Leon D. Rybak

Quantitative magnetic resonance imaging evidence of synovial proliferation is associated with radiographic severity of knee osteoarthritis.

OBJECTIVE To evaluate the relationships between both quantitative and semiquantitative assessments of the degree of knee synovitis on 3T magnetic resonance imaging (MRI) and the severity of knee osteoarthritis (OA) on radiography. METHODS Fifty-eight patients with knee OA underwent nonfluoroscopic fixed-flexion knee radiography. In addition, dynamic contrast-enhanced 3T MRI of the knees was performed, before and after gadolinium administration, to quantify synovial membrane volume (SV) as a measure of synovial proliferation (expressed as the quantitative SV), and semiquantitative measures of synovitis were also applied using both contrast-enhanced and unenhanced images. Two radiologists scored the knee radiographs using the Osteoarthritis Research Society International atlas; interreader agreement was assessed using kappa statistics and concordance correlation coefficients. Multiple linear and logistic regression analyses were used to assess associations among variables, while controlling for the effects of age, body mass index, sex, and meniscal extrusion. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for measures of disease activity. RESULTS The Kellgren/Lawrence (K/L) grade of radiographic knee OA severity (β=0.78), the diseased compartment joint space width (dcJSW) (β=-0.22), and the diseased compartment joint space narrowing (dcJSN) score (β=0.53) were each significantly associated with the quantitative SV (P=0.0001, P=0.0003, and P=0.0001, respectively). Furthermore, the quantitative SV strongly correlated with the total volume of subchondral bone marrow lesions (BMLs) (β=0.22, P=0.0003). The K/L grade, dcJSW, and dcJSN score were each significantly associated with the semiquantitative Boston Leeds Osteoarthritis Knee Score (BLOKS) for the extent of infrapatellar synovitis (OR 9.05 [95% CI 1.94, 42.3] for K/L grade; OR 0.75 [95% CI 0.54, 1.03] for dcJSW; and OR 2.22 [95% CI 1.15, 4.31] for dcJSN score) and extent of joint effusion (OR 5.75 [95% CI 1.23, 26.8] for K/L grade; OR 0.70 [95% CI 0.50, 0.98] for dcJSW; and OR 1.96 [95% CI 1.02, 3.74] for dcJSN score). In addition, the semiquantitative synovitis grade on contrast-enhanced MRI was significantly associated with the K/L grade (β=0.036, P=0.0040) and dcJSN score (β=0.015, P=0.0266), and also significantly associated with the BLOKS synovitis score. CONCLUSION Synovitis is a characteristic feature of advancing knee OA and is significantly associated with the K/L grade, JSW, JSN score, and total volume of BMLs on radiographs. Furthermore, BLOKS scoring of synovitis on unenhanced MRI is associated with measurements of synovitis on contrast-enhanced MRI.

Thermal Ablation of Spinal Osteoid Osteomas Close to Neural Elements: Technical Considerations

OBJECTIVE The purpose of this study was to evaluate experience with and determine the efficacy and safety of thermal ablation in the management of spinal osteoid osteomas close to neural elements. MATERIALS AND METHODS The records of all patients with osteoid osteomas of the spine managed with thermal ablation at two academic centers from 1993 to 2008 were reviewed. RESULTS Seventeen patients (13 male patients, four female patients; mean age, 25.9 years) had lesions in the lumbar (seven patients), thoracic (six patients), cervical (three patients), and sacral (one patient) regions of the spine. Two lesions were in the vertebral body, one was within the dens, and the others were in the posterior elements. The mean lesion diameter was 8.8 mm, and the mean distance between the lesion and the closest neural element was 4.3 mm. The lesions were managed with laser (13 lesions) or radiofrequency (four lesions) ablation. Special thermal protection techniques involving the epidural injection of gas or cooled fluid were used. Pain levels were assessed immediately before the procedure and on the day after the procedure. Long-term follow-up findings were available for 11 patients. No complications were encountered, and all patients reported relief of pain. The 11 patients who participated in long-term follow-up reported continued relief of pain. CONCLUSION Percutaneous thermal ablation can be used to manage spinal osteoid osteomas close to the neural elements. Special thermal protection techniques may add a margin of safety.

Chondroblastoma: Radiofrequency Ablation—Alternative to Surgical Resection in Selected Cases

PURPOSE To demonstrate that radiofrequency (RF) ablation can be used safely and effectively to treat selected cases of chondroblastoma. MATERIALS AND METHODS Approval was obtained from institutional review boards, research was in compliance with HIPAA protocol. The need to obtain informed consent was waived for retrospective review of patient records. The records of patients with biopsy-proved chondroblastoma who were treated with RF ablation at two academic centers from July 1995 to July 2007 were reviewed. RF ablation was performed with a single-tip electrode by using computed tomography for guidance. Lesion characteristics were determined from imaging studies obtained at the time of the procedure. Symptoms were assessed before and 1 day after the procedure. Longer-term follow-up was obtained from medical records. RESULTS Thirteen male and four female patients were treated (mean age, 17.3 years). The lesions were located in the proximal humerus (n = 7), proximal tibia (n = 4), proximal femur (n = 3), and distal femur (n = 3). The mean volume of the lesions was 2.46 mL. All patients reported relief of symptoms on postprocedure day 1. Three patients were lost to follow-up. Of the 14 patients for whom longer-term (mean, 41.3 months; range, 4-134 months) follow-up was available, 12 had complete relief of symptoms with no need for medications and full return to all activities. The patient who had the largest lesion of the study required surgical intervention because of collapse of the articular surface in the treatment area. Residual viable tumor was found at surgery. Another patient experienced mechanical problems that were thought to be unrelated to the RF ablation and was rendered pain-free after subsequent surgical treatment. CONCLUSION Percutaneous RF ablation is an alternative to surgery for treatment of selected chondroblastomas. Larger lesions beneath weight-bearing surfaces should be approached with caution due to an increased risk of articular collapse and recurrence.

Primary Rosai-Dorfman disease of bone: a clinicopathologic study of 15 cases.

Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disorder of unknown etiology. Most patients present with lymph node involvement manifesting as adenopathy; however, RDD may arise primarily in a variety of extranodal sites, including bone. We report herein our experience with 15 cases of primary intraosseous RDD. The patients include 8 females and 7 males, who ranged in age from 3 to 56 (mean 27) years. The lesions arose in a variety of anatomical locations, including the tibia, femur, clavicle, skull, maxilla, calcaneus, phalanx, metacarpal, and sacrum. Radiographically, the lesions were lytic with well defined and usually sclerotic margins. Histologically, the lesions demonstrated the classic features of RDD and consisted of a mixed inflammatory infiltrate with numerous large histiocytes with abundant eosinophilic cytoplasm which exhibited emperipolesis. Some cases also contained numerous neutrophils. Immunohistochemical stains showed that the large histiocytes were S-100 positive. Follow-up information was available for 12 patients. Five patients eventually developed additional extraosseous manifestations, including testicular, lymph node, and subcutaneous lesions. One of these 5 also developed a new bony lesion within the sternum. One patient developed additional lesions within multiple bones of the hand and wrist, without extraosseous disease. One patient had stable bony lesions, whereas 5 remained disease free after treatment.

The lumbar facet joint: a review of current knowledge: part 1: anatomy, biomechanics, and grading

We present a two-part review article on the current state of knowledge of lumbar facet joint pathology. This first article discusses the functional anatomy, biomechanics, and radiological grading systems currently in use in clinical practice and academic medicine. Facet joint degeneration is presented within the larger context of degenerative disc disease to enable the reader to better understand the anatomical changes underlying facet-mediated lower back pain. Other less-common, but equally important etiologies of lumbar facet joint degeneration are reviewed. The existing grading systems are discussed with specific reference to the reliability of CT and MR imaging in the diagnosis of lumbar facet osteoarthritis. It is hoped that this discussion will stimulate debate on how best to improve the diagnostic reliability of these tests so as to improve both operative and non-operative treatment outcomes.

Cortico-medullary continuity in bizarre parosteal osteochondromatous proliferation mimicking osteochondroma on imaging.

Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora’s lesion, is an unusual surface-based lesion of bone found most commonly in the hands and feet. In the original description of the lesion and in all publications that followed, one of the key imaging characteristics used to define this entity was the lack of cortico-medullary continuity with the underlying bone. The authors present 4 unique cases of pathologically proven BPOP in which cortico-medullary continuity with the underlying bone was demonstrated on imaging. It is believed that florid reactive periostitis, BPOP and turret osteochondroma may reflect points along the same continuum with trauma the likely inciting event. The authors suggest that, given this continuum, it may be possible to have BPOP lesions demonstrating overlapping imaging features with osteochondroma. If this is the case, strict adherence to the standard imaging criterion of lack of continuity between the lesion and the underlying bone may lead to misdiagnosis of these unusual cases of BPOP as osteochondromas.

Bisphosphonate-Related Complete Atypical Subtrochanteric Femoral Fractures: Diagnostic Utility of Radiography

OBJECTIVE The objective of our study was to evaluate the diagnostic utility of conventional radiography for diagnosing bisphosphonate-related atypical subtrochanteric femoral fractures. MATERIALS AND METHODS Retrospective interpretation of 38 radiographs of complete subtrochanteric and diaphyseal femoral fractures in two patient groups-one group being treated with bisphosphonates (19 fractures in 17 patients) and a second group not being treated with bisphosphonates (19 fractures in 19 patients)-was performed by three radiologists. The readers assessed four imaging criteria: focal lateral cortical thickening, transverse fracture, medial femoral spike, and fracture comminution. The odds ratios and the sensitivity, specificity, and accuracy of each imaging criterion as a predictor of bisphosphonate-related fractures were calculated. Similarly, the interobserver agreement and the sensitivity, specificity, and accuracy of diagnosing bisphosphonate-related fractures (i.e., atypical femoral fractures) were determined for the three readers. RESULTS Among the candidate predictors of bisphosphonate-related fractures, focal lateral cortical thickening and transverse fracture had the highest odds ratios (76.4 and 10.1, respectively). Medial spike and comminution had odd ratios of 3.8 and 0.63, respectively. Focal lateral cortical thickening and transverse fracture were also the most accurate factors for detecting bisphosphonate-related fractures for all readers. The sensitivity, specificity, and overall accuracy for diagnosing bisphosphonate-related fractures were 94.7%, 100%, and 97.4% for reader 1; 94.7%, 68.4%, and 81.6% for reader 2; and 89.5%, 89.5%, and 89.5% for reader 3, respectively. The interobserver agreement was substantial (κ > 0.61). CONCLUSION Radiographs are reliable for distinguishing between complete femoral fractures related to bisphosphonate use and those not related to bisphosphonate use. Focal lateral cortical thickening and transverse fracture are the most dependable signs, showing high odds ratios and the highest accuracy for diagnosing these fractures.

Fire and Ice: Thermal Ablation of Musculoskeletal Tumors

Thermal ablation of tumors is a rapidly growing field that has found various applications in the musculoskeletal system. Radiofrequency ablation (RFA) has become the reference standard for treatment of most osteoid osteomas. More recently, RFA has been applied to several other forms of primary tumors and in the treatment and palliation of osseous metastases. Cryoablation using new closed systems has also become available for the percutaneous treatment of both primary and metastatic lesions, and the initial results have been promising.

Low-grade inflammation in symptomatic knee osteoarthritis: prognostic value of inflammatory plasma lipids and peripheral blood leukocyte biomarkers.

Inflammatory mediators, such as prostaglandin E2 (PGE2) and interleukin‐1β (IL‐1β), are produced by osteoarthritic (OA) joint tissue, where they may contribute to disease pathogenesis. We undertook the present study to examine whether inflammation, evidenced in plasma and peripheral blood leukocytes (PBLs), reflects the presence, progression, or specific symptoms of symptomatic knee OA.

The lumbar facet joint: a review of current knowledge: Part II: diagnosis and management

This article is the second article in a two-part review on lumbar facet joint pathology. In this review, we discuss the current concepts and controversies regarding the proper diagnosis and management of patients presenting with presumed facet-mediated lower back pain. All efforts were made to include the most relevant literature from the fields of radiology, orthopaedics, physiatry, and pain management. Our focus in this article is on presenting the evidence supporting or refuting the most commonly employed injection-based therapies for facet-mediated lower back pain.