A novel diagnostic method to predict subscapularis tendon tear with sagittal oblique view magnetic resonance imaging.

PURPOSE: To find novel measurement guidelines correlating with known tear size on two sagittal oblique views (en-face view and Y-view). METHODS: From a series of arthroscopic rotator cuff repair cases between 2012 and 2015, 50 patients were randomly selected from each of six subscapularis tear classifications. Due to rarity of type IV lesions, 272 shoulders were included. En-face view and Y-view in sagittal plane MRI were selected. Image evaluation was retrospectively performed by two researchers independently. In en-face view, anatomical line connecting the coracoid tip to the glenoid base designated as the base-to-tip line was used for thickness measurement and classification. Grading according to base-to-tip line, overlapped segment of base-to-tip line, thickness of subscapularis, and fluid accumulation were measured. In Y-view, a tangent line was drawn through the scapular spine and the coracoid. Parallel lines were then made. Grading according to tangent line, vertical length, cephalic width, caudal width, and fluid accumulation was measured. RESULTS: In en-face view, grading according to base-to-tip line and overlapped segment of base-to-tip line showed differences in subscapularis tendon tear types IIB, III, and IV compared to the normal group. Thickness of subscapularis showed differences in types III and IV. No significant difference was observed in fluid accumulation. In Y-view, grading according to tangent line, vertical length, cephalic width, and fluid accumulation showed significant differences in types III and IV. Caudal width in Y-view was significantly different only in type IV. CONCLUSION: Several measurement parameters in two additional views in sagittal-oblique MRI (en-face view and Y-view) showed different degrees of subscapularis tendon tears. Grading of base-to-tip line is easy to use and helps diagnose partial subscapularis tear. LEVEL OF EVIDENCE: III.

Length change behavior of virtual medial patellofemoral ligament fibers during in vivo knee flexion.

BACKGROUND: In vivo length change behavior of native medial patellofemoral ligament (MPFL) fibers throughout the range of knee motion has not been reported in vivo. PURPOSE: To measure the length changes of various fibers of the MPFL and to determine their length change patterns during in vivo passive knee flexion. STUDY DESIGN: Descriptive laboratory study. METHODS: The right knees of 11 living subjects were scanned with a high-resolution computed tomography scanner at 0°, 30°, 60°, 90°, and 120° of knee flexion, and 3-dimensional (3D) models were constructed using customized software. Five patellar points were determined: 20% (point 20), 30% (point 30), 40% (point 40), 50% (point 50), and 60% (point 60) from the superior pole of the patella. The Schöttle femoral point (point F) was marked on a translucent 3D model of a true lateral view. Five virtual fibers connecting these points on the 3D knee model were created, and the lengths of various fibers were digitally measured. RESULTS: The average length changes were 9.1±2.5 mm in F20, 9.1±2.5 mm in F30, 8.1±2.6 mm in F40, 6.9±2.4 mm in F50, and 6.9±1.7 mm in F60. There were significant differences in length changes of these 5 fibers (P<.001). The lengths of 2 superior fibers (F20 and F30) increased as the knee flexed from 0° to 30° and decreased as the knee flexed over 30°. The lengths of a middle fiber (F40) and an inferior fiber (F50) increased from 0° to 30°, reached a plateau from 30° to 60°, and then decreased from 60° to 120°. F60 showed an increase from 0° to 30°, and then a plateau pattern from 30° to 90°, followed by a decrease during further flexion. CONCLUSION: Superior fibers exhibited their maximum lengths at low flexion angles, and inferior fibers exhibited their maximum lengths at midflexion angles. The MPFL is a complex of functionally various fibers with some taut and others slack over the whole range of knee motion. CLINICAL RELEVANCE: The results for lengths and length change patterns of various MPFL fibers are expected to serve as a theoretical background for anatomic double-bundle MPFL reconstruction.

Delayed infrarenal aortic pseudoaneurysm treated by endovascular stent graft in pyogenic spondylitis.

A 61-year-old male patient with pyogenic spondylodiscitis and epidural and psoas abscesses underwent posterior decompression, debridement, and instrumented fusion, followed by anterior debridement and reconstruction. Sudden onset flank pain was diagnosed 7 weeks postoperatively and was determined to be a pseudoaneurysm located at the aorta inferior to the renal artery and superior to the aortic bifurcation area. An endovascular stent graft was applied to successfully treat the pseudoaneurysm. Postoperative recovery was uneventful and infection status was stabilized.