The effectiveness of intravenous zoledronic acid in elderly patients with osteoporosis after rotator cuff repair: a retrospective study.

The aim of this study was to investigate the effect of zoledronic acid (ZA) on postoperative healing and functional rehabilitation in osteoporotic patients with rotator cuff (RC) injury. 96 Patients were divided into three groups according to bone mineral density and ZA use (Group A: normal BMD; Group B: osteoporosis and intravenous ZA use; Group C: osteoporosis, without ZA use). Radiologic, functional and Serological outcomes were evaluated 6 months after surgery. The functional scores in all groups exhibited significant improvement 6 months after surgery. Inter-group comparison showed that Constant Shoulder joint function Score (CSS) of group A not significantly differing from that of group B, the other indicators were significantly better than those of group B and C. There were no significant differences in shoulder forward flexion, abductive Range of Motion between group B and C. Other indicators of group B were significantly improved compared to group C. The retear rate in group C (30.3%, 10/33) was higher than group A (6.1%, 2/33) and group B (13.3%, 4/30). In conclusion, the application of ZA can significantly reduce the rate of RC retear in elderly patients with osteoporosis after surgery, which is significant for postoperative shoulder joint functional rehabilitation.

Effect of polydeoxyribonucleotide and polynucleotide on rotator cuff healing and fatty infiltration in a diabetic rat model.

Failure rate after chronic rotator cuff repair is considerably high. Moreover, diabetes mellitus is known as a compromising factor of rotator cuff tear. The effect of Polydeoxyribonucleotide (PDRN) and polynucleotide (PN) on tendon healing and fatty infiltration is unclear as tissue regeneration activator in diabetic state. Therefore, a diabetic rat model with chronic rotator cuff tear was made for mechanical, histologic and blood tests. In the animal study using a diabetic rat cuff repair model, the administration of PDRN and PN increased the load to failure of repaired cuffs and improved tendon healing and decreased fatty infiltration. Also, the plasma levels of vascular endothelial growth factor and fibroblast growth factor were elevated in PDRN and PN administrated groups. We concluded that PDRN and PN appear to boost tendon recovery and reduce the presence of fatty infiltration following cuff repair in diabetic state. Also, PN showed a later onset and a longer duration than PDRN associated with the mean plasma growth factors.

Biomechanical and histological evaluation of aspirin in rotator cuff tear rat model.

Background: Aspirin is a representative non-steroidal anti-inflammatory drug (NSAIDs) and has been commonly used for the treatment of tendinopathy in clinical practice. In this study, we aimed to evaluate the biomechanical and histological healing effects of aspirin on the healing of the tendon-to-bone interface after rotator cuff tear repair. Methods: A total of 20 male Sprague-Dawley rats were randomly divided into two groups of 10 rats each. Group-C performed repaironly, and group-aspirin treated with aspirin after tendon repair. Group-aspirin rat were intraperitoneally injected with aspirin at 10 mg/kg every 24 h for 7 days. Eight weeks after surgery, the left shoulder of each rat was used for histological analysis and the right shoulder for biomechanical analysis. Results: In the biomechanical analysis, there was no significant difference in load-to-failure (group-C: 0.61 ± 0.32 N, group-aspirin: 0.74 ± 0.91 N; p = .697) and ultimate stress (group-C: 0.05 ± 0.01 MPa, group-aspirin: 0.29 ± 0.43 MPa; p = .095). For the elongation (group-C: 222.62 ± 57.98%, group-aspirin: 194.75 ± 75.16%; p = .028), group-aspirin confirmed a lower elongation level than group-C. In the histological evaluation, the Bonar score confirmed significant differences in collagen fiber density (group-C: 1.60 ± 0.52, group-aspirin: 2.60 ± 0.52, p = .001) and vascularity (group-C: 1.00 ± 0.47, group-aspirin: 2.20 ± 0.63, p = .001) between the groups. Conclusions: Aspirin injection after rotator cuff tear repair may enhance the healing effect during the early remodeling phase of tendon healing.

Graded Modulation of Inflammation by Metal Ion-Coordinated Peptide-Based Hydrogel Chemical Regulators Promotes Tendon-Bone Junction Regeneration.

After rotator cuff injuries, uncontrolled inflammation hinders tendon-bone junction regeneration and induces scar formation in situ. Therefore, precisely controlling inflammation could be a solution to accelerate tendon-bone junction regeneration. In this study, we synthesized a peptide-metal ion complex hydrogel with thermosensitive capability that can be used as a hydrogel chemical regulator. By the coordination complex between Mg2+ and BMP-12, the free and coordinated Mg2+ can be programmability released from the hydrogel. The fast release of free Mg2+ can prevent inflammation at the early stage of injuries, according to the results of RT-qPCR and immunofluorescence staining. Then, the coordinated Mg2+ was slowly released from the hydrogel and provided an anti-inflammatory environment for tendon-bone junction regeneration in the long term. Finally, the hydrogel demonstrated enhanced therapeutic effects in a rat rotator cuff tear model. Overall, the Mg2+/BMP-12 peptide-metal ion complex-based hydrogel effectively addresses the regenerative requirements of the tendon-bone junction across various stages by graded modulating inflammation.

Comparative efficacy of platelet-rich plasma (PRP) injection versus PRP combined with vitamin C injection for partial-thickness rotator cuff tears: a randomized controlled trial.

BACKGROUND: The optimal approach for managing partial-thickness rotator cuff tears (PTRCT) remains controversial. Recent studies related to PTRCTs have shown that platelet-rich plasma (PRP) injection might be an effective treatment option. Despite the role of vitamin C in collagen synthesis and its antioxidant properties, the effects of combined PRP and vitamin C treatment on rotator cuff repair are not well understood. This study investigated the effect of combined treatment of PRP and vitamin C treatment on PTRCTs. METHODS: One hundred-ten patients with PTRCTs were randomly allocated to two groups and underwent subacromial injections of either (A) normal saline and platelet-rich plasma or (B) vitamin C and platelet-rich plasma. The Constant score, American Shoulder and Elbow Surgeons (ASES) score, and visual analog scale were used to evaluate the outcomes before, 1 month after, and 3 months after injection. RESULTS: At the 3-month follow-up, no statistically significant differences were observed between the two groups in terms of ASES and Constant scores. Although a slight difference favoring group B was noted in functional scores and pain reduction, this difference was not statistically significant. However, both groups demonstrated significant pain reduction over time (p-value < 0.001). Additionally, the enhancement of ASES and Constant scores in both groups was statistically significant (p-value < 0.001). CONCLUSIONS: In conclusion, both PRP injection alone and PRP combined with vitamin C led to significant reductions in pain and enhancements in function scores over time (p < 0.001), suggesting the effectiveness of PRP as a non-surgical treatment for PTRCTs within 3 months. While PRP alone showed significant benefits, further research is required to ascertain if the combination therapy offers statistically significant advantages over PRP alone. TRIAL REGISTRATION: Clinical trial registration code: IRCT20230821059205N1.

Effect of magnetic microbeads on sustained and targeted delivery of transforming growth factor-beta-1 for rotator cuff healing in a rat rotator cuff repair model.

