Tibiofibular syndesmosis in acute ankle fractures: additional value of an oblique MR image plane.

OBJECTIVE: To evaluate the additional value of a 45° oblique MRI scan plane for assessing the anterior and posterior distal tibiofibular syndesmotic ligaments in patients with an acute ankle fracture. MATERIALS AND METHODS: Prospectively, data were collected for 44 consecutive patients with an acute ankle fracture who underwent a radiograph (AP, lateral, and mortise view) as well as an MRI in both the standard three orthogonal planes and in an additional 45° oblique plane. The fractures on the radiographs were classified according to Lauge-Hansen (LH). The anterior (ATIFL) and posterior (PTIFL) distal tibiofibular ligaments, as well as the presence of a bony avulsion in both the axial and oblique planes was evaluated on MRI. MRI findings regarding syndesmotic injury in the axial and oblique planes were compared to syndesmotic injury predicted by LH. Kappa and the agreement score were calculated to determine the interobserver agreement. The Wilcoxon signed rank test and McNemar's test were used to compare the two scan planes. RESULTS: The interobserver agreement (κ) and agreement score [AS (%)] regarding injury of the ATIFL and PTIFL and the presence of a fibular or tibial avulsion fracture were good to excellent in both the axial and oblique image planes (κ 0.61-0.92, AS 84-95%). For both ligaments the oblique image plane indicated significantly less injury than the axial plane (p < 0.001). There was no significant difference in detection of an avulsion fracture in the axial or oblique plane, neither anteriorly (p = 0.50) nor posteriorly (p = 1.00). With syndesmotic injury as predicted by LH as comparison, the specificity in the oblique MR plane increased for both anterior (to 86% from 7%) and posterior (to 86% from 48%) syndesmotic injury when compared to the axial plane. CONCLUSION: Our results show the additional value of an 45° oblique MR image plane for detection of injury of the anterior and posterior distal tibiofibular syndesmoses in acute ankle fractures. Findings of syndesmotic injury in the oblique MRI plane were closer to the diagnosis as assumed by the Lauge-Hansen classification than in the axial plane. With more accurate information, the surgeon can better decide when to stabilize syndesmotic injury in acute ankle fractures.

[Surgical techniques of open reduction and internal fixation for ankle fracture].

OBJECTIVE: To evaluate the surgical techniques of open reduction and internal fixation performed for ankle fracture retrospectively and the corresponding clinical outcomes. METHODS: From March 2001 to January 2006, 242 patients with ankle fracture were treated. A total of 85 patients with complete clinical data were analyzed. According to the Lauge-Hansen classification system, the fractures were classified into pronation-external rotation (grade II) in 12 cases and grade IV in 9 cases, supination-external rotation (grade II) in 34 cases and grade IV in 16 cases, supination-adduction (grade II) in 8 cases, and pronation-abduction in 6 cases. The reduction and internal fixation started with lateral malleolus, then medial malleolus and posterior malleolus, and distal tibiofibular syndesmosis in sequence. Among 10 cases, 5 of the distal tibiofibular syndesmosis were fixed with one screw through 3 layers of bone cortexes. All cases were auxiliarily fixed with plaster pad for 4 to 6 weeks after operation. RESULTS: The follow-up period varied from 6 to 36 months, with an average of 10 months. There were no local complications such as malunion or nonunion of the fractures and deformity of the ankle. The inserted screw to distal tibiofibular syndesmosis was not broken. The patients were evaluated with Baird-Jackson scoring system. The numbers of the patients who had excellent, good, fair and poor results were 53, 23, 6, 3, respectively. The excellent and good rate was 89.4%. CONCLUSION: Operative treatment may provide satisfactory clinnical outcomes for ankle fracture. Proper internal fixation and correct fracture pattern estimation are of importance to achieve and gain better long-term results.

Ankle fractures. The Lauge-Hansen classification revisited.

Rational treatment of ankle fractures requires knowledge of the extent of bone and soft tissue injury. Although the Lauge-Hansen classification attempts to do this by relating specific fracture patterns to injury mechanism, the experimental underpinning for this classification has not been reexamined rigorously using modern experimental methods. This study examines the hypothesis that the clinically occurring supination and external rotation injury pattern does not result from the mechanism described by Lauge-Hansen. Thirty-two anatomic specimen ankles were mounted on an MTS machine for combined axial loading with external rotation to failure testing. A foot plate supinated the foot 25 degrees. Testing was performed with the ankle at neutral, 25 degrees plantar flexed, 10 degrees to 15 degrees dorsiflexed, and in 6 degrees to 8 degrees leg valgus. Pure supination and external rotation with the ankle in neutral did not result in the Lauge-Hansen supination and external rotation type fractures. This outcome was not altered if the ankle specimens initially were placed in plantar flexion or dorsiflexion. The addition of a valgus load, which pushes the talus laterally against the fibula, resulted in the classic Lauge-Hansen supination and external rotation type fracture. All specimens had an isolated lateral injury or a lateral injury that preceded medial injury.