Effect of tear size, corticosteroids and subacromial decompression surgery on the hierarchical structural properties of torn supraspinatus tendons

Association of Severe Histological Degeneration of the Torn Supraspinatus Tendon and Retear After Arthroscopic Repair of Full-Thickness Rotator Cuff Tears Using the Suture Bridge Technique

BACKGROUND

Previous studies have demonstrated several prognostic factors for retear after arthroscopic rotator cuff repair (ARCR). However, studies that histologically evaluate the quality of the torn rotator cuff (RC) tendon and its association with postoperative outcomes are limited.

PURPOSE

To investigate factors associated with retear after ARCR using the suture bridge (SB) technique, including the degree of histological degeneration of the RC tendon edge.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

The authors retrospectively evaluated 187 patients who underwent ARCR for full-thickness tears using the SB technique; intraoperative biopsy samples were taken to assess the degree of histological degeneration using the Bonar score. The cohort was divided into healed (n = 165) and retear (n = 22) groups according to magnetic resonance imaging results obtained ≥6 months postoperatively. The evaluation included preoperative patient data (age, sex, symptom duration, trauma history, history of heavy manual work, smoking habit, hypertension, diabetes mellitus, and hyperlipidemia) and radiological data (Hamada classification, Patte classification, Goutallier classification, and global fatty degeneration index [GFDI]). Additionally, intraoperative data (anteroposterior tear size, Lafosse classification for concomitant subscapularis tendon tear, and long head of biceps injury) and preoperative and postoperative clinical findings (active range of motion, University of California, Los Angeles [UCLA], score) were evaluated.

RESULTS

The retear rate was 11.8%. The retear group had a higher percentage of men (P = .031), higher Bonar score (P < .001), higher mean GFDI value (P = .002), higher rate of tear retraction degree (P = .010), and larger anteroposterior tear size (P = .020) than the healed group. The retear group had lower postoperative internal rotation (P = .031) and lower UCLA score (P < .001). Multivariate logistic regression analysis with a stepwise variable selection revealed anteroposterior tear size (odds ratio [OR], 2.4; 95% CI, 1.3-4.5; P = .004) and Bonar score (OR, 1.7; 95% CI, 1.3-2.4; P < .001) as independent predictors for a retear.

CONCLUSION

The results indicate that end-stage severe tendon degeneration might affect retear. Therefore, further investigation on the progression mechanisms of tendon degeneration and development of methods to assess degenerative tissue might improve clinical outcomes after ARCR.

Adverse Impact of Corticosteroids on Rotator Cuff Tendon Health and Repair: A Systematic Review of Basic Science Studies

Purpose

To evaluate the in vitro effects of corticosteroid injections (CSIs) on rotator cuff tendon (RCT).

Methods

A systematic review of the MEDLINE database was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for all studies reporting on adverse biochemical and biomechanical effects of CSIs on RCT.

Results

Sixteen studies were identified that had been published in the last 15 years on the effects of corticosteroids on RCTs. Eight of these studies were on human RCTs, 6 were on rat tendons, 1 considered both human and rat tendons, and 1 was on dog tendon. Five studies analyzed the effects of corticosteroids on the biomechanical properties of RCT or rotator cuff repair, whereas the remaining observed the cellular and molecular effects of CSIs on RCT. Corticosteroids suppress an inflammatory response, induce apoptosis, and have negative effects on collagen and tendon cell viability in RCTs. The mechanical properties, including load to failure of RCTs and rotator cuff repair anchor pull-out strength, also are decreased by CSIs. These in vitro effects appear to be transient as well as frequency and dose dependent.

Conclusions

On a molecular level, CSIs decrease cellular proliferation, alter collagen and extracellular matrix composition, impede inflammatory pathways, decrease cellular viability, increase adipocyte differentiation, and increase apoptosis. These changes can be seen as early as 24 hours after corticosteroid exposure, last as long as 2 to 3 weeks, and are exacerbated by increased doses and decreased latency between doses. Biomechanical studies demonstrate that these changes result in decreased maximal load to failure, tendon stiffness, and suture anchor pull-out strength in rat shoulders up to 2 weeks but not at 3 and 4 weeks, post-CSI.

Clinical Relevance

Shoulder subacromial steroid injection is common, and practitioners should be aware of results both positive and deleterious.

Degree of tendon degeneration and stage of rotator cuff disease

PURPOSE

While tendon degeneration has been known to be an important cause of rotator cuff disease, few studies have objectively proven the association of tendon degeneration and rotator cuff disease. The purpose of this study was to investigate changes of tendon degeneration with respect to the stage of rotator cuff disease.

METHODS

A total of 48 patients were included in the study: 12 with tendinopathy, 12 with a partial-thickness tear (pRCT), 12 with a full-thickness tear (fRCT), and 12 as the control. A full-thickness supraspinatus tendon sample was harvested en bloc from the middle portion between the lateral edge and the musculotendinous junction of the tendon using a biopsy punch with a diameter of 3 mm. Harvested samples were evaluated using a semi-quantitative grading scale with 7 parameters after haematoxylin and eosin staining.

RESULTS

There was no significant difference in age, gender, symptom duration, and Kellgren-Lawrence grade between the groups except for the global fatty degeneration index. All of the seven parameters were significantly different between the groups and could be categorized as follows: early responders (fibre structure and arrangement), gradual responder (rounding of the nuclei), after-tear responders (cellularity, vascularity, and stainability), and late responder (hyalinization). The total degeneration scores were not significantly different between the control (6.08 ± 1.16) and tendinopathy (6.67 ± 1.83) (n.s.). However, the score of pRCT group (10.42 ± 1.31) was greater than that of tendinopathy (P < 0.001), and so was the score of fRCT (12.33 ± 1.15) than that of pRCT (p = 0.009).

CONCLUSION

This study showed that the degeneration of supraspinatus tendon increases as the stage of rotator cuff disease progresses from tendinopathy to pRCT, and then to fRCT. The degree of degeneration of tendinopathy was not different from that of normal but aged tendons, and significant tendon degeneration began from the stage of pRCT. The clinical relevance of the study is that strategies and goals of the treatment for rotator cuff disease should be specific to its stage, in order to prevent disease progression for tendinopathy and pRCT, as well to restore the structural integrity for fRCT.

LEVEL OF EVIDENCE

Diagnostic, Level I.

Preoperative NSAIDs, non-acute onset and long-standing symptoms predict inferior outcome at long-term follow-up after rotator cuff repair

PURPOSE

To evaluate mid- to long-term results after arthroscopic rotator cuff repair and to explore possible predictors of inferior outcome.

METHODS

Patients treated for full-thickness supraspinatus and/or infraspinatus tears from 2004 to 2008, using a uniform single-row arthroscopic technique, were included in the study. Pre- and post-operative QuickDASH were used as the primary outcome measure, and VAS of pain, function and satisfaction were also collected. An additional questionnaire explored demographic and preoperative factors like onset and duration of symptoms, preoperative treatment and smoking habits.

RESULTS

One hundred and forty-seven patients (82 %) were available at 6-9 years after surgery. All outcomes improved significantly from the preoperative values. A total of 8 % of patients had undergone additional surgery to the same shoulder during the follow-up period. Long-standing symptoms (>12 months) (P < 0.01), non-acute onset of symptoms (P < 0.01) and preoperative use of NSAIDs (P = 0.01) were correlated with inferior outcome at follow-up. No other factors investigated (i.e. gender, age, smoking and steroid injections) were found to affect the primary outcome (QuickDASH).

CONCLUSION

The current study is one of few reports of mid- to long-term outcomes after arthroscopic single-row repair of full-thickness rotator cuff tears. Global improvement in symptoms and function was found between the preoperative and the 6-9 years evaluation, and the technique therefore seems like a viable approach for treating tears of the supra- and the infraspinatus tendon. Several predictors of inferior long-term outcome after rotator cuff repair were, however, identified: preoperative use of NSAIDs, long-standing symptoms before surgery and non-acute onset of shoulder symptoms. In light of the current findings, accurate diagnosis and prompt treatment seem important in optimizing outcomes after rotator cuff surgery.

LEVEL OF EVIDENCE

IV.

A quantitative label-free analysis of the extracellular proteome of human supraspinatus tendon reveals damage to the pericellular and elastic fibre niches in torn and aged tissue

Tears of the human supraspinatus tendon are common and often cause painful and debilitating loss of function. Progressive failure of the tendon leading to structural abnormality and tearing is accompanied by numerous cellular and extra-cellular matrix (ECM) changes in the tendon tissue. This proteomics study aimed to compare torn and aged rotator cuff tissue to young and healthy tissue, and provide the first ECM inventory of human supraspinatus tendon generated using label-free quantitative LC-MS/MS. Employing two digestion protocols (trypsin and elastase), we analysed grain-sized tendon supraspinatus biopsies from older patients with torn tendons and from healthy, young controls. Our findings confirm measurable degradation of collagen fibrils and associated proteins in old and torn tendons, suggesting a significant loss of tissue organisation. A particularly marked reduction of cartilage oligomeric matrix protein (COMP) raises the possibility of using changes in levels of this glycoprotein as a marker of abnormal tissue, as previously suggested in horse models. Surprisingly, and despite using an elastase digestion for validation, elastin was not detected, suggesting that it is not highly abundant in human supraspinatus tendon as previously thought. Finally, we identified marked changes to the elastic fibre, fibrillin-rich niche and the pericellular matrix. Further investigation of these regions may yield other potential biomarkers and help to explain detrimental cellular processes associated with tendon ageing and tendinopathy.

Tendon functional extracellular matrix

This article is one of a series, summarizing views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the "Functional Extracellular Matrix" stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment, and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely varying extrinsic and intrinsic factors such as age, nutrition, exercise levels, and biomechanics. Consequently, tendon adapts dynamically during development, aging, and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair.