MRI of anterior cruciate ligament injuries and associated findings in the pediatric knee: changes with skeletal maturation

OBJECTIVE: The objective of our study was to evaluate the MRI characteristics of anterior cruciate ligament (ACL) injuries and associated findings relative to skeletal maturity. We also contrast the frequency of findings in this younger population to adult data. MATERIALS AND METHODS: Eighty-two consecutive knees with an MRI report diagnosis of ACL injury (partial tear, sprain, or complete tear) or tibial spine avulsion fracture imaged over 4 years were retrospectively reviewed. Patients were grouped by degree of skeletal maturity as determined from the MR images. The examinations were reviewed for the type of ACL injury, secondary imaging findings, and associated knee injuries. Findings were correlated to skeletal maturity, and frequencies were compared with adult data. RESULTS: ACL injuries were more common in boys in the skeletally immature group, but more common in girls in the skeletally mature group (p = 0.03). Tibial spine avulsion fractures were most common in skeletally immature patients (p < 0.01), whereas complete tears of the ACL were most common in skeletally mature patients. Associated injuries were less common in the skeletally immature group, but this trend did not reach statistical significance. Most secondary signs of ACL injuries occurred at similar rates in all groups with frequencies similar to those reported in adults. CONCLUSION: ACL injuries in skeletally immature patients are seen more often in boys. Tibial avulsion fractures and partial tears are more common in younger, less rigid skeletons that may absorb the forces of trauma. As children mature, complete ACL tears and associated injuries occur in frequencies approaching those patterns seen in adults. Similarly, skeletally mature girls are affected more often than mature boys.     

Comparing sonography with MR imaging of apophyseal injuries of the pelvis in four boys

OBJECTIVE: The purpose of this article is to describe the sonographic appearance of avulsion of the apophyses of the anterosuperior and anteroinferior iliac spines of the pelvis. CONCLUSION: Sonography can show apophyseal injuries of the pelvis and can be used instead of MR imaging.     

Isolated popliteus tendon avulsion in skeletally immature patients

Four cases of isolated popliteus tendon avulsion in skeletally immature patients that presented to our institution over an 11 month period are reviewed. All the cases had characteristic features on the initial knee radiograph and the diagnosis was confirmed using magnetic resonance imaging (MRI). A brief literature review is included. The aim of the present study was to raise awareness of the radiographic findings of isolated popliteus tendon avulsion in adolescent patients.     

Acute Knee Injuries in Young Athletes

In brief Juvenile and adolescent athletes brief are prone to most of the same knee injuries as adults, but skeletal immaturity makes them vulnerable to certain knee injuries unique to their age and level of maturation. Usually these injuries involve the growing cartilage on the joint surface or at the epiphyseal plate. A stress that would cause a ligament sprain or muscle strain in an adult may cause a growth plate fracture or avulsion in a skeletally immature athlete.     

Sports-related acute and chronic avulsion injuries in children and adolescents with special emphasis on tennis

Acute and chronic sports-related muscle and tendon injuries are not infrequent in youngsters. In particular, the physis is prone to trauma as it constitutes the weakest part of the immature skeleton. The type of sports activity determines the location of the lesion. Most commonly, apophyses of the hip and pelvis are subject to avulsion. The purpose of this paper is to give a short overview of the pathogenesis, location, prevalence and imaging characteristics of acute and chronic avulsion injuries in the immature skeleton, with special emphasis on tennis-related injuries. Tennis-related injuries particularly involve apophyses of the ischial tuberosity, the anterior inferior or superior iliac spine and the iliac crest.     

Imaging features of avulsion injuries.

