MRI与术中外旋应力试验在旋后-外旋踝关节骨折中的应用价值比较

背景：旋后-外旋骨折占所有踝关节骨折的40%~75%。其治疗方式的选择主要依赖对内侧结构损伤程度的判断,特别是内侧三角韧带是否有损伤。循证医学的资料表明,术前MR扫描与术中外旋应力试验是判断三角韧带损伤的方法。那么,术前MR扫描是否可以替代术中应力试验,明确三角韧带损伤的情况并指导踝骨折采用保守治疗或手术治疗。本文试图通过手术验证两者的敏感性是否一致。目的：探讨MRI与术中外旋应力试验在判断踝关节旋后-外旋型损伤程度中的应用价值。方法：2008年1月至2012年12月,我院收治的Lauge-Hansen分型旋后-外旋型踝关节骨折患者,共计30例,术前常规行X线、MR扫描,记录踝关节内侧三角韧带损伤情况。麻醉后行踝关节外旋应力位摄片,依据踝关节内侧间隙是否正常判定三角韧带损伤情况。再比较外旋应力试验与MR结果。结果：MR扫描对三角韧带损伤情况判定,等同于术中外旋应力试验。结论：MRI对于判断三角韧带是否损伤有一定价值,可以指导旋后-外旋型踝关节骨折不同程度损伤的鉴别与治疗方法的选择。     

Posterior Malleolus Fracture Displacement Is Associated with Rotational Ankle Fracture Stability in Patients Without Medial Malleolar Fractures

Background

The optimal method for the determination of ankle stability remains controversial in rotational ankle fractures without medial bony injury.

Questions/Purposes

The purposes of this study were to (1) evaluate whether posterior malleolar (PM) fracture displacement is associated with deltoid ligament injury in supination-external rotation (SER) ankle fractures and (2) compare the diagnostic accuracy of PM displacement and magnetic resonance imaging (MRI) evaluation of the deep deltoid ligament in identifying fractures with deltoid ligament incompetence.

Methods

Patients with rotational bimalleolar injuries containing lateral malleolar and PM fractures without bony medial injury were included. After operative lateral and PM fixation, an external rotation stress test was performed to evaluate deltoid ligament stability. Operative dictations were reviewed to confirm injury pattern, stability on stress test, and visual inspection of the deltoid ligament. Maximum PM displacement was assessed on lateral X-ray. Pre-operative MRI of the ankle was performed following closed reduction and splinting.

Results

The final cohort consisted of 13 trimalleolar equivalent fractures (torn deltoid ligament) and 20 bimalleolar fractures (medial malleolus and deltoid ligament intact). Average PM displacement was significantly higher for SER trimalleolar equivalent patterns when measured on lateral X-ray. The sensitivity of detecting trimalleolar equivalent fracture was higher on all reported X-ray findings than the sensitivity obtained by the reported MRI findings of deltoid ligament injury.

Conclusion

PM displacement on X-ray is a useful adjuvant along with external rotation stress radiography and MRI evaluation of deep deltoid integrity to distinguish between stable and unstable fracture patterns and thus helps facilitate treatment decisions.

     

Deltoid ligament integrity in lateral malleolar fractures: a comparative analysis of arthroscopic and radiographic assessments

Foot and ankle surgeons often rely on the medial clear space to evaluate competency of the deep deltoid ligament when evaluating ankle fractures. This investigation assesses the integrity of the deep deltoid ligament after lateral malleolar fracture by using direct arthroscopic visualization and medial clear-space separation on plain film radiographs. The objectives of this study were to test the reliability of medial clear-space separation and the Lauge-Hansen classification scheme in predicting deep deltoid rupture in displaced lateral malleolar fractures. The medial clear space was measured on injury radiographs of 40 patients with an isolated displaced lateral malleolar fracture who underwent open reduction and internal fixation. Injury radiographs were classified according to the Lauge-Hansen scheme. Direct arthroscopic visualization was used to evaluate the deep deltoid ligament under manual stress before fracture reduction. The mean preoperative medial clear space in patients with a deep deltoid rupture (n = 13) was 6.6 +/- 2.4 mm (range, 4 to 12 mm), and in patients without a deep deltoid rupture (n = 26), it was 4.0 +/- 1.0 mm (range, 2.5 to 6 mm) (P =.002, 2-sample t test). At an injury medial clear space > or =3 mm, the false positive rate for deltoid rupture was 88.5% (P =.54, Fisher's exact test). At > or =4 mm, the false positive rate was 53.6% (P =.007). All fractures were rotational injuries according to the Lauge-Hansen system. Three fractures were not classifiable; another 3 fractures showed deltoid ligament integrity opposite the expected finding. The results indicate that, in isolated displaced fractures of the lateral malleolus, radiographic widening of the medial clear space is not a reliable indicator for deep deltoid rupture. Some fractures considered stable by the Lauge-Hansen classification may require careful scrutiny to rule out deep deltoid injury.     

Evaluation of Lauge-Hansen Designation of Weber C Fractures

Associations between Weber C ankle fractures and pronation external rotation (PER) injuries of the Lauge-Hansen classification have often been incorrectly correlated. The purpose of the present study was to evaluate the Lauge-Hansen designation of Weber C fractures by establishing the proportion of Weber C fractures that are supination external rotation (SER), supination adduction (SA), pronation abduction (PA), PER, and hyperplantarflexion variant fractures. A clinical database of operative ankle fractures treated by the senior author (D.G.L.) was reviewed. The inclusion criteria were patient age older than 16 years, preoperative ankle radiographs, and Weber C fracture designation. A total of 132 patients met the inclusion criteria, and the proportion of PA, PER, SER, SA, and variant fractures among the Weber C fractures was analyzed. PA fractures accounted for 0.8% (n = 1), PER fractures 56.8% (n = 75), SER fractures 35.6% (n = 47), and hyperplantarflexion variant fractures 6.8% (n = 9) of the 132 Weber C fractures. Patients with Weber C-PER fractures were more commonly male (p = .005) and younger (p = .003) and demonstrated a greater fibular fracture height (p < .001) than those with Weber C-SER and Weber C-variant fractures. Our study quantitatively demonstrated that not all Weber C fractures occur secondary to pronation injuries. This distinction is important, because all pronation injuries will demonstrate medial ankle injury, but SER and variant fractures might not. We therefore recommend careful evaluation of the fibular fracture characteristics, including the direction of fracture propagation and the distance from the tibial plafond, when classifying Weber C fractures using the Lauge-Hansen system, because correct classification is vital in preparation for appropriate operative treatment.     

Competence of the deltoid ligament in bimalleolar ankle fractures after medial malleolar fixation

BACKGROUND: The stability of the ankle joint is provided by the medial and lateral malleoli and ligaments. Recent studies of cadaveric ankles have demonstrated that injury to the medial structures of the ankle is necessary to allow lateral subluxation of the talus after fracture. However, cadaveric models are limited by the fracture pattern chosen for the model. We sought to investigate the competency of the deltoid ligament in vivo in patients with an operatively treated bimalleolar ankle fracture. METHODS: Twenty-seven patients with a bimalleolar ankle fracture were evaluated. In each patient, the medial malleolus was anatomically reduced and fixed. A radiograph of the ankle was then made with application of an external rotation load to the joint. All lateral malleolar injuries were then reduced and fixed. The radiographs were evaluated for restoration of the competence of the deltoid ligament according to established criteria. RESULTS: Seven (26 percent) of the twenty-seven patients had radiographically evident incompetence of the deltoid ligament after medial malleolar fixation. This finding was associated with a small medial malleolar fragment. CONCLUSIONS: In bimalleolar fractures, the medial injury may be an osseous avulsion, leaving the deltoid intact on the displaced fragment, or it may be a combination of ligamentous and osseous injury with disruption of the deep portion of the deltoid ligament.     

The use of weightbearing radiographs to assess the stability of supination-external rotation fractures of the ankle

Background  

Isolated lateral malleolar fractures usually result from a supination-external rotation (SER) injury and may include a deltoid ligament rupture. The necessity of operative treatment is based on the recognition of a relevant medial soft-tissue disruption. Currently used tests to assess ankle stability include manual stress radiographs and gravity stress radiographs, but seem to overestimate the need for fracture fixation.     

Stable ankle joint fractures. Indications for operative or conservative treatment?

In German literature, ankle joint fractures are mostly classified in three groups according to Weber. In cases of the type A, the fracture line runs below, in cases of type B at height of the syndesmotic ligaments. C-type fractures are typically seen above this region. However, this practical and simple classification allows no inferences at accompanying injuries which in turn influence the functional outcome. We observed isolated fractures of the lateral malleolus in more than 60% of all type B-fractures, as soon as in the majority the type A-fractures. Since isolated medial ankle fractures occur very rarely, careful exclusion of further injuries is advisable here. In order to differentiate stable ones from unstable type B ankle injuries, we carry out a manual stress test, if there is less than 2 mm fracture dislocation and a congruent ankle mortise. In this manner we could find that stable lateral ankle fractures are characterized with a combination of an intact dorsal syndesmotic and medial ligament. Stable type B and undisplaced type A fractures were treated conservatively with an ankle brace (Aircast?). Unstable ankle injuries were treated by ORIF. Conservative treatment for undisplaced medial malleolar fractures is recommended, if x-rays showed less than 2 mm dislocation which allows a tibio-talare impingement. Biomechanical investigations could prove a significant increase in ankle joint stability, when an axial load of 300 N was applied to various horizontal loads. The talus does not follow automatically a displaced fibular fracture. The dorsal syndesmotic and the medial deltoid ligaments control ankle joint stability.     

旋后-外旋型踝关节骨折中三角韧带断裂的诊断与治疗

旋后-外旋型或Weber B型踝关节骨折存在稳定型和不稳定型骨折。不稳定性骨折通常在腓骨骨折的同时存在内踝的骨折或三角韧带的撕裂。现在的共识是对于不稳定型的踝关节骨折,采取切开复位内固定的方式能达到较好的临床疗效。对于内侧韧带撕裂的诊断有很多研究,但对于评估内侧韧带撕裂的最合适方法仍未达成共识。由于外旋引起的三角韧带断裂的患者数量要远比过去想象中的多。在Lauge-Hansen分型中,根据损伤的机制可以提供可能的韧带损伤的信息。通过X线的表现,运用Lauge-Hansen分型系统在评估三角韧带是否损伤具有重要的价值,但其敏感性和特异性有待考究。体格检查、应力位X线片、MRI、关节镜、B超现在已用于踝关节骨折中内侧副韧带的完整的评估,但是这些方法没有一种是便宜、简便、可靠的。现在临床医师习惯使用重力应力试验进行评估,对于可疑的病例,行关节镜探查是非常有价值的。最新的观点认为单纯腓骨骨折,可仅行腓骨骨折切开复位内固定术,对合并外踝骨折的三角韧带撕裂进行修复是没有意义的,也没有证据证明暴露并修复三角韧带对内踝结构有影响。     

Ultrasonographic examination of the deltoid ligament in bimalleolar equivalent fractures

BACKGROUND: Lauge-Hansen supination-external rotation Stage IV ankle injuries may simulate a Stage II or Stage III injury radiographically if the medial disruption occurred through the deltoid ligament instead of the medial malleolus, making it difficult to determine whether an operation is indicated. MATERIALS AND METHODS: Seventeen patients presented with radiographically isolated lateral malleolar fractures at the syndesmotic level. They were examined with ultrasonography for evaluation of the integrity of the deltoid ligament. Patients in whom ultrasonography showed complete rupture of the deltoid ligament received operative fixation of the ankle fracture, with exploration and repair of the deltoid ligament at the same time. Patients without complete rupture of the deltoid ligament were treated conservatively with a short leg cast for 6 weeks followed by an ankle brace for another 6 weeks. Nine male and six female patients completed the final clinical and radiographic evaluations. RESULTS: Ultrasonography showed complete rupture of the deltoid ligament in six patients. Exploration of the deltoid ligaments confirmed the sonographic findings in all these patients. In the remaining nine patients, the deltoid ligaments were not completely ruptured on ultrasound. These fractures were treated conservatively, and all healed uneventfully. All the 15 patients had good or fair results on the final evaluation. CONCLUSION: Ultrasonography is a convenient and accurate diagnostic tool to differentiate unstable bimalleolar-equivalent ankle fractures from an isolated lateral malleolar fracture. Thus, it can be helpful in the decision process for the treatment of choice for different fracture patterns.     

Does medial tenderness predict deep deltoid ligament incompetence in supination-external rotation type ankle fractures?

