The level of vitamin D in the serum correlates with fatty degeneration of the muscles of the rotator cuff

Editorial Commentary: Testosterone, Growth Hormone, and Vitamin D Supplementation Is Not Routinely Indicated for Orthopaedic Surgery Patients

Endocrinologists and family medicine physicians prescribe testosterone replacement therapy (TRT) for decreased levels of androgens in aging males. Benefits include improvements in mood, cognition, libido, energy, and quality of life. In orthopaedic surgery patients of both sexes, benefits could also include improvements in functional outcomes, bone mineral density, lean body mass, and early mobilization. A challenge is that patients may request supplementation with TRT and other supplements, including vitamin D (which may benefit fracture healing, bone metabolism, muscle recovery, and healing of tendons and wounds) and growth hormones (specifically BPC 157, which may optimize endurance training, metabolism, tissue repair, and surgical recovery). However, TRT and other supplements have risks and may not be indicated. TRT is not recommended for routine use in the perioperative management of orthopaedic surgery patients.

The role of vitamin D in shoulder health: a comprehensive review of its impact on rotator cuff tears and surgical results

Vitamin D deficiency is highly prevalent in the general population and is associated with various chronic health conditions. In addition to its role in bone mineralization, Vitamin D has various physiological effects that may impact the pathogenesis of shoulder pathologies. Vitamin D deficiency may also affect outcomes after shoulder surgeries, such as rotator cuff repair and total shoulder arthroplasty. Vitamin D plays a role in tissue healing, bone growth, and maintenance of homeostasis in skeletal muscle cells. Vitamin D also has anti-inflammatory effects that are important to rotator cuff health. Vitamin D deficiency is highly prevalent in patients with rotator cuff tears, suggesting its role as a potential risk factor. Vitamin D deficiency has been associated with decreased preoperative shoulder strength as well as increased re-tear rates, postoperative stiffness, and the need for revision surgery in patients who underwent rotator cuff repair. Studies have also demonstrated a potential association between vitamin D deficiency and increased risk of revision after total shoulder arthroplasty. Further research is necessary to elucidate the direct role of vitamin D in the pathogenesis of rotator cuff tears and its impact on clinical outcomes after rotator cuff surgery and total shoulder arthroplasty.

Exploring the impact of vitamin D on tendon health: a comprehensive review

Tendons are vital components of the musculoskeletal system, facilitating movement and supporting mechanical loads. Emerging evidence suggests that vitamin D, beyond its well-established role in bone health, exerts significant effects on tendon physiology. The aim of this manuscript is to review the impact of vitamin D on tendons, focusing on its mechanisms of action, clinical implications, and therapeutic applications. A comprehensive search of scientific electronic databases was conducted to identify articles on the effects of vitamin D on tendon health. Fourteen studies were included in this review. Five studies were performed in vitro, and nine studies were conducted in vivo. Despite some conflicting results, the included studies showed that vitamin D regulates collagen synthesis, inflammation, and mineralization within tendons through its interaction with vitamin D receptors. Epidemiological studies link vitamin D deficiency with tendon disorders, including tendinopathy and impaired healing. Supplementation with vitamin D shows promise in improving tendon strength and function, particularly in at-risk populations such as athletes and the elderly. Future research should address optimal supplementation strategies and explore the interplay between vitamin D and other factors influencing tendon health. Integrating vitamin D optimization into clinical practice could enhance tendon integrity and reduce the burden of tendon-related pathologies.

The Role of Perioperative Nutritional Status and Supplementation in Orthopaedic Surgery: A Review of Postoperative Outcomes

» Identification of malnourished and at-risk patients should be a standardized part of the preoperative evaluation process for every patient.» Malnourishment is defined as a disorder of energy, protein, and nutrients based on the presence of insufficient energy intake, weight loss, muscle atrophy, loss of subcutaneous fat, localized or generalized fluid accumulation, or diminished functional status.» Malnutrition has been associated with worse outcomes postoperatively across a variety of orthopaedic procedures because malnourished patients do not have a robust metabolic reserve available for recovery after surgery.» Screening assessment and basic laboratory studies may indicate patients' nutritional risk; however, laboratory values are often not specific for malnutrition, necessitating the use of prognostic screening tools.» Nutrition consultation and perioperative supplementation with amino acids and micronutrients are 2 readily available interventions that orthopaedic surgeons can select for malnourished patients.

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.

Effect of Vitamin D Deficiency on Voice: A Review of the Literature

OBJECTIVE

The purpose of this study is to review the current literature on the effect of hypovitaminosis D on voice.

STUDY DESIGN

Narrative review.

METHODS

The literature search from electronic databases included PubMed/MEDLINE, EMBASE, SCOPUS, and Google Scholar. Search terms included voice, voice quality, voice disorders, larynx, laryngology, acoustic analysis, vitamin D, calcitriol, cholecalciferol, vitamin D deficiency, and vitamin D insufficiency. All studies on patients with vitamin D deficiency, which included subjective and objective voice assessments, were reviewed.

RESULTS

A total of 39 studies were retrieved. Only four studies met the above-mentioned inclusion criteria and hence were included in this review. The total number of subjects analyzed was 466. The subjective voice outcome measures used were the Voice Handicap Index-10 (VHI-10), self-reported phonatory symptoms, and the GRBAS scale. Objective voice outcome measures included fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, maximum phonation time, and dysphonia severity index.

CONCLUSION

Vitamin D deficiency has no significant effect on laryngeal muscles. There was no statistically significant difference in VHI-10 score, self-reported dysphonia, perceptual voice evaluation scores, or any of the acoustic measures between those with or without vitamin D deficiency.

Serum Vitamin D Level Correlations With Tissue Vitamin D Level and Muscle Performance Before and After Rotator Cuff Repair

BACKGROUND

There is a lack of studies about serum and tissue vitamin D levels of the rotator cuff muscle on muscle power, fatty degeneration, and healing failure after rotator cuff repair (RCR). Furthermore, no studies have evaluated vitamin D receptor proteins in the rotator cuff that show a close association with serum vitamin D levels.

PURPOSE

To evaluate the correlations between serum vitamin D and tissue vitamin D as well as perioperative variables of arthroscopic RCR.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From March 2017 to October 2017, a total of 36 patients who underwent RCR were prospectively enrolled, and supraspinatus muscle tissue was obtained during surgery to analyze tissue vitamin D levels. Serum vitamin D levels were checked preoperatively and at 6 months and 1 year postoperatively. Tissue vitamin D levels were assessed using liquid chromatography, and the vitamin D receptor was measured by western blotting. Isokinetic muscle performance test (IMPT; peak torque and torque deficiency compared with the opposite shoulder) results and fatty degeneration of the rotator cuff using the Goutallier classification were assessed preoperatively and at 1 year after surgery. The American Shoulder and Elbow Surgeons score and Constant score were collected at 2 years after surgery. Healing failure of the repaired rotator cuff was analyzed by magnetic resonance imaging at 1 year after surgery.

RESULTS

Overall, only three patients (8.3%) had serum vitamin D sufficiency (>20 ng/mL). Among 36 patients, 26 patients returned for their 1-year follow-up. Lower preoperative serum vitamin D levels resulted in lower serum vitamin D levels at 6 months and 1 year postoperatively (all P < .05). Lower preoperative and 1-year postoperative serum vitamin D levels resulted in more torque deficiency on the IMPT in abduction than higher preoperative and 1-year postoperative serum vitamin D levels (all P < .05). Tissue vitamin D levels had a strong correlation with preoperative serum vitamin D levels (P = .001). Lower tissue vitamin D levels were associated with lower peak torque on the IMPT in abduction (P = .043) and a tendency of lower peak torque on the IMPT in external rotation (P = .077) at 1 year postoperatively. There was no correlation between tissue and serum vitamin D levels and functional outcomes, fatty degeneration, and healing failure after surgery (all P > .05). The vitamin D receptor showed no correlation with any variables (all P > .05).

CONCLUSION

Lower preoperative serum vitamin D levels had a strong correlation with lower tissue vitamin D levels and lower serum vitamin D levels at 1 year after surgery. Furthermore, the patients with lower serum vitamin D levels showed more weakness of muscle power perioperatively. The results of this study emphasized the association between vitamin D levels and rotator cuff muscle power.

Vitamin D Deficiency in Both Oral and Systemic Manifestations in SARS-CoV-2 Infection: Updated Review

The specialized literature emphasizes the fact that vitamin D has a potentially beneficial effect in the context of the current COVID-19 pandemic. The purpose of this article is to highlight the role of vitamin D, both prophylactic and curative, in the treatment of patients diagnosed with COVID-19. Even though its relevance is still unknown and causes various controversies, there is currently no specific treatment for patients diagnosed with COVID-19. There are various prevention strategies with new vaccination schedules, but additional randomized and clinical trials are still needed to combat this pandemic. In addition to the systemic manifestations of SARS-CoV-2 infection, oral manifestations of this disease have also been described in the literature. The etiology of oral manifestations associated with COVID-19 infection and vitamin D deficiency remains controversial. In the present studies, oral manifestations such as salivary gland infections, aphthae, erythema, gingivitis, ulcers, etc. have been reported. This is a new topic, and the prevalence of manifestations is described in only a few studies, which is inconsistent with the number of COVID-19 cases reported since the beginning of the pandemic. The clinical symptomatology in patients with current COVID-19 infection is polymorphic. Whether the oral manifestation is directly caused by SARS-CoV-2 or a secondary manifestation remains an important topic to analyze and discuss.

Vitamin D Metabolic Pathway Components in Orthopedic Patientes-Systematic Review

Vitamin D takes part in the functioning of many processes that ensure the homeostasis of the body. In orthopedics, it is indicated as an inseparable element ensuring proper bone growth and functioning, and its deficiencies are indicated in various diseases, mainly in the proper structure and function of the skeleton. In this review, we focus on the most important components of the vitamin D metabolic pathway, in correlation with selected orthopedic conditions. Records were obtained from the PubMed database in a timeline of 2010-2022. The keywords were as follows: vitamin D/cholesterol/vitamin D binding protein/ VDBP/Cytochrome/CYP24A1/CYP 27B1/Vitamin D receptor/VDR/ + diseases (ACL reconstruction, rotator cuff, arthroplasty knee/hip/shoulder). The recent original studies were analyzed, discussed, and the most important data were shown. The vast majority of articles concern the metabolite of vitamin D (25(OH)D), which is measured as a standard in diagnostic laboratories. Even though there is a lot of valuable information in the literature, we believe that the other elements of the vitamin D pathway also deserve attention and suggest their research in correlation with orthopedic disorders to supplement the missing knowledge on this topic.

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.

Vitamin D, exercise, and immune health in athletes: A narrative review

Vitamin D exerts important extra-skeletal effects, exhibiting an exquisite immune regulatory ability, affecting both innate and adaptive immune responses through the modulation of immunocyte function and signaling. Remarkably, the immune function of working skeletal muscle, which is fully recognized to behave as a secretory organ with immune capacity, is under the tight control of vitamin D as well. Vitamin D status, meaning hormone sufficiency or insufficiency, can push toward strengthening/stabilization or decline of immune surveillance, with important consequences for health. This aspect is particularly relevant when considering the athletic population: while exercising is, nowadays, the recommended approach to maintain health and counteract inflammatory processes, “too much” exercise, often experienced by athletes, can increase inflammation, decrease immune surveillance, and expose them to a higher risk of diseases. When overexercise intersects with hypovitaminosis D, the overall effects on the immune system might converge into immune depression and higher vulnerability to diseases. This paper aims to provide an overview of how vitamin D shapes human immune responses, acting on the immune system and skeletal muscle cells; some aspects of exercise-related immune modifications are addressed, focusing on athletes. The crossroad where vitamin D and exercise meet can profile whole-body immune response and health.

Pharmacologic Enhancement of Rotator Cuff Repair: A Narrative Review

INTRODUCTION

As rotator cuff repairs (RCRs) are among the most common procedures in upper extremity orthopedics, healing augmentation using pharmacologic enhancement of the repaired rotator cuff muscle is of particular interest.

OBJECTIVE

The purpose of this study is to review the current understanding of Matrix Metalloproteinases (MMPs), Doxycycline, Testosterone, Estrogen, Growth hormone/ IGF-1, Vitamin D, and Vitamin C as a means to mitigate deleterious effects and propagate factors that support healing following RCR.

METHODS

A review of English language articles in PubMed and Medline was conducted in December of 2020. All articles describing the current understanding of the aforementioned therapies were reviewed. Studies were excluded if they were non-English or reported incomplete results.

RESULTS

Matrix metalloproteinases (MMP's) are fundamental to the healing process after rotator cuff tears through a delicate balance of various proteases that can be modulated by doxycycline through inhibition. While testosterone has shown to induce replication and differentiation of the tendon stem-cells, estrogen agonists have been shown to decrease inflammation and muscle atrophy. Though growth hormone being associated with elevated collagen synthesis and decreased anoxic damage when present, clinical studies have shown inconclusive and adverse effects on rotator cuff healing. Patients with Vitamin D deficiency have shown to have increased fatty infiltration in rotator cuff muscle while Vitamin C functions as an antioxidant that increases collagen and fibroblast proliferation.

CONCLUSION

As manipulation of pharmacologic factors shows potential for enhancing healing following RCRs, future studies are needed to establish a viable augmentation strategy to improve patient outcomes.

The Prevalence of Vitamin D Deficiency in Patients Undergoing Total Knee Arthroplasty: A Propensity Score Matching Analysis

PURPOSE

We investigated and compared the serum 25-OH vitamin D [25(OH)D] level and prevalence of vitamin D deficiency (VDD) between patients who underwent total knee arthroplasty (TKA) and healthy participants through a matched analysis.

METHODS

The unmatched case group consisted of 824 patients who underwent TKA and the unmatched control group 2,794 healthy participants examined at our institution. The control group was matched on the various characteristics-sex, age, weight, body mass index (BMI), blood chemistry, and season of sampling-through propensity score matching (PSM). After PSM, 501 and 721 patients were matched in the case and control group, respectively. Levels of blood chemistry including 25(OH)D were examined and VDD was defined as < 20 ng/mL.

