Presence Of Rotator Cuff Tear Research Articles

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.

Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear.

The anterior tilt of the acromion: radiographic evaluation and correlation with shoulder diseases.

The aim of this study was to test whether the anterior tilt of the acromion can be objectively evaluated on lateral radiographs, and whether there is a relation between this anatomical feature and the most common shoulder diseases. Lateral radiographs of 15 dried scapulas were performed in neutral position and with 5 degrees of caudal, cranial, anterior and posterior angulations. Two hundred and forty-three shoulders, both asymptomatic and affected by chronic and post-traumatic impingement, calcific tendinitis and instability, were examined by conventional radiography. The presence of rotator-cuff tears was investigated by sonography. A method was elaborated to obtain reproducible lateral radiographs and to determine the acromial tilt angle. Inter- and intraobserver and inter- and intraoperator variations in measurements were evaluated. Variations in tube angulation produced changes in tilt-angle values on dried scapulas. The average tilt angle for the chronic impingement and the instability groups were significantly different from the post-traumatic, calcific tendinitis and control groups. Rotator-cuff tears were significantly more frequent in the chronic impingement group and related to a more acute tilt angle. The inter- and intraobserver variability coefficients were 0.95 and 0.98, whereas the inter- and intraoperator variability coefficients were 0.94 and 0.96, respectively. Conventional radiography using fluoroscopy for positioning is a well-reproducible method for the evaluation of acromial tilt. There is a significant difference in tilt-angle values between some groups of subjects examined, but the lack of specificity limits the clinical importance of such measurement.

The influence of acromioclavicular joint morphology on rotator cuff tears

A detailed anatomic study of 123 shoulders was performed to define the location of the acromioclavicular (AC) joint within the supraspinatus outlet and to determine the correlation of AC joint morphologic characteristics with the presence of full-thickness rotator cuff tears (RCTs). The presence, location, and extent of RCTs were first documented for each shoulder, and 2 anatomic landmarks consisting of the anterolateral acromial corner and the inferior midpoint of the AC joint were identified and their positions digitized in 3 dimensions to calculate outlet space and clearance and AC joint locations. High resolution x-ray films were then obtained to determine the extent of degenerative changes including the location and size of inferior osteophytes and joint space. These specimens were cleaned of all soft tissues, and additional measurements were made. All data were entered into a computerized database and analyzed with respect to age, sex, and the presence of RCT. Comparison of age-matched RCT versus non-RCT groups revealed no significant differences in the position of the AC joint within the supraspinatus outlet. When AC joint morphologic characteristics were compared with those of a nontear, age-matched group, no significant differences with regard to joint space narrowing were found, but significantly larger and greater number of osteophytes were identified on both sides of the joint in the RCT group. In conclusion, the position of the AC joint is fairly constant within the supraspinatus outlet and does not appear to predispose to RCTs. The morphology of the AC joint contribution of the tears seems to be acquired in nature rather than inherent in its location within the outlet.

Release and reattachment of the coracoacromial ligament: A cadaveric study

The purpose of this study was to examine the anatomy and ability to reattach the coracoacromial ligament (CAL) after acromioplasty. Twenty-eight fresh cadaveric shoulder specimens were dissected, and the CAL dimensions and pattern of attachment were examined. The ability to reattach the CAL to the anterior acromion after acromioplasty was investigated, comparing release along the anterior acromion (traditional anterior acromioplasty) versus subperiosteal elevation from the acromial undersurface. The influence of CAL length, acromial “type”, and amount of acromioplasty on reattachment were examined. In 96% of the specimens (27 of 28) confluent medial and lateral bands of the CAL insertion along the acromion precluded “selective” release. The ability to anatomically reattach the CAL was directly related to the method of ligament release (anterior release versus subperiosteal elevation) (p < 0.0001). When directly released from along the anterior acromion, the CAL could not be anatomically reattached in any specimen. Nonanatomic reattachment to a more medial anterior acromial insertion site, however, was possible in 22 (79%) of 28 specimens. Reattachment required an average medial positioning of 60% (range 16% to 88%) along the anterior acromion from the anterolateral tip. Six (21%) specimens could not be reattached despite attempted medial positioning. In contrast, when subperiosteally elevated from the anterior inferior acromion, the CAL was reattachable in all specimens, anatomically in 26 (93%) of 28. The two nonanatomic reattachments required medially reattaching the ligament's normal acromial insertion by an average of 30%. There was no relationship between specimen sex, age, presence of rotator cuff tear, type of acromion, and CAL reattachment. The confluent anatomy of the CAL does not permit “selective” release of discretely identifiable portions of the CAL (i.e., the lateral band). In cases in which CAL restoration is important, careful subperiosteal elevation from the acromial undersurface will facilitate anatomic reattachment. Standard release of the CAL from the anterior acromion precludes anatomic, and in some cases any, reattachment of the CAL.

Magnetic resonance imaging of theshoulder: Rotator cuff disease and glenohumeral instability

Magnetic resonance imaging (MRI) has emerged as a powerful tool for the noninvasive evaluation of the musculoskeletal system. The use of MRI for the evaluation of disorders of the shoulder, however, remains more controversial than its use for the study of the knee. MRI has been shown by numerous investigators to be an accurate technique for confirming the presence of rotator cuff tears, determining their size, determining the presence of atrophy of the cuff muscles, and detecting the presence of different causes of cuff impingement. The use of MRI for the evaluation of glenohumeral instability is more problematic. In the presence of a large amount of joint fluid, MRI is reasonably accurate for the depiction of anatomic abnormalities associated with instability. In the absence of effusion, MRI is relatively inaccurate. For these cases MR arthrography is probably necessary to confirm the diagnosis.

The influence of coracoacromial arch anatomy on rotator cuff tears

We performed an anatomic study of 140 cadaver shoulders to correlate the influence of the coracoacromial arch anatomy on full-thickness rotator cuff tears (RCTs). The presence, location, and size of RCTs were initially documented. After dissection was complete 14 dimensional parameters, including humeral head size, glenoid size, and location of bony landmarks, were obtained by direct measurement. These data were entered into a computerized data base and 24 additional parameters (lengths, angles, areas) were calculated. The data were then subjected to analysis of variance and paired and unpaired t tests to determine correlation between the multiple parameters, age, sex, and left-to-right variance with RCTs. Three-dimensional computer modeling was then used to investigate the role of humeral head position in defining the available space within the coracoacromial arch (supraspinatus outlet). Overall 20% of the cadaver group exhibited full-thickness RCTs. The age group 60 years and older had a 29% incidence of RCTs compared with 5% in the group less than 60 years of age. The RCT group had a significantly greater anterior projection of the acromion than had the intact group (difference = 3.8 mm, p < 0.007). Acromial tilt was 28.5° in the RCT group and 33.5° in the intact group (p < 0.007). The supraspinatus outlet area was calculated by determining the total coracoacromial arch area and subtracting the area of the humeral head within the coracoacromial arch. The supraspinatus outlet was 22.5% smaller in the RCT group (p < 0.07). By using a series of measured and calculated parameters, we were able to characterize the anatomy of the coracoacromial arch and its relationship with the humeral head and to correlate variations in structure with the presence of RCTs. These findings may aid in our understanding of outlet impingement as a factor in the cause of RCTs.