The combination of an inflammatory peripheral blood gene expression and imaging biomarkers enhance prediction of radiographic progression in knee osteoarthritis.

OBJECTIVE: Predictive biomarkers of progression in knee osteoarthritis are sought to enable clinical trials of structure-modifying drugs. A peripheral blood leukocyte (PBL) inflammatory gene signature, MRI-based bone marrow lesions (BML) and meniscus extrusion scores, meniscal lesions, and osteophytes on X-ray each have been shown separately to predict radiographic joint space narrowing (JSN) in subjects with symptomatic knee osteoarthritis (SKOA). In these studies, we determined whether the combination of the PBL inflammatory gene expression and these imaging findings at baseline enhanced the prognostic value of either alone. METHODS: PBL inflammatory gene expression (increased mRNA for IL-1ß, TNFα, and COX-2), routine radiographs, and 3T knee MRI were assessed in two independent populations with SKOA: an NYU cohort and the Osteoarthritis Initiative (OAI). At baseline and 24 months, subjects underwent standardized fixed-flexion knee radiographs and knee MRI. Medial JSN (mJSN) was determined as the change in medial JSW. Progressors were defined by an mJSN cut-point (≥ 0.5 mm/24 months). Models were evaluated by odds ratios (OR) and area under the receiver operating characteristic curve (AUC). RESULTS: We validated our prior finding in these two independent (NYU and OAI) cohorts, individually and combined, that an inflammatory PBL inflammatory gene expression predicted radiographic progression of SKOA after adjustment for age, sex, and BMI. Similarly, the presence of baseline BML and meniscal lesions by MRI or semiquantitative osteophyte score on X-ray each predicted radiographic medial JSN at 24 months. The combination of the PBL inflammatory gene expression and medial BML increased the AUC from 0.66 (p = 0.004) to 0.75 (p < 0.0001) and the odds ratio from 6.31 to 19.10 (p < 0.0001) in the combined cohort of 473 subjects. The addition of osteophyte score to BML and PBL inflammatory gene expression further increased the predictive value of any single biomarker. A causal analysis demonstrated that the PBL inflammatory gene expression and BML independently influenced mJSN. CONCLUSION: The use of the PBL inflammatory gene expression together with imaging biomarkers as combinatorial predictive biomarkers, markedly enhances the identification of radiographic progressors. The identification of the SKOA population at risk for progression will help in the future design of disease-modifying OA drug trials and personalized medicine strategies.

Using Deep Learning to Accelerate Knee MRI at 3 T: Results of an Interchangeability Study.

OBJECTIVE. Deep learning (DL) image reconstruction has the potential to disrupt the current state of MRI by significantly decreasing the time required for MRI examinations. Our goal was to use DL to accelerate MRI to allow a 5-minute comprehensive examination of the knee without compromising image quality or diagnostic accuracy. MATERIALS AND METHODS. A DL model for image reconstruction using a variational network was optimized. The model was trained using dedicated multisequence training, in which a single reconstruction model was trained with data from multiple sequences with different contrast and orientations. After training, data from 108 patients were retrospectively undersampled in a manner that would correspond with a net 3.49-fold acceleration of fully sampled data acquisition and a 1.88-fold acceleration compared with our standard twofold accelerated parallel acquisition. An interchangeability study was performed, in which the ability of six readers to detect internal derangement of the knee was compared for clinical and DL-accelerated images. RESULTS. We found a high degree of interchangeability between standard and DL-accelerated images. In particular, results showed that interchanging the sequences would produce discordant clinical opinions no more than 4% of the time for any feature evaluated. Moreover, the accelerated sequence was judged by all six readers to have better quality than the clinical sequence. CONCLUSION. An optimized DL model allowed acceleration of knee images that performed interchangeably with standard images for detection of internal derangement of the knee. Importantly, readers preferred the quality of accelerated images to that of standard clinical images.

Vascular Adhesion Protein-1 (VAP-1) as Predictor of Radiographic Severity in Symptomatic Knee Osteoarthritis in the New York University Cohort.

BACKGROUND: To investigate the expression of vascular adhesion protein-1 (VAP-1) in joint tissues and serum in symptomatic knee osteoarthritis (SKOA) patients and examine whether VAP-1 levels predict increased risk of disease severity in a cross-sectional study. METHODS: Baseline VAP-1 expression and soluble VAP-1 (sVAP-1) levels were assessed in the synovium synovial fluid and in the serum in cohorts of patients with tibiofemoral medial knee OA and healthy subjects. Standardized fixed-flexion poster anterior knee radiographs scored for Kellgren-Lawrence (KL) grade (0-4) and medial joint space width (JSW). KL1/2 vs. KL3/4 scores defined early and advanced radiographic severity, respectively. Biochemical markers assessed in serum or synovial fluids (SF) comprised sVAP-1, interleukin 1 receptor antagonist (IL-1Ra), interleukin 6 (IL-6), soluble receptor for advanced glycation end-products (sRAGE), C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 4 (CCL4), cluster of differentiation 163 (CD163), high sensitivity C-reactive protein (hsCRP), and matrix metalloproteinases (MMPs)-1,-3,-9. Associations between biomarkers and radiographic severity KL1/2 vs. KL3/4 (logistic regression controlling for covariates) and pain (Spearman correlation) were evaluated. RESULTS: Elevated levels of sVAP-1 observed in OA synovial fluid and VAP-1 expression in synovium based on immunohistochemical, microarray, and real-time quantitative polymerase chain reaction (qRT-PCR) analyses. However, serum sVAP-1 levels in OA patients were lower than in controls and inversely correlated with pain and inflammation markers (hsCRP and soluble RAGE). Soluble VAP-1 levels in serum were also lower in radiographically advanced (KL3/4) compared with early KL1/2 knee SKOA patients. CONCLUSION: Local (synovial fluid) semicarbazide-sensitive amine oxidase (SSAO)/sVAP-1 levels were elevated in OA and correlated with radiographic severity. However, systemic (serum) sVAP-1 levels were lower in SKOA patients than normal and inversely correlated with pain and inflammation markers. Serum sVAP-1 levels were higher in early (KL1/2) compared with advanced (KL3/4) SKOA patients.

Serum Urate Levels Predict Joint Space Narrowing in Non-Gout Patients With Medial Knee Osteoarthritis.

OBJECTIVE: The pathogenesis of osteoarthritis (OA) includes both mechanical and inflammatory features. Studies have implicated synovial fluid uric acid (UA) as a potential OA biomarker, possibly reflecting chondrocyte damage. Whether serum UA levels reflect/contribute to OA is unknown. We investigated whether serum UA levels predict OA progression in a non-gout knee OA population. METHODS: Eighty-eight patients with medial knee OA (body mass index [BMI] <33 kg/m2 ) but without gout were studied. Baseline serum UA levels were measured in previously banked serum samples. At 0 and 24 months, patients underwent standardized weight-bearing fixed-flexion posteroanterior knee radiography to determine joint space width (JSW) and Kellgren/Lawrence grades. Joint space narrowing (JSN) was calculated as the change in JSW from 0 to 24 months. Twenty-seven patients underwent baseline contrast-enhanced 3T knee magnetic resonance imaging for assessment of synovial volume. RESULTS: Serum UA levels correlated with JSN values in both univariate (r = 0.40, P < 0.01) and multivariate (r = 0.28, P = 0.01) analyses. There was a significant difference in mean JSN after dichotomization at a serum UA cut point of 6.8 mg/dl, the solubility point for serum urate, even after adjustment (JSN of 0.90 mm for a serum UA ≥6.8 mg/dl and 0.31 mm for a serum UA <6.8 mg/dl; P < 0.01). Baseline serum UA levels distinguished progressors (JSN >0.2 mm) and fast progressors (JSN >0.5 mm) from nonprogressors (JSN ≤0.0 mm) in multivariate analyses (area under the receiver operating characteristic curve 0.63 [P = 0.03] and 0.62 [P = 0.05], respectively). Serum UA levels correlated with the synovial volume (r = 0.44, P < 0.01), a possible marker of JSN, although this correlation did not persist after controlling for age, sex, and BMI (r = 0.13, P = 0.56). CONCLUSION: In non-gout patients with knee OA, the serum UA level predicted future JSN and may serve as a biomarker for OA progression.

