Strategies in biologic augmentation of rotator cuff repair: a review

Soluble allogeneic telocollagen as a direct protein therapeutic: results of serial injections in a rodent rotator cuff tear model

HYPOTHESIS

Delivery of soluble allogeneic type I telocollagen (allo-telocollagen) will accelerate and improve the healing of damaged tendons. Our hypothesis draws from known mechanochemical properties of type I collagen that direct its incorporation into damaged connective tissue. We further suggest that allo-telocollagen will raise a minimal immunogenic reaction as a result of homology within species.

METHODS

Seventy-eight shoulders (39 Sprague-Dawley rats) had their supraspinatus tendon surgically detached from its footprint on the humerus and repaired (72 shoulders) or left uninjured (6 shoulders). The repaired tissue was treated with an injection of 100 μL of saline, 10 mg/mL allogeneic atelocollagen (allo-atelocollagen), or 10 mg/mL allo-telocollagen at 0, 1, and 2 weeks postsurgery. At 30 and 60 days postsurgery, the tendons were assessed by mechanical testing (failure load, failure stress, stiffness, and relaxation) and by semiquantitative histologic scoring.

RESULTS

At 30 days postsurgery, the mechanical and histologic outcomes were not statistically different. However, at day 60, allo-telocollagen improved the failure strength of the supraspinatus (29.9 ± 4.7 N) relative to saline (20.0 ± 3.5 N, P < .001) or allo-atelocollagen (23.2 ± 1.5 N, P = .025) treated tendons, and it approached that of uninjured controls (36.9 ± 5.0 N, P = .021). Allo-telocollagen improved the failure stress of the supraspinatus (34.1 ± 9.3 MPa) relative to the saline-treated tendons (21.4 ± 6.0 MPa, P = .031, 160% improvement) and was no different than uninjured controls (33.4 ± 9.9 MPa, P = .999) or allo-atelocollagen (32.3 ± 7.4 MPa, P = .977). The stiffness of uninjured controls was far greater than any of injured or treated tendons (>200% stiffer). Histologic scoring showed that the allo-telocollagen-treated tendons produced better collagen fiber arrangement (1.55 ± 0.17) than saline (2.50 ± 0.29, P = .001) or allo-atelocollagen (2.23 ± 0.28, P = .042) treated tendons and that it did not increase markers of immunogenesis (1.10 ± 0.42) relative to either saline (1.44 ± 0.20, P = .369) or allo-atelocollagen (0.68 ± 0.41, P = .1058).

CONCLUSIONS

Although all 3 treatments produced similar results at 30 days, by 60 days, soluble allo-telocollagen clearly separated from the other interventions, yielding better mechanical and histologic outcomes in a torn or repaired rotator cuff rat model. Allo-telocollagen-treated tendons also approached the failure strength and matched the failure stresses of uninjured control tendons. The data suggest a new use for allo-telocollagen as a deliverable direct protein mechanotherapeutic that can improve both healing quality and speed.

The continuous fragility index of outcomes in rotator cuff repair augmentation randomized trials: a systematic review

BACKGROUND

Symptomatic rotator cuff tears often undergo surgical repair, which may be paired with various augmentation strategies to enhance structural healing rates. While many randomized controlled trials (RCTs) evaluate augmentation techniques, the statistical robustness of many findings in these studies is unknown. This systematic review aims to evaluate the continuous fragility index (CFI) of RCTs on augmentation techniques for rotator cuff repairs.

METHODS

MEDLINE, Embase, and CENTRAL databases were comprehensively searched from inception to September 2023 for RCTs assessing the efficacy of at least 1 augmentation strategy during rotator cuff repair. Eligible studies reported at least 1 statistically significant finding for a continuous outcome. The CFI for eligible outcomes was calculated, with median CFI presented by type of augmentation and outcome. Multivariable regression was performed to identify associations between CFI and other outcome variables.

RESULTS

Nineteen RCTs (1305 patients) were included in the final analysis. The median CFI for the 86 outcomes analyzed was 5.85 (interquartile range [IQR]: 2.3-14.4). Augmentation-specific analysis demonstrated variability in CFIs, with the most robust outcomes found in platelet-rich plasma studies (median: 10.95; IQR: 3.3-19.0) and suture-spanning augmentation studies (median: 11.90; IQR: 11.45-14.35). Outcome-specific analysis demonstrated range of motion outcomes as most robust (median: 9.85; IQR: 7.58-14.0) and strength-related outcomes as most fragile (median: 2.00; IQR: 1.0-16.3). Multivariable regression identified larger sample size as a statistically significant predictor of greater CFI. Notably, loss to follow-up exceeded the CFI in 31.4% of outcomes.

CONCLUSION

The observed median CFI of 5.85 in augmentation trials is consistent with the CFI reported in orthopedic and sports medicine literature. However, almost a third of outcomes had a loss to follow-up exceeding their CFI, risking the reversal of study findings with more robust follow-up and outcomes. Clinicians and researchers should consider fragility in addition to P values when assessing study results, especially in the context of high loss to follow-up. Future trials should report the fragility of their findings.

The Clinical Application of Gel-Based Composite Scaffolds in Rotator Cuff Repair

Rotator cuff tears are a common injury that can be treated with or without surgical intervention. Gel-based scaffolds have gained significant attention in the field of tissue engineering, particularly for applications like rotator cuff repair. Scaffolds can be biological, synthetic, or a mixture of both materials. Collagen, a primary constituent of the extracellular matrix (ECM) in musculoskeletal tissues, is one of the most widely used materials for gel-based scaffolds in rotator cuff repair, but other ECM-based and synthetic-based composite scaffolds have also been utilized. These composite scaffolds can be engineered to mimic the biomechanical and biological properties of natural tissues, supporting the healing process and promoting regeneration. Various clinical studies examined the effectiveness of these composite scaffolds with collagen, ECM and synthetic polymers and provided outstanding results with remarkable improvements in range of motion (ROM), strength, and pain. This review explores the material composition, manufacturing process and material properties of gel-based composite scaffolds as well as their clinical outcomes for the treatment of rotator cuff injuries.

Reverse total shoulder arthroplasty for acute proximal humeral fracture has comparable 10-year outcomes to elective indications: results from the New Zealand Joint Registry

HYPOTHESIS AND BACKGROUND

Recently, the indication of reverse total shoulder arthroplasty (RTSA) has expanded beyond rotator cuff arthropathy to include treatment of complex acute proximal humeral fracture (PHF). Limited previous studies have compared the long-term clinical and functional outcomes of patients undergoing RTSA for PHF vs. elective indications for degenerative conditions. The purpose of this study was to compare implant survivorship, reasons for revision and functional outcomes in patients undergoing RTSA for acute PHF with those undergoing elective RTSA in a population-based cohort study.

METHODS

Prospectively collected data from the New Zealand Joint Registry from 1999 to 2021 and identified 6862 patients who underwent RTSA. Patients were categorized by preoperative indication, including PHF (10.8%), rotator cuff arthropathy (RCA) (44.5%), osteoarthritis (OA) (34.1%), rheumatoid arthritis (RA) (5.5%), and old traumatic sequelae (5.1%). Revision-free implant survival and functional outcomes (Oxford Shoulder Scores [OSSs] at the 6-month, 5-year, and 10-year follow-ups) were adjusted by age, sex, American Society of Anesthesiologists class, and surgeon experience and compared.

RESULTS

Revision-free implant survival at 10 years for RTSA for PHF was 97.3%, compared with 96.1%, 93.7%, 92.8%, and 91.3% for OA, RCA, RA and traumatic sequelae, respectively. When compared with RTSA for PHF, the adjusted risk of revision was significantly higher for traumatic sequelae (hazard ratio = 2.3, P = .023) but not for other elective indications. The most common reason for revision in the PHF group was dislocation or instability (42.9%), which was similar to the OA (47.6%) and traumatic sequelae (33.3%) groups. At 6 months post-surgery, OSSs were significantly lower for the PHF group compared with the RCA, OA, and RA groups (31.1 vs. 35.6, 37.7, and 36.5, respectively, P < .001), and similar to traumatic sequelae (31.7, P = .431). At 5 years, OSSs were only significantly lower for PHF compared with OA (37.4 vs. 41.0, P < .001) and there was no difference between the PHF and other groups. At 10 years, there were no significant differences between groups.

CONCLUSIONS

RTSA for PHF demonstrated reliable long-term survivorship and functional outcomes compared with elective indications. Despite lower functional outcomes in the early postoperative period for the PHF group, implant survivorship was similar in patients undergoing RTSA for the primary indication of acute PHF compared with RCA, OA, and RA and superior compared to the primary indication of traumatic sequelae.

Analysis of differentially expressed genes in torn rotator cuff tendon tissues in diabetic patients through RNA-sequencing

BACKGROUND

Rotator cuff tears (RCT) is a common musculoskeletal disorder in the shoulder which cause pain and functional disability. Diabetes mellitus (DM) is characterized by impaired ability of producing or responding to insulin and has been reported to act as a risk factor of the progression of rotator cuff tendinopathy and tear. Long non-coding RNAs (lncRNAs) are involved in the development of various diseases, but little is known about their potential roles involved in RCT of diabetic patients.

METHODS

RNA-Sequencing (RNA-Seq) was used in this study to profile differentially expressed lncRNAs and mRNAs in RCT samples between 3 diabetic and 3 nondiabetic patients. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis were performed to annotate the function of the differentially expressed genes (DEGs). LncRNA-mRNA co-expression network and competing endogenous RNA (ceRNA) network were constructed to elucidate the potential molecular mechanisms of DM affecting RCT.

RESULTS

In total, 505 lncRNAs and 388 mRNAs were detected to be differentially expressed in RCT samples between diabetic and nondiabetic patients. GO functional analysis indicated that related lncRNAs and mRNAs were involved in metabolic process, immune system process and others. KEGG pathway analysis indicated that related mRNAs were involved in ferroptosis, PI3K-Akt signaling pathway, Wnt signaling pathway, JAK-STAT signaling pathway and IL-17 signaling pathway and others. LncRNA-mRNA co-expression network was constructed, and ceRNA network showed the interaction of differentially expressed RNAs, comprising 5 lncRNAs, 2 mRNAs, and 142 miRNAs. TF regulation analysis revealed that STAT affected the progression of RCT by regulating the apoptosis pathway in diabetic patients.

CONCLUSIONS

We preliminarily dissected the differential expression profile of lncRNAs and mRNAs in torn rotator cuff tendon between diabetic and nondiabetic patients. And the bioinformatic analysis suggested some important RNAs and signaling pathways regarding inflammation and apoptosis were involved in diabetic RCT. Our findings offer a new perspective on the association between DM and progression of RCT.

MicroRNA expression changes in the development of rotator cuff tendon injuries

Traumatic or degenerative rotator cuff (RC) tendon injuries are a leading cause of persistent shoulder pain and reduction of mobility with associated disability and dysfunction, which require each year more than 250,000 surgical repairs in the United States. MicroRNAs (miRNAs) are small noncoding RNAs, that in the posttranscriptional phase lead to the development and function of tissues. The aim of this review was to identify miRNA expression changes in patients with RC pathologies and to determine their relevance as a potential novel diagnostic and potentially therapeutic tool for RC disorders. Various miRNAs seemed to be key regulators in the muscle architecture, determining several modifications in muscle atrophy, skeletal muscle mechanical adaptation, lipid accumulation, and fibrosis in the presence of RC tears. The search was executed using PubMed, Medline, Scopus, and Cochrane Central. We included studies written in English that evaluated the role of miRNA in diagnosis, physiopathology, and potential therapeutic application of RC tendon injuries. We included 11 studies in this review. Many miRNAs emerged as key regulators in the pathogenesis of RC tears, inflammation, and muscle fatty degeneration. In fact, they are involved in the regulation of myogenesis, inflammatory cytokines, metalloproteases expression, muscle adaptation, adipogenesis, fibrogenic factors, and extracellular matrix synthesis. The gene expression may be altered in the pathological processes of tendon lesions. Therefore, the knowledge of all the gene mechanisms underlying RC tendinopathy should be achieved with future diagnostic and clinical studies.

TGF-β1 stimulated mesenchymal stem cells-generated exosomal miR-29a promotes the proliferation, migration and fibrogenesis of tenocytes by targeting FABP3

BACKGROUND

Rotator cuff Tear (RCT) causes a lot of inconvenience for patients. In most cases, RCT injury does not heal back to bone after repair, and there is a high chance of retearing. Therefore, there is a need to explore more effective targeted therapies. Bone mesenchymal stem cell-derived exosome (BMSCs-Exo) has been proved to be beneficial to the proliferation of tendon cells, but its specific mechanism remains to be further explored.

METHODS

BMSCs-Exo was isolated and identified by detecting the specific markers using flow cytometry and western blot assays. qRT-PCR and western blot were utilized to determine the gene or protein expressions, respectively. Cell proliferation, and migration in tenocytes were measured by CCK8, EdU and transwell assays. The interaction between miR-29a and FABP3 was analyzed using dual-luciferase reporter assay.

RESULTS

Our findings demonstrated that miR-29a was expressed in BMSCs-Exo and could be significantly enriched after TGF-β1 treatment. Moreover, TGF-β1-modified BMSCs-Exo co-cultured could promote the proliferation, migration and fibrosis of tenocytes by carrying miR-29a. Upon miR-29a was reduced in BMSCs-Exo, the regulatory roles of BMSCs-Exo on tenocytes were reversed. Mechanistically, miR-29a negatively regulated FABP3 via interaction with its 3'-UTR. Enforced expression of FABP3 could reverse the modulation of exosomal miR-29a in tenocytes.

CONCLUSION

Exosomal miR-29a derived from TGF-β1-modified BMSCs facilitated the proliferation, migration and fibrosis of tenocytes through targeting FABP3.

The Effect of PRP Augmentation of Arthroscopic Repairs of Shoulder Rotator Cuff Tears on Postoperative Clinical Scores and Retear Rates: A Systematic Review and Meta-Analysis

The aim of this review and meta-analysis is to assess recent clinical trials concerning the combination of operative treatment of rotator cuff tears and the administration of PRP and its effect on clinical scores and postoperative retear rates. The trials were used to compare the combination of PRP treatment and arthroscopic rotator cuff repair to arthroscopy alone. Twenty-five clinical trials were reviewed. A risk-of-bias assessment was made for all randomized clinical trials included, using the Cochrane collaboration’s tool as well as a quality assessment for all non-randomized studies utilizing the Newcastle−Ottawa scale. The PRP-treated patients showed statistically significant improvement postoperatively compared to control groups concerning the Constant−Murley (mean difference 2.46, 95% CI 1.4−3.52, p < 0.00001), SST (mean difference 0.32, 95% CI 0.02−0.63, p = 0.04), and UCLA (mean difference 0.82, 95% CI 0.23−1.43, p = 0.07) scores. A statistically significant decrease of retear rates in the PRP-treated patients, with a risk ratio of 0.78 (95% CI 0.65−0.94, p = 0.01), was found. We believe that the results presented have positive aspects, especially concerning the retear risk, but are yet inconclusive concerning clinical results such as shoulder pain and function.

Subacromial bursa increases the failure force in a mouse model of supraspinatus detachment and repair

BACKGROUND

It has been shown that subacromial bursa (SAB) harbors connective tissue progenitor cells. The purpose of this study was to evaluate the effects of implantation of SAB-derived cells (SBCs) suspended in a fibrin sealant bead and implantation of SAB tissue at rotator cuff repair site on biomechanical properties of the repair in a mouse (C57Bl/6) model of supraspinatus tendon (ST) detachment and repair.

METHODS

Part 1: Murine SAB tissue was harvested and cultured. Viability of SBCs suspended in 10 μL of fibrin sealant beads was confirmed in vitro and in vivo. Eighty mice underwent right ST detachment and repair augmented with either fibrin sealant bead (control group) or fibrin sealant bead with 100,000 SBCs (study group) applied at the repair site. Part 2: 120 mice underwent right ST detachment and repair and were randomized equally into 4 groups: (1) a tissue group, which received a piece of freshly harvested SAB tissue; (2) a cell group, which received SBCs suspended in fibrin sealant bead; (3) a fibrin sealant group, which received plain fibrin sealant bead without cells; and (4) a control group, which received nothing at the ST repair site. An equal number of mice in each group were killed at 2 and 4 weeks. Specimens underwent biomechanical testing to evaluate failure force (part 1 and 2) and histologic analysis of the repair site (part 1 only).

RESULTS

Part 1: The mean failure force in the study group was significantly higher than controls at 2 and 4 weeks (3.25 ± 1.03 N vs. 2.43 ± 0.56 N, P = .01, and 4.08 ± 0.99 N vs. 3.02 ± 0.8 N, P = .004, respectively). Mean cell density of the ST at the repair site was significantly lower in the study group at 2 weeks than in controls (18,292.13 ± 1706.41 vs. 29,501.90 ± 3627.49, P = .001). Study group specimens had lower proteoglycan contents than controls, but this difference was not statistically significant. Part 2: There was no difference in failure force between cell and tissue groups at the 2- and 4-week time points (P = .994 and P = .603, respectively). There was no difference in failure force between fibrin sealant bead and control groups at the 2- and 4-week time points (P = .978 and P = .752, respectively).

CONCLUSION

This study shows that the application of SBCs and SAB tissue at the rotator cuff repair site increases the strength of repair in a murine model of rotator cuff detachment and repair.

Genome-Wide Association Study Identifies Genetic Variants Associated with Rotator Cuff Tear-A Pilot Study

A rotator cuff is a muscle and tendon surrounding the shoulder joint, and a rotator cuff tear can be caused by overuse or injury, which leads to great pain in affected individuals. However, rotator cuff tear is a multifactorial process whose underlying mechanism is still unclear. Many previous studies have suggested an important role of genetic predisposition, such as single-nucleotide polymorphisms (SNPs), in explaining the genesis of tendinopathy. This study aimed to identify specific genes or genetic variants associated with rotator cuff tears by performing a genome-wide association study (GWAS) using an independent case of rotator cuff tears. GWAS was performed using data from CHA Bundang Medical Center with 20 cases of rotator cuff tears, and 20 cases of healthy controls genotyped on the Illumina HiSeq 2500. Tests of association were performed using the Burrows−Wheeler Aligner (BWA) software at 284,246 SNPs. Data were filtered based on sequence ontology, minor allele frequency, and Hardy−Weinberg equilibrium values, and SNPs were considered significant if the p-value was <0.05. The tests of association revealed more than 20 significantly associated SNPs. SNPs showing the highest significance occurred in candidate genes, including LAIR2 (rs2287828, OR 9.116, p-value 5.49 × 10−4) on chromosome 19 and CRIPAK (rs9328733, OR 6, p-value 1.11 × 10−3) and REST (rs2228991, OR 8.222, p-value 1.20 × 10−3) on chromosome 4. This study attempted to identify genetic variants influencing rotator cuff tears through a genome-wide association study using a dense set of SNPs. More than 20 SNPs were significantly associated with rotator cuff tears. The major limitation of this study is that it was conducted on a small study group and requires further validation. Nevertheless, the identification of potential genetic variants related to rotator cuff injury would aid in the early detection of individuals at risk for the development of tendinopathy and will provide insight into future gene therapies.

Hybprinting for musculoskeletal tissue engineering

This review presents bioprinting methods, biomaterials, and printing strategies that may be used for composite tissue constructs for musculoskeletal applications. The printing methods discussed include those that are suitable for acellular and cellular components, and the biomaterials include soft and rigid components that are suitable for soft and/or hard tissues. We also present strategies that focus on the integration of cell-laden soft and acellular rigid components under a single printing platform. Given the structural and functional complexity of native musculoskeletal tissue, we envision that hybrid bioprinting, referred to as hybprinting, could provide unprecedented potential by combining different materials and bioprinting techniques to engineer and assemble modular tissues.

Safety and Efficacy of Embolization with Microspheres in Chronic Refractory Inflammatory Shoulder Pain: A Pilot Monocentric Study on 15 Patients

Purpose: Musculoskeletal (MSK) embolization is emerging in tendinopathy treatment. The objective of this study was to assess the efficacy and safety of MSK embolization with microspheres in the treatment of chronic shoulder pain. Patients and methods: This retrospective monocentric study included patients with chronic shoulder pain resistant to 6 months or more of conventional therapies who were treated with MSK embolization between 2017 and 2021. Embolization was performed using calibrated 100–250 µm microspheres. Clinical success was defined as pain reduction, i.e., a decrease in the visual analogue scale (VAS) pain score of ≥50% at 3 months after MSK embolization as compared to baseline. Adverse events were collected. Results: Fifteen patients (11 women, 4 men) were included, with a median age of 50.3 years (IQR: 46.7–54.5). The median duration of symptoms was 26.6 months (20.6–39.8). The median VAS pain scores were 7.0 (7.0–8.0) at baseline, 6.0 (3.5–7.0) at 1 month, 5.0 (4.5–6.5) and 5.0 (3.0–7.4) at 3 months and 6 months (p = 0.002). Three patients (20%) reported clinical success at 3 months. Three patients experienced minor complications after embolization (paresthesia, n = 2; transient osteo-medullary edema, n = 1) and two patients had moderate complications (transient skin ischemia). Conclusion: MSK embolization with microspheres for treatment of refractory chronic shoulder pain showed moderate results in terms of clinical success and safety.

Repair of Lafosse I subscapularis injury adds no additional value in anterosuperior rotator cuff injury

Background

The study aimed to explore the additional value of repair of Lafosse I subscapularis injury compared with debridement in anterosuperior rotator cuff injury.

Methods

The prospective study was conducted on a total of 41 patients with supraspinatus tendon tear combined with Lafosse I subscapularis injury. Eighteen patients were divided into the repair group and 23 patients were divided into the non-repair group. The two groups were compared for intraoperative parameters, pain score, range of motion of the shoulder joint, shoulder joint function and quality of life (QoL) at pre-operation, 3 and 6 months postoperatively and the final follow-up visit.

Results

The width of supraspinatus tendon tear did not exceed 3 cm and did not retract beyond the glenoid in among patients. There was no statistical difference of preoperative data between two groups, including age, course of disease, positive Jobe test, positive Bear-hug test, positive Lift-off test, Patte stage, longitudinal tear and pain severity (P > 0.05). Compared to preoperative levels, the severity of pain, ASES scores and EQ-5D-3L scores were significantly lower at 3 and 6 months postoperatively and the final position (P < 0.05). However, there was no statistical difference in pain severity, ASES scores and EQ-5D-3L scores between repair group and non-repair group (P > 0.05). Similarly, compared to preoperative levels, the range of motion of shoulder joint was significantly improved after operation, including internal rotation, external rotation, forward flexion and elevation (P < 0.05). However, there was no statistical difference in range of motion of shoulder joint between repair group and non-repair group (P > 0.05).

Conclusion

Operative treatment can effectively lessen severity of pain in the patients, improve shoulder joint function, increase the range of motion of the shoulder joint and enhance the QoL in treating anterosuperior rotator cuff injury. However, repair of subscapularis brings no benefit compared to debridement in treating supraspinatus tendon tear combined with Lafosse I subscapularis injury.

Unsupervised Machine Learning-Based Analysis of Clinical Features, Bone Mineral Density Features and Medical Care Costs of Rotator Cuff Tears

Purpose

We aim to present unsupervised machine learning-based analysis of clinical features, bone mineral density (BMD) features, and medical care costs of Rotator cuff tears (RCT).

Patients and Methods

Fifty-three patients with RCT were reviewed, the clinical features, BMD features, and medical care costs were collected and analyzed by descriptive statistics. Furtherly, unsupervised machine learning (UML) algorithm was used for dimensionality reduction and cluster analysis of the RCT data.

Results

There were 26 males and 27 females. The patients were divided into four subgroups using the UML algorithm. There were significant differences among four subgroups regarding trauma exposure, full-thickness supraspinatus tendon tears, infraspinatus tendon tear, subscapularis tendon tear, BMD distribution, medial row anchors, lateral row anchors, total medical care costs, and consumables costs. We observed the highest frequency of trauma exposure, infraspinatus tendon tear, subscapularis tendon tear, osteoporosis, the highest number of medial row anchors, lateral row anchors, total medical care costs, and consumables costs in subgroup II.

Conclusion

The unsupervised machine learning-based analysis of RCT can provide clinically meaningful classification, which shows good interpretability and contribute to a better understanding of RCT. The significance of the results is limited due to the small number of samples, a larger follow-up study is needed to confirm the encouraging results.

Arthroscopic knotless repair: an effective technique for small-sized supraspinatus tendon tears

PURPOSE

The purpose was to evaluate the clinical and radiological results of knotless repair with flat-braided suture in full small-sized supraspinatus tendon tears (< 1 cm).

METHODS

A consecutive series of 54 patients with isolated small supraspinatus tendon tear (< 1 cm and Goutallier index < 2) was evaluated in the study. Patients underwent a knotless arthroscopic repair using flat-braided suture (2 mm wide). Minimal follow-up required was 5 years. Changes in Murley-Constant score, ASES score, strength, and pain relief were assessed. The Sugaya score was used to confirm the tendon repair on MRI. Data were analyzed in two subgroups: technique with additional U point for dog ear deformity (group 1) and technique without additional U point (group 2). The immobilization period was 3 weeks long. Passive mobilization was immediate.

RESULTS

Fifty-four patients were included. Mean age was 57 ± 4 years. The average follow-up was 68 ± 10 months. Average preoperative score of Constant was 51.2 ± 8.5 and 83.1 ± 14.6 at the end of the follow-up (p < 0.001). Mean VAS went from 5.8 ± 1.8 to 1.9 ± 2.1 (p < 0.001). Average forward elevation of the shoulder went from 86.3° ± 9 preoperatively to 169.6° ± 15.9 at the end of the follow-up (p < 0.001). The strength score was significantly higher post-operatively (18.4 vs. 8.3, p < 0.001.). The ASES score was significantly improved 49.1 ± 13.1 vs. 88.6 ± 15.8, p < 0.001). The MRI assessment revealed 94% of Sugaya 1-2. No significant difference was observed between group 1 and 2 regarding all clinical outcomes. Two complex regional pain syndromes were described with a favorable evolution. Three patients presented a retear requiring an iterative arthroscopic repair.

CONCLUSION

The use of a knotless arthroscopic construct with flat-braided suture for small supraspinatus repair achieved excellent structural and clinical results. This technique is fully adequate for the arthroscopic treatment of such tears, enabling early mobilization.

LEVEL OF EVIDENCE

Level III.

Effect of Exercise Intensity on the Healing of the Bone-Tendon Interface: A Mouse Rotator Cuff Injury Model Study

BACKGROUND

Injuries at the bone-tendon interface (BTI) are common findings in clinical practice. Rehabilitation procedures after BTI surgery are important but are controversial.

PURPOSE

To investigate the effects of different exercise intensities on BTI healing by means of an established mouse rotator cuff injury model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 150 specific pathogen free male C57BL/6 mice, with supraspinatus insertion injury, were randomly assigned to 1 of 5 groups according to postoperative rehabilitation of different exercise intensities: (1) control group, (2) low-intensity exercise group, (3) moderate-intensity exercise group, (4) high-intensity exercise group, and (5) increasing-intensity exercise group (IG). The specimens were harvested 4 or 8 weeks postoperatively for microarchitectural, histological, molecular biological, and mechanical evaluations.

RESULTS

Histological test results showed that the degrees of tissue fusion and polysaccharide protein distribution at the healing interface at 4 and 8 weeks after surgery were significantly better in the IG than in the other 4 groups. Synchrotron radiation micro-computed tomography showed that the quantity of subchondral bone at the enthesis (bone volume/total volume fraction, trabecular thickness, trabecular number) was higher and trabecular separation was lower in the IG than in the other 4 groups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the healing interface in the IG expressed more transcription factors, such as sox 9, runx 2, and scleraxis, than the interfaces in the other groups. Although no significant difference was seen in the cross-sectional area between the groups at postoperative weeks 4 and 8 (P > .05), the tensile load, ultimate strength, and stiffness of the specimens in the IG were significantly better than those in the other 4 groups (P < .05).

CONCLUSION

The rehabilitation program with increasing-intensity exercise was beneficial for BTI healing.

CLINICAL RELEVANCE

The results of this study provide evidence supporting the use of a simple and progressive exercise rehabilitation program after rotator cuff surgery.

Hierarchically Demineralized Cortical Bone Combined With Stem Cell-Derived Extracellular Matrix for Regeneration of the Tendon-Bone Interface

BACKGROUND

Poor healing of the tendon-bone interface after rotator cuff repair is one of the main causes of surgical failure. Previous studies demonstrated that demineralized cortical bone (DCB) could improve healing of the enthesis.

PURPOSE

To evaluate the outcomes of hierarchically demineralized cortical bone (hDCB) coated with stem cell-derived extracellular matrix (hDCB-ECM) in the repair of the rotator cuff in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Tendon-derived stem cells (TDSCs) were isolated, cultured, and identified. Then, hDCB was prepared by the graded demineralization procedure. Finally, hDCB-ECM was fabricated via 2-week cell culture and decellularization, and the morphologic features and biochemical compositions of the hDCB-ECM were evaluated. A total of 24 rabbits (48 samples) were randomly divided into 4 groups: control, DCB, hDCB, and hDCB-ECM. All rabbits underwent bilateral detachment of the infraspinatus tendon, and the tendon-bone interface was repaired with or without scaffolds. After surgery, 8 rabbits were assessed by immunofluorescence staining at 2 weeks, and the others were assessed by micro-computed tomography (CT) examination, immunohistochemical staining, histological staining, and biomechanical testing at 12 weeks.

RESULTS

TDSCs were identified to have universal stem cell characteristics including cell markers, clonogenicity, and multilineage differentiation. The hDCB-ECM contained 3 components (bone, partial DCB, and DCB coated with ECM) with a gradient of calcium and phosphorus elements, and the ECM had stromal cell-derived factor 1, biglycan, and fibromodulin. Macroscopic observations demonstrated the absence of infection and rupture around the enthesis. The results of immunofluorescence staining showed that hDCB-ECM promoted stromal cell recruitment. Results of micro-CT analysis, immunohistochemical staining, and histological staining showed that hDCB-ECM enhanced bone and fibrocartilage formation at the tendon-bone interface. Biomechanical analysis showed that the hDCB-ECM group had higher ultimate tensile stress and Young modulus than the DCB group.

CONCLUSION

The administration of hDCB-ECM promoted healing of the tendon-bone interface.

CLINICAL RELEVANCE

hDCB-ECM could provide useful information for the design of scaffolds to repair the tendon-bone interface, and further studies are needed to determine its effectiveness.

The effect of the platelet-rich plasma and ozone therapy on tendon-to-bone healing in the rabbit rotator cuff repair model

Background

The aim of this study is to histologically and biomechanically investigate the effects of local PRP and ozone therapy (O₂O₃) on tendon-to-bone healing in a rabbit model of the supraspinatus tendon tear.

Methods

Four groups were formed to have seven rabbits in each group: repair, R; repair + PRP, RP; repair + ozone, RO; and repair + PRP + ozone, RPO. The supraspinatus tendon was detached by sharp dissection from the footprint and an acute tear pattern was created. Thereafter, tendon repair was performed with the transosseous technique. In the RP group, PRP, and in the RPO group, PRP + O2O3 mixture was injected to the tendon repair site. In the RO group, O₂O₃ gas mixture was injected into subacromial space three times a week for a total of 4 weeks. The study was ended at postoperative 6th week.

Results

When compared with the R group, a statistically significant increase was observed in the biomechanical strength of the RP and RPO groups. The highest increase in biomechanical strength was detected in the RPO group. The histology of the RO and RPO groups showed better collagen fiber continuity and orientation than the R and RP groups.

Conclusions

The results obtained from this study show that the ozonized PRP can be used as biological support to increase tendon-to-bone healing. However, these results need to be supported by clinical studies.

Nanofiber Scaffolds by Electrospinning for Rotator Cuff Tissue Engineering

Rotator cuff tears continue to be at risk of retear or failure to heal after surgical repair, despite the use of various surgical techniques, which stimulate development of novel scaffolding strategies. They should be able to address the known causes of failure after the conventional rotator cuff repair: (1) failure to reproduce the normal tendon healing process, (2) resultant failure to reproduce four zones of the enthesis, and (3) failure to attain sufficient mechanical strength after repair. Nanofiber scaffolds are suited for this application because they can be engineered to mimic the ultrastructure and properties of the native rotator cuff tendon. Among various methods for tissue-engineered nanofibers, electrospinning has recently been highlighted in the rotator cuff field. Electrospinning can create fibrous and porous structures that resemble natural tendon's extracellular matrix. Other advantages include the ability to create relatively large surface-to-volume ratios, the ability to control fiber size from the micro to the nano scale, and the flexibility of material choices. In this review, we will discuss the anatomical and mechanical features of the rotator cuff tendon, their potential impacts on improper healing after repair, and the current knowledge of the use of electrospinning for rotator cuff tissue engineering.

Application of biomimetic double-layer biofilm stent in arthroscopic rotator cuff repair: A protocol of randomized controlled trial

BACKGROUND

Rotator cuff injury is the most common cause of shoulder dysfunction. Despite the continuous advancement of surgical techniques, the incidence of re-tearing after rotator cuff repair is still high. The main reason is that it is difficult to reconstruct the normal tendon bone interface and the process is slow, and the application of tissue engineering technology can promote tendon and bone healing. This study will evaluate the effect of the bionic double membrane stent on the rotator cuff healing after arthroscopic rotator cuff repair.

METHODS

This is a prospective randomized controlled trial to study the effect of biomimetic double-layer biofilm stent on rotator cuff healing. Approved by the clinical research ethics committee of our hospital. The patients were randomly divided into 1 of 2 treatment options: (A) a biomimetic double-layer biofilm stent group and (B) a non-bionic dual-layer biofilm stent group. Observation indicators include: visual analog scale score, University of California Los Angeles score, American Shoulder & Elbow Surgeons score and Constant-Murley score. Data were analyzed using the statistical software package SPSS version 16.0 (Chicago, IL).

DISCUSSION

This study will evaluate and evaluate the effect of the bionic double-layer membrane stent on the rotator cuff healing after arthroscopic rotator cuff repair. The results of this experiment will provide new treatment ideas for promoting rotator cuff tendon bone healing.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/FWKD6.

Role of Platelet Rich Plasma (PRP) injection in treatment of rotator cuff tear

Background

One of the commonest causes of shoulder pain and disability is partial thickness tear of the rotator cuff. Platelet-rich plasma (PRP) therapy is a volume of the plasma fraction of autologous blood that has platelet concentration above the baseline. It is theorized that PRP may help stimulate the development of normal-appearing histologic tissue characteristics at the repair site and improve clinical outcomes. Our purpose is to assess the efficacy of PRP therapy in treatment of rotator cuff tear. This prospective single-center study involved 30 patients (aged 31.7 ± 7.7 years, 63.3% males) complaining of symptomatic rotator cuff tear. Platelet-rich plasma (PRP) injection was done to all patients. Before and after injection of PRP, scoring was done using visual analog score, Shoulder Pain and Disability Index (SPADI), and musculoskeletal ultrasound scoring of the tear. Reassessment was done 4 weeks after the injections.

Results

The pre-injection VAS pain score was 7.1 ± 0.99 after injection, and it became 3.7 ± 1.09. Also, SPADI score decreased from 78.03 ± 8.25 pre-injection to 42.1 ± 13.97 post-injection. There was a highly statistically significant difference in VAS pain score and SPADI score before and after PRP injection (p < 0.001). There was highly statistically significant positive correlation between the improvement of US grading score change and the improvement of VAS score change, and between it and SPADI improvement change (r = 0.695, p < 0.001 and r = 0.693, p < 0.001, respectively). There was a highly statistically significant difference between US grading score before and after PRP injection (p < 0.001).

Conclusion

PRP can be considered an effective method for treatment of rotator cuff tear and less invasive compared to surgical treatment. It improves the pain, shoulder function, and tear size.

Concurrent multi-lineage differentiation of mesenchymal stem cells through spatial presentation of growth factors

Severe tendon and ligament injuries are estimated to affect between 300 000 and 400 000 people annually. Surgical repairs of these injuries often have poor long-term clinical outcomes because of resection of the interfacial tissue-the enthesis-and subsequent stress concentration at the attachment site. A healthy enthesis consists of distinct regions of bone, fibrocartilage, and tendon, each with distinct cell types, extracellular matrix components, and architecture, which are important for tissue function. Tissue engineering, which has been proposed as a potential strategy for replacing this tissue, is currently limited by its inability to differentiate multiple lineages of cells from a single stem cell population within a single engineered construct. In this study, we develop a multi-phasic gelatin methacrylate hydrogel construct system for spatial presentation of proteins, which is then validated for multi-lineage differentiation towards the cell types of the bone-tendon enthesis. This study determines growth factor concentrations for differentiation of mesenchymal stem cells towards osteoblasts, chondrocytes/fibrochondrocytes, and tenocytes, which maintain similar differentiation profiles in 3D hydrogel culture as assessed by qPCR and immunofluorescence staining. Finally, it is shown that this method is able to guide heterogeneous and spatially confined changes in mesenchymal stem cell genes and protein expressions with the tendency to result in osteoblast-, fibrochondrocyte-, and tenocyte-like expression profiles. Overall, we demonstrate the utility of the culture technique for engineering other musculoskeletal tissue interfaces and provide a biochemical approach for recapitulating the bone-tendon enthesis in vitro.

Rotator Cuff Tear Susceptibility Is Associated With Variants in Genes Involved in Tendon Extracellular Matrix Homeostasis

Rotator cuff tears (RCT) is a multifactorial disease with genetic factors contributing for the disease etiology. We hypothesized that genetic variants in genes involved in extracellular matrix (ECM) homeostasis may alter susceptibility to RCT. We evaluated 20 polymorphisms of genes involved in ECM homeostasis in 211 cases of full-thickness tears of the supraspinatus (N_females  = 130; N_males  = 81) and 567 age-matched controls (N_females  = 317; N_males  = 250). Multivariate logistic regressions were carried out with age, gender, genetic ancestry (based on the analysis of 61 biallelic short insertion/deletion polymorphisms), and common co-morbidities (diabetes, dyslipidemia, and smoking habits) as covariates. We observed that carriers of the rare allele of both studied variants of TGFB1, as well as their G/A (rs1800470/rs1800469) haplotype, were less susceptible to RCT (p < 0.05). In contrast, carriers of the G allele of MMP9 rs17576 (p = 0.014) or G/G haplotype (rs17576/rs17577; p < 0.001) had an increased risk for tendon tears. The presence of the T allele of MMP2 rs2285053 (p = 0.033), the T allele of MMP3 rs679620 (p = 0.024), and the TT-genotype of TIMP2 rs2277698 (p = 0.01) was associated with susceptibility to tears, especially in females. In males, the A allele of COL5A1 rs3196378 (p = 0.032) and the G allele of TGFBR1 rs1590 (p = 0.039) were independent risk factors for RCT. The C/T COL5A1 (rs3196378/rs11103544) haplotype was associated with a reduced risk of tears in males (p = 0.03). In conclusion, we identified the genetic variants associated with RCT susceptibility, thereby reinforcing the role of genes involved in the structure and homeostasis of the ECM of tendons in disease development. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:192-201, 2020.

The clinical strategies for tendon repair with biomaterials: A review on rotator cuff and Achilles tendons

Tendon repair is a complex process due to the low tenocyte density, metabolism, and vascularization. Tears of rotator cuff (RCT) and Achilles tendons ruptures have a major impact on healthcare costs and quality of life of patients. Scaffolds are used to improve the healing rate after surgery and long-term results. A systematic search was carried out to identify the different types of scaffolds used during RCT and Achilles tendon repair surgery in the last 10 years. A higher number of clinical studies were reported on RCT ruptures. Biological scaffolds were used more than synthetic ones, for both rotator cuff and Achilles tendons. Moreover, platelet-rich plasma (PRP)-based scaffolds were the most widely used in RCT. A different type of synthetic scaffold was used in each of the five studies found. Biological scaffolds either provide variable results, in particular PRP-based ones, or poor results, such as bovine equine pericardium. All the synthetic scaffolds demonstrated a significant increase in clinical and functional scores in biomechanics, and a significant decrease in pain and re-tear rate in comparison to conventional surgery. Despite the limited number of studies, further investigation in the clinical use of synthetic scaffolds should be carried out.

The role of biologic agents in the management of common shoulder pathologies: current state and future directions

The field of orthopedic surgery has seen a rapid increase in the use of various biologic agents for the treatment of common musculoskeletal injuries. Most biologic agents attempt to harness or mimic naturally occurring growth factors, cytokines, and anti-inflammatory mediators to improve tissue healing and recovery. The most commonly used biologic agents are platelet-rich plasma and cells derived from bone marrow aspirate and adipose tissue. These agents have become increasingly popular despite a relative dearth of clinical data to support their use. Much confusion exists among patients and physicians in determining the role of these agents in treating common shoulder pathologies, such as glenohumeral osteoarthritis, rotator cuff tears, and tendinopathy. This article reviews the basic science and clinical evidence for the most commonly used biologic agents in the management of common shoulder pathology.

Arthroscopic Rotator Cuff Repair With Allograft Augmentation: Making It Simple

Rotator cuff tears are increasing in frequency in the aging population and are a common issue seen by orthopaedic surgeons. In patients with large, multi-tendon rotator cuff tears or retears, treatment can be challenging. Failure rates of up to 90% have been reported for rotator cuff repair (RCR) of large, multi-tendon tears. Biological augmentation has been an area of interest because of the distinctly different biology of the repaired tendon compared with the native tendon. These biological differences affect the ultimate tensile properties of the repair and may contribute to gap formation and the high failure rate of repairs. RCR with allograft augmentation is a technique that shows potential benefit to healing and preventing retears. Arthroscopic augmentation of RCRs can be challenging. The technique described in this Technical Note illustrates a simple and easily reproducible method for augmenting RCRs with human acellular dermal allograft.

Overlay repair with a synthetic collagen scaffold improves the quality of healing in a rat rotator cuff repair model

BACKGROUND

Augmenting repairs with extracellular matrix-based scaffolds is a common option for rotator cuff tears. In this study, a new collagen scaffold was assessed for its efficacy in augmenting rotator cuff repair.

METHODS

The collagen scaffold was assessed in vitro for cytocompatibility and retention of tenocyte phenotype using alamarBlue assays, fluorescent imaging, and real-time polymerase chain reaction. Immunogenicity was assessed in vitro by the activation of human monocytes. In vivo, by use of a modified rat rotator cuff defect model, supraspinatus tendon repairs were carried out in 40 animals. Overlay augmentation with the collagen scaffold was compared with unaugmented repairs. At 6 and 12 weeks postoperatively, the repairs were tested biomechanically to evaluate repair strength, as well as histologically to assess quality of healing.

RESULTS

The collagen scaffold supported human tendon-derived cell growth in vitro, with cells demonstrating proliferation and appearing morphologically tenocytic over the experimental period. No immunogenic responses were provoked compared with suture material control. In vivo, augmentation with the scaffold improved the histologic scores at 12 weeks (8.4 of 15 vs 6.4 of 15, P = .032). However, no significant difference was detected with mechanical testing.

CONCLUSION

The new collagen scaffold was supportive of cell growth in vitro and generated a minimal acute inflammatory response. In vivo, we observed an improvement in the histologic appearance of the repair at 12 weeks. However, a meaningful increase in biomechanical strength was not achieved. Further modification and improvement of the scaffold are required prior to consideration for clinical use.

Current Concepts and Recent Trends in Arthroscopic Treatment of Large to Massive Rotator Cuff Tears: A Review

Rotator cuff tear is a common cause of shoulder pain and disability in adults. Due to the various nature of progression of rotator cuff tears and the complex biomechanics of the shoulder joint, repair and treatment of large-to-massive tears are challenging for many surgeons. Despite the recent popularity of reverse total shoulder arthroplasty as a treatment option for large-to-massive irreparable rotator cuff tears, biological and mechanical repair augmentation has also shown promise as a viable treatment option. The purpose of this study was to briefly summarize and review current studies on the assessment and arthroscopic treatment of large-to-massive rotator cuff tears, whether repairable or irreparable, to aid in developing a consensus on future treatment directions.

Perioperative Serum 25-Hydroxyvitamin D Levels Affect Revision Surgery Rates After Arthroscopic Rotator Cuff Repair

PURPOSE

To examine any association between perioperative serum 25-hydroxyvitamin D levels and failure of arthroscopic rotator cuff repair (RCR) requiring revision surgery.

METHODS

Using a private-payer national insurance database, patients who underwent arthroscopic RCR with perioperative serum 25-hydroxyvitamin D levels recorded were included. Patients were stratified into groups of (1) serum 25-hydroxyvitamin D deficiency (<20 ng/mL), (2) insufficiency (20-30 ng/mL), or (3) sufficient (>30-<150 ng/mL). The primary outcome measure was ipsilateral revision rotator cuff surgery, including revision repair, debridement, or reverse shoulder arthroplasty. A multivariable logistic regression analysis was used to control for patient demographics and comorbidities during comparisons.

RESULTS

A total of 982 patients were included in the study. The rate of revision rotator cuff surgery was significantly higher in patients in the serum 25-hydroxyvitamin D-deficient group (5.88%) compared with the serum 25-hydroxyvitamin D-sufficient control group (3.7%) (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.6-5.8; P = .007). Patients with serum 25-hydroxyvitamin D deficiency (5.88%) also had a significantly higher incidence of revision surgery compared with patients with serum 25-hydroxyvitamin D insufficiency (OR, 2.4; 95% CI, 1.5-3.9; P = .011). There was no significant difference in the incidence of revision surgery in the serum 25-hydroxyvitamin D-insufficient group (4.97%) compared with the serum 25-hydroxyvitamin D-sufficient control group (3.7%) (OR, 1.4; 95% CI, 0.8-2.3; P = .250). The absolute risk reduction of revision surgery for 25-hydroxyvitamin D-deficient patients compared with controls was 2.2%, corresponding to a number needed to treat to avoid 1 revision surgery of 46 patients, relative risk reduction = 0.59.

CONCLUSIONS

Although the present study found a significant statistical association between serum 25-hydroxyvitamin D deficiency and insufficiency and the rate of revision rotator cuff surgery after primary arthroscopic RCR, the absolute differences of these revision rates are minimal and are accompanied with overlapping confidence intervals limiting the clinical significance of these findings.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Tissue-derived microparticles reduce inflammation and fibrosis in cornea wounds

Biological materials derived from the extracellular matrix (ECM) of tissues serve as scaffolds for rebuilding tissues and for improved wound healing. Cornea trauma represents a wound healing challenge as the default repair pathway can result in fibrosis and scar formation that limit vision. Effective treatments are needed to reduce inflammation, promote tissue repair, and retain the tissue's native transparency and vision capacity. Tissue microparticles derived from cornea, cartilage and lymph nodes were processed and screened in vitro for their ability to reduce inflammation in ocular surface cells isolated from the cornea stroma, conjunctiva, and lacrimal gland. Addition of ECM particles to the media reduced expression of inflammatory genes and restored certain tear film protein production in vitro. Particles derived from lymph nodes were then applied to a rabbit lamellar keratectomy corneal injury model. Application of the tissue particles in a fibrin glue carrier decreased expression of inflammatory and fibrotic genes and scar formation as measured through imaging, histology and immunohistochemistry. In sum, immunomodulatory tissue microparticles may provide a new therapeutic tool for reducing inflammation in the cornea and ocular surface and promoting tissue repair. STATEMENT OF SIGNIFICANCE: Damaged cornea will result in scar tissue formation that impedes vision, and new therapies are needed to enhance wound healing in the cornea and to prevent fibrosis. We evaluated the effects of biological scaffolds derived extracellular matrix (ECM) during corneal wound healing. These ECM particles reduced inflammatory gene expression and restored tear film production in vitro, and reduced scar formation and fibrosis genes in the wounded cornea, when applied to in vivo lamellar keratectomy injury model. The immunomodulatory tissue microparticles may provide a new therapeutic tool for reducing inflammation in the cornea and ocular surface and promoting proper tissue repair.

Platelet-Rich Plasma: Review of Current Literature on its Use for Tendon and Ligament Pathology

PURPOSE OF REVIEW

Platelet-rich plasma (PRP) contains numerous growth factors and cytokines that potentially offer an alternative treatment modality to assist in the healing of multiple musculoskeletal issues. The purpose of this review was to examine the latest literature on the use of PRP for various ligament and tendon pathologies.

RECENT FINDINGS

Recent literature has shown moderate- to high-quality evidence that PRP can have positive clinical effects in certain conditions such as lateral epicondylitis and rotator cuff tendinopathy. Prospective studies have shown that it can also be useful in the treatment of patella tendinopathy. In summary, we found PRP to have variable success in ligament and tendon pathology; however, it should be considered a viable option in chronic musculoskeletal disease that has failed other treatments. Patient selection, duration of symptoms, and combining with other modalities such as physical therapy should all be taken into consideration in treatment with PRP.

Obesity causes poorer clinical results and higher re-tear rates in rotator cuff repair

BACKGROUND

The purpose of this retrospective study was to report on the functional outcome after both open and arthroscopic rotator cuff (RC) repair in normal weight, pre-obese and obese patients. It was hypothesized that obesity is a negative prognostic factor for clinical outcome and failure for the RC repair.

METHODS

One hundred and forty-six patients who underwent either open or arthroscopic rotator cuff repair between 2006 and 2010 were included in this study. Seventy-five patients (56.7 ± 10.1 years of age) after open RC repair and 71 patients (59.0 ± 9.1 years of age) treated arthroscopically were available for evaluation. In both groups a double-row reconstruction was performed. Patients were divided in three groups according to their body-mass index. The mean follow-up was at 43 ± 16 (minimum 24) months. At follow-up, the clinical outcome was assessed by the DASH and Constant score. An ultrasound of both shoulders was performed in all patients.

RESULTS

The mean BMI was 28.3 ± 5.3 in the arthroscopic group and 27.7 ± 4.3 in the open group. Overall, in both groups similar clinical results were noted [Constant-Murley score 78.3 ± 18.2 arthroscopic vs. 77.0 ± 21.8 for open surgery; DASH 12.7 ± 18.2 arthroscopic vs. 15.6 ± 21.6 for open surgery (p = 0.81)]. Both the failure rate and the clinical outcome were significantly worse for obese patients (BMI > 30, p = 0.007). The failure rate was 15.8% for the normal-weight patients, 8.2% in the pre-obese group and in the obese group 28.6%. The RC repair failure occurred in 11 cases in both groups after arthroscopic or open treatment (15.0%).

CONCLUSIONS

Both the arthroscopic and the open approach showed equivalent clinical results and failure rates. Obesity (BMI > 30) causes less favorable results in the Constant and DASH scores and showed higher re-tear rates.

Migration of Mesenchymal Stem Cells of Bursal Tissue after Rotator Cuff Repair in Rats

Purpose  The purpose of this study is to verify migration of mesenchymal stem cells of bursal tissue into the healing site after rotator cuff repair in rats. Methods  Fischer rats and green fluorescent protein (GFP)-transgenic rats were used. Bursal tissue from GFP rats was isolated and transplanted into tendon repair sites in Fischer rats. We examined the histology of the rotator cuff and the proportion of GFP-positive cells in the repaired rotator cuff 1, 3, and 6 weeks after surgery. Results  Cell migration was observed during the third and sixth week after surgery. We also found mesenchymal stem cells and formed bursal cluster patterns in the repaired rotator cuff tendons. Conclusion  Mesenchymal stem cells migrated from bursal tissue and infiltrated the repaired rotator cuff tendons. Clinical Relevance  Mesenchymal stem cells from bursal tissue can contribute to the healing progress of the repaired rotator cuff.

Enhanced Tendon-to-Bone Healing of Chronic Rotator Cuff Tears by Bone Marrow Aspirate Concentrate in a Rabbit Model

Background

To evaluate the influence of bone marrow aspirate concentrate (BMAC) on tendon-to-bone healing in a rabbit rotator cuff model and to characterize the composition of growth factors in BMAC.

Methods

In this in vivo study, 40 rabbits were allocated into five groups: control (C), repair + saline (RS), repair + platelet-rich plasma (PRP; RP), repair + BMAC (RB) and repair + PRP + BMAC (RPB). A tear model was created by supraspinatus tendon transection at the footprint. Six weeks after transection, the torn tendon was repaired along with BMAC or PRP administration. Six weeks after repair, shoulder samples were harvested for biomechanical and histological testing. Ten rabbits were used for processing PRP and BMAC, followed by analysis of blood cell composition and the levels of growth factors in vitro.

Results

The ultimate load-to-failure was significantly higher in RPB group compared to RS group (p = 0.025). BMAC-treated groups showed higher values of biomechanical properties than RS group. The histology of BMAC-treated samples showed better collagen fiber continuity and orientation than RS group. BMAC contained significantly higher levels of the several growth factors than PRP.

Conclusions

Locally administered BMAC enhanced tendon-to-bone healing and has potential for clinical applications.

Porcine Dermis Patch Augmentation of Supraspinatus Tendon Repairs: A Pilot Study Assessing Tendon Integrity and Shoulder Function 2 Years After Arthroscopic Repair in Patients Aged 60 Years or Older

PURPOSE

To investigate the 2-year postoperative clinical and subjective outcomes after arthroscopic rotator cuff repair (ARCR) with xenologous porcine dermal patch augmentation compared with ARCR alone.

METHODS

Patients aged 60 years or older with a complete supraspinatus (SSP) tendon tear underwent primary ARCR with a transosseous-equivalent technique. By use of a matched-pair comparative trial design, a consecutive series of 20 patients receiving additional xenologous porcine dermal patch augmentation (patch group) was matched by tear location with 20 patients who received ARCR only (control group). Prior conservative treatment failed in all patients. Patients with concomitant pathologies precluding accurate repair assessment, partial or open reconstruction, or a latissimus dorsi and/or pectoralis major muscle transfer were excluded. Patients reported daily pain levels for 10 days after surgery. Clinical parameters and various patient-reported outcome scores were documented preoperatively and at 3, 6, and 24 months after surgery. Repair integrity was determined by magnetic resonance imaging or ultrasound at 24 months. Adverse events were recorded. Group outcome differences were analyzed with t tests, Fisher exact tests, and mixed models.

RESULTS

Patients in both groups were aged 67 years on average (range, 60-74 years), and 70% of patients were men. Patients in the patch group had slightly more SSP fatty infiltration preoperatively. Patch surgical procedures were on average 22 minutes longer than control interventions (P = .003). At 24 months, 4 patients and 9 patients were diagnosed with a recurrent SSP tendon defect in the control group (n = 20) and patch group (n = 19), respectively (relative risk, 2.4; P = .096). Of 11 defects (85%) identified as medial cuff failure, 8 occurred in the patch group. Pain rated by all patients decreased from postoperative day 1 to day 10 without any significant group difference (P = .348). No significant group differences were noted for other outcome parameters, and recurrent defects had no relevant effect on functional outcomes. Local complications (including recurrent defects) occurred in 8 patients in the control group and 12 in the patch group (P = .343).

CONCLUSIONS

Our pilot study supports the view that an SSP tear repair with porcine dermal xenograft augmentation does not benefit patients in terms of reducing the risk of a recurrent tendon defect or improving shoulder function up to 24 months after surgical repair.

LEVEL OF EVIDENCE

Level III, therapeutic study, retrospective comparative trial.

Enhancement of rotator cuff tendon-bone healing with fibroblast growth factor 2 impregnated in gelatin hydrogel sheets in a rabbit model

BACKGROUND

Application of fibroblast growth factor 2 (FGF-2) may improve the healing response after rotator cuff (RC) surgical repair. This study aimed to determine whether FGF-2-impregnated gelatin hydrogel sheet (GHS) incorporation into the bony trough on the greater tuberosity facilitates healing after RC surgical repair in rabbits.

METHODS

We assigned 120 adult male Japanese white rabbits treated with unilateral surgery for supraspinatus tendon repair into the following groups: suture-only group (suture); suture and GHS with phosphate-buffered saline (carrier); suture and GHS with 3 µg of FGF-2 (F3); and suture and GHS with 30 µg of FGF-2 (F30). The effect of FGF-2 was assessed using histologic, biomechanical, and microcomputed tomography evaluations at 2, 6, and 12 weeks.

RESULTS

At 12 weeks, loose fibrovascular tissues emerged at the repair site in the suture and carrier groups and dense tendon-like tissues in the F3 and F30 groups, which demonstrated significantly higher ultimate load-to-failure and stress-to-failure at 12 weeks than that in the suture and carrier groups. Microcomputed tomography imaging showed ectopic calcification formation in some specimens from each group. Appearances or frequencies were similar among groups. The histologic and biomechanical effects of FGF-2 on RC healing were obvious at ≥6 weeks postoperatively.

CONCLUSION

FGF-2-impregnated GHS incorporation into the bony trough on the greater tuberosity before RC surgical repair is feasible and results in histologic and biomechanical improvements during RC healing in rabbits. No detrimental effect on ectopic calcification was observed.

Epigenetic regulation of metalloproteinases and their inhibitors in rotator cuff tears

Rotator cuff tear is a common orthopedic condition. Metalloproteinases (MMP) and their inhibitors (TIMP) seem to play a role in the development of joint injuries and in the failure of tissue healing. However, the mechanisms of regulation of gene expression in tendons are still unknown. Epigenetic mechanisms, such as DNA methylation and microRNAs regulation, are involved in the dynamic control of gene expression. Here, the mRNA expression and DNA methylation status of MMPs (MMP1, MMP2, MMP3, MMP9, MMP13, and MMP14) and TIMPs (TIMP1-3) and the expression of miR-29 family members in ruptured supraspinatus tendons were compared with non-injured tendons of individuals without this lesion. Additionally, the gene expression and methylation status at the edge of the ruptured tendon were compared with macroscopically non-injured rotator cuff tendon samples from the anterior and posterior regions of patients with tendon tears. Moreover, the possible associations between the molecular alterations and the clinical and histologic characteristics were investigated. Dysregulated expression and DNA methylation of MMP and TIMP genes were found across the rotator cuff tendon samples of patients with supraspinatus tears. These alterations were influenced at least in part by age at surgery, sex, smoking habit, tear size, and duration of symptoms. Alterations in the studied MMP and TIMP genes may contribute to the presence of microcysts, fissures, necrosis, and neovascularization in tendons and may thus be involved in the tendon healing process. In conclusion, MMPs and their inhibitors are regulated by epigenetic modifications and may play a role in rotator cuff tears.

Clinical Results of Platelet-Rich Plasma for Partial Thickness Rotator Cuff Tears: A Case Series

Partial thickness rotator cuff tears (PTRCTs) are a common pathology among shoulder disorders in people over 50 years. Treatment of PTRCTs remains controversial. Most studies on the treatment of PTRCTs have explained surgical techniques or outcomes; few studies have centralized on the conservative and new management of PTRCTs, like treatment with Platelet-rich plasma (PRP). These case series study have been conducted on Platelet-rich plasma (PRP) injection, as a concentrated source of cytokines that can stimulate healing of soft tissue. PRP injection showed positive effect on improving PTRCTs complains. This method improved pain, function, DASH score and shoulder joint range motion in. Because of PRP products are safe and easy to prepare and apply, and also according to improving patient's condition, this method can be used to treat PTRCTs.

Treatment of Partial Rotator Cuff Tear with Ultrasound-guided Platelet-rich Plasma

Background:

The treatment of symptomatic partial rotator cuff tear has presented substantial challenge to orthopaedic surgeons as it can vary from conservative to surgical repair. Researches have established the influence of platelet rich plasma in healing damaged tissue. Currently very few data are available regarding the evidence of clinical and radiological outcome of partial rotator cuff tear treated with ultrasound guided platelet rich plasma injection in English literature.

Materials and Methods:

20 patients with symptomatic partial rotator cuff tears were treated with ultrasound guided platelet rich plasma injection. Before and after the injection of platelet rich plasma scoring was done with visual analogue score, Constant shoulder score, and UCLA shoulder score at 8 weeks and third month. A review ultrasound was performed 8 weeks after platelet rich plasma injection to assess the rotator cuff status.

Results:

Our study showed statistically significant improvements in 17 patients in VAS pain score, constant shoulder score and UCLA shoulder score. No significant changes in ROM were noted when matched to the contra-lateral side (P < 0.001) at the 3 month follow-up. The study also showed good healing on radiological evaluation with ultrasonogram 8 weeks after platelet rich plasma injection.

Conclusion:

Ultrasound guided platelet rich plasma injection for partial rotator cuff tears is an effective procedure that leads to significant decrease in pain, improvement in shoulder functions, much cost-effective and less problematic compared to a surgical treatment.

Efficacy of bone marrow-stimulating technique in rotator cuff repair

BACKGROUND

This study used a chronic rotator cuff (RC) tear model to investigate the effect of microfracture as a bone marrow-stimulating (BMS) technique for RC healing.

METHODS

A chronic retracted RC tendon tear model was created bilaterally in the subscapularis tendons of 20 New Zealand rabbits. The tendons were repaired after 8 weeks using a single-row configuration. Tendons in the right shoulder were repaired in standard fashion (control group). Microfractures were performed in the left shoulders before repair (microfracture group). The animals were euthanized 8 and 16 weeks after repair. The repaired tendons were tested biomechanically for their ultimate failure load, linear stiffness, and elongation at failure. Gross and histologic evaluations of the tendon-to-bone healing were evaluated.

RESULTS

Macroscopically, subscapularis tendons were attached on the lesser tuberosity. In the microfracture group, collagen fibers were organized in relatively thicker bundles. The mean ultimate failure load of the microfracture group was significantly greater at 8 weeks (148.4 ± 31 N vs. 101.4 ± 26 N, respectively; P = .011) and 16 weeks (155 ± 30 N vs. 114.9 ± 25 N, respectively; P = .017) after repair. There were no significant differences between the groups for linear stiffness at 8 weeks (15.9 ± 2.7 N/mm vs. 15.8 ± 1.3 N/mm, respectively; P = .798) and 16 weeks (16.9 ± 4.3 N/mm vs. 17.1 ± 3.6 N/mm, respectively, P = .848) and elongation at failure at 8 weeks (4.7 ± 1.1 mm vs. 4.7 ± 1.3 mm, respectively; P = .848) and 16 weels (4.8 ± 1.5 mm vs. 4.9 ± 0.9 mm, respectively; P = .749).

CONCLUSION

The microfracture on the tuberosity of the repaired chronic rotator cuff tear promoted dynamic tendon healing with significantly increased ultimate force to failure and with thicker collagen bundles and more fibrocartilage histologically at 8 weeks.

The influence of different footprint preparation techniques on tissue regeneration in rotator cuff repair in an animal model

INTRODUCTION

Rotator cuff tears are common diseases of the upper extremity. There are no recommendations to the surgeon on how to prepare the footprint to ensure optimal tendon-to-bone healing. However, biologic augmentation using stem cells and growth factors is considered to encourage the healing process of the tendon. The aim of the study was to investigate the biomechanical and histological outcome of different footprint preparations in rotator cuff repair.

MATERIAL AND METHODS

One hundred and eighty-nine Sprague-Dawley rats were randomly assigned to either spongialization, radiofrequency ablation or an untreated control group. Rats were killed after 1 or 7 weeks for histological evaluation or after 7 weeks for biomechanical testing.

RESULTS

Histological evaluation showed better tissue organization in the control and spongialization group compared to the radiofrequency ablation group. The highest collagen I to collagen III quotient was found in the control group, followed closely by the spongialization group. Measured quotients showed a decrease in the values after 1 week compared to the values after 7 weeks, except in the radiofrequency ablation group, where an increase was detected. A significant difference was found in the load to failure test comparing the radiofrequency ablation group to the spongialization group (p = 0.0409) and control group (p = 0.014), but not comparing the spongialization group to the control group (p = 0.2456).

CONCLUSIONS

The results of this study suggest that spongialization of the footprint before attaching the torn supraspinatus tendon can lead to better structural properties and higher quality of tendon-to-bone restoration at the insertion area when compared with radiofrequency ablation.

Platelet-rich plasma supplementation in arthroscopic repair of full-thickness rotator cuff tears: a randomized clinical trial

BACKGROUND

Results on the effectiveness of PRP supplementation in arthroscopic rotator cuff repair are conflicting, making it difficult to draw definitive conclusions.

METHODS

This was a prospective, randomized, and double-blind study with two groups of 20 patients each (PRP group and control group). Degenerative supraspinatus full-thickness tears grade C2-C3 were subjected to arthroscopic repair; PRP supplementation was given to patients in the PRP group. The outcomes were assessed by DASH, Constant scales, and ultrasound before and 6 months after surgery. Pain measured by VAS was evaluated preoperatively and 7 and 30 days after surgery.

RESULTS

The two groups did not differ significantly by age, sex, and dominance of the affected side. In all surgical procedures, a long head of the biceps tenotomy and single-row repair were performed. The preoperative VAS was 5.6 ± 2.4 in PRP group and 6.4 ± 1.5 in the control group (p > 0.05). The group supplemented with PRP reported a VAS significantly better in the first week (2.5 ± 1.9 vs 5.3 ± 2.1, p < 0.05) and during the first month after surgery (1.5 ± 1.0 vs 3.2 ± 1.7, p < 0.05) compared to the control group. The preoperative Constant and DASH scores were 39.95 ± 12 and 51 ± 15.2, respectively, in the PRP group and 41 ± 11 (p > 0.05) and 45 ± 12.6 (p > 0.05) in the control group. The average Constant score improved significantly after 6 months to 81 ± 11.2 (p < 0.05) in the PRP group and 78.5 ± 9 (p < 0.05) in the control group. No differences were noted between the two groups (p > 0.05). The DASH score after 6 months was 17.4 ± 8 (p < 0.05) for the treatment group (the PRP group) and 21 ± 8.4 (p < 0.05) for the control group. No statistically significant differences were found as regards the DASH score in the two groups after 6 months (p > 0.05). The two groups showed no differences in the ultrasound evaluation after 6 months either. No re-ruptures occurred in either group.

CONCLUSIONS

PRP leads to a reduction in pain during a short-term follow-up. Pain reduction allows for a more rapid recovery of mobilization and improvement in functionality.

LEVEL OF EVIDENCE

Randomized controlled trial, Level of evidence, 1.