Avulsion injuries are common among participants in organized sports, especially among adolescent participants. Imaging features of both acute and chronic avulsion injuries of the pelvis, knee, ankle and foot, shoulder, and elbow were evaluated to help distinguish these injuries from more serious disease processes such as neoplasm and infection. At radiography, acute injuries (ie, those resulting from extreme, unbalanced, often eccentric muscular contractions) may be associated with avulsed bone fragments, whereas subacute injuries have an aggressive appearance that may include areas of mixed lysis and sclerosis. Chronic injuries (ie, those resulting from repetitive microtrauma or overuse) or old inactive injuries may be associated with a protuberant mass of bone and may bear a striking resemblance to a neoplastic or infectious process. Although not usually required, computed tomography is helpful in the diagnosis if radiographic findings are equivocal or if the injury is not in the acute phase. MR imaging is best suited for the evaluation of injuries to muscles, tendons, and ligaments. Recognition of characteristic imaging features and familiarity with musculotendinous anatomy will aid in accurate diagnosis of avulsion injuries.     

Apophyseal damage in adolescent athlete

The increasing demands on the adolescent athlete in high performance sports puts high biomechanical stress on the growing structures of the active and passive locomotor system. The "growing factor" itself increases stretching forces on tendon insertions, which are often overloaded when a physical demanding sport is performed additionally. The apophysis is an ossification nucleus near the tendon insertion, which appears before the growing age resumes and these apophysis finally fuses with the adjacent bone. The tensile forces from vigorous sports activity leads to a chronic or acute avulsion of the ossifying tendon insertion. The radiological appearance of this apophyseal damage with ossification and osteolytic processes is sometimes difficult with respect to differential diagnoses. Apophyseal impairment is associated with pain, tenderness to palpation and decreased muscle function. If it is not diagnosed and treated properly it can lead to end of career in many adolescent athletes.     

Imaging the infrapatellar tendon in the elite athlete

Extensor mechanism injuries constitute a major cause of anterior knee pain in the elite athlete. Sonography and magnetic resonance imaging (MRI) are the imaging methods of choice when assessing the infrapatellar tendon. A comprehensive imaging review of infrapatellar tendon normal anatomy, tendinopathy, and partial/full-thickness tendon tears is provided. The value of imaging the infrapatellar tendon in clinical practice, including whether sonography can predict symptoms in asymptomatic athletes, is discussed. Acute avulsion fractures, including periosteal sleeve avulsion, and chronic avulsion injuries, including Sinding-Larsen-Johansson and Osgood-Schlatter syndromes, are shown. Mimics of infrapatellar tendon pathology, including infrapatellar plica injury, patellar tendon-lateral femoral condyle friction syndrome, and Hoffa's syndrome, are illustrated.     

Multiple osteochondroses and avulsion fracture of anterior superior iliac spine in a soccer player

Apophysitis describes a chronic traction injury at the insertion site of a tendon. There is a gradual onset of pain with no clear history of injury. Without adequate preventive methods, an avulsion fracture may result. The case is here reported of an apophyseal avulsion fracture of the anterior superior iliac spine in an adolescent caused by playing football before the end of treatment for apophysitis. An open reduction and internal fixation was performed followed by a rehabilitation programme. No complications occurred, and the patient had returned to his previous level of sporting activity after six weeks.     

Pediatric athlete hip disorders

Injuries of the hip and pelvis in pediatric athletes are receiving increased attention. The majority of injuries are soft tissue injuries or apophyseal injuries that heal with nonoperative supportive treatment. Unique injury patterns can be seen in patients who have underlying pediatric hip disorders such as slipped capital femoral epiphysis, and Legg-Perthes disease. With the advent of hip arthroscopy and the development of more advanced imaging of the hip through MR arthrography, internal derangements of the hip such as labral tears, loose bodies, and chondral injuries are being diagnosed and treated with increased frequency. This article reviews the more common injuries of the hip and pelvis in pediatric athletes.     

