Osseous and myotendinous injuries about the knee

Osseous injuries may be articular, extra-articular, or physeal, and may be related to direct trauma, avulsion forces, or chronic microtrauma. Muscle and tendon injuries about the knee may occur alone or in association with more significant osseous and ligament injuries. Radiographs or computed radiography images remain an important screening technique for patients who have suspected knee injuries. After initial radiographs, MR imaging has become the most common modality for detection and complete evaluation of osseous and soft-tissue injuries about the knee when those radiographs and other techniques do not demonstrate clearly the type and extent of injuries. This article focuses on the usefulness of MR imaging in the detection, classification, and management of bone, muscle, and tendon injuries of the knee.     

Imaging of triathlon injuries

Injuries in triathletes are common and are mostly overuse injuries. Rotator cuff tendinitis is the most common complaint from swimming, but the incidence of tendinopathy and rotator cuff tears on magnetic resonance imaging is comparable in triathletes without and with shoulder pain. Cycling injuries are mainly to the knee, including patellar tendinosis, iliotibial band syndrome, and patellofemoral stress syndrome, and to the Achilles tendon and the cervical and lumbar spine. Running is associated with most injuries in triathletes, during both training and racing, causing the athlete to discontinue the triathlon. In addition to knee injuries from running, triathletes may also develop foot and ankle, lower leg, and hip injuries similar to single-sport distance runners. Some injuries in triathletes may be mainly symptomatic during one of the three sports but are exacerbated by one or both of the other disciplines.     

关节积脂血征的影像学表现

目的：分析外伤所致关节积脂血征的X线、CT和MRI表现,总结其影像学特征表现。方法：回顾性分析46例关节积脂血征的X线、CT和MRI特点,其中膝关节32例、髋关节4例、肩关节4例、踝关节5例及肘关节1例。结果：仅4例在X线上有特征性表现,CT或MRI上46例关节积脂血征患者均有关节内骨折,关节积脂血征CT和MRI表现为关节囊内单液-液平面或双液-液平面,单液-液平面及双液-液平面的不同成份在CT和MRI上密度和信号不同,但上层均为脂肪。结论：关节积脂血征在CT和MRI上具有特征性表现,可做出明确诊断,关节积脂血征均与关节内骨折并存,可作为关节内骨折的可靠间接征象。     

Sports injuries of the hip

With the increasing emphasis on physical activity and physical fitness, the human body is being subjected to an increasing number of stresses, leading to a variety of injuries to the musculoskeletal system. These may be the result of direct trauma to the soft tissues or bony skeleton or may be seen as the result of continued subclinical trauma and stresses (fatigue fractures), or the effects of forceful contraction of muscles (avulsion injuries). Since much of the physical activity involves the lower limbs, stresses on or around the hip are producing, in ever-increasing numbers, sports-related injuries of which the physician and radiologist should be aware. This article explores a variety of sports-related injuries around the hip and identifies the various methods of investigation that may be used in their diagnosis as well as their characteristic radiographic appearance.     

Magnetic resonance imaging in the diagnosis of knee injuries

Of all the magnetic resonance examinations performed for studying musculoskeletal disease, magnetic resonance imaging (MRI) of the knee is the most frequently requested examination. It has replaced knee arthrography in the vast majority of clinical situations. MRI of the knee is currently the diagnostic procedure of choice for the diagnosis of injuries to the menisci, ligaments, and tendons as well as bone bruises and occult fractures in the knee. This review article discusses the technical aspects of performing the MRI examination of the knee. It also discusses the magnetic resonance criteria for diagnosing meniscus tears, ligament and tendon disruptions, and bone bruises.     

Imaging findings in the dominant shoulder of throwing athletes: comparison of radiography, arthrography, CT arthrography, and MR arthrography with arthroscopic correlation

OBJECTIVE: Conventional radiography, arthrography, CT arthrography, and MR arthrography--including use of the abduction and external rotation position--were compared, with arthroscopic correlation, to determine the spectrum of abnormalities encountered and the relative benefits of each imaging method in the evaluation of shoulder lesions occurring in 17 throwing athletes. SUBJECTS AND METHODS: Each of 36 athletes with shoulder pain aggravated by abduction and external rotation was examined in a single visit during which conventional radiography, arthrography, CT arthrography, and MR arthrography were performed. In 17 of these athletes, imaging findings were compared with those at arthroscopy. All images were independently evaluated by two groups of musculoskeletal radiologists. RESULTS: Structures found to be affected were, in decreasing order of frequency, the following: the posterosuperior labrum, supraspinatus tendon, infraspinatus tendon, humeral head, glenoid cavity and rim, acromioclavicular joint, anteroinferior capsulolabral complex, biceps tendon, and subscapularis tendon. MR arthrography without and with abduction and external rotation yielded the highest sensitivity and specificity for all lesions with the exceptions of bone sclerosis and enthesophytes (which were best seen with CT arthrography). MR arthrography with abduction and external rotation was most accurate for diagnosis of rotator cuff and anteroinferior capsulolabral complex tears. CONCLUSION: On the basis of these preliminary results, we believe that MR arthrography with abduction and external rotation should be part of the imaging evaluation of shoulder pain in throwing athletes, owing to the high sensitivity of this imaging technique.     

