Conventional MR in rotator cuff pathology. Is it sufficient?

Background

Magnetic resonance (MR) provides detailed information for the depiction of shoulder lesions. It allows a unique anatomical and tissue characterization providing a detailed evaluation of the rotator cuff (RC) and the surrounding bones.

Are pain location and physical examinations useful in locating a tear site of the rotator cuff?

BACKGROUND: Pain is the most common symptom of patients with rotator cuff tendinopathy, but little is known about the relationship between the site of pain and the site of cuff pathologic lesions. Also, accuracies of physical examinations used to locate a tear by assessing the muscle strength seem to be affected by the threshold for muscle weakness, but no studies have been reported regarding the efficacies of physical examinations in reference to their threshold. HYPOTHESIS: Pain location is useful in locating a tear site. Efficacies of physical examinations to evaluate the function of the cuff muscles depend on the threshold for muscle weakness. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The authors retrospectively reviewed the clinical charts of 160 shoulders of 149 patients (mean age, 53 years) with either rotator cuff tears (140 shoulders) or cuff tendinitis (20 shoulders). The location of pain was recorded on a standardized form with 6 different areas. The diagnostic accuracies of the following tests were assessed with various thresholds for muscle weakness: supraspinatus test, the external rotation strength test, and the lift-off test. RESULTS: Lateral and anterior portions of the shoulder were the most common sites of pain regardless of existence of tear or tear location. The supraspinatus test was most accurate when it was assessed to have positive results with the muscle strength less than manual muscle testing grade 5, whereas the lift-off test was most accurate with a threshold less than grade 3. The external rotation strength test was most accurate with a threshold of less than grade 4+. CONCLUSION: The authors conclude that pain location is not useful in locating the site of a tear, whereas the physical examinations aiming to locate the tear site are clinically useful when assessed to have positive results with appropriate threshold for muscle weakness.     

Muscle atrophy as a consequence of rotator cuff tears: should we compare the muscles of the rotator cuff with those of the deltoid?

Purpose The quantitative assessment of muscle atrophy has a degree of importance in prognosticating rotator cuff treatment. However, it has been conjectured that muscle fat increases with aging. Therefore, we thought that the quantitative assessment of the supraspinatous would be better if made in comparison with a standard of reference such as the deltoid. Consequently, we performed a two-part study, first evaluating supraspinatous changes compared with the deltoid in “normals” with aging, and second, determining if in patients with cuff tears the supraspinatous fat exceeds that of the deltoid. Materials and methods In part 1, we studied 50 patients stratified by decade. In the first sitting, two blinded independent observers quantitatively graded the deltoid (with the supraspinatous obscured) and in the second sitting the same two observers quantitatively graded the supraspinatous (with the deltoid obscured). In part 2 of the study, we evaluated patients with moderate rotator cuff tears (>2 cm) and performed the same blinded, two-sitting, quantitative assessment (with the comparison muscle obscured). Results We found that muscle atrophy increases with age in patients without tears (0.011/0.028 U/year), although to a greater degree in the deltoid (p = 0.032). Also, in similarly aged patients, quantitative scores of the deltoid closely matched those of the supraspinatous (p = 0.071). Notably, however, in patients with large tears, the supraspinatous showed significant changes disproportionate to those of the deltoid, regardless of patient age (p = 0.044). Conclusion In the presence of a normal rotator cuff, fatty infiltration increases with age. Age-related changes occur more frequently in the deltoid, verifying this muscle’s potential as a standard of reference. With cuff tears, supraspinatous atrophy was disproportionate to that of the deltoid. Therefore, systematic assessment of supraspinatous muscle atrophy may be more reliable using the deltoid as a control for comparison than assessing it in isolation.     

Tenocyte apoptosis in the torn rotator cuff: a primary or secondary pathological event?

Little information exists on the contribution of apoptosis to pathological tendon changes in rotator cuff tendinopathy. The purpose of this study was to quantitate the rate of tenocyte apoptosis in torn supraspinatus tendons and in the matched intact subscapularis and to examine the potential relation between apoptotic index (AI) and tendon pathology. In addition, the authors examined tenocyte density, proliferation rate and p53 gene expression patterns to gain further insight into relevant pathological mechanisms in the torn suprapinatus. 15 torn supraspinatus tendons with matched intact subscapularis tendon samples and 10 reference subscapularis samples were collected. Immunohistochemistry was used to define the AI (F7-26), proliferation rate (Ki67) and presence of p53 (M7001). Tendon degeneration was evaluated according to the Bonar scale. Expression of p53 and relevant genes (n=84) was examined on a subset of samples using microfluidic arrays. The AI was significantly increased in torn supraspinatus tendon and matched subscapularis tendon (R2 =0.5742; p=0.0005). Cell density and proliferation rate were also elevated in torn supraspinatus compared with reference subscapularis tendons (p<0.05). A significant increase in p53 occurred specifically in torn supraspinatus tendon (p<0.05), and several genes encoding p53-inhibiting proteins were downregulated in association, including HDAC1 (p<0.05), MDM4 (p<0.001) and PPM1D (p<0.05). Our results suggest that tenocyte apoptosis results from more than one mechanism in the injured rotator cuff, including both intrinsic factors related specifically to the torn supraspinatus tendon, as well as a more generalised effect on the adjacent subscapularis tendon.     

Tendon–bone contact pressure and biomechanical evaluation of a modified suture-bridge technique for rotator cuff repair

The aim of the study was to evaluate the time-zero mechanical and footprint properties of a suture-bridge technique for rotator cuff repair in an animal model. Thirty fresh-frozen sheep shoulders were randomly assigned among three investigation groups: (1) cyclic loading, (2) load-to-failure testing, and (3) tendon–bone interface contact pressure measurement. Shoulders were cyclically loaded from 10 to 180 N and displacement to gap formation of 5- and 10-mm at the repair site. Cycles to failure were determined. Additionally, the ultimate tensile strength and stiffness were verified along with the mode of failure. The average contact pressure and pressure pattern were investigated using a pressure-sensitive film system. All of the specimens resisted against 3,000 cycles and none of them reached a gap formation of 10 mm. The number of cycles to 5-mm gap formation was 2,884.5 ± 96.8 cycles. The ultimate tensile strength was 565.8 ± 17.8 N and stiffness was 173.7 ± 9.9 N/mm. The entire specimen presented a unique mode of failure as it is well known in using high strength sutures by pulling them through the tendon. We observed a mean contact pressure of 1.19 ± 0.03 MPa, applied on the footprint area. The fundamental results of our study support the use of a suture-bridge technique for optimising the conditions of the healing biology of a reconstructed rotator cuff tendon. Nevertheless, an individual estimation has to be done if using the suture-bridge technique clinically. Further investigation is necessary to evaluate the cell biological healing process in order to achieve further sufficient advancements in rotator cuff repair.     

Is coracoacromial arch angle a predisposing factor for rotator cuff tears?

PURPOSE

The aim of the present study was to investigate whether coracoacromial arch angle is a predisposing factor for rotator cuff tears.

METHODS

Shoulder magnetic resonance imaging (MRI) examinations of 40 patients having shoulder arthroscopy due to rotator cuff tears and 28 patients with normal MRI findings were evaluated retrospectively. Acromio-humeral distance, coraco-humeral distance, the angle between the longitudinal axis of the coracoacromial ligament and longitudinal axis of the acromion (coracoacromial arch angle), and thickness of the coracoacromial ligament were measured.

RESULTS

In patients with rotator cuff pathology the mean coraco-humeral distance was 7.88±2.37 mm, the mean acromio-humeral distance was 7.89±2.09 mm, and the mean coracoacromial arch angle was 132.38°±6.52° compared to 11.67±1.86 mm, 11.15±1.84 mm, and 116.95°±7.66° in the control group, respectively (P < 0.001, for all). In regression analysis, all three parameters were found to be significant predictors of rotator cuff tears. The mean thickness of the coracoacromial ligament was not significantly different between the patient and control groups (0.95±0.30 mm vs. 1.00±0.33 mm, P > 0.05).

CONCLUSION

Acromio-humeral and coraco-humeral distances are narrower than normal limits in patients with rotator cuff tears. In addition, coracoacromial arch angle may be a predisposing factor for rotator cuff tears.The most common cause of shoulder pain is rotator cuff pathology, especially in advanced age. Repetitive overhead arm activities, advanced age, morphology of the glenohumeral joint, acromion type, and soft tissue pathologies surrounding the joint have been introduced among its etiologies (1, 2). Neer and et al. (3) defined impingement as a cause of rotator cuff tear in 1972. They also showed that other than shape of the acromion, the coracoacromial ligament and acromioclavicular ligament were associated with tears (3). In later studies it was determined that shoulders with rotator cuff tear had smaller supraspinatus outlet area (4). Burns and Whipple (5) found that the coracoacromial ligament was more effective on impingement than acromion type. Therefore, coracoacromial arch geometry has gained importance and numerous studies, mostly on cadavers, have been performed.The aim of the present study was to investigate whether the coracoacromial arch angle is a predisposing factor for rotator cuff injury.     

Comparison of arthroscopic rotator cuff repair in healthy patients over and under 65 years of age

We compared the outcomes of arthroscopically repaired rotator cuff tears in 28 patients older than 65 years (the over 65 group: median age 70 years) with a control group of 28 patients younger than 65 years (the under 65 group: median age 57 years). The groups were similar in regard to sex distribution, surgical technique, and post-operative rehabilitation programmes, but different in age. After careful arthroscopic evaluation of the full-thickness rotator cuff tear, rotator cuff repair and biceps tenotomy were performed in all patients. Pre- and post-operatively, each patient was evaluated for range of motion, shoulder score (UCLA), and SF-36 self-administered questionnaire. Comparing pre- versus post-operative status at a minimum 24 months follow-up, forward elevation, internal and external rotation, modified UCLA rating system scores, and SF-36 scores improved significantly in both groups, with no significant difference between the groups. At the last follow-up, strength improved significantly in both groups, with non-significant intergroup difference. The Popeye sign was detected in 13/28 (46%) of the patients in the over 65 group and in 11/28 (39%) in the under 65 group (χ = 0.29) with non-significant difference between the two groups. In selected active patients older than 65, arthroscopic rotator cuff repair associated with biceps tenotomy (when necessary) can yield clinical and related quality of life outcomes similar to those of patients younger than 65 years.