4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:972-991.

• Identification of the surgical approach is well possible with MR imaging. • Anterolateral/anterior approaches show less soft-tissue damage compared to lateral/posterior approaches. • Posterior approaches show marked damage to external rotator tendons and muscles. • After direct lateral approaches the gluteus minimus tendon/muscle show severe damage.

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam-and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam-and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. After reading the article and taking the test, the reader will be able to:n Describe biomechanical implications of torsional malalignment and other atypical forms of hip impingement n Describe the most common MR imaging findings in femoroacetabular impingement and identify anatomic variants n Describe imaging characteristics of a Morel-Lavallée lesion and identify the anatomic compartment where this lesion typically occurs n Identify common stress fractures around the hip joint in athletes and discuss potential complications n Describe features of myotendinous injuries around the hip n Describe the anatomic relationship of the sacrotuberous ligament and the origin of the hamstring tendons n Describe the anatomic structures involved in an athletic pubalgia Accreditation and Designation Statement The RSNA is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. The RSNA designates this journal-based SA-CME activity for a maximum of 1.0 AMA PRA Category 1 Credit ™ . Physicians should claim only the credit commensurate with the extent of their participation in the activity. Disclosure StatementThe ACCME requires that the RSNA, as an accredited prov...

Background: Failed back surgery syndrome (FBSS) is a therapy-refractory pain condition characterized by persistent low back pain after spine surgery. FBSS is associated with severe disability, low quality of life and high unemployment rate. We are currently unable to identify patients who are at risk of developing FBSS. Patients with chronic low back pain may display signs of central hypersensitivity as assessed by quantitative sensory tests (QST). This can contribute to patients' vulnerability to develop persistent pain after surgery. Objective: We tested the hypothesis that central hypersensitivity as assessed by QST predicts FBSS. Design and Setting: We performed a prospective cohort study in 141 patients with chronic low back pain scheduled for up to three segmental spine surgery for chronic low back pain due to degenerative changes in three tertiary care centres. Patients: Chronic low back pain was defined as of at least 3 on a numerical rating scale at most days during the week and with a minimum duration of three months. Outcomes: We defined FBSS as persistence of pain, persistence of disability or a composite outcome defined as either persistence of pain or disability. The primary outcome was persistence of pain 12 months after surgery. We applied 14 QST using electrical, pressure and temperature stimulation to predict FBSS and assessed the association of QST with FBSS in multivariable analyses adjusted for socio-demographic, psychological and clinical and surgery-related characteristics. Results: None of the investigated 14 QST predicted FBSS, with 95% confidence intervals of crude and adjusted associations of all QST including one as measure of no association. Results remained robust in all sensitivity and secondary analyses. Conclusion: The study indicates that assessment of altered central pain processing using current QST is unlikely to identify patients at risk for FBBS and is therefore unlikely to inform clinical decisions.

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BACKGROUND One recognized salvage option in the treatment of an irreparable subscapularis tear is the pectoralis major tendon transfer (PMT). We aimed to analyze the long-term clinical and imaging outcome of PMT for irreparable subscapularis deficiency. METHODS Twenty-eight consecutive patients representing 30 shoulders underwent PMT at a mean age of 53.0 years (range, 35 to 67 years). At a mean of 19.7 years (range, 18 to 22 years) postoperatively, 24 shoulders (80%) were clinically examined and 21 were radiographically and sonographically assessed. The long-term results were compared with preoperative findings and previously published short-term results. RESULTS The mean relative Constant score (percentage of age and sex-matched normal scores; CS%) and the Subjective Shoulder Value (SSV) both improved significantly from preoperatively (CS%, 47%, and SSV, 22%) to postoperatively (CS%, 77%, and SSV, 71%; p < 0.001 for both). All patients rated their results as good or excellent. Active anterior elevation was improved from preoperatively (120°) to postoperatively (131°), but the difference was not significant. Active internal and external rotation decreased significantly from the short-term (32month) follow-up to the time of the latest follow-up (p = 0.005 and p = 0.002, respectively); however, internal rotation remained at 6 points compared with the 8 points recorded at short-term follow-up and external rotation decreased only from a mean of 51°to 39°. Loss of active range of motion was not observed subjectively and was not subjectively limiting, represented by the high ultimate SSV and overall satisfaction. Four shoulders (19%) showed evidence of glenohumeral arthropathy (Samilson and Prieto grade 3), but clinically were mildly symptomatic to asymptomatic at the time of the latest follow-up (CS% range, 67% to 88%; SSV range, 70% to 80%). Rupture of the PMT was sonographically identified in 2 patients (10%) and was associated with radiographic evidence of advanced cuff tear arthropathy (Hamada stages 4). Six (20%) of the initial 30 shoulders were revised, and 1 (4%) of the 24 shoulders that were clinically examined underwent reverse total shoulder arthroplasty. CONCLUSIONS At longterm follow-up, PMT for isolated and combined subscapularis tears is associated with good to excellent clinical results. Although one-third of the shoulders developed mildly symptomatic or asymptomatic osteoarthritis, the need for salvage with use of reverse total shoulder arthroplasty was rare. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

• Multi-echo Dixon for low fat quantification in muscles is reliable. • Multi-echo Dixon low fat quantification is comparable to single-voxel MR spectroscopy • Multi-echo Dixon detects substantial differences in fatty infiltration within Goutallier 0-1.

FA inversely correlates with pain and may be a useful imaging parameter for assessment of DOMS. Shear-wave US elastography shows a temporary increase of muscle stiffness after DOMS-inducing exercise but does not correlate with quantitative MRI parameters or clinical symptoms.