Imaging of the acetabulum in the era of multidetector computed tomography

Acetabular fractures are often complex injuries and the result of high-energy trauma with associated injuries. Understanding and classification of these rare injuries using radiography can be difficult and are much facilitated by the addition of computed tomography (CT). The purpose of this paper is to briefly review some of the underlying physical principles and technical factors for multidetector CT (MDCT) and to describe its use and imaging findings in the evaluation of acetabular fractures. Using MDCT with two-dimensional multiplanar reformatted (MPR) images and three-dimensional volume rendered images, the supplemental oblique radiographic Judet views can be omitted. MDCT is now an indispensable tool in preoperative imaging of acetabular fractures and also in postoperative imaging in complicated cases. Not only is MDCT excellent for a general overview but also for detailed imaging of fracture extent, joint congruency, step-offs or gaps in the joint surface, and entrapped osteochondral fragments.     

Ankle fractures: Understanding the mechanism of injury is the key to analyzing the radiographs

Injuries to the ankle joint are common. Complete ligament ruptures and fractures of the malleoli and adjacent bones can affect the stability of the ankle joint. If fractures or ligament injuries are present on both sides of the joint, the ankle will usually be unstable. On the other hand, injuries confined to one side of the joint will usually be stable. Unstable ankle joints require operative fixation, whereas stable ankles do well with conservative treatment. Specific ligament injuries precede several fractures. Recognition of the various patterns of injury permits reliable prediction of these ligament injuries. Therefore, it is important for radiologists and others who interpret trauma radiographs to understand the common mechanisms of injury and to recognize these patterns. Correct classification of the injury mechanism should lead to prompt, appropriate diagnosis and treatment and should decrease long-term morbidity.     

Acute knee injuries

Skeletally immature athletes do get major knee injuries. Hemarthrosis is associated with peripheral meniscal tears, anterior cruciate ligament ruptures, tibial tubercle avulsion injuries, and patellar/femoral osteochondral fractures and cannot be ignored. The primary diagnostic tool for patients with a knee injury is a clinical examination by a physician well trained in knee evaluation. MR imaging has significant limitations in this age group. The algorithm for anterior cruciate ligament injury treatment must take into account the patient's physiologic maturity, not chronological age.     

Traumatology of the knee joint--radiologic and accident surgery aspects--1

Lesions of the knee joint are relatively frequent and are on the increase due to the increasing number of sports and traffic accidents. Violent force exercised on the knee can lead basically to two different kinds of injury sequels. As a rule, injuries to the bone do not present diagnostic problems if there is a clear break in continuity. On the other hand, it is often very difficult to detect chondral or osteochondral lesions and also certain types of longitudinal patellar fractures and fractures of the head of the tibia. Their visualisation requires more far-reaching diagnostic measures. Fundamentally more difficult to identify: the second group of lesions, namely, those of the internal structures of the knee, unless there is a marked instability which is usually accessible to clinical examination. Relatively slight osseous tears or ruptures of a ligament often remain unnoticed on the plain x-ray film. Other diagnostic techniques are imperative in such cases. The first part deals specifically with the radiological aspects of knee injuries. The majority of injuries close to the knee region can be visualized by making use of all techniques of roentgenology. However, if the examination methods get too costly and complicated without ensuring an absolutely safe diagnosis, other techniques must be employed. An example in this regard are the chondral or osteochondral lesions. It is here that arthroscopy often yields better results while offering at the same time a possibility to remove individual small fragments.     

膝关节韧带损伤与胫骨平台骨折Schatzker及AO分型的相关性分析

目的分析膝关节韧带损伤与胫骨平台骨折Schatzker分型及AO分型的相关性。方法选取2018年1月至2019年6月厦门大学附属福州第二医院骨科收治的28例胫骨平台骨折合并膝关节韧带损伤患者作为研究对象,根据Schatzker分型及AO分型系统对胫骨平台骨折进行分型,同时判定前交叉韧带(anterior cruciate ligament,ACL)、后交叉韧带(posterior cruciate ligament,PCL)、内侧副韧带(medial collateral ligament,MCL)及后外侧角(posterior lateral corner,PLC)的损伤情况,并采用Spearman相关系数分析膝关节韧带损伤与胫骨平台骨折Schatzker分型及AO分型的相关性。结果Schatzker分型与AO分型(仅以关节外、部分关节内和完全关节内3种类型计算)对应分析结果显示,两者具有显著相关性(P=0.000)。Schatzker分型及AO分型与韧带损伤类型Spearman相关分析结果显示,Schatzker分型及AO分型与ACL、MCL及PLC损伤均呈显著相关性(r=-0.465、-0.639、0.756,P=0.013、0.000、0.000;r=-0.588、-0.420、0.532,P=0.001、0.026、0.004),但若AO分型以关节外、部分关节内和完全关节内3种类型计算,则仅与ACL损伤呈显著相关性(r=-0.465,P=0.013)。结论膝关节损伤时膝关节相关韧带之间有一定协同作用,故胫骨平台骨折多合并膝关节韧带损伤,且随着Schatzker分型与AO分型等级的增高,ACL、MCL及PLC损伤的可能性均增大。     

Delayed surgical treatment for tibial avulsion fracture of the posterior cruciate ligament in children

Avulsion fractures of the posterior cruciate ligament (PCL) at the tibial insertion site are extremely rare in children. Because the avulsed osteochondral fragments can be poorly seen on plain radiographs, correct diagnosis is often delayed. Delayed diagnosis of PCL avulsion fracture can lead to difficulties in treatment due to secondary changes in the osteochondral fragment and ligament substance. Three cases of tibial avulsion fractures of the PCL in children surgically treated in a single medical centre are reported in the present study. Level of evidence V.     

Acute osteochondral injuries of the hip

Acute osteochondral injuries of the hip are rare in the absence of associated dislocation. A series of cases is presented in which these injuries were sustained after relatively minor trauma to the hip. Radiologic studies revealed evidence of mild hip dysplasia and, in one case, an osteochondral fracture of the right femoral head. Scintigraphy revealed the fracture and unexpected uptake in the acetabulum, which was subsequently confirmed as being due to labral tears or acetabular osteochondral injuries. In addition, the scan showed evidence of a possible avulsion-type injury of the iliofemoral ligament, suggesting the mechanism of subluxation.     

Akutes Trauma des Sprunggelenks

The diagnosis of lateral collateral ankle ligament trauma is based on patient history, clinical examination, and clinical stress tests. If the clinical stress test is positive, stress radiography could be performed. There is no consensus about the usefulness of stress radiography in acute ankle sprain, particularly about the cut-off talar tilt angle beyond which a two-ligament rupture would be certain, ranging from 5 degrees to 30 degrees. Today MRI is not used for this indication, although it allows, with controlled positioning of the foot and with defined sections, visualization of injured lateral collateral ankle ligaments. In ankle injuries, plain radiographs form the established basis of diagnostic imaging and can provide definitive answers in most cases. CT is used in complex fractures for complete visualization. MRI is the method of choice for several diagnostic problem cases, including occult fractures and post-traumatic avascular necrosis. In tendon injuries, MRI is important if ultrasound is not diagnostic. Generally, for the evaluation of acute ankle injuries, MRI is the most important second-step procedure when radiographs are nondiagnostic.     

The accuracy of three-dimensional magnetic resonance imaging in the diagnosis of ruptures of the lateral ligaments of the ankle.

In a prospective study, the diagnostic accuracy of three-dimensional magnetic resonance imaging in the evaluation of ruptures of the lateral ligaments of the ankle was determined by comparing three-dimensional magnetic resonance findings with operative findings. In a series of 18 consecutive cases of acute significant inversion trauma to the ankle, a three-dimensional fast imaging with steady-state precession pulse sequence (3D FISP) was performed. The study included only those cases in which views showed a difference in talar tilt of 15 degrees or more, and a difference in anteroposterior drawer of 10 mm or more between the imaged and the normal ankle. All ankles were scheduled for surgical exploration. Compared with operative findings, the sensitivity, specificity, and accuracy of 3D FISP imaging were, respectively, 100%, 50%, and 94.4% for ruptures of the anterior talofibular ligament and 91.7%, 100%, and 94.4% for ruptures of the calcaneofibular ligament. We believe that 3D FISP magnetic resonance imaging is a noninvasive, fast, and very accurate diagnostic aid to operative planning for double ligament tears in younger competitive athletes.     

Injuries of the lateral ankle ligaments: classification with tenography and arthrography

To assess the value of tenography of the peroneal tendon sheaths and of arthrography of the tibiotalar joint for the diagnosis and classification of recent ruptures of the lateral ankle ligaments, the authors performed a prospective study on 108 patients with inversion trauma of the ankle. All patients underwent tenography. Arthrography was performed if results of tenography were negative. All patients with positive tenographic or arthrographic results underwent surgery. Tenography proved to be reliable in the diagnosis of injuries of the calcaneofibular ligament (sensitivity, 88%; specificity, 87%-94%). The positive predictive value of tenography in combination with arthrography was 100% for the diagnosis of lateral ligament ruptures. The authors conclude that a combination of arthrography and tenography is a reliable method for diagnosing recent ruptures of the lateral ankle ligaments and for differentiating between isolated ruptures of the talofibular ligament and combined lesions of both the talofibular and the calcaneofibular ligaments.     

A computer assisted surgical technique for retrograde autologous osteochondral grafting in talar osteochondritis dissecans (OCD): a cadaveric study

This study describes a new method for the treatment of osteochondritis dissecans (OCD) in the medial talar dome. Ten cadaveric lower extremities were used to develop and evaluate a retrograde osteochondral grafting technique applying computer-assisted surgery. With the help of a computed tomography (CT)-based navigation system, a guide wire was placed from the lateral talar process into the posteromedial talar trochlea where OCD lesions are predominantly located. Cannulated reamers and arthroscopic shavers were used for the preparation of the recipient hole. The grafts, with diameters of 4.5 mm, 6.5 mm or 8.5 mm were harvested from the lateral femoral trochlea and inserted in a retrograde fashion. The last five cadavers were analyzed for accuracy of surface reconstruction and graft stability. For this purpose a medial malleolar osteotomy and a CT scan was performed. We found steps in the joint surface to range from 0.5 mm to 1.5 mm (mean 0.9 mm, SD 0.4) with the graft always below the surrounding cartilage. Graft subsidence occurred at an applied force of 26.4 +/- 4.6 N. This study indicates that osteochondral cylinders can be inserted in a retrograde fashion to reconstruct the posteromedial talus. Good surface congruency and sufficient graft stability can be achieved.     

The biomechanical influence of tibio-talar containment on stability of the ankle joint

Chronic ankle instability (CAI) is a frequent sport orthopaedic entity. Although many risk factors have been studied extensively, little is known how it is influenced by the osseous joint configuration. Based on lateral X-rays, the radius of the talar surface and the tibial coverage of the talus (sector alpha) were measured on a DICOM/PACS system in 52 patients with CAI and an age- and sex-matched control group. The talar radius was found to be larger in patients with CAI (21.2 +/- 2.4 mm) than in the control group (17.7 +/- 1.9 mm; P < 0.0001). The tibio-talar sector was smaller in patients with CAI (80 degrees +/- 5.1 degrees ) than in the control group (88.4 degrees +/- 7.2 degrees ; P < 0.0001). The aim of this study is to analyse the biomechanical influence of the clinical data on stability of the ankle joint. A two-dimensional model of the tibio-talar joint in the sagittal plane was developed. The joint configuration was described by the tibio-talar sector (alpha) and the radius (r) of the talus. The force (F = F (BW) tan alpha/2) and energy (E = F (BW) r [1 - cos alpha/2]) to dislocate the talus out of the tibial plafond were deduced. Ankle stability is a function of the tibio-talar sector: the force necessary to dislocate the joint is decreasing with a smaller sector. The clinical data show that the force needed to dislocate the ankle of CAI patients was 14% weaker than the one needed in the case of healthy subjects (P < 0.0001). The energy to dislocate the ankle depends both on the sector and the radius. The clinical data do not show a significant difference between the energy needed to dislocate the joint of CAI patients and the one of healthy subjects. This is because there is a correlation of a small sector and a large radius for CAI ankles. CAI is associated with an unstable osseous joint configuration, which is characterized by a larger radius of the talus and a smaller tibio-talar sector. The findings of the biomechanical model explain the clinical observations and demonstrate how stability of the ankle joint is influenced by the osseous configuration. Surgical ankle ligament stabilization might be more recommended in patients with an unstable osseous configuration as such patients have a disposition for recurrent sprains. Removing anterior osteophytes for anterior impingement should be done carefully in CAI patients because this would decrease the tibial coverage of the talus and thus dispose the talus to dislocate anteriorly. People who have an unstable ankle configuration and who nevertheless engage in activities with high risk of ankle sprains could be asked to wear ankle protecting sports equipment.     

Acute paediatric ankle trauma: MRI versus plain radiography

OBJECTIVE: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. METHODS: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three "masked" radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. RESULTS: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures, Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter-Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. CONCLUSIONS: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries.     

Detection of occult fractures of the pelvic bones by roentgen computed tomography

The informational value of C.T. concerning pelvic fractures is presented. Not all injuries to the hip joint and to the os sacrum can be seen on standard a.p.-projections, oblique views, special projections or conventional tomography. 17 typical examples have been selected from young patients with multiple injuries. C.T.-findings concerning fractures of the hip joint, of the os sacrum and of hidden pelvic fractures are described. Emphasis is placed on careful radiological analysis of fractures with special regard to the planning of conservative or operative treatment and also on the later functional results following fractures of the hip joint.     

Traumatic injuries: imaging of spinal injuries

Severe (high-energy) spinal injuries are common sequelae of acute traumas. The task of radiology is to establish the radiological diagnosis, classify it, judge stability and instability and lead further radiological evaluation in cases of non-agreement between the radiological diagnosis and the clinical (neurological) findings. While skeletal abnormalities are best diagnosed with spiral CT and to a lesser degree with plain-film radiographs, soft tissue lesions, such as cord injuries or ligament ruptures, are best outlined with emergency MRI. The classification of fractures depends on fracture (trauma)-biomechanics and location. All these efforts are necessary to get the best clinical outcome for the patient.     

Wrist Trauma: More Than Bones

Acute and subacute wrist trauma predominantly consist of fractures of the distal radius in elderly patients and most frequently carpal fractures (scaphoid, followed by triquetrum and hamatum) and avulsion fractures of the ulnar styloid in younger patients, especially in sports-related injuries but also in work activities. The initial radiographs may miss the fractures and result when untreated in complications as nonunion, osteonecrosis, and degenerative osteoarthritis.Fractures of the distal radius and of the scaphoid may be associated with ligament injuries, most frequently the scapholunate complex, which are often overlooked at the emergency department. Patients without osseous injuries may present intrinsic and extrinsic ligament tears that may lead to carpal instability when they are clinically and/or radiologically missed.Therefore, in acute and subacute setting, computed tomography may be helpful for the detection of subtle fractures, and magnetic resonance imaging, for the early diagnosis of occult fractures and ligament injuries.     

The radiological functional testing in fibular ligament lesions--a critical analysis and clinical study

Injuries to the lateral ligaments of the ankle require an accurate diagnosis, especially because most injuries to one ligament are not treated surgically any more. Different stress devices are in use for an objective and standardised assessment of the instability of the ankle joint. In a group of 76 patients with injuries to their lateral ligaments of the ankle we compared posttraumatic instability by radiological stress test as done by hand or by a Telos stress device. In 25 patients treated by surgery an additional intraoperative stress X-ray (talar tilt) was performed. The results of the instability tests done by hand versus those obtained with a Telos stress device showed a poor correlation (r = 0.786). An analogous result was obtained by comparing the Telos device stress views to the intraoperative stress controls done by hand (r = 0.771). Only the pre- and intraoperative measurements by hand showed a good correlation (r = 0.958). The results are discussed with reference to a biomechanical model and recommendations for routine diagnosis are proposed.     

Arthroscopic assessment for intra-articular disorders in residual ankle disability after sprain

BACKGROUND: After ankle sprain, there can be many causes of disability, the origins of which cannot be determined using standard diagnostic tools. HYPOTHESIS: Ankle arthroscopy is a useful tool in identifying intra-articular disorders of the talocrural joint in cases of residual ankle disability after sprain. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: The authors gathered the independent diagnostic results of physical examination, standard mortise and lateral radiography, stress radiography of the talocrural joint, and magnetic resonance imaging for 72 patients with residual ankle disability lasting more than 2 months after injury (mean, 7 months after injury). They performed arthroscopic procedures and compared the double-blind results. RESULTS: In all cases, the arthroscopic results matched those of other means of diagnosis. In 14 cases, the arthroscopic approach exceeded the capabilities of the other methods. Including duplications, 39 patients (54.2%) had anterior talofibular ligament injuries, 17 patients (23.6%) had distal tibiofibular ligament injuries, 29 patients (40.3%) had osteochondral lesions, 13 patients (18%) had symptomatic os subfibulare, 3 patients (4.2%) had anterior impingement exostosis, and 3 patients (4.2%) had impingement due to abnormally fibrous bands. There were only 2 cases in which the cause of symptoms could not be detected by ankle arthroscopy, compared with 16 cases in which the cause of disability could not be detected using standard methods. In 3 cases (17.6%) of distal tibiofibular ligament injuries, 8 cases (27.6%) of osteochondral lesions, and all 3 cases (100%) of impingement of an abnormal fibrous band, ankle arthroscopy was the only method capable of diagnosing the cause of residual ankle pain after a sprain. CONCLUSION: The present results suggest that arthroscopy can be used to diagnose the cause of residual pain after an ankle sprain in most cases that are otherwise undiagnosable by clinical examination and imaging study.     

Wrist disorders in the young athlete

In the young athlete, forced dorsiflexion causes most wrist injuries. Sudden dorsiflexion from a fall onto theoutstretched hand results in fractures, ligament tears, and joint disruptions. Repetitive dorsiflexion, which occurs in activities such as weightlifting or gymnastics, leads to overuse injuries including physeal stress fractures, bone stress fractures, triangular fibrocartilage complex tears, impingement syndromes, progressive laxity and arthritic degeneration. Wrist braces have not been successful in preventing fractures. Wrist taping or bracing is inadequate to prevent wrist overuse injuries in gymnasts. Treatment of wrist injuries involves rest, splinting or casting, and both open and arthroscopic surgical techniques.     

Radiological evaluation of temporal bone disease: high-resolution computed tomography versus conventional X-ray diagnosis

Sixty-two patients with different temporal bone lesions were prospectively examined by high-resolution computed tomography (CT) and conventional plain radiography, including pluridirectional tomography. High-resolution CT enabled a clear diagnosis in 80% of cases, conventional radiology in 63%; 1.6-times more bone information was recorded by high-resolution CT which is clearly superior for imaging cholesteatomas, metastases and inflammatory processes and for evaluating osseous destruction. With regard to pathological soft tissue or effusions filling the tympanic cavities, conventional radiology shows poor sensitivity (0.61). High-resolution CT is the most sensitive method for the imaging and classification of temporal bone fractures, including labyrinthine damage and ossicular chain injuries. Only in cases of atypical fractures with an unfavourable relationship to the CT planes, can carefully directed tomography be more effective. In most cases high-resolution CT replaces conventional radiology and should be the method of choice for comprehensive radiological examination of the temporal bone.