Faculty Bibliography

OBJECTIVE: Criteria for sonographic diagnosis of monosodium urate (MSU) crystal deposition have been developed, but the interreader reproducibility of this modality is not well established. We therefore assessed agreement using a systematic approach. METHODS: Fifty male subjects ages 55-85 years were recruited during primary care visits to an urban Veterans Affairs hospital, and were assessed by musculoskeletal ultrasound (US) of the knees and first metatarsophalangeal (MTP) joints to evaluate for the double contour sign and tophi as evidence of MSU crystal deposition. Images were read by 2 blinded rheumatologists trained in musculoskeletal US, and the degree of concordance was determined for individual subjects, total joints, femoral articular cartilage (FAC), and first MTP joints. Subjects were further categorized into 3 diagnostic groups: gout, asymptomatic hyperuricemia (no gout, serum uric acid [UA] >/=6.9 mg/dl), and controls (no gout, serum UA </=6.8 mg/dl), and reader concordance within these 3 groups was assessed. RESULTS: We observed almost perfect agreement between readers for 1) individual subjects (yes/no; n = 50, 100% agreement, kappa = 1.000), 2) total joints (n = 200, 99% agreement, kappa = 0.942), 3) FAC (n = 100, 99% agreement, kappa = 0.942), and 4) first MTP joints (n = 100, 99% agreement, kappa = 0.942). Furthermore, findings by side (right/left) and diagnostic group (gout, asymptomatic hyperuricemia, control) showed substantial to almost perfect concordance for all measures. MSU deposition was seen most commonly in gout patients, and deposition was also seen in some subjects with asymptomatic hyperuricemia, but in only 1 control. CONCLUSION: Musculoskeletal US is reliable for detecting MSU deposition in FAC and first MTP joints in gout and asymptomatic hyperuricemia

Early detection of cartilage degeneration in the hip may help prevent onset and progression of osteoarthritis in young patients with femoroacetabular impingement. Delayed gadolinium-enhanced MRI of cartilage is sensitive to cartilage glycosaminoglycan loss and could serve as a diagnostic tool for early cartilage degeneration. We propose a new high resolution 2D T(1) mapping saturation-recovery pulse sequence with fast spin echo readout for delayed gadolinium-enhanced magnetic resonance imaging of cartilage of the hip at 3 T. The proposed sequence was validated in a phantom and in 10 hips, using radial imaging planes, against a rigorous multipoint saturation-recovery pulse sequence with fast spin echo readout. T(1) measurements by the two pulse sequences were strongly correlated (R(2) > 0.95) and in excellent agreement (mean difference = -8.7 ms; upper and lower 95% limits of agreement = 64.5 and -81.9 ms, respectively). T(1) measurements were insensitive to B(1+) variation as large as 20%, making the proposed T(1) mapping technique suitable for 3 T. Magn Reson Med, 2011. (c) 2011 Wiley-Liss, Inc

The use of bioabsorbable cross-pin transcondylar fixation has remained a viable option for femoral fixation in anterior cruciate ligament reconstruction. Although numerous biomechanical studies have demonstrated high fixation strength and minimal slippage with use of this method of fixation, there have been increasing reports of a variety of clinical complications associated with these implants. We reviewed the literature for all complications associated with the Bio-TransFix implant and present a case report of a patient status after ACL reconstruction using Bio-TransFix cross-pin femoral fixation with iliotibial band friction syndrome from a broken cross-pin four month post-operatively.

This article focuses on the variants and imaging pitfalls in the ankle and foot

OBJECTIVE: The objective of this study was to assess the prevalence of increased signal intensity in the pronator quadratus in the general patient population. Using region-of-interest measurements, we measured the signal intensity of the pronator quadratus and of an adjacent flexor muscle. In addition, we performed independent subjective assessments of the pronator quadratus. CONCLUSION: Increased signal intensity in the pronator quadratus is a frequent normal finding of unclear etiology and is not related to disease. Familiarity with this normal phenomenon is important to avoid overdiagnosis of denervation due to anterior interosseous nerve entrapment.

Background: Determination of monosodium urate (MSU) deposition in joints by musculoskeletal ultrasound (MSK-US) could have implications for uric acid (UA) management in patients with gout and possibly asymptomatic hyperuricemia (AH). Recently, criteria for sonographic diagnosis of MSU crystal deposition have been developed, but reproducibility of readings using these criteria has not been well established. Methods: We consecutively recruited male patients ages 55-85 during primary care visits to an urban VA hospital. We assessed all patients for gout by ACR criteria, and obtained serum UA levels. Patients were divided into 3 groups: gout, AH (no gout, UA >= 6.9 mg/dL), and controls (no gout, UA <= 6.8 mg/dL). 50 patients (14 with gout, 17 with AH, and 19 controls) returned for subsequent evaluation which included MSK-US of knees and 1st metatarsalphalangeal (MTP) joints to evaluate for the double contour sign (knees) and tophi (MTPs). All images were read blindly by two observers trained in rheumatology and MSK-US. Kappa statistics were used to estimate the amount of agreement between ultrasound measures scored by the two raters. We also calculated the total percent of observations in agreement. Results: Evidence of MSU crystal deposition was found in the same 10 patients by both observers (6 gout, 3 AH, 1 control), and in 3 additional patients by one of the observers (1 gout, 2 AH). These findings were further analyzed by site. MSU crystal deposition was identified in a total of 14 common joints by both observers, and in 4 additional joints by the first observer and 6 additional joints by the second observer. Percentage agreement and kappa statistics for our three primary ultrasound measures were as follows; total joints (n=200, 95% agreement, kappa 0.709), femoral articular cartilage (n=100, 95% agreement, kappa 0.679) and 1st MTPs (n=100, 95% agreement, kappa 0.734). Additional analyses by left and right side are shown in the table below. Ratings on only 10 out of 200 joints were in disagreement. (Table Presented) Conclusions: Both percentage agreement and agreement beyond chance between the raters (as estimated by kappa statistics) were very high for the three ultrasound measures. These findings support the use of MSK-US as a reliable modality for detecting MSU deposition. Since MSU deposition is an indication for urate lowering, this type of imaging could be performed noninvasively at the bedside or in the clinic to help direct therapy in gout patients, with possible implications for treatment in AH patients as well should these findings be reproducible in larger cohorts

OBJECTIVE: The MRI features of the proximal rectus femoris musculotendinous junction have scarcely been described in the literature. The purpose of our study, based on a review of 50 asymptomatic and 20 symptomatic MRI studies, was to define the normal MRI anatomy and MRI features of intrasubstance injury of deep musculotendinous tears of the proximal rectus femoris. CONCLUSION: Axial and coronal MR images are optimal for visualizing the direct and indirect heads, the conjoined tendon, and the deep musculotendinous junction of the proximal rectus femoris. Tears of the deep musculotendinous junction are longitudinal, involving a long segment of the muscle. MRI features include a 'bull's-eye' sign, longitudinal scar, retraction, pseudocyst, and hematoma