MRI characteristics of nodular fasciitis of the musculoskeletal system.

OBJECTIVE: To evaluate MRI imaging appearances of nodular fasciitis in a pathologic-proven series of 29 patients. MATERIALS AND METHODS: Review of the orthopedic oncology and pathology databases yielded 51 cases of histologically proven nodular fasciitis. MR imaging was available in 29 patients. Three musculoskeletal radiologists retrospectively reviewed all cases in consensus. Imaging features evaluated included location in the body, size, compartmental localization, relationship to fascia, signal characteristics, enhancement pattern, transcompartmental extension, and osseous and intra-articular involvement. RESULTS: There were 15 male and 14 female patients. Mean age was 33 years (range, 16-59 years). Lesions ranged in size from 1.6 to 9 cm with 84 % of lesions measuring less than 4 cm. Twenty-three lesions were located in the upper arm or shoulder girdle. Nine lesions were subcutaneous in location, nine were intra-muscular, and 11 were inter-muscular. Lesions were consistently ovoid in shape with broad fascial contact. They exhibited internal homogenous low T1 and heterogeneous intermediate T2 signal with surrounding edema and slightly inhomogeneous enhancement. Twelve lesions exhibited central non-enhancing areas. Trans-compartmental spread was demonstrated in nine lesions. Osseous changes were seen in five cases and included extrinsic cortical saucerization, medullary edema, and transcortical osseous invasion. Two lesions demonstrated intra-articular extension. CONCLUSIONS: MR imaging features of nodular fasciitis are generally non-specific and can be mistaken for a soft tissue sarcoma. This series, the largest MRI series of musculoskeletal cases in the literature, confirms the predilection of nodular fasciitis for the upper extremity in young adults but also demonstrates that aggressive imaging features such as transcompartmental spread, and osseous and intra-articular involvement may be seen in association with this benign soft tissue lesion.

Serum non-coding RNAs as biomarkers for osteoarthritis progression after ACL injury.

OBJECTIVE: The aim of this study was to examine serum non-coding RNAs as potential biomarkers for cartilage damage associated with anterior cruciate ligament (ACL) injury. METHODS: Serum was obtained from 80 patients 1 year after surgery for ACL injury and 60 normal donors without overt skeletal injury. Total serum RNA was isolated, small non-coding RNAs profiled by TaqMan array MicroRNA (miRNA) analysis and individual small RNA assays performed by quantitative TaqMan RT-PCR (qPCR). Semi-quantitative magnetic resonance imaging (MRI) analysis was performed using Whole Organ Magnetic Resonance Knee Score (WORMS) scoring for analysis of cartilage damage. RESULTS: Initial TaqMan array miRNA profiling showed an increased serum concentration of a small nucleolar RNA (snoRNA), U48, in five patients with cartilage damage compared with that in five patients without cartilage damage and six normal donors. Independent qPCR analysis of snoRNAs in serum from all patients and normal donors showed a strong association between the serum level of another snoRNA, U38, and cartilage damage in ACL injury patients and together with snoRNA, U48, clear distinction between ACL injury patients and normal donors. CONCLUSION: SnoRNAs U38 and U48 are significantly elevated in the serum of patients developing cartilage damage at 1 year after ACL injury. Serum levels of U38 have the potential to facilitate early diagnosis of patients with cartilage damage after ACL injury. This study suggests serum non-coding RNAs may serve as novel noninvasive biomarkers for the detection and assessment of cartilage damage after ACL injury.

Multimodal approach in the use of clinical scoring, morphological MRI and biochemical T2-mapping and diffusion-weighted imaging in their ability to assess differences between cartilage repair tissue after microfracture therapy and matrix-associated autologous chondrocyte transplantation: a pilot study.

