Shoulder Positioning during Superior Capsular Reconstruction: Computational Analysis of Graft Integrity and Shoulder Stability

The shoulder position during fixation of the graft may be a key factor impacting the outcome of arthroscopic superior capsular reconstruction (ASCR) in irreparable rotator cuff tears (IRCTs). However, biomechanical evidence regarding this effect is lacking. The aim of this study was to evaluate the influence of the shoulder position during fixation of the graft on shoulder stability and graft tear risk in ASCR. A 3-D musculoskeletal model of the upper limb was modified to account for the fixation of the graft in ASCR, assuming a full-thickness tear of the supraspinatus tendon. The concomitant tenotomy of the long head of the biceps (LHB) tendon was also studied. The biomechanical parameters evaluated included the strain of the graft and the glenohumeral joint reaction force (GH JRF), which were used to evaluate graft integrity and shoulder stability, respectively. Fixation of the graft considering abduction angles greater than 15° resulted in a high risk for graft tearing when the arm was adducted to the side of the trunk. For abduction angles below 15°, the mean shoulder stability improved significantly, ranging between 6% and 20% (p < 0.001), compared with that in the preoperative condition. The concomitant tenotomy of the LHB tendon resulted in loss of stability when compared to ASCR with an intact LHB tendon. The position of the shoulder during fixation of the graft has a significant effect on shoulder stability and graft tear risk after ASCR in IRCTs. This study provides new and important information regarding the role of shoulder positioning during fixation of the graft.

Three-dimensional SPACE MR with CAIPIRINHA fourfold acceleration for assessing long head of biceps tendon

Background Data regarding controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) T2-weighted sampling perfection with application optimized contrast evolution (SPACE) with fourfold acceleration factor for assessing long head of biceps tendon (LHBT) disorder is lacking. Purpose To investigate the feasibility of 3D CAIPIRINHA SPACE with fourfold acceleration in assessing LHBT disorder. Material and Methods A total of 42 consecutive patients underwent shoulder magnetic resonance (MR) examinations including CAIPIRINHA SPACE with fourfold acceleration, and non-CAIPIRINHA SPACE with twofold acceleration, and 2D fast spin echo (FSE). A subjective score of depiction of LHBT was given to 3D sequence according to a 4-point scale (0–3, “poor” to “excellent”). The Wilcoxon signed rank test was used to compare depiction scores between 3D sequences. Three statuses of LHBT were defined in the study: normal, tendonitis, and tear. McNemar’s test was used compare diagnostic accuracy. Results LHBT was better depicted with CAIPIRINHA SPACE versus non-CAIPIRINHA SPACE (2.1 ± 0.4 vs. 1.5 ± 0.4; P < 0.001). Inter-modality agreement between CAIPIRINHA SPACE and 2D FSE was almost perfect (kappa = 0.884 ± 0.064). The sensitivity and specificity in detecting LHBT disorder were 95% (20/21) and 95% (20/21), respectively, for CAIPIRINHA SPACE, and 71% (15/21) and 76% (16/21), respectively, for non-CAIPIRINHA SPACE ( P = 0.039). Conclusion Fourfold acceleration CAIPIRINHA is feasible in reducing the acquisition time of SPACE MR in the shoulder. 3D CAIPIRINHA SPACE with fourfold acceleration is highly accurate in detecting LHBT disorder.

Ultrasound-Guided Musculoskeletal Injections

Musculoskeletal injections serve a variety of diagnostic and therapeutic purposes, with ultrasonography (US) guidance having many advantages: no ionizing radiation, real-time guidance, high spatial resolution, excellent soft tissue contrast, and the ability to identify and avoid critical structures. Sonography can be cost effective and afford flexibility in resource-constrained settings. This article describes US-guided musculoskeletal injections relevant to many radiology practices and provides experience-based suggestions. Structures covered include multiple joints (shoulder, hip), bursae (iliopsoas, subacromial-subdeltoid, greater trochanteric), peripheral nerves (sciatic, radial), and tendon sheaths (posterior tibial, peroneal, flexor hallucis longus, Achilles, long head of the biceps). Trigger point and similar targeted steroid injections, as well as calcific tendinopathy barbotage, are also described.

Distance between the supraspinatus and long head of the biceps tendon on sagittal MRI: a new tool to identify anterior supraspinatus insertion injury

Purpose Anterior insertion of the supraspinatus muscle plays an essential role in rotator cuff tissue. We aimed to determine whether the distance between the midpoints of the supraspinatus central tendon and long head of the biceps tendon on a sagittal shoulder magnetic resonance imaging scan can help to preoperatively diagnose an injury of the anterior insertion of the supraspinatus. Method This retrospective study reviewed 103 patients with a full-thickness supraspinatus tendon tear: 50 patients with (injured group) and 53 patients without (intact group) anterior supraspinatus insertion tear. The inter-tendon distance was measured based on an oblique sagittal magnetic resonance imaging scan. SPSS was used for statistical analyses. Two independent samples t-test and receiver operating curve analysis were also performed. Results The measurements of inter-tendon distance revealed good intra- and inter-observer reliabilities with intra-class correlation coefficients of 0.92 and 0.97, respectively. The inter-tendon distance of the injured group was significantly greater than that of the intact group (10.1 ± 2.7 vs 8.0 ± 2.3 mm, P < 0.001). The diagnostic ability of the inter-tendon distance was fair (area under the curve = 0.745), and a threshold of 9 mm had a specificity of 73% and sensitivity of 74%. Conclusion The distance between the supraspinatus central tendon and long head of the biceps tendon on magnetic resonance imaging was greater in patients with anterior supraspinatus insertion injury than those without the injury. A distance of 9 mm may be the cut-off value and a good diagnosis marker for anterior supraspinatus insertion injury. Level of evidence Level III, diagnostic case–control study.