MRI findings associated with distal. Tibiofibular Syndesmosis Injury

Transcription

1 Kevin W. Brown 1 William B. Morrison 1 Mark E. Schweitzer 1,2 J. ntoni Parellada 1 Henry Nothnagel 1 Received January 6, 2003; accepted after revision July 30, Department of Radiology, Thomas Jefferson University Hospital, 111 S 11th St., Ste. 3390, Gibbon Bldg., Philadelphia, P ddress correspondence to W. B. Morrison (William.Morrison@mail.tju.edu). 2 Present address: Department of Radiology, New York University Hospital for Joint Disease, th St., New York, NY JR 2004;182: X/04/ merican Roentgen Ray Society MRI Findings ssociated with Distal Tibiofibular Syndesmosis Injury OBJECTIVE. Our objective was to describe the MRI findings associated with acute and chronic distal tibiofibular syndesmosis injury. MTERILS ND 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 injury (acute, edema of the syndesmosis; chronic, disruption or thickening of the syndesmosis without 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). nterior 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 < ). Of these, talar dome osteochondral lesions were present in 28% (n = 26; 11/23 acute; 14/36 chronic; 1/35 no injury; p = ; 13 medial; 13 lateral). The tibiofibular joint was incongruent in 33% (n = 31; 6/23 acute; 21/36 chronic; 4/35 no injury; p < ). 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 < ). 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 estimated that more severe injuries that include the distal tibiofibular syndesmosis make up between 1% and 20% of these ankle injuries [3, 5, 7, 8]. lthough the exact mechanism is not certain, previous studies have hypothesized 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 activities 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]. lthough certain syndesmotic injuries may be diagnosed radiographically, these injuries are often missed because of the inability of radiographs to detect them [11]. Missed diagnosis can lead to improper treatment, which can prolong recovery time. Prior studies have documented the ability of MRI to visualize the ligaments of the distal 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 % [12]. These figures showing high accuracy of MRI for diagnosis have been corroborated by others who report a 100% sensitivity and 93% specificity of MRI for injury to the anterior inferior syndesmotic ligament [14]. However, MRI is not performed routinely for diagnosis of ankle injuries; thus, sparse information pertains to MRI of syndesmosis injury. The purpose of this study was to characterize MRI findings associated with distal JR:182, January

2 Brown et al. tibiofibular syndesmosis injuries, both acute and chronic. Materials and Methods Ninety-four MRIs of the ankle in 90 patients (51 male, 39 female; age range, years; mean, 37 years) were selected after we searched for past MRI studies with the words ankle sprain in the dictation. fter these studies were separated, they were examined for the presence of syndesmosis injury in addition to the associated findings (e.g., bone bruise). Studies were collected from a database over 2 years. MRI was performed using a 1.5-T scanner (Signa, General Electric Medical Systems, Milwaukee, WI) with an extremity coil around the ankle; the foot was positioned at 90 in relation to the leg. The MRI protocol consisted of coronal and axial T2-weighted fast spin-echo images with fat suppression, axial proton density weighted fast spin-echo images, sagittal fast spin-echo inversion recovery images, and sagittal T1-weighted spinecho images. T2-weighted fast spin-echo images were acquired with a TR range/te eff range of 3,000 7,500/60 90; echo-train length of 8; slice thickness of 4 mm; skip of 1 mm; 2 3 signal averages; field of view of cm; and matrix of T1-weighted spin-echo images were acquired with a TR range/te range of /10 20; slice thickness of 4 mm; skip of 1 mm; 2 signal averages; field of view of cm; and matrix of xial proton density weighted fast spin-echo images were obtained with a TR range/ TE eff range of 2,500 4,000/30-40; echo-train length of 4; slice thickness of 4 mm; skip of 1 mm; 2 signal averages; field of view of cm; and matrix of Sagittal fast spin-echo inversion recovery images