Tears in the subscapularis tendon: descriptive analysis and results of surgical repair

Quantitative MRI indicators and features for partial subscapularis tendon tears on conventional shoulder MRI

Background

Diagnosing partial subscapularis (SSC) tendon tears still faces challenges. A failure rate of massive posterosuperior rotator cuff tear repair will be highly increased when extending more than one-third of SSC tendon. This study aims to investigate the quantitative indicators and features of partial SSC tears on conventional shoulder MRI and improve the preoperative diagnostic accuracy.

Materials and methods

Four hundred and thirty-seven patients underwent MRI and arthroscopy were retrospectively reviewed; 89 patients with partial SSC tears in case group and 50 patients with normal SSC in control group were included. Six MRI features with the explicit definition of some quantitative indicators were evaluated.

Results

Fissure sign showed the highest diagnostic efficiency for the partial SSC tears, with a specificity of 92%, sensitivity of 75.3%, and accuracy of 81.3%. Thinning of SSC, fluid collection under the coraco-glenoid arch (CGA), and combined SSP complete tear also showed high specificity of 86%, 80%, and 80%, respectively, while the sensitivity and accuracy were moderate, with a sensitivity of 38.2%, 50.6%, and 48.3%, respectively, an accuracy of 55.4%, 61.2%, and 59.7%, respectively. The specificity, sensitivity, and accuracy of lesser tuberosity cysts were all moderate with values of 68%, 56.2%, and 60%, respectively. However, fat accumulation under the CGA showed no significant difference between the partial SSC tears group and the control group.

Conclusion

Several specific MRI features with quantitative indicators defined in this study can be used to improve the accuracy of preoperative MRI diagnosis of partial SSC tears.

Zimmer Z, Gilotra MN. Reliability, validity, and responsiveness of a novel subscapularis outcome score: The Baltimore Orthopedic Subscapularis Score

Background

Available surveys that evaluate shoulder strength and pain often combine rotator cuff muscles making the test unable to differentiate subscapularis tears from other pathology including concomitant supraspinatus, infraspinatus tears. The purpose of this study was to validate a subscapularis-specific shoulder survey (Baltimore Orthopedic Subscapularis Score) as a viable clinical outcome assessment through analysis of psychometric properties.

Methods

A 5-question survey was given to a study population of 390 patients, 136 of whom had full thickness rotator cuff tears with a minimum score of 5 (better) and a maximum score of 25 (worse). Surveys were given during the initial consultation, preoperative visit, and postoperative visit. Content validity, construct validity, test-retest reliability, responsiveness to change, internal consistency, and minimal clinically important difference using distribution and anchor-based methods were determined for our subscapularis function survey.

Results

A high correlation was reported on test-retest reliability (intraclass correlation coefficient = 0.89). An acceptable internal consistency was reported for all patients surveyed (Cronbach alpha = 0.91). Floor and ceiling effects for patients with rotator cuff pathology were minimized (1% for both). Patients with an isolated subscapularis tear scored worse than supraspinatus/infraspinatus tears and exhibited similar dysfunction as patients with a supraspinatus/infraspinatus/subscapularis tear. An acceptable construct validity was reported with subscapularis-involved tears demonstrating higher scores with significance (P < .05). There was excellent responsiveness to change with a standardized response mean of 1.51 and effect size of 1.27 (large > 0.8). The minimal clinically important difference using a distribution and anchor-based method was 4.1 and 4.6, respectively. Among patients with rotator cuff tears in this population, a score of 22 or higher predicts a subscapularis tear 75% of the time, in spite of its low overall prevalence.

Conclusion

The subscapularis shoulder score demonstrated acceptable psychometric performance for outcomes assessment in patients with rotator cuff disease. This survey can be used as an effective clinical tool to assess subscapularis function.

Current concepts review in the management of subscapularis tears

Subscapularis (SSc) is the prime internal rotator of shoulder. It is the most powerful rotator cuff muscle, maintaining the anterior force couple of shoulder. The tears in SSc as any other rotator cuff muscles might result from a traumatic event or more commonly from intrinsic degeneration. With the advent and widespread use of shoulder arthroscopy, SSc tears, which were once considered as "forgotten or hidden lesions" are now being increasingly recognized. Isolated SSc tears are relatively rare. They occur in combinations. Clinically internal rotation can be near normal because of the compensation provided by other internal rotators. It is not uncommon for patients with SSc tear to be normal on routine physical examination. The Bear Hug test (BHT) has high sensitivity and accuracy in the diagnosis of SSc tear. The combined use of BHT with Belly Press Test has been found optimal for diagnosis. US is an accurate and reliable method for diagnosing SSc tears and outperformed MRI in diagnosing partial-thickness SSc tears. The MRI is currently the most advanced imaging available for diagnosis. The specificity is up to 100%. However, the sensitivity is between 36 and 40%. The earliest classification system for SSc tears was by Fox et al. The commonly used classification is by Lafosse et al. The recent system by Yoo et al. is based on the insertion of SSc. The comma sign is gaining importance not only in arthroscopic diagnosis but also in MRI identification and repair of SSc. The mode of management is mainly arthroscopic. The techniques of repair of SSc are continuously progressing. However, there is no clear consensus on the double vs single-row repairs, biceps tendon management, and the role of coracoplasty. Future research must focus on these areas. Reserve shoulder arthroplasty is reserved for salvage in older age groups. Tendon transfers are performed in young active individuals with irreparable tears.

Biomechanical analysis of latissimus dorsi, pectoralis major, and pectoralis minor transfers in subscapularis-deficient shoulders

BACKGROUND

Irreparable subscapularis (SSc) tears alter the dynamic force coupling of the shoulder, resulting in pain, weakness, and impaired shoulder function. Pectoralis major (Pma), pectoralis minor (Pmi), and latissimus dorsi (LD) transfers are treatment options for irreparable SSc tears, but clinical outcomes vary. The purpose of this study was to compare the biomechanical properties of Pma, Pmi, and LD transfers in an SSc-deficient shoulder using a computational model.

METHODS

A computer shoulder model was used to investigate the moment arms of Pma, Pmi, and LD tendon transfers compared with an intact SSc. Nine computed tomography scans from subjects without osteoarthritis were used. Virtual Pma, Pmi, and LD transfers were performed to the upper border of the SSc insertion site on the lesser tuberosity of the humerus. Muscle moment arms were computed for functional motions of 0°-80° of internal rotation with the arm in 20° and 90° of shoulder abduction and 0°-150° of shoulder abduction. The results were compared with those of the native SSc moment arms. A repeated-measures analysis of variance was then performed to determine significant differences.

RESULTS

Internal rotation moment arms of the transferred Pma and Pmi decreased significantly after 30° and 40° of internal rotation compared with the SSc moment arm of the intact shoulder, whereas the moment arm of LD transfer more closely mimicked that of the native SSc through 0°-80° of internal rotation. All 3 tendon transfer configurations demonstrated weak abductive moment arms (7.6-8.0 mm), comparable to the intact SSc (7.8 mm) but significantly lower than the intact adductive moment arms of the native Pma and LD (26.8 mm and 28.2 mm, respectively).

CONCLUSION

LD transfer most closely approximates the native SS regarding internal rotation moment arms. However, LD transfer also showed a reduction in adductive moment arms.

Injuries in Muscle-Tendon-Bone Units: A Systematic Review Considering the Role of Passive Tissue Fatigue

Background:

Low-cycle fatigue damage accumulating to the point of structural failure has been recently reported at the origin of the human anterior cruciate ligament under strenuous repetitive loading. If this can occur in a ligament, low-cycle fatigue damage may also occur in the connective tissue of muscle-tendon units. To this end, we reviewed what is known about how, when, and where injuries of muscle-tendon units occur throughout the body.

Purpose:

To systematically review injuries in the muscle-tendon-bone complex; assess the site of injury (muscle belly, musculotendinous junction [MTJ], tendon/aponeurosis, tendon/aponeurosis–bone junction, and tendon/aponeurosis avulsion), incidence, muscles and tendons involved, mechanism of injury, and main symptoms; and consider the hypothesis that injury may often be consistent with the accumulation of multiscale material fatigue damage during repetitive submaximal loading regimens.

Methods:

PubMed, Web of Science, Scopus, and ProQuest were searched on July 24, 2019. Quality assessment was undertaken using ARRIVE, STROBE, and CARE (Animal Research: Reporting In Vivo Experiments, Strengthening the Reporting of Observational Studies in Epidemiology, and the Case Report Statement and Checklist, respectively).

Results:

Overall, 131 studies met the inclusion criteria, including 799 specimens and 2,823 patients who sustained 3,246 injuries. Laboratory studies showed a preponderance of failures at the MTJ, a viscoelastic behavior of muscle-tendon units, and damage accumulation at the MTJ with repetitive loading. Observational studies showed that 35% of injuries occurred in the tendon midsubstance; 28%, at the MTJ; 18%, at the tendon-bone junction; 13%, within the muscle belly and that 6% were tendon avulsions including a bone fragment. The biceps femoris was the most injured muscle (25%), followed by the supraspinatus (12%) and the Achilles tendon (9%). The most common symptoms were hematoma and/or swelling, tenderness, edema and muscle/tendon retraction. The onset of injury was consistent with tissue fatigue at all injury sites except for tendon avulsions, where 63% of the injuries were caused by an evident trauma.

Conclusion:

Excluding traumatic tendon avulsions, most injuries were consistent with the hypothesis that material fatigue damage accumulated during repetitive submaximal loading regimens. If supported by data from better imaging modalities, this has implications for improving injury detection, prevention, and training regimens.

Analysis of the results and adverse factors of arthroscopic repair of degenerative subscapular lesions

OBJECTIVE

To carry out a review of degenerative subscapularis ruptures (SSC) after their arthroscopic repair and to evaluate whether the results are comparable in terms of pain and function to those of younger patients with traumatic ruptures.

METHODS

The data of 80 SSC tears of the 660 rotator cuff tears operated on by the same team of surgeons from June 2008 to June 2018 were retrospectively reviewed. The clinical data of the surgical indications were collected: age, gender, laterality, intervention delay, associated pathologies, location of pain, value of the Visual Analogue Scale (VAS) and the Constant-Murley test (CMT); surgical data were also collected: type and size of lesion, associated biceps injury and associated surgical procedure, coracoid stenosis and associated surgical procedure, number and type of anchors used. A statistical study was performed with multiple linear regression test, parametric tests (Student's t or ANOVA) and non-parametric tests.

RESULTS

Of 80 patients, 36 were women (45%) and 44, men (55%); mean age 61years (range 47 to 81); mean delay of surgery 3.5months (range 1 to 6); right shoulder affected in 46 cases (57.5%), left in 34 (42.5%); 22 (27.5%) were isolated lesions, 58 (72.5%) were associated with supraspinatus rupture (SE). The mean improvement was 5.0 points in terms of the VAS and 39.9 points on average in the CMT. New breakage rate, 1.25%. Adverse factors: size of the tear, delay in intervention, women. Patients with type I-B rupture have a better overall result in the CMT than types I-A and III. The longer the delay, the worse results are observed, both for the VAS and the CMT. Women present worse and statistically significant results both in the VAS (P=.00) and in the CMT (P=.01).

CONCLUSIONS

Excellent and good results have been obtained in this group of patients, but there are adverse factors such as the size of the tear, the duration of the symptoms and the association of other pathologies, especially in women.

Can a simple fall cause a rotator cuff tear? Literature review and biomechanical considerations

PURPOSE

A simple fall on the shoulder is often referred to as minor trauma that cannot cause a tendon tear but at best reveal a pre-existing rotator cuff pathology. We wanted to know whether this statement was true. The purpose of our study was therefore to summarize the causes of acute rotator cuff tears reported in the literature and provide a biomechanical explanation for tendon tears diagnosed after a fall.

METHOD

We searched PubMed and included studies reporting rotator cuff tears occurring due to a trauma. The number of cases, the tendons involved, the age of the patients, and the nature of trauma were summarized. In addition, we noted any information provided by the authors on the pathogenesis of acute tendon ruptures.

RESULTS

Sixty-seven articles with a total of 4061 traumatic rotator cuff tears met the inclusion criteria. A simple fall was the most common cause (725 cases) and the supraspinatus tendon was most frequently affected. The postulated pathomechanism is a sudden stretch of the tendon-muscle unit while contracting (eccentric loading).

CONCLUSION

A simple fall can cause an acute rotator cuff tear and fall-related tears are not restricted to young individuals. They can affect patients of any age. The stresses occurring within the rotator cuff during an attempt to cushion a fall may locally exceed the tensile strength of the tendon fibers and cause a partial or full-thickness tear.

Retrospective review of open and arthroscopic repair of anterosuperior rotator cuff tears with subscapularis involvement: a single surgeon's experience

BACKGROUND

There have been conflicting results when comparing outcomes of open vs. arthroscopic anterosuperior rotator cuff repairs with subscapularis involvement. The purpose of this study was to evaluate midterm outcome differences and complications following open vs. arthroscopic repair of rotator cuff tears involving the subscapularis by a single surgeon.

METHODS

This was a retrospective review of 57 rotator cuff repairs involving the subscapularis performed by a single surgeon over a 10-year period. During this time, the surgeon transitioned from open to arthroscopic repair. Preoperative and postoperative range of motion, lift-off test, belly press test, and American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment form scores were measured.

RESULTS

Eighteen patients had open procedures and 39 had arthroscopic repair. The mean preoperative ASES score for the open group was 39 and postoperatively was 79. The mean preoperative ASES score for the arthroscopic group was 44 and improved to 80 postoperatively. There was no significant difference in score or change in score between the 2 groups (P > .05). There was only 1 complication. It occurred in the open group and was a superficial wound dehiscence.

CONCLUSIONS

This study demonstrated no outcome differences between open and arthroscopic rotator cuff repair involving the subscapularis, even with large subscapularis tears. Both techniques significantly improved shoulder function. Arthroscopic and open rotator cuff repairs including the subscapularis are relatively safe procedures, and either technique is an acceptable option.

Prevalence and risk factors for development of subscapularis and biceps pathology in shoulders with degenerative rotator cuff disease: a prospective cohort evaluation

BACKGROUND

The prevalence of subscapularis and long head of biceps (LHB) in relation to the presence and severity of posterosuperior (PS) rotator cuff disease is not known.

METHODS

Subjects with asymptomatic rotator cuff tears were enrolled for this prospective longitudinal study (n = 354) and followed annually with shoulder ultrasonography and clinical evaluations to assess for the presence of subscapularis, LHB, and PS rotator cuff pathology and pain development.

RESULTS

Subscapularis pathology developed in 14% of shoulders over a median follow-up of 5 years, with partial-thickness tearing occurring most commonly (83%). Age, sex, and hand dominance were not associated with subscapularis pathology. A greater proportion of concomitant full-thickness PS cuff tears were observed in shoulders that developed subscapularis tears (76% vs. 50%, P = .002). The PS cuff tear width (10 mm vs. 14 mm, P = .01) at the time of enrollment and both tear width (10 mm vs. 15 mm, P = .003) and length (12 mm vs. 15.5 mm, P = .02) at the time of diagnosis of subscapularis pathology were greater in subscapularis-torn shoulders. LHB pathology was prevalent in 34% of shoulders, with dislocation/subluxation occurring in 63% and higher prevalence in subscapularis-torn shoulders (71% vs. 12%, P < .01). Subscapularis-torn shoulders were more likely to develop pain (67% vs. 45%, P = .004), and concomitant PS cuff tear enlargement was associated with greater risk for pain development (76% vs. 36%, P = .01).

CONCLUSIONS

The development of subscapularis and LHB pathology is significantly related to the size of the PS cuff tear. Subscapularis involvement is associated with greater risk of pain development in degenerative rotator cuff disease.

Subscapularis tears: hidden and forgotten no more

The subscapularis tendon, at one point, was thought of as the forgotten tendon, with “hidden lesions” that referred to partial tears of this tendon. Better understanding of anatomy and biomechanics combined with improved imaging technology and the widespread use of arthroscopy has led to a higher rate of subscapularis tear diagnoses and repairs.

The bulk mass of the subscapularis muscle is more than that of all 3 other rotator cuff muscles combined. It functions as the internal rotator of the shoulder as the stout, rolled border of its tendon inserts onto the superior portion of the lesser tuberosity. A thorough history combined with specific physical examination maneuvers (including the bear hug, lift-off, and belly-press tests) is critical for accurate diagnosis. A systematic approach to advanced shoulder imaging also improves diagnostic capacity.

Once identified, most subscapularis tendon tears can be successfully repaired arthroscopically. The Lafosse classification is useful as part of a treatment algorithm. Type I and II tears may be addressed while viewing from the standard posterior glenohumeral portal; larger Lafosse type III and IV tears are best repaired with anterior visualization at the subacromial or subdeltoid space. Tendon mobilization for larger tears is critical for adequate repair.

In Lafosse type V tears, in which there is glenohumeral imbalance, tendon transfers and reverse replacement are commonly considered salvage options.

Multi-modal imaging of the subscapularis muscle

Abstract

The subscapularis (SSC) muscle is the most powerful of the rotator cuff muscles, and plays an important role in shoulder motion and stabilization. SSC tendon tear is quite uncommon, compared to the supraspinatus (SSP) tendon, and, most of the time, part of a large rupture of the rotator cuff. Various complementary imaging techniques can be used to obtain an accurate diagnosis of SSC tendon lesions, as well as their extension and muscular impact. Pre-operative diagnosis by imaging is a key issue, since a lesion of the SSC tendon impacts on treatment, surgical approach, and post-operative functional prognosis of rotator cuff injuries. Radiologists should be aware of the SSC anatomy, variability in radiological presentation of muscle or tendon injury, and particular mechanisms that may lead to a SSC injury, such as coracoid impingement.

Teaching Points

• Isolated subscapularis (SSC) tendon tears are uncommon.

• Classically, partial thickness SSC tendon tears start superomedially and progress inferolaterally.

• Long head of biceps tendon medial dislocation can indirectly signify SSC tendon tears.

• SSC tendon injury is associated with anterior shoulder instability.

• Dynamic ultrasound study of the SSC helps to diagnose coracoid impingement.

Lesser tuberosity avulsions in adolescents

BACKGROUND

Subscapularis tendon avulsions of the lesser tuberosity are relatively rare and often missed acutely and their characteristic appearance is frequently not recognized or is misinterpreted for an osteochondroma or a neoplastic process.

QUESTIONS/PURPOSES

This report reviews our experience with six adolescents who had subscapularis tendon avulsions of the lesser tuberosity.

METHODS

Six male adolescents (12-15 years) presented with shoulder pain following history of trauma during amateur sport. Clinical notes including range of motion, strength tests, and pain assessment were reviewed along with imaging studies pre- and post treatment. Treatment consisted of either surgical or conservative measures.

RESULTS

Two of the six patients had a large avulsion that simulated an exostosis of the proximal humerus that was misdiagnosed as an osteochondroma at two different outside institutions. All six cases were diagnosed with subscapularis tendon avulsion of the lesser tuberosity following clinical and imaging evaluation at our institution. Five of the patients underwent surgical repair and fixation of the tendon and the lesser tuberosity with suture anchors. One patient was treated conservatively. All patients had a good outcome with recovery of full shoulder strength and motion upon follow-up.

CONCLUSION

Clinicians should have a high index of suspicion of lesser tuberosity avulsions in adolescents who present with loss of internal rotation and anterior shoulder pain following traumatic injuries. In addition, an osseous fragment or exostosis along the inferomedial humeral head should suggest a subscapularis tendon avulsion and also should not be confused with an osteochondroma or a neoplastic process.

The influence of partial subscapularis tendon tears combined with supraspinatus tendon tears

BACKGROUND

With the advent of arthroscopy, more partial subscapularis tears are being recognized. The biomechanical effects of partial subscapularis tears are unknown, and there is no consensus as to their treatment. Therefore, the objective of this study was to evaluate and to quantify the changes in range of motion and glenohumeral kinematics for isolated subscapularis partial tears, combined subscapularis and supraspinatus tears, supraspinatus repair, and combined supraspinatus and subscapularis repair.

METHODS

Six cadaveric shoulders were tested in the scapular plane with 0°, 30°, and 60° shoulder abduction under 6 conditions: intact; ¼ subscapularis tear; ½ subscapularis tear; ½ subscapularis and complete supraspinatus tear; supraspinatus repair; and supraspinatus and subscapularis repair. Maximum internal and external rotation and glenohumeral kinematics were measured under physiologic muscle loading condition. A repeated measures analysis of variance with a Tukey post hoc test was used for statistical analysis.

RESULTS

Maximum external rotation was significantly increased after ¼ subscapularis tear at 30° abduction and in all abduction angles with ½ subscapularis tear (P < .05). The 2 repair conditions did not restore external rotation to the intact level. At maximum internal and external rotation, there was a significant superior shift in the humeral head apex position with ¼ subscapularis tear at 30° abduction and with ½ subscapularis tear at 60° abduction (P < .05). Repair of the supraspinatus tendon partially corrected abnormal kinematics; however, neither repair restored abnormal kinematics to intact.

CONCLUSION

Additional repair of the partial subscapularis tear with supraspinatus tear did not affect external rotation or glenohumeral kinematics. Further studies are needed to evaluate different subscapularis repair techniques.

LEVEL OF EVIDENCE

Basic science study, biomechanics.

Fracture of the coracoid process with acute subscapularis tear without shoulder dislocation

Coracoid process fracture is an uncommon injury and can be easily missed. An associated acute subscapularis tear is still rare. Herein, we describe a 61 year old male who fell from a 2 meter height (stair case) and presented with isolated coracoid process fracture with acute subscapularis tear without dislocation of (R) shoulder joint. The plain x-rays, CT scan and MR arthrography comprised the diagnosis. He was operated upon with reattachment of subscapularis to lesser tuberosity and conjoint tendons to pectoralis major. At 6 mo followup he had good range of motion and his MRI revealed complete healing.

Time to surgery in acute rotator cufftear: A systematic review

Aims

We performed a systematic review of the literature to determine whether earlier surgical repair of acute rotator cuff tear (ARCT) leads to superior post-operative clinical outcomes.

Methods

The MEDLINE, Embase, CINAHL, Web of Science, Cochrane Libraries, controlled-trials.com and clinicaltrials.gov databases were searched using the terms: ‘rotator cuff’, or ‘supraspinatus’, or ‘infraspinatus’, or ‘teres minor’, or ‘subscapularis’ AND ‘surgery’ or ‘repair’. This gave a total of 15 833 articles. After deletion of duplicates and the review of abstracts and full texts by two independent assessors, 15 studies reporting time to surgery for ARCT repair were included. Studies were grouped based on time to surgery < 3 months (group A, seven studies), or > 3 months (group B, eight studies). Weighted means were calculated and compared using Student’s t-test.

Results

Group B had a significantly higher pre-operative Constant score (CS) (p < 0.001), range of movement in external rotation (p = 0.003) and abduction (p < 0.001) compared with group A. Both groups showed clinical improvement with surgical repair; group A had a significantly improved Constant score, University of California, Los Angeles (UCLA) shoulder score, abduction and elevation post-operatively (all p < 0.001). Group B had significantly improved Constant score (p < 0.001) and external rotation (p < 0.001) post-operatively. The mean Constant score improved by 33.5 for group A and by 27.5 for group B.

Conclusion

These findings should be interpreted with caution due to limitations and bias inherent to case-series. We suggest a trend that earlier time to surgery may be linked to better Constant score, and active range of movement in abduction and elevation. Additional prospective studies are required.

A Concise and Comprehensive Description of Shoulder Pathology and Procedures: The 4D Code System

Background. We introduce a novel description system of shoulder pathoanatomy. Its goal is to provide a comprehensive three-dimensional picture, with an additional component of time; thus, we call it the 4D code. Methods. Each line of the code starts with right versus left and a time designation. The pillar components are recorded regardless of pathology; they include subscapularis, long head of biceps tendon, supraspinatus, infraspinatus, and teres minor. Secondary elements can be added if there is observed pathology, including acromioclavicular joint, glenohumeral joint, labrum, tear configuration, location and extent of partial cuff tear, calcific tendonitis, fatty infiltration, and neuropathy. Results. We provide two illustrative examples of patients which show the ease and effectiveness of the 4D code. With a few simple lines, significant amount of information about patients' pathology, surgery, and recovery can be easily conveyed. Discussion. We utilize existing validated classification systems for parts of the shoulder and provide a frame work to build a comprehensive picture. The alphanumeric code provides a simple language that is universally understood. The 4D code is concise yet complete. It seeks to improve efficiency and accuracy of the communication, documentation, and visualization of shoulder pathology within individual practices and between providers.

Does open repair of anterosuperior rotator cuff tear prevent muscular atrophy and fatty infiltration?

BACKGROUND

Repair of cuff tears involving rotator interval reportedly improves function. However, it is unclear whether successful repair prevents shoulder degenerative changes.

QUESTIONS/PURPOSES

Therefore, we (1) documented the minimal 4-year function of patients who underwent open surgical repair for rotator interval tears; (2) evaluated repaired tendon healing with postoperative MRI; and (3) sought to determine the influence of tendon healing on muscular and glenohumeral joint changes.

METHODS

We retrospectively analyzed 22 patients (23 shoulders) treated by open transosseous reinsertion of supraspinatus and subscapularis tendons. The mean age of the patients was 53 years (range, 37-64 years). The tear was traumatic in four cases. Repair healing and muscular changes were assessed using MRI. The minimum followup was 46 months (mean, 75 months; range, 46-103 months).

RESULTS

We observed an improvement in the absolute Constant-Murley score from 63 points preoperatively to 76 points postoperatively. With the last followup MRI, the supraspinatus tendon repair had failed in two of the 23 shoulders, whereas the subscapularis tendon repair had healed in all cases. Once healing of the repaired tendon occurred, supraspinatus muscle atrophy never worsened. However, on MRI fatty infiltration of the rotator cuff muscles increased despite successful tendon repair. Glenohumeral arthritis remained stable. Postoperative abduction and internal rotation strengths were better when the standardized supraspinatus muscle area was greater than 0.5 at the final evaluation.

CONCLUSION

Durable functional improvement and limited degenerative articular and muscular changes can be expected in most patients 4 to 10 years after open repair of anterosuperior cuff tears provided that healing of the cuff is obtained.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The subscapularis: anatomy, injury, and imaging

The subscapularis is the largest and most powerful of the rotator cuff muscles and fulfills an important role in glenohumeral movement and stability. The spectrum and implications of subscapularis muscle or tendon injury differ from injury to other rotator cuff components because of its unique structure and function. Diagnosing subscapularis injury is clinically difficult and assessment of subscapularis integrity may be limited during arthroscopy or open surgery. Diagnostic imaging plays an important part in diagnosing and evaluating the extent of subscapularis injury. The radiologist should be aware of the anatomy of the subscapularis, the variations in muscle or tendon injury, and the potential implications for treatment and prognosis.

After rotator cuff tears, the remaining (intact) tendons are mechanically altered

Although presumed, damage in the remaining (intact) rotator cuff tendons in the presence of an isolated supraspinatus tendon tear or multiple tendon tear has not been well studied. This study used an animal model of multiple rotator cuff tendon tears to investigate alterations in the remaining (intact) tendon mechanical properties at 4 and 8 weeks after injury. Twenty-four rats served as uninjured controls, whereas 72 were divided among 3 tendon detachment groups: supraspinatus tendon detachment, supraspinatus + infraspinatus tendon detachment, and supraspinatus + subscapularis tendon detachment. The remaining (intact) rotator cuff tendons had decreased mechanical properties in the presence of rotator cuff tears. The remaining (intact) subscapularis and infraspinatus tendon cross-sectional areas increased, whereas tendon modulus decreased after tears of both 1 and 2 tendons. The remaining (intact) tendon cross-sectional areas continued to increase with time after injury. These alterations could potentially lead to further tendon damage and tear progression.

Traumatic anterosuperior rotator cuff tears: the outcome of open surgical repair

BACKGROUND

Anterosuperior rotator cuff tears involving the subscapularis and supraspinatus tendons are less common than posterosuperior tears and are rarely discussed in the literature. The purpose of this study was to identify the unique features of this injury and to assess the outcome of operative treatment.

METHODS

Thirty consecutive patients, with a mean age of fifty-seven years (range, forty-three to seventy-three years), had an open repair of a traumatic anterosuperior rotator cuff tear. Twenty-four patients (80%) were male. Sixteen patients (53%) had involvement of the dominant shoulder, twenty-three (77%) had a biceps tendon disorder, and sixteen (53%) had a positive lift-off maneuver prior to surgery. Surgical approaches included an isolated superior deltoid-splitting approach in twenty patients, an isolated deltopectoral approach in five patients, and a combined approach in five patients. Open repair was performed at a mean of 4.5 months after the injury or the onset of symptoms. The final outcomes were determined with a physical examination and patient self-assessed outcome tools.

RESULTS

At a mean follow-up of fifty-six months, twenty-one of the thirty patients were satisfied with their symptoms, and twenty-nine would have the surgery again. The mean pain score on the visual analog scale improved from 6.2 to 1.2 (p < 0.001). The mean score on the Disabilities of the Arm, Shoulder and Hand questionnaire improved from 41.7 to 12.2 (p < 0.001). The mean percentage of functions that patients were able to perform on the Simple Shoulder Test improved from 36.4% to 82.8% (p < 0.001). The mean age and sex-adjusted Constant score was 93.4 postoperatively. The mean elevation, external rotation, and internal rotation of the involved shoulders were 97%, 109%, and 97%, respectively, of those of the contralateral side. The mean strength of elevation, external rotation, and internal rotation were 85%, 93%, and 101%, respectively, of those of the contralateral side. Infraspinatus involvement (p = 0.04), the extent of the supraspinatus tear (p = 0.03), and a Workers' Compensation claim (p = 0.03) were associated with worse outcomes and decreased satisfaction.

CONCLUSIONS

Patients with a traumatic anterosuperior rotator cuff tear present with internal rotation weakness, and they usually have a biceps tendon disorder. While larger tears involving greater portions of the supraspinatus and extending into the infraspinatus are associated with poorer outcomes, early recognition of this injury and open repair can reliably restore shoulder function to near normal levels.

MR Imaging of Rotator Cuff Injury: What the Clinician Needs to Know

The rotator cuff muscles generate torque forces to move the humerus while acting in concord to produce balanced compressive forces to stabilize the glenohumeral joint. Thus, rotator cuff tears are often associated with loss of shoulder strength and stability, which are crucial for optimal shoulder function. The dimensions and extent of rotator cuff tears, the condition of the involved tendon, tear morphologic features, involvement of the subscapularis and infraspinatus tendons or of contiguous structures (eg, rotator interval, long head of the biceps brachii tendon, specific cuff tendons), and evidence of muscle atrophy may all have implications for rotator cuff treatment and prognosis. Magnetic resonance imaging can demonstrate the extent and configuration of rotator cuff abnormalities, suggest mechanical imbalance within the cuff, and document abnormalities of the cuff muscles and adjacent structures. A thorough understanding of the anatomy and function of the rotator cuff and of the consequences of rotator cuff disorders is essential for optimal treatment planning and prognostic accuracy. Identifying the disorder, understanding the potential clinical consequences, and reporting all relevant findings at rotator cuff imaging are also essential.