Current Concepts of Diagnosis and Management of ACL Injuries in Skeletally Immature Athletes

Abstract

Anterior cruciate ligament (ACL) injuries in skeletally immature athletes are encountered with increasing frequency. The management of such injuries is controversial. Nonsurgical management often results in functional instability and a higher risk of meniscal and chondral injury to the knee. Conventional methods of ACL reconstruction carry the risk of growth disturbance because of iatrogenic damage to the physes around the knee. Multiple cases of growth disturbance have been reported. This article discusses the relevant anatomy, natural history, risk factors, treatment, and prevention of ACL injuries in skeletally immature patients. Surgical treatment is based on physiologic age. For prepubescent patients, we recommend physeal-sparing combined intra-articular/extra-articular reconstruction with autogenous iliotibial band. In adolescent patients with significant growth remaining, we recommend transphyseal ACL reconstruction with hamstrings autograft and fixation away from the physes. In older adolescent patients, we recommend conventional adult ACL reconstruction with autogenous hamstrings or patellar tendon.     

Radiology of posterior lumbar apophyseal ring fractures: Report of 13 cases

Summary The authors report radiological findings in 13 cases of avulsion of the posterior lumbar apophyseal ring. The lesion affected young adults in 10 cases and adolescents in 3 cases. The lesion involved the inferior endplate of L4 in 11, and of L5 in 1 patient, and of L3 in 1 patient. 6 patients presented with unilateral sciatica, 3 with bilateral sciatica, and 4 with low back pain. Acute spinal trauma was evident only in 2 adolescents. Radiological recognition of the lesion was possible on plain films in 9 cases. CT demonstrates association of avulsion of the posterior vertebral apophyseal ring and herniated disc in all cases. Avulsion of the posterior apophyseal ring has to be differentiated from posterior longitudinal ligament, annulus, or herniated disc calcifications, as well as from posterior degenerative ridge osteophytes. Controversy about physiopathology of the lesion remains: weakness of the apophyseal ring during childhood and in patients with Scheuermann's disease may explain avulsion of the apophyseal ring in association with median disc herniation.     

Hip ultrasound

In newborns, US has an established role in the detection and management of developmental dysplasia of the hip. Later in childhood, when the limping child is a major diagnostic dilemma, US is extremely helpful in the identification of the varied disease processes underlying this condition, as transient synovitis, septic arthritis, Perthes disease and slipped femoral capital epiphysis. In adolescent practicing sporting activities, US is an excellent means to identify apophyseal injures about the pelvic ring, especially when avulsions are undisplaced and difficult-to-see radiographically. Later on, in the adulthood, US is an effective modality to diagnose tendon and muscle injuries about the hip and pelvis, identify effusion or synovitis within the hip joint or its adjacent bursae and guide the treatment of these findings. The aim of this article is to provide a comprehensive review of the most common pathologic conditions about the hip, in which the contribution of US is relevant for the diagnostic work-up.     

Humeral avulsion of the anterior band of the inferior glenohumeral ligament with associated subscapularis bony avulsion in skeletally immature patients

OBJECTIVE: We describe the imaging appearances of an injury complex occurring in the skeletally immature patient consisting of an avulsion fracture of the subscapularis attachment to the lesser tuberosity and avulsion of the inferior glenohumeral ligament (HAGL) which in two cases was associated with a bony fragment (BHAGL). CONCLUSION: MR imaging was able to diagnose correctly this atypical injury complex which had not been suspected clinically or on the radiographs.     

MR imaging of rectus femoris origin injuries

Objective To describe the MR imaging findings of acute and chronic rectus femoris origin (RFO) injuries.Materials and methods A retrospective review of pelvic and hip MR imaging procedures was performed over a 4-year period for detection of cases with injuries to the RFO. Subjects were classified as having either acute or chronic symptoms. MR imaging studies, radiographs, CT scans, radiology reports, medical records, and operative notes were reviewed. Imaging analysis was directed to assess injuries affecting the direct and indirect heads of the RFO. Concurrent osseous, cartilaginous and musculotendinous injuries were tabulated.Results The incidence of RFO injuries on MR imaging was 0.5% (17/3160). With the exception of one case of anterior inferior iliac spine apophysis avulsion and partial tear of the direct head of RFO, all subjects had indirect head of RFO injuries (acute injury 8/9, chronic injury 8/8). Partial tear of the direct head of RFO was less frequently seen (acute injury 3/9, chronic injury 2/8). Partial tears of the conjoint tendon were least frequent (acute 1/9, chronic 2/8). No full-thickness tears of the RFO were noted. Associated labral tears were seen in only one case, with no other concomitant abnormality of the articular cartilage or surrounding soft tissues. All RFO injuries were treated non-operatively.Conclusion Injuries of the RFO are uncommon on MR examinations of pelvis/hips and may occur in a sequence progressing from indirect head injury to involvement of direct head and conjoint tendon in more severe cases.     

Acute tibial tubercleavulsion fractures

Acute tibial tubercle avulsion fractures are commonly seen in athletes involved with jumping sports, especially basketball. These injuries typically occur in well-muscled, mature-appearing boys, 15 to 16 years of age, who generate high tensile forces at the tubercle junction. Possible associated injuries include patellar and quadriceps tendon avulsions, as well as collateral and cruciate ligament and meniscal damage. Treatment is based on the magnitude of injury. Recovery is rapid and the outcome is usually excellent, even in type III injuries.     

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.     

Management of anterior cruciate ligament injuries in skeletally immature adolescents

Anterior cruciate ligament (ACL) injuries in skeletally immature adolescents are bein diagnosed and reported with increasing frequency. Nonoperative management of midsubstance ACL injuries in adolescent athletes frequently results in a high incidence of giving-way episodes, recurrent meniscal tears, and early onset of osteoarthritis. An intraarticular ACL reconstruction (using the central 10-mm patellar tendon graft) in young athletes approaching skeletal maturity provides predictable excellent knee stability, and the athletes are able to return to competitive sports with a decreased risk of recurrent meniscal and/or chondral injury. Guidelines for the management of ACL injuries in skeletally immature adolescents are presented.     

Advanced imaging of glenohumeral instability: the role of MRI and MDCT in providing what clinicians need to know

The inherently unstable anatomy of glenohumeral (GH) joint predisposes it to shoulder dislocation. Shoulder dislocation can occur either due to acute trauma or due to chronic microtraumas in the setting of underlying morphological abnormality. A plain radiograph is the initial imaging modality for diagnosis and management of shoulder dislocation and its associated osseous abnormalities such as Hill-Sachs deformity or osseous Bankart lesion. However, advanced imaging techniques such as multidetector CT (MDCT) with three-dimensional (3D) volume rendering and MRI can be helpful in further characterization of osseous abnormalities and detection of associated soft tissue injuries, respectively. These additional findings may be useful for optimal surgical repair for GH joint stabilization. In this pictorial essay, we present the clinically relevant osseous and soft tissue pathologies in various types of shoulder dislocation, with emphasis on pathologies that can be demonstrated using advanced imaging examinations. Discussed pathologies include glenoid fractures, labral tears, Bankart lesion, Hill-Sachs defect, Perthes lesion, anterior labral posterior sleeve avulsion (ALPSA), glenolabral articular disruption (GLAD), humeral avulsion of the glenohumeral ligament (HAGL), Kim lesion, and other associated soft tissue and nerve injuries.     

Avulsion fractures of the pelvis in children: a report of 32 fractures and their outcome

Avulsion injuries of the apophyses of the pelvis are mainly athletic injuries and are usually seen in adolescents. In a series of 80 pelvic fractures in children seen and managed in The Royal Liverpool Children's Hospital, Alder Hey, in the last 10 years, 32 avulsion fractures in 25 patients were diagnosed and treated. Twenty-two of these patients were followed for an average of 44 months (range 4–120 months). Eight (33%) were girls, a higher proportion than in other published series. The average age of the children was 13.8 years. These fractures, though generally regarded as trivial injuries, have left disability persisting into adult life, with limitation of sporting ability in 10 of the 22 patients and persistent symptoms in 6, mostly in those with ischial avulsion injuries. Fourteen patients with acute injuries needed hospitalisation, with an average stay of 5 days. The other 11 were suffering from chronic traction injuries sustained in sport. This distinction between acute and chronic injuries has not been emphasized in the other reviews. The radiological appearances, diagnostic problems and morbidity are discussed in order to increase awareness of these injuries.