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.

Correlation of weightbearing radiographs and stability of stress positive ankle fractures.

BACKGROUND: A positive external rotation stress test has been used as an indication for operative treatment of fractures of the lateral malleolus. The objective of the current study was to ascertain the results of a protocol initially treating stress positive ankle fractures nonoperatively and utilizing weightbearing radiographs in surgical decision making. METHODS: We performed a prospective study of lateral malleolar fractures with an associated medial ligamentous injury. All patients with fractures of the lateral malleolus with medial sided symptoms and/or signs, and an intact ankle mortise underwent an external rotation stress test to confirm injury to the deltoid ligament (stress positive). Patients with a positive stress test were placed in a short-leg walking cast and seen in 7 days where weightbearing radiographs of the ankle were obtained. If the radiographs demonstrated an intact mortise, then nonoperative treatment was continued. If the weightbearing radiographs demonstrated medial clear space widening, then the patient was offered operative treatment to restore the congruency of the ankle mortise. Patients were assessed for conversion to operative treatment, complications, and functional outcome. Thirty-eight patients were enrolled in the study. Using Lauge-Hansen classification 36 (95%) were stress positive supination-external rotation fractures and 2 (5%) were stress positive pronation-external rotation fractures. Followup assessment was performed at a minimum of 6 months and averaged 12 months. RESULTS: Weightbearing radiographs at the first post-injury clinic visit had an average medial clear space of 2.9 ±0.9 mm. Three (8%) patients met our criteria for medial clear space widening and underwent operative treatment. Of these three patients, two were pronation-external rotation fracture patterns. Therefore, 3% of the supination-external rotation IV fractures, and all of the pronation-external III/IV rotation fractures ultimately required operative treatment. At final followup, the average AOFAS hindfoot score was 92 ±8.1. CONCLUSION: Ligamentous supination-external rotation Stage IV fractures with an intact mortise on static radiographs can be initially treated nonoperatively. Weightbearing radiographs should be utilized to assess congruency of the ankle mortise during an early post-injury visit. Utilizing this approach, a significant number of surgeries were avoided, and good to excellent results were obtained. From our early experience, nonoperative treatment of pronation-external rotation III/IV injuries using this protocol is not recommended.

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.