A Combination Treatment of Raloxifene and Vitamin D Enhances Bone-to-Tendon Healing of the Rotator Cuff in a Rat Model

The effect of applying anti-osteoporosis drugs on the rehabilitation of patients with rotator cuff tears after arthroscopic rotator cuff repair: a meta-analysis

BACKGROUND

This comprehensive meta-analysis aimed to elucidate the effects of anti-osteoporosis (OP) drugs in patients who experienced rotator cuff tears and underwent arthroscopic repair.

METHODS

The PubMed, Embase, Web of Science, and Cochrane Central databases were searched to identify studies that examined the effects of anti-OP drugs among patients with rotator cuff tears who underwent arthroscopic rotator cuff repair. Specifically, studies that evaluated the retear rate and other subjective or objective outcomes were included in the analysis. The databases were searched from inception to January 13, 2025.

RESULTS

Ultimately, 5 articles were included in this meta-analysis. Compared with the control group, the anti-OP drug group had a lower retear rate, higher American Shoulder and Elbow Surgeon scores and a greater internal rotation angle. The Simple Shoulder Test, University of California, Los Angeles shoulder score, Constant Shoulder score, and forward flexion angle were not markedly different between the two groups.

CONCLUSION

Anti-OP drugs markedly promoted bone-to-tendon healing and improved quality of life among patients who underwent arthroscopic rotator cuff repair, especially with respect to activities that involve internal rotation of the shoulder.

Non-thermal atmospheric pressure gas discharge plasma enhances tendon-to-bone junction repair in a rabbit model

BACKGROUND

Plasma is a collection of active particles generated by dissociating molecules and ionizing atoms through applying high energy to a gas, such as high-sound heating or electrical shock. Recently, many reports have been published on the effectiveness of non-thermal atmospheric pressure gas discharge plasma (NTAPP) on living organisms. Furthermore, we have reported on the promotion of bone and tendon repair by NTAPP irradiation. We hypothesized that irradiation of NTAPP would promote the repair of the tendon-bone junction in a rotator cuff repair. This study investigated the effect of NTAPP irradiation on the healing process of the tendon-bone junction.

METHODS

Among 36 Japanese white rabbits, the infraspinatus tendon was detached from the humeral insertion site. A 3.2 mm bone tunnel was then created at the original insertion site of the infraspinatus muscle. The left shoulder was irradiated with NTAPP at a distance of 1 cm from the bone tunnel for 5 minutes (plasma-treated group), while the right shoulder was not irradiated (control group). The rabbits were sacrificed at 2, 4, and 8 weeks postoperatively, and 6 of each were used for histological evaluation. Mechanical tests were also performed on 6 specimens each at 4 and 8 weeks.

RESULTS

Histological evaluation showed that at 4 weeks, the histological tendon to bone maturing score was 6.8 ± 1.3 in the plasma-treated group and 4.8 ± 1.6 in the control group (P < .01); at 8 weeks it was 9.0 ± 1.0 in the plasma-treated group and 5.2 ± 1.1 in the control group (P < .01). Fibrocartilage formation and new bone formation were observed at both 4 and 8 weeks. In the mechanical test, the plasma-treated group had 75.0 ± 18.9 N in ultimate load to failure at 8 weeks. In the control group, it was 51.1 ± 7.9 N. (P = .04).

CONCLUSION

The repair of the rotator cuff at the tendon-bone junction was significantly improved at 4 and 8 weeks by irradiation with NTAPP.

Leptin Enhances M1 Macrophage Polarization and Impairs Tendon-Bone Healing in Rotator Cuff Repair: A Rat Model

BACKGROUND

Rotator cuff tears are common, affecting more than 60% of individuals older than 80 years, and they have been implicated in 70% of patients with shoulder pain. M1 polarization-related inflammation has been reported to be associated with poor healing outcomes of rotator cuff injury, and leptin, an adipokine, has been reported to be a potential activator of inflammation. However, whether leptin affects rotator cuff repair remains unknown.

QUESTIONS/PURPOSES

Using in vitro cell experiments and an in vivo rat rotator cuff tear model, we therefore asked: (1) Does leptin promote the M1 polarization of macrophages in vitro and in vivo? (2) Does leptin impair biomechanical strength, the histologic structure of the tendon-bone interface, bone mineral density (BMD), or gait in the rotator cuff tear scenario? (3) Does leptin promote M1 polarization by upregulating the tumor necrosis factor (TNF) pathway?

METHODS

The impact of leptin on M1 macrophage polarization in vitro was determined by reverse transcription-polymerase chain reaction (RT-PCR), the Western blot test, and immunofluorescence staining. The effect of leptin on tendon-bone healing was assessed in an in vivo rat rotator cuff tear model by comparing a leptin group with a suture group in terms of gait, biomechanical tensile strength, the histologic structure of the tendon-bone interface, and BMD. In the in vivo experiments, 8-week-old male Sprague Dawley rats were used, adapting a previously developed rat rotator cuff tear model. The supraspinatus tendon was resected from the greater tuberosity bilaterally, and then the tendon was secured to its anatomical footprint using the transosseous single-row technique. In total, 30 rats were randomized into two groups (suture, leptin) by drawing lots (15 rats in each group). They were assessed at 2, 4, and 8 weeks after the surgery. In the suture group, 100 µL of normal saline was injected into the subacromial space after the deltoid muscle was restitched to the original position. In the leptin group, 100 µL of leptin solution (200 ng/mL) was injected into the subacromial space after the deltoid muscle was restitched to the original position. Biomechanical properties including maximal failure load, stiffness, and tensile failure stress were determined to assess the biomechanical strength at 4 and 8 weeks after the surgery. Histologic staining was conducted to compare the structure of the tendon-bone interface between treatment groups. Micro-MRI and micro-CT assessments were conducted to compare the overall healing outcome and BMD between treatment groups. Gait analysis was conducted to compare the stride length and strength between treatment groups. M1 macrophage polarization in vivo at the tendon-bone interface was assessed by immunofluorescence staining. Finally, to explore the underlying mechanism of the effects of leptin, Necrostatin-1 (Nec-1) was used to block the TNF signaling pathway in the in vitro macrophage study, and RT-PCR and Western blot were used to explore the underlying mechanism.

RESULTS

Leptin enhanced LPS-induced M1 polarization of macrophages in vitro, showing increased gene expression of CD86, Nos2, and TNF-α as well as increased protein expression of CD86, TNF-α, interleukin-6 (IL-6), and inducible NO synthase (iNOS). The in vivo polarization showed that the M1 polarization of macrophages at the tendon-bone interface was promoted. At 2 weeks postoperatively, there were more M1 cells in the leptin group (53 ± 5 versus 77 ± 8, mean difference 24 [95% confidence interval (CI) 11 to 37]; p = 0.002), although the proportion of M1 cells (ratio of the number of M1 cells to the total number of macrophages) was not higher (18.6% ± 2.9% versus 21.5% ± 1.7%, mean difference 2.9% [95% CI -2.8% to 8.7%]; p = 0.36). At 4 weeks postoperatively, the leptin group exhibited more M1 cells (31 ± 4 versus 50 ± 6, mean difference 19 [95% CI 6 to 32]; p = 0.008) and at a higher proportion (16.4% ± 2.6% versus 23.0% ± 3.0%, mean difference 6.6% [95% CI 0.8% to 12.4%]; p = 0.03). The in vivo experiments showed that leptin impaired tendon-bone healing. At 4 weeks postoperatively, the biomechanical properties of both groups were not different in terms of maximal failure load (12.7 ± 1.6 N versus 12.4 ± 1.8 N, mean difference -0.3 N [95% CI -2.6 to 1.8]; p = 0.91), stiffness (5.1 ± 0.7 N/mm versus 4.6 ± 0.8 N/mm, mean difference -0.5 N/mm [95% CI -1.3 to 0.5]; p = 0.44), and tensile failure stress (2.0 ± 0.3 N/mm2 versus 2.0 ± 0.3 N/mm2, mean difference 0.0 N/mm2 [95% CI -0.4 to 0.4]; p = 0.99). At 8 weeks postoperatively, the leptin group showed worse maximal failure load (17.6 ± 1.4 N versus 14.1 ± 1.4 N, mean difference -3.5 N [95% CI -5.7 to -1.3]; p = 0.002), stiffness (7.0 ± 0.6 N/mm versus 5.2 ± 0.6 N/mm, mean difference -1.8 N/mm [95% CI -2.7 to -0.9]; p < 0.001), and tensile failure stress (3.4 ± 0.3 N/mm2 versus 2.8 ± 0.4 N/mm2, mean difference -0.6 N/mm2 [95% CI -1.0 to -0.2]; p = 0.007). Results of histologic staining, image assessments, and gait analysis also demonstrated that leptin impaired the healing process. In vitro experiments showed that leptin upregulated the gene expression of molecules in the TNF pathway, including CCL2 and receptor-interacting protein kinase 1 (RIPK1), and M1 markers, such as TNF-α, CD86, and Nos2; the addition of Nec-1 neutralized the effect of leptin on macrophage polarization, reducing the expression of M1 markers, including TNF-α, CD86, and Nos2, and blocking the TNF signaling pathway, including CCL2 and RIPK. The protein expression exhibited similar trends.

CONCLUSION

Based on the results of this study, leptin appears to impair tendon-bone healing in a rat model of rotator cuff tear, promote M1 macrophage polarization at the tendon-bone interface, and upregulate the TNF signaling pathway in macrophages to promote M1 polarization.

CLINICAL RELEVANCE

Obesity and fatty infiltration of the rotator cuff muscle are associated with poor healing of rotator cuff tears. In this study, the effect of leptin, an adipose factor, on tendon-bone healing and the underlying mechanism were explored. Future studies might focus on developing novel approaches to improve the tendon-bone healing in patients with obesity by targeting leptin or the TNF signaling pathway with the aid of biomaterials.

Growth Hormone-Releasing Peptide 2 May Be Associated With Decreased M1 Macrophage Production and Increased Histologic and Biomechanical Tendon-Bone Healing Properties in a Rat Rotator Cuff Tear Model

PURPOSE

To explore the potential of growth hormone-releasing peptide 2 (GHRP-2) for tendon-bone healing in a rat rotator cuff tear (RCT) model.

METHODS

The impact of GHRP-2 on M1 macrophage polarization in vitro was determined using real-time polymerase chain reaction, Western blot, and immunofluorescence staining. GHRP-2 was then applied in a rat RCT model, and the healing of the tendon-bone interface was systemically evaluated by histologic staining, radiologic assessments, gait analysis, and biomechanical tests. M1 macrophage polarization at the tendon-bone interface was assessed by immunofluorescence staining.

RESULTS

GHRP-2 was found to reduce the expression of Cd86, Nos2, and tnfa (all P < .01), suggesting inhibited M1 macrophage polarization in vitro. The in vivo experiments showed that the proportion of M1 macrophages was reduced both 2 and 4 weeks after surgery (P < .01), and the number of M1 was reduced 4 weeks after surgery (P < .01) at the tendon-bone interface. The in vivo experiments also showed that histologic scores and bone mineral density were increased by GHRP-2 at 8 weeks postsurgery (P < .01), suggesting improved healing of the tendon-bone interface. Furthermore, the GHRP-2 group showed a better biomechanical property at both 4 and 8 weeks postsurgery, including maximal failure load, stiffness, and tension (all P < .01), and better gait parameters at 8 weeks postsurgery, including mean area of the left front foot and mean intensity of the right front foot (all P < .05).

CONCLUSIONS

GHRP-2 may be associated with decreased M1 macrophage production and increased histologic and biomechanical tendon-bone healing properties in a rat RCT model.

CLINICAL RELEVANCE

The present study might be a transitional study to show the efficacy of GHRP-2 in enhancing bone-tendon healing and reduce retear rate after rotator cuff repair.

Osteoporosis Management for Shoulder Surgeons

PURPOSE OF REVIEW

The aim of this review is to aggregate currently available literature as it pertains to treating surgical shoulder pathology in patients with osteoporosis.

RECENT FINDINGS

Emerging data surrounding perioperative use of anti-osteoporosis medications for patients undergoing shoulder surgery have not shown definitively favorable or unfavorable outcomes. Similar evaluations in animal studies have shown promising results as a biologic augment to tendon and bone healing, especially with newer, anabolic agents. The mainstay of bone health management remains pre-operative evaluation, using opportunistic radiographic and CT based validated measurements, along with optimization of risk factors. Surgical techniques continue to incorporate implants that perform well in osteopenic bone. Promising pre-clinical studies have identified anabolic anti-osteoporosis medications as viable biologic augments to shoulder surgery, which has not been borne out in any clinical studies at this time.

3D-printed biomimetic scaffolds loaded with ADSCs and BMP-2 for enhanced rotator cuff repair

Rotator cuff tear repair poses significant challenges due to the complex gradient interface structure. In the face of disease-related disruptions in the tendon-bone interface (TBI), the strategy of constructing a biomimetic scaffold is a promising avenue. A novel 3D-printed rotator cuff scaffold loaded adipose stem cells (ADSCs), bone morphogenetic protein-2 (BMP-2), and collagen type I (COL I). The efficiency of the slow-release BMP-2 design depended on the dopamine-hyaluronic acid (HAD) and BMP-2 reaction. The cumulative release of BMP-2 was 44.97 ± 5.45% at 4 weeks. The 3D-printed bilayer scaffold, incorporating COL I and BMP-2, effectively promoted the differentiation of ADSCs into osteogenic, tenogenic, and chondrogenic lineages in vitro. The combination of 3D-printed bioactive scaffolds and ADSCs demonstrated a superior repair effect on rotator cuff injuries in vivo. Therefore, these findings indicates that the 3D-printed biomimetic scaffold loaded with ADSCs and BMP-2 holds potential as a promising graft for TBI healing.

Osteoporosis in the setting of rotator cuff repair: A narrative review

Osteoporosis and osteopenia are frequently found in patients undergoing shoulder surgery, especially rotator cuff repair, and it is anticipated that this link will become more common as more elderly people have operations on their shoulders. For orthopedic surgical candidates who are at high risk, preoperative screening may identify those who might benefit from early intervention and prevent any associated adverse events. The major complications include repair failure and revision surgery. Antiresorptive medication preoperatively has shown good results in vivo. However, when used in the clinical setting, the efficacy remains controversial. Surgical management may include repair augmentation and placing the anchors in the posteromedial part of the greater tuberosity. Level of evidence: IV.

The Effect of Denosumab on Rotator Cuff Repair in Women Aged 60 and over with Osteoporosis: A Prospective Observational Study

BACKGROUND

In previous studies, denosumab, a RANKL human monoclonal antibody used in osteoporosis treatment, has shown efficacy in tendon healing after rotator cuff repair. This prospective study investigated the effects of denosumab on tendon healing, re-tear rates, and clinical outcomes post rotator cuff repair in women with osteoporosis.

METHOD

This was a prospective, observational study, employing propensity score matching for the control group. From March 2018 to March 2023, female patients over the age of 60 with normal bone density undergoing arthroscopic rotator cuff repair were selected as controls through propensity score matching (PSM) and compared with female patients of the same age group with osteoporosis who were receiving denosumab treatment. The control group was matched using 1-to-2 propensity score matching. Radiological examinations and functional outcomes were assessed preoperatively and at 6 months postoperatively.

RESULTS

In the final analysis, the study comprised 34 patients in the denosumab treatment group (Group 1) and 68 patients in the control group (Group 2). The functional scores showed significant improvement at 6 months post-surgery in both groups. No significant difference in the functional scores was observed among the groups. The re-tear rate, defined according to Sugaya's classification (types IV and V) as re-tear, was slightly higher in Group 1 at 16.7% (6 of 34) compared to Group 2 at 11.7% (8 of 68), but the difference was not statistically significant (p = 0.469). The re-tear patterns, classified according to Rhee's classification, also showed no significant difference among the groups (Group 1: 2/4 of 6; Group 2: 4/4 of 8; p = 0.571). The occurrence of type I re-tear exhibited no significant difference between the two groups (5.9% vs. 5.9%; p = 1.000).

CONCLUSIONS

The administration of denosumab following arthroscopic rotator cuff repair in women aged 60 and over with osteoporosis resulted in a re-tear rate that was similar to that observed in patients without osteoporosis. This result suggests that denosumab administration might be beneficial for rotator cuff healing, particularly in the context of osteoporosis, a known risk factor for increased retear rates. Therefore, comprehensive osteoporosis screening and treatment should be considered in conjunction with rotator cuff repair surgery in middle-aged women.

The Relationship Among Probable SARCopenia, Osteoporosis and SuprasPinatus Tendon Tears in Postmenopausal Women: The SARCOSP Study

We aimed to investigate the relationship among probable sarcopenia, osteoporosis (OP) and supraspinatus tendon (SSP) tears in postmenopausal women. Postmenopausal women screened/followed for OP were recruited. Demographic data, comorbidities, exercise/smoking status, and handgrip strength values were recorded. Probable sarcopenia was diagnosed as handgrip strength values < 20 kg. Achilles and SSP thicknesses were measured using ultrasound. Among 1443 postmenopausal women, 268 (18.6%) subjects had SSP tears. Unilateral tears were on the dominant side in 146 (10.1%) and on the non-dominant side in 55 women (3.8%). In contrast to those without, women with SSP tears had older age, lower level of education, thinner SSP and lower grip strength (all p < 0.05). In addition, they had higher frequencies of hypertension, hyperlipidemia, DM, OP and probable sarcopenia, but lower exercise frequency (all p < 0.05). Binary logistic regression modeling revealed that age [odds ratio (OR): 1.046 (1.024-1.067 95% CI)], hypertension [OR: 1.560 (1.145-2.124 95% CI)], OP [OR: 1.371 (1.022-1.839 95% CI)] and probable sarcopenia [OR: 1.386 (1.031-1.861 95% CI)] were significant predictors for SSP tears (all p < 0.05). This study showed that age, presence of hypertension, probable sarcopenia and OP were related with SSP tears in postmenopausal women. To this end, although OP appeared to be related to SSP tears, SSP tear/thickness evaluation can be recommended for OP patients, especially those who have other risk factors such as older age, higher BMI, hypertension, and probable sarcopenia.

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.

Tendon stem cells seeded on dynamic chondroitin sulfate and chitosan hydrogel scaffold with BMP2 enhance tendon-to-bone healing

Failure to adequately reconstruct the tendon-to-bone interface constitutes the primary etiology underlying rotator cuff retear after surgery. The purpose of this study is to construct a dynamic chondroitin sulfate and chitosan hydrogel scaffold (CHS) with bone morphogenetic protein 2 (BMP2), then seed tendon stem cells (TSCs) on BMP2-CHS for the rotator cuff reconstruction of tendon-to-bone interface. In this dynamic hydrogel system, the scaffold could not only have good biocompatibility and degradability but also significantly promote the proliferation and differentiation of TSCs. The ability of BMP2-CHS combined with TSCs to promote regeneration of tendon-to-bone interface was further verified in the rabbit rotator cuff tear model. The results showed that BMP2-CHS combined with TSCs could induce considerable collagen, fibrocartilage, and bone arrangement and growth at the tendon-to-bone interface and promote the biomechanical properties. Overall, TSCs seeded on CHS with BMP2 can enhance tendon-to-bone healing and provide a new possibility for improving the poor prognosis of rotator cuff surgery.

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.

Preoperative vitamin D supplementation is a cost-effective intervention in arthroscopic rotator cuff repair

BACKGROUND

This study investigates the potential role of preoperative 25(OH)D supplementation as a cost-effective strategy to decrease revision rotator cuff repair (RCR) rates and lower the total health care burden from patients undergoing primary arthroscopic RCR. Previous literature has emphasized the importance of vitamin D on bone health maintenance, soft tissue healing, and outcomes in RCR. Inadequate preoperative vitamin D levels may increase revision RCR rates following primary arthroscopic RCR. Although 25(OH)D deficiency is common in RCR patients, serum screening is not routinely performed.

METHODS

A cost-estimation model was developed to determine the cost-effectiveness of both preoperative selective and nonselective 25(OH)D supplementation in RCR patients in order to reduce revision RCR rates. Prevalence and surgical cost data were obtained from published literature through systematic reviews. Cost of serum 25(OH)D assay and supplementation were obtained from public-use data. Mean and lower and upper bounds of 1-year cost savings were calculated for both the selective and nonselective supplementation scenarios.

RESULTS

Preoperative 25(OH)D screening and subsequent selective 25(OH)D supplementation was calculated to result in a mean cost savings of $6,099,341 (range: -$2,993,000 to $15,191,683) per 250,000 primary arthroscopic RCR cases. Nonselective 25(OH)D supplementation of all arthroscopic RCR patients was calculated to result in a mean cost savings of $11,584,742 (range: $2,492,401-$20,677,085) per 250,000 primary arthroscopic RCR cases. Univariate adjustment projects that selective supplementation is a cost-effective strategy in clinical contexts where the cost of revision RCR exceeds $14,824.69 and prevalence of 25(OH)D deficiency exceeds 6.67%. Additionally, nonselective supplementation is a cost-effective strategy in clinical scenarios where revision RCR cost is ≥$4216.06 and prevalence of 25(OH)D deficiency is ≥1.93%.

CONCLUSIONS

This cost-predictive model promotes the role of preoperative 25(OH)D supplementation as a cost-effective mechanism to reduce revision RCR rates and lower the overall health care burden from arthroscopic RCR. Nonselective supplementation appears to be more cost-effective than selective supplementation, likely due to the lower cost of 25(OH)D supplementation compared to serum assays.

Prevalence, risk factor and outcome in middle-aged and elderly population affected by hemiplegic shoulder pain: An observational study

Background

Hemiplegic shoulder pain is the most common complication after stroke. It usually occurs during the critical period of stroke recovery and hinders the rehabilitation of upper extremity motor function. However, there are few studies on the risk factors, the development and prognosis of shoulder pain after stroke.

Objectives

This study aimed to observe the prevalence of post-stroke shoulder pain in the middle-aged and elderly population, find out the risk factors for post-stroke shoulder pain, and explore its effect on stroke outcome.

Methods

Eligible patients with hemiplegic shoulder pain in the rehabilitation unit were recruited and followed up at 2 and 4 months. The basic clinical information including age, gender, hypertension and atrial fibrillation history, stroke types, stroke location was recorded. Range of motion for shoulder, glenohumeral subluxation, muscle tension, activity of daily living of upper limb were measured. Data from blood test and shoulder ultrasonography were collected.

Results

480 stroke patients were screened within 1 year, and 239 patients were included in the statistical analysis. The prevalence of hemiplegic shoulder pain was 55.6% (133/239) at admission, 59.4% (142/239) after 2 months, and 55.1% (130/236) after 4 months. We found that shoulder pain was more likely to occur in women, patients with large-area stroke, increased tension of biceps brachii or triceps brachii, subluxation and limited passive range of motion of the shoulder. And the ability of daily living of patients with shoulder pain was significantly lower than that of patients without shoulder pain. Shoulder ultrasonography showed that the most common lesion in patients with shoulder pain was supraspinatus tendon thickening, and the thickness of supraspinatus tendon in the hemiplegic side of patients with shoulder pain was significantly higher than that of unaffected side. In addition, the hospitalization rate of patients with shoulder pain after 2 months and 4 months was significantly higher than that without shoulder pain.

Conclusions

Hemiplegic shoulder pain has a high prevalence and can last for several months. Multiple risk factors are involved. Moreover, hemiplegic shoulder pain affects the readmission rate of patients. Therefore, we should pay more attention to this problem in our clinical work. The application of various means to relieve shoulder pain will be conducive to the recovery of upper limb motor function and shorten the in-hospital rehabilitation time.

Modified Alendronate Mitigates Mechanical Degradation of the Rotator Cuff in an Osteoporotic Ovine Model

BACKGROUND

Osteoporosis is an independent risk factor for failure after arthroscopic rotator cuff repair. Since rerupture rates after rotator cuff repair are associated with decreased bone mineral density and bone microarchitecture, adaptations of biomechanical properties of the rotator cuff enthesis in patients with osteoporosis remain unclear. Additionally, the effects of osteogenic therapy carrier drugs used for the treatment of osteoporosis on rotator cuff structure and properties have not been previously documented.

PURPOSE

To investigate the changes to soft tissue biomechanics and insertional structure secondary to osteoporosis with and without an osteogenic therapy carrier (ie, modified alendronate).

STUDY DESIGN

Controlled laboratory study.

METHODS

Biomechanical, histopathological, and microcomputed tomography analyses were performed on 20 shoulders obtained from 10 osteoporotic sheep randomly allocated to modified bisphosphonate (ie, alendronate) or control (ie, osteoporotic without treatment) groups; 6 shoulders from healthy sheep were utilized for comparison purposes.

RESULTS

Tendons from the control group exhibited a 57% decrease in undeformed Young modulus as compared with the healthy group (P = .010). Tendons from the modified bisphosphonate treatment group exhibited a 229% increase in initial Young modulus as compared with the control group (P = .010). Marked changes within the tendon insertional organization were noted in both the control and the modified bisphosphonate treatment group samples as evidenced by increased interdigitation of the bone-mineralized fibrocartilaginous junction. The control samples exhibited a markedly paucicellular insertion, whereas the modified bisphosphonate treated tendons exhibited a hypercellular insertional region as compared with the healthy group. Both groups exhibited significantly (P < .01) decreased bone quality underlying the infraspinatus insertion, as evidenced by all microcomputed tomography outcome parameters.

CONCLUSION

This work illuminates changes to rotator cuff tendon secondary to osteoporosis. Specifically, it revealed decreased tendon modulus and altered insertional structure in the osteoporotic samples. Secondarily, these data revealed increases in tendon modulus accompanied by increased cellularity within the tendon insertion region after systemic modified bisphosphonate injections.

CLINICAL RELEVANCE

Bisphosphonate treatment may have a positive effect on the healing of the enthesis after rotator cuff repair.

Association of Preoperative Vitamin D Deficiency With Retear Rate and Early Pain After Arthroscopic Rotator Cuff Repair: A Retrospective Cohort Study

Background

Although the function of vitamin D in bone metabolism has been well studied, the question remains whether vitamin D deficiency impairs tendon healing after rotator cuff repair.

Purpose

To investigate the correlation between preoperative vitamin D deficiency and the retear rate and pain after arthroscopic rotator cuff repair.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair between January 2018 and August 2019 were enrolled. Included patients were divided into a control group (vitamin D level ≥20 μg/L) and a deficiency group (vitamin D level <20 μg/L). We investigated the association between preoperative vitamin D level and patient characteristics, MRI findings, pain and function scores (visual analog scale [VAS] for pain; Constant-Murley; University of California, Los Angeles; and American Shoulder and Elbow Surgeons scores), and healing status using the Pearson or Spearman correlation coefficient. The clinical characteristics were compared between the groups using the chi-square test or Fisher exact test.

Results

Included were 89 patients (control group, 44 patients; deficiency group, 45 patients). The mean vitamin D levels were 25.07 ± 5.38 and 14.61 ± 3.43 μg/L in the control and deficiency groups, respectively (P < .001); otherwise, there were no significant differences between the groups in the variables under study. Vitamin D levels were not related to age, symptom duration, tear size, extent of retraction, VAS pain score preoperatively and at 6 and 24 months postoperatively, or any function scores. Supraspinatus fatty infiltration and VAS scores at 1 and 3 months postoperatively were significantly associated with vitamin D level (r = -0.360, -0.362, and -0.316, respectively; P < .05 for all). VAS scores were significantly lower in the control group than in the deficiency group at postoperative 1 month (1.09 ± 0.56 vs 1.47 ± 0.66, respectively) and 3 months (1.14 ± 0.77 vs 1.44 ± 0.66) (P < .05 for both). The retear rate was significantly lower in the control group than in the deficiency group (9.09% vs 26.67%, respectively; P < .05).

Conclusion

Our study revealed that preoperative vitamin D deficiency was associated with a higher retear rate and early pain (1 and 3 months) after arthroscopic rotator cuff repair.

Extracellular Vesicles Delivered by Injectable Collagen Promote Bone-Tendon Interface Healing and Prevent Fatty Degeneration of Rotator Cuff Muscle

PURPOSE

This study aimed (1) to confirm the maintenance of the extracellular vesicles (EVs) delivered via injectable collagen at the application site, and (2) to evaluate the effect of EVs derived from the human umbilical cord-derived mesenchymal stem cells and loaded in an injectable collagen gel after rotator cuff repair (RCR).

METHODS

Rabbits (n = 20) were assigned to normal (N), repair-only (R), and those administered with injectable collagen after repair (RC), and EV-laden injectable collagen after repair (RCE) groups. The EVs isolated by ultra-centrifugation from the human umbilical cord-derived mesenchymal stem cells spent medium were mixed with collagen and administered accordingly. After 12 weeks, the rabbits were sacrificed to evaluate the healing of the bone-to-tendon junction and the fatty degeneration of muscle. Histomorphometric scoring for bone-tendon interface, fatty infiltration (%), and biomechanical tests were performed. Separately, groups of 3 rabbits were assigned to 3 different time points to evaluate maintenance of green fluorescence-labeled EVs with injectable collagen via tracking on the bursal side of the rotator cuff (3 groups: 3 days, 2, and 4 weeks).

RESULTS

The EVs delivered by injectable collagen remained until 4 weeks at the bursal side of the cuff tissue. The RCE group showed a significantly greater histomorphometric total score (P < .001, and P = .013, respectively) and significantly lower fatty degeneration than the RC and R groups (P = .001, and P = .013, respectively). The biomechanical tests revealed significant growing trends in load-to-failure and stiffness (P = .002, and P = .013, respectively), in the R, RC, RCE, and N groups.

CONCLUSIONS

EVs mounted in injectable collagen remained at the repair site for at least 4 weeks after application. Furthermore, they effectively promote bone-to-tendon healing via collagen maturation in bone-tendon interface and preventing fatty degeneration of rotator muscle after RCR as compared with collagen-only or repair-only groups.

CLINICAL RELEVANCE

The combination of collagen with EVs significantly promotes rotator cuff healing demonstrating potential clinical application during partial rotator cuff tear or after RCR.

Abaloparatide Improves Rotator Cuff Healing via Anabolic Effects on Bone Remodeling in a Chronic Rotator Cuff Tear Model of Rat With Osteoporosis: A Comparison With Denosumab

BACKGROUND

Because of poor clinical outcomes, rotator cuff healing in patients with osteoporosis has recently gained attention. Antiresorptive therapy for osteoporosis has been reported to improve healing after repair. However, the comparative effectiveness of anabolic and antiresorptive agents has not been investigated.

HYPOTHESIS

Anabolic therapy with abaloparatide (ABL) would outperform antiresorptive therapy with denosumab (Dmab) to improve rotator cuff healing in the osteoporotic status.

STUDY DESIGN

Controlled laboratory study.

METHODS

A chronic rotator cuff tear model was established in ovariectomy-induced postmenopausal osteoporotic rats. Then, bilateral rotator cuff repairs were conducted in all experimental rats, which were randomly divided into control (CON), Dmab, and ABL groups to receive the corresponding subcutaneous injections. The rats sacrificed at 2 weeks (the early healing period) were used to detect osteoblast and osteoclast activities, related gene expression (osteoclastogenesis, osteogenesis, and chondrogenesis), new bone formation, and mineralization. In the rats sacrificed at 4 and 8 weeks, the bone mineral density and bone architecture at the repaired site were assessed by micro-computed tomography, and rotator cuff healing was evaluated using histological and biomechanical analyses.

RESULTS

At 8 weeks, significantly higher failure load and stiffness were observed in the ABL (25.13 ± 3.54 N, P < .001; 21.65 ± 3.08 N/mm, P < .001; respectively), and Dmab (21.21 ± 2.55 N, P < .001; 16.15 ± 2.07 N/mm, P = .008; respectively) groups than in the CON group (13.36 ± 1.70 N; 11.20 ± 2.59 N/mm; respectively), whereas the ABL treatment provided better failure load and stiffness than Dmab (P = .019; P = .003). Although tendon-to-bone healing was improved by Dmab, the most mature tendon insertion at the interface was observed in the ABL group, including a more organized collagen and fibrocartilage and higher bone quality. ABL significantly promoted bone remodeling via coupling between osteoclasts and osteoblasts (osteoblast to osteoclast ratio: 4.80 ± 0.39; P = .022), thereby stimulating more new bone formation and mineralization at the tendon-to-bone healing interface than Dmab (osteoblast to osteoclast ratio: 3.21 ± 0.75) at 2 weeks. Moreover, ABL had significant effects on gene expression [Runt-realted transcription factor 2 (Runx2, collagen type I-alpha 1 (Col1A1]), and sclerostin for osteogenesis; aggrecan and collagen type II (Col2) for chondrogenesis] in mineralized tissues, indicative of enhanced bone and fibrocartilage formation when compared with the CON and Dmab groups.

CONCLUSION

ABL promoted rotator cuff healing in osteoporotic rats by significantly increasing the mineralized tissue quality and collagen maturity at the reattachment site, leading to improved biomechanical properties, and was superior to Dmab in both biomechanical and histological analyses.

CLINICAL RELEVANCE

Anabolic therapy with ABL may outperform antiresorptive therapy with Dmab in improving outcomes after rotator cuff repair in osteoporotic patients.

Osteoporosis increases the risk of rotator cuff tears: a population-based cohort study

INTRODUCTION

Osteoporosis has been demonstrated to be a risk factor for rotator cuff retears after surgery; however, no studies have directly investigated the association between osteoporosis and the development of rotator cuff tears. To investigate whether osteoporosis is associated with an increased risk of rotator cuff tears.

MATERIALS AND METHODS

We conducted a population-based, matched-cohort study with a 7-year follow-uTwo matched cohorts (n = 3511 with osteoporosis and 17,555 without osteoporosis) were recruited from Taiwan's Longitudinal Health Insurance Dataset. Person-year data and incidence rates were evaluated. A multivariable Cox model was used to derive an adjusted hazard ratio (aHR) after controlling for age, sex, and various prespecified comorbidities. Age and sex were added in the model to test for interaction with osteoporosis.

RESULTS

Women constituted 88.5% of the cohorts. During follow-up of 17,067 and 100,501 person-years for the osteoporosis and nonosteoporosis cohorts, 166 and 89 rotator cuff tears occurred, respectively. The cumulative incidence of rotator cuff tears was significantly higher in the osteoporosis cohort than in the nonosteoporosis cohort (p < 0.001, log-rank). The Cox model revealed a 1.79-fold increase in rotator cuff tears in the osteoporosis cohort, with an aHR of 1.79 (95% confidence interval, 1.55-2.05). Effect modification of sex and age on rotator cuff tears was not found in patients with osteoporosis.

CONCLUSION

This population-based study supports the hypothesis that compared with individuals without osteoporosis, those with osteoporosis have a higher risk of developing rotator cuff tears.

The role of vitamin D on rotator cuff tear with osteoporosis

BACKGROUNDS

Osteoporosis (OP) is an important risk factor for rotator cuff tears (RCTs). However, the relationship and mechanism between rotator cuff injury and osteoporosis are unclear. Therefore, to investigate association between rotator cuff injury and osteoporosis, and find clinical characteristics, bone mineral density, bone metabolism markers, and nutrient levels in rotator cuff injury patients with or without osteoporosis.

METHODS

One hundred and four cases of patients (RCTs, n=32; RCTs-OP, n=72) who underwent rotator cuff injury and need arthroscopic rotator cuff repair between June 2021 and February 2022, along with the diagnosis of osteoporosis were identified from the dual-energy X-ray bone density screening(DXA). The outcome measure includes clinical characteristics, bone mineral density, bone metabolism markers, vitamins, and amino acids. Multivariable logistic regression analysis was applied to build a predicting model incorporating the feature selected in the least absolute shrinkage and selection operator regression model. Discrimination, calibration, and clinical usefulness of the predicting model were assessed using the C-index, calibration plot, and decision curve analysis. Internal validation was assessed using bootstrapping validation.

RESULTS

OP with RCTs has a lower level of in 25-vitD, osteocalcin (OCN), serum Ca2+, ornithine, diaminocaproic_acid but the high level of Vitamin_B12, PTH, Vitamin_D3,γ_aminobutyric_acid, Vitamin_C and Vitamin_E than RCTs patients without OP. Predictors contained in the prediction nomogram included lumber T score, femur T score, Niacin_B3, and vitamin D, reflecting the combined effect of vitamins on RCTs-related OP progression. The model has good discriminative ability with a C-index of 0.938(95% CI:-1.83-1.39) and good scaling ability. The high C-index value of 0.95 is still achievable with range validation. Analysis of decision curves showed that non-adherence is clinically useful when intervention decisions are at the 14% probability limit of non-adherence.

CONCLUSION

This study supports the hypothesis that lumber T score, femur T score, Niacin_B3, and Vitamin D are valuable prognostic biomarkers on RCTs related OP progression.

WHAT IS KNOWN ABOUT THE SUBJECT

It is found that vitamin D are valuable prognostic biomarkers, reflecting the combined effect of vitamins on RCTs related OP progression.

WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE

These findings also highlight that nutrients condition such as vitamins and amino acids of patients provide a new understanding of the development of RCTs.

Effects of Platelet-Rich Plasma on Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To investigate the effect of platelet-rich plasma on tendon-bone healing after anterior cruciate ligament reconstruction.

METHODS

This retrospective study included 85 patients (range, 18-50 years; mean age, 33.95 ± 10.53 years; male/female, 49/36) who underwent anterior cruciate ligament reconstruction using autologous hamstring tendons between August 2017 and June 2019 at our institute. The participants in the study group (n = 42) were injected with platelet-rich plasma at both ends of the tendon graft, while those in the control group (n = 43) received an injection of normal saline. Magnetic resonance imaging signal/noise quotient values of the femoral and tibial ends, knee Lysholm scores, and International Knee Documentation Committee scores were compared at 3, 6, and 12 months postoperatively.

RESULTS

The signal/noise quotient values of the femoral and tibial ends in both groups were higher at 6 months than at 3 and 12 months postoperatively. The signal/noise quotient values of the tibial end were significantly lower in the platelet-rich plasma group than in the normal saline group at all follow-up time points (P < 0.05). The signal/noise quotient values of the tibial and femoral ends in both groups were significantly different at 3, 6, and 12 months postoperatively (P < 0.05). Additionally, the signal/noise quotient values of the tibia were significantly lower than those of the femur in both groups (P < 0.05). The Lysholm and International Knee Documentation Committee scores were significantly better in the platelet-rich plasma group than in the normal saline group only at 3 months postoperatively. No complications, such as knee joint infection or vascular and nerve injuries, occurred in any of the 85 patients. The knee flexion of all patients were more than 90°, and the straight degree was 0°. No joint stiffness was observed in all patients.

CONCLUSION

Platelet-rich plasma can promote tendon-bone healing in grafts and can improve early postoperative knee joint function.

Amorphous calcium phosphate nanoparticles using adenosine triphosphate as an organic phosphorus source for promoting tendon-bone healing

Background

Rotator cuff tear (RCT) is a common problem of the musculoskeletal system. With the advantage of promoting bone formation, calcium phosphate materials have been widely used to augment tendon-bone healing. However, only enhancing bone regeneration may be not enough for improving tendon–bone healing. Angiogenesis is another fundamental factor required for tendon–bone healing. Therefore, it’s necessary to develop a convenient and reliable method to promote osteogenesis and angiogenesis simultaneously, thereby effectively promoting tendon–bone healing.

Methods

The amorphous calcium phosphate (ACP) nanoparticles with dual biological activities of osteogenesis and angiogenesis were prepared by a simple low-temperature aqueous solution method using adenosine triphosphate (ATP) as an organic phosphorus source. The activities of osteogenesis and angiogenesis and the effect on the tendon–bone healing of ACP nanoparticles were tested in vitro and in a rat model of acute RCT.

Results

The ACP nanoparticles with a diameter of tens of nanometers were rich in bioactive adenosine. In vitro, we confirmed that ACP nanoparticles could enhance osteogenesis and angiogenesis. In vivo, radiological and histological evaluations demonstrated that ACP nanoparticles could enhance bone and blood vessels formation at the tendon–bone junction. Biomechanical testing showed that ACP nanoparticles improved the biomechanical strength of the tendon–bone junction and ultimately promoted tendon–bone healing of rotator cuff.

Conclusions

We successfully confirmed that ACP nanoparticles could promote tendon–bone healing. ACP nanoparticles are a promising biological nanomaterial in augmenting tendon–bone healing.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01007-y.

The Effect of Antiosteoporosis Therapy With Risedronate on Rotator Cuff Healing in an Osteoporotic Rat Model

BACKGROUND

Osteoporosis increases the revision rate of rotator cuff repair (RCR). Weak fixation might not be the only cause of high RCR failure rates. The biological mechanism associated with tendon-to-bone healing after RCR in osteoporosis should be investigated.

HYPOTHESIS

(1) Osteoporosis would impair rotator cuff healing through the high osteoclastic activity at the repaired interface. (2) Risedronate would promote rotator cuff healing by reducing osteoclastic activity at the repaired interface.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 84 female Sprague Dawley rats were randomly treated using ovariectomy or sham surgeries to establish osteoporotic and nonosteoporotic rat models. After confirming osteoporosis, a chronic rotator cuff tear model was created and RCR was performed. Postoperatively, osteoporotic rats were randomly divided into osteoporosis (OP) and osteoporosis with risedronate administration (OP+RIS) groups. Nonosteoporotic rats were used as the control (CON) group. Osteoclastic activity was measured at 1 and 3 weeks after RCR, and histologic analysis of the tendon-to-bone interface, bone morphometric evaluation, and biomechanical tests were performed at 4 and 8 weeks.

RESULTS

At the early healing stages of 1 and 3 weeks after RCR, the OP group showed the highest osteoclast density at the repaired interface. Compared with the OP group, risedronate administration significantly decreased osteoclast density in the OP+RIS group. At 8 weeks, histologic scores were greater in the OP+RIS group than in the OP group but still lower than in the CON group. Histologic scores at 8 weeks were negatively correlated with osteoclast density at the early healing stage. Additionally, the OP+RIS group showed better bone morphometric parameters and biomechanical properties than did the OP group.

CONCLUSION

Osteoporosis impaired rotator cuff healing, which might be related to the high osteoclast density at the repaired interface at the early healing stage. Postoperative risedronate administration decreased osteoclast density and enhanced rotator cuff healing in osteoporotic rats, although the effect was inferior to that in nonosteoporotic rats.

CLINICAL RELEVANCE

Postoperative risedronate administration can be considered a potential therapy to enhance rotator cuff healing in patients with postmenopausal osteoporosis. However, this needs to be verified in a clinical setting.

Poor Prognostic Factors in Patients With Rotator Cuff Retear

Background:

The treatment for retears after arthroscopic rotator cuff repair (ARCR) has long been a challenge.

Purpose:

This study aimed to (1) summarize the characteristics of patients with a retear after primary ARCR and (2) determine the risk factors for poor clinical outcomes after a retear.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We collected the data of patients with a retear after primary ARCR between January 2011 and December 2016. There were 45 patients with retears included (19 men [42.2%] and 26 women [57.8%]; mean ± SD age, 63.11 ± 8.87 years). Initially, the demographic and outcome data of patients with a retear were analyzed. Patients were classified into good and poor outcome groups according to their overall satisfaction at final follow-up. Univariable and multivariable logistic regression analyses were performed to determine the factors for poor clinical outcomes after a retear.

Results:

A total of 31 patients were classified into the good outcome group, and 14 patients were classified into the poor outcome group. Both the good and the poor outcome groups showed that clinical scores significantly improved at the time of the retear diagnosis, but the final scores were maintained or worse compared with scores at the time of the retear diagnosis. Final range of motion (ROM), except external rotation in the good outcome group, was worse or had no significant change compared with ROM at the time of the retear diagnosis. On multivariable logistic regression analysis, current smoking (odds ratio [OR], 45.580 [95% CI, 3.014-689.274]; P = .006), female sex (OR, 32.774 [95% CI, 2.433-441.575]; P = .009), and retears of the same or larger size than the initial tear (OR, 10.261 [95% CI, 1.544-68.202]; P = .016) showed a higher OR for poor clinical outcomes after a retear.

Conclusion:

Smoking, female sex, and retears of the same or larger size than the initial tear were independent risk factors for poor clinical outcomes after a rotator cuff retear. Final clinical scores and ROM were similar or worse compared with the scores and ROM at the time of the retear diagnosis. Therefore, revision surgery should be actively considered in female patients or those who smoke with poor clinical outcomes and a larger retear size than the preoperative tear size at the time of the retear diagnosis.