Background: Musculotendinous retraction is a limiting factor for repair of long-standing rotator cuff tears. However, it is currently unknown to what extent the muscle and tendon contribute to the degree of total retraction. Further understanding of this may possibly influence the strategy of musculotendinous reconstruction.
Purpose: To analyze the contribution of muscle and tendon to the process of myotendinous retraction.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: Magnetic resonance imaging of 130 shoulders with intact (n = 20) or completely torn supraspinatus tendons was analyzed. Fatty infiltration of the supraspinatus muscle was graded according to Goutallier stages. The degree of retraction of the tendon stump and of the musculotendinous junction was assessed.
Results: There were 30 shoulders without evidence of supraspinatus fatty infiltration, 25 with stage 1, 23 with stage 2, 25 with stage 3, and 15 with stage 4 changes. The corresponding tear sizes (distance of tendon end from greater tuberosity) were 4, 21, 27, 37, and 41 mm; the distance of the myotendinous junction from the greater tuberosity was 22, 33, 39, 48, and 48 mm; and the length of the tendons (distance of tendon end to myotendinous junction) was 19, 13, 12, 11, and 8 mm, respectively. In Goutallier stage 3 and above, and in case of a positive tangent sign, the musculotendinous junction was, in 90% of the cases, retracted to or beyond the glenoid.
Conclusion: Musculotendinous retraction in chronic rotator cuff tears results mainly from shortening of the muscle fibers but in advanced stages results also from shortening of the tendon tissue itself. The present data demonstrate, for the first time, that the residual tendon stump in a tendon tear does not have the length of the original tendon and is further shortened over time. Therefore, direct anatomic tendon reinsertion will result in lengthening of the supraspinatus muscle greater than what it would have been before the tear.
Background: The alterations in blood flow after rotator cuff repair remain unclear. Visualization of vascular patterns could clarify basic and clinical investigations.
Purpose: To assess longitudinal blood flow inside the repaired cuff and the surrounding tissue after rotator cuff repair, using contrast-enhanced ultrasonography.
Study Design: Descriptive laboratory study.
Methods: Fifteen patients (7 men and 8 women; mean age, 65.0 ± 9.8 years) consented to participate. The patients underwent an ultrasound scan before and 1, 2, and 3 months after surgery. Enhanced ultrasound images were recorded for 1 minute after intravenous injection of contrast reagent. Four regions of interest inside the cuff and 2 regions in the anchor hole and subacromial bursa were superimposed on the obtained images. Calculated areas under the time-intensity curves were expressed in acoustic units (AU).
Results: We found area-dependent differences in patterns of alteration and magnitude of blood flow inside the repaired cuff and peritendinous tissues. Vascularity in the articular distal and bursal distal region of the repaired cuff at 1 month postoperatively increased significantly compared with that at the preoperative baseline (76 vs 5 AU, P = .0037; 92 vs 7 AU, P = .043). The vascularity peaked at 1 month after surgery in the bursal area within the cuff but at 2 months in the articular area. The vascularity in the articular proximal region of the repaired cuff was significantly lower than that in the bursal proximal (P = .0046), bursal distal (P = .0183), and articular distal regions (P = .0163) 1 month after surgery.
Conclusion: Enhancement patterns in intratendinous tissue increased at 1 or 2 months postoperatively and decreased at 3 months. We found area-dependent differences in enhancement patterns inside the repaired cuff and peritendinous tissue.
Clinical Relevance: Visualization of vascularization using contrast-enhanced ultrasound could help in deciding on an appropriate repair technique or on the form of postoperative rehabilitation after rotator cuff repair.
Background: Hypoxia and decreased blood supply have been proposed as risks for tendon rupture. Visualization of the vascularity of intact and torn rotator cuffs would be useful for improving treatments for rotator cuff tear.
Purpose: To assess vascularity inside a tendon or an adjacent rotator cuff insertion point in patients differing in age and extent of damage to the tendon.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: Ten volunteers (all men) and 15 patients (10 men, 5 women) consented to participate in the study. Contrast agent for enhanced ultrasound was injected intravenously. Enhanced ultrasound images of the torn cuff and the contralateral shoulder were recorded for 1 minute. Four small regions of interest, the articular and bursal sides of the tendon and the medial and lateral sides of the bursa, were studied in all shoulders.
Results: There was a significant decrease in blood flow in the intratendinous region in elderly subjects compared with young subjects, but age had no effect on blood flow in bursal tissue. Blood flow in ruptured rotator cuffs did not differ from that in intact rotator cuffs. The intraclass correlation coefficient for intraobserver reproducibility was 0.82 (95% confidence interval: 0.77-0.86).
Conclusions: The findings of this investigation were the hypovascular pattern in intratendinous tissue compared with the subacromial bursa, the age-related decrease in intratendinous vascularity, and the hypovascular pattern in the tendon, regardless of rupture of the tendon. Clarification of vascular patterns inside or around the torn ends of a rotator cuff will assist in the development of successful treatments for torn rotator cuffs.
Background: Although magnetic resonance imaging (MRI) is a standard method of assessing the extent and features of rotator cuff disease, the authors are not aware of any studies that have assessed the interobserver agreement among orthopaedic surgeons reviewing MRI scans for rotator cuff disease.
Hypothesis: Fellowship-trained orthopaedic shoulder surgeons will have good interobserver agreement in predicting the more salient features of rotator cuff disease such as tear type (full thickness versus partial thickness), tear size, and number of tendons involved but only fair agreement with more complex features such as muscle volume, fat content, and the grade of partial-thickness cuff tears.
Study Design: Cohort study (diagnosis); Level of evidence, 3.
Methods: Ten fellowship-trained orthopaedic surgery shoulder specialists reviewed 27 MRI scans of 27 shoulders from patients with surgically confirmed rotator cuff disease. The ability to interpret full-thickness versus partial-thickness tears, acromion type, acromioclavicular joint spurs or signal changes, biceps lesions, size and grade of partial-thickness tears, acromiohumeral distance, number of tendons involved and amount of retraction for full-thickness tears, size of full-thickness tears, and individual muscle fatty infiltration and atrophy were assessed. Surgeons completed a standard evaluation form for each MRI scan. Interobserver agreement was determined and a kappa level was derived.
Results: Interobserver agreement was highest (>80%) for predicting full- versus partial-thickness tears of the rotator cuff, and for quantity of the teres minor tendon. Agreement was slightly less (>70%) for detecting signal in the acromioclavicular joint, the side of the partial-thickness tear, the number of tendons involved in a full-thickness tear, and the quantity of the subscapularis and infraspinatus muscle bellies. Agreement was less yet (60%) for detecting the presence of spurs at the acromioclavicular joint, a tear of the long head of the biceps tendon, amount of retraction of a full-thickness tear, and the quantity of the supraspinatus. The best kappa statistics were found for detecting the difference between a full- and partial-thickness rotator cuff tear (0.77), and for the number of tendons involved for full-thickness tears (0.55). Kappa for predicting the involved side of a partial-thickness tear was 0.44; for predicting the grade of a partial-thickness tear, it was –0.11.
Conclusions: Fellowship-trained, experienced orthopaedic surgeons had good agreement for predicting full-thickness rotator cuff tears and the number of tendons involved and moderate agreement in predicting the involved side of a partial-thickness rotator cuff tear, but poor agreement in predicting the grade of a partial-thickness tear.
Background: Biplane radiologic evaluation is indispensable for the correct diagnosis of acute acromioclavicular (AC) joint injuries. Thus far, no functional radiographic techniques have been quantified to evaluate horizontal instability in acute AC joint dislocations.
Hypothesis: Supine dynamic axillary lateral shoulder views detect horizontal instability of the distal clavicle in patients with acute AC joint dislocations.
Study Design: Cohort study (Diagnosis); Level of evidence, 2.
Methods: Twenty-five consecutive patients with a mean age of 39 ± 14 years with acute AC joint injury underwent biplane radiologic evaluation, including a conventional Zanca view and an axillary lateral view in a sitting position. In addition, supine axillary lateral views with the arm in 90° of abduction and 60° of flexion and extension were taken to evaluate the horizontal dynamics of the distal clavicle. The gleno-acromio-clavicular angle (GACA) was introduced and used to quantify the horizontal clavicular dynamics in terms of angle differences. The unaffected shoulders served as the control group.
Results: Superior dislocation of the lateral clavicle in the Zanca view was classified as Rockwood type II in 7 patients, type III in 15, and type V in 3. The axillary lateral view in a sitting position showed posterior dislocation of the distal clavicle in 8 patients (Rockwood type IV injury). Dynamic radiologic evaluation revealed an average GACA difference between the neutral and anterior position of the arm of 7.1° ± 5.5° for the unaffected shoulder. In the injured AC joints, 11 patients showed no radiologic evidence of horizontal instability (group A) with a GACA difference of 7.1° ± 4.8°. Increased anteroposterior translation was evident in 14 patients (group B) with a GACA difference of 30.3° ± 14.3° (P < .001).
Conclusion: Functional axillary radiologic evaluation seems to represent a simple imaging tool to reveal dynamic horizontal instability.
Clinical Relevance: Horizontal instability of the distal clavicle in acute AC joint injuries represents an indication for surgical treatment. Dynamic axillary radiologic evaluation may detect previously missed unstable injuries. This evaluation might be relevant when deciding on surgical AC joint stabilization.