OBJECTIVE: The aim of the present pilot study is to show initial results of a multimodal approach using clinical scoring, morphological magnetic resonance imaging (MRI) and biochemical T2-relaxation and diffusion-weighted imaging (DWI) in their ability to assess differences between cartilage repair tissue after microfracture therapy (MFX) and matrix-associated autologous chondrocyte transplantation (MACT). METHOD: Twenty patients were cross-sectionally evaluated at different post-operative intervals from 12 to 63 months after MFX and 12-59 months after MACT. The two groups were matched by age (MFX: 36.0+/-10.4 years; MACT: 35.1+/-7.7 years) and post-operative interval (MFX: 32.6+/-16.7 months; MACT: 31.7+/-18.3 months). After clinical evaluation using the Lysholm score, 3T-MRI was performed obtaining the MR observation of cartilage repair tissue (MOCART) score as well as T2-mapping and DWI for multi-parametric MRI. Quantitative T2-relaxation was achieved using a multi-echo spin-echo sequence; semi-quantitative diffusion-quotient (signal intensity without diffusion-weighting divided by signal intensity with diffusion weighting) was prepared by a partially balanced, steady-state gradient-echo pulse sequence. RESULTS: No differences in Lysholm (P=0.420) or MOCART (P=0.209) score were observed between MFX and MACT. T2-mapping showed lower T2 values after MFX compared to MACT (P=0.039). DWI distinguished between healthy cartilage and cartilage repair tissue in both procedures (MFX: P=0.001; MACT: P=0.007). Correlations were found between the Lysholm and the MOCART score (Pearson: 0.484; P=0.031), between the Lysholm score and DWI (Pearson:-0.557; P=0.011) and a trend between the Lysholm score and T2 (Person: 0.304; P=0.193). CONCLUSION: Using T2-mapping and DWI, additional information could be gained compared to clinical scoring or morphological MRI. In combination clinical, MR-morphological and MR-biochemical parameters can be seen as a promising multimodal tool in the follow-up of cartilage repair.

Quantitative MR imaging evaluation of the cartilage thickness and subchondral bone area in patients with ACL-reconstructions 7 years after surgery.

OBJECTIVE: To evaluate the cartilage thickness (ThC) and subchondral bone area (tAB) of the operated and contra-lateral non-operated (healthy) knees in patients with anterior cruciate ligament (ACL)-reconstruction 7 years after surgery using a quantitative and regional cartilage MR imaging (qMRI) technique. METHODS: Charts of 410 patients with ACL-reconstructions were retrospectively reviewed. Fifty-two patients (male/female, 28/24; mean age, 33.3 years) were included. Patients underwent KT-1000 testing and qMRI of both knees using coronal fat-saturated 3D spoiled gradient-recalled echo (SPGR) sequences (TR/TE, 44/4 ms) at 1.5 T. Quantitative analyses of ThC and tAB in the femoro-tibial cartilage plates were performed using a subregional approach. In addition, qualitative and quantitative assessment of femoral condyle shapes was performed. t tests with Bonferroni corrections were used for statistical analysis of side-to-side differences between the operated and non-operated knees. RESULTS: KT-1000 testing was abnormal in 3/52 patients (6%). Lateral femoral tAB was significantly lower (-9.2%), and medial tibial tAB was significantly larger (+2%) in the operated vs non-operated knee (P<0.001). Regional and subregional ThC side-to-side differences were less than 0.1mm and, except for the external lateral femoral subregion, they were not statistically significant. Flattened and broader shapes of medial femoral condyles (P<0.001) were found in operated knees. No significant association of presence of cartilage or meniscus lesions at surgery with ThC 7 years post-operatively was found (P=0.06-0.98). CONCLUSION: There is evidence for changes in the tAB and femoral shape 7 years post-ACL-reconstruction, but no side-to-side differences in subregional ThC were found between the operated and contra-lateral non-operated knees.

Effect of zoledronate on bone quality in the treatment of aseptic loosening of hip arthroplasty in the dog.

Periprosthetic bone loss, which is a direct cause of aseptic loosening in total hip arthroplasty (THA), can be suppressed by bisphosphonates. It is unknown how the quality of this bone is affected in the presence of both wear debris (from implant) and bisphosphonates. The objective of this study was to evaluate the effect of zoledronate (ZLN) on bone quality in the presence of wear debris [polyethylene (PE) particles] in a canine model of uncemented THA. Thirty dogs underwent THA, and aseptic loosening was induced via implantation of PE particles packed into the femoral component. For 26 weeks until sacrifice, two groups (each n = 10) received weekly injections of ZLN (low dose 2 mug/kg, high dose 10 mug/kg) and the third group (control) received saline. Histological and radiographic examinations were performed to evaluate the degree of implant reaction. Histomorphometry (static/dynamic) was performed to evaluate bone turnover. Back-scattered electron imaging was used to quantify the newly formed bone and to evaluate the mineralization distribution. Density fractionation and X-ray diffraction were used to evaluate mineral properties, while four-point bending was used to determine mechanical properties. A dose-dependent presence of newly formed subperiosteal bone was found, which appeared to be less mineralized than the adjacent cortical bone. The high-dose ZLN group showed decreased cortical porosity and turnover and increased mineralization profile, failure strength, and modulus. We conclude that ZLN affects some of the material properties of cortical bone and allows the newly formed subperiosteal bone to remain and therefore affect the overall quality of the bone.

Transarticular invasion of bone tumours across the sacroiliac joint.

PURPOSE: The purpose of this study was to evaluate the pattern of tumour spread across the SI articulation, correlating with cadaveric anatomic observations, in order to better understand the local spread of tumour and to assist in the assessment of local staging. MATERIAL AND METHODS: Twenty-four consecutive patients (14 male, 10 female; age range 22-89 years, mean 52 years) with primary bone tumours of the iliac bone or sacrum abutting the SI joint, in whom surgical resection of the SI joint was performed, were studied following institutional ethics approval. In all patients, preoperative magnetic resonance (MR) imaging studies of the pelvis and SI joint were reviewed for imaging evidence of transarticular extension across the SI joint. Gross pathologic and histologic assessment of possible transarticular SI joint tumour extension was performed in all patients. Nine cadaveric pelvic specimens without pelvic neoplastic disease (4 male, 5 female; age range 20-84 years, mean 59 years, median 58 years) were anatomically dissected and the articular anatomy of the SI joint examined macroscopically. RESULTS: Twelve of the twenty-four patients demonstrated imaging and histological evidence of transarticular SI joint invasion. Eight tumours infiltrated only the interosseous ligamentous aspect of the SI joint. In the remaining four cases, extensive tumour infiltrated both the cartilaginous and ligamentous aspects of the joint. No case showed tumour involvement isolated to the cartilaginous aspect of the joint. Among the cadaveric specimens studied, degenerative changes were found involving the majority of cases (6/9), with cartilage thinning and fibrillation and antero-superior marginal osteophytes seen involving the cartilaginous portion of the SI joint articulation. Four of the nine specimens demonstrated central ossification bridging the iliac and sacral aspects of the ligamentous (interosseous) SI joint. CONCLUSION: Tumour invasion across the SI articulation favours its interosseous ligamentous portion. Factors influencing transarticular tumour extension and its preferential course across the interosseous component of the articulation have been discussed. It is particularly important to assess the interosseous ligamentous portion of the SI articulation when locally staging primary pelvic bone tumours subjacent to the SI articulation, as this will have a significant impact on planning surgical management.

Imaging of patellofemoral disorders.

Anterior knee pain is a common symptom, which may have a large variety of causes including patellofemoral pathologies. Patellofemoral maltracking refers to dynamic abnormality of patellofemoral alignment and has been measured using plain film, computed tomography (CT) and magnetic resonance imaging (MRI) using static and kinematic techniques. Patellar dislocation is usually transient, but specific conventional radiographic and MRI features may provide evidence of prior acute or chronic dislocation. In addition, chondromalacia patellae, osteochondritis dissecans, patellofemoral osteoarthritis, excessive lateral pressure syndrome, and bipartite patella have all been implicated in causing patellofemoral pain. The imaging and clinical features of these processes are reviewed, highlighting the specific diagnostic features of each condition.

Anteromedial impingement of the ankle: using MR arthrography to assess the anteromedial recess.

OBJECTIVE: Our objective was to describe the appearance of the anteromedial tibiotalar joint on MR arthrography in patients with clinically and arthroscopically confirmed anteromedial impingement. CONCLUSION: Anteromedial impingement of the ankle is now being recognized in the orthopedic literature as a distinct entity. MR arthrographic findings of anteromedial impingement include capsular and synovial soft-tissue thickening anterior to the tibiotalar ligaments and any associated osseous abnormality. Although anteromedial impingement is uncommon compared with other impingement syndromes of the ankle, the radiologist should be aware of the diagnosis and possible findings on cross-sectional imaging.

Periosteal chondroid tumors: radiologic evaluation with pathologic correlation.

OBJECTIVE: The purpose of this study was to determine whether the imaging features of periosteal chondroid tumors correlate with histopathology. MATERIALS AND METHODS: Twenty-two patients (nine women and 13 men; mean age, 33 years) with pathologically proven periosteal chondroid lesions were retrospectively reviewed. The imaging modalities included conventional radiography (n = 17), CT (n = 10), and MR imaging (n = 14). The images were reviewed by two osteoradiologists, with agreement by consensus. Evaluation criteria included lesion location, mineralization, and size; periosteal reaction; and cortical response. Intramedullary extension, adjacent intramedullary edema, soft-tissue edema, and intrinsic characteristics were also evaluated on MR imaging. After the evaluation, a radiologic diagnosis of chondroma or chondrosarcoma was obtained. An experienced osteopathologist who was unaware of the patient's medical history and radiologic findings reviewed all histopathology. Agreement between the radiologic and the histopathologic diagnosis was tested using the kappa analysis. Imaging features were correlated with the pathologic findings, and a statistical analysis was performed. RESULTS: Using strict pathologic criteria, we diagnosed 11 chondromas and 11 chondrosarcomas (nine, grade I; two, grade II). Moderate agreement was reached between the radiologic and the pathologic diagnosis (kappa = 0.55). The size of periosteal chondrosarcomas (range, 3-14 cm; median, 4 cm) was considerably larger than the size of the chondromas (range, 1-6.5 cm; median, 2.5 cm; p < 0.05). Other imaging features did not significantly correlate with benign versus malignant disease at pathology (all p > 0.05). CONCLUSION: A variable overlap existed in the imaging appearances of benign and malignant periosteal chondroid lesions, with size being the most reliable indicator in distinguishing the two lesions. This and the fact that histologic differentiation of the entities can be difficult, suggests that surgical wide excision may be the most appropriate procedure in treating patients with lesions greater than 3 cm.

Anterolateral ankle impingement: mr arthrographic assessment of the anterolateral recess.

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in assessing the anterolateral recess of the ankle. MATERIALS AND METHODS: Thirty-two patients with chronic ankle pain prospectively underwent gadolinium-enhanced MR arthrography of the tibiotalar joint. All underwent clinical examination and were included if anterolateral impingement (n = 13) or a control condition (n = 19; suspected osteochondral defect, intraarticular bodies, instability, osteoarthritis) was diagnosed. MR imaging included transverse and coronal T1-weighted and sagittal T2-weighted imaging sequences. Images were prospectively analyzed by two readers blinded to the clinical diagnosis. The anterolateral gutter contour was assessed. MR arthrographic findings were correlated with subsequent arthroscopic appearances. RESULTS: MR arthrographic assessment of the anterolateral soft tissues had an accuracy of 97%, sensitivity of 96%, specificity of 100%, negative predictive value of 89%, and positive predictive value of 100%. Accuracy was 100% with clinical anterolateral impingement, with an arthroscopically confirmed abnormality in 12 cases and a normal appearance in one. Anterolateral soft-tissue thickening was identified at MR arthrography in 11 control cases, with arthroscopic confirmation in all. The remaining cases had normal appearances, with an arthroscopic soft-tissue abnormality in one case and a normal appearance in seven. CONCLUSION: MR arthrography of the tibiotalar joint is accurate in assessing the anterolateral recess of the ankle.

Osteoid-producing tumors of bone.

Osteoid-producing skeletal tumors are commonly encountered lesions by radiologists. Lesions include both benign tumors--osteoma, enostosis, osteoid osteoma, and osteoblastoma--as well as the malignant neoplasm, osteosarcoma. Radiologic features of these lesions are emphasized in this article and are frequently diagnostic. In addition, clinical characteristics, treatment, and prognosis are reviewed.

Unsuspected metastases presenting as solitary soft tissue lesions: a fourteen-year review.