OBJECTIVE: To identify whether medial tenderness is a predictor of deep deltoid ligament incompetence in supination-external rotation ankle fractures. DESIGN: All Weber B lateral malleolar fractures with normal medial clear space over a 9 month period were prospectively included in the study. Fracture patterns not consistent with a supination-external rotation mechanism were excluded. SETTING: High-volume tertiary care referral center and Level I trauma center. PATIENTS/PARTICIPANTS: Fifty-five skeletally mature patients with a Weber B lateral malleolar fracture and normal medial clear space presenting to our institution were included. INTERVENTION: All study patients had ankle anteroposterior, lateral, and mortise radiographs. Each patient was seen and evaluated by an orthopedic specialist and the mechanism of injury was recorded. Each patient was assessed for tenderness to palpation in the region of the deltoid ligament and then had an external rotation stress mortise radiograph. MAIN OUTCOME MEASURE: Correlating medial tenderness with deep deltoid competence as measured by stress radiographs. RESULTS: Thirteen patients (23.6%) were tender medially and had a positive external rotation stress radiograph. Thirteen patients (23.6%) were tender medially and had a negative external rotation stress radiograph. Nineteen patients (34.5%) were nontender medially and had a negative external rotation stress radiograph. Ten patients (18.2%) were nontender medially and had a positive external rotation stress radiograph. We calculated a chi statistic of 2.37 as well as the associated P value of 0.12. Medial tenderness as a measure of deep deltoid ligament incompetence had a sensitivity of 57%, a specificity of 59%, a positive predictive value of 50%, a negative predictive value of 66%, and an accuracy of 42%. CONCLUSION: There was no statistical significance between the presence of medial tenderness and deep deltoid ligament incompetence. There is a 25% chance of the fracture in question with medial tenderness having a positive external rotation stress and a 25% chance the fracture with no medial tenderness having a positive stress test. Medial tenderness in a Weber B lateral ankle fracture with a normal clear space on standard plain radiographs does not ensure the presence of a positive external rotation stress test.     

Comparison of manual and gravity stress radiographs for the evaluation of supination-external rotation fibular fractures

BACKGROUND: Isolated distal fibular fractures most commonly result from a supination-external rotation injury of the ankle. Deltoid ligament ruptures can also be associated with these injuries, resulting in an unstable ankle fracture due to incompetent lateral and medial restraints. We hypothesized that a gravity stress radiograph is equivalent to a manual stress radiograph for the detection of deltoid ligament injury in association with an isolated fibular fracture. METHODS: All patients presenting to a level-1 trauma hospital emergency department with an isolated fibular fracture were screened. Ankle stability was determined on the basis of radiographic measurements of the medial clear space and talar shift. A manual stress radiograph and a gravity stress radiograph of the injured ankle were made for each patient. The manual stress radiograph was used to determine whether the ankle was stable or unstable. RESULTS: A total of twenty-five patients (thirteen with a supination-external rotation type-II fracture and twelve with a supination-external rotation type-IV-equivalent injury) were enrolled in the study. In the type-II group, the average medial clear space was 4.15 and 4.26 mm on the manual and gravity stress radiographs, respectively (p = 0.50). In the type-IV group, the average medial clear space was 5.21 and 5.00 mm on the manual and gravity stress radiographs, respectively (p = 0.69). CONCLUSIONS: The gravity stress radiograph is equivalent to the manual stress radiograph for determining deltoid ligament injury in association with an isolated distal fibular fracture, and thus it can be used to determine ankle stability in patients who present with an isolated distal fibular fracture.     