RESULTS

The average serum 25(OH)D level was significantly lower in the OA group (15.3 ng/mL) than that in the control group (19.9 ng/mL, p < 0.001). When categorized using a 20 ng/mL cutoff, the VDD prevalence was 75.0% in the OA group and 59.4% in the control group. The prevalence of vitamin D insufficiency was 18.4% in the OA group and 24.5% in the control group. The prevalence of vitamin D sufficiency was 6.8% in the OA group and 15.9% in the control group (p < 0.001).

CONCLUSIONS

The patients who underwent TKA had lower serum 25(OH)D level and higher VDD prevalence compared to the healthy participants who matched using PSM. There were no differences in VDD rates by sex or obesity and the VDD prevalence was more than 70% during all season. Therefore, in patients undergoing TKA, general attention to VDD is required regardless of sex, obesity, and season. Serum 25-OH vitamin D [25(OH)D] level and vitamin D deficiency (VDD) prevalence were compared between patients undergoing total knee arthroplasty and healthy individuals. The differences in serum 25(OH)D level and VDD prevalence were significant between the two groups after propensity score matching.

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.

Sarcopenia; functional concerns, molecular mechanisms involved, and seafood as a nutritional intervention - review article

The fundamental basis for the human function is provided by skeletal muscle. Advancing age causes selective fiber atrophy, motor unit loss, and hybrid fiber formation resulting in hampered mass and strength, thus referred to as sarcopenia. Influence on the loss of independence of aged adults, contribute toward inclined healthcare costs conveys the injurious impact. The current understating of age-related skeletal muscle changes are addressed in this review, and further discusses mechanisms regulating protein turnover, although they do not completely define the process yet. Moreover, the reduced capacity of muscle regeneration due to impairment of satellite cell activation and proliferation with neuronal, immunological, hormonal factors were brought into the light of attention. Nevertheless, complete understating of sarcopenia requires disentangling it from disuse and disease. Nutritional intervention is considered a potentially preventable factor contributing to sarcopenia. Seafood is a crucial player in the fight against hunger and malnutrition, where it consists of macro and micronutrients. Hence, the review shed light on seafood as a nutritional intrusion in the treatment and prevention of sarcopenia. Understanding multiple factors will provide therapeutic targets in the prevention, treatment, and overcoming adverse effects of sarcopenia.

The role of vitamin D and vitamin D deficiency in orthopaedics and traumatology-a narrative overview of the literature

Vitamin D is considered to play an important role in musculoskeletal health. It’s classical function is the regulation of calcium and phosphate homeostasis, thus ensuring a balanced bone metabolism that is characterised by an equal amount of bone resorption and bone formation. In the past decades, a plethora of pre-clinical and clinical studies reporting on potential health-beneficial properties of vitamin D have emerged. Moreover, there is an abundance of reports highlighting vitamin D deficiency and insufficiency in patients with almost innumerable diseases. Further, it is estimated that more than one billion people globally are affected by insufficient vitamin D levels. As such, research on vitamin D has been particularly popular over the past years. In orthopaedics and traumatology, most studies describe favourable effects of vitamin D in general. However, the relative importance of vitamin D is oftentimes debated. In this narrative review of the literature, we consider first, the properties of vitamin D and how vitamin D, vitamin D deficiency and the vitamin D receptor (VDR) impact on musculoskeletal health. Secondly, we provide an overview of studies reporting the prevalence of vitamin D deficiency in traumatology and diverse orthopaedic diseases including bone oncology. Lastly, we emphasise recent findings and touch on future perspectives in vitamin D research.

[Musculoskeletal laboratory diagnostics in competitive sport]

Hintergrund

Die labordiagnostische Untersuchung stellt eine wichtige Möglichkeit zur Beurteilung und Optimierung der Leistungs- und Regenerationsfähigkeit professioneller Athleten dar. Ferner ist sie für die Prävention, Diagnostik und Rehabilitation von Verletzungen und Überbelastungen von Bedeutung.

Fragestellung

Ziel dieser Arbeit ist die Darstellung muskuloskelettaler laborchemischer Parameter, die relevante Erkenntnisse für die medizinische Betreuung von Leistungssportlern liefern.

Material und Methoden

Literaturrecherche und narratives Review.

Ergebnisse

Die Bestimmung des Vitamin-D-, Calcium- und Knochenstoffwechsels stellt die laborchemische Basisdiagnostik im Rahmen der Beurteilung des Skelettstatus mit zusätzlichem präventivem Nutzen bezüglich muskuloskelettaler Verletzungen dar. Ferner können muskuläre Serummarker, z. B. Laktatdehydrogenase (LDH), Kreatinkinase (CK), Myoglobin und Aspartat-Aminotransferase (ASAT), helfen, eine metabolische Adaptation an das physische Training festzustellen und Aussagen über die muskuläre Arbeitslast und mögliche Schädigungen zu gewinnen. Die Energieverfügbarkeit kann durch eine entsprechende Bilanzierung sowie die laborchemische Bestimmung der Makro- und Mikronährstoffe eingeschätzt und optimiert werden.

Schlussfolgerungen

Die labordiagnostische Untersuchung besitzt in der Betreuung von Athleten eine sportartenübergreifende klinische Relevanz. Sie dient der Erreichung einer höchstmöglichen Leistungsfähigkeit sowie optimalen Prävention von Knochen- und Muskelverletzungen, wobei sämtliche Mangelzustände (z. B. Vitamin D) ausgeglichen werden sollten. Durch eine Periodisierung der laborchemischen Untersuchungen, mit zumindest zwei Labordiagnostiken im Jahr, und Aufstellung individueller Variabilitäts- und Referenzbereiche kann ferner eine bessere Beurteilbarkeit erreicht werden.

Vitamin D deficiency and total shoulder arthroplasty complications

INTRODUCTION

The primary objective of this study was to examine the relationship between vitamin D deficiency and implant-related and medical complications following total shoulder arthroplasty.

METHODS

Using the PearlDiver database, patients who underwent total shoulder arthroplasty from 2005 to 2016 with vitamin D deficiency were identified. These were compared to a 3:1 control group matched by age, sex, and presence of a concomitant osteoporosis diagnosis. Primary outcome measures were implant-related complications (loosening, periprosthetic fracture, periprosthetic joint infection, and revision total shoulder arthroplasty) in addition to medical complications within 90 days of surgery. A multivariable logistic regression analysis was utilized to control for patient demographics and comorbidities.

RESULTS

One thousand and six hundred and seventy-four patients with vitamin D deficiency were identified and compared to 5022 controls. There was a significantly higher rate of revision total shoulder arthroplasty in the vitamin D deficient patients compared to controls (2.3% versus 0.8%, odds ratio 3.3, p < 0.0001). After controlling for confounding variables, there were no significant differences in any of the remaining implant-related or medical complications with the exception of higher rates of urinary tract infections in patients with vitamin D deficiency.

CONCLUSIONS

Vitamin D deficiency is associated with a higher rate of all-cause revision total shoulder arthroplasty but not medical complications compared to controls.Level of evidence: Level III case control study.

The role of vitamin D in primary and secondary prevention in orthopaedic patients

The article discusses the effect of vitamin D on primary and secondary prevention of fractures and its effect on conditions after selected orthopaedic procedures. Fractures can be divided into traumatic, fatigue and pathological according to the cause. One of the complications of fracture is the formation of a nonunion. In addition to dealing with fractures, a total joint replacement is another common procedure in orthopaedic surgery. Because insufficient muscle strength can increase the risk of falls and thus result in a fracture, these topics are also mentioned in this article. Due to the impact of vitamin D deficiency on various musculoskeletal disorders, orthopaedic surgeons should pay more attention to the patients vitamin D status and be familiar with different strategies for preventing hypovitaminosis D, although clear evidence-based medical recommendations are still insufficient.

Prevalence of and Risk Factors for Hypovitaminosis D in Patients with Rotator Cuff Tears

Backgroud

It has been reported that vitamin D may play an important role in rotator cuff tears. However, there has been limited information about the prevalence of and risk factors for hypovitaminosis D in patients with rotator cuff tears. Therefore, the purpose of current study was to investigate the prevalence of and risk factors for hypovitaminosis D in patients with rotator cuff tears.

Methods

One hundred seventy-six patients (age, 61.9 ± 8.90 years) who underwent arthroscopic rotator cuff repair for a full-thickness tear were enrolled in this retrospective study. Preoperative serum vitamin D levels (25-hydroxyvitamin D) were measured. Hypovitaminosis D was defined as a serum concentration of 25-hydroxyvitamin D < 20 ng/mL. We investigated whether age, sex, height, weight, body mass index, bone mineral density, alcohol consumption, smoking status, and outdoor occupation were associated with hypovitaminosis D.

Results

The prevalence of hypovitaminosis D in patients with rotator cuff tears was 44.3% (78/176). The mean serum concentration of 25-hydroxyvitamin D of total patients was 24.7 ± 13.7 ng/mL. A higher serum level of vitamin D was significantly associated with older age (p < 0.001). Young age was an independent risk factor for hypovitaminosis D. The prevalence of hypovitaminosis D was also lower in patients with an outdoor occupation than in those with an indoor occupation (19.0% vs. 31.4%, p = 0.001).

Conclusions

The prevalence of hypovitaminosis D in patients with rotator cuff tears was 44.3%. Age had a significant positive correlation with the serum concentration of 25-hydroxyvitamin D. Young age and indoor working were independent risk factors for hypovitaminosis D in patients with rotator cuff tears. Therefore, the possibility of hypovitaminosis D should be considered for young and indoor working patients who have rotator cuff tears.

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.

Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends

We are currently experiencing a vitamin D (VITD) deficiency pandemic across the world. Athletes have the same predisposition to low levels of vitamin D, the majority of its concentrations being below 20 ng/mL in a wide range of sports, especially in the winter months. Vitamin D is important in bone health, but recent research also points out its essential role in extraskeletal functions, including skeletal muscle growth, immune and cardiopulmonary functions and inflammatory modulation, which influence athletic performance. Vitamin D can also interact with extraskeletal tissues to modulate injury recovery and also influence the risk of infection. The data presented in this paper has triggered investigations in relation to the importance of maintaining adequate levels of vitamin D and to the possible positive influence supplementation has on immune and musculoskeletal functions in athletes, benefiting their performance and preventing future injuries. The objective of this review is to describe the latest research conducted on the epidemiology of vitamin D deficiency and its effects on sports performance and musculoskeletal health.

Novel Insights on Intake of Fish and Prevention of Sarcopenia: All Reasons for an Adequate Consumption

Sarcopenia is defined as a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength and it is diagnosed by measurements of muscle mass, muscle strength, and physical performance. Sarcopenia affects quality of life and is associated with several adverse health effects. Muscle decline is aggravated by a sedentary lifestyle and can be prevented through proper nutrition, together with adequate physical activity. Fish contains biologically active compounds, such as omega-3 polyunsaturated fatty acids, proteins, vitamin D, magnesium, and carnitine, which are able to intervene positively on muscle metabolism. This narrative literature review was performed to evaluate evidence regarding the actual benefit of fish consumption in the prevention of sarcopenia and the positive action on the muscle mass of the biological compounds present in fish. The results demonstrated that fish consumption has a protective and anti-inflammatory function on skeletal muscle and that its biologically active compounds help to maintain good muscle performance, preventing sarcopenia. Considering the nutritional and health benefits, elderly with sarcopenia should consume at least three servings per week of fish in order to have a minimum intake of 4-4.59 g daily of omega 3, and reaching the 50% RDA in Vitamin E and D. High biological value of proteins in 150 g of fish and its high available magnesium (20% of RDA in 150 g of fish) are an added value that could suggest fish as a "functional food" in order to prevent and treat sarcopenia.

Restoration of Cellular Proliferation and Characteristics of Human Tenocytes by Vitamin D

Vitamin D (Vit D) increases calcium absorption in the intestine after binding to the Vit D receptor (VDR). The VDR has also been identified in muscle cells. Vit D supplementation resulted in improved muscle strength. However, there is a paucity of studies of the role of Vit D on tenocytes. We investigated the effects of Vit D on damaged tenocytes. Human tenocytes were treated with dexamethasone (Dex) to induce cell injury. Expression of the tenocyte-related markers tenomodulin (Tnmd), tenascin C (Tnc), scleraxis (Scx), mohawk (Mkx), and collagen (Col) 1 and 3 were measured. Then, tenocytes were cotreated with Vit D. 1-α-Hydroxylase and VDR were explored in tenocytes. With 10 μM Dex, the growth of tenocytes was significantly inhibited, and the gene expression of Tnmd, Tnc, Scx, Mkx, Col 1 and 3 also decreased. When tenocytes were cotreated with Vit D, cell proliferation recovered in a dose-dependent manner, and the expression of TNMD and Col 1 improved. When studying the mechanisms of the effects of Vit D on tenocytes, reactive oxygen species produced by Dex decreased with Vit D, and the phosphorylation of extracellular signal-regulated kinase and p38 was stimulated by Vit D cotreatment. 1-α-Hydroxylase and VDR were found in tenocytes, indicating that the cells have the ability to use an inactive form of Vit D and interact with it. Vit D is known to perform diverse actions and its protective effects on tenocytes suggest its beneficial role in tendon in addition to muscle and bone. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2241-2248, 2019.

Is There a Correlation Between Preoperative or Postoperative Vitamin D Levels with Pseudarthrosis, Hardware Failure, and Revisions After Lumbar Spine Fusion?

BACKGROUND

Vitamin D deficiency is a well-known cause of postoperative complications in patients undergoing orthopedic surgery. Orthopedic complications seen in vitamin D deficiency include nonunion, pseudarthrosis, and hardware failure. We seek to investigate the relationship between vitamin D deficiency and outcomes after lumbar spinal fusions.

METHODS

A retrospective patient chart review was conducted at a single center for all patients who underwent lumbar spinal fusions from January 2015 to September 2017 with preoperative or postoperative vitamin D laboratory values. We recorded demographics, social history, medications, pre-existing medical conditions, bone density (dual-energy x-ray absorptiometry) T-scores, procedural details, 1-year postoperative Visual Analog Score (VAS), documented pseudarthrosis, revisions, and hardware failure. A total of 150 patients were initially included in the cohort for analysis.