were obtained with 2,000 5,000/20 40; inversion time of 150 msec, echo-train length of 8; slice thickness of 4 mm; skip of 1 mm; 2 signal averages; field of view of cm; and matrix of Frequency-selective fat saturation was used to acquire fat-suppressed sequences. Two musculoskeletal radiologists, by consensus, retrospectively examined the MRIs. Syndesmosis injury (injury to the anterior tibiofibular ligament) was defined as acute (edema around or in the ligament) (Fig. 1) or chronic (disruption or thickening of the ligament without edema) (Fig. 2). lthough there are numerous anatomic components of the distal tibiofibular syndesmosis, we evaluated the anterior tibiofibular ligament as a marker of injury to the complex as a whole because in our experience, compared with the other components, this portion is most commonly injured and is most reliably and consistently visualized on MRI. nterior talofibular ligament injury was defined as acute (edema around or in the ligament) or chronic (disruption or thickening of the ligament without edema). Several associated MRI findings Fig. 1. cute distal tibiofibular syndesmosis injury in 29-year-old man., xial proton density weighted fast spin-echo image (TR/TE eff, 3,250/37) of right ankle shows disruption (arrow) of anterior syndesmotic ligament. B, xial fat-suppressed T2-weighted fast spin-echo image (4,783/60) of right ankle shows edema (arrow) in and around ligament. This criterion was used to identify ankles with acute syndesmosis injury. B were examined. Bone bruises had ill-defined increased marrow signal intensity on T2-weighted images (Fig. 3). The location of bone bruises and fractures was also recorded. Fractures were defined as a linear signal with surrounding bone marrow edema on T2-weighted images. We recorded the presence of an osteochondral lesion, defined as a solitary subchondral focus of signal on T2- weighted images in the talar dome without similar findings in the tibia (Fig. 4). The location of the osteochondral lesion (lateral or medial talar dome) was noted. In addition, on sagittal images, a line was drawn between articular surfaces of the ankle and divided into three equal zones representing anterior, middle anterior, and posterior thirds. Each osteochondral lesion was also categorized into one of these three locations. Distal tibiofibular joint congruity was examined on axial proton density weighted images at the level of the distal tibiofibular joint (Fig. 5). congruent joint consisted of a smooth articular surface and joint margins with no subluxation, diastasis, or enthesopathic proliferation. n incongruent joint was defined as a joint with an irregular surface, sharpened margins, articular offset of diastasis, or proliferation at the interosseous membrane (Fig. 6). The tibiofibular joint recess height was measured in centimeters on coronal T2-weighted images from the lateral talar dome to the maximal superior extent of joint fluid between the tibia and fibula (Fig. 7). Osteoarthritis was defined as marginal osteophytes or subchondral cysts (multiple or on both sides of the joint to distinguish osteoarthritis from solitary osteochondral lesions) on any sequence. On the basis of these data, three subpopulations were defined, consisting of patients with MRI evidence of acute syndesmosis injury, chronic syndesmosis injury, and normal syndesmosis. The number of times that an associated finding occurred for each of these groups was recorded, and the totals were compared between the three categories. The Fisher s exact test and analysis of variance test were used to evaluate for significance of the associations. p value of less than 0.05 was considered to be statistically significant. Investigational review board approval was obtained for this retrospective study. Results In the 94 ankles, MRI evidence of syndesmosis injury was present in 59 (63%). Criteria for acute syndesmosis injury were present in 23 (24%). Chronic syndesmosis injuries made up 36 (38%) of the 94 ankles studied. Thirty-five (37%) had no MRI evidence of syndesmosis injury (Table 1). In terms of associated findings, anterior talofibular ligament injury was seen on MRI in 70 (74%) (49 with syndesmosis injury; 21 without; p = 0.03). Bone bruises or fractures were present in 26 (28%) of the 94 ankles. 132 JR:182, January 2004