Stress examination of supination external rotation-type fibular fractures

BACKGROUND: Deltoid incompetence in association with an isolated fibular fracture is assumed to be present if there is medial tenderness, ecchymosis, or substantial swelling. We sought to determine whether these soft-tissue indicators predict deltoid incompetence by comparing such findings with the findings on stress radiographs. METHODS: Over a thirty-two-month period, 138 patients who presented acutely with a Weber type-B supination-external rotation (SE) fibular fracture were evaluated for tenderness (in nine locations), ecchymosis, and swelling. Patients who presented with an apparently isolated fibular fracture and an intact ankle mortise (with a medial clear space of < or =4 mm and no talar subluxation) were evaluated with a stress radiograph to determine deltoid competence. Four groups of patients were identified: those who had an SE2 fracture (defined as those who had a stable ankle on the stress radiograph), those who had a stress (+) SE4 fracture (defined as those who had an unstable ankle on the stress radiograph), those who had an SE4 fracture (defined as those who presented with a wide medial clear space), and those who had a bimalleolar fracture. These four groups were compared with regard to tenderness, swelling, and ecchymosis at the time of initial presentation. Patients with SE2 injuries were allowed immediate weight-bearing. RESULTS: Of the ninety-seven patients who presented with an isolated fibular fracture and an intact mortise, sixty-one had a stable SE2 injury and thirty-six had an unstable stress (+) SE4 injury. All stable SE2 injuries healed with an intact mortise. Medial tenderness, ecchymosis, and swelling were not predictive of deltoid incompetence (instability). CONCLUSIONS: Stress radiographs allow for the accurate diagnosis of deltoid incompetence in patients with Weber type-B SE fibular fractures and no other osseous injury. Soft-tissue indicators are not accurate predictors of instability. If medial tenderness, ecchymosis, and swelling are used as operative indications, in some cases surgery may be performed on stable ankles.     

Evaluation of the integrity of the deltoid ligament in supination external rotation ankle fractures: a systematic review of the literature

Background and purpose  Review the literature concerning modalities to evaluate the integrity of the deltoid ligament in patients with supination external rotation ankle fractures. Methods  The electronic databases Pubmed/Medline, CINAHL and Embase were searched from 1987 to November 2007 to identify all published original studies concerning diagnostic modalities to evaluate the integrity of the deltoid ligament in adult ankle fractures. Results  This review included nine studies involving 423 ankle fractures. Three trails investigated medial tenderness; two studies, ecchymosis; two studies, swelling; one study, an injury radiograph; six studies, a type of radiographic stress view; one study, the Lauge-Hansen classification; one study, MRI; and one article studied arthroscopy in the evaluation of the deltoid ligament integrity. Interpretation  Swelling, ecchymosis, medial tenderness, initial injury radiographs and the Lauge-Hansen classification are less adequate predictors of the integrity of the deltoid ligament. Manual or the less painful variant, the gravity external rotation stress radiographs are considered the gold standard. The amount of medial clear space widening indicative of a positive external rotation stress test has been somewhat variable in the literature but ≥5 mm is generally regarded as most reliable. Achieving adequate external rotation of the foot when obtaining stress radiographs is more important than positioning the ankle in the appropriate degree of ankle flexion. The amount of applied force necessary when performing an external rotation stress radiograph is not well defined and mainly determined by the patient’s pain level. The indication for surgery should not be based on the absolute value of one parameter but on the combination of several parameters. If nonoperative treatment is chosen despite a positive stress radiograph, close follow-up is critical because subluxation of the ankle joint is still possible. MRI could be useful in individual cases.     

踝关节旋后外旋、旋前外旋Ⅳ型骨折三角韧带修复效果比较

目的比较旋后外旋(SER)Ⅳ型、旋前外旋(PER)Ⅳ型踝关节骨折三角韧带断裂修复治疗的治疗效果。 方法回顾性分析首都医科大学宣武医院骨科于2016年1月至2018年1月收治的SER、PER Ⅳ型踝关节骨折患者。纳入标准：三角韧带断裂;随访超过1年。排除标准：年龄≥70岁、踝关节存在陈旧性损伤、内踝骨折、同侧下肢其他部位骨折、开放性骨折、无法配合功能锻炼、病理性骨折。按照纳入排除标准,共有68例纳入本研究,SER组47人,PER组21人。评估两组患者术后1年后的踝关节美国足踝外科协会(AOFAS)评分、生活质量(QOL)评分,采用t检验比较两组之间的差异。 结果SER组患者的踝关节功能恢复情况优于PER组(t＝8.314,P<0.05);SER组的躯体健康优于PER组患者(t＝0.766,P<0.05)、但精神健康方面两组患者基本一致(t＝0.452,P>0.05),合计SF-36的总分后,发现两组患者的QOL无明显差异(t＝0.172,P>0.05)。 结论踝三角韧带断裂行修复后,SER Ⅳ型骨折患者的踝关节功能恢复情况、躯体QOL比PER Ⅳ型患者好,但是两组患者的精神健康QOL、总体QOL基本一致。     

外踝骨折后三角韧带损伤程度的X线与MRI比较研究

目的 探讨急性外踝骨折后X线片与MRI评价三角韧带损伤程度的影像学诊断价值.方法 总结医院PACS系统中41例急性外踝骨折(排除合并内踝骨折病例)的X线片和MR影像资料,于踝穴位X线片上测量踝内侧间隙(medial clear space,MCS)宽度,应用MR影像对三角韧带深层(胫距后韧带)及浅层(胫弹簧韧带和胫跟韧带)损伤进行评价分级,统计分析MCS与三角韧带损伤程度的相关性;分别记录以X线片和MRI为参考的全部病例Lauge-Hansen分型.结果 MCS与三角韧带损伤等级呈正相关,经ROC曲线分析,判定三角韧带完全断裂(深层和浅层同时)的MCS最适临界值和深层单独完全断裂的MCS最适临界值均为7.85 mm;而判断浅层完全断裂的MCS最适临界值是6.48mm;以MRI为金标准,所有病例Lauge-Hansen分型的准确性为58.5％,但预测三角韧带断裂的准确性达82.9％,只是难以区分深层和(或)浅层断裂.结论 急性外踝骨折后即使未出现内踝骨折,也常伴有三角韧带损伤,X线片仍是踝关节骨折评价的首选检查技术,而MR检查是明确三角韧带损伤程度的敏感辅助检查技术.     

The ability of the Lauge-Hansen classification to predict ligament injury and mechanism in ankle fractures: an MRI study

OBJECTIVES: The Lauge-Hansen classification system was designed to predict the mechanism and ligament injury patterns of ankle fractures on the basis of x-rays. The purpose of this study was to evaluate the accuracy of these predicted injury sequences using magnetic resonance imaging (MRI) in a series of patients with ankle fractures. DESIGN: Retrospective cohort. SETTING: Two university level 1 trauma centers. PATIENTS: Fifty-nine patients with operative ankle fractures who were evaluated with both x-ray and MRI were included. INTERVENTION: All patients had a standard 3-view ankle x-ray series before fracture reduction, followed by an MRI. All plain x-rays were assigned to a Lauge-Hansen category by an experienced orthopedic traumatologist. MRI studies were subsequently read by an MRI musculoskeletal radiologist for the integrity of the ankle ligaments. MAIN OUTCOME MEASUREMENTS: After evaluation of the x-rays, fractures were classified according to the system of Lauge-Hansen, and the predicted presence, sequence, and mechanism of injury was determined. These were then compared to the actual injured structures on MRI in each case, and the ability of the Lauge-Hansen system to accurately predict the complete injury pattern was determined for the entire cohort. RESULTS: Average patient age was 59 (range: 18 to 84) years. Of the 59 ankle fractures evaluated, 37 (63%) were classified as supination external rotation, 11 (19%) were pronation external rotation, 1 (2%) was supination adduction, and 10 (17%) were not classifiable on the basis of the Lauge-Hansen system. Of the 49 fractures that fit into Lauge-Hansen categories, 26 (53%) had patterns of ligamentous injury and fracture morphology that did not coincide with the Lauge-Hansen predictions. A common fracture pattern was observed in 8 of the 10 unclassifiable fractures, which included a high spiral fracture of the fibula, vertical shear fracture of the medial malleolus, posterior malleolar fracture, and complete tears of the anterior-inferior tibiofibular ligament and the interosseous membrane. In addition, over 65% of patients in this series had complete ligamentous injury and a fracture of the malleolus to which the ligament attaches. CONCLUSIONS: These results demonstrate that the Lauge-Hansen classification system may have some limitations as a predictor of the mechanism of injury and the presence of soft-tissue damage associated with ankle fractures. The identification of a novel pattern of ankle fracture also illustrates how the system fails to describe all possible fracture patterns. For these reasons, we recommend that the Lauge-Hansen system be used only as a guide in the diagnosis and management of ankle fractures and not solely relied upon for treatment decisions. Although the exact clinical implications of the variety of ligamentous injuries observed on MRI are yet to be determined, this technique may be useful in individual cases in which doubt about joint stability and soft-tissue integrity exists. Additionally, MRI may be helpful in planning surgical approaches in atypical fractures in which injury patterns are less predictable solely on the basis of x-ray.     

The role of the tibiofibular syndesmotic and the deltoid ligaments in stabilizing Weber B type ankle joint fractures--an experimental investigation

The purpose of the present biomechanical investigation was to check the functional importance of the syndesmosis ligaments and of the deltoid ligament for ankle fracture type B according to the AO-Weber classification. We constructed a special fixation clamp, with 12 fresh and unembalmed lower legs being tested for lateral shift (mm) and ten for tibiotalar rotation. All specimens were exposed in the same neutral position.Transverse loads (F(y)) varied between 0 and 150 N, axial loads (F(z)) between 0, 300, 600 and 1,000 N and rotational loads (F(r)) between 2.4 and 4.9 Nm. All series were repeated according to supination-eversion (SE) injury patterns of the Lauge-Hansen classification. Syndesmotic ligaments and the fibula were incrementally sectioned from anterior to posterior. Type SE I consisted of an isolated incision of the anterior syndesmosis ligament. Type SE II had an additional oblique fracture of the fibula at the height of the tibiofibular syndesmosis. In type SE III injuries, in addition to the fibular fracture, a complete rupture of the syndesmosis ligaments was present, and for type SE IV lesions the deltoid ligaments were incised.The transverse load-displacement curve was s-shaped in all uninjured joints,with the highest gradient between 10 and 20 N with no axial compression. Without axial compression in cases of F(y)=25 N transverse loads, the mean talus translation was 0.51 mm. Following type II injuries, the average talus translation was 0.68 mm (not significant) and rose to an average of 0.95 mm ( P <0.01) in type III injuries. After additional incision of the deltoid ligaments, the ankle joint subluxed permanently when more than 5-10 N transverse loads were applied. Axial loads of 300 N or more resulted in a considerable reduction in talus translations, indicating increased stability and congruency within the joint complex. In this way, the vertical loading of the ankle joints always contributed to joint stability. The average internal tibiotalar rotation reached with a torque of 2.4 Nm was 3.52 degrees and with 4.9 Nm 5.15 degrees when no axial compression was applied.External rotation measured -6.36 degrees and -8.62 degrees, respectively. Following the experimental protocol, significant increases were noted for external rotation at SE II degrees injuries ( P =0.003) and for internal rotation at SE III degrees ( P =0.03) injuries. Our data support the proposition that the deltoid ligaments and the posterior syndesmosis play a key role in the stability of ankle fractures for supination-eversion injuries. If these structures remain intact, conservative and early functional treatment are recommended in patients with minimal (<2 mm) or no fracture displacement. This concept is confirmed by the literature dealing with clinical mid- and long-term follow-up studies.     

Supination trauma. A classic case

Sprains in the lateral ligaments of the ankle produce the most common ligamentous injuries of the human body. The mechanism of injury is complex, while supination represents the main component of foot movement. Classifying lateral ankle ligament injuries, many authors use a system of three degrees, which includes mild, moderate and severe sprains. Despite this scientific categories, in our opinion is the differentiation between elongation and complete ruptures of practical relevance. Under a biomechanical point of view, ligamentous trauma of the lateral ligaments lead to acute antero-lateral rotational instability (ALRI). Following the retrospective clinical study of Zwipp with 1,235 patients, in 70% of complete disruptions, the anterior talo-naviculare and fibulocalcanear ligaments are involved together. Syndesmotic injuries have been reported at a rate up to 10% of ankle sprains with deltoid ligaments at 2.5%. Rarely, the classic ankle sprain leads to injuries which affect the foot on a so called "supination fracture line". A rate of 7.4% is reported for these accompanying injuries. Therefore, clinical examination of ankle sprains should not only address on the distal tip of the fibula. Critical bony and ligamentous structures like the fifth metatarsal base, the calcaneo-cuboideal ligament, the ligaments of the anterior calcaneal process, the talus and syndesmotic ligaments have to be screened for pain and swelling. In our opinion, careful clinical examination and plain radiographs in two plains are sufficient for diagnosing ankle sprains and functional therapy.     

Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

BackgroundWe assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes.MethodsFifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity.ResultsThe patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome.ConclusionsPosterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to undergo surgical repairs.