OBJECTIVE: To describe a series of patients with no known primary malignancy who presented with a solitary unsuspected soft tissue metastasis masquerading as a soft tissue sarcoma, and secondarily to describe the imaging appearance of these lesions. DESIGN: Records of two academic hospitals with active orthopedic oncology services were reviewed for patients meeting the above criteria. Clinical charts were examined, and the imaging appearance of the soft tissue lesions retrospectively reviewed. PATIENTS: Of 1421 patients examined for soft tissue lesions, 11 were found who met the above criteria. RESULTS: Of the 11 patients whose initial presentation was a solitary soft tissue metastasis, eight were found to have a primary lung cancer, two were diagnosed with adenocarcinoma of unknown primary, and adenocarcinoma of the colon was discovered in the remaining patient. CONCLUSIONS: The clinical presentation of a solitary soft tissue metastasis without a known primary malignancy is a rare occurrence, with an incidence of approximately 0.8%. Lung cancer is the primary neoplasm in a high percentage of these cases.

Periprosthetic bone remodelling around a prosthesis for distal femoral tumours. Measurement by dual-energy X-ray absorptiometry (DEXA).

We used dual-energy x-ray absorptiometry (DEXA) to evaluate the extent of periprosthetic bone remodelling around a prosthesis for distal femoral reconstruction, the Kotz modular femoral tibial replacement (KMFTR; Howmedica, Rutherford, New Jersey). A total of 23 patients was entered into the study which had four parts: 1) 17 patients were scanned three times on both the implant and contralateral legs to determine whether the precision of DEXA measurements was adequate to estimate bone loss surrounding the anchorage piece of the KMFTR; 2) in 23 patients the bone mineral density (BMD) in different regions of interest surrounding the diaphyseal anchorage was compared with that of the contralateral femur at the same location to test whether there was consistent evidence of loss of BMD adjacent to the prosthetic stem; 3) in 12 patients sequential studies were performed about one year apart to compare bone loss; and 4) bone loss was compared in ten patients with implants fixed by three screws and in 13 without screws. The mean coefficients of variation (SD/mean) for the 17 sets of repeated scans ranged from 2.9% to 7.8% at different regions of interest in the KMFTR leg and from 1.4% to 2.5% in the contralateral leg. BMD was decreased in the KMFTR leg relative to the contralateral limb and the percentage of BMD loss in general increased as the region of interest moved distally in the femur. Studies done after one year showed no consistent pattern of progressive bone loss between the two measurements. The ten patients with implants fixed by screws were found to have a mean loss of BMD of 42% in the most distal part of the femur, while the 13 without screw fixation had a mean loss of 11%. DEXA was shown to have adequate precision to evaluate loss of BMD around the KMFTR. This was evident relative to the contralateral leg in all patients and generally increased in the most distal part of the femur. In general, it stabilised between two measurements taken one year apart and was greater surrounding implants fixed by cross-locking screws.

Ultrasonographic prediction of fetal macrosomia. Association with cesarean delivery.

OBJECTIVE: To investigate whether the incorrect ultrasonographic prediction of macrosomia affects the cesarean delivery rate among nonmacrosomic neonates. STUDY DESIGN: For this retrospective, cohort study, comprehensive ultrasonographic records were reviewed at two centers. Patients with singleton, nonanomalous gestations whose ultrasonography predicted an estimated fetal weight > or = 4,000 g composed one cohort (n = 135), while the other cohort (n = 129) consisted of patients whose ultrasonography predicted an estimated fetal weight between 3,000 and 3,999 g. We compared the cesarean delivery rate in neonates falsely diagnosed with macrosomia (false positives) with the rate in those correctly diagnosed as nonmacrosomic (true negatives). RESULTS: The rate of cesarean delivery was significantly higher among those falsely diagnosed by ultrasonography with a macrosomic fetus as compared to those with a fetus truly diagnosed as nonmacrosomic (42.3% vs. 24.3%, relative risk = 1.74, 95% confidence interval 1.09-2.78). Subgroup analyses excluding diabetic mothers and multiparous women and comparing false positives with true negatives with neonatal birth weights between 3,500 and 4,000 g (birth weights similar to false positives) demonstrated significantly increased cesarean delivery rates among false positives. CONCLUSION: Even in nonmacrosomic neonates, the antenatal ultrasonographic diagnosis of suspected macrosomia is associated with a significant increase in cesarean delivery rates.