3 MRI of Tibiofibular Syndesmosis Injury Eighteen (78%) of the 23 ankles with acute syndesmosis injury had bone bruises as compared with four (11%) of the 35 ankles with no syndesmosis injury. Bone bruises were significantly associated with acute syndesmosis injury (p < ). Of the 22 ankles with both bone bruises and syndesmosis injuries (acute or chronic), 13 bone bruises occurred in the talus with nine in the medial talus (six in the medial talar dome and three in the anterior medial talus) and six bone bruises were located in the tibia (three in the posterior malleolus, one in the anterior tibia, and two in the medial malleolus). There were three fractures in the posterior malleolus. Talar dome osteochondral lesions were present in 26 ankles (28%) studied (Table 1). Eleven (48%) of the 23 ankles with acute syndesmosis injury and 14 (39%) of the 36 ankles with chronic syndesmosis injury had osteochondral lesions. Only one (3%) of the 35 ankles with no syndesmosis injury had an osteochondral lesion. Osteochondral lesions were significantly associated with both acute and chronic syndesmosis injury (p = and p = , respectively). Location of osteochondral lesions was equally distributed between the medial (n = 13) and lateral (n = 13) talar dome. Of the 13 medial talar dome osteochondral lesions, 12 (92%) were located in the middle third of the articular surface. One (8%) was located in the posterior third. Laterally, six (46%) of the 13 osteochondral lesions were located in the middle third. Two (15%) were in the anterior third, and five (38%) were in the posterior third. The tibiofibular joint was incongruent in 31(33%) of the 94 ankles studied. Twenty-one (58%) of the 36 ankles with chronic syndesmosis injury had tibiofibular joint incongruity compared with only four (11%) of the 35 ankles with no syndesmosis injury and six (26%) of 23 ankles with acute injury (Table 1). Tibiofibular joint incongruity was significantly associated with chronic syndesmosis injury (p < ). The tibiofibular recess height was significantly greater in both acute syndesmosis injuries (1.2 ± 0.92 cm) and chronic syndesmosis injuries (1.4 ± 0.57 cm) compared with the ankles with no syndesmosis injury (0.54 ± 0.68 cm) (p < ). Osteoarthritis was present in nine (10%) of the 94 ankles. One case of osteoarthritis occurred in the group with acute syndesmosis injury. Seven cases of osteoarthritis occurred in the group with chronic syndesmosis injuries, and one case occurred in the JR:182, January 2004 group with no syndesmosis injury. Osteoarthritis was not significantly associated with acute or chronic syndesmosis injury (p = 0.06) (Table 1). In our 94 ankle MRIs of patients with a provided clinical history of severe sprain, we found that 63% had distal syndesmosis inju- B Discussion Fig. 2. Chronic distal tibiofibular syndesmosis injury in 46-year-old man. Note osteochondral lesion (arrowhead) at medial talar dome on both and B., xial proton density weighted fast spin-echo image (TR/TEeff, 3,500/38) of right ankle shows thickened anterior syndesmotic ligament (arrow). B, xial T2-weighted image (4,800/60) of right ankle shows no edema around ligament (arrow). This criterion was used to identify ankles with chronic syndesmosis injury. B Fig. 3. Bone bruise in 16-year-old boy with acute syndesmosis injury. rrowheads indicate medial talus, and arrows indicate edematous lateral ligaments., xial T2-weighted fat-suppressed fast spin-echo image (TR/TEeff, 5,433/67) of left ankle shows marrow edema (arrowheads) in medial talus. B, Coronal fat-suppressed T2-weighted fast spin-echo image (3,167/76) shows that bone bruise is consistent with inversion mechanism of injury. Edematous lateral ligaments indicate acute injury. Bone bruises were found to have significant association with acute syndesmosis injuries. 133

4 Brown et al. ries. Distal syndesmosis injury was found to have a statistically significant association with anterior talofibular ligament injury, bone bruise and fracture, osteochondral lesion, tibiofibular joint incongruity, and an increased height of the tibiofibular recess. Syndesmosis injury was not found to be significantly associated with osteoarthritis in our population. Fig. 4. Osteochondral lesion in 46-year-old man. Coronal fat-suppressed T2-weighted fast spin-echo image (TR/TEeff, 5,783/68) of right ankle shows solitary hyperintense subchondral focus (arrow) at talar dome. Osteochondral lesions were found to be significantly associated with acute and chronic syndesmosis injuries. Fig. 5. Tibiofibular joint congruity in 26-year-old woman without syndesmosis injury. xial proton density weighted fast spin-echo image (TR/TEeff, 4,000/ 30) of left ankle shows normal, smooth distal tibiofibular joint (arrows). Fig. 6. Tibiofibular incongruity in 43-year-old man with chronic syndesmosis injury. xial proton density weighted fast spin-echo image (TR/TEeff, 3,450/36) of right ankle shows irregular tibiofibular joint (arrows). Incongruity of distal tibiofibular joint was found to be significantly associated with chronic syndesmosis injury. Fig. 7. Prominent tibiofibular recess height in ankle of 26-year-old woman with chronic syndesmosis injury. Coronal fat-suppressed T2-weighted image (TR/ TEeff, 7,350/68) of left ankle shows method for measuring tibiofibular height (arrow). Recess was measured from talar dome to superior extent of recess (solid lines). In this case, recess height measured 1.6 cm. 134 Several of these findings are to be expected with severe ankle injury. For instance, an injury severe enough to disrupt the distal syndesmosis would also probably injure the anterior talofibular ligament. Bone bruise is an expected finding in an acute, severe injury that would also cause a syndesmosis injury. In the ankles with syndesmosis injuries, nine (47%) of the 19 bone bruises were in a medial location, suggesting an inversion mechanism as a major one associated with syndesmosis injury. nother expected finding was the presence of osteochondral lesions, which were significantly more common in ankles with syndesmosis injury than in those without. Osteochondral lesions are a recognized complication of ankle sprain and fracture [15, 16]. The finding of an osteochondral lesion is one potential source of chronic pain in patients with prior ankle sprain. Osteochondral lesions were located in an equal distribution at the medial and lateral talar dome, which is similar to the findings of Canale and Belding [17]. Osteochondral lesions in our population were most common at the middle third of the talar dome, measured from the anterior to posterior articular surface. Eighteen (69%) of the 26 osteochondral lesions were at the middle third; however, others have shown that the most common location of osteochondral lesions is the anterolateral and posteromedial talar dome [15, 18, 19]. This difference in distribution may reflect a selection bias in our population, which included only patients with ankle sprain. Radiographically, ossification at the distal tibiofibular joint or interosseous membrane has been described with chronic syndesmosis injury [20]. This corresponds to our finding of irregularity of the joint in patients with evidence of chronic syndesmosis injury. The same process that results in the radiographic appearance of heterotopic ossification (injury of the interosseous membrane) may cause an irregular appearance of adjacent cortical margins on MRI and result in the appearance of the distal tibiofibular joint incongruity that we observed. In addition to joint incongruity, the tibiofibular joint recess would also be expected to become distorted if the syndesmosis was interrupted (Fig. 7). The tibiofibular recess begins above the small articular surface that joins these two bones. cavity exists above the tibiofibular connections, which end proximally at the base of the interosseous ligament. The anterior part of this cavity forms a syn- JR:182, January 2004

5 MRI of Tibiofibular Syndesmosis Injury TBLE 1 MRI Findings MRI Findings and Their ssociation with cute and Chronic Syndesmosis Injury in 94 nkles with Clinical History of Severe Sprain No Syndesmosis Injury (n = 35) Osteochondral lesions 1 11 (0.0001) 14 (0.0003) Bone bruises 4 18 (< ) 4 (0.7423) Tibiofibular joint 4 6 (0.2764) 21 (< ) incongruent Tibiofibular recess 0.54 ± ± 0.92 (< ) 1.4 ± 0.57 (< ) height (cm) Osteoarthritis (0.06) a Comparison with subgroup in first column with no syndesmosis injury. Fisher s exact test and analysis of variance test were used to quantify statistical significance. ovial recess that connects through a linear opening with the ankle joint. This recess is typically 1 cm in height [21]. lthough the recess has been identified in prior anatomic and radiographic literature, there has not been thorough documentation of the normal measurement and abnormal appearance of the recess. previous study noted that this recess becomes enlarged in patients with rheumatoid arthritis [22]. In our study, an average recess height (superior to inferior measurement) of 0.5 cm was seen in the subgroup with no syndesmosis injury, whereas average recess heights of 1.4 and 1.2 cm were measured in patients with chronic and acute syndesmosis injury, respectively. lthough the SD of these measurements was large, in a patient without inflammatory arthropathy, a tibiofibular recess height greater than 1 cm might prompt consideration of prior syndesmosis injury. Osteoarthritis was not significantly associated with syndesmosis injury in our population, although the p value approached Possibly our population was not large enough to show significance or the observed syndesmosis injuries were not associated with ankle instability or there was not enough delay after injury to detect development of osteoarthritis. Limitations of this study should be acknowledged. The retrospective study design was directed at establishing association between various MRI findings described previously. The purpose was not to associate these findings with the character of pain. Ligament injury, osteochondral lesion, osteoarthritis, and bone bruise and fracture all have been separately associated with pain, and many patients in our population had multiple findings. Therefore, attempting to separate the different findings into specific symptom patterns would be difficult in this population. cute Syndesmosis Injury (n = 23) (p) a Chronic Syndesmosis Injury (n = 36) (p) a lso, because ankle sprain is a common injury, especially in athletes, many individuals suffer recurrent injuries. Correlation of injury date with the MRI appearance would also have been limited in this population because of the potential for multiple episodes of injury with acute superimposed on chronic findings. dditionally, patients recollections of ankle sprain histories are often unreliable. In contrast, morphologic and signal changes in ligaments on MRI have been correlated with injury presence and chronicity and are quantifiable [23]. In the same regard, patients with recurrent injuries could potentially have caused overlap of findings in the acute and chronic injury subgroups; no attempt was made to create a subgroup with acute superimposed on chronic injury. Lack of this subgroup could explain the presence of bone bruises in a small proportion of patients in the chronic injury subgroup. The inability to have the reviewers blinded to the adjacent anatomic structures also limited the study. selection bias is also expected. Past studies have reported the incidence of syndesmosis injury within a range of 1 20% [3, 5, 7, 8]. In this study, 63% of the ankles had syndesmosis injuries. There are several explanations. Patients referred for MRI after ankle sprain are usually those with more severe injuries or those who do not respond as expected to conservative treatment. lternatively, because MRI can anatomically depict injury that is not clinically apparent, clinical assessments may be underestimating the true incidence of syndesmosis injury. Conversely, patients with radiographically or clinically apparent syndesmosis injury would probably have been treated acutely and are typically not referred for MRI. These theories are supported by a recent study that found a 46% incidence in their population with ankle sprain referred for MRI [14]. Several other limitations to this study include the lack of a control group. control group is difficult to create because it would consist of individuals who never had an ankle injuries; these injuries are extremely common and are often forgotten by patients. further limitation of this study is that there was no surgical follow-up; however, other studies using arthroscopy have shown the high accuracy of MRI in detecting syndesmosis injuries [12, 14]. These findings diminish the need to show surgical confirmation of the MRI findings. n additional limitation was that radiographs were not available for each MRI study to correlate findings. The volume of fluid in the tibiotalar articulation was not measured; variability of joint fluid volume in the tibiotalar articulation could possibly affect the height of the tibiofibular joint recess and might be responsible for the wide SD observed. 3D analysis of ankle joint fluid volume or MR arthrography using a standard volume might be helpful to define this relationship. In conclusion, on MRI, syndesmosis injury is associated with anterior talofibular ligament injury, osteochondral lesion, bone bruise (acute syndesmosis injury), and tibiofibular joint incongruity. References 1. Berquist TH. Foot, ankle, and calf. In: Berquist TH, ed. MRI of the musculoskeletal system. Philadelphia, P: Lippincott-Raven, 1996: Jackson DW, shley RL, Powell JW. nkle sprains in young athletes. Clin Orthop 1974;101: Gerber JP, Williams GN, Scoville CR, rciero R, Taylor DC. Persistent disability associated with ankle sprains: a prospective examination of an athletic population. Foot nkle Int 1998;19: Brosky T, Nyland J, Nitz, Caborn DNM. The ankle ligaments: consideration of syndesmotic injury and implications for rehabilitation. J Orthop Sports Phys Ther 1995;21: Hopkinson WJ, St. Pierre P, Ryan JB, Wheeler JH. Syndesmosis sprains of the ankle. Foot nkle 1990;10: Garrick JG. Epidemiologic perspective. Clin Sports Med 1982;1: Cedell C. nkle lesions. cta Orthop Scand 1975;46: Boytim MJ, Fischer D, Neumann L. Syndesmotic ankle sprains. m J Sports Med 1991;19: Katznelson, Lin E, Militiano J. Rupture of the ligaments about the tibio-fibular syndesmosis. Injury 1983;15: Taylor DC, Englehardt DL, Bassett FH. Syndesmosis sprains of the ankle: the influence of heterotopic ossification. m J Sports Med 1992;20: JR:182, January

6 Brown et al. 11. Xenos JS, Hopkinson WJ, Mulligan ME, Olson EJ, Popovic N. The tibiofibular syndesmosis: evaluation of the ligamentous structures, methods of fixation and radiographic assessment. J Bone Joint Surg m 1995;77: Vogl TJ, Hochmuth K, Diebold T, et al. Magnetic resonance imaging in the diagnosis of acute injured distal tibiofibular syndesmosis. Invest Radiol 1997;32: Muhle C, Frank LR, Rand T, et al. Tibiofibular syndesmosis: high resolution MRI using a local gradient coil. J Comput ssist Tomogr 1998;22: Oae K, Takao M, Naito K, et al. Injury of the tibiofibular syndesmosis: value of MR imaging for diagnosis. Radiology 2003;227: Farmer JM, Martin DF, Boles C, Curl WW. Chondral and osteochondral injuries: diagnosis and management. Clin Sports Med 2001;20: Bosien WR, Staples OS, Russell SW. Residual disability following acute ankle sprains. J Bone Joint Surg m 1955;37: Canale ST, Belding RH. Osteochondral lesions of the talus. J Bone Joint Surg m 1980;62: Roden S, Tillegard P, Unander-Scharin L. Osteochondritis dissecans and similar lesions of the talus: report of fifty-five cases with special reference to etiology and treatment. cta Orthop Scand 1953;23: Flick B, Gould N. Osteochondritis dissecans of the talus (transchondral fractures of the talus): review of the literature and new surgical approach for medial dome lesions. Foot nkle 1985;5: Kennedy M, Sama E, Sigman M. Tibiofibular syndesmosis and ossification: case report sequelae of ankle sprain in an adolescent football player. J Emerg Med 2000;18: Sarrafian SK. Syndesmology. In: Sarrafian SK, ed. natomy of the Foot and nkle: descriptive, topographic, functional, 2nd ed. Philadelphia, P: Lippincott Williams & Wilkins Publishers, 1993: Karasick D, Schweitzer ME, O Hara BJ. Distal fibular notch: a frequent manifestation of the rheumatoid ankle. Skeletal Radiol 1997;26: Labovitz JM, Schweitzer ME, Larka UB, Solomon MG. Magnetic resonance imaging of ankle ligament injuries correlated with time. J m Podiatr Med ssoc 1998;88: For the convenience of JR authors, a standardized form requesting permission to reprint from other publications is now available via the RRS Web site at Your computer system must have version 3.0 or later of dobe crobat Reader. 136 JR:182, January 2004