Martina Lohman

MRI abnormalities of foot and ankle in asymptomatic, physically active individuals.

Abstract Objective. To assess MRI changes in the ankle and foot after physical exercise. Design and patients. Nineteen non-professional marathon runners and 19 age- and sex-matched controls volunteered for the study. All had ankle and foot MR images (1.5 T) taken in three perpendicular planes (STIR, T2F and T1FS sequences) within 3 h of running a full-length marathon (42.125 km). Three radiologists independently analysed the groups on a masked basis using a predefined form. Results. Severe bone marrow oedema was seen in one and slight bone marrow oedema in three marathon runners. Slight bone marrow oedema was found in three control subjects. Signal alteration within the soleus muscle, consistent with a grade 1 strain, was found in one marathon runner. Small punctate hyperintensities within the Achilles tendon were seen in 26% of the marathon runners and in 63% of controls (P=0.016). An increased amount of fluid in the retrocalcaneal bursa was found in one control and in none of the marathon runners. Small amounts of fluid in the retrocalcaneal bursa were seen in 68% of marathon runners and in 53% of controls. Grade 1 or 2 peritendinous joint fluid was found around 22% of tendons, among both marathon runners and controls, most often involving the tendon sheath of the flexor hallucis longus muscle. An increased amount of joint fluid was noted in 34% of the joints of the marathon runners, and in 18% of the controls. Conclusion. MRI shows several abnormalities in the ankle and foot both after marathon races and in asymptomatic physically active individuals without any preceding extraordinary strain. Recreational sports may lead to a number of positive MRI findings without correlation with clinical findings.

Acute paediatric ankle trauma: MRI versus plain radiography

Abstract.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.

MR findings in humeral epicondylitis. A systematic review.

Purpose: To highlight the importance of meta-analysis in diagnostic imaging by presenting a systematic search of the literature on the accuracy of MR imaging in epicondylitis. Material and Methods: The literature was comprehensively reviewed to identify studies on MR findings in epicondylitis. Reviewers blind to the clinical diagnoses screened the data according to predetermined inclusion criteria. Data were collected and validity and relevance were assessed on structured forms. Results: Seven studies including 148 patients with epicondylitis were accepted for the analysis. Eleven asymptomatic contralateral elbows and 29 elbows of healthy volunteers served as controls. The volunteers were distinctly younger than the patients. The MR technique was divergent, and the observed pathological changes also varied. The most frequent alteration was a change in the common extensor tendon signal (90%, 95% confidence interval 84-94%); 14% of the healthy volunteers and 50% of the contralateral elbows displayed the similar alteration. Conclusion: Small sample size and methodological shortcomings in the original studies make the assessment of MR findings in epicondylitis questionable. There is a need for well-designed studies in which clinical features and occupational backgrounds as well as imaging parameters are carefully documented.

Total knee arthroplasty in patients with diastrophic dysplasia.

BACKGROUND Diastrophic dysplasia results in severe disproportionate short stature, generalized joint deformities, and early osteoarthritis. The knee joint often has an abnormal valgus position and is unstable, and degeneration of all joint compartments occurs, even during growth. The purpose of our study was to evaluate the clinical and radiographic results of total knee arthroplasty in a series of patients with diastrophic dysplasia. METHODS Between February 1992 and March 2000, twenty-one primary total knee arthroplasties were performed on fourteen consecutive patients with severe osteoarthritis due to diastrophic dysplasia. The patients were followed prospectively with clinical examinations, determination of the Hungerford knee scores, and radiographs. Preoperatively, ten knees had chronic dislocation of the patella. The mean duration of follow-up was 3.4 years. RESULTS The mean Hungerford knee pain and total scores improved from 5.8 points and 46 points preoperatively to 50 points and 83 points, respectively, at the final follow-up examination (p < 0.001 for both comparisons). Two knees required a distal femoral corrective osteotomy because of metaphyseal angulation. None of the total knee arthroplasties had to be revised during the follow-up period. Six complications were recorded. CONCLUSIONS Total knee arthroplasty substantially improved the function of patients with diastrophic dysplasia. Additional peripatellar procedures were commonly needed, and complications were frequent.

MRI in the assessment of growth arrest.

Objective: To compare MRI with X-ray tomography in the assessment of bone bridges across the growth plate. Materials and methods: The investigation consisted of two parts. (1) Eleven children with 13 epiphyses suspected of physeal growth arrests were examined with conventional X-ray tomography and MRI. The bar was post-traumatic in eight children, postinfectious in two and due to a congenital, operated pes equinovarus in one. Three blinded radiologists separately evaluated the examinations retrospectively. (2) The images of four children with known physeal bars in the ankle were mixed with 36 normal examinations obtained 1-year after trauma and evaluated blindly by three radiologists. Results: In 5 of 13 epiphysis, the bony bridge was considered smaller on MRI than on X-ray tomography, in 7 of 13 it was considered equal, while it was larger only in one. The interobserver agreement (weighted kappa) was 0.8 (very good) for MRI, 0.76 (good) for X-ray tomography and 0.60 (moderate) for radiographs. The four bony bridges were easily detected on MRI. Conclusions: Compared to MRI, the size of bridges was estimated larger by tomography in about half of the patients.

MR Imaging in Suspected Acute Trauma of Wrist Bones

Objective: the purpose of this study was to evaluate the findings of MR imaging compared to plain radiography in acute wrist trauma. Methods: Radiography and MR imaging (obtained at 1.5 T) of 67 patients (38 female, 29 male, aged 15–80 years) were analysed by three senior radiologists in a blinded random fashion. Results: One-third (n=13) of the 37 fractures observed on MR images were missed on the radiographs. the McNemar test indicated significant differences in diagnoses between radiography and MR. Conclusion: We recommend that MR imaging should be considered in the diagnosis of acute wrist trauma when: 1) There is a clear discrepancy between the clinical status and a negative radiography and when splint treatment would increase cost by causing occupational restrictions; and 2) Healing of trauma diagnosed as contusion or distension does not occur within the expected time.

Changing from analog to digital images: Does it affect the accuracy of alignment measurements of the lower extremity?

Background and purpose Medical imaging has changed from analog films to digital media. We examined and compared the accuracy of orthopedic measurements using different media. Methods Before knee arthroplasty, full-length standing radiographs of 52 legs were obtained. The mechanical axis (MA), tibio-femoral angle (TFA), and femur angle (FA) were measured and analyzed twice, by 2 radiologists, using (1) true-size films, (2) short films, (3) a digital high-resolution workstation, and (4) a web-based personal computer. The agreement between the 4 media was evaluated using the Bland-Altman method (limits of agreement) using the true-size films as a reference standard. Results The mean differences in measurements between the traditional true-size films and the 3 other methods were small: for MA –0.20 to 0.07 degrees, and for TFA –0.02 to 0.18 degrees. Also, the limits of agreement between the traditional true-size films and the three other methods were small. Interpretation The agreement of the alignment measurements across the 4 different media was good. Orthopedic angles can be measured as accurately from analog films as from digital screens, regardless of film or monitor size.

Childhood femoral fracture can lead to premature knee-joint arthritis. 21-year follow-up results: a retrospective study.

Background and purpose During the past decades, treatment of pediatric femoral fractures in Finland has changed from mostly non-operative to more operative. In this retrospective study, we analyzed the long-term results of treatment. Patients and methods 74 patients (mean age 7 (0–14) years) with a femoral fracture were treated in Aurora City Hospital in Helsinki during the period 1980–89. 52 of 74 patients participated in this clinical study with a mean follow-up of 21 (16–28) years. Fracture location, treatment mode, time of hospitalization, and fracture alignment at union were assessed. Subjective assessment and range of motion of the hip and knee were evaluated. Leg-length discrepancy and alignment of the lower extremities were measured both clinically and radiographically. Results Of the 52 children, 28 had sustained a shaft fracture, 13 a proximal fracture, and 11 a distal fracture. 44 children were treated with traction, 5 by internal fixation, and 3 with cast-immobilization. Length of the hospital treatment averaged 58 (3–156) days and the median traction time was 39 (3–77) days. 21 of the 52 patients had angular malalignment of more than 10 degrees at union. 20 patients experienced back pain. Limping was seen in 10 patients and leg-length discrepancy of more than 15 mm was in 8 of the 52 patients. There was a positive correlation between angular deformity and knee-joint arthritis in radiographs at follow-up in 6 of 15 patients who were over 10 years of age at the time of injury. Interpretation Angular malalignment after treatment of femoral fracture may lead to premature knee-joint arthritis. Tibial traction is not an acceptable treatment method for femoral fractures in children over 10 years of age.

MR Imaging in Biofix-Osteosynthesis

Purpose: Osteosynthesis by means of bioresorbable implants, mostly of self-reinforced poly-L-lactide (SR-PLLA), has been used in humans for about 10 years. The aim of this study was to examine the controversy between histological studies confirming fragmentation of the biomaterial and radiological studies showing no breaking of the material. Material and Methods: Six patients with displaced malleolar fractures operatively treated with biodegradable SR-PLLA screws underwent MR examinations at 1.5 T, immediately postoperatively and after one to two years. Results: The biodegradable osteosynthetic screws were clearly seen on all MR images. Of 12 screws, 6 were broken at the final examination (5 syndesmotic transfixation screws and 1 screw through the growth cartilage). Conclusion: The breaking of a biodegradable osteosynthesis is possible to document on MR images.