Histological, radiological and clinical analysis of the supraspinatus tendon and muscle in rotator cuff tears

Abstract

Background Macroscopic alterations of the affected rotator cuff (RC) are undoubtedly linked to microscopic changes, but they may underestimate the actual degree of the disease. Moreover, it remains unclear whether preoperative structural RC changes may alter clinical outcomes. Methods Supraspinatus tendon and muscle samples were collected from 47 patients undergoing RC surgery. Tendons were evaluated histologically according to the Bonar score; fatty infiltration and muscle atrophy were quantified using a software for biomedical image analysis (ImageJ) in percentage of area affected in the observed muscle section. Preoperative shoulder ROM and pain were evaluated. Radiological muscle atrophy was evaluated with the Tangent Sign and Occupation Ratio; fatty infiltration was assessed according to the Goutallier classification. Correlations between histological, radiological and clinical outcomes were assessed. Statistics were performed using the Spearman correlation coefficient. Intraobserver and interobserver agreement was calculated. Results Histopathologic fatty infiltration (r = 0.007, p = 0.962), muscle atrophy (r = 0.003, p = 0.984) and the total Bonar score (r = 0.157, p = 0.292) were not correlated to preoperative shoulder pain. Muscle atrophy showed a significant but weak negative correlation with the preoperative movement of abduction (r = -0.344, p = 0.018). A significant but weak positive correlation was found between muscle atrophy and the total Bonar score (r = 0.352, p = 0.015). No correlation between histological and radiological evaluation was found for both fatty infiltration (r = 0.099, p = 0.510) and muscle atrophy (Tangent Sign: r = -0.223, p = 0.131; Occupation Ratio: r = -0.148, p = 0.319). Our histological evaluation showed a modal value of 3 (out of 3) for fatty infiltration and an equal modal value of 2 and 3 (out of 3) for muscle atrophy. In contrast, the modal value of the Goutallier score was 1 (out of 4) and 28 patients out of 47 showed a negative Tangent sign. At histology, intraobserver agreement ranged from 0.59 to 0.81 and interobserver agreement from 0.57 to 0.64. On the MRI intraobserver agreement ranged from 0.57 to 0.71 and interobserver agreement ranged from 0.53 to 0.65. Conclusions Microscopic muscle atrophy appeared to negatively correlate with the movement of abduction leading to functional impairment. Shoulder pain did not show any relationship with microscopic changes. Radiological evaluation of the supraspinatus muscle alterations seemed to underestimate the degree of the same abnormalities evaluated at histology.

Validation of computer-based analysis of static ultrasound images of patellar and Achilles tendon enthesis territories

“…The use of computer analysis of static images lacks precedent in the examination of load-bearing tendons, let alone in the investigation of entheseal territories. Existing experience in muscle tissue [12] and rotator cuff tendons [13] is scarce, albeit positively indicative of validity.…”

“…Computer analysis presents three notable limitations: firstly, the time required for completion and the need to process images outside the equipment generating them may limit its utility to research purposes or occasional auxiliary monitoring [12,13]. Secondly, acoustic shadows caused by hyperechoic bodies, such as calcifications or enthesophytes [15,16], may be interpreted as anechoic zones, affecting the average grayscale intensity parameters and their dispersion.…”

Facile and rapid fabrication of a novel 3D-printable, visible light-crosslinkable and bioactive polythiourethane for large-to-massive rotator cuff tendon repair

“…This study showed that a majority (35%) of injuries occurred in the tendon midsubstance [ 4 ]. If left unaddressed, such tendon ruptures can pathologically progress into chronic multi-tissue injuries that include bone loss and skeletal muscle fatty degeneration [ [1] , [2] , [3] , 5 , 6 ]. Although rotator cuff surgeries have been estimated to save the United States economy approximately US$ 3.44 billion annually [ 7 ], bibliometric analyses [ 8 , 9 ] indicate that advances in biomaterial scaffolds are still being actively pursued, with existing tendon scaffolds possessing their own inherent advantages and disadvantages [ 10 ].…”

“…Indeed, mechanical attributes such as subpar tendon stiffness have been shown to negatively impact the efficiency of musculoskeletal movement [ 13 ] while inadequate tensile strength [ 14 ] or poor suture retention [ 15 ] may predispose a tendon to failure even after surgical repair. From a biological perspective, tendons often do not fully regenerate and instead heal by fibrovascular scar tissue formation [ 6 , 16 ]. Given that tendon tissue structure, such as collagen fiber crimping, is important for tendon's mechanical response [ 17 ], the loss of highly aligned, load-bearing collagen fibers results in mechanically weakened tissue, reducing tendon's tensile strength by as much as 70% [ 18 ].…”

Conservative Management of Partial Thickness Rotator Cuff Tears: A Systematic Review

“…23 The prevalence and impact of these tears underscore the significance of effective management strategies to optimize patient outcomes and prevent potential disease progression. 24 Given the significant burden in terms of disability and pain, particularly in young overhead athletes (reported incidence up to 40%), it is crucial to determine a universal diagnostic and treatment algorithm to manage PT-RCTs in the most effective way. 10,25 Currently, there is no universally accepted algorithmic treatment strategy for patients with symptomatic PT-RCTs.…”