Unicortical Button Fixation Provide Higher Strength Compared with Transosseous Repair for Subscapularis Tendon in Total Shoulder Arthroplasty.

BACKGROUND: Subscapularis tendon (SSc) dysfunction following total shoulder arthroplasty (TSA) results in poor functional outcomes. There have been numerous SSc repair constructs tested biomechanically and clinically, however, none has been demonstrated as superior. Newer techniques and implants have emerged, but have not been fully tested. HYPOTHESIS: We hypothesized that the unicortical button (UB) fixation will provide significantly improved restoration of the anatomic footprint and biomechanical properties when compared to transosseous (TO) repair of the SSc. METHODS: A digital footprint of SSc humeral insertion was obtained in 6 pairs of fresh-frozen cadaveric shoulders using a three-dimensional (3-D) digitizer. A complete SSc tear was created, and each pair of shoulders was randomized to either SSc repair with UB or TO repair. Each specimen underwent a cyclic loading protocol followed by pull-to-failure. The failure load, elongation at failure, gapping failure, number of cycles until failure, the load at key gapping points (1 mm, 3 mm, 5 mm, and 10 mm) and the failure mode were recorded using high-resolution video recording. 3-D surfaces of the insertion footprint and repair site were obtained, and surface areas were calculated using a custom MATLAB script and laser scanner. Paired t-tests were conducted to compare differences between two repair groups. RESULTS: Failure load was significantly higher in the UB group (382.4 N ± 56.5 N) than in the TO group (253.6 N ± 103.4 N, p=0.005). TO repair provided higher gapping at failure (28.8 mm ± 8.2 mm) than UB repair (10.4 mm ± 6.8 mm, p=0.0017). UB repair had significantly higher load at the 1-mm, 5-mm, and 10-mm gapping compared with TO repair with p=0.042, p=0.033, and p=0.0076, respectively. There were no significant differences between elongation failure, the difference in footprint area from native to repair states, or the percentage of restored footprint area between groups. (p=0.26, p=0.18 and p=0.21 respectively) CONCLUSION: The UB fixation showed a significantly lower gap at failure, higher failure load and number of cycles until failure, and higher gap loads compared with the traditional TO repair for SSc. Although more clinical research is necessary, the UB fixation that utilizes cortical bone presents promising results.

Retrospective analysis of the subscapularis-sparing approach for reverse total shoulder arthroplasty.

PURPOSE: The influence of the subscapularis tendon on reverse total shoulder arthroplasty (RTSA) has been discussed controversially. The aim of the study was to investigate the subscapularis-sparing approach for RTSA and the effect of the intact subscapularis tendon. METHODS: This retrospective comparative study included 93 patients. Among these, 55 underwent the deltopectoral subscapularis-sparing approach, and in 38 cases, the standard deltopectoral approach with subscapularis tenotomy was applied. At the final follow-up, representative shoulder scores were measured, radiographs were taken in two planes, and shoulder sonography was performed. RESULTS: The subscapularis-sparing group showed a significantly higher Constant score (71.8 vs. 65.9 points) and adapted Constant score if the subscapularis tendon was shown to be intact in the postoperative sonography (85.2% vs. 78.6%) (p = 0.005; p = 0.041). Furthermore, these patients had improved abduction (128.2 vs. 116.8, p = 0.009) and external rotation (34.6 vs. 27.1, p = 0.047). However, no significant differences were found for the degree of internal rotation and internal rotation strength. No dislocation or infection was observed. The degree of scapular notching was not significantly different between the two groups (p = 0.082). However, independently from the integrity of the subscapularis the subscapularis-sparing approach showed no difference in clinical and radiographic outcome (Constant score scapularis-sparing 70.0 points vs. tenotomy 66.8 points; p = 0.27). CONCLUSION: The subscapularis-sparing approach RTSA showed improved clinical outcome, abduction, and external rotation, if the subscapularis was shown to be intact at time of follow-up. Both groups showed no difference in internal rotation.

Arthroscopic repair for isolated subscapularis tear: successful functional outcomes and high tendon healing rate can be expected nine years after surgery.

