The Association of Osteoporosis and Bisphosphonate Use With Revision Shoulder Surgery After Rotator Cuff Repair

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.

A Systematic Review and Meta-analysis of Risk Factors for the Increased Incidence of Revision Surgery After Arthroscopic Rotator Cuff Repair

BACKGROUND

Approximately 90% of patients who undergo arthroscopic rotator cuff repair (RCR) are satisfied with their pain levels and function after surgery. However, a subset of patients experience continued symptoms that warrant revision surgery. Preoperative risk factors for RCR failure requiring revision surgery have not been clearly defined.

PURPOSE

To (1) determine the rate of RCR failure requiring revision surgery and (2) identify risk factors for revision surgery, which will help surgeons to determine patients who are at the greatest risk for RCR failure.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A systematic review and meta-analysis in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were performed. The initial search resulted in 3158 titles, and 533 full-text articles were assessed for eligibility. A total of 10 studies met the following inclusion criteria: (1) human clinical studies, (2) arthroscopic RCR, (3) original clinical research, and (4) evaluation of preoperative risk factors for revision.

RESULTS

After a full-text review, a total of 16 risk factors were recorded and analyzed across 10 studies. Corticosteroid injection was the most consistent risk factor for revision surgery, reaching statistical significance in 4 of 4 studies, followed by workers' compensation status (2/3 studies). Patients with corticosteroid injections had a pooled increased risk of revision surgery by 47% (odds ratio, 1.44 [95% CI, 1.36-1.52]). Patients with workers' compensation had a pooled increased risk of revision surgery by 133% (odds ratio, 2.33 [95% CI, 2.09-2.60]). Age, smoking status, diabetes, and obesity were found to be risk factors in half of the analyzed studies.

CONCLUSION

Corticosteroid injections, regardless of the frequency of injections, and workers' compensation status were found to be significant risk factors across the literature based on qualitative analysis and pooled analysis. Surgeons should determine ideal candidates for arthroscopic RCR by accounting for corticosteroid injection history, regardless of the frequency, and insurance status of the patient.

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.

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.

Macroporous Granular Hydrogels Functionalized with Aligned Architecture and Small Extracellular Vesicles Stimulate Osteoporotic Tendon-To-Bone Healing

Osteoporotic tendon-to-bone healing (TBH) after rotator cuff repair (RCR) is a significant orthopedic challenge. Considering the aligned architecture of the tendon, inflammatory microenvironment at the injury site, and the need for endogenous cell/tissue infiltration, there is an imminent need for an ideal scaffold to promote TBH that has aligned architecture, ability to modulate inflammation, and macroporous structure. Herein, a novel macroporous hydrogel comprising sodium alginate/hyaluronic acid/small extracellular vesicles from adipose-derived stem cells (sEVs) (MHA-sEVs) with aligned architecture and immunomodulatory ability is fabricated. When implanted subcutaneously, MHA-sEVs significantly improve cell infiltration and tissue integration through its macroporous structure. When applied to the osteoporotic RCR model, MHA-sEVs promote TBH by improving tendon repair through macroporous aligned architecture while enhancing bone regeneration by modulating inflammation. Notably, the biomechanical strength of MHA-sEVs is approximately two times higher than the control group, indicating great potential in reducing postoperative retear rates. Further cell-hydrogel interaction studies reveal that the alignment of microfiber gels in MHA-sEVs induces tenogenic differentiation of tendon-derived stem cells, while sEVs improve mitochondrial dysfunction in M1 macrophages (Mφ) and inhibit Mφ polarization toward M1 via nuclear factor-kappaB (NF-κb) signaling pathway. Taken together, MHA-sEVs provide a promising strategy for future clinical application in promoting osteoporotic TBH.

Association of obesity with high retears and complication rates, and low functional scores after rotator cuff repair: a systematic review and meta-analysis

BACKGROUND

Obesity influences the outcomes of orthopedic surgeries such as total knee arthroplasty and spinal surgery. However, the effect of obesity on the outcomes of rotator cuff repair is unknown. This systematic review and meta-analysis aimed to examine the effect of obesity on rotator cuff repair outcomes.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched to identify relevant studies published from their inception till July 2022. Two reviewers independently screened titles and abstracts using the specified criteria. Articles were included if they indicated the effect of obesity on rotator cuff repair and the related outcomes after surgery. Review Manager 5.4.1 software was used to perform statistical analysis.

RESULTS

Thirteen articles involving 85,497 patients were included. Obese patients had higher retear rates than nonobese patients (odds ratio [OR] 2.58, 95% confidence interval [CI] 1.23-5.41, P = .01), lower American Shoulder and Elbow Surgeons scores (mean difference [MD]: -3.59, 95% CI: -5.45 to [-1.74]; P = .0001), higher visual analog scale for pain (mean difference: 0.73, 95% CI: 0.29-1.17; P = .001), higher reoperation rates (OR 1.31, 95% CI 1.21-1.42, P < .00001), and higher rates of complications (OR 1.57, 95% CI 1.31-1.87, P = .000). Obesity did not affect the duration of surgery (MD: 6.03, 95% CI: -7.63 to 19.69; P = .39) or external rotation of the shoulder (MD: -1.79, 95% CI: -5.30 to 1.72; P = .32).

CONCLUSION

Obesity is a significant risk factor for retear and reoperation after rotator cuff repair. Furthermore, obesity increases the risk of postoperative complications and leads to lower postoperative American Shoulder and Elbow Surgeons scores and higher shoulder visual analog scale for pain.

Abnormal Laboratory Values for Metabolic and Hormonal Syndromes Are Prevalent Among Patients Undergoing Rotator Cuff Repair

Purpose

To determine the prevalence of systemic laboratory abnormalities among patients undergoing rotator cuff repair (RCR).

Methods

Patients who underwent RCR at the authors' institution for 1 year between October 2021 to September 2022 were retrospectively identified. Preoperative laboratory values, including serum sex hormones, vitamin D, hemoglobin A1C, and a lipid panel, were obtained as part of our routine practice during the study period. Demographics and tear characteristics were compared in patients with laboratory data and those without. For included patients with laboratory data, mean laboratory values and percentage of patients with abnormal laboratory values were recorded.

Results

During a 1-year period of time, 135 RCRs were performed, of which preoperative labs were obtained on 105. Of these, 67% were sex hormone deficient, 36% were vitamin D deficient, 45% had an abnormal hemoglobin A1C, and 64% had an abnormal lipid panel. In total 4% had "normal" labs.

Conclusions

In this retrospective study, sex hormone deficiency is highly prevalent among patients undergoing RCR. Nearly all patients undergoing RCR have systemic laboratory abnormalities involving either sex hormone deficiency, vitamin D deficiency, dyslipidemia, and/or prediabetes.

Level of Evidence

Level IV, prognostic case series.

Does the Fatty Infiltration Influence the Re-tear Rate and Functional Outcome After Rotator Cuff Repair? A Systematic Review and Meta-analysis

Purpose

Fatty infiltration (FI) of the rotator cuff muscles occurs after rotator cuff tears (RCTs), which may affect the outcome of the repair procedure. This study aimed to determine the relationship between preoperative FI and the rate of re-tear and functional outcomes after rotator cuff repair.

Methods

Computerized databases, including PubMed, EMBASE, Web of Science, and Cochrane Library database were searched for studies published from the inception date to January 2022. Two reviewers independently screened the titles and abstracts using prespecified criteria. Articles were included if they clearly stated the effect of varying degrees of FI on the outcome after shoulder cuff repair. Comparison was performed by different degrees of FI analysis: no FI is grade 0-1, FI is grade 2 and above. Statistical analysis was performed using Review Manager 5.4.1 software.

Results

A total of 16 articles involving 1383 patients from 8 countries were included. The follow-up period ranged from 8 to 121 months. In terms of re-tear rate: patients with preoperative FI had significantly higher rates of re-tear compared with patients without FI (OR 4.60, 95% CI 2.22-9.54, p < 0.0001), supraspinatus FI VS no FI (OR 2.06, 95% CI 1.00-4.24, p = 0.05), infraspinatus FI VS no FI (OR 2.42, 95% CI 1.19-4.91, p = 0.01). In terms of functional scoring: patients without FI had higher postoperative Constant-Murley (Constant) scores than those with FI (MD - 5.06, 95% CI - 9.40 to - 0.72, p = 0.02), there was no clear evidence that preoperative FI was related to postoperative American Society of shoulder and elbow physicians scores and the University of California at Los Angeles scores and range of motion.

Conclusion

FI after RCTs significantly increases the risk of postoperative re-tear and leads to worse functional scores, especially FI of the infraspinatus muscle. However, FI does not seem to reduce postoperative range of motion.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00807-0.

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.

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.

Complications, readmission rates, and in-hospital lengths-of-stay in octogenarian vs. non-octogenarians following total knee arthroplasty: An analysis of over 1.7 million patients

INTRODUCTION

Studies investigating complications between octogenarians and non-octogenarians undergoing primary total knee arthroplasty (TKA) are limited. Therefore, we investigated whether octogenarians are at greater odds of: (1) in-hospital lengths of stay (LOS) (2) readmission rates, (3) medical complications, and (4) hardware complications compared to non-octogenarians following TKA.

METHODS

A retrospective query of the PearlDiver database isolated 1,775,460 patients who underwent primary TKA from 2005 to 2014. Patients aged 80 and above represented the study cohort (n = 295,908) and patients 65 to 79 represented the control cohort (n = 1,479,552). Study group patients were matched to controls in a 1:5 ratio according to gender and medical comorbidities. Pearson's Chi Square and logistic regression were used to analyze the primary outcomes of the study which included 90-day medical complications, 90-day readmission rates, 2-year implant-related complications, and in-hospital LOS. A p-value less than 0.001 was statistically significant.

RESULTS

Octogenarians were found to have significantly higher incidence and odds of 90-day readmission rates (10.59 vs. 9.35%; OR: 1.15, p < 0.0001) and significantly longer in-hospital LOS (3.69 days ± 1.95 vs. 3.23 days ± 1.83, p < 0.0001) compared to controls. Octogenarians also had equal incidence and odds of developing any medical complication (1.26 vs. 1.26%; OR: 0.99, p = 0.99) and lower incidence and odds (1.67 vs. 1.93%; OR: 0.86, p < 0.001) of implant-related complications compared to controls.

CONCLUSION

Octogenarians undergoing primary TKA have similar odds of medical related complications and lower odds of implant-related complications compared to non-octogenarian patients, whereas readmission rates and in-hospital LOS are greater.

The Use of Intravenous Zoledronate May Reduce Retear Rate after Rotator Cuff Repair in Older Female Patients with Osteoporosis. A First In-Human Prospective Study

The objective of this study was to demonstrate the effect of intravenous (IV) zoledronate administration on rotator cuff healing, retear rate, and clinical outcomes in osteoporotic patients who underwent arthroscopic rotator cuff repair (ARCR) compared with patients with normal bone densities. In this prospective nonrandomized comparative study with propensity score matching, 30 patients who were postoperatively administered IV zoledronate (5 mg) were enrolled as the study group. The control group was matched using 1-to-2 propensity score matching. Radiologic and functional outcomes were evaluated 6 months after surgery. The functional scores in both groups exhibited significant improvement 6 months after surgery. Compared with Group 1 (osteoporosis with IV zoledronate injection) Group 2 (normal bone density) showed significant improvement in their University of California, Los Angeles (UCLA) shoulder score and Constant Shoulder Score (CSS) at 6 months postoperatively. The range of motion improved in both groups at 6 months after surgery. The retear rates according to Sugaya’s classification (IV and V) were 13.3% (4 of 30 patients) and 25% (15 of 60 patients) in Groups 1 and 2, respectively, which established a non-inferiority of Group 1 to the control group. The retear pattern according to Rhee’s classification in Group 1 was type I in all cases, whereas eight cases of type I and seven cases of type II patterns were observed in Group 2, which was statistically insignificant between the groups. In conclusion, anti-osteoporotic drug use is beneficial for patients with osteoporosis to reduce the failure rate after an ARCR of length > 2 cm, especially in older female patients. Moreover, thorough scrutiny is required to detect osteoporosis in patients with rotator cuff tears, especially in female patients.

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.

Can magnetic resonance imaging accurately and reliably measure humeral cortical thickness?

Background

Historically, imaging osseous detail in three dimensions required a computed tomography (CT) scan with ionizing radiation that poorly visualizes the soft tissues. The purpose of this study was to determine the accuracy and reliability of ultrashort echo time (UTE) magnetic resonance imaging (MRI) in measuring humeral cortical thickness and cancellous density as compared with CT.

Methods

This was a comparative radiographic study in nine cadavers, each of which underwent CT and UTE MRI. On images aligned to the center of the humeral shaft, anterior, posterior, medial, and lateral humeral cortical thickness was measured 5, 10, and 15 cm distal to the top of the head. Cancellous density was measured as signal within a 1-cm diameter region of interest in the center of the head, the subtuberosity head, the subarticular head, and the subarticular glenoid vault. Glenoid cortical thickness was measured at the center of the glenoid. Cortical measurements were compared using mean differences and 95% confidence intervals, paired Student’s t-tests, and intraclass correlation coefficients (ICCs). We compared cancellous measurements using Pearson’s correlation coefficients. For all measurements, we calculated interobserver and intraobserver reliability using ICCs with 0.75 as the lower limit for acceptability.

Results

With regard to accuracy, for humeral cortical thickness measurements, there were no significant differences between MRI and CT measures, and ICCs were >0.75. The glenoid cortical thickness ICC was <0.75. There was no significant correlation between the cancellous signal on MRI and on CT in any region. For both MRI and CT, interobserver reliability and intraobserver reliability were acceptable (ie, >0.75) for almost all humeral cortical thickness measures.

Conclusion

UTE MRI can reliably and accurately measure humeral cortical thickness, but cannot accurately measure cancellous density or accurately and reliably measure glenoid cortical thickness.

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.

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.

Greater Tuberosity Bone Mineral Density and Rotator Cuff Tear Size Are Independent Factors Associated With Cutting-Through in Arthroscopic Suture-Bridge Rotator Cuff Repair

PURPOSE

To evaluate the correlation between cutting-through at the greater tuberosity (GT) in arthroscopic suture-bridge rotator cuff repair and the bone mineral density (BMD) of the lumbar spine, hip, and ipsilateral GT of the proximal humerus and to evaluate factors and clinical outcomes related to cutting-through.

METHODS

This study prospectively enrolled patients who underwent arthroscopic knotted suture-bridge rotator cuff repair for full-thickness rotator cuff tears between June 2014 and October 2015 and who had undergone dual-energy X-ray absorptiometry cans within 1 month before surgery with a minimum 2-year follow-up. Cutting-through was defined as the occurrence of cortical breakage of the GT just medial to the lateral knotless anchor hole due to the tension of the sutures from the medial anchor, and it was assessed. Clinical and radiologic data were analyzed. Univariate and regression analyses were performed to evaluate factors related to cutting-through.

RESULTS

A total of 78 patients were analyzed. Patients were divided into 2 groups: patients who had cutting-through (46, group I) and patients who did not (32, group II). In an analysis of lumbar spine, hip, and GT BMD, GT BMD was the most effective for predicting cutting-through (area under the receiver operating characteristic curve = 0.94, 95% confidence interval 0.89-0.99). GT BMD (P < .001) and tear size (P = .004) were independent factors for cutting-through. Although a significant difference was found between the 2 groups in terms of age, sex, lumbar spine and hip BMD, fatty infiltration of the supraspinatus and infraspinatus, and atrophy of the supraspinatus, these variables were not independent factors. Clinical and structural outcomes showed no significant difference between the 2 groups, and anchor failure was not identified intraoperatively.

CONCLUSIONS

GT BMD and rotator cuff tear size are independent factors associated with cutting-through at the GT. A dual-energy X-ray absorptiometry scan of the proximal humerus is useful for predicting bone quality before arthroscopic suture-bridge rotator cuff repair.

LEVEL OF EVIDENCE

Level II, Prospective cohort study.

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.

Osteoporosis Screening Is Often Indicated but Overlooked Prior to Rotator Cuff Repair

Purpose

To (1) report the percentage of patients undergoing rotator cuff repair (RCR) who were appropriately screened with dual-energy X-ray absorptiometry testing prior to surgery, if indicated, and (2) determine the percentage of patients properly prescribed osteoporosis medications within 6 months of surgery.

Methods

Consecutive patients aged 50 years or older who underwent elective RCR at a single tertiary-care center over a 1-year period were reviewed. Fracture risk was estimated using the Fracture Risk Assessment Tool (FRAX) with and without bone mineral density. The U.S. National Osteoporosis Foundation (NOF) criteria for screening and treatment were applied. Patients with acute fractures or revision surgery were excluded.

Results

Of the 218 patients included, 129 were women (58.1%). The mean age was 61.5 ± 7.2 years. One hundred thirty-one RCRs (60.1%) occurred within 3 months of injury. A total of 69 patients (31.7%) met the NOF criteria for bone mineral density screening. Of these patients, 23 (33.3%) were appropriately screened with a dual-energy X-ray absorptiometry scan. Primary care providers initiated bone health assessment in 18 of the 23 appropriately screened patients, with orthopaedic providers initiating the workup in 3 patients (13.0%). Thirty-two patients (14.7%) met the NOF criteria for pharmacologic management of osteoporosis. Of these patients, 5 (15.6%) were treated. Patients meeting the medication criteria were older (69.1 ± 7.7 years vs 60.2 ± 6.3 years, P < .001), had a lower body mass index (28.8 ± 6.1 vs 31.5 ± 6.5, P = .028), and had chronic rotator cuff tears (P = .015).

Conclusions

Patients aged 50 years or older undergoing RCR are often not appropriately screened for osteoporosis. Even when appropriately screened, only 15.6% of patients meeting the indications for pharmacologic intervention for bone health optimization were prescribed appropriate medications. Although bone health optimization may or may not affect surgical timing, patient encounters related to rotator cuff tears can be used as an opportunity for providers to initiate osteoporosis screening and treatment protocols.

Level of Evidence

Level IV, therapeutic case series.

The Effect of Patient Characteristics and Comorbidities on the Rate of Revision Rotator Cuff Repair

PURPOSE

To describe the national rates of failed primary rotator cuff repair (RCR) requiring revision repair, using numerous patient characteristics previously defined in orthopaedic literature, including smoking history, diabetes mellitus (DM), hyperlipidemia (HLD), vitamin D deficiency, and osteoporosis to determine which factors independently affect the success of primary RCR.

METHODS

A combined public and private national insurance database was searched from 2007 to 2016 for all patients who underwent RCR. Current Procedural Terminology codes were used to identify RCRs. Laterality modifiers for the primary surgery were used to identify subsequent revision RCRs. All patients who did not have a linked laterality modifier for the RCR Current Procedural Terminology code were excluded from the study. Basic demographics were recorded. International Classification of Diseases Ninth Revision codes were used to identify patient characteristics including Charlson Comorbidity Index, smoking status, DM, obesity, HLD, vitamin D deficiency, and osteoporosis. Patient age categorized as <60, 60-69, 70-74, or 75+ years old. Dichotomous data were analyzed with χ² testing. Multivariable logistic regression was used to characterize independent associations with revision RCR.

RESULTS

Included in the study were 41,467 patients (41,844 shoulders, 52.7% male patients) who underwent primary arthroscopic RCR. Of all arthroscopic RCRs, 3072 patients (3463 shoulders, 53.5% male patients) underwent revision RCR (8.38%). In both primary and revision RCR, patients age 60 to 69 years were most prevalent, accounting for 38.4% and 37.6% of the cohorts, respectively. The average time from primary RCR to revision was 414.9 days (median 214.0 days). Increasing age and male sex (odds ratio [OR] 1.10, P = .019, 95% confidence interval [CI] 1.02-1.19) were significantly predictive of revision RCR. Of the remaining patient characteristics, smoking most strongly predicted revision RCR (OR 1.36, P < .001, CI 1.23-1.49). Obesity (OR 1.32, P < .001, CI 1.21-1.43), hyperlipidemia (OR 1.09, P = .032, CI 1.01-1.18), and vitamin D deficiency (OR 1.18, P < .001, CI 1.08-1.28) also increased risk of revision RCR significantly. DM was found to be protective against revision surgery (OR 0.84, P < .001, CI 0.76-0.92). Overall comorbidity burden as measured by the Charlson Comorbidity Index was not predictive of revision RCR.

CONCLUSIONS

Smoking, obesity, vitamin D deficiency, and HLD are shown to be independent risk factors for failure of primary RCR requiring revision RCR. However, despite the suggestions of previous studies, DM, osteoporosis, and overall comorbidity burden did not demonstrate independent associations in this study.

LEVEL OF EVIDENCE

IV, Case Series.

Factors Influencing the Reparability and Healing Rates of Rotator Cuff Tears

PURPOSE OF THE REVIEW

To discuss tear- and patient-related factors that influence the healing potential of rotator cuff tears and to clarify the terminology surrounding this topic.

RECENT FINDINGS

Over the last few years, further insight has been gained regarding rotator cuff tear features that are associated with poor healing rates after rotator cuff repair. Some of these features have been incorporated in prediction models developed to accurately predict rotator cuff healing rates utilizing preoperative risk factors weighted by importance. Rotator cuff tears may be considered functionally irreparable based on their size, chronicity, absence of adequate tendon length, atrophy, and fatty infiltration. Furthermore, advanced age, use of tobacco products, diabetes, and other patient-related factors may impair tendon healing. Careful analysis and discussion of all these factors with patients is essential to determine if surgical repair of a rotator cuff tear should be recommended, or if it is best to proceed with one of the several salvage procedures reviewed in this topical collection, including augmentation of the repair, superior capsular reconstruction, tendon transfers, and other.

Zoledronic Acid Substantially Improves Bone Microarchitecture and Biomechanical Properties After Rotator Cuff Repair in a Rodent Chronic Defect Model

BACKGROUND

Bone mineral density at the humeral head is reduced in patients with chronic rotator cuff tears. Bone loss in the humeral head is associated with repair failure after rotator cuff reconstruction. Bisphosphonates (eg, zoledronic acid) increase bone mineral density.

HYPOTHESIS

Zoledronic acid improves bone mineral density of the humeral head and biomechanical properties of the enthesis after reconstruction of chronic rotator cuff tears in rats.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 32 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy with delayed transosseous rotator cuff reconstruction after 3 weeks. All rats were sacrificed 8 weeks after rotator cuff repair. Animals were randomly assigned to 1 of 2 groups. At 1 day after rotator cuff reconstruction, the intervention group was treated with a single subcutaneous dose of zoledronic acid at 100 µg/kg bodyweight, and the control group received 1 mL of subcutaneous saline solution. In 12 animals of each group, micro-computed tomography scans of both shoulders were performed as well as biomechanical testing of the supraspinatus enthesis of both sides. In 4 animals of each group, histological analyses were conducted.

RESULTS

In the intervention group, bone volume fraction (bone volume/total volume [BV/TV]) of the operated side was higher at the lateral humeral head (P = .005) and the medial humeral head (P = .010) compared with the control group. Trabecular number on the operated side was higher at the lateral humeral head (P = .004) and the medial humeral head (P = .001) in the intervention group. Maximum load to failure rates on the operated side were higher in the intervention group (P < .001). Cortical thickness positively correlated with higher maximum load to failure rates in the intervention group (r = 0.69; P = .026). Histological assessment revealed increased bone formation in the intervention group.

CONCLUSION

Single-dose therapy of zoledronic acid provided an improvement of bone microarchitecture at the humeral head as well as an increase of maximum load to failure rates after transosseous reconstruction of chronic rotator cuff lesions in rats.

CLINICAL RELEVANCE

Zoledronic acid improves bone microarchitecture as well as biomechanical properties after reconstruction of chronic rotator cuff tears in rodents. These results need to be verified in clinical investigations.

Chronic kidney disease-related osteoporosis is associated with incident frailty among patients with diabetic kidney disease: a propensity score-matched cohort study

Chronic kidney disease (CKD)-related osteoporosis is a major complication in patients with CKD, conferring a higher risk of adverse outcomes. We found that among those with diabetic kidney disease, this complication increased the risk of incident frailty, an important mediator of adverse outcomes.

INTRODUCTION

Renal osteodystrophy and chronic kidney disease (CKD)-related osteoporosis increases complications for patients with diabetic kidney disease (DKD). Since musculoskeletal degeneration is central to frailty development, we investigated the relationship between baseline osteoporosis and the subsequent frailty risk in patients with DKD.

METHODS

From the Longitudinal Cohort of Diabetes Patients in Taiwan (n = 840,000), we identified 12,027 patients having DKD with osteoporosis and 24,054 propensity score-matched controls having DKD but without osteoporosis. The primary endpoint was incident frailty on the basis of a modified FRAIL scale. Patients were prospectively followed-up until the development of endpoints or the end of this study. The Kaplan-Meier technique and Cox proportional hazard regression were used to analyze the association between osteoporosis at baseline and incident frailty in these patients.

RESULTS

The mean age of the DKD patients was 67.2 years, with 55.4% female and a 12.6% prevalence of osteoporosis at baseline. After 3.5 ± 2.2 years of follow up, the incidence rate of frailty in patients having DKD with osteoporosis was higher than that in DKD patients without (6.6 vs. 5.7 per 1000 patient-year, p = 0.04). A Cox proportional hazard regression showed that after accounting for age, gender, obesity, comorbidities, and medications, patients having DKD with osteoporosis had a significantly higher risk of developing frailty (hazard ratio, 1.19; 95% confidence interval, 1.02-1.38) than those without osteoporosis.

CONCLUSIONS

CKD-related osteoporosis is associated with a higher risk of incident frailty in patients with DKD.

Calcium Phosphate Bone Void Filler Increases Threaded Suture Anchor Pullout Strength: A Biomechanical Study

PURPOSE

To compare the response to cyclical loading and ultimate pull-out strength of threaded suture anchor with and without calcium phosphate bone void filler augmentation in a polyurethane foam block model and in vitro proximal humerus cadaveric model.

METHODS

This controlled biomechanical study consisted of 2 parts: (1) preliminary polyurethane foam block model, and (2) in vitro cadaveric humeri model. The preliminary foam block model intended to mimic osteoporotic bone using a 0.12 g/mL foam material. Half of the foam block models were first filled with injectable calcium phosphate bone substitute material (CP-BSM), whereas the other half were not augmented with CP-BSM. Each specimen was then instrumented with a threaded suture anchor. The same technique and process was performed in a matched cadaveric humeri model. Testing then consisted of a stepwise, increasing axial load protocol for a total of 40 cycles. If the anchor remained intact after cyclic loading, the repair was loaded to failure. The number of completed cycles, failure load, and failure modes were compared between groups.

RESULTS

Average pull-out strength for suture anchor with CP-BSM in the osteoporotic foam block model was significantly higher at 332.68 N ± 47.61 compared with the average pull-out strength of suture anchor without CP-BSM at 144.38 N ± 14.58 (P = .005). In the matched cadaveric humeri model, average pull-out strength for suture anchor with CP-BSM was significantly higher at 274.07 N ± 102.07 compared with the average pull-out strength of suture anchor without CP-BSM at 138.53 N ± 109.87 (P = .029).

CONCLUSIONS

In this time zero, biomechanical study, augmentation of osteoporotic foam block and cadaveric bone with calcium phosphate bone substitute material significantly increases pull-out strength of threaded suture anchors.

CLINICAL RELEVANCE

Considering concerns about suture anchor pull-out from osteoporotic bone, augmentation with calcium phosphate bone substitute material increases load to failure resistance.

Editorial Commentary: Aging and Rotator Cuff Tears

Osteoporosis is associated with failure of rotator cuff repair. Optimizing bone density, as well as rotator cuff tendon-to-bone fixation in an osteoporotic humeral head, is a necessary approach to the patient as a whole.