SSC Tendon Research Articles

Internal rotation resistance test at abduction and external rotation: a new clinical test for diagnosing subscapularis lesions

A new clinical test for evaluating subscapularis (SSC) integrity was described, and its diagnostic value was compared with the present SSC tests (the lift-off, belly-press, IRLS and bear-hug tests). The new test is called internal rotation resistance test at abduction and external rotation (IRRT). The test is performed at maximal 90° of abduction and maximal external rotation. Two hundred and thirty-five consecutive patients suffering from rotator cuff injury were evaluated preoperatively. Six tests were performed to assess the function of the SSC: the lift-off, belly-press, IRLS, the bear-hug, IRRT at 0° abduction and 0° external rotation (IRRT0°) and IRRT at maximal 90° abduction and maximal external rotation (IRRTM). Arthroscopic findings were the reference for diagnosing of SSC lesions. The IRRTM test showed the greatest sensitivity (76.5%), and IRLS (31.6%) test had the lowest sensitivity. The IRRTM had the highest accuracy (79.0%), and lift-off had the lowest accuracy (65.3%). Positive IRRTM, bear-hug, belly-press, IRRT0° tests indicate that about one-third of the SSC is torn, and a positive lift-off and IRLS tests predict a severe tear at least two-thirds of the SSC. The IRRTM represents a sensitive diagnostic test for SSC lesions and improves the chance of finding the upper part of the SSC tears. When the IRRTM is positive, the surgeon should pay particular attention to detecting the SSC tendon during arthroscopy. Diagnostic study, Level I.

Arthroscopic Repair of Large Subscapularis Tendon Tears: 2- to 4-Year Clinical and Radiographic Outcomes

The purpose of this study was to evaluate outcome and structural integrity after arthroscopic repair of large subscapularis tendon (SSC) tears at 2 to 4 years' follow-up. Between January 2006 and October 2008, 52 consecutive patients underwent arthroscopic repair of Lafosse type III and IV SSC ruptures. A total of 46 patients (38 men and 8 women) with a mean age of 62 years (range, 45 to 81 years) were available for final follow-up. Clinical findings were assessed for all patients preoperatively and postoperatively, including range of motion, the lift-off test, the belly-press test, the Constant score, and the modified University of California, Los Angeles score. Subscapularis muscle strength by use of the bear-hug test and external rotation were compared in both shoulders postoperatively. Patients were evaluated with plain radiographs and magnetic resonance imaging or computed tomographic arthrography before surgery. Postoperatively, radiographic examination was completed by use of magnetic resonance imaging or computed tomographic arthrography in 39 patients (85%). Patients completed the subjective shoulder value and rated their satisfaction at final follow-up. The mean follow-up period was 35.3 ± 9.6 months (range, 23 to 57 months). An isolated lesion was detected in 13% of patients; a lesion of the SSC and supraspinatus tendon was found in 37%; and a lesion of the SSC, supraspinatus tendon, and infraspinatus tendon was detected in 50%. At latest follow-up, the mean Constant score significantly improved from 46.4 points to 79.9 points and the modified University of California, Los Angeles score improved from 15.1 points to 31.5 points (P < .001). Subscapularis strength was 92% and external rotation was 96% of the nonoperative shoulder. All outcome scores were similar between Lafosse type III and IV SSC ruptures. Radiographic evaluation showed a rerupture rate of 11%. The coracohumeral distance increased from 9.7 mm to 10.1 mm postoperatively (P= .086). The subjective shoulder value improved from 51% to 88% (P < .001), and 98% of patients were satisfied or very satisfied. Arthroscopic treatment of large to massive SSC ruptures results in significant clinical improvements, excellent maintenance of muscle strength, and durable tendon integrity at 2 to 4 years' follow-up. Level IV, therapeutic case series.

The “bridging sign”: A MR finding for combined full-thickness tears of the subscapularis tendon and the supraspinatus tendon