Conventional radiography, CT, and MR imaging in patients with hyperflexion injuries of the foot: diagnostic accuracy in the detection of bony and ligamentous changes

OBJECTIVE: The goal of this study was to compare the capabilities of conventional radiography, CT, and MR imaging in revealing ligamentous and bony changes in patients after hyperflexion injuries. SUBJECTS AND METHODS: Forty-nine patients with hyperflexion injuries of the foot were included in our study. Conventional radiography, weight-bearing radiography, CT, and MR imaging were performed. All images were reviewed with respect to ligamentous and bony abnormalities and alignment alterations. Eleven patients with joint malalignment underwent surgery, which is considered the gold standard in these patients. Five patients with joint malalignment refused surgery. RESULTS: For all 49 patients, conventional radiographs revealed 33 metatarsal and 20 tarsal fractures. Eight patients presented with tarsometatarsal joint (Lisfranc's joint) malalignment. Weight-bearing radiographs showed joint malalignment in the same eight patients only. CT showed 41 tarsal fractures and 53 metatarsal fractures. Joint malalignment was evident in 16 patients. MR imaging revealed 41 metatarsal fractures and 18 metatarsal bone bruises. Tarsal bones were fractured at 39 sites and there were nine tarsal bone bruises. Metatarsal fractures were mostly localized in the second metatarsal bone; tarsal fractures, in the cuboid. Joint malalignment was evident in 16 patients; in 11 of these 16 patients, Lisfranc's ligament was disrupted. Surgery confirmed bony and ligamentous changes and joint malalignment in 11 patients. CONCLUSION: Conventional radiographs including weight-bearing images are not sufficient for routine diagnostic workup of patients with acute hyperflexion injuries of the foot. CT should serve as the primary imaging technique for such patients.     

Imaging pediatric sports injuries: lower extremity

Injuries to pediatric athletes, which are becoming increasingly common, take the form of acute injuries and chronic overuse injuries. Acute injuries of the lower extremity include avulsions of the pelvic apophyses, muscle-tendon injuries, transient dislocation of the patella, ankle sprains, and acute tears of the anterior cruciate ligament and menisci. Magnetic resonance (MR) imaging of the latter 2 injuries should approach the accuracy of MR imaging of the adult knee. Chronic overuse injuries of the lower extremity in this age group include stress fractures, which are most common in the tibia; ankle impingement syndromes; osteochondritis dissecans of the knee and osteochondral lesions of the talus; and traction apophysitis, most commonly presenting as Osgood-Schlatter disease and Sinding-Larsen-Johannson disease, affecting the patellar tendon. Imaging findings of all these lesions are characteristic, and allow radiologists to assist their clinical colleagues in diagnosing and treating pediatric athletic injuries.     

Diving-type injury of the cervical spine: contribution of computed tomography to management.

We have utilized computed tomography (CT) in addition to conventional radiography for evaluation and as a guide to management of serious diving injuries to the cervical spine. This technique has proven to be invaluable in the initial assessment and further clinical management of this type of injury. A classification of these injuries and associated fractures is presented based on CT appearance. Representative cases are presented comparing standard radiography and CT.     

Computed tomography of the bony pelvis: a protocol for multiplanar imaging. Part II: Trauma

Fractures of the pelvis are frequently complex, and conventional radiography, including special views, may be inadequate for accurate diagnosis. One must ascertain the integrity of the anterior and posterior columns, hip joint spaces for debris, and the medial walls of the acetabula. Computed tomography (CT) is indicated early in management, whenever initial plain radiographs reveal complex or questionable fractures of any of these structures. I have developed a unique, multiplanar reformatting protocol using oblique reformations of transverse CT images. This allows clear spatial perception of the nature and extent of pelvic fractures. Twelve selected patients with complex pelvic fractures, as determined by conventional and special radiographs, underwent transaxial and multiplanar CT scanning according to the devised protocol, using transverse CT and multiplanar reformation of the pelvis. The planes of reformation are illustrated by drawings, and multiplanar radiographs demonstrate the injuries. Nine of the 12 patients had additional injuries revealed, over and above the abnormalities shown by CT, by the use of the reformatting technique I describe. Also fractures or fracture dislocations of the sacroiliac joints were diagnosed in four of the 12 patients using CT but in six patients when reformatted images were examined.     

骨显像对未分化脊柱关节病的诊断价值

目的 探讨骶髂关节/骶骨放射性比值对未分化脊柱关节病（uSpA）的诊断价值。方法 对临床有腰腿症状、类风湿因子（RF）阴性、骶髂关节X线和CT检查可疑的76例不同年龄受检者的152个关节,进行SPECT全身骨显像及骶髂关节局部显像,取得不同部位的两组放射性比值。并与正常值比较。结果 76例uSpA患者152个骶髂关节中X线平片有16个异常,CT检查有41个异常,骨显像有94个骶髂关节/骶骨放射性比值升高,39例患者有髋关节和（或）胸锁关节、腰椎等其他关节病变,无异常发现19例。结论 核素骨显像诊断uSpA较X线及CT灵敏。     

The application of cone-beam CT in the aging of bone calluses: a new perspective?

In the forensic and anthropological fields, the assessment of the age of a bone callus can be crucial for a correct analysis of injuries in the skeleton. To our knowledge, the studies which have focused on this topic are mainly clinical and still leave much to be desired for forensic purposes, particularly in looking for better methods for aging calluses in view of criminalistic applications. This study aims at evaluating the aid cone-beam CT can give in the investigation of the inner structure of fractures and calluses, thus acquiring a better knowledge of the process of bone remodeling. A total of 13 fractures (three without callus formation and ten with visible callus) of known age from cadavers were subjected to radiological investigations with digital radiography (DR) (conventional radiography) and cone-beam CT with the major aim of investigating the differences between DR and tomographic images when studying the inner and outer structures of bone healing. Results showed how with cone-beam CT the structure of the callus is clearly visible with higher specificity and definition and much more information on mineralization in different sections and planes. These results could lay the foundation for new perspectives on bone callus evaluation and aging with cone-beam CT, a user-friendly and skillful technique which in some instances can also be used extensively on the living (e.g., in cases of child abuse) with reduced exposition to radiation.     

Get a kick out of this: the spectrum of knee extensor mechanism injuries

At the end of this article, the reader should be able to (1) recognise normal anatomy and anatomical variants of the extensor mechanism of the knee on various imaging modalities, including plain film, ultrasound and MRI; (2) diagnose a broad spectrum of EM injuries in adult and paediatric patients including patellar and quadriceps tendinopathy, Osgood-Schlatter disease, Sindig-Larsen-Johansson syndrome, chondromalacia patellae and patellar fractures on various imaging modalities; and (3) appreciate the important role of imaging in the diagnosis of musculoskeletal injuries.     

Hip and pelvic injuries in the young athlete

Hip and pelvic injuries are relatively rare in the young athlete. Contusions and musculotendinous sprains are the most common injuries about the hip and pelvis. Apophyseal avulsion fractures and stress fractures are the most frequently encountered skeletal injuries. Each of these entities can be successfully treated with guided physical therapy following conservative management with rest, anti-inflammatory medications, and ice massage until the patient is pain free. Epiphyseal, diaphyseal, or pathologic fractures are rare entities that are secondary to violent trauma. These injuries are severe and often require operative intervention. Femoral neck fractures have a high rate of complications from avascular necrosis, nonunion, or malunion. Pelvic fractures have frequent associated genitourinary, abdominal, neurologic, and musculoskeletal injuries. Pathologic fractures are most commonly secondary to benign lesions, such as unicameral bone cysts, and less likely owing to malignancy. Finally, in children with hip pain during athletic activities, even with antecedent trauma, the sports clinician must screen for slipped capital femoral epiphysis, Perthes' disease, congenital subluxation of the hip, toxic synovitis, systemic neoplasia, or infectious process.     

MR imaging in the evaluation of trauma

Although computed tomography (CT) and radiographs are primary modalities in the evaluation of patients undergoing trauma, the indications for magnetic resonance (MR) imaging in trauma have grown. MR has been most useful in patients with central nervous system or musculoskeletal trauma. In head trauma, MRI is most useful in the evaluation of patients with neurologic deficit greater than that expected from CT findings. MRI is useful in such situations because of its improved sensitivity to nonhemorrhagic and microhemorrhagic lesions as well as posterior fossa pathology. In the spine, MRI provides detailed assessment of the disc space, spinal cord, and ligamentous structures; guiding therapeutic decisions; and offering prognostic information. In the musculoskeletal system, MRI offers a noninvasive means of imaging injuries to the muscles, tendons, ligaments, and cartilage of the knee, shoulder, ankle, and elbow. Additionally, MRI may define a subset of radiographically occult bony injuries.     

