A. Gabrielle Bergman

Tibial Stress Reaction in Runners Correlation of Clinical Symptoms and Scintigraphy with a New Magnetic Resonance Imaging Grading System

Medial tibial pain in runners has traditionally been di agnosed as either a shin splint syndrome or as a stress fracture. Our work using magnetic resonance imaging suggests that a progression of injury can be identified, starting with periosteal edema, then progressive mar row involvement, and ultimately frank cortical stress fracture. Fourteen runners, with a total of 18 sympto matic legs, were evaluated and, within 10 days, referred for radiographs, a technetium bone scan, and a mag netic resonance imaging scan. In 14 of the 18 symp tomatic legs, magnetic resonance imaging findings cor related with an established technetium bone scan grading system and more precisely defined the ana tomic location and extent of injury. We identified clinical symptoms, such as pain with daily ambulation and physical examination findings, including localized tibial tenderness and pain with direct or indirect percussion, that correlated with more severe tibial stress injuries. When clinically warranted, we recommend magnetic resonance imaging over bone scan for grading of tibial stress lesions in runners. Magnetic resonance imaging is more accurate in correlating the degree of bone in volvement with clinical symptoms, allowing for more ac curate recommendations for rehabilitation and return to impact activity. Additional advantages of magnetic reso nance imaging include lack of exposure to ionizing ra diation and significantly less imaging time than three- phase bone scintigraphy.

Magnetic resonance imaging of knee cartilage repair.

Cartilage injury resulting in osteoarthritis is a frequent cause of disability in young people. Osteoarthritis, based on either cartilage injury or degeneration, is a leading cause of disability in the United States. Over the last several decades, much progress has been made in understanding cartilage injury and repair. Magnetic resonance (MR) imaging, with its unique ability to noninvasively image and characterize soft tissue, has shown promise in assessment of cartilage integrity. In addition to standard MR imaging methods, MR imaging contrast mechanisms under development may reveal detailed information regarding the physiology and morphology of cartilage. MR imaging will play a crucial role in assessing the success or failure of therapies for cartilage injury and degeneration.

Pediatric elbow fractures: MRI evaluation

Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies.Elbow injuries in children may be difficult to diagnose by routine clinical and radiographic techniques [1, 4, 12, 14]. Diagnostic difficulty is due to the presence of multiple ossification centers of the distal humeral epiphysis and proximal radius and ulna; these are mostly cartilaginous until the age of 11–12 years and therefore invisible on radiographs.Following distal radial and distal tibial physeal fractures, epiphyseal elbow injuries are the most frequent epiphyseal injuries [8, 16]. These fractures tend to be unstable and often require surgical intervention. In addition, lasting sequelae such as cubitus valgus and delayed ulnar nerve palsy can occur if these fractures are not treated properly [8]. Most elbow fractures suspected to be unstable by clinical and radiographic evaluation are operated upon without additional imaging. Occasionally, arthrography or computed arthrography are used to assess epiphyseal extension and cartilaginous malignment [1, 3, 4]. Because of its ability to depict cartilage, MRI provides a noninvasive means of gaining information regarding the nonossified epiphysis. The purpose of this article is to present our preliminary experience using magnetic resonance imaging (MRI) for the detection of articular extension of elbow fractures and determination of displacement of fragments.

MR imaging of ulnar impaction

The ulnar impaction syndrome of the wrist is a well-recognized clinical entity, usually showing distinct radiographic features including a positive ulnar variance and degenerative subchondral changes of the distal ulna, proximal lunate, and proximal triquetrum. Confirmation of the clinical and plain film findings with advanced imaging is often necessary to exclude other entities with a similar clinical presentation. Although arthrography and bone scintigraphy are helpful in this work-up, magnetic resonance imaging (MRI) appears to be both a sensitive and a specific means of evaluation. The imaging studies in four patients with clinically and surgically diagnosed ulnar impaction are described, with emphasis on MRI findings. MRI appears to be the modality of choice in the evaluation of patients with suspected ulnolunate impingement.

Bilateral Stress Fractures of the Anterior Part of the Tibial Cortex. A Case Report

Most stress fractures of the tibia, when treated appropriately, heal without sequelae. A stress fracture of the anterior part of the cortex of the tibia, an uncommon variant, is associated with atypical clinical and radiographic findings, has a propensity for nonunion, and can result in a complete fracture. We report the case of a patient who had chronic, bilateral stress fractures of the anterior part of the tibial cortex. A twenty-one-year-old male college football player who was in his junior year was first seen by us because of a five-year history of recurrent pain in both shins. The pain had worsened in September 1996, during the early part of the football season, when practices were held twice a day. Typically, the pain was most severe when the patient began running but would subside within a few minutes and then return on cessation of weight-bearing activity. The patient had not missed any games or practice sessions. Clinical examination revealed moderate tenderness along the medial border of the distal and middle thirds of the right tibia, extending for a distance of twelve centimeters, and mild tenderness in the corresponding area of the left tibia. The patient had marked bilateral pes planus and rigidity of the midfoot and forefoot. The subtalar and ankle joints had a normal range of motion. Radiographs had been made at regular intervals during the five years before the patient was evaluated in our office, and all had revealed normal findings. A triple-phase isotope bone scan was performed to confirm the provisional diagnosis of a stress fracture. The blood-pool images demonstrated mildly increased radionuclide uptake in the right as compared with the left tibia. The delayed-phase images showed four small, discrete areas of moderately increased uptake along the anterior border of the middle third of the right tibia and …

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Fig. 2A, B. Coronal Tl-weighted (A) and T2-weighted fat saturated (B) spin-echo magnetic resonance images, obtained 1 day after the radiographs, show extensive lesions in the marrow space of the subtrochanteric region and the femoral neck. The expansile lesions in the medial cortex are well seen (arrow), as are also linear and serpiginous lesions in the femoral neck, suggesting a vascular component Fig. 3. Anterior view 99myc bone scan of pelvis and proximal femora, obtained the same day as the radiographs, demonstrates no evidence of increased uptake at the lesions in the proximal left femur. There is slight asymmetry between left and right, which is attributed to patient positioning Clinical information

Tibial stress injury: relationship of radiographic, nuclear medicine bone scanning, MR imaging, and CT Severity grades to clinical severity and time to healing.

PURPOSE To examine the relationship between severity grade for radiography, triple-phase technetium 99m nuclear medicine bone scanning, magnetic resonance (MR) imaging, and computed tomography (CT); clinical severity; and recovery time from a tibial stress injury (TSI), as well as to evaluate interassessor grading reliability. MATERIALS AND METHODS This protocol was approved by the Griffith University Human Research Ethics Committee, the Stanford University Panel on Human Subjects in Medical Research, the U.S. Army Human Subjects Research Review Board, and the Australian Defense Human Research Ethics Committee. Informed consent was obtained from all subjects. Forty subjects (17 men, 23 women; mean age, 26.2 years ± 6.9 [standard deviation]) with TSI were enrolled. Subjects were examined acutely with standard anteroposterior and lateral radiography, nuclear medicine scanning, MR imaging, and CT. Each modality was graded by four blinded clinicians. Mixed-effects models were used to examine associations between image severity, clinical severity, and time to healing, with adjustments for image modality and assessor. Grading reliability was evaluated with the Cronbach α coefficient. RESULTS Image assessment reliability was high for all grading systems except radiography, which was moderate (α = 0.565-0.895). Clinical severity was negatively associated with MR imaging severity (P ≤ .001). There was no significant relationship between time to healing and severity score for any imaging modality, although a positive trend existed for MR imaging (P = .07). CONCLUSION TSI clinical severity was negatively related to MR imaging severity. Radiographic, bone scan, and CT severity were not related to time to healing, but there was a positive trend for MR imaging.

Joint motion in an open MR unit using MR tracking.

A system for active scan plane guidance during kinematic magnetic resonance (MR) examination of joint motion was developed utilizing an external tracking coil and MR tracking software. In a phantom study and during upright, weight‐bearing, physiologic knee flexion, the external tracking coil maintained the scan plane through desired structures. Thus, MR tracking provides a robust method to guide the scan plane during MR imaging of active joint motion.J. Magn. Reson. Imaging 1999;10:8–14.

Polyostotic fibrous dysplasia with severe pathologic compression fracture of L2

A case of a progressive pathologic compression fracture of L2 due to polyostotic fibrous dysplasia is presented. Such unusually severe involvement, requiring decompression and surgical fusion, in the absence of significant recent or remote trauma, has not previously been reported.

Risk factors for tibial stress injuries: a case-control study.

Objective:To identify physical and behavioral characteristics related to the incidence of tibial stress injuries (TSIs). Design:Case–control study. No clinical care was conducted. Setting:Research laboratories in the San Francisco (the United States) and Gold Coast (Australia) areas. Participants:Forty-eight patients (21 men and 27 women) with acute TSI, and 36 (16 men and 20 women) age-matched, sex-matched, height-matched, weight-matched, and activity-matched controls with no history of TSI. Independent Variables:Height, weight, body mass index, bone, lean and fat mass, lower limb alignment anomalies, foot type, orthotics, calcium, recent weight change, menstrual history, oral contraceptive use, medications, smoking, alcohol, sleep, training type, and intensity. Differences in continuous variables were tested using 1-way analysis of variance. Categorical variable comparisons were performed with Fisher exact test. Main Outcome Measure:Tibial stress injury. Results:Tibial stress injury cases had 2.7% more fat (P < 0.001) and 2.6% less muscle (P < 0.001) as well as lower trochanteric bone mineral content (BMC) (P < 0.001), lumbar spine (LS) area (P < 0.001), femoral neck BMC (P < 0.001), length (P < 0.05), area (P < 0.001), cortical width (P < 0.01), cross-sectional moment of inertia (P < 0.001), and index of bending strength (P < 0.001) than controls. Controls had lower LS BMC (P < 0.01), length (P < 0.001), and broadband ultrasound attenuation (P < 0.001). The use of orthotic insoles was more prevalent in TSI cases than controls (25% vs 5.6%, respectively; P < 0.02), as were foot anomalies (56.3% vs 27.8%, respectively; P = 0.01). Conclusions:Tibial stress injury cases had lower lean and higher fat mass, a tendency for smaller bones, and for foot anomalies compared with uninjured matched controls. Bone mineral density was normal for both groups. Clinical Relevance:Enhancing lean mass and limiting gains in fat may provide some protection against TSI. Individuals with small skeletal frames are advised to increase training loads particularly gradually and to reduce training intensity at the first sign of pain in the shins.