Rotator cuff tears: pathology and repair

By virtue of its anatomy and function, the rotator cuff is vulnerable to considerable morbidity, often necessitating surgical intervention. The factors contributing to cuff disease can be divided into those extrinsic to the rotator cuff (most notably impingement) and those intrinsic to the cuff (age-related degeneration, hypovascularity and inflammation amongst others). In an era of emerging biologic interventions, our interventions are increasingly being modulated by our understanding of these core processes, many of which remain uncertain today. When we do intervene surgically, the techniques we employ are particularly challenging in the context of the tremendous pace of advancement. Several recent studies have shown that arthroscopic repair gives similar functional results to that of mini-open and open procedures, with all the benefits of minimally invasive surgery. However, the ‘best’ repair construct remains unknown, with wide variations in surgeon preference. Here we present a literature review encompassing recent developments in our understanding of basic science in rotator cuff disease as well as an up-to-date evidence-based comparison of different techniques available to the surgeon for cuff repair.     

Rotator cuff degeneration: etiology and pathogenesis

By virtue of its anatomy and function, the rotator cuff is vulnerable to considerable morbidity, often necessitating surgical intervention. How we intervene is governed by our understanding of the pathological mechanisms in cuff disease. These factors can be divided into those extrinsic to the rotator cuff (impingement, demographic factors) and those intrinsic to the cuff (age-related degeneration, hypovascularity, inflammation, and oxidative stress, among others). In an era where biologic interventions are increasingly being investigated, our understanding of these mechanisms is likely to become more important in designing effective new interventions. Here we present a literature review summarizing our current understanding of the pathophysiological mechanisms underlying rotator cuff degeneration.     

Rotator cuff sonography: a reassessment

This study is both a retrospective and prospective evaluation of the clinical usefulness of shoulder sonography. Ninety-eight patients suspected of having rotator cuff tears underwent sonography of both shoulders. Sixty-two patients underwent double-contrast arthrography performed on the same day as sonography, and 38 patients underwent surgery after sonography. A comparison of the results from ultrasound and arthrography, using published diagnostic criteria, demonstrated a sensitivity of 75% and a specificity of 43% for detection of a rotator cuff tear. In this study, use of more restricted criteria, a subset of the published criteria, yielded a sensitivity of 68% and a specificity of 90%. A comparison of sonography with surgery, using this study's criteria, demonstrated a sensitivity of 57% and a specificity of 76%. This report shows that shoulder sonography is less reliable than previously reported and appears to have a very limited role in the evaluation of rotator cuff injuries.     

Rotator cuff: biology and current arthroscopic techniques

The present article summarizes current trends in arthroscopic rotator cuff repairs focusing on the used repair technique, potential influencing factors on the results, and long-term outcome after reconstruction of the rotator cuff. Moreover, different treatment options for the treatment for irreparable rotator cuff ruptures were described, and the results of additional augmentation of the repairs with platelet-rich plasma were critically analyzed. Based on the current literature, double-row repairs did not achieve superior clinical results compared to single-row repairs neither in the clinical results nor in the re-rupture rate. Multiple factors such as age, fatty infiltration, and initial rupture size might influence the results. If the rupture is not repairable, various options were described including cuff debridement, partial repair, tuberoplasty, or tendon transfers. The additional augmentation with platelet-rich plasma did not reveal any significant differences in the healing rate compared to conventional rotator cuff repairs. LEVEL OF EVIDENCE: IV.     

Rotator cuff tears: diagnosis with sonography

The purpose of this study was to determine the accuracy of sonography in the detection of rotator cuff tears. Eighty-one patients were referred by orthopedic specialists because of a clinical suspicion of rotator cuff tear. The standards of comparison were arthrography in 79 cases and surgery in two cases. The sonographic technique used was based on a review of the literature and experience gained by scanning normal subjects. The sonographic criteria for the diagnosis of a complete rotator cuff tear were a focal defect in the cuff or complete absence or nonvisualization of the cuff. All sonograms were interpreted prospectively without knowledge of arthrographic or surgical results. With arthrography as the standard of comparison for the diagnosis of rotator cuff tear, sonographic results included 15 true-positives, 52 true-negatives, eight false-negatives, and four false-positives. With surgery as the standard of comparison, the results were one true-positive and one true-negative sonogram. The sensitivity of sonography in detecting rotator cuff tear was 0.67, the specificity was 0.93, and the accuracy was 0.85. Our study found lower sensitivity and accuracy results for shoulder sonography than have been previously reported.     

Rotator cuff lesions: evaluation with RM and US

Physical and instrumental examination of the patients with an "aching shoulder" is often difficult and a positive out-come of surgical treatment may be impaired by the late diagnosis of long-standing rotator cuff lesions causing tendon adhesions and muscle atrophy. The authors report the results obtained in 25 selected patients with an aching shoulder examined with arthrography, real-time ultrasound (US) with a 5 MHz linear probe, and high-field (1.5 T) Magnetic Resonance (MR) imaging. Arthrography was able to demonstrate a cuff tear in 14/25 cases; US detected signs of tear in 14/25 (1 false negative); MR imaging showed a cuff lesion in 16/25 patients, and in one case allowed a partial cuff tear to be demonstrated, which had not been visualized with arthrography. MR imaging could also demonstrate other signs of periarticular pathologies (tendinitis, longhead of biceps inflammation, and bursitis) that may represent the early stages of the inflammatory-degenerative process underlying most of cuff lesions. The high diagnostic accuracy of US (95%) is stressed in the detection of cuff tears, in patients with an aching shoulder; as for questionable cases at US, MR imaging is indicated as a valid alternative to arthrography, which is more invasive and less accepted by the patients.     

Rotator cuff disruption: diagnosis with digital arthrography

Shoulder arthrography is a reliable technique for use in the diagnosis of tears of the rotator cuff, although delineation of the precise site and size of tears requires meticulous double-contrast technique and considerable examiner expertise. The authors initiated a prospective evaluation of digital arthrography of the glenohumeral joint in 28 patients with clinical manifestations suggesting rotator cuff tear because they believed that examination with this technique would allow more accurate definition of the precise status of the cuff. Fifteen patients had normal studies. Ten complete and three partial rotator cuff tears were demonstrated with digital technique, and the precise site of the tear was demonstrated in all of these cases. The results indicate that digital arthrography of the glenohumeral joint may have some advantages over standard arthrography in the delineation of complete and partial tears of the rotator cuff, particularly in defining the exact site of tears.     

Rotator cuff lesions. Acute and chronic

The complex anatomy of the shoulder often impedes the orthopedic surgeon's evaluation and understanding of injuries to the shoulder joint, particularly the rotator cuff muscle-tendon complex. Arthroscopy, MRI, and digital data analysis are several techniques now at the surgeon's disposal. This article reviews the application of these techniques in the evaluation of rotator cuff injuries.     

Rotator cuff: evaluation with US and MR imaging.

Magnetic resonance (MR) and ultrasound (US) imaging are currently touted for assessment of rotator cuff disease. Optimum clinical imaging techniques include use of (a) a 1.5-T MR imaging unit with small planar coils, proton-density-weighted and T2-weighted fast spin-echo sequences, and 10-12-cm fields of view (yielding 400-470 x 500-625-microm in-plane spatial resolution) and (b) a state-of-the-art commercial US unit with insonation frequencies of 9-13 MHz (yielding 200-400-microm axial and lateral resolution). Proper diagnosis requires familiarity with normal anatomic characteristics and imaging pitfalls. Care must be taken to avoid sonographic tendon anisotropy and MR imaging magic angle effects, which can be misinterpreted as rotator cuff tear. At MR imaging, a complete cuff tear typically appears as either a hyperintense defect or a tendinous avulsion that extends from the bursal to the articular side of the cuff; a partial cuff tear typically appears as a focal hyperintense region that contacts only one surface of the cuff. Complete and partial tears manifest with a wide spectrum of findings at US. MR imaging and US are effective for evaluating rotator cuff injuries, with high reported accuracies for detection of complete tears but more disparate results for detection of partial tears.     

Rotator cuff tears: correlation of sonographic and surgical findings

High-resolution, real-time sonography of the rotator cuff was performed in 51 shoulders, and the results were correlated with findings obtained during subsequent surgery. Prospective sensitivity of sonography in detection of a tear was 100%; specificity, 75%; and accuracy, 92%. Retrospective estimation of tear size on sonograms correlated well with the intraoperative measurements for small and moderate lesions. Large lesions were often underestimated sonographically. Retrospectively, partial tears were correctly diagnosed in seven patients, and bursal thickening was recognized in 17 patients. Sonography of the shoulder proved to be an accurate, noninvasive method for the diagnosis of complete rotator cuff tears. It is useful for estimating tear size and location and may be useful in recognizing partial tears.     

Rotator cuff lesions: signal patterns at MR imaging

The signal intensity patterns of rotator cuff lesions at magnetic resonance (MR) imaging were evaluated in 80 patients who had surgical correlation and in 13 asymptomatic individuals (14 shoulders). Six cadaver shoulders were examined with MR, and histologic correlation was obtained in four. All studies were performed at 1.5 T with a flexible circular surface coil. The accuracy of MR imaging in detection of full-thickness cuff tears (31 patients) was 0.95 and of partial thickness tears (16 patients), 0.84. The most common and accurate pattern for full-thickness cuff tears (22 of 31 tears) was a region of intense signal seen on T2-weighted images. Less often the torn region consisted of an extremely degenerated and attenuated tendon with moderate signal intensity or was obscured by low-signal-intensity scar. The intense signal pattern on T2-weighted images was also accurate, although a less common finding (seven of 16 cases), in the diagnosis of partial tears. Tendinitis was recognized as focal or diffuse regions of increased signal intensity or a nonhomogeneous pattern of increased signal often associated with tendinous enlargement. In some patients, manifestations of subacromial-subdeltoid bursitis was present. Tendon degeneration was also manifested as regions of increased signal intensity. Some similarity and overlap of signal patterns of partial interstitial tears, tendinitis, and tendon degeneration are observed.     

Rotator cuff tear: clinical experience with sonographic detection

Between June 1986 and April 1988, 86 sonographic examinations of the shoulder were performed on patients suspected of having rotator cuff tears. Major sonographic diagnostic criteria included (a) a well-defined discontinuity usually visible as a hypoechoic focus within the cuff, (b) nonvisualization of the cuff and (c) an echogenic focus within the cuff. Seventy-five patients underwent both sonography and arthrography. Compared with arthrography alone, ultrasound examinations enabled detection of 92% of rotator cuff tears (24 of 26 tears), with a specificity of 84% and a negative predictive value of 95%. Correlation was obtained in 30 of these patients who underwent surgery for rotator cuff tear or other soft-tissue abnormality. In this group, the sensitivity of sonography for detection of a tear was 93%, with a specificity of 73%, while for arthrography sensitivity was 87% and specificity was 100%. These data indicate that sonography is a useful, noninvasive screening procedure for patients suspected of having rotator cuff injury.     

肩袖撕裂的肩关节MR造影评价

目的 评价肩关节MR造影对肩袖撕裂的诊断价值。方法 分析32例病人的肩关节MR造影图像,评价内容包括肩袖肌腱、盂唇、肱二头肌长头腱,结果与肩关节镜及肩部开放手术比较。结果 以肩关节镜和手术结果为标准,32例病人包括14例全层撕裂,6例下表面部分撕裂,12例无撕裂。肩关节MR造影判定有无肩袖撕裂的敏感性、特异性和准确性都为100％;诊断全层撕裂的敏感性、特异性和准确性分别为100％、94％和97％。同时,肩关节MR造影还正确诊断了所有的多肌腱撕裂、合并的盂唇异常及肱二头肌长头腱异常。结论 肩关节MR造影可以准确、全面地评价肩袖撕裂。     

Rotator cuff tears: evaluation using double-contrast shoulder arthrography

To determine the accuracy of double-contrast arthrography in complete rotator cuff tears, we studied 805 patients thought to have a complete rotator cuff tear who had undergone double-contrast shoulder arthrography (DCSA) between 1978 and 1983. The results of this study indicate that DCSA is exquisitely sensitive and as accurate as the single-contrast examination. The site of disruption was directly visualized in 93% of cases, and the size of the defect and status of the torn tendon edges were reliably predicted. Such information may influence the surgeon in patient selection for operative repair as well as surgical approach.     

Rotator cuff tears: diagnostic performance of MR imaging

To determine the diagnostic performance of magnetic resonance (MR) imaging in the evaluation of suspected rotator cuff tears, eight asymptomatic volunteers and 32 patients with rotator cuff tendonopathy who underwent surgery were examined with MR imaging. Twenty-four of these patients also underwent contrast arthrography. The ability of MR imaging to depict the size of cuff tears and the quality of torn tendon edges was also evaluated. The MR imaging and arthrographic studies were reviewed without knowledge of surgical results or of the other studies. A scoring system was developed and a score assigned to each patient's MR study. The sensitivity of MR imaging for all tears (partial and full thickness) was 0.91, and the specificity was 0.88; whereas the sensitivity and specificity of arthrography were each 0.71. The scoring system improved the sensitivity to 1.0 and the specificity to 0.92. Linear regression analysis showed excellent correlation between preoperative assessment of the size of rotator cuff tears and measurement at surgery (r = .95).     

Rotator cuff tears: association with acromion angulation on MRI

ObjectiveUsing magnetic resonance imaging (MRI), evaluate the correlation of acromion angulation with thickening of the coracoacromial ligament (CAL) and narrowing of the subacromial space resulting in impingement upon the rotator cuff tendons.Materials and methodsEighty-nine shoulder MRI studies performed on a 3T scanner were retrospectively analyzed by two blinded independent reviewers. Measurements of the acromion angle (delta angle), CAL thickness and distance between the CAL and humeral head were obtained. The data were categorized into two groups, delta angle less that and greater than 7.5°. The presence or absence of full thickness (FT) or near full thickness (NFT) rotator cuff tears was noted.ResultsIn group 1, the acromion angle varied from -6.8 to 6.8° (1.7±3.5°) with a CAL thickness of 0.91±0.20 mm and a subacromial distance of 6.47±0.88 mm. Group 2 acromion angle varied from 7.6° to 46.8° (18.0°±8.1°) with a CAL of 1.77±0.51 mm and a subacromial distance of 4.52±0.82 mm. The difference in CAL thickness and subacromial distance were significantly different between the two groups (P<.001). In Group 1, 3 out of 51 patients had a FT or NFT tear of the rotator cuff compared to 20 out of 38 in Group 2 (P<.001). There was no significant interobserver variability.ConclusionSteep acromion angulation is associated with CAL thickening and narrowing of the subacromial space. Patients with a steep acromion angle had a statistically increased incidence of rotator cuff tears.