RESULTS

Overall, preoperative and postoperative vitamin D levels were not significantly associated with a vast majority of the patient characteristics studied, including comorbidities, medications, or surgical diagnoses (P > 0.05). Age at surgery was significantly associated with vitamin D levels; older patients had higher serum levels of vitamin D both preoperatively (P = 0.03) and postoperatively (P = 0.01). Those with a higher average body mass index had lower vitamin D in both groups (P = 0.02). Vitamin D levels were not significantly associated with rates of postoperative pseudarthrosis, revision, or hardware complications (P > 0.05). VAS pain score at 1 year and smoking status preoperatively or postoperatively were not associated with vitamin D levels (P > 0.05).

CONCLUSIONS

Both preoperative and postoperative vitamin D levels were not significantly associated with an increased or decreased risk of pseudarthrosis, revision surgery, hardware failure, or 1-year VAS pain score after lumbar spine fusion surgery.

Surgical Considerations in Managing Osteoporosis, Osteopenia, and Vitamin D Deficiency During Arthroscopic Rotator Cuff Repair

Osteopenia and osteoporosis are common in older adults and are associated with increased risk of fragility fractures. Vitamin D deficiency caused by chronic disease, poor nutrition, and inadequate sun exposure affects bone quality. Chronic rotator cuff tears can deteriorate the bone mineral density of the greater tuberosity and have been linked to reduced anchor pullout strength and high re-tear rate after repair especially in older patients with larger tear size. This article summarizes the current evidence on rotator cuff tear and bone quality and provides treatment strategies for rotator cuff repair in patients with poor bone quality.

Current concepts in vitamin D and orthopaedic surgery

INTRODUCTION

Vitamin D plays an important role in the musculoskeletal system of the human body. Here, we review the most current literature on vitamin D as it relates to orthopaedic surgery and the musculoskeletal system, focusing largely on non-fracture applications.

MATERIALS AND METHODS

A literature review was performed on the basic science of vitamin D metabolism, epidemiology of vitamin D levels, role of vitamin D within the musculoskeletal system, and the correlation of vitamin D with injuries and orthopaedic surgical outcomes.

RESULTS

The existing literature suggests vitamin D plays multiple roles in the musculoskeletal system. Recent research has shed light on the importance of vitamin D in the setting of soft tissue healing and recovery in addition to affecting postoperative outcomes after common orthopaedic procedures.

CONCLUSIONS

Given the widespread prevalence of vitamin D deficiency, orthopaedic surgeons should be aware of the current evidence regarding clinical implications in patients with musculoskeletal complaints.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Effect of Abnormal Vitamin D Levels in Athletes

Vitamin D is a lipophilic prohormone integral to musculoskeletal, autoimmune, oncologic, cardiovascular, and mental health. Of particular importance to the orthopedic surgeon is the role of vitamin D in the regulation of bone mass, muscle strength, and physical performance. Although vitamin D-related skeletal pathologies are rare in industrialized nations, emerging research in the field has shown that most American adults have inadequate levels of vitamin D. Even among athletes, there is a high prevalence of vitamin D deficiency, which may place competitors at risk of stress fractures, illness, and delayed muscle recovery. Adequately identifying vitamin D-deficient individuals in need of supplementation is important to help optimize performance and prevent future injury. The goal of this review is to describe the epidemiology of vitamin D deficiency and its effects on athletic performance and musculoskeletal health. Future double-blinded studies of vitamin D supplementation in athletes are needed. We recommend treating athletes who have insufficient or deficient vitamin D levels.

Effect of recombinant human growth hormone on rotator cuff healing after arthroscopic repair: preliminary result of a multicenter, prospective, randomized, open-label blinded end point clinical exploratory trial

BACKGROUND

This study evaluated the effect of systemic injection of recombinant human growth hormone (rhGH) on outcomes after arthroscopic rotator cuff repair.

METHODS

This multicenter, prospective, randomized, comparative trial, randomized patients who underwent arthroscopic repair of large-sized rotator cuff tears into 3 groups: rhGH 4 mg group (n = 26), rhGH 8 mg group (n = 24) , and control group (n = 26). Sustained release rhGH was injected subcutaneously once weekly for 3 months postoperatively. The healing failure rate (primary end point), fatty infiltration, and atrophy of the supraspinatus muscle, and functional scores (Constant and American Shoulder and Elbow Surgeons scores) were evaluated at 6 months. Range of motion, pain visual analog scale, and serum insulin-like growth factor-1 level were measured at each follow-up.