Structural failure is a well-established complication of rotator cuff repair procedures. To evaluate the effect of magnetic microbeads, designed for precise drug delivery via magnetic force, on sustained transforming growth factor-beta-1 (TGF-ß1) release and rotator cuff healing in a rat rotator cuff repair model. TGF-ß1 laden microbeads were prepared, and baseline in vitro experiments included the magnetization of the microbeads and TGF-ß1 release tests. In an in vivo experiment using a rat rotator cuff repair model on both shoulders, 72 rats were randomly assigned to three groups (24 per group): group A, conventional repair; group B, repair with and simple TGF-ß1 injection; and group C, repair with magnet insertion into the humeral head and TGF-ß1 laden microbead injection. Delivery of TGF-ß1 was evaluated at 1 and 7 days after the intervention using PCR, Western blot, and immunohistochemistry. At 6 weeks post-intervention, rotator cuff healing was assessed using biomechanical and histological analysis. The in vitro experiments confirmed the magnetization property of the microbeads and sustained delivery of TGF-ß1 for up to 10 days. No difference in the TGF-ß1 expression was found at day 1 in vivo. However, at day 7, group C exhibited a significantly elevated expression of TGF-ß1 in both PCR and Western blot analyses compared to groups A and B (all P < 0.05). Immunohistochemical analysis revealed a higher expression of TGF-ß1 at the repair site in group C on day 7. At 6 weeks, biomechanical analysis demonstrated a significantly higher ultimate failure load in group C than in groups A and B (P < 0.05) and greater stiffness than in group A (P = 0.045). In addition, histological analysis showed denser and more regular collagen fibers with complete continuity to the bone in group C than in groups A and B, a statistically significant difference according to the semi-quantitative scoring system (all P < 0.05). The use of the TGF-ß1 laden magnetic microbeads demonstrated sustained delivery of TGF-ß1 to the repair site, improving rotator cuff healing.

Efficacy of hypertonic dextrose proliferation therapy in the treatment of rotator cuff lesions: a meta-analysis.

BACKGROUND: One of the most prevalent illnesses of the shoulder is rotator cuff tendinosis, which is also a major contributor to shoulder discomfort and shoulder joint dysfunction. According to statistics, rotator cuff tendinosis occurs in 0.3-5.5% of cases and affects 0.5-7.4% of people annually. It will be necessary to conduct a meta-analysis to evaluate the efficacy of hypertonic glucose proliferation therapy in the treatment of rotator cuff problems. METHODS: The databases Cochrane PubMed, Library, Web of Science and EMbase, are retrieved by the computer. Individuals with rotator cuff lesions in the intervention group were treated with hypertonic dextrose proliferation therapy, whereas individuals in the control condition were treated with a placebo. Outcome markers for rotator cuff lesions patients; Pursuant to studies, the visual analogue scale (VAS) score, the shoulder pain & disability index (SPADI), & other metrics are used to evaluate the effects of hypertonic dextrose proliferation treatment on individuals with rotator cuff diseases. After carefully evaluating the calibre of the literature, data analysis was performed utilising the RevMan 5.3 programme. RESULTS: Meta-analysis finally contained 6 papers. In six investigations, the test & control group's VAS scores improved, with the test team's score considerably outperforming the control team [standardized mean difference (SMD): 1.10; 95% Cl: 0.37,1.83; P < 0.01], shoulder pain and disability index (SPADI) score (SMD:8.13; 95% Cl: 5.34,10.91; P < 0.01), Flexion (SMD:5.73; 95% Cl: 0.99,10.47; P < 0.05), Abduction (SMD:6.49; 95% Cl: 0.66,12.31; P < 0.05), Internal rotation (SMD:-1.74; 95% Cl: -4.25,0.78; P = 0.176) and External rotation (SMD:2.78; 95% Cl: -0.13,5.69; P = 0.062). CONCLUSION: The findings of this study suggest that individuals with rotator cuff injuries may benefit from hypertonic dextrose proliferation treatment based on the visual analogue scale (VAS) score, the Shoulder Pain and Disability Index (SPADI) score, Flexion, & Abduction. These results must, nevertheless, be supported by high-caliber follow-up research.

Metformin mitigates adipogenesis of fibro-adipogenic progenitors after rotator cuff tears via activating mTOR/ULK1-mediated autophagy.

Muscular fatty infiltration is a common issue after rotator cuff tears (RCTs), which impair shoulder function. Females suffer a higher prevalence and a more severe degree of muscular fatty infiltration after RCT when compared with males, with the underlying mechanisms remaining unclear. Fibro-adipogenic progenitors (FAPs) are the primary source of muscular fatty infiltration following RCT. Our findings disclose that gender-specific disparities in muscular fatty infiltration are linked to mTOR/ULK1-mediated autophagy of FAPs. Decreased autophagic activity contributes to adipogenic differentiation in female FAPs after RCT. Furthermore, metformin could enhance mTOR/ULK1-mediated autophagic processes of FAPs, thereby alleviating fatty infiltration and improving shoulder functionality after RCT. Together, our study reveals that gender differences in muscular fatty infiltration arise from distinct autophagic activities. Metformin could be a promising noninvasive intervention to ameliorate muscular fatty infiltration of RCT.NEW & NOTEWORTHY The current study demonstrated that gender-specific disparities in muscular fatty infiltration are attributed to mTOR/ULK1-mediated autophagy of FAPs. Decreased autophagic activity contributes to adipogenic differentiation in female FAPs after RCT. Moreover, metformin could enhance mTOR/ULK1-mediated autophagic processes of FAPs, thereby alleviating fatty infiltration and improving shoulder functionality after RCT. Therefore, metformin could be a promising noninvasive intervention to ameliorate muscular fatty infiltration of RCT.

Editorial Commentary: Tranexamic Acid Shown to Not Inhibit Healing Following Rotator Cuff Repair in Rats.

As use of tranexamic acid (TXA) to decrease operative bleeding has increased during various orthopaedic surgical procedures, there has been corresponding increased interest regarding additional potential benefits-and also potential risks-of its use. By lessening bleeding during and shortly after arthroscopic surgery, some potential benefits include less postoperative pain, less hemarthrosis, and subsequent decreased formation of scar adhesions, resulting in less permanent stiffness. However, use of this pharmacologic agent also raises the possibility of negative effects upon tissue healing. In a rat rotator cuff repair model, no lasting significant benefit was associated with TXA administration, including no long-term decreased adhesions or stiffness. On the other hand, no adverse effects regarding healing were noted with TXA.

Research Progress of TCM Therapy for Rotator Cuff Injury.

BACKGROUND: Rotator cuff injury is a common orthopedic disease with high morbidity, which is one of the most important reasons for shoulder pain and limited movement. With the development of more research, the Traditional Chinese Medicine(TCM) therapy for rotator cuff injury is increasingly rich, and has achieved a good curative effect. METHOD: TCM has certain characteristics and advantages, which may become the main development trend of the treatment. By consulting the relevant literature on TCM therapy for rotator cuff injury in recent years, we found that commonly used TCM therapy include Chinese herbal therapy, Chinese herbal compounds. RESULT: External treatment of Chinese herbal therapy, Acupuncture therapy, Floating needle therapy, Massage therapy, and others, which make a great clinical effect. CONCLUSION: This paper summarizes and analyzes the common TCM therapy of the rotator cuff injury, to provide new ideas for the selection of clinical treatment options.

Tranexamic Acid Can Reduce Early Tendon Adhesions After Rotator Cuff Repair and Is Not Detrimental to Tendon-Bone Healing: A Comparative Animal Model Study.

PURPOSE: To determine the effects of topical tranexamic acid (TXA) administration on tendon adhesions, shoulder range of motion (ROM), and tendon healing in an acute rotator cuff repair rat model. METHODS: A total of 20 Sprague Dawley rats were used. Tendon adhesion, ROM, and biomechanical and histological analysis of tendon-bone healing was conducted at 3 and 6 weeks after surgery. The rats underwent rotator cuff repair surgery on both shoulders and were administered TXA via subacromial injections. The tendon adhesion was evaluated macroscopically and histologically. Biomechanical tendon healing was measured using a universal testing machine, and histological analysis was quantified by H&E, Masson's trichrome, and picrosirius red staining. RESULTS: At 3 weeks after surgery, the adhesion score was significantly lower in the TXA group (2.10 ± 0.32) than in the control group (2.70 ± 0.48) (P = .005), but there was no significant difference between the 2 groups at 6 weeks. Regarding ROM, compared with the control group, the TXA group showed significantly higher external rotation (36.35° ± 4.52° vs 28.42° ± 4.66°, P < .001) and internal rotation (45.35° ± 9.36° vs 38.94° ± 5.23°, P = .013) 3 weeks after surgery. However, at 6 weeks, there were no significant differences in external and internal rotation between the 2 groups. In the biomechanical analysis, no significant differences in gross examination (3 weeks, P = .175, 6 weeks, P = .295), load to failure (3 weeks, P = .117, 6 weeks, P = .295), or ultimate stress (3 weeks, P = .602, 6 weeks, P = .917) were noted between the 2 groups 3 and 6 weeks after surgery. In the histological analysis of tendon healing, no significant differences in the total score (3 weeks, P = .323, 6 weeks, P = .572) were found between the 2 groups 3 and 6 weeks after surgery. CONCLUSIONS: Topical TXA administration showed a beneficial effect in reducing tendon adhesions and improving ROM 3 weeks postoperatively and had no effect at 6 weeks. This suggests that additional intervention with TXA may be useful in achieving long-term improvement in shoulder stiffness. Additionally, TXA may increase tissue ground substance accumulation in the late postoperative period but does not adversely affect tendon-bone interface healing. CLINICAL RELEVANCE: The use of TXA after rotator cuff repair has no effect on tendon-bone interface healing in clinical practice and can improve shoulder stiffness in the early postoperative period. Additional research on the long-term effects is needed.

Risk of rotator cuff tear and rotator cuff repair surgery comparison between sodium-glucose cotransporter 2 inhibitors and glucagon like peptide-1 receptor agonists: A real-world study.

AIM: Theoretically, sodium-glucose cotransporter 2 inhibitors (SGLT2is) reduce the risk of rotator cuff tear through an anti-inflammatory mechanism. To clarify this association, in this study, we compared SGLT2is users and glucagon-like peptide-1 receptor agonists (GLP-1RAs) users in terms of the risk of rotator cuff tear and the risk of receiving rotator cuff repair surgery. METHODS: A retrospective cohort analysis was conducted using data from the TriNetX platform. A target trial design was adopted to identify patients with type 2 diabetes mellitus who started receiving SGLT2is or GLP-1RAs. Propensity score matching was used to form two homogeneous groups. The study outcomes were the risk of rotator cuff tear and the risk of receiving rotator cuff repair surgery. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were calculated within the TriNetX platform. RESULTS: Initially, 351,800 SGLT2is users and 387,616 GLP-1RAs users were identified. After propensity score matching, each group comprised 274,026 patients. The mean age was 59.5 years in both groups; the proportions of women in the SGLT2is and GLP-1RAs groups were 46.9 % and 46.7 %, respectively. Compared with the GLP-1RAs group, the SGLT2is group had significantly reduced risks of rotator cuff tear (HR 0.812 [0.761;0.867]) and rotator cuff repair surgery (HR 0.900 [0.815;0.994]). CONCLUSION: SGLT2is appear to reduce the risk of rotator cuff tear and the risk of receiving rotator cuff repair surgery in patients with type 2 diabetes mellitus. Further prospective studies are needed to validate our findings.

Portal-site epinephrine injections improve visualisation in arthroscopic rotator cuff repair.

OBJECTIVES: The aim of this study was to evaluate if portal-site injections of 1:200,000 epinephrine improve intraoperative visualisation in arthroscopic rotator cuff repair. METHODS: Patients with partial-thickness supraspinatus tears were selected for the study. They were assigned consecutive numbers and were divided into two groups-control group and intervention group. The surgeries were done by a single surgeon. Every odd-numbered patient was injected. Johnson's visibility classification, surgeon 5-point ordinal Likert scale (LS), and other parameters were recorded. RESULTS: A total of 221 participants (58.4 â€‹± â€‹6.1 years) were selected. Intraoperative visibility was better in the intervention group according to Johnson's classification-satisfactory visibility was achieved in 68 of 110 patients (62%, control group) compared to 89 of 111 patients (80%) (p â€‹= â€‹0.003). Surgeon LS was superior in the intervention group, with a notable decrease in worsened visibility cases. The operative time did not alter statistically significantly-82.2 â€‹± â€‹14.4 â€‹min for the control group, compared to 80.9 â€‹± â€‹10.8 â€‹min in the intervention group (p â€‹= â€‹0.056). No injection-associated complications were recorded. CONCLUSIONS: Portal-site injection of diluted epinephrine solution is safe and improves intraoperative visualisation in arthroscopic rotator cuff repair. This addition does not increase operative time. LEVEL OF EVIDENCE: Level 3, case-control study.

Editorial Commentary: Biocomposite Implant Combined With Local Human Recombinant Parathyroid Hormone Enhances the Histological Quality and Biomechanical Strength of Rotator Cuff Repairs.

Rates of rotator cuff repair retear remain unacceptably high and are frequently the source of diminished shoulder function and patient dissatisfaction. Endocrinopathies have been implicated in these processes. Parathyroid hormone (PTH) activates chondrogenesis and angiogenesis at the enthesis and prevents fatty infiltration and atrophy in rotator cuff musculature. These facts have spurred interest in the therapeutic benefits of PTH as a means to enhance tendon healing and strengthen the bone in and around tendon repairs. New research demonstrates that recombinant human PTH delivered locally through a process of coupling it to a bioengineered scaffold "sheath" may be beneficial. The growth factor, encased within polycaprolactone (PCL), is slowly released as the PCL degrades to extend drug delivery time. The augmentation of rotator cuff repairs with this biocomposite material improves short-term structural tissue integrity and promotes the formation of more organized and stronger tendon-to-bone interface in a rabbit model.

Editorial Commentary: Postoperative Zoledronic Acid Improves Tendon Healing but Does Not Affect Outcomes in Rotator Cuff Repair Patients With Postmenopausal Osteoporosis.

Understanding the preoperative risk factors for successful rotator cuff repair (RCR) and ways to optimize these factors is an evolving area of study. The Rotator Cuff Healing Index and other proxy risk factors for failed rotator cuff healing have implicated significant fatty infiltration, muscular atrophy, advanced chronological age, tear size and retraction, and ultimately, osteoporosis. Although structural (or biological) augmentation and tendon transfer have been proposed as solutions for the alarmingly high rate of failure after primary RCR, other options may preferentially focus on the enthesis and underlying osseous footprint. Currently, bisphosphonates are frequently used in the treatment of osteoporosis and prevention of fragility fractures. However, burgeoning evidence suggests that postoperative zoledronic acid may have clinical utility after rotator cuff and other tendon repairs. In the cost-conscious world of evidence-based medicine, the added economic burden of additional medications and office visits may or may not improve patient outcomes-much less confer added value. Our advice to fellow shoulder surgeons: Wait for further information, but continue to holistically consider and optimize risk factors for poor soft-tissue healing. Although the addition of postoperative bisphosphonates may improve suture anchor fixation and promote a better foundation for healing, it will not immediately transform your RCR success rates.

Editorial Commentary: Corticosteroid Injections Administered Within 4 Weeks Before Shoulder Arthroscopy Are Associated With an Increased Risk of Infection.

Corticosteroid injections are a frequently used modality for addressing shoulder pain. The widespread utilization of corticosteroid injections is supported by clinical practice guidelines and consensus statements including the 2019 American Academy for Orthopaedic Surgeons (AAOS) guidelines for the management of rotator cuff injuries. However, steroids may be detrimental to healing potential following cuff repair and increase the risk of re-tear. In addition, corticosteroid injections administered within 4 weeks prior to shoulder arthroscopy are associated with an increased risk of infection. The degree of risk is dependent on the timing of surgery with longer time intervals between injection and shoulder arthroscopy being associated with less risk. The next version of the AAOS clinical practice guidelines for managing rotator cuff tears should incorporate commentary on the specific risk of surgical site infection following pre-operative corticosteroid injections, as well as on the timing of injections, with the aim of increasing awareness of these potentially devastating adverse effects.

Effect of tetrahedral framework nucleic acids on the reconstruction of tendon-to-bone injuries after rotator cuff tears.

Clinicians and researchers have always faced challenges in performing surgery for rotator cuff tears (RCT) due to the intricate nature of the tendon-bone gradient and the limited long-term effectiveness. At the same time, the occurrence of an inflammatory microenvironment further aggravates tissue damage, which has a negative impact on the regeneration process of mesenchymal stem cells (MSCs) and eventually leads to the production of scar tissue. Tetrahedral framework nucleic acids (tFNAs), novel nanomaterials, have shown great potential in biomedicine due to their strong biocompatibility, excellent cellular internalisation ability, and unparalleled programmability. The objective of this research was to examine if tFNAs have a positive effect on regeneration after RCTs. Experiments conducted in a controlled environment demonstrated that tFNAs hindered the assembly of inflammasomes in macrophages, resulting in a decrease in the release of inflammatory factors. Next, tFNAs were shown to exert a protective effect on the osteogenic and chondrogenic differentiation of bone marrow MSCs under inflammatory conditions. The in vitro results also demonstrated the regulatory effect of tFNAs on tendon-related protein expression levels in tenocytes after inflammatory stimulation. Finally, intra-articular injection of tFNAs into a rat RCT model showed that tFNAs improved tendon-to-bone healing, suggesting that tFNAs may be promising tendon-to-bone protective agents for the treatment of RCTs.

Dual Growth Factor Delivery Using Photo-Cross-Linkable Gelatin Hydrogels for Effectively Reinforced Regeneration of the Rotator Cuff Tendon.

Rotator cuff tears are currently treated with drugs (steroids and nonsteroidal anti-inflammatory drugs) and surgery. However, the damaged rotator cuff requires a considerable amount of time to regenerate, and the regenerated tissue cannot restore the same level of function as that before the damage. Although growth factors can accelerate regeneration, they are difficult to be used alone because of the risk of degradation and the difficulties in ensuring their sustained release. Thus, hydrogels such as gelatin are used, together with growth factors. Gelatin is a biocompatible and biodegradable hydrogel derived from collagen; therefore, it closely resembles the components of native tissues and can retain water and release drugs continuously, while also showing easily tunable mechanical properties by simple modifications. Moreover, gelatin is a natural biopolymer that possesses the ability to form hydrogels of varying compositions, thereby facilitating effective cross-linking. Therefore, gelatin can be considered to be suitable for rotator-to-tendon healing. In this study, we designed photo-cross-linkable gelatin hydrogels to enhance spacing and adhesive effects for rotator cuff repair. We mixed a ruthenium complex (Ru(II)bpy32+) and sodium persulfate into gelatin-based hydrogels and exposed them to blue light to induce gelation. Basic fibroblast growth factor and bone morphogenetic protein-12 were encapsulated in the gelatin hydrogel for localized and sustained release into the wound, thereby enhancing the cell proliferation. The effects of these dual growth factor-loaded hydrogels on cell cytotoxicity and tendon regeneration in rotator cuff tear models were evaluated using mechanical and histological assessments. The findings confirmed that the gelatin hydrogel was biocompatible and that treatment with the dual growth factor-loaded hydrogels in in vivo rotator cuff tear models promoted regeneration and functional restoration in comparison with the findings in the nontreated group. Therefore, growth factor-loaded gelatin-based hydrogels may be suitable for the treatment of rotator cuff tears.

Postoperative Antiosteoporotic Treatment with Zoledronic Acid Improves Rotator Cuff Healing but Does Not Improve Outcomes in Female Patients with Postmenopausal Osteoporosis: A Prospective, Single-Blinded, Randomized Study.

PURPOSE: To investigate the effect of the antiosteoporotic agent zoledronic acid (ZA) on rotator cuff healing and clinical outcomes in patients with postmenopausal osteoporosis. METHODS: We prospectively enrolled 138 female patients with postmenopausal osteoporosis who were scheduled to undergo arthroscopic rotator cuff repair (ARCR) from March 2020 to March 2021. Patients were randomly allocated to the ZA group (ARCR followed by intravenous ZA infusions at postoperative Day 1 and 1 year later) and the control group (ARCR alone). All patients were followed up for 24 months. Tendon healing was evaluated by ultrasonography at 6 weeks and 24 months after surgery. The American Shoulder and Elbow Surgeons (ASES) score, Western Ontario Rotator Cuff (WORC) index, and Numeric Rating Scale (NRS) for pain were recorded at each follow-up, and the minimal clinically important difference (MCID) was calculated. RESULTS: A total of 124 patients were included in the final analysis, 61 in the ZA group and 63 in the control group. There was no statistically significant difference in participant characteristics between the 2 groups. The ZA group had a significantly higher tendon healing rate than the control group at 2 years after surgery (odds ratio = 5.0; 95% confidence interval [CI], 1.4-18.7; P = .014). Regarding clinical outcomes, 100% of patients exceeded the MCID in both groups, and no significant differences were found at 2 years after surgery between the 2 groups (ASES: 2.5 [95% CI, -2.2 to 7.2; P = .291]; WORC index: 4.5 [95% CI, -0.117 to 9.117; P = .056]; NRS: -0.1 [95% CI, -0.3 to 0.1; P = .394]). CONCLUSIONS: Antiosteoporotic treatment with ZA reduced the retear rate but did not significantly influence the clinical outcomes after ARCR in female patients with postmenopausal osteoporosis. Outcomes of ARCR showed good results in both groups and exceeded the MCID. LEVEL OF EVIDENCE: Level I, randomized controlled trial.

Estrogen and testosterone supplementation improves tendon healing and functional recovery after rotator cuff repair.

Failure of healing after rotator cuff repair (RCR) is common. The purpose of the current study was to evaluate the effect of systemic estrogen or testosterone supplementation on tendon healing after RCR. Seventy-two adult male mice were utilized for all experiments. The supraspinatus tendon was transected and repaired with 6-0 Prolene suture on the left shoulder of 51 animals. Mice were segregated into three groups postoperative: (1) vehicle group (VG; n = 18), (2) estrogen group (EST; n = 17), and (3) testosterone group (TST; n = 16). An unrepaired control group (unrepaired, n = 21) did not have surgery. Utilizing these animals, histological analysis, activity testing, biomechanical testing and RNA sequencing (RNA-seq) was performed. At 8 weeks post-RCR, TST, and EST supplementation improved the overall histologic structure of the repaired enthesis site. No differences in ultimate failure loads or stiffness were detected between VG, EST, and TST groups after biomechanical testing. RCR caused a reduction in wheel activity compared to unrepaired controls and supplementation with TST restored wheel activity. RNA-seq analysis indicated that estrogen and testosterone regulated different pathways associated with enthesis healing, including a suppression of inflammatory signaling. Supplementation with sex hormones improved the structure of the repaired tendon enthesis and significantly regulated expression of diverse pathways regulating multiple biological processes. Testosterone administration following RCR restored wheel activity without having a detrimental impact on biomechanical strength. Future human studies of sex hormone supplementation after RCR are warranted as supplementation in an animal model may improve tendon enthesis healing.