Soterios Gyftopoulos

Reproducibility of musculoskeletal ultrasound for determining monosodium urate deposition: concordance between readers.

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.

Diagnostic Accuracy of MRI in the Measurement of Glenoid Bone Loss

OBJECTIVE The purpose of this study is to assess the accuracy of MRI quantification of glenoid bone loss and to compare the diagnostic accuracy of MRI to CT in the measurement of glenoid bone loss. MATERIALS AND METHODS MRI, CT, and 3D CT examinations of 18 cadaveric glenoids were obtained after the creation of defects along the anterior and anteroinferior glenoid. The defects were measured by three readers separately and blindly using the circle method. These measurements were compared with measurements made on digital photographic images of the cadaveric glenoids. Paired sample Student t tests were used to compare the imaging modalities. Concordance correlation coefficients were also calculated to measure interobserver agreement. RESULTS Our data show that MRI could be used to accurately measure glenoid bone loss with a small margin of error (mean, 3.44%; range, 2.06-5.94%) in estimated percentage loss. MRI accuracy was similar to that of both CT and 3D CT for glenoid loss measurements in our study for the readers familiar with the circle method, with 1.3% as the maximum expected difference in accuracy of the percentage bone loss between the different modalities (95% confidence). CONCLUSION Glenoid bone loss can be accurately measured on MRI using the circle method. The MRI quantification of glenoid bone loss compares favorably to measurements obtained using 3D CT and CT. The accuracy of the measurements correlates with the level of training, and a learning curve is expected before mastering this technique.

Normal Variants and Pitfalls in MR Imaging of the Ankle and Foot

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

Imaging in anterior glenohumeral instability.

In the shoulder, the advantages of range of motion are traded for the disadvantages of vulnerability to injury and the development of instability. Glenohumeral instability encompasses a broad spectrum of clinical complaints and presentations. The diagnosis can be obvious or entirely unsuspected. Imaging findings depend on numerous factors and range from gross osseous defects to equivocal labral abnormalities and undetectable capsular lesions. This review focuses on the imaging findings in three distinct clinical scenarios: acute first-time shoulder dislocation, chronic instability with repeated dislocation, and chronic instability without repeated dislocation. The biomechanics of dislocation and the pathophysiology of labral-ligamentous injury are discussed. The authors distinguish the findings that occur in the acutely traumatized shoulder from those that typify the chronic unstable joint. The roles of different imaging modalities are also distinguished, including magnetic resonance arthrography and the value of specialized imaging positions. The goal of imaging depends on the clinical scenario. Image interpretation and reporting may need to emphasize diagnosis and the identification of lesions that are associated with instability or the characterization of lesions for treatment planning.

Increased MR Signal Intensity in the Pronator Quadratus Muscle: Does It Always Indicate Anterior Interosseous Neuropathy?

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.

MRI Evaluation of Bipolar Bone Loss Using the On-Track Off-Track Method: A Feasibility Study.

OBJECTIVE The purpose of this study was to determine whether the simultaneous MRI evaluation of Hill-Sachs lesions and glenoid bone loss by use of the on-track off-track method can be used to predict engagement during arthroscopy. MATERIALS AND METHODS The records of 75 consecutively registered patients (60 male patients, 15 female patients) with a history of previous anterior shoulder instability who underwent preoperative MRI of the shoulder and arthroscopy at our institution were reviewed. A total of 76 MRI examinations were included. Two readers reviewed the MR images of each patient blindly and independently and used the on-track off-track method to predict engagement. These results were compared with the findings related to engagement seen during arthroscopy, which was performed by one of seven orthopedic surgeons. Statistical analyses included Fisher exact test, logistic regression, ROC analysis, and calculation of intraclass correlation coefficients. RESULTS Using the on-track off-track technique of reading MR images, the reviewers correctly predicted 13 of the 18 engaging (off-track) lesions (sensitivity, 72.2%). Among the 58 shoulders that did not engage (on-track), they correctly predicted 51 (specificity, 87.9%). Overall, the accuracy of the on-track off-track method was 84.2% with a positive predictive value of 65.0% and negative predictive value of 91.1%. CONCLUSION Our study showed that the on-track off-track method can be used in MRI to accurately assess the bipolar bone loss seen in patients with anterior shoulder instability for predicting the presence of engaging, or off-track, lesions. This information can be used preoperatively to help guide the type of stabilization procedure performed on patients with anterior shoulder instability.

Engaging Hill-Sachs Lesion: Is There an Association Between This Lesion and Findings on MRI?

OBJECTIVE The objective of our study was to see whether there is an association between engagement on physical examination and the location or size of a Hill-Sachs lesion and the presence and degree of glenoid bone loss as assessed on MRI. MATERIALS AND METHODS Thirty-three consecutive patients (32 males and one female) with a history of anterior shoulder dislocation who underwent preoperative MRI and arthroscopy at our institution and were tested for engagement on physical examination over a 9-month period were included in the study. Two blinded readers reviewed each study independently and documented the presence and size of the Hill-Sachs lesion, location of the Hill-Sachs lesion with a modified biceps angle, and presence and size of glenoid bone loss. Statistical analysis included the Mann-Whitney, logistic regression, Pearson correlation, and intraclass correlation tests. RESULTS Eleven patients had evidence of an engaging Hill-Sachs lesion on physical examination and 22 did not. There was no statistically significant difference between any of the dimensions or overall area of the Hill-Sachs lesion when comparing the group with an engaging Hill-Sachs lesion and the group with a nonengaging lesion (surface area, 3.60 vs 3.23 cm(3), respectively; p = 0.272). There was a trend for a larger biceps angle in the engaging group without a statistically significant difference (mean, 154.5° vs 143.9°; p = 0.069). There was a statistically significant difference in the amount of glenoid bone loss in the engaging group compared with the nonengaging group (mean, 20.2% vs 6.0%; p = 0.001). CONCLUSION There is a significant association between an engaging Hill-Sachs lesion on physical examination and the degree of glenoid bone loss as well as a trend toward increased engagement with more medially oriented Hill-Sachs lesions. These findings show the importance of considering both the Hill-Sachs lesion and glenoid bone loss when evaluating patients with engagement.

Rotator Cable: MRI Study of Its Appearance in the Intact Rotator Cuff With Anatomic and Histologic Correlation

OBJECTIVE The purpose of this study was to define and correlate the appearance of the rotator cable on MRI with arthroscopy, band-saw cadaveric sections, and histology. MATERIALS AND METHODS Two cadaveric shoulders underwent 3-T MRI, band-sawing, and histologic evaluation. Three readers evaluated the MRI for the presence of the cable, and the same readers and a pathologist reviewed the macroscopic and microscopic specimens for a structure that corresponded to the cable. Cadaver 1 underwent arthroscopic evaluation to evaluate for the presence of a cable. Seventy consecutive shoulders that underwent 1.5- or 3-T MRI were also reviewed for the presence of the cable and evaluation of its characteristics (location, thickness, and width). RESULTS A linear band of hypointense signal intensity was found along the undersurface of the supraspinatus and infraspinatus tendons on both cadaveric MR images, which correlated to a linear band of tissue in the same location on macroscopic and microscopic evaluation and linear thickening along the cuff articular surface on arthroscopy consistent with the cable. The cable was seen in 74.3% of the MRI studies in both sagittal and coronal planes with a mean (± SD) distance of the cable from the medial margin of the enthesis of 1.33 ± 0.27 cm, a mean width of the cable of 1.24 ± 0.31 cm, and a mean thickness of 0.19 ± 0.05 cm. CONCLUSION The rotator cable is a structure that can be consistently seen on gross anatomic and histologic analysis, arthroscopy, and MRI in the intact rotator cuff. Familiarity with the typical location and morphology of the cable may allow easier characterization of disease that can involve the cable, such as rotator cuff tears.

Presence of gout is associated with increased prevalence and severity of knee osteoarthritis among older men: results of a pilot study.

BackgroundGout and osteoarthritis (OA) are the most prevalent arthritides, but their relationship is neither well established nor well understood. ObjectivesWe assessed whether a diagnosis of gout or asymptomatic hyperuricemia (AH) is associated with increased prevalence/severity of knee OA. MethodsOne hundred nineteen male patients aged 55 to 85 years were sequentially enrolled from the primary care clinics of an urban Veterans Affairs hospital, assessed and categorized into 3 groups: gout (American College of Rheumatology Classification Criteria), AH (serum urate ≥6.8 mg/dL, no gout), and control (serum urate <6.8 mg/dL, no gout). Twenty-five patients from each group subsequently underwent formal assessment of knee OA presence and severity (American College of Rheumatology Clinical/Radiographic Criteria, Kellgren-Lawrence grade). Musculoskeletal ultrasound was used to detect monosodium urate deposition at the knees and first metatarsophalangeal joints. ResultsThe study showed 68.0% of gout, 52.0% of AH, and 28.0% of age-matched control subjects had knee OA (gout vs control, P = 0.017). Odds ratio for knee OA in gout versus control subjects was 5.46 prior to and 3.80 after adjusting for body mass index. Gout subjects also had higher Kellgren-Lawrence grades than did the control subjects (P = 0.001). Subjects with sonographically detected monosodium urate crystal deposition on cartilage were more likely to have OA than those without (60.0 vs 27.5%, P = 0.037), with crystal deposition at the first metatarsophalangeal joints correlating most closely with OA knee involvement. ConclusionsKnee OA was more prevalent in gout patients versus control subjects and intermediate in AH. Knee OA was more severe in gout patients versus control subjects.

Arthroscopic Anatomic Humeral Head Reconstruction With Osteochondral Allograft Transplantation for Large Hill-Sachs Lesions

Anatomic reconstruction of the humeral head with osteochondral allograft has been reported as a solution for large Hill-Sachs lesions with or without glenoid bone loss. However, to date, varying techniques have been used. This technical note describes an arthroscopic reconstruction technique using fresh-frozen, side- and size-matched osteochondral humeral head allograft. Allograft plugs are press fit into the defect without internal fixation and seated flush with the surrounding articular surface. This technique restores the native articular contour of the humeral head without compromising shoulder range of motion. Potential benefits of this all-arthroscopic approach include minimal trauma to the soft tissue and articular surface without the need for hardware or staged reoperation.