Graded stress radiography of injured anterior cruciate ligaments.

Fifty-five patients with clinical suspicion of injury to their anterior cruciate ligament (ACL) were examined by graded stress radiography before arthroscopic verification in an effort to determine the loss of ACL function as a result of ligament tearing. Using a commercially available stress device capable of applying varying pressures to the mid-calf, anterior drawers were measured from lateral radiographs at 0-, 7-, 14-, and 21-kiloPascal pressures and used to calculate the equivalent elastic modulus of the remaining ACL fibers. According to viscoelastic theory, this modulus is proportional to the number of elastically active fibers in the ligament. To verify the validity of this concept, the stress-strain relationship of a freshly excised ACL ligament was examined in a tensile testing machine, and the procedure was repeated after the ligament had been partially transsected with a scalpel. Comparison with the elastic modulus of the (intact) ACL of the opposite knee permits an estimate of the percentage of rupture in cases of partial tears. Overstretched ligaments show essentially normal viscoelastic properties once the slack in the ligament has been taken up. Complete tears, on the other hand, show a complete breakdown in the viscoelastic properties of the ACL. The results show that partial tears can be diagnosed by graded stress radiography with a sensitivity of 20% and specificity of 90%. Diagnosis of overstretched ligaments had sensitivity of 50% and specificity of 94%. Complete tears were detected with sensitivity of 88% and specificity of 75% as diagnosed against all other ACL lesions and including normals.(ABSTRACT TRUNCATED AT 250 WORDS)     

膝关节交叉韧带低场强MRI表现及其损伤诊断

目的 :研究膝关节正常交叉韧带MRI特点和交叉韧带损伤的的MRI表现。方法 :对 2 0 0例正常膝关节交叉韧带的MRI进行回顾性分析 ,对 2 5例临床可疑交叉韧带损伤患者的MRI资料和关节镜检查行对比研究。结果 :正常膝关节矢状位MRI上显示交叉韧带最佳 ,冠状位和横断位作为补充 ,交叉韧带损伤的MRI表现为韧带连续性中断、局灶性或弥漫性肿胀、信号强度增高及断端移位 ;以关节镜检查结果为标准 ,MRI诊断交叉韧带损伤的敏感度为 91.3 % ,特异度为 91.6% ,符合率为 91.4%。结论 :MRI多方位扫描是一种准确诊断交叉韧带损伤的方法 ,矢状位显示交叉韧带最佳。     

MR imaging of the most commonly injured ankle ligaments. Part II. Ligament injuries.

Thirteen patients with clinically diagnosed sprained ankles underwent magnetic resonance (MR) imaging. Five of these cases are presented to illustrate the potential of MR imaging to enable identification of both primary and associated ligament injury sites, grading of the severity of the injuries, and visualization of the associated findings of tendon sheath and joint effusion. The appropriate combination of foot position and imaging plane is essential to achieve full-length visualization of each ligament. Two patients demonstrated findings compatible with total gross disruption of the anterior fibulotalar ligament; two, with injury to the fibulocalcaneal ligament with effusion of the overlying peroneus tendon sheath; and one, with thinning, lengthening, and fibrotic changes involving the anterior fibulotalar ligament. MR imaging can provide a noninvasive means to evaluate the site and severity of ankle ligament injuries (a) in acute ankle injuries that demonstrate significant instability, (b) in stable acute injuries involving athletes or litigation, or (c) in patients with repeated injuries or instability in whom surgery is contemplated.     

MR imaging of the most commonly injured ankle ligaments. Part I. Normal anatomy.

To determine the optimum foot position and imaging plane at magnetic resonance (MR) imaging of each ankle ligament, 10 cadaver ankles were dissected to visualize the orientation, precise attachment sites, and relationships of each ligament. Then eight cadaver ankles were studied with MR imaging and were cryosectioned in the optimum imaging planes. The ankles of 12 healthy volunteers were imaged to ensure consistency in identifying the normal ligaments. With the foot taped into full dorsiflexion of 10 degrees-20 degrees, axial imaging provided optimum views of the anterior, posterior, and inferior tibiofibular ligaments and of the anterior and posterior fibulotalar ligaments and provided an overview of the deltoid ligament. Coronal images provided full-length views of the tibiospring, tibiocalcaneal, and posterior tibiotalar parts of the deltoid ligament. With the foot taped into full plantar flexion of 40 degrees-50 degrees, axial imaging optimized visualization of the fibulocalcaneal ligament and of the tibionavicular and anterior tibiotalar parts of the deltoid ligament. Sagittal images provided the best full-length views of the spring ligament.     

Graded stress radiography in acute injury to the lateral ligaments of the ankle

The diagnostic accuracy of graded stress radiography in 26 patients with acute injury to the lateral ankle ligaments has been compared with findings at arthrography and surgery. Measuring talar tilt angles and anterior talar displacement over a range of pressures applied to the distal tibia using a commercially available stress device allows diagnostic distinction between isolated anterior talofibular ligament injury and a combined lesion that involves the calcaneofibular ligament. The results compare well with arthrographic and surgical findings.     

膝关节十字韧带损伤的MRI诊断(附28例分析)

目的：提高对膝关节十字韧带损伤的认识和影像学诊断。方法：28例经手术、关节镜确诊的膝关节十字韧带损伤的患者，其中，男21例，女7例，年龄14-58岁，平均32.5岁。结果：对膝关节十字韧带损伤的MRI表现进行分析，根据韧带损伤程度分为完全性撕裂和部分性撕裂，并对慢性韧带损伤的MRI予以分析。结论：MRI是检查膝关节韧带损伤的有效方法。     

Diagnostic value of stress radiography in lesions of the lateral ligaments of the ankle

The diagnostic accuracy of inversion and anterior stress radiography in rupture of the lateral ligaments of the ankle joint was assessed in 56 patients undergoing surgery. In inversion stress radiography, 58 per cent of the patients with confirmed rupture of the lateral ligaments of the ankle had a talar tilt of 10 degrees or more, allowing a predictive value of a positive test of 94 per cent. In anterior stress radiography, 53 per cent of the patients had a posterior tibiotalar distance of 9 mm or more, allowing a predictive value of a positive test of 81 per cent. In measurements of talar tilt and anterior displacement of the talus values higher than normal in the injured ankle may be a sign of a rupture of the lateral ligament.     

Correlation between radiological assessment of acute ankle fractures and syndesmotic injury on MRI

Objective

Owing to the shortcomings of clinical examination and radiographs, injury to the syndesmotic ligaments is often misdiagnosed. When there is no indication requiring that the fractured ankle be operated on, the syndesmosis is not tested intra-operatively, and rupture of this ligamentous complex may be missed. Subsequently the patient is not treated properly leading to chronic complaints such as instability, pain, and swelling. We evaluated three fracture classification methods and radiographic measurements with respect to syndesmotic injury.

Materials and methods

Prospectively the radiographs of 51 consecutive ankle fractures were classified according to Weber, AO-Müller, and Lauge-Hansen. Both the fracture type and additional measurements of the tibiofibular clear space (TFCS), tibiofibular overlap (TFO), medial clear space (MCS), and superior clear space (SCS) were used to assess syndesmotic injury. MRI, as standard of reference, was performed to evaluate the integrity of the distal tibiofibular syndesmosis. The sensitivity and specificity for detection of syndesmotic injury with radiography were compared to MRI.

Results

The Weber and AO-Müller fracture classification system, in combination with additional measurements, detected syndesmotic injury with a sensitivity of 47% and a specificity of 100%, and Lauge-Hansen with both a sensitivity and a specificity of 92%. TFCS and TFO did not correlate with syndesmotic injury, and a widened MCS did not correlate with deltoid ligament injury.

Conclusion

Syndesmotic injury as predicted by the Lauge-Hansen fracture classification correlated well with MRI findings. With MRI the extent of syndesmotic injury and therefore fracture stage can be assessed more accurately compared to radiographs.     

The role of stress radiographs for the severe ankle sprain: A 7-year prospective study

Ankle sprains are common. They are the most common musculoskeletal injury in athletes and account for about 2 million emergency department visits annually in the United States. Although ankle radiographs are often indicated to rule out fractures of the acutely sprained ankle, the need for additional imaging work-up, such as stress radiographs, to evaluate the severity of ligamentous injury is not clear. One hundred five patients with severe ankle sprains diagnosed by stress radiographs were randomized into three conservative modes of therapy (Schantz wrap, cast brace, cast) and followed prospectively for 7 years. There was no statistically significant difference among treatment groups for mechanical outcome at 1 year (P=0.27) or for functional outcome at 5 years (P=0.39) and 7 years (P=0.27) after injury. We conclude that: (a) there currently is no recommendation for stress radiographs in the setting of the acutely sprained ankle, and (b) a larger multicenter study is needed to confirm these findings.     

Lymphocytic adenohypophysitis: skull radiographs and MRI

We report the skull radiograph, CT and MRI findings in three patients with lymphocytic adenohypophysitis mimicking pituitary adenoma. All cases were associated with pregnancy. CT demonstrated a pituitary mass but did not differentiate lymphocytic adenohypophysitis from pituitary adenoma. The skull radiographs showed either a normal sella turcica or minimal abnormalities; they did not show ballooning or destruction. The MRI appearances were distinctive: relatively low signal on T1-weighted images; preservation of the bright posterior pituitary lobe despite the presence of a relatively large pituitary mass, less common in macroadenomas; marked contrast enhancement compared with pituitary macroadenomas; and dural enhancement adjacent to a pituitary mass. Received: 12 December 1996 Accepted: 19 June 1997     

膝关节侧副韧带及其损伤的MRI研究

目的 研究正常和损伤的膝关节侧副韧带的MRI表现。方法 对经手术或临床证实的32例共36条损伤的侧副韧带与56例正常膝关节进行回顾性MRI对比观察。结果 正常胫、腓侧副韧带在T1和T2WI上均呈扁平条状低信号结构,平均长度分别为6.8cm和5.7cm。36条侧副韧带损伤,单纯胫侧副韧带损伤18条,单纯腓侧副韧带损伤12条,两侧侧副韧带同时损伤3例6条。I级侧副韧带损伤18条;Ⅱ级侧副韧带损伤11条;Ⅲ级侧副韧带损伤7条。25例（78％）出现并发症,其中前交叉韧带损伤13条、后交叉韧带损伤9条、半月板损伤12个,骨挫伤和骨折7例,关节囊积液20例。结论 MRI能清楚显示膝关节侧副韧带结构,能准确诊断侧副韧带损伤并进行分级,还能发现多种并发症,宜列为膝关节外伤的常规检查。     

Human identification from the ankle with pre- and postsurgical radiographs

Fifty-four sets of presurgical ("premortem") and postsurgical ("postmortem") foot and ankle radiographs were retrospectively evaluated to simulate a postmortem identification. The entire foot and ankle was examined in a previous study. The present study evaluates only the ankle for positive identification. Results are consistent with our earlier investigation of pre- and postsurgical foot and ankle radiographic comparisons and indicate that surgical intervention with subsequent healing does not preclude positive identification. However, the ankle contains fewer skeletal features unique to an individual than does the entire foot. Hence, the ankle may be less useful than the foot for establishing positive identification from radiographic comparisons.     

Relationship between ankle-foot swelling and self-assessed function after ankle sprain

PURPOSE: Decreasing swelling after ankle sprain is a main focus of treatment, as it is believed that swelling is related to function. The purpose of this study was to evaluate the relationship between ankle-foot swelling and self-assessed ankle function in the early period after ankle sprain. METHODS: Thirty-six individuals were tested for ankle-foot volume and self-assessed ankle function within days of spraining their ankle. Volumetric measurements of the injured and uninjured ankle-foot segment were taken with a foot and ankle volumeter. Stepwise linear regression analysis was performed, with function being the dependent variable, and the following variables included as independent variables: gender, age, body mass index, previous history of sprain in the injured ankle, and the volume difference between the injured and uninjured ankle-foot segment. RESULTS: None of the independent variables were significantly related to self-assessed function. Pearson's correlation coefficient for the injured minus uninjured ankle-foot volume and self-assessed ankle function was -0.003. CONCLUSION: The results indicate that there is no relationship between ankle-foot swelling and self-assessed ankle function in the early period after ankle sprain injury.     

MR imaging of the normal ligaments and tendons of the ankle

The 10 major ligaments and nine major tendons of the ankle were evaluated in 17 ankle MR studies to determine the incidence of visualization of each structure in each of the three orthogonal planes. High-resolution technique was used, with 3 mm slice thickness and an in-plane resolution of 0.6 mm. Of the 19 ligaments and tendons evaluated, 18 demonstrated more than 70% frequency of visualization in at least one imaging plane. However, seven ligaments and three tendons demonstrated 0% visualization in at least one of the three orthogonal planes. Seven ligaments showed more than 70% visualization in only one plane (three coronal, two axial, two sagittal). Only the Achilles tendon and anterior tibial tendon demonstrated 100% visualization in all three planes. We conclude that all three orthogonal planes are essential to achieve optimal visualization of all of the major ligaments and tendons of the ankle. For specific evaluation of selected ligaments or tendons, only one or two planes may be required.     

Intertarsal ligaments: high resolution MRI and anatomic correlation

High resolution MRI was performed on four cadaveric foot specimens of human feet to demonstrate the ligaments of the tarsal joints. Spin echo T1 images were obtained using a local gradient coil that produces 6 G/cm and 100 A in all three axes. The best views for each of the individual ligaments were determined. High resolution MRI potentially can demonstrate most of the intertarsal ligaments.