Supraspinatus muscle location changes after arthroscopic rotator cuff repair: a potential source of preoperatively predicting tear patterns

Yohei Ono,1 Takeshi Makihara,2 Satoshi Yamashita,3 Kelvin KW Tam,4 Nobuaki Kawai,1 Ian KY Lo,5 Akihiko Kimura1 1Department of Orthopaedic Surgery, East Hokkaido Hospital, Kushiro, Hokkaido, Japan; 2Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan; 3Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan; 4Asia Medical Specialists, Hong Kong, China; 5Department of Surgery, Section of Orthopaedic Surgery, McCaig Institute for Bone and Joint Health, University of Calgary, NW, Calgary, AB, Canada Purpose: When repairing retracted rotator cuff tears, the tear pattern (eg, crescent-shaped, L-shaped) is best determined intraoperatively by evaluating the mobility of the tendon in multiple directions. The purpose of our study was to evaluate the location of the supraspinatus (SSP) muscle belly on magnetic resonance imaging (MRI) in patients undergoing arthroscopic repair of retracted rotator cuff tears. We hypothesized that the location of the rotator cuff muscle would move after tendon repair, and that the perioperative change in muscle position would correlate with the tear pattern.Methods: A series of primary arthroscopic repairs for rotator cuff tears with >3 cm of medial retraction from 2015 to 2016 was reviewed. MRIs were performed preoperatively and within 10 days postoperatively. The SSP muscle was assessed on sagittal MRI and evaluated for the “occupation ratio”, “tangent sign”, and the “location index” proposed in this study. Pre and postoperative MRIs were compared, and correlated with intraoperatively determined tear patterns. Fifty shoulders without rotator cuff pathology were also assessed for the “location index” as control.Results: Fifty-nine shoulders (mean age 65.0 years) were included, among which five reverse L-shaped tears were identified. The occupation ratio and tangent sign improved postoperatively. Preoperatively, in the majority of tears, the SSP muscle was located more posteriorly in the SSP fossa, compared to the control group, and shifted anteriorly after repair. However, in reverse L-shaped tears the SSP muscle was located more centrally in the fossa, and shifted posteriorly following repair.Conclusion: Rotator cuff tearing and arthroscopic rotator cuff repair change the location of the SSP muscle. Although repair usually results in shifting of the muscle belly from posterior to anterior, reverse L-shaped tears demonstrated an opposite pattern. The location of the SSP muscle belly may be useful in predicting tear patterns of retracted rotator cuff tears.Level of evidence: Level IV (case series). Keywords: shoulder, rotator cuff, muscle belly, muscle location, MRI, muscle atrophy, tendon retraction, location inde

Transtendon rotator-cuff repair of partial-thickness articular surface tears can lead to medial rotator-cuff failure

Tom C Woods,4 Michael J Carroll,1 Atiba A Nelson,2 Kristie D More,2 Randa Berdusco,1 Stephen Sohmer,3 Richard S Boorman,1,2 Ian KY Lo1,21Department of Surgery, 2Sport Medicine Centre, University of Calgary, Calgary, AB, Canada; 3Department of Orthopaedics, University of British Columbia, Vancouver, 4St Joseph's Hospital, Comox, BC, CanadaPurpose: The purpose of this study was to evaluate clinical and anatomic outcomes of patients following transtendon rotator-cuff repair of partial articular supraspinatus tendon avulsion (PASTA) lesions.Patients and methods: Patients in the senior author's practice who had isolated PASTA lesions treated by transtendon rotator-cuff repair were included (n=8) and retrospectively reviewed. All patients were evaluated preoperatively and at a mean of 21.2 months (±9.7 months) postoperatively using standardized clinical evaluation (physical exam, American Shoulder and Elbow Surgeons, and Simple Shoulder Test). All patients underwent postoperative imaging with a magnetic resonance imaging arthrogram.Results: There was a significant improvement in American Shoulder and Elbow Surgeons (42.7±17.5 to 86.9±25.2) and Simple Shoulder Test (4.6±3.2 to 10.1±3.8) scores from pre- to postoperative, respectively. Postoperative imaging demonstrated full-thickness medial cuff tearing in seven patients, and one patient with a persistent partial articular surface defect.Conclusion: Transtendon repair of PASTA lesions may lead to improvements in clinical outcome. However, postoperative imaging demonstrated a high incidence of full-thickness rotator-cuff defects following repair.Keywords: rotator cuff, PASTA lesion, transtendon repai

Redefining anterior shoulder impingement: a literature review

Many different types of impingements have been described in the shoulder. Inasmuch as the term 'shoulder impingement' usually refers to subacromial impingement, anterior impingement usually refers to subcoracoid impingement. However, there are many different subtypes of anterior impingements in the shoulder, and awareness of their existence is critical as they vary in their nature and treatment. Recent advances in biomechanical research and arthroscopic exploration of the anterior structures of the shoulder have brought new insights on the various potential impingements, warranting a revision and update of the current definitions of anterior shoulder impingement. The purpose of this article is to propose a comprehensive review and classification of all different subtypes of anterior impingement in the shoulder, including newly described entities

Comparison between single-row and double-row rotator cuff repair: a biomechanical study

The aim of this study was to compare the mechanical behavior under cyclic loading test of single-row and double-row rotator cuff repair with suture anchors in an ex-vivo animal model. For the present study, 50 fresh porcine shoulders were used. On each shoulder, a crescent-shaped full-thickness tear of the infraspinatus was performed. Width of the tendon tear was 2 cm. The lesion was repaired using metal suture anchors. Shoulders were divided in four groups, according the type of repair: single-row tension-free repair (Group 1); single-row tension repair (Group 2); double-row tension-free repair (Group 3); double-row tension repair (Group 4); and a control group. Specimens were subjected to a cyclic loading test. Number of cycles at 5 mm of elongation and at failure, and total elongation were calculated. Single-row tension repair showed significantly poorest results for all the variables considered, when compared with the other groups. Regarding the mean number of cycles at 5 mm of elongation and at failure, there was a nonsignificant difference between Groups 3 and 4, and both of them were significantly greater than Group 1. For mean total elongation, the difference between Groups 1, 3, and 4 was not significant, but all of them were significantly lower than the control group. A single-row repair is particularly weak when performed under tension. Double-row repair is significantly more resistant to cyclic displacement than single-row repair in both tension-free and tension repair. Double-row repair technique can be primarily considered for large, unstable rotator cuff tears to improve mechanical strength of primary fixation of tendons to bone

The functional outcome of total tears of the anterior cruciate ligament (ACL) in the skeletally immature patient

Tears of the anterior cruciate ligament (ACL) in the skeletally immature patient are becoming more prevalent. The aim of this study was to describe the functional outcome and to evaluate the best management of total tears of the ACL in skeletally immature patient. Twenty consecutive, skeletally immature patients with a clinically evident rupture of the anterior cruciate ligament were followed up for a mean of 5.4 years. The mean age at the time of injury was 13.9 years old. The study group consisted of 13 girls and 7 boys, who were treated either conservatively, by ACL reconstruction, by primary repair or by delayed ACL reconstruction after skeletal maturity had been reached. Clinical outcomes were measured using the International Knee Documentation Committee Scoring System (IKDC) and the Knee Injury and Osteoarthritis Outcome Scoring System (KOOS). The radiological evaluation was performed using Jaeger and Wirth's criteria, and instrumented laxity testing was carried out with a Rolimeter. Five of the eight patients treated conservatively showed poor function of the knee, and this resulted in instability. Concerning the patients treated by primary repair, delayed ACL reconstruction or arthroscopic debridement, we also found none of the results to be satisfactory (seven of eight patients). The patients that were treated by a reconstruction had the best results. This was confirmed by clinical examination (Lachmann grade 1), by the IKDC (grade B) and by the KOOS with the best quality of life and no giving-way attacks. The level of evidence was therapeutic level III