AJR:182, January 2004 131 MRI Findings Associated with Distal Tibiofibular Syndesmosis Injury OBJECTIVE. Our objective was to describe the MRI findings associated with acute and chronic distal tibiofibular syndesmosis injury. MATERIALS AND METHODS. Ninety-four 1.5-T MRIs of ankles of 90 individuals with histories of severe sprain were assessed by two musculoskeletal radiologists for syndesmosis in- jury (acute, edema of the syndesmosis; chronic, disruption or thickening of the syndesmosis with- out edema). We examined associated MRI findings, including anterior talofibular ligament injury (scar, chronic injury; edema, acute injury), bone bruise, osteochondral lesion, tibiofibular joint congruity, tibiofibular recess height, and osteoarthritis. The Fisher’s exact test and analysis of variance test were used to evaluate the significance of the associations. RESULTS. In 94 ankles, syndesmosis injury was seen in 63% (n = 59; 23 acute; 36 chronic). Anterior talofibular ligament injury (acute or chronic) was seen on MRIs in 74% (n = 70; 49 with syndesmosis injury; 21 without; p = 0.03). Bone bruises were present in 24% (n = 23; 18/23 acute; 4/36 chronic; 4/35 no injury; p < 0.0001). Of these, talar dome osteochondral lesions were present in 28% (n = 26; 11/23 acute; 14/36 chronic; 1/35 no injury; p = 0.0001; 13 medial; 13 lateral). The tibiofibular joint was incongruent in 33% (n = 31; 6/23 acute; 21/36 chronic; 4/35 no injury; p < 0.0001). The tibiofibular recess (mean ± SD) was 1.2 ± 0.92 cm in acute cases, 1.4 ± 0.57 cm in chronic cases, and 0.54 ± 0.68 cm in cases with no syndesmosis injury (p < 0.0001). Osteoarthritis was present in 10% (n = 9; 1/23 acute; 7/36 chronic; 1/35 no injury; p = 0.06). CONCLUSION. Injury to the distal tibiofibular syndesmosis has a significant association with a number of secondary findings on MRI, including anterior talofibular ligament injury, bone bruises, osteochondral lesions, tibiofibular joint congruity, and height of the tibiofibular recess. nkle joint injuries are common and are usually related to lateral ligament sprain [1–6]. It is esti- mated that more severe injuries that include the distal tibiofibular syndesmosis make up between 1% and 20% of these ankle injuries [3, 5, 7, 8]. Although the exact mechanism is not certain, previous studies have hypothe- sized that syndesmosis injuries are due to a forced external rotation of the foot combined with internal rotation of the leg [8]. This type of injury is commonly seen in athletic activi- ties in which twisting injuries are prevalent, such as in football and skiing [8]. In patients with ankle sprains, those with syndesmosis injuries have a longer recovery time, often with poor rehabilitation outcomes and chronic ankle dysfunction [5, 8–11]. Al- though certain syndesmotic injuries may be diagnosed radiographically, these injuries are often missed because of the inability of ra- diographs to detect them [11]. Missed diag- nosis can lead to improper treatment, which can prolong recovery time. Prior studies have documented the ability of MRI to visualize the ligaments of the dis- tal tibiofibular syndesmosis [12, 13]; for the diagnosis of an anterior tibiofibular rupture, MRI has a sensitivity that ranges from 93% to 100%, with a specificity of 96–100% [12]. These figures showing high accuracy of MRI for diagnosis have been corroborated by oth- ers who report a 100% sensitivity and 93% specificity of MRI for injury to the anterior inferior syndesmotic ligament [14]. How- ever, MRI is not performed routinely for di- agnosis of ankle injuries; thus, sparse information pertains to MRI of syndesmosis injury. The purpose of this study was to char- acterize MRI findings associated with distal Kevin W. Brown 1 William B. Morrison 1 Mark E. Schweitzer 1,2 J. Antoni Parellada 1 Henry Nothnagel 1 Received January 6, 2003; accepted after revision July 30, 2003. 1 Department of Radiology, Thomas Jefferson University Hospital, 111 S 11th St., Ste. 3390, Gibbon Bldg., Philadelphia, PA 19107. Address correspondence to W. B. Morrison (William.Morrison@mail.tju.edu). 2 Present address: Department of Radiology, New York University Hospital for Joint Disease, 3012 17th St., New York, NY 10003. AJR 2004;182:131–136 0361–803X/04/1821–131 © American Roentgen Ray Society A Downloaded from www.ajronline.org by 52.73.204.196 on 05/18/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved