Title: Comparison of Radiologic and Arthroscopic Diagnosis of Distal Tibiofibular Syndesmosis Disruption in Acute Ankle Fracture
Authors: Tun Hing Lui M.B.B.S, F.R.C.S., F.H.K.A.M, Kai Yuen Ip M.B.Ch.B., M.R.C.S. and Hung Tsan Chow M.B.B.S, M.R.C.S.
Source: Arthroscopy: The Journal of Arthroscopic & Related Surgery 2005 Nov;21(11):1370.e1-e7
PODIATRIC RELEVANCE:
Acute ankle fractures are a common etiology seen throughout hospital emergency departments. When accessing type B and C (Dennis Weber Classification) fractures of the ankle, most clinicians assume a syndesmotic injury or diastasis has occurred. The diagnosis of syndesmotic injury depends on the clinical and radiographic evidence. The width of the tibiofibular “clear space” on both AP and mortise views appear to be the most reliable parameter for detecting subtle syndesmosis widening. However, with the advance of ankle arthroscopy, syndesmotic diastasis and instability in more than 1 plane can be detected more accurately.
METHODS:
A prospective study, including 53 Weber type B or C ankle fractures without radiographic evidence of frank syndesmosis diastasis from June 2002 to December 2003. The mean age of the patients was 35.4 years (range, 16 to 88 years). Standard AP and lateral radiographs of the injured ankles were taken after admission. Ice therapy was applied to the injured leg. Open reduction and internal fixation of the fractures with ankle arthroscopy was performed on all patients in the study. Surgical treatment consisted of open reduction and internal fixation of the distal fibular fracture by 3.5-mm AO Dynamic compression plate through standard lateral approach. Medial malleolar fractures were fixated with two 4-mm cannulated screws. After fracture fixation, the degree of syndesmotic instability was assessed using two methods. (1) Lateral force was applied to the distal fibula utilizing a bone hook and providing stress with AP radiography. A positive finding was lateral movement of the fibula or widening of the mortise on intraoperative radiographs. (2) Ankle arthroscopy allows direct visualization via anteromedial and anterolateral portals. The syndesmosis was then examined in all three planes and stresses were applied in all three planes. After analysis of the syndesmosis under arthroscopy, the disruption was then fixated with a 4.5-mm cortical screw purchasing all four cortices. The screws were then removed 12 weeks later and examined a second time under arthroscopy.
RESULTS:
Sixteen cases (30.2%) had positive intraoperative stress radiographs; 35 cases (66.0%) had positive arthroscopic findings of syndesmosis diastasis, including various combinations of coronal, sagittal, and rotational planes of instability. During second-look arthroscopy, 31 of 34 patients with syndesmotic screws showed healing of the syndesmotic ligaments and a stable syndesmosis.
COMMENTS:
In treating ankle fractures, intraoperative radiography exists as the main tool for detecting longitudinal instability and guiding the proper insertion of a syndesmotic screw. However, in terms of diagnosing a syndesmosis diastasis, ankle arthroscopy is the more sensitive method. With the advances of arthroscopy, surgeons are able to determine the different patterns of syndesmotic disruptions and properly reduce the deformity.
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Disclaimer:
Scientific Abstract Monthly postings are submitted by podiatric surgical residents. The ideas presented are not the opinions of the American College of Foot and Ankle Surgeons (ACFAS), nor are they presented as facts. ACFAS presents this information without any warranty of any kind, expressed or implied, and is not liable for its accuracy nor for any loss or damage caused by the user's reliance on information obtained in these areas.