BACKGROUND: Literature describing outcomes and integrity after isolated subscapularis (SSC) tendon repair is emerging but remains limited to a few small case series with short-term follow-up. The aim of this study was to evaluate the long-term clinical outcomes and repair integrity in patients who underwent arthroscopic repair of isolated SSC tears. METHODS: A retrospective study was conducted with the following inclusion criteria: (1) primary and elective shoulder arthroscopy for isolated SSC repair, (2) type III (a full-thickness tear in the upper two-thirds of the tendon) or IV (a complete tear without tendon retraction) SSC tear according to the Lafosse classification, and (3) a minimum 24-month follow-up. Preoperatively, the range of motion (ROM) and the Constant-Murley score (CMS) and at follow-up, the ROM, the University of California-Los Angeles (UCLA) Shoulder Rating Scale, the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, and the CMS were evaluated; an ultrasonographic assessment of tendon healing was performed according to the Sugaya classification. RESULTS: The final sample consisted of 45 patients with an average age of 55 ± 9 years. After a mean follow-up time of 107 ± 54 months, the mean UCLA and DASH scores were 8.7 ± 1.3 and 42.2 ± 6.4, respectively. ROM and CMS showed statistically significant improvements (all P < .001). Before surgery, the mean CMS was 49% that of sex- and age-matched healthy individuals, and all patients showed a CMS lower than the normative data. At the final follow-up visit, the mean CMS was 94.2% that of sex- and age-matched healthy individuals, and no patients showed CMS of 30 or less. The mean increase in the CMS was 41.4 ± 9.8 points (range, 23-60 points). The ultrasonographic assessment showed SSC tendon healing in 39 (86.7%) cases; tendon retear was recorded in 5 (13.3%) cases. All scores directly correlated with the healing of the tendon. A higher postoperative DASH score was associated with male sex (P = .039, ß = 5.538) and a longer follow-up period (P = .044, ß = 0.001). The postoperative CMS (P < .001) and UCLA scores (P = .001) were significantly higher in patients younger than 60 years of age at surgery than in older individuals. CONCLUSION: Arthroscopic repair of isolated SSC tears achieves excellent clinical and functional results at a mean of 9 years postoperatively, with a satisfactory healing rate. Better functional outcomes correlate with SSC tendon integrity and were observed in male patients and in those younger than 60 years at surgery.

Clinical outcomes and temporal changes in the range of motion following reverse total shoulder arthroplasty.

BACKGROUND: Reverse total shoulder arthroplasty is a definitive solution for the treatment of massive rotator cuff tear and shoulder pseudoparalysis since it can improve shoulder function, especially in elderly individuals. For many elderly individuals, the concern is when they can return to their daily lives after surgery. This study aimed to clarify the characteristics of temporal postoperative values following reverse total shoulder arthroplasty and investigate the factors that affect clinical outcomes. METHODS: This study included 52 patients (mean 79.2 years, range 70-87 years) who underwent primary reverse total shoulder arthroplasty for shoulder pseudoparalysis at a single institution by a single surgeon using the same implant between October 2014 and June 2019. We divided 52 patient into the following groups (1) female (n = 34)vs. male (n = 18) patients; (2) with (n = 19) vs. without (n = 33) arthritic changes in glenohumeral joints (Hamada grade 2, 3 vs. 4, 5); (3) with (n = 23) vs. without (n = 29) subscapularis tendon repair; and investigated the temporal changes in the range of motion (flexion, abduction, external rotation, and internal rotation) and American Shoulder and Elbow Surgeons scores. RESULTS: Significant differences were observed in postoperative shoulder flexion (P = .046) and abduction (P = .049) between the female and male groups. The male patients were able to obtain quick functional recovery. However, no significant differences were observed in postoperative American Shoulder and Elbow Surgeons scores, and the shoulder range of motion between patients with Hamada grade 2, 3 and 4, 5, and between the subscapularis repair and no repair groups. CONCLUSION: The factor that affected the final and temporal values of range of motion after reverse total shoulder arthroplasty was sex, rather than the arthritic changes in glenohumeral joint and the treatment of the subscapularis tendon.