Imaging of lower extremity stress fracture injuries

Stress reactions and stress fractures in the lower extremities occur frequently in military and athletic populations. As the clinical symptoms of stress fracture may mimic other less severe musculoskeletal injuries, the diagnosis of stress fracture can often be delayed. The following article reviews the characteristics, advantages and disadvantages of the various imaging tools available to detect stress fracture of the lower limbs in order to clarify their utility when diagnosing this condition. Plain radiography, the primary imaging tool for diagnosing suspected stress injuries, may not detect stress fracture injury until fracture healing is well underway. In some cases of suspected stress fracture, this delay in diagnosis can lead to catastrophic fracture and surgical intervention. Bone scintigraphy has long been recommended for the diagnosis of stress fracture, claiming that skeletal scintigraphy is 100% sensitive for the detection of stress fracture. However, there is a potential for a false negative examination and findings might be nonspecific as tumours or infections may mimic stress injury. In addition, bone scintigraphy involves ionizing radiation and it should not be used whenever there is an alternative. Computed tomography (CT) provides exquisitely fine osseous detail, but should be reserved only for specific indications because it also involves ionizing radiation. Magnetic resonance (MR) imaging, which is noninvasive, has no ionizing radiation, is more rapidly performed than bone scintigraphy, and should be the method of choice for stress fracture diagnosis whenever it is available. However, using MR imaging demands an experienced diagnostician in order to decrease reported false-positive injuries. The ultrasonography technique, which is being used increasingly in the evaluation of the musculoskeletal system has recently been shown to have some potential in the diagnosis of stress fracture; however, currently the imaging modalities are insufficient. The peripheral quantitative CT (pQCT) device, which has been developed to specifically assess skeletal status of the extremities, provides data on bone geometry, strength and density. However, the pQCT needs further evaluation prior to being considered for use in diagnosis stress changes in bone. This article reviews the utility of each of the imaging modalities currently available to detect stress fracture injuries of the lower extremities, as well as other utilization factors, which include exposure to ionizing radiation, the ability to detect early- and late-stage reactions in the bone and surrounding soft tissues, and the ability to differentiate between different types of bone lesions.     

CT assessment of the prevalence of retinacular injuries associated with hindfoot fractures

Objective

To determine the incidence of injuries to the flexor and peroneal retinacula in hindfoot fractures as demonstrated on ankle computed tomography (CT).

Materials and methods

Study patients were identified via review of CT records at a single institution. CT scans were retrospectively reviewed and compared with surgical reports.

Results

Hindfoot fractures undergoing CT showed flexor retinacular injuries in 23.7% of cases and peroneal retinacular injuries in 10.2%. The posterior tibial tendon was partly torn in 4.2% of cases, and entrapped between fracture fragments in 16.1%. The peroneal tendon was rarely injured, being entrapped in 1.7% of cases. Pilon, distal tibial shaft, malleolar, talar, and calcaneal fractures were all associated with retinacular injuries. CT findings correlated well with surgical findings; there were no false-positive CT findings, and only 1 false-negative finding, a posterior tibial tendon that was entrapped at surgery, but in a normal position on the CT.

Conclusions

Retinacular injuries are commonly demonstrated on CT in patients with ankle fractures. The contribution of these injuries to fracture outcomes is unknown.     

Hip injuries in athletes

Hip injuries are common in athletes, and there is an extensive differential diagnosis of potential causes. This article reviews the anatomy of the hip, and discusses the imaging findings of hip pathology in athletes including skeletal, intraarticular, and extra-articular abnormalities. The role of radiography, computed tomography (CT), magnetic resonance (MR) imaging, MR arthrography, CT arthrography, and sonography in evaluating each condition is discussed.     

Upper extremity injuries in the paediatric athlete

Injuries to the upper extremity in paediatric and adolescent athletes are increasingly being seen with expanded participation and higher competitive levels of youth sports. Injury patterns are unique to the growing musculoskeletal system and specific to the demands of the involved sport. Shoulder injuries include sternoclavicular joint injury, clavicle fracture, acromioclavicular joint injury, osteolysis of the distal clavicle, little league shoulder, proximal humerus fracture, glenohumeral instability and rotator cuff injury. Elbow injuries include supracondylar fracture, lateral condyle fracture, radial head/neck fracture, medial epicondyle avulsion, elbow dislocation and little league elbow. Wrist and hand injuries include distal radius fracture, distal radial physeal injury, triangular fibrocartilage tear, scaphoid fracture, wrist ligamentous injury thumb metacarpalphalangeal ulnar collateral ligament injury, proximal and distal interphalangeal joint injuries and finger fractures. Recognition of injury patterns with early activity modification and the initiation of efficacious treatment can prevent deformity/disability and return the youth athlete to sport.