed using a repeated one-way analysis of variance (ANOVA). There were six ankle injury states examined including: Intact State, 75% of AITFL Cut, 100% of AITFL Cut, Fibula FX - Cut 8 cm proximal, 75% PITFL Cut, and 100% PITFL Cut. RESULTS: Dynamic external rotation stress evaluation using ultrasonography was able to detect a significant difference between the uninjured ankle with a tibiofibular clear space of 4.5 mm and the stage 1 complete injured ankle with a clear space of 6.0 mm (P < .02). Additionally, this method was able to detect significant differences between the uninjured ankle and the stage 2-4 injury states. CONCLUSION: Dynamic external rotational stress evaluation using ultrasonography was able to detect stage 1 Lauge-Hansen SER injuries with statistical significance and corroborates criteria for diagnosing a syndesmosis injury at ≥6.0 mm of tibiofibular clear space widening.

Relationship between fracture morphology of lateral malleolus and syndesmotic stability after supination-external rotation type ankle fractures.

BACKGROUND: Syndesmotic injury with supination-external rotation (SER)-type ankle fractures are well known for the serious damages to the osseous and soft tissue envelope. However, the Lauge-Hansen classification system does not provide sufficient information related to syndesmotic injury. In this study, we aimed to investigate factors for preoperative detection of syndesmotic injury according to fracture patterns in SER III and IV ankle fractures by using radiography and computed tomography (CT). METHODS: All operative SER III and IV ankle fractures treated by a single surgeon from 2009 to 2015 were enrolled in a retrospective database. Based on computed tomographic evidence and intra-operative Cotton test, stable and unstable groups of the ankle factures were divided. RESULTS: A total of 52 patients with SER III, 75 patients with SER IV, and 27 patients with SER IV equivalent ankle fractures were identified, with 106 in the unstable syndesmosis group (68.8%) and 48 patients in the stable syndesmosis group (31.2%). Medial space widening and fragment angle of the fibular posterior cortex were significant predictors. The cutoff values of these factors were 4.4 mm and 32.8 degrees, respectively. CONCLUSIONS: CT was superior to simple radiography in predicting syndesmotic injury at the preoperative period in SER-type III and IV. Medial space widening and fragment angle of the fibular posterior cortex, as predictive factors, showed significant correlations. In particular, sharper fragment angle of the posterior cortex indicated higher probability of instability that remained after fracture fixation.

Morphological characteristics of the posterior malleolar fragment according to ankle fracture patterns: a computed tomography-based study.

BACKGROUND: The posterior malleolar fragment (PMF) of an ankle fracture can have various shapes depending on the injury mechanism. The purpose of this study was to evaluate the morphological characteristics of the PMF according to the ankle fracture pattern described in the Lauge-Hansen classification by using computed tomography (CT) images. METHODS: We retrospectively analyzed CT data of 107 patients (107 ankles) who underwent surgery for trimalleolar fracture from January 2012 to December 2014. The patients were divided into two groups: 76 ankles in the supination-external rotation (SER) stage IV group and 31 ankles in the pronation-external rotation (PER) stage IV group. The PMF type of the two groups was assessed using the Haraguchi and Jan Bartonicek classification. The cross angle (α), fragment length ratio (FLR), fragment area ratio (FAR), sagittal angle (θ), and fragment height (FH) were measured to assess the morphological characteristics of the PMF. RESULTS: The PMF in the SER group mainly had a posterolateral shape, whereas that in the PER group mainly had a posteromedial two-part shape or a large posterolateral triangular shape (P = 0.02). The average cross angle was not significantly different between the two groups (SER group = 19.4°, PER group = 17.6°). The mean FLR and FH were significantly larger in the PER group than in the SER group (P = 0.024, P = 0.006). The mean fragment sagittal angle in the PER group was significantly smaller than that in the SER group (P = 0.017). CONCLUSIONS: With regard to the articular involvement, volume, and vertical nature, the SER-type fracture tends to have a smaller fragment due to the rotational force, whereas the PER-type fracture tends to have a larger fragment due to the combination of rotational and axial forces.

Effect of syndesmosis injury in SER IV (Weber B)-type ankle fractures on function and incidence of osteoarthritis.

BACKGROUND: Syndesmosis fixation of Lauge-Hansen SER IV, Weber B ankle fractures is controversial. This study compared a matched pair of SER IV patients with stress proven syndesmotic injuries with the same number without stress proven syndesmotic injury in terms of functional, pain, and radiologic result. METHODS: The study was based on a RCT-study comparing syndesmotic transfixation to no fixation in SER IV (Weber B)-type ankle fractures. Twenty-four patients with a syndesmosis injury found on the intraoperative 7.5 Nm standardized external rotation test were compared to 24 patients with a stable syndesmosis. The pairs were matched by fracture morphology, sex, and age. The primary outcome measure was ankle function as assessed by the Olerud-Molander score. Weight-bearing plain radiographs and 3T MRI of the injured ankle were used to assess ankle joint congruity and osteoarthritis, according to Kellgren-Lawrence classification and cartilage defects. RESULTS: The Olerud-Molander score was 86 in syndesmosis injury patients and 90 in patients with normal syndesmosis (P = .28). The incidence of ankle joint osteoarthritis on plain radiographs was not significantly different between the groups (Grade I 5% vs 21%; Grade II 86% vs 75%; Grade III 9% vs 4%; P = .34). MRI scans showed TC joint cartilage defects in 54% of the patients: 12 (56%) in the syndesmosis injury group vs 13 (54%) in the group without syndesmosis injury (P > .9). CONCLUSION: After 4 to 6 years of follow-up, clinical and radiologic outcome were not different in patients with syndesmosis injury compared to patients with stable syndesmosis in SER IV (Weber B)-type ankle fractures. LEVEL OF EVIDENCE: Prognostic Level II, comparative study.

The treatment of unstable ankle fractures in patients over eighty years of age.

BACKGROUND: The current study examined the outcomes of operative treatment of unstable ankle fractures in patients at least 80 years old at the time of injury. METHODS: Of 2,682 patients who presented for treatment of ankle fractures, 17 patients met the study criteria. These patients had open reduction and internal fixation after sustaining 15 closed and two open unstable ankle fractures. There were 11 type B fractures and six type C fractures by the Danis-Weber classification, and 12 supination-external rotation and five pronation-external rotation fractures by the Laugen-Hansen classification systems. RESULTS: When noncompliant patients who developed complications were removed from analysis, the fixation failure and deep infection rates were 0% each. CONCLUSIONS: These results highlight the importance of patient compliance and non-weightbearing status in the treatment of ankle fractures in patients over 80 years.