In daily practice, we discovered one of the secondary magnetic resonance (MR) findings of the subscapularis (SSC) tendon tear, the "bridging sign", which has not been previously described. To describe the "bridging sign" on shoulder MR imaging and its radiological and clinical significance in patients with SSC tendon tear. Twenty-nine patients who had undergone shoulder arthroscopy and had full-thickness tear of the subscapularis tendon were enrolled. The medical records of the 29 patients were retrospectively reviewed for the duration of shoulder pain, rotator cuff tears, and associated arthroscopic findings: biceps tendon abnormality and superior glenoid labral tear. Then, preoperative shoulder MR images were retrospectively reviewed for the presence or absence of the "bridging sign" and associated MR findings: periarticular fluid and fatty atrophy of the supraspinatus and subscapularis muscles. The type of rotator cuff tear associated with the "bridging sign" was assessed and the sensitivity, specificity, and accuracy of the "bridging sign" for the diagnosis of a certain type of rotator cuff tear were calculated. Associated arthroscopic and MR findings and mean duration of the shoulder pain between the patients with and without the "bridging sign" were compared. The "bridging sign" was seen in 17 of 29 patients and corresponded to a complex of the torn and superomedially retracted subscapularis tendon, coracohumeral ligament, and superior glenohumeral ligament, adhered to the anterior margin of the torn supraspinatus (SSP) tendon on arthroscopy. All patients with the "bridging sign" had combined full-thickness tear (FTT) of the cranial 1/2 portion of the subscapularis tendon and anterior 1/2 portion of the SSP tendon. The sensitivity, specificity, and accuracy of the "bridging sign" for the diagnosis of combined FTTs of the SSC tendon and anterior portion of the SSP tendon were 81.0%, 100%, and 86.2%, respectively. The patients with the "bridging sign" had longer duration of shoulder pain and more frequent associated arthroscopic and MR findings than the patients without the "bridging sign". The "bridging sign" is a highly specific finding for combined full-thickness tears of the subscapularis tendon and anterior portion of the supraspinatus tendon, associated with more chronic shoulder pain and more sever rotator cuff tear.

Diagnostic values of clinical tests for subscapularis lesions

Subscapularis (SSC) lesions are often underdiagnosed in the clinical routine. This study establishes and compares the diagnostic values of various clinical signs and diagnostic tests for lesions of the SSC tendon. Fifty consecutive patients who were scheduled for an arthroscopic subacromial or rotator cuff procedure were clinically evaluated using the lift-off test (LOT), the internal rotation lag sign (IRLS), the modified belly-press test (BPT) and the belly-off sign (BOS) preoperatively. A modified classification system according to Fox et al. (Type I-IV) was used to classify the SSC lesion during diagnostic arthroscopy. SSC tendon tears occurred with a prevalence of 30% (15 of 50). Five type I, six type II, three type IIIa and one type IIIb tears according to the modified classification system were found. Fifteen percent of the SSC tears were not predicted preoperatively by using all of the tests. In six cases (12%), the LOT and the IRLS could not be performed due to a painful restricted range of motion. The modified BPT and the BOS showed the greatest sensitivity (88 and 87%) followed by the IRLS (71%) and the LOT (40%). The BOS had the greatest specificity (91%) followed by the LOT (79%), mod. BPT (68%) and IRLS (45%). The BOS had the highest overall accuracy (90%). With the BOS and the modified BPT in particular, upper SSC lesions (type I and II) could be diagnosed preoperatively. A detailed physical exam using the currently available SSC tests allows diagnosing SSC lesions in the majority of cases preoperatively. However, some tears could not be predicted by preoperative assessment using all the tests.

Autogenous bone grafting for chronic anteroinferior glenoid defects via a complete subscapularis tenotomy approach

Open reconstruction of severe anteroinferior chronic glenoid defects via a complete subscapularis (SSC) tenotomy using a tricortical iliac crest bone grafting technique has been reported. The purpose of this study was to evaluate the clinical and radiological results in patients who underwent this procedure and to investigate the influence of the anterior approach on the structure and function of the SSC musculotendinous unit. Ten patients (two women/eight men, mean age 28.7 years) underwent reconstruction of significant chronic glenoid defects in cases of recurrent shoulder instability with significant glenoid bone loss, using a tricortical autogenous iliac crest in combination with a capsulolabral repair. The patients were followed up clinically (clinical SSC tests and signs, Constant score, Rowe score, Walch-Duplay score, WOSI, MISS), by standard radiographs (true a/p, axillary and glenoid profile view), computed tomography (graft integration, inferior glenoid area) and bilateral magnetic resonance imaging [SSC tendon integrity, cross sectional area, defined muscle diameters and signal intensity analysis (ratio ISP/upper SSC and ISP/lower SSC)]. After a mean follow-up of 37.9 months, the mean Constant score averaged 88.3 points, the Rowe score 89.5 points, the Walch-Duplay score 83.5 points, the MISS 80.6 points and the WOSI 82.6%. No recurrent subluxations or dislocations were observed. Clinical signs for SSC insufficiency were present in 80% of cases. Two patients had grade I and one patient grade II osteoarthritis according to Samilson and Prieto classification. CT imaging revealed a consolidated autograft in all cases with an 18.4% increase of the inferior glenoid area postoperatively (P < 0.05). No tendon ruptures were found. MR imaging revealed muscular atrophy (P < 0.05) and fatty infiltration of the SSC (P > 0.05) muscle compared to the contralateral side. Open reconstruction of anteroinferior chronic glenoid defects via a complete SSC tenotomy using an iliac crest bone grafting technique allows an anatomic reconstruction of the anteroinferior glenoid with good and excellent clinical results. The anterior approach may lead to atrophy and fatty infiltration of the SSC muscle despite an intact tendon. However, this did not affect the results in terms of stability.