RESULTS

The healing failure rate was similar between groups (rhGH 4 mg group, 30.8%; rhGH 8 mg group, 16.7%; and control group, 34.6%; all P > .05) The proportion of severe fatty infiltration (Goutallier grade ≥3) was 20.8% in the rhGH 8 mg group, 23.1% in the rhGH 4 mg group, and 34.6% in the control group (P > .05). Functional outcomes, range of motion, and pain visual analog scale were similar between groups (all P > .05). The rhGH 8 mg group showed more increased peak insulin-like growth factor-1 level (279.43 ng/mL) than the rhGH 4 mg group ((196.82 ng/mL) and control group (186.31 ng/mL), which was not statistically different (all P > .05). No rhGH injection-related major safety issues occurred.

CONCLUSIONS

This preliminary study showed no statistically significant improvement in healing or outcomes related to the treatment of rhGH after rotator cuff repair. However, further study with more enrolled patients after resetting the rhGH dose or daily administration protocol would be mandatory.

Effect of Vitamin D Deficiency on Voice

PURPOSE

The purpose of this article was to investigate the relationship between low level of vitamin D, phonatory symptoms, and acoustic findings.

METHOD

A total of 38 subjects presenting to the endocrinology clinic were enrolled in 2 groups: 19 with vitamin D deficiency who were not on treatment, and 19 with normal vitamin D level who were on treatment. Demographic data included age, gender, and history of smoking. All patients were asked about the presence or absence of dysphonia, degree of phonatory effort, and vocal fatigue. Acoustic analysis and perceptual evaluation using the grade, roughness, breathiness, asthenia, and strain scale were performed on all subjects.

RESULTS

The mean age of the total group was 47.29 ± 13.52 years. The difference in the mean and frequency of phonatory effort, vocal fatigue, and dysphonia, and in the mean of the acoustic variables, perceptual parameters, and the score of the Voice Handicap Index-10 was not statistically significant between patients with low vitamin D levels compared with controls.

CONCLUSION

The results of this study revealed no significant difference in the prevalence of phonatory symptoms in patients with vitamin D deficiency compared with patients with no vitamin D deficiency. A larger study is needed to substantiate the difference in the prevalence of phonatory systems between the 2 groups.

Improvement of fatigue after vitamin D supplementation in kidney transplant recipients

Low serum levels of vitamin D have been associated with fatigue in both healthy and clinical populations. Our aim was to evaluate the effect of vitamin D supplementation on fatigue in kidney transplant recipients (KTRs). In total, 137 patients after kidney transplant and 119 age- and sex-matched healthy volunteers were recruited. Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured by competitive protein-binding assay. Fatigue was assessed using the subscale fatigue of the Checklist Individual Strength (CIS). Of all KTRs, 60 patients without initial vitamin D3 supplementation were started on vitamin D3 supplementation (cholecalciferol) 800 IU/d, with a follow-up examination after 3.0 to 9.0 months (mean, 6 months). Fatigue was found in 40.1% of KTRs. Serum 25(OH)D levels were inversely and independently associated with CIS scores in KTRs (P = .002). In the 60 patients who received vitamin D3 supplementation, 25(OH)D was overall increased at follow-up with 18.5% (P = .004) and CIS scores improved with 10.0% (P = .007). As vitamin D has beneficial effects on fatigue scores in KTRs, we suggest monitoring this parameter in KTRs and supplementation with vitamin D3 when vitamin D levels are low.

The biology of rotator cuff healing

Despite advances in surgical reconstruction of chronic rotator cuff (RC) tears leading to improved clinical outcomes, failure rates of 13-94% have been reported. Reasons for this rather high failure rate include compromised healing at the bone-tendon interface, as well as the musculo-tendinous changes that occur after RC tears, namely retraction and muscle atrophy, as well as fatty infiltration. Significant research efforts have focused on gaining a better understanding of these pathological changes in order to design effective therapeutic solutions. Biological augmentation, including the application of different growth factors, platelet concentrates, cells, scaffolds and various drugs, or a combination of the above have been studied. It is important to note that instead of a physiological enthesis, an abundance of scar tissue is formed. Even though cytokines have demonstrated the potential to improve rotator cuff healing in animal models, there is little information about the correct concentration and timing of the more than 1500 cytokines that interact during the healing process. There is only minimal evidence that platelet concentrates may lead to improvement in radiographic, but not clinical outcome. Using stem cells to biologically augment the reconstruction of the tears might have a great potential since these cells can differentiate into various cell types that are integral for healing. However, further studies are necessary to understand how to enhance the potential of these stem cells in a safe and efficient way. This article intends to give an overview of the biological augmentation options found in the literature.

Mendelian Randomization Studies Do Not Support a Role for Vitamin D in Coronary Artery Disease

BACKGROUND

Observational studies support a possible association between decreased vitamin D levels and risk of coronary artery disease (CAD); however, it remains unclear whether this relationship is causal. We aimed to evaluate whether genetically lowered vitamin D levels influence the risk of CAD using a Mendelian randomization approach.

METHODS AND RESULTS

In this 2-stage Mendelian randomization study, we first identified single-nucleotide polymorphