Injury of the tibiofibular syndesmosis: value of MR imaging for diagnosis

Post-traumatic heterotopic ossification of distal tibiofibular syndesmosis mimicking a surface osteosarcoma

AIM

To present the imaging features of post-traumatic heterotopic ossification (HO) of the distal tibiofibular syndesmosis initially suspected to be a surface osteosarcoma.

MATERIALS AND METHODS

A retrospective review was conducted of the presenting complaint and imaging features of patients with a final diagnosis of HO referred over an 8 year period to a specialist orthopaedic oncology centre.

RESULTS

Five patients with HO were identified. All were adult males with an age range of 19-41 years. There was a history of prior ankle trauma in all cases but the significance was not recognized at the time of referral to the specialist centre. There was radiographic evidence of HO arising from the inner aspects of the distal tibia and fibula approximately 3 cm proximal to the ankle joint. The HO was "kissing" in two cases and partially fused (synostosis) in two. The HO in the fifth case was arising on the inner fibular cortex alone. Magnetic resonance imaging (MRI), available in four cases, showed predominantly low signal intensity due to the dense bone formation.

CONCLUSION

The history of prior ankle trauma with ossification arising from the inner aspects of both the distal tibia and fibula is typical of post-traumatic HO and distinguish this benign condition from the rare surface osteosarcoma at this site.

The role of ankle arthroscopy in acute ankle injuries of the athlete

This article discusses the role of ankle arthroscopy in the acute management of ankle trauma in athletes. The rate of intra-articular pathology associated with ankle trauma is high and arthroscopic treatment often has an important role to play. Its major role is in the assessment and treatment of joint surface damage, syndesmotic instability, and intra-articular fractures.

Syndesmosis and deltoid ligament injuries in the athlete

PURPOSE

Injury to the syndesmosis and deltoid ligament is less common than lateral ligament trauma but can lead to significant time away from sport and prolonged rehabilitation. This literature review will discuss both syndesmotic and deltoid ligament injuries without fracture in the professional athlete.

METHODS

A narrative review was performed using PUBMED, OVID, MEDLINE and EMBASE using the key words syndesmosis, injury, deltoid, ankle ligaments, and athlete. Articles related to the topic were included and reviewed.

RESULTS

The incidence of syndesmotic injury ranges from 1 to 18 % of ankle sprains. This may be underreported and is an often missed injury as clinical examination is generally not specific. Both MRI and ultrasonography have high sensitivities and specificities in diagnosing injury. Arthroscopy may confirm the diagnosis, and associated intra-articular pathology can be treated at the same time as surgical stabilization. Significant deltoid ligament injury in isolation is rare, there is usually associated trauma. Major disruption of both deep and superficial parts can lead to ankle dysfunction. Repair of the ligament following ankle fracture is not necessary, but there is little literature to guide the management of deltoid ruptures in isolation or in association with syndesmotic and lateral ligament injuries in the professional athlete.

CONCLUSION

Management of syndesmotic injury is determined by the grade and associated injury around the ankle. Grade I injuries are treated non-surgically in a boot with a period of non-weight bearing. Treatment of Grade II and III injuries is controversial with little literature to guide management. Athletes may return to training and play sooner if the syndesmosis is surgically stabilized. For deltoid ligament injury, grade I and II sprains should be treated non-operatively. Unstable grade III injuries with associated injury to the lateral ligaments or the syndesmosis may benefit from operative repair.

Standardization of the functional syndesmosis widening by dynamic U.S examination

Background

Dynamic US examination is a convenient, accurate, inexpensive and reproducible diagnostic tool for assessing the integrity of the distal tibiofibular syndesmosis in ankle injuries. However normal values for physiological functional widening of the anterior tibiofibular clear space in healthy subjects has yet to be determined. The purpose of this study was to determine normal values for the syndesmosis clear space on ultrasound examination.

Methods

We evaluated 110 healthy subjects. A dynamic U.S examination was performed in neutral (N), forced internal rotation (IR) and external rotation (ER) of the ankle. In each position the anterior tibiofibular clear space was measured at the level of the anterior inferior tibio-fibular ligament (AITFL). Height and calf length were also recorded. Results were analyzed in relation to age, activity, dominant leg and gender.

Results

Mean age was 32 years (range 16–60). There were 59 males and 51 females. 60% were professional athletes. Mean height was 173 cm (range 149–192). Functional Mean position measurements for clear space opening were: N=3.7mm, IR=3.6mm and ER=4.0mm. In younger men and women the clear space was significantly wider in neutral (Men: Y=3.8, O=3.4 \ Women: Y=3.8, O=3.4) and with rotational force application (Men ER: Y=4.1, O=3.6 \ Women ER: Y=4.1, O=3.8) compared to older subjects (p<0.05). There was no correlation with activity, height or the leg length.

Females had a higher syndesmosis widening ratio (ER/N) under stress than males (p<0.01) this tended to occur more commonly in active subjects.

Conclusions

Normal values for the syndesmosis clear space on ultrasound examination were determined as 3.78mm in neutral, 3.64mm in internal rotation and 4.08mm in external rotation. The clear space was shown to decrease with age both as an absolute measure and when rotational stresses are applied. Females tend to have a larger clear space and a greater functional widening.

These findings provide a useful reference for radiologists and sports physicians when performing ultrasound assessment of ankle syndesmotic injuries and we encourage use of this modality.

Dynamically unstable syndesmosis injuries

Distal tibiofibular syndesmosis injuries are complex injuries that often result in extended loss of playing time for athletes. Unstable syndesmosis injuries are uniformly reduced and stabilized by numerous methods. Controversy arises from syndesmosis injuries that are stable on stress radiographs but functionally unstable with loading of the ankle during athletic activity. The authors present a case of operative fixation of a dynamically unstable syndesmosis and detail the postoperative course.

False negative rate of syndesmotic injury in pronation-external rotation stage IV ankle fractures

BACKGROUND

To investigate false negative rate in the diagnosis of diastasis on initial static anteroposterior radiograph and reliability of intraoperative external rotational stress test for detection of concealed disruption of syndesmosis in pronation external rotation (PER) stage IV (Lauge-Hansen) ankle fractures.

MATERIALS AND METHODS

We prospectively studied 34 PER stage IV ankle fractures between September 2001 and September 2008. Twenty (59%) patients show syndesmotic injury on initial anteroposterior radiographs. We performed an intraoperative external rotation stress test in other 14 patients with suspicious PER stage IV ankle fractures, which showed no defined syndesmotic injury on anteroposterior radiographs inspite of a medial malleolar fracture, an oblique fibular fracture above the syndesmosis and fracture of the posterior tubercle of the tibia.

RESULTS

All 14 fractures showed different degrees of tibiofibular clear space (TFCS) and tibiofibular overlapping (TFO) on the external rotation stress test radiograph compared to the initial plain anteroposterior radiograph. It is important to understand the fracture pattern characterstic of PER stage IV ankle fractures even though it appears normal on anteroposterior radiographs, it is to be confirmed for the concealed syndesmotic injury through a routine intraoperative external rotational stress radiograph.

Diagnostic accuracy of clinical tests for diagnosis of ankle syndesmosis injury: a systematic review

OBJECTIVES

To determine the value of clinical tests for accurate diagnosis of ankle syndesmosis injury.

DESIGN

Systematic review.

DATA SOURCES

An electronic database search was conducted (to 6 August 2012) of databases such as: MEDLINE, CINAHL, EMBASE, PubMed and Cochrane Databases. References from identified articles were examined and seven authors of eligible studies were contacted for additional information.

STUDY SELECTION

Studies of any design, without language restriction, were included; however, systematic reviews were excluded. Eligible studies included participants with a suspected ankle syndesmosis injury but without fracture. Reliability studies compared one or more clinical tests and studies of test accuracy compared the clinical test with a reference standard.

RESULTS

The database search resulted in 114 full text articles which were assessed for eligibility. Three studies were included in the review and raw data of these studies were retrieved after contacting the authors. Eight clinical diagnostic tests were investigated; palpation of the tibiofibular ligaments, external rotation stress test, squeeze, Cotton, fibula translation, dorsiflexion range of motion (ROM) and anterior drawer tests. Two studies investigated diagnostic accuracy and both investigated the squeeze test by with conflicting results. Likelihood ratios (LR) ranging from LR+1.50 to LR-1.50 were found for other tests. High intra-rater reliability was found for the squeeze, Cotton, dorsiflexion ROM and external rotation tests (83-100% close agreement). Inter-rater reliability was good for the external rotation test (ICC2,1>0.70). Fair-to-poor reliability was found for other tests.

CONCLUSIONS

This is the first systematic review to investigate the reliability and accuracy of clinical tests for the diagnosis of ankle syndesmosis injury. Few studies were identified and our findings show that clinicians cannot rely on a single test to identify ankle syndesmosis injury with certainty. Additional diagnostic tests, such as MRI, should be considered before making a final diagnosis of syndesmosis injury.

Intra-articular lesions in chronic lateral ankle instability: comparison of arthroscopy with magnetic resonance imaging findings

BACKGROUND

Chronic lateral ankle instability often accompanies intra-articular lesions, and arthroscopy is often useful in diagnosis and treatment of intra-articular lesions.

METHODS

Preoperative magnetic resonance imaging (MRI) examinations and arthroscopic findings were reviewed retrospectively and compared in 65 patients who underwent surgery for chronic lateral ankle instability from January 2006 to January 2010. MR images obtained were assessed by two radiologists, and the inter- and intra-observer reliability was calculated. American Orthopedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS) scores were evaluated.

RESULTS

Abnormalities of the anterior talofibular ligament (ATFL) were found in all 65 (100%) cases. In arthroscopy examinations, 33 (51%) cases had talar cartilage lesions, and 3 (5%) cases had 'tram-track' cartilage lesion. Additionally, 39 (60%) cases of synovitis, 9 (14%) cases of anterior impingement syndrome caused by osteophyte, 14 (22%) cases of impingement syndrome caused by fibrotic band and tissue were found. Sensitivity of MRI examination for each abnormality was: ATFL, 60%; osteochondral lesion of talus (OLT), 46%; syndesmosis injury, 21%; synovitis, 21%; anterior impingement syndrome caused by osteophyte, 22%. Paired intra-observer reliability was measured by a kappa statistic of 0.787 (95% confidence interval [CI], 0.641 to 0.864) for ATFL injury, 0.818 (95% CI, 0.743 to 0.908) for OLT, 0.713 (95% CI, 0.605 to 0.821) for synovitis, and 0.739 (95% CI, 0.642 to 0.817) for impingement. Paired inter-observer reliability was measured by a kappa statistic of 0.381 (95% CI, 0.241 to 0.463) for ATFL injury, 0.613 (95% CI, 0.541 to 0.721) for OLT, 0.324 (95% CI, 0.217 to 0.441) for synovitis, and 0.394 (95% CI, 0.249 to 0.471) for impingement. Mean AOFAS score increased from 64.5 to 87.92 (p < 0.001) when there was no intra-articular lesion, from 61.07 to 89.04 (p < 0.001) in patients who had one intra-articular lesion, and from 61.12 to 87.6 (p < 0.001) in patients who had more than two intra-articular lesions.

CONCLUSIONS

Although intra-articular lesion in patients with chronic lateral ankle instability is usually diagnosed with MRI, its sensitivity and inter-observer reliability are low. Therefore, arthroscopic examination is strongly recommended because it improved patients' residual symptoms and significantly increased patient satisfaction.

Rehabilitation of syndesmotic (high) ankle sprains

CONTEXT

High ankle sprains are common in athletes who play contact sports. Most high ankle sprains are treated nonsurgically with a rehabilitation program.

EVIDENCE ACQUISITION

All years of PUBMED, Cochrane Database of Systematic Reviews, CINAHL PLUS, SPORTDiscuss, Google Scholar, and Web of Science were searched to August 2010, cross-referencing existing publications. Keywords included syndesmosis ankle sprain or high ankle sprain and the following terms: rehabilitation, treatment, cryotherapy, braces, orthosis, therapeutic modalities, joint mobilization, massage, pain, pain medications, TENS (ie, transcutaneous electric nerve stimulation), acupuncture, aquatic therapy, strength, neuromuscular training, perturbation training, and outcomes.

RESULTS

Level of evidence, 5. A 3-phase rehabilitation program is described. The acute phase is directed at protecting the joint while minimizing pain, inflammation, muscle weakness, and loss of motion. Most patients are treated with some form of immobilization and have weightbearing restrictions. A range of therapeutic modalities are used to minimize pain and inflammation. Gentle mobilization and resistance exercises are used to gain mobility and maintain muscle size and strength. The subacute phase is directed at normalizing range of motion, strength, and function in activities of daily living. Progressive mobilization and strengthening are hallmarks of this phase. Neuromuscular training is begun and becomes the central component of rehabilitation. The advanced training phase focuses on preparing the patient for return to sports participation. Perturbation of support surfaces, agility drills, plyometrics, and sport-specific training are central components of this phase.

CONCLUSION

The rehabilitation guidelines discussed may assist clinicians in managing syndesmotic ankle sprains.

Intraoperative three-dimensional imaging in the treatment of acute unstable syndesmotic injuries

BACKGROUND

Acute unstable syndesmotic ankle injuries are treated primarily by reduction and stabilization with a syndesmotic screw. Examination with fluoroscopy or standard radiographs may not provide reliable information about the quality of the reduction. There is evidence that intraoperative three-dimensional imaging can demonstrate a large proportion of malreductions. The aim of this study was to determine whether intraoperative three-dimensional imaging improves the detection of inadequate positioning of the distal aspect of the fibula in the tibiofibular incisura after syndesmotic screw insertion compared with the findings on standard intraoperative fluoroscopy.

METHODS

Of 2286 ankle fractures treated operatively from August 2001 to February 2011, 251 consecutive cases (11%) were identified in a retrospective chart review. All had an unstable syndesmosis and underwent syndesmosis stabilization on the basis of an intraoperative hook test. After fluoroscopy, an intraoperative three-dimensional scan was performed. The result of this scan was documented by the surgeon and analyzed retrospectively with regard to the incidence and nature of the need for intraoperative revisions.

RESULTS

The intraoperative three-dimensional scan altered the surgical outcome in eighty-two ankles (32.7%). In most ankles (seventy-seven; 30.7%), the reduction was improved, with the most common improvement being the alignment of the fibula in the tibiofibular incisura in sixty-four patients (25.5%) followed by correction of the fracture reduction in thirteen patients (5.2%). The other five alterations involved implant corrections. The most common malpositions requiring correction after insertion of a positioning screw, with or without additional fixation, were anterior displacement and internal rotation of the distal aspect of the fibula.

CONCLUSIONS

Following open reduction and internal fixation of an ankle fracture, the correct position of the syndesmosis cannot be evaluated reliably with use of conventional radiographs or intraoperative fluoroscopy. In view of the high proportion of positive findings in this study, we believe that any treatment of a syndesmotic injury should include intraoperative three-dimensional imaging or at least a postoperative computed tomography scan.

Isolated chronic anteroinferior tibiofibular ligament rupture repair

Chronic anteroinferior tibiofibular ligament tears are rarely an isolated pathology. Only a small amount of published, peer-reviewed literature exists describing the isolated repair of the syndesmotic complex in patients who present with chronic ankle pain. We present a technique to restore the anatomic stability of the ligament and syndesmotic complex. The procedure can be easily performed using allogenic semitendinosus tendon graft and stabilized with transyndesmotic screws. The graft can be secured with biotenodesis screws or anchors of the surgeon's preference. The patient described in this report had a successful outcome with no complications.

Distal tibiofibular radiological overlap: Does it always exist?

OBJECTIVES

Overlap between the distal tibia and fibula has always been quoted to be positive. If the value is not positive then an injury to the syndesmosis is thought to exist. Our null hypothesis is that it is a normal variant in the adult population.

METHODS

We looked at axial CT scans of the ankle in 325 patients for the presence of overlap between the distal tibia and fibula. Where we thought this was possible we reconstructed the images to represent a plain film radiograph which we were able to rotate and view in multiple planes to confirm the assessment.

RESULTS

The scans were taken for reasons other than pathology of the ankle. We found there was no overlap in four patients. These patients were then questioned about previous injury, trauma, surgery or pain, in order to exclude underlying pathology.

CONCLUSION

We concluded that no overlap between the tibia and fibula may exist in the population, albeit in a very small proportion.

Diagnosis and treatment of acute ankle injuries: development of an evidence-based algorithm

Acute ankle injuries are among the most common injuries in emergency departments. However, there are still no standardized examination procedures or evidence-based treatment. Therefore, the aim of this study was to systematically search the current literature, classify the evidence, and develop an algorithm for the diagnosis and treatment of acute ankle injuries. We systematically searched PubMed and the Cochrane Database for randomized controlled trials, meta-analyses, systematic reviews or, if applicable, observational studies and classified them according to their level of evidence. According to the currently available literature, the following recommendations have been formulated: i) the Ottawa Ankle/Foot Rule should be applied in order to rule out fractures; ii) physical examination is sufficient for diagnosing injuries to the lateral ligament complex; iii) classification into stable and unstable injuries is applicable and of clinical importance; iv) the squeeze-, crossed leg- and external rotation test are indicative for injuries of the syndesmosis; v) magnetic resonance imaging is recommended to verify injuries of the syndesmosis; vi) stable ankle sprains have a good prognosis while for unstable ankle sprains, conservative treatment is at least as effective as operative treatment without the related possible complications; vii) early functional treatment leads to the fastest recovery and the least rate of reinjury; viii) supervised rehabilitation reduces residual symptoms and re-injuries. Taken these recommendations into account, we present an applicable and evidence-based, step by step, decision pathway for the diagnosis and treatment of acute ankle injuries, which can be implemented in any emergency department or doctor's practice. It provides quality assurance for the patient and promotes confidence in the attending physician.

Tibiofibular syndesmosis in acute ankle fractures: additional value of an oblique MR image plane

OBJECTIVE

To evaluate the additional value of a 45° oblique MRI scan plane for assessing the anterior and posterior distal tibiofibular syndesmotic ligaments in patients with an acute ankle fracture.

MATERIALS AND METHODS

Prospectively, data were collected for 44 consecutive patients with an acute ankle fracture who underwent a radiograph (AP, lateral, and mortise view) as well as an MRI in both the standard three orthogonal planes and in an additional 45° oblique plane. The fractures on the radiographs were classified according to Lauge-Hansen (LH). The anterior (ATIFL) and posterior (PTIFL) distal tibiofibular ligaments, as well as the presence of a bony avulsion in both the axial and oblique planes was evaluated on MRI. MRI findings regarding syndesmotic injury in the axial and oblique planes were compared to syndesmotic injury predicted by LH. Kappa and the agreement score were calculated to determine the interobserver agreement. The Wilcoxon signed rank test and McNemar's test were used to compare the two scan planes.

RESULTS

The interobserver agreement (κ) and agreement score [AS (%)] regarding injury of the ATIFL and PTIFL and the presence of a fibular or tibial avulsion fracture were good to excellent in both the axial and oblique image planes (κ 0.61-0.92, AS 84-95%). For both ligaments the oblique image plane indicated significantly less injury than the axial plane (p < 0.001). There was no significant difference in detection of an avulsion fracture in the axial or oblique plane, neither anteriorly (p = 0.50) nor posteriorly (p = 1.00). With syndesmotic injury as predicted by LH as comparison, the specificity in the oblique MR plane increased for both anterior (to 86% from 7%) and posterior (to 86% from 48%) syndesmotic injury when compared to the axial plane.

CONCLUSION

Our results show the additional value of an 45° oblique MR image plane for detection of injury of the anterior and posterior distal tibiofibular syndesmoses in acute ankle fractures. Findings of syndesmotic injury in the oblique MRI plane were closer to the diagnosis as assumed by the Lauge-Hansen classification than in the axial plane. With more accurate information, the surgeon can better decide when to stabilize syndesmotic injury in acute ankle fractures.

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.

Chronic instability of the anterior tibiofibular syndesmosis of the ankle. Arthroscopic findings and results of anatomical reconstruction

BACKGROUND

The arthroscopic findings in patients with chronic anterior syndesmotic instability that need reconstructive surgery have never been described extensively.

METHODS

In 12 patients the clinical suspicion of chronic instability of the syndesmosis was confirmed during arthroscopy of the ankle. All findings during the arthroscopy were scored. Anatomical reconstruction of the anterior tibiofibular syndesmosis was performed in all patients. The AOFAS score was assessed to evaluate the result of the reconstruction. At an average of 43 months after the reconstruction all patients were seen for follow-up.

RESULTS

The syndesmosis being easily accessible for the 3 mm transverse end of probe which could be rotated around its longitudinal axis in all cases during arthroscopy of the ankle joint, confirmed the diagnosis. Cartilage damage was seen in 8 ankles, of which in 7 patients the damage was situated at the medial side of the ankle joint. The intraarticular part of anterior tibiofibular ligament was visibly damaged in 5 patients. Synovitis was seen in all but one ankle joint. After surgical reconstruction the AOFAS score improved from an average of 72 pre-operatively to 92 post-operatively.

CONCLUSIONS

To confirm the clinical suspicion, the final diagnosis of chronic instability of the anterior syndesmosis can be made during arthroscopy of the ankle. Cartilage damage to the medial side of the tibiotalar joint is often seen and might be the result of syndesmotic instability. Good results are achieved by anatomic reconstruction of the anterior syndesmosis, and all patients in this study would undergo the surgery again if necessary.

Diagnosing syndesmotic instability in ankle fractures

The precise diagnosis of distal tibiofibular syndesmotic ligament injury is challenging and a distinction should be made between syndesmotic ligament disruption and real syndesmotic instability. This article summarizes the available evidence in the light of the author’s opinion. Pre-operative radiographic assessment, standard radiographs, computed tomography scanning and magnetic resonance imaging are of limited value in detecting syndesmotic instability in acute ankle fractures but can be helpful in planning. Intra-operative stress testing, in the sagittal, coronal or exorotation direction, is more reliable in the diagnosis of syndesmotic instability of rotational ankle fractures. The Hook or Cotton test is more reliable than the exorotation stress test. The lateral view is more reliable than the AP mortise view because of the larger displacement in this direction. When the Hook test is used the force should be applied in the sagittal direction. A force of 100 N applied to the fibula seems to be appropriate. In the case of an unstable joint requiring syndesmotic stabilisation, the tibiofibular clear space would exceed 5 mm on the lateral stress test. When the surgeon is able to perform an ankle arthroscopy this technique is useful to detect syndesmotic injury and can guide anatomic reduction of the syndesmosis. Many guidelines formulated in this article are based on biomechanical and cadaveric studies and clinical correlation has to be established.

Evaluation and management of ankle syndesmosis injuries

BACKGROUND

Ankle injuries are common in sporting activities with damage to the inferior tibiofibular ligaments being notable for their resultant disability and prolonged recovery.

OBJECTIVE

To provide a synopsis of the current best evidence regarding the recognition and treatment of injury to the syndesmotic ligaments of the ankle.

DESIGN

Structured narrative overview.

METHODS

Keyword search of Medline, CINAHL, and PEDro databases for studies published in English from January 1985 to July 2010. In addition, the reference lists from articles obtained were manually searched for relevant literature.

SUMMARY

This manuscript provides an overview of the distal tibiofibular pathologies, discusses the accuracy, limitations, and prognostic ability of clinical and radiographic examination techniques, and presents a philosophical approach to the rehabilitative management of syndesmotic injuries that integrates known biomechanical influences.

CONCLUSION

An appreciation for the mechanism of injury and a careful examination can distinguish these injuries from other forms of ankle instability. Proper recognition and immediate attention to the unique complexities of this joint can minimize morbidity and prevent a delayed return to sports.

Management of chronic disruption of the distal tibiofibular syndesmosis

Disruption of the distal tibiofibular syndesmosis is frequently accompanied by rotational ankle fracture such as pronation-external rotation and rarely occurs without ankle fracture. In such injury, not only inadequately treated or misdiagnosed cases, but also correctly diagnosed cases can possibly result in a chronic pattern which is more troublesome to treat than an acute pattern. This paper reviews anatomical and biomechanical characteristics of the distal tibiofibular joint, the mechanism of chronic disruption of the distal tibiofibular syndesmosis, radiological and arthroscopic diagnosis, and surgical treatment.

The additional value of an oblique image plane for MRI of the anterior and posterior distal tibiofibular syndesmosis

OBJECTIVE

The optimal MRI scan planes of collateral ligaments of the ankle have been described extensively, with the exception of the syndesmotic ligaments. We assessed the optimal scan plane for depicting the distal tibiofibular syndesmosis.

MATERIALS AND METHODS

In order to determine the optimal oblique caudal-cranial and lateral-medial MRI scan plane, two fresh frozen cadaveric ankles were used. The angle of the scan plane that demonstrated the anterior and posterior distal tibiofibular ligament uninterrupted in their full length was determined. In a prospective study this oblique scan plane was then used in addition to the axial and coronal planes, for MRI scans of both ankles in 21 healthy volunteers. Two observers independently evaluated the anterior tibiofibular ligament (ATIFL) and posterior tibiofibular ligament (PTIFL) regarding the continuity of the individual fascicles, thickness and wavy contour of the ligaments in both the axial and the oblique plane. Kappa was calculated to determine the interobserver agreement. McNemar's test was used to statistically quantify the significance of the two scan planes.

RESULTS

In the axial plane the ATIFL was in 31% (13/42) partly and in 69% (29/42) completely discontinuous; in the oblique plane the ATIFL was continuous in 88% (37/42) and partly discontinuous in 12% (5/42). Compared with the axial plane, the oblique plane demonstrated significantly less discontinuity (p<0.001), but not significantly less thickening (p=1.00) or less wavy contour (p=0.06) of the ATIFL. In the axial scan plane the PTIFL was continuous in 76% (32/42), partially discontinuous in 19% (8/42) and completely discontinuous in 5% (2/42); in the oblique plane the PTIFL was continuous in 100% (42/42). Compared with the axial plane, the oblique plane demonstrated significantly less discontinuity (p=0.002), but not significantly less thickening (p=1.00) or less wavy contour (p=0.50) of the PTIFL. The interobserver agreement score and kappa (κ) regarding the continuity for the ATIFL in the axial and oblique planes was 91% (κ=0.79) and 91% (κ=0.55) respectively; for the PTIFL it was 86% (κ=0.65) and 100% (κ = not defined).

CONCLUSION

The ATIFL and PTIFL are routinuely scanned in the orthogonal planes. The advantage of MRI scanning in an oblique image plane of about 45 degrees permits a better evaluation of the ligaments compared with the axial plane, particularly a better interpretation of ligament continuity, thickening and wavy contour. This may lead to a reduction in false-positive results, especially regarding partial or complete ligament ruptures. This can be of considerable aid in therapeutic management.

[Fractures of the upper ankle]

Upper ankle injuries are the most common reason for presentation in emergency departments. The initial treatment is often left in the hands of young clinical professionals. While the mechanism of injury might appear banal, insufficient diagnosis and treatment can lead to long periods of disability and functional impairment of the joint. Therefore, it is the aim of this work to provide a thorough understanding of the anatomy, biomechanics, mechanism of injury, diagnostic and operative procedures of ankle joint fractures.

Ankle sprains and fractures in adults

The orthopaedic nurse will undoubtedly care for patients with ankle injuries. Ankle sprains and fractures are common injuries seen in orthopaedic practices in the United States. To provide comprehensive nursing care of these injuries, nurses should understand ankle biomechanics as well as anatomy. Knowledge of fracture classification schemes, pathology of injury, and treatment modalities is also important. Fracture classification schemes vary as do treatment modalities. Ankle sprains and fractures can be treated operatively or nonoperatively, and orthopaedic nurses play an important role in the care of patients with such ankle injuries.

Management of ankle syndesmosis injuries in the athlete

Syndesmotic injuries or high ankle sprains in athletes can occur in elite and recreational athletes. They typically require a longer recovery and a significant delay in return to play compared with routine ankle sprains. Avoiding a misdiagnosis is important and is dependent on being aware of the mechanism of injury, a thorough physical examination, and careful interpretation of imaging studies. Management is guided by the severity of injury and the demands of the athlete. Many mild or stable injuries can be treated nonoperatively; however, acute surgical repair or stabilization in high-grade injuries can provide excellent results and an earlier return to play in selected cases.

Comparison of two intraoperative assessment methods for injuries to the ankle syndesmosis. A cadaveric study

BACKGROUND

Intraoperative stress testing is required for the detection of syndesmosis instability following an ankle fracture. The present study compared two stress tests for the detection of syndesmotic injury.

METHODS

A true mortise radiograph of the ankle was made for fourteen cadaver joints. Specimens were randomized into two groups to simulate ligament and syndesmosis injury on the basis of the Danis-Weber classification system. In the first group, the anterior inferior tibiofibular ligament was divided first (Weber B(r)), followed sequentially by division of the interosseous membrane (Weber C) and the deltoid ligament. In the second group, the deltoid ligament was divided first, followed by the anterior inferior tibiofibular ligament. Radiographs were made at each stage with use of two methods of stressing the ankle mortise: (1) external rotation of the foot with an external moment of 7.5 Nm, and (2) application of a lateral force of 100 N. Tibiofibular overlap, tibiofibular clear space, and medial clear space were measured.

RESULTS

Lateral stress produced a significantly greater increase in the tibiofibular clear space than did the external rotation test for Weber C injuries and Weber C plus deltoid ligament injuries. A greater increase in the tibiofibular clear space was noted during the lateral stress test when both the deltoid and the anterior inferior tibiofibular ligament had been sectioned (p < 0.05). The external rotation stress test produced a significant increase in the medial clear space in the presence of isolated anterior inferior tibiofibular ligament and deltoid ligament injuries (p < 0.05).

CONCLUSIONS

For the detection of syndesmotic instability at the site of ankle fractures on stress radiographs, the lateral stress test appeared to be superior to the external rotation stress test in this cadaver model.

Delayed operative treatment of syndesmotic instability. Current concepts review

OBJECTIVE

To review the literature concerning articles evaluating the delayed operative treatment of isolated syndesmotic instability.

MATERIAL AND METHODS

The main databases Pubmed/Medline, Cochrane Database of Systematic Reviews, Cochrane Clinical Trial Register, Current Controlled Trials and Embase were searched from 1988 to September 2008 to identify studies relating to the late reconstruction of the distal tibiofibular syndesmosis after isolated syndesmotic injury. The level of evidence of the included articles was scored.

RESULTS

Fifteen articles were identified, involving 94 ankles with a delayed reconstruction for isolated syndesmotic instability.

CONCLUSION

In subacute (6 weeks to 6 months) total ruptures the focus is to restore the normal anatomy by repair of the ruptured ligament with placement of a syndesmotic screw. On base of the literature in combination with experience in clinical practice some guidelines are formulated. If inadequate remnants of the anterior inferior tibiofibular ligament (AITFL) are present, a tendon graft can be used. The insertion of the AITFL on the tibia can be medialised with a bone block and fixed with a screw. For the treatment of persistent widening and late instability these reconstruction techniques have to be used combined with debridement and placement of a syndesmotic screw to protect the reconstruction. Most adequate treatment for chronic syndesmotic instability (>6 months) is the creation of a synostosis to stabilise the distal tibiofibular joint. Late repairs give satisfactory but less favourable outcome as compared to properly treated acute injuries. It is not easy to regain complete stability by means of these secondary procedures.

A dynamic ultrasound examination for the diagnosis of ankle syndesmotic injury in professional athletes: a preliminary study

BACKGROUND

Syndesmotic ankle injuries are not easy to recognize when an associated fracture or frank diastasis is not present. There is a need for a simple, fast, inexpensive, and easily reproducible diagnostic tool to assess the integrity of the distal tibiofibular synedesmosis.

HYPOTHESIS

Dynamic ultrasound (US) examination can accurately diagnose anteroinferior tibiofibular ligament (AITFL) rupture.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

We evaluated 3 groups: 9 consecutive professional athletes with recent AITFL rupture, a control group of 18 subjects without a history of ankle injury, and 20 patients with lateral ankle sprain. The dynamic US examination was performed in neutral (N), forced internal rotation (IR), and external rotation (ER) of the foot for measuring the tibiofibular clear space on the anterior aspect of the ankle, at the level of the AITFL, 1 cm proximal to the joint line.

RESULTS

The mean age of the study group was 27 years (range, 16-32). Magnetic resonance imaging (MRI) confirmed the diagnosis of AITFL rupture in all cases. Differences between the injured and control group were statistically significant for the N, IR, and ER positions (P < .001) and for the measured Delta between the AITFL in the ER and N positions (P < .01). The difference in the tibiofibular clear space between the 2 ankles of the injured athletes was significantly different compared with the control athletes for all 3 positions (P < .001). The measured difference between the ER and N positions for both sides of the study group showed a specificity and sensitivity of 100% (P < .001; cutoff point of 0.9 mm and 0.7 mm, respectively). The Delta (Delta = ER - N) of the injured side showed a specificity and sensitivity of only 89% (P < .001; cutoff point of 0.4 mm). Additionally, the third group with the history of lateral ankle sprain showed, as expected, that this type of injury does not correlate with AITFL injury on dynamic US examination.

CONCLUSION

We conclude that dynamic US examination can be used to accurately diagnose an AITFL rupture. This preliminary study has found the described method to be a simple, inexpensive, and easily reproducible examination.

MR arthrography of the ankle: indications and technique

MR arthrography has become an important tool for the assessment of a variety of ankle disorders. MR arthrography permits more sensitive imaging of suspected intra-articular pathology in cases in which conventional MR imaging is either insufficient or inadequate for diagnosis or treatment planning. The main indications for MR arthrography are the evaluation of ligamentous injuries, impingement syndromes, cartilage lesions, osteochondral lesions of the talus, loose bodies, and several synovial joint disorders. Indirect MR arthrography can be a useful adjunct to conventional MR imaging and may be preferable to direct MR arthrography in those cases in which an invasive procedure is contraindicated or image guidance is not available.

MRI of isolated distal fibular fractures with widened medial clear space on stressed radiographs: which ligaments are interrupted?

OBJECTIVE

Patient management choices in ankle fractures remain controversial because of ambiguities in assessing ankle stability and lack of information on the integrity of all supporting ligaments. Our objective was to use MRI to identify the range of ankle ligament injuries associated with a problematic subset of ankle fracture: isolated fibular fractures for which widened medial clear space is absent or minimal on standard ankle radiographs but evident on stress images.

CONCLUSION

In our retrospective study of 19 patients, we have categorized ligament injury and found partial or complete tears in all cases in at least two of the four major ligament groups--usually the deltoid and syndesmosis groups. The anterior inferior tibiofibular ligament of the syndesmosis suffered complete interruption in every case. The posterior tibiotalar ligament of the deltoid group, a major contributor to stability, was generally injured but, unexpectedly, most of these tears were partial.

Injuries to the tibiofibular syndesmosis

The management of injury to the distal tibiofibular syndesmosis remains controversial in the treatment of ankle fractures. Operative fixation usually involves the insertion of a metallic diastasis screw. There are a variety of options for the position and characterisation of the screw, the type of cortical fixation, and whether the screw should be removed prior to weight-bearing. This paper reviews the relevant anatomy, the clinical and radiological diagnosis and the mechanism of trauma and alternative methods of treatment for injuries to the syndesmosis.

Ankle syndesmotic injury

Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome.

Chronic tibiofibular syndesmosis injury of ankle: evaluation with contrast-enhanced fat-suppressed 3D fast spoiled gradient-recalled acquisition in the steady state MR imaging

PURPOSE

To retrospectively determine the accuracy of coronal contrast material-enhanced fat-suppressed three-dimensional (3D) fast spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging, as compared with that of routine transverse MR imaging, in the assessment of distal tibiofibular syndesmosis injury, with arthroscopy as the reference standard.

MATERIALS AND METHODS

The review board of the College of Medicine in Yonsei University approved this study; informed consent was waived. The study group comprised 45 patients (26 men, 19 women; mean age, 32.1 years; range, 18-58 years) with a chronic ankle injury who had undergone MR imaging and arthroscopic surgery. Three independent readers retrospectively reviewed the two sets of MR images (one set of gadolinium-enhanced 3D fast SPGR images and one set of routine T1-, T2-, and intermediate-weighted images). Scores from 1 to 5 in increasing order of the probability of injury were assigned to both sets. Arthroscopy was the reference standard. Syndesmotic recess height was measured on contrast-enhanced images. The two sets of images were compared for diagnostic performance with receiver operating characteristic (ROC) analysis. Dissection and histologic examination of six cadaveric ankles was performed to assess the syndesmotic area and ascertain the enhancing structure at MR imaging.

RESULTS

At arthroscopy, syndesmotic injury was found in 24 ankles but not in 21 ankles. Areas under the ROC curve were significantly higher for the contrast-enhanced images (P<.05). The contrast-enhanced set showed higher accuracy, sensitivity, and specificity compared with the routine set for the assessment of syndesmosis injury. Mean syndesmotic recess height was significantly greater (P<.05) in patients with syndesmotic injury. Dissection and histologic examination revealed a highly vascular synovial fold in the syndesmotic area that is expected to enhance at MR imaging.

CONCLUSION

In the assessment of chronic syndesmosis injury, coronal gadolinium-enhanced fat-suppressed 3D fast SPGR MR images were more sensitive, specific, and accurate than routine MR images.

Evidence-based approach to treatment of acute traumatic syndesmosis (high ankle) sprains

Ankle sprains in the athlete are one of the most common injuries, and syndesmosis or "high-ankle" sprains seem to being diagnosed at an increasing rate. As a result, there has been a heightened interest in recognizing and treating these difficult injuries on a timely basis, particularly in the athlete. Although the recognition and diagnosis of these injuries have improved, there still exists a paucity of information on optimal conservative and operative management. In this paper, a systematic review of the literature was conducted to provide an evidence-based rationale in the diagnosis and treatment of syndesmosis (high ankle) sprains in athletes. It is obvious from the low level of evidence available in the literature on this topic that a great deal of work is needed before conclusive statements regarding the management of these injuries can be made with confidence. The current diagnostic tests are not very specific. Because this is a spectrum of injury, there is a lot of variability in the time lost from sport. It is clear that we need a much more definitive diagnostic process for this injury that allows us to predict the severity of the injury, time loss from sport, and the treatment required.

Three-dimensional volume rendering of tibiofibular joint space and quantitative analysis of change in volume due to tibiofibular syndesmosis diastases

OBJECTIVE

The diagnosis of ankle syndesmosis injuries is made by various imaging techniques. The present study was undertaken to examine whether the three-dimensional reconstruction of axial CT images and calculation of the volume of tibiofibular joint space enhances the sensitivity of diastases diagnoses or not.

DESIGN

Six adult cadaveric ankle specimens were used for spiral CT-scan assessment of tibiofibular syndesmosis. After the specimens were dissected, external fixation was performed and diastases of 1, 2, and 3 mm was simulated by a precalibrated device. Helical CT scans were obtained with 1.0-mm slice thickness. The data was transferred to the computer software AcquariusNET. Then the contours of the tibiofibular syndesmosis joint space were outlined on each axial CT slice and the collection of these slices were stacked using the computer software AutoCAD 2005, according to the spatial arrangement and geometrical coordinates between each slice, to produce a three-dimensional reconstruction of the joint space. The area of each slice and the volume of the entire tibiofibular joint space were calculated. The tibiofibular joint space at the 10th-mm slice level was also measured on axial CT scan images at normal, 1, 2 and 3-mm joint space diastases.

RESULTS

The three-dimensional volume-rendering of the tibiofibular syndesmosis joint space from the spiral CT data demonstrated the shape of the joint space and has been found to be a sensitive method for calculating joint space volume. We found that, from normal to 1 mm, a 1-mm diastasis increases approximately 43% of the joint space volume, while from 1 to 3 mm, there is about a 20% increase for each 1-mm increase.

CONCLUSIONS

Volume calculation using this method can be performed in cases of syndesmotic instability after ankle injuries and for preoperative and postoperative evaluation of the integrity of the tibiofibular syndesmosis.

Diagnosis and imaging of ankle instability

Ankle instability is a major cause of symptoms following an ankle sprain. With a thorough history and examination, appropriate additional investigations, including cross-sectional imaging, and thoughtful interpretation of the information, one should rarely be caught out by misdiagnosis, multiple diagnoses, or unusual causes.

Acute and chronic syndesmosis injuries: pathomechanisms, diagnosis and management

Both acute and chronic syndesmotic injuries can lead to significant morbidity. The key to management of acute injuries is anatomic reduction of the fibula and the syndesmosis. A high index of suspicion for syndesmotic injuries will allow the surgeon to avoid the difficult reconstruction options for chronic diastasis.

Fixation of posterior malleolar fractures provides greater syndesmotic stability

Syndesmotic injuries are common in ankle fractures. Traditional syndesmosis fixation may be associated with a secondary procedure. When the posterior malleolus is fractured, the posterior syndesmotic ligaments may remain intact and attached to the fragment. Our goals were to establish the incidence of syndesmotic ligament ruptures in pronation-external rotation type ankle injuries associated with posterior malleolar fractures, and to assess syndesmotic stability after fixation of the posterior malleolus compared with using a syndesmotic screw. Fifteen patients who sustained pronation-external rotation Stage 4 ankle fractures that involved the posterior malleolus were evaluated using radiographs and magnetic resonance imaging. No complete tears of the posterior-inferior tibiofibular ligament occurred. A pronation-external rotation fracture pattern with a posterior malleolar fragment was created in 10 lower extremity cadaver specimens with random fixation of the posterior malleolus or the syndesmosis. Compared with the intact specimens, stiffness was restored to 70% after fixation of the posterior malleolus, and to 40% after syndesmosis stabilization. Syndesmotic stability may be obtained more effectively by fixation of the posterior malleolus rather than by using a syndesmotic screw. Although additional clinical investigation is warranted, these concepts may be useful in eliminating syndesmotic screw fixation in select patients.

Ankle syndesmosis injuries: anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention

Syndesmosis injuries are rare, but very debilitating and frequently misdiagnosed. The purpose of this clinical commentary is to review the mechanisms of syndesmotic injuries, clinical examination methods, diagnosis, and management of the injuries. Cadaveric studies of the syndesmosis and deltoid ligaments are also reviewed for further understanding of stress transmission and the roles of different structures in stabilizing the distal syndesmosis. External rotation and excessive dorsiflexion of the foot on the leg have been reported as the most common mechanisms of injury. The injury is most often incurred by individuals who participate in skiing, football, soccer, and other sport activities played on turf. The external rotation and squeeze tests are reliable tests to detect this injury. The ability of imaging studies to assist in an accurate diagnosis may depend on the severity of the injury. The results of cadaveric studies indicate the importance of the deltoid ligament in maintaining stability of the distal tibiofibular syndesmosis and the congruency of the ankle mortise. Intervention programs with early rigid immobilization and pain relief strategies, followed by strengthening and balance training are recommended. Heel lift and posterior splint intervention can be used to avoid separation of the distal syndesmosis induced by excessive dorsiflexion of the ankle joint. Application of a rigid external device should be used with caution to prevent medial-lateral compression of the leg superior to the ankle mortise, thereby inducing separation of the distal syndesmosis articulation. Surgical intervention is an option when a complete tear of the syndesmotic ligaments is present or when fractures are observed.

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.

Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments

The aim of this study was to describe the detailed anatomical arrangement of ligaments of the tibiofibular syndesmosis and to highlight the clinical aspects of fracture dislocations. This study was performed on 42 legs of adult human embalmed cadavers. Tibiofibular syndesmosis ligaments attachments and their mutual relationships were described and their dimensions were measured. The anterior tibiofibular ligament is usually composed of three parts. This ligament runs obliquely at laterodistaly direction making 35 degrees angle with horizontal plane and posteriorly 65 degrees angle with sagittal plane. The posterior tibiofibular ligament runs almost horizontally 20 degrees angle with horizontal plane. The mean thicknesses of tibial and fibular attachments are 6.38+/-1.91 mm and 9.67+/-1.74 mm, respectively. The inferior transverse ligament originates from just below the posterior tibiofibular ligament, which has variations on the shape and dimensions due to its attachment points. The average length is 36.60+/-9.51 mm. The network between the fibular notch and the distal fibula has been filled with the interosseous tibiofibular ligament whose fibers follow the laterodistal and anterior direction from the tibia to the fibula. It lies proximally 30-40 mm from the mortise. At the inferior view of the tibiofibular syndesmosis a pyramidal shaped cartilaginous facet was observed which was attached to the fibula. The length of this cartilage was variable. Some of synovial plicas from the ankle joints synovial membrane were observed at this view. We conclude that the results of this study may be useful to both orthopedic surgeons and radiologists for anatomic evaluation of the tibiofibular syndesmosis area.

3T MR Imaging of the Musculoskeletal System (Part II): Clinical Applications

The gain in SNR that is afforded by 3T MR imaging systems has tremendous clinical applications in the musculoskeletal system. The potential for demonstrating and enhancing the visibility of normal osseous, tendinous, cartilaginous, and ligamentous structures is exciting. Furthermore, harnessing this added signal to increase spatial resolution may improve our diagnostic abilities in various joints dramatically. Radiologists have enjoyed great success in assessing joint disease with current MR imaging field strengths; however, many intrinsic joint structures remain poorly evaluated, which leads to a golden opportunity for 3T MR imaging. The articular cartilage of the knee, the glenoid labrum of the shoulder, the intrinsic ligaments and TFC of the wrist, the collateral ligaments of the elbow, the labrum and articular cartilage of the hip, and the collateral ligaments of the ankle have been evaluated suboptimally on 1 .5T systems using routine nonarthrographic MR images. Because of the enhanced SNR, the higher spatial resolution, and the greater CNR of intrinsic joint structures at higher field strengths, 3T MR imaging has the potential to improve diagnostic abilities in the musculoskeletal system vastly, which translates into better patient care and management. The author's 2 years of clinical experience with musculoskeletal MR imaging on 3T systems has met and exceeded his expectations, and has bolstered the confidence of his orthopedic surgeons in his diagnoses. As coil technology advances and as the use of parallel imaging becomes more available in the extremities, the author expects to see even more dramatic improvements in image quality.

Radiographic measurements do not predict syndesmotic injury in ankle fractures: an MRI study

Several radiographic measurements have been described and are used to determine ligamentous injury in ankle fractures, particularly of the deltoid and syndesmosis complex. Because the accuracy of these radiographic measurements has been questioned, we sought to evaluate their accuracy using magnetic resonance imaging as an indicator for injury. Seventy patients with closed ankle fractures were entered prospectively into the study, and all had standard plain radiographic evaluations before reduction (anteroposterior, lateral, and mortise) and magnetic resonance imaging. Four radiographic measurements were made on initial ankle injury films: tibiofibular clear space on the anteroposterior view, tibiofibular overlap on the anteroposterior and mortise views, and medial clear space on the mortise view. These radiographic measurements and their association with magnetic resonance imaging findings then were analyzed. A medial clear space measurement greater than 4 mm correlated with disruption of the deltoid and the tibiofibular ligaments. We found no association between the tibiofibular clear space and overlap measurements on radiographs with syndesmotic injury on magnetic resonance imaging scans.

LEVEL OF EVIDENCE

Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.