Sparse-SEMAC: rapid and improved SEMAC metal implant imaging using SPARSE-SENSE acceleration.

PURPOSE: To develop an accelerated SEMAC metal implant MRI technique (Sparse-SEMAC) with reduced scan time and improved metal distortion correction. METHODS: Sparse-SEMAC jointly exploits the inherent sparsity along the additional phase-encoding dimension and multicoil encoding capabilities to significantly accelerate data acquisition. A prototype pulse sequence with pseudorandom ky -kz undersampling and an inline image reconstruction was developed for integration in clinical studies. Three patients with hip implants were imaged using the proposed Sparse-SEMAC with eight-fold acceleration and compared with the standard-SEMAC technique used in clinical studies (three-fold GRAPPA acceleration). Measurements were performed with SEMAC-encoding steps (SES) = 15 for Sparse-SEMAC and SES = 9 for Standard-SEMAC using high spatial resolution Proton Density (PD) and lower-resolution STIR acquisitions. Two expert musculoskeletal (MSK) radiologists performed a consensus reading to score image-quality parameters. RESULTS: Sparse-SEMAC enables up to eight-fold acceleration of data acquisition that results in two-fold scan time reductions, compared with Standard-SEMAC, with improved metal artifact correction for patients with hip implants without degrading spatial resolution. CONCLUSION: The high acceleration enabled by Sparse-SEMAC would enable clinically feasible examination times with improved correction of metal distortion. Magn Reson Med 78:79-87, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

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

OBJECTIVE: Inflammatory mediators, such as prostaglandin E2 (PGE2 ) and interleukin-1ß (IL-1ß), 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. METHODS: Patients with symptomatic knee OA were enrolled in a 24-month prospective study of radiographic progression. Standardized knee radiographs were obtained at baseline and 24 months. At baseline, levels of the plasma lipids PGE2 and 15-hydroxyeicosatetraenoic acid (15-HETE) were measured, and transcriptome analysis of PBLs was performed by microarray and quantitative polymerase chain reaction. RESULTS: Baseline PGE2 synthase (PGES) levels determined by PBL microarray gene expression and plasma PGE2 levels distinguished patients with symptomatic knee OA from non-OA controls (area under the receiver operating characteristic curve [AUC] 0.87 and 0.89, respectively, P < 0.0001). Baseline plasma 15-HETE levels were significantly elevated in patients with symptomatic knee OA versus non-OA controls (P < 0.0195). In the 146 patients who completed the 24-month study, elevated baseline expression of IL-1ß, tumor necrosis factor α, and cyclooxygenase 2 (COX-2) messenger RNA in PBLs predicted higher risk of radiographic progression as evidenced by joint space narrowing (JSN). In a multivariate model, AUC point estimates of models containing COX-2 in combination with demographic traits overlapped the confidence interval of the base model in 2 of the 3 JSN outcome measures (JSN >0.0 mm, JSN >0.2 mm, and JSN >0.5 mm; AUC 0.62-0.67). CONCLUSION: The inflammatory plasma lipid biomarkers PGE2 and 15-HETE identify patients with symptomatic knee OA, and the PBL inflammatory transcriptome identifies a subset of patients with symptomatic knee OA who are at increased risk of radiographic progression. These findings may reflect low-grade inflammation in OA and may be useful as diagnostic and prognostic biomarkers in clinical development of disease-modifying OA drugs.

Labral and cartilage abnormalities in young patients with hip pain: accuracy of 3-Tesla indirect MR arthrography.

OBJECTIVE: Assess the diagnostic accuracy of 3-T indirect magnetic resonance arthrography (iMRA) for hip cartilage and labral pathology detection using arthroscopy as the reference standard and compare it to the published performance of direct magnetic resonance arthrography (dMRA). MATERIALS AND METHODS: Between 2009 and 2011, 290 patients suspected of having femoroacetabular impingement underwent iMRA. Our study group consisted of 41 of these patients (17 males, mean age 35 years; 24 females, mean age 33 years) who did not have a prior history of hip surgery and who subsequently underwent arthroscopy. Two experienced musculoskeletal radiologists separately evaluated the randomized and anonymized studies for the presence and quadrant location of labral and cartilage pathology. These recorded data were compared to arthroscopic reports. RESULTS: Forty-one patients had labral pathology, 34 patients had acetabular and 5 patients had femoral cartilage pathology at arthroscopy. Sensitivity, specificity, accuracy, negative- and positive-predictive values for labral lesion detection were respectively 98, 99, 99, 99 and 98 %; for acetabular cartilage lesion detection they were 69, 98, 89, 87 and 95 %; for femoral cartilage lesion detection they were 69, 95, 93 and 39 %. Sensitivities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum were 100.0, 95.0, NA and 85.7 %, for acetabular cartilage were NA, 58.8, NA and 39.5 % and for femoral cartilage were 50.0, 33.3, 75.0 and 75.0 %). NA indicates results not available because of the absence of findings in those quadrants. Specificities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum (95.0, 100.0, 95.1, 67.5 %), acetabular (100.0, 85.7, 92.6, 79.5 %) and femoral cartilage (100.0, 94.7, 96.2, 85.9 %). CONCLUSION: iMRA at 3 T is accurate in detecting labral pathology suggesting that it is a viable alternative to dMRA.

Imaging of Posterior Interosseous Neuropathy following Distal Biceps Repair: A Report of 3 Cases.

Three cases of PIN palsy following biceps repair are presented with clinical and imaging correlation. The imaging findings in these cases will be discussed and the orthopedic literature, as regards possible surgical approaches and technical factors believed to predispose to or prevent this complication, will be reviewed. It is important for radiologists to serve as consultants in these uncommon but sometimes devastating complications, helping to quickly and accurately recognize the imaging findings corresponding to the clinical symptoms and aiding the surgeon in diagnosis and treatment by identifying the possible causes and sites of nerve compression.

Relationship between knee alignment and T1ρ values of articular cartilage and menisci in patients with knee osteoarthritis.

OBJECTIVE: To assess the relationship between knee alignment and subregional T1ρ values of the femorotibial cartilage and menisci in patients with mild (Kellgren-Lawrence grade 1) to moderate (KL3) osteoarthritis (OA) at 3T. MATERIALS AND METHODS: 26 subjects with a clinical diagnosis of KL1-3 OA were included and subdivided into three subgroups: varus, valgus, and neutral. All subjects were evaluated on a 3T MR scanner. Mann-Whitney and Wilcoxon signed rank tests were performed to determine any statistically significant differences in subregional T1ρ values of femorotibial cartilage and menisci among the three subgroups of KL1-3 OA patients. RESULTS: Medial femoral anterior cartilage subregion in varus group had significantly higher (p<0.05) T1ρ values than all cartilage subregions in valgus group. Medial tibial central cartilage subregion had significantly higher T1ρ values (p<0.05) than lateral tibial central cartilage subregion in varus group. The posterior horn of the medial meniscus in neutral group had significantly higher T1ρ values (p<0.0029) than all meniscus subregions in valgus group. CONCLUSION: There exists some degree of association between knee alignment and subregional T1ρ values of femorotibial cartilage and menisci in patients with clinical OA.

Treatment of long bone nonunions: factors affecting healing.

PURPOSE: Nonunions of the upper and lower extremity have been associated with pain and functional deficits. Recent studies have demonstrated that healing of these nonunions is associated with pain relief and both subjective and objective functional improvement. The purpose of this study was to determine which patient and surgical factors correlated with successful healing of a nonunion following surgical intervention. METHODS: Between September 2004 and February 2008, all patients with a "long bone nonunion" presenting to our academic trauma service were enrolled in a prospective data base. Baseline functional, demographic and pain status was obtained. Follow-up was obtained at 3, 6, and 12 months following surgical intervention, with longer follow-up as possible. One hundred and thirty-four patients with a variety of fracture nonunions were operated on by four different fellowship trained trauma surgeons with experience ranging from 2 to 15 years and variable nonunion surgery loads. Patients were stratified into one of three groups: 1. Patients who healed following one surgical intervention, 2. those who healed following multiple surgical intervention, and 3. those who failed to heal (remain ununited or underwent amputation). Healing was determined radiographically and clinically. Complications were recorded. Logistic regression analysis was performed to assess the cor-relation between specific baseline and surgical characteristics and healing. RESULTS: A minimum of 1 year follow-up was available for all 134 patients. One hundred and one patients (76%) with a mean age of 50 years healed at a mean of 6 months (range, 3 to 16) after one surgery. Twenty-two patients (16%) with a mean age of 47 years, who required more than one intervention, healed their nonunions at a mean of 11 months (range, 4 to 23). Eleven patients (8%) with a mean age of 50 years failed to heal at an average of 12 months follow-up. Complication rates were 11%, 68%, and 100% respectively for those who healed following one procedure, multiple procedures, and those who never healed. Higher surgeon volume (greater than 10 cases per year) was associated with 85% increased healing rates (OR = 0.15, 0.05-0.47 CI). The presence of a postoperative complication was associated with a 9 times lower likelihood of successful union as well (OR = 9.0, 2.6-31.7 CI). Patient age, sex, BMI, initial injury mechanism, tobacco use, and initial injury characteristics did not correlate with failure to heal. CONCLUSION: Our data is similar to other studies assessing outcomes following other complex reconstructive procedures. It appears that more experienced (higher volume) reconstructive surgeons and the development of fewer postoperative complications is associated with greater success following repair of a long bone nonunion. Infection at any point during treatment is associated with failure to achieve successful union.

"Incidental" bone lesions--when to refer to the tumor specialist.

Incidental bone tumors are, by definition, asymptomatic lesions that are discovered through routine radiographs obtained for other reasons. Generally, these lesions are benign and latent, requiring no further intervention except observation. However, occasionally these radiographs will detect benign aggressive processes or even malignant lesions that do require further treatment and referral to a tumor specialist. Oftentimes, there are characteristic findings on radiographs that are pathognomonic. Knowledge of these findings can simplify the treatment algorithm for a practicing general orthopaedist. This article will describe radiographic characteristics of benign and malignant bone lesions and their typical presentations. It will then focus on the types of bone lesions that are often found incidentally by routine radiography. Specific recommendations, including recommendation for referrals to orthopaedic tumor specialists, will be noted for lesions described. Most malignant lesions will present with pain and a constellation of history and physical exam findings that will signal the patient to seek medical care; although they will be mentioned for the sake of comparison and completeness, they will not be the focus of this review.

Accuracy of detecting screw penetration of the radiocarpal joint following volar plating using plain radiographs versus computed tomography.

We compared standard and specialized plain radiographs with computed tomography (CT) for their ability to detect screw penetration of the articular surface of the distal radius in volar plating. Eight human cadaveric specimens were implanted with a fixed angle volar plate and 5 screws. Two groups were evaluated: (1) no articular screw penetration or (2) intra-articular screw penetration. Radiographs were obtained of each specimen. CT using 0.4 mm thickness slices were obtained and images were reconstructed in the sagittal and coronal planes. The radiographs and CTs were evaluated based on whether or not articular penetration occurred. The sensitivity, specificity, and accuracy of each radiographic modality were evaluated. CT was found to be much more sensitive and specific in detecting screw penetration than plain radiographs. The kappa (κ) statistic demonstrated "almost perfect interobserver agreement" based on CT readings, but only "substantial interobserver agreement based on plain radiographs." CT is more sensitive and specific and achieves a higher κ statistic than plain radiographs in detecting radiocarpal screw penetration after volar plating. CT should be used in detecting screw penetration when there is suspicion for radiocarpal joint penetration.

Preliminary study of 1.5-T MR arthrography of the shoulder with 3D isotropic intermediate-weighted turbo spin echo.

OBJECTIVE: The purpose of this study was to assess the performance of a near-isotropic 3D turbo spin-echo sequence in comparison with a standard 2D protocol and with arthroscopy in direct 1.5-T MR arthrography of the shoulder. SUBJECTS AND METHODS: Dilute gadolinium was injected into three cadaver shoulders, and 3D turbo spin-echo and 2D sequences were evaluated with respect to the signal-to-noise and contrast-to-noise ratios of key tissues. In a prospective study, the 3D intermediate-weighted fat-suppressed sequence (reformatted in three planes) was added to shoulder MR arthrography of 43 consecutively registered patients, 13 of whom later underwent arthroscopy. Two radiologists independently graded the 3D and 2D images in separate sessions to visualize normal anatomic features and to detect pathologic changes in the labrum, cartilage, cuff, and glenohumeral ligaments, assigning confidence levels to their readings. One reader repeated the readings of images of 10 patients. Reports of subsequent arthroscopy were available for 13 patients. RESULTS: The sequences performed comparably with respect to signal-to-noise and contrast-to-noise ratios in the cadavers. The 3D images suffered from mildly increased blurring, but the readers were significantly more confident in assessing the proximal biceps tendon and curved portions of the labrum and in their findings of partial tears of the articular side of the supraspinatus tendon and posterior labral tears on the 3D images. A larger number of partial-thickness cartilage defects were found on 2D images. CONCLUSION: The 3D turbo spin-echo sequence is a promising technique that can be used in shoulder arthrography with image quality and results comparable to those of traditional 2D techniques. Use of the 3D technique may result in greater anatomic detail in evaluating small obliquely oriented structures, including the curved portions of the labrum and the intraarticular portion of the biceps tendon.

Technical update on magnetic resonance imaging of the shoulder.

Improvement in both hardware and software has opened up new opportunities in magnetic resonance (MR) imaging of the shoulder. MR imaging at 3-T has become a reality, with the prospect of 7-T imaging on the horizon. The art of MR arthrography continues to improve, aided by the use of novel imaging positions. New techniques for three-dimensional imaging, the reduction of metal artifact, and biochemical imaging of cartilage hold great promise.

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.

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 (ß=0.78), the diseased compartment joint space width (dcJSW) (ß=-0.22), and the diseased compartment joint space narrowing (dcJSN) score (ß=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) (ß=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 (ß=0.036, P=0.0040) and dcJSN score (ß=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.

Primary synovial chondrosarcoma of the hip joint in a 45-year-old male: case report and literature review.

Synovial chondrosarcoma is a rare tumor, seen most commonly arising from antecedent synovial chondromatosis, the more common benign entity. The distinction between the two can be difficult on the basis of clinical, imaging, and histologic criteria. The authors report a case of pathologically proven synovial chondrosarcoma of the hip in a 45-year-old male initially treated for presumed synovial chondromatosis. The case is made more unusual by the fact that no evidence of co-existent synovial chondromatosis was noted at histology. The literature as regards synovial chondrosarcoma, both de novo and secondary cases, is reviewed.

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.