High diagnostic accuracy of magnetic resonance imaging in detecting subscapularis tendon tears by focusing on the most superior portion of the subscapularis tendon.

PURPOSE: This study aimed to test the hypothesis that identifying the exact location of the most superior portion of the subscapularis tendon using magnetic resonance imaging (MRI) provides high diagnostic accuracy in detecting subscapularis tendon tears. METHODS: This study included 157 patients who underwent primary arthroscopic rotator cuff repair between 2014 and 2017. All patients underwent conventional 1.5-T MRI in our hospital, within 3 months before surgery. We retrospectively compared the diagnosis of subscapularis tendon tears using MRI based on an anatomical concept focusing on the superior-most insertion point of the subscapularis tendon with intraoperative arthroscopic findings. RESULTS: Subscapularis tendon tears were detected in 80 (51.0%) of the 157 patients during arthroscopic evaluation. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the MRI examination were 90, 83, 85, 89, and 87%, respectively. With a kappa score of 0.83, the concordance rate between the two raters was almost perfect (95% confidence interval, 0.75-0.92). The sensitivities of the oblique-sagittal and axial sequences were 84 and 79%, respectively. CONCLUSIONS: Preoperative MRI evaluation focusing on the most superior portion of the subscapularis tendon demonstrated high diagnostic accuracy in detecting subscapularis tendon tears. To find the most superior portion of the subscapularis tendon tears, it was essential to check the slice at the level of the lesser tubercle tip and its adjacent slice. In addition, the combined observation of oblique-sagittal and axial sequences helped to detect subscapularis tendon tears with higher sensitivity.

Is it the subcoracoid impingement or the subacromial impingement that tears the subscapularis tendon? A comparison of the MRI findings of the operated and healthy shoulders of the patients.

BACKGROUND: : The purpose of this study is to investigate whether the etiological factors accepted as causes of idiopathic subscapularis tears are true or not when the comparison is made with the opposite side healthy shoulder of the patients who underwent arthroscopic repair for an isolated subscapularis tear. METHODS: Sixteen patients who underwent shoulder arthroscopy between February 2016 and January 2018 and were diagnosed with isolated subscapularis tear were evaluated. The coracohumeral distance (CHDax), coracoid overlap (CO), and tuberculum minus cysts (TMC) were evaluated on the axial images of the MRI studies while the acromiohumeral distance (AHDsag), CHDsag, and subscapularis tendon slip number (STSN) on the sagittal oblique images and the AHDcor and SLAP lesion on the coronal oblique images. Degeneration of the coracoacromial ligament was evaluated during arthroscopy. RESULTS: The mean CHDsag (11.26-10.08), CHDax (10.63-9.98), CO (14.2-15.43), AHDsag (8-7.66), and AHDcor (7.65-7.68) measurements (operated side-healthy side, respectively) were statistically similar (p > 0.05). No statistically significant difference was found between TMC and STSN in healthy and operated shoulders (p > 0.05). There was mild coracoacromial ligament fraying in 4 (25%) and obvious coracoacromial ligament fraying in 8 (50%) which indicated subacromial impingement in 75% of the patients. DISCUSSION: The parameters of the coracoid process did not reveal any significant difference between the operated (for an isolated subscapularis tear) and opposite-side healthy shoulders of the patients. However, coracoacromial ligament degeneration was present in 75% of the patients.

Correlation between preoperative clinical examination and intraoperatively found subscapularis tendon tear.

PURPOSE: Analyze the diagnostic value for subscapularis (SSC) tendon tears, their correlation between pain and strength on clinical tests, and compare them with intraoperative arthroscopic findings to prove their diagnostic value. METHODS: 110 consecutive patients undergoing arthroscopic rotator cuff repair were reviewed and allocated to isolated SSC (n = 39) and combined anterosuperior tendon tear (n = 71) groups and analyzed. Preoperative clinical testing included belly press (BPT), bear hug (BHT), lift-off (LOT), palm-up (PUT), and Jobe test (JT). All tests were performed in two categories: pain (in 4 categories: 0, 5, 10, and 15) and strength (from 0 to 5). The tendon tears were intraoperatively reviewed and classified. RESULTS: Mean age was 59 years (SD 10). The sensitivity of the BHT was 88.2% and 74.5% for BPT, while specificity was only 41.9% for BHT and 45% for BPT. Sensitivity of JT was 90.5% and 87.5% for PUT, while specificity was only 41% for JT and 28.2% for PUT. A low positive correlation for an intraoperative SSC lesion and the strength of BPT (Spearman rank correlation - 0.425; p value < 0.0001) and the strength of BHT ( - 0.362; p value = 0.001) could be found. With linear regression analysis estimated by ordinary least squares, a correlation between BPT strength and surgical grade of SSC lesion (- 0.528; 95% CI, - 0.923 to - 0.133; pvalue < 0.01) was found. CONCLUSION: The BHT showed a higher sensitivity for a SSC lesion, while the BPT had a higher correlation between preoperative testing, most notably internal rotation strength, and intraoperative surgical grade of the SSC tendon lesion. LEVEL OF EVIDENCE: Level II, Prospective cohort study for Diagnostic tests.

The scissors sign: a provocative test for detecting the leading-edge tear of subscapularis tendon: a diagnostic study.

BACKGROUND: Several physical examination tests and signs have been described to aid in the diagnosis of subscapularis (SSC) tear, but have limitations and variable sensitivity. This study aimed to introduce a novel test for detecting a leading-edge tear of the subscapularis (LETS), the most important tendinous portion of SSC. METHODS: A total of 233 patients who underwent arthroscopic repair for anterior and superior cuff tears between January 2018 to September 2019 were retrospectively reviewed. The provocative test we have coined as the "scissors sign" and the other related clinical tests (i.e., belly press, belly off, Napoleon, lift off, internal rotation lag, bear hug tests) were performed preoperatively. Whether the patient has a LETS or the complete tear of the SSC (CTS) was confirmed by arthroscopic findings. Sensitivity, specificity, and areas under the receiver operating characteristic curve were calculated for each test. RESULTS: In patients who had LETS with or without supraspinatus tear, the scissors sign showed the highest sensitivity (91.4%) with a specificity of 81.6%, positive predictive value (PPV) of 80.2%, and negative predictive value (NPV) of 92.1%. In patients with isolated LETS, the scissors sign also showed the highest sensitivity (90.3%) with a specificity of 81.6%, PPV of 57.1%, and NPV of 96.8%. The scissors sign for the complete tear of the subscapularis (CTS) with or without supraspinatus tear and the isolated CTS had a sensitivity of 73.1 and 75%, respectively. CONCLUSIONS: The scissors sign is a novel provocative test that can be helpful in the diagnosis of subscapularis tears, especially LETS, with its high sensitivity and diagnostic accuracy. In combination with other tests, the scissors sign will be a good screening tool.

Combined clinical test and magnetic resonance imaging have similar diagnostic values in the diagnosis of subscapularis tear.

PURPOSE: The aim of the present study was to compare the diagnostic values of clinical tests and magnetic resonance imaging (MRI) which used for the diagnosis of subscapularis (SSc) tears in the patients who underwent arthroscopic rotator cuff surgery. METHODS: Two-hundred and nine consecutive patients who underwent arthroscopic rotator cuff surgery between 2015 and 2019 were analyzed. The lift-off test, belly-press test and bear-hug test were performed preoperatively. 1.5 T MRI scans of all patients were evaluated for SSc integrity. The diagnostic values of both clinical tests and MRI were calculated. SSc tears were graded according to Fox and Romeo. Arthroscopic findings were used as the gold standard for diagnosis of SSc tears. RESULTS: There were 54 SSc tears accounting for an prevalence of 29%. The BHT showed the greatest sensitivity for both type II-II-IV (73.3%) and all types of (68.5%) SSc tears. The sensitivity and specificity of the combined test and MRI were 91.1-87.2% and 93.3-90.8% in Type II-III-IV SSc tears, respectively, and 81.5-88.6% and 88.9-94.7% in all SSc tears, respectively. There were no statistically significant difference between combined test and MRI in terms of sensitivity and specificity (n.s.). CONCLUSION: The present study is the first that compared both clinical tests and MRI with arthroscopic findings in terms of sensitivity and specificity in the same patient group. A combination of clinical tests increases their diagnostic values and shows similar sensitivity and specificity as MRI. LEVEL OF EVIDENCE: I.

Prediction of the anterior shoulder pain source by detecting indirect signs for partial articular subscapularis tendon tears through conventional magnetic resonance imaging.

PURPOSE: To evaluate the diagnostic efficacy of indirect signs for proximal articular-positioned, partial (< 50%), subscapularis tendon tears (facet 1 tears) via conventional magnetic resonance imaging (MRI). METHODS: A retrospective study was conducted on 67 patients of Yoo's type 1 or 2A tears. Forty-five arthroscopic subacromial decompression and acromioclavicular resection cases served as controls. Indirect signs indicating a facet 1 tear included small defects, superior subscapularis recess (SSR), long head of the biceps (LHBT) configurations, bone edema or cyst formation on lesser tuberosity (LTBEC), and fatty infiltration of subscapularis muscle. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were checked. RESULTS: SSR was the most sensitive sign (90%). The sensitivities and NPV of LHBT configurations and LTBEC were low (sensitivity: 42.9% and 17.9%, NPV: 56.4% and 44.4%, respectively). The specificities of all indirect signs were relatively high (> 90%). The Chi-squared test and multinomial logistic regression confirmed the significance of small defects, SSRs, and fatty infiltrations for facet 1 tears (p ≤ 0.014). The combined sensitivity and specificity were up to 97.7% and 92.3%, respectively, in the presence of either a small defect or an SSR. CONCLUSIONS: Conventional MRI alone can detect facet 1 tears through indirect signs (small defects, SSR, and fatty infiltrations of the subscapularis muscle), predicting unspecified anterior shoulder pain due to concealed biceps instability, and facilitating preoperative diagnosis for a facet 1 tear. LEVEL OF EVIDENCE: III.

Clinical outcomes and temporal changes in the range of motion following superior capsular reconstruction for irreparable rotator cuff tears: comparison based on the Hamada classification, presence or absence of shoulder pseudoparalysis, and status of the subscapularis tendon.

BACKGROUND: Superior capsular reconstruction (SCR) has recently gained popularity as a surgical solution for patients with massive rotator cuff tears or shoulder pseudoparalysis (PPS). Good clinical outcomes have been reported after SCR; however, the factors that influence its clinical outcomes remain unclear. Therefore, in this study, we aimed to clarify the factors influencing postoperative outcomes after SCR using tensor fascia lata graft, for which we evaluated the Hamada grade, patients with or without PPS, and the status of the subscapularis tendon (SSC). METHODS: In total, 54 consecutive patients with irreparable rotator cuff tears or PPS who underwent SCR between June 2014 and October 2018 were included. The enrolled patients were grouped and compared as follows: (1) Hamada grade 2 (11 patients) and Hamada grade 3 (43 patients) and (2) non-PPS (22 patients), moderate PPS (16 patients), and severe PPS (16 patients). For subanalysis, the 32 PPS patients were divided into 3 groups: intact SSC (11 patients), repairable SSC (16 patients), and irreparable SSC (5 patients). To assess shoulder function, the American Shoulder and Elbow Surgeons (ASES) score was evaluated before surgery and at 24 months postoperatively; shoulder range of motion was evaluated at 2, 3, 4, 5, 6, 8, 10, 12, and 24 months postoperatively. RESULTS: No significant differences in postoperative ASES scores and shoulder range of motion were observed between the Hamada grade 2 and grade 3 groups or between the non-PPS, moderate PPS, and severe PPS groups. However, significant differences in postoperative shoulder elevation and ASES scores were observed between the intact SSC and irreparable SSC groups (P = .006) and between the repairable SSC and irreparable SSC groups (P = .003). CONCLUSIONS: This study demonstrated that the status of the SSC, rather than the Hamada grade or the presence or absence of PPS, influences the clinical outcomes after SCR. Therefore, reparability or intactness of the SSC is an important factor in considering the surgical indication for SCR.

A very rare case of an accessory subscapularis muscle and its potential clinical significance.

The subscapularis muscle is the largest muscle of the rotator cuff and its main function is internal rotation. It is morphologically variable in both point of origin and insertion. The presence of an accessory subscapularis muscle can lead to brachial plexus neuropathy. This report presents a very rare accessory subscapularis muscle originating from two distinct bands on the subscapularis and teres major muscles. The insertion was divided among four tendons. The fourth tendon is bifurcated. One of these was connected to the tendon of the subscapularis muscle and the other three inserted into the base of the coracoid process of the scapula. This anomalous muscle has the potential to entrap the nerves of the posterior cord such as the axillary, lower subscapular, and thoracodorsal nerves.

The novel arthroscopic subscapular sling procedure grants better stability than an arthroscopic Bankart repair in a cadaveric study.

PURPOSE: This novel arthroscopic subscapular sling procedure stabilizes the shoulder using a semitendinosus graft to create a sling around the subscapular tendon, which provides both static and dynamic stability. The aim of the study was to evaluate the biomechanical stability of the subscapular sling procedure in human cadaveric shoulders. The hypothesis was that the sling offers an equal stabilizing effect and range of motion compared to an arthroscopic Bankart repair. METHODS: Sixteen shoulders were investigated using an industrial robot-based testing platform and four different conditions: the physiologically intact shoulder, after creating a Bankart lesion, after arthroscopic Bankart repair, and finally after applying the subscapular sling procedure using a semitendinosus tendon graft. Joint translation and external rotation were evaluated for each condition. RESULTS: The results show improved stability in the shoulders with the subscapular sling. The robot testing revealed a significant reduction in translation in anterior and anterior-inferior directions compared to the arthroscopic Bankart repair. None of the shoulders were dislocated by forced manual abduction and external rotation. No difficulties were encountered in performing the arthroscopic subscapular sling procedure. Thorough postoperative anatomical dissection showed no alterations to structures at risk. CONCLUSION: The biomechanical results show increased stability with the use of the subscapular sling method.

Teres major transfer to restore external rotation of shoulder in Erb palsy patients.

BACKGROUND: The lack of external rotation and shoulder abduction as sequelae of obstetric brachial plexus palsy requires a release of the subscapularis muscle associated with tendon transfer of the internal rotator of the shoulder. The aim of this study was to present the results of a teres major transfer to the infraspinatus tendon. METHODS: This study included 20 patients (9 boys and 11 girls) with a mean age of 3 years 8 months (range, 1.5-14 years). The average follow-up time was 42 months (range, 12-48 months) to determine whether external rotation weakness and internal rotation contracture sequelae were managed by anterior release of the subscapularis and teres major tendon transfer to the infraspinatus tendon. RESULTS: We found marked improvement in shoulder abduction from 67° before surgery to 158° after surgery. We also found marked improvements in active external rotation from 8° before surgery to 85° after surgery and in passive external rotation from 0° preoperatively to 72° postoperatively. Two cases showed a loss of the last degrees of internal rotation, but this improved after physiotherapy. CONCLUSIONS: Anterior release of the subscapularis tendon with a teres major transfer to the infraspinatus tendon significantly improves shoulder function in Erb palsy patients with internal rotation contracture.

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.

Histologic characteristics of the subscapularis tendon from muscle to bone: reference to subscapularis lesions.

BACKGROUND: Although subscapularis tendon lesions seem to differ from those of the supraspinatus tendon, the features they have in common suggest that the subscapularis tendon may also have 2 distinct layers. Our aim was therefore to characterize the histologic structure of the subscapularis tendon from its humeral insertion point to the musculotendinous junction. MATERIAL AND METHODS: A histologic study was performed on 10 autopsy samples. The subscapularis tendon was extracted in one piece from the musculotendinous junction to the humeral insertion point and was prepared using standard (hematoxylin-eosin-saffron) staining. RESULTS: Histologic analysis revealed 2 fibrous layers, distinguishable by the orientation of the collagen bundles. The deep layer was thinner and composed of parallel longitudinal collagen fibers inserting onto the lesser tuberosity flush with the cartilage. The superficial layer was thicker and composed of interdigitated collagen bundles inserting onto the lesser and the greater tuberosity after splitting into 2 bands, 1 lining the floor of the bicipital groove, and the other extending over the long head of the biceps tendon across the groove. Each layer formed an independent musculotendinous junction in the subscapularis muscle. CONCLUSIONS: The subscapularis tendon is composed of 2 distinct fibrous layers, just like the supraspinatus tendon, but arranged differently. The superficial layer of the subscapularis tendon passes across the bicipital groove and forms a fibrous ring around the long head of the biceps tendon that stabilizes the latter in the bicipital groove. These results explain some of the specific features of subscapularis tears described in the literature, namely, delamination and biceps subluxation.

The role of the subscapularis tendon in a lateralized reverse total shoulder arthroplasty: repair versus nonrepair.

PURPOSE: The reverse shoulder prost hesis (rTSA) is now implanted by the same percentage of anatomic shoulder prosthesis in the USA. Scapular notching and loss of extrarotation have been underlined as complication at long-term follow-up due to the Grammont design. The current trend to reduce those limits is to position both components lateralized. As the role of the subscapularis tendon in this new rTSA design is unclear, the purpose of this study is to quantify rTSA outcomes in patients with or without subscapularis tendon suture. METHODS: The surgery was performed by the same orthopaedic surgeon (F.F.), using a Aequalis Ascend™ Flex prosthesis (Tornier, Montbonnot, France) with a bone autograft. Forty-four patients underwent surgery with the tendon sutured, whereas 40 patients underwent the same surgery without repairing it. Patients were evaluated pre-operatively and at the last follow-up using Constant score, VAS, and ROM. The minimum and mean follow-ups were six and 16.6 months, respectively. RESULTS: All patients showed statistically significant improvement in pain and joint function following surgery. This study highlighted significant higher values in intrarotation and abduction, respectively, with and without suturing the subscapularis tendon. However, no significant differences were underlined in Constant score, VAS, forward flexion, extrarotation at 0° and 90° of abduction, and rate of instability. CONCLUSIONS: As predicted, significant clinical improvements were observed in both groups with some differences. These clinical results showed that the use of rTSA with lateralized humerus and bony increase offset leads to realistic clinical improvements with a low risk of instability without the need for compression and stabilization of the tendon.

Accuracy of magnetic resonance imaging (MRI) for subscapularis tear: a systematic review and meta-analysis of diagnostic studies.

INTRODUCTION: The accuracy of MRI for subscapularis tear is lower than that of overall rotator cuff tears. Until now, no systematic reviews and meta-analysis have been conducted to compile these data. The purpose of this study was to determine, through a systematic review and meta-analysis, the diagnostic accuracy of MRI in the detection of subscapularis tendon tears. MATERIALS AND METHODS: A systematic review of PubMed, EMBASE, and MEDLINE databases up to April 2017 was performed. All studies assessing the sensitivity and specificity of the MRI (index test) compared to arthroscopic surgical findings (reference test) for subscapularis tendon tear were included. A meta-analysis was performed to calculate pooled sensitivity, specificity, sROC curve, and diagnostic odds ratio values. RESULTS: A total of 497 citations were identified. After applying the eligibility criteria, 14 articles were included, including 1858 shoulders with 613 subscapularis tears. For overall subscapularis tears, sensitivity was 0.68 (95% CI 0.64-0.72) and specificity was 0.90 (95% CI 0.89-0.92). Sensitivity was 0.93 (95% CI 0.83-0.98) for full-thickness tears and 0.74 (95% CI 0.66-0.82) for partial tears. Specificity was 0.97 (95% CI 0.94-0.98) for full-thickness tears and 0.88 (95% CI 0.85-0.91) for partial tears. Analyzing only studies with field of strength ≥ 1.5 T, sensitivity was 0.80 (95% CI 0.76-0.84) and specificity 0.84 (95% CI 0.81-0.87). CONCLUSION: MRI is an accurate method for diagnosing subscapularis tendon tears; however, its accuracy is lower than that of overall rotator cuff tears, due to its lower sensitivity. LEVEL OF EVIDENCE: III, systematic review of Level II and III studies.

More histologic and ultrastructural degenerative signs in the subscapularis tendon and the joint capsule in male patients with shoulder impingement.

PURPOSE: The purpose of the present study was to analyze biopsy samples from the subscapularis tendon and from the joint capsule from male patients with shoulder impingement syndrome (SAIS) and compare them with samples from male patients with post-traumatic recurrent shoulder instability. The hypothesis of the study was that patients with SAIS would have more histologic and ultrastructural degenerative changes in their subscapularis tendon and joint capsule than patients with post-traumatic recurrent shoulder instability. METHODS: Male patients scheduled for surgery, with either subacromial decompression or Bankart reconstruction, were included. Four biopsies from each patient were obtained from the capsule and four from the subscapularis tendon during arthroscopic surgery. The histologic characteristics and the presence of glycosaminoglycans were assessed using the light microscope, and the ultrastructure was assessed using a transmission electron microscope. RESULTS: Eight patients, median age 53 (45-74) years (p < 0.0001), were included in the impingement group, and 12 patients, median age 27 (22-48) years, were included in the instability group. The histologic assessment revealed significantly higher cellularity and total degeneration score in the capsule (p = 0.016 and p = 0.014 respectively) in patients with subacromial impingement compared with the instability patients. The corresponding finding was not made for the subscapularis tendon. The ultrastructural evaluation revealed that the instability patients had more fibrils with a large diameter (indicating less degeneration) in both the subscapularis tendon and the capsule compared with the impingement patients (p < 0.0001). CONCLUSION: Male patients with subacromial impingement have more histologic and ultrastructural degenerative changes in their shoulder compared with patients with post-traumatic recurrent shoulder instability. CLINICAL RELEVANCE: It appears that in patients with subacromial impingement, the whole shoulder joint is affected and not only the subacromial space. It is the opinion of the authors that intra-articular therapeutic injections could be tried more often in these patients. LEVEL OF EVIDENCE: III.

Diagnostic performance of clinical tests for subscapularis tendon tears.

PURPOSE: Tears of the subscapularis (SSC) tendon constitute a diagnostic challenge. The purpose of the present study was to evaluate the diagnostic capabilities of five clinical SSC tests. METHODS: Five established clinical tests were evaluated in 106 consecutive patients prior to shoulder arthroscopy. The tests included the Lift Off Test, Internal Rotation Lag Sign, Belly Press Test, Belly Off Sign, and Bear Hug Test. The integrity of the SSC tendon at surgery was used as the gold standard. Lesions to the SSC were graded according to Fox and Romeo. RESULTS: There were 32 SSC lesions accounting for an incidence of 30.2%. The sensitivity for all tests was 0.66, while the specificity was 0.82. For all tests, positive tests results were found to be dependent on subscapularis integrity (p < 0.001, respectively). The sensitivity for any type of SSC lesion for the Lift Off Test, Internal Rotation Lag Sign, Belly Press Test, Belly Off Sign, and Bear Hug Test was 0.35, 0.41, 0.34, 0.31, and 0.52, respectively. Specificity was found to be 0.98, 0.91, 0.96, 0.97, and 0.85, respectively. If only grade 2-4 tears were analysed, sensitivity was 0.32, 0.42, 0.37, 0.37, and 0.72 and specificity 0.94, 0.86, 0.92, 0.94, and 0.84. A positive correlation was found between the number of positive tests and the severity of the SSC lesions. CONCLUSION: In the present study, the Bear Hug Test was found to have the highest sensitivity of all tests studied, especially for tears of the upper tendon border. It appears advisable to perform more than one clinical subscapularis test to further improve sensitivity. Nevertheless, SSC tears may still escape clinical recognition. Therefore, a high index of suspicion has to be maintained in order not to miss SSC tears. LEVEL OF EVIDENCE: Diagnostic study, Level I.