Abstract
Introduction: Ankle inversion injuries are common, with an incidence of 1 per day per 10,000 of the population. Chronic instability is a frequent sequela, and has been estimated to occur after approximately 10 to 20% patients, regardless of the type of initial treatment. Magnetic Resonance Imaging (MRI) has become a routine diagnostic tool in investigating knee injuries, but little has been published concerning ankle injuries and ankle instability.
Aim: To compare the efficacy of conventional magnetic resonance (MR) imaging and stress radiography in the detection of lateral collateral ligament abnormalities in patients with chronic ankle instability.
Materials and Methods: All patients presenting to the senior author’s OPD with clinical impression of ankle instability were investigated prospectively using MRI and stress x-rays (Telos). These films were officially reported and then, these reports were subsequently reviewed post-anatomical reconstruction.
Results: Over a two-year period, 18 patients underwent anatomical reconstruction using the modified Brostrom technique. MRI identified a tear of the anterior talofibular (AFT) ligament in 12 (66%) patients, and the calcaneofibular (CF) ligament was torn in 9 (50%) patients. Stress radiography identified instability of 14 of the 18 (77%) patients. Stress radiography identified instability of 14 of the 18 (77%) patients. Surgical exploration revealed either attenuation or rupture of either the AFT and/or CF ligaments in all 18 patients. MRI demonstrated concomitant injuries to the ankle and subtalar joints, including peroneal tenosynovitis (76%), anterolateral impingement syndrome (66%) and attenuated peroneal retinaculum (55%).
Conclusion: Ankle instability may be more reliably demonstrated using stress x-rays than MRI: however, lowfield MRI is a very useful diagnostic tool in the study of concomitant ankle injuries and we would suggest that both modalities be considered, especially if surgical intervention is anticipated.
The abstracts were prepared by Raymond Moran. Correspondence should be addressed to him at the Irish Orthopaedic Assocation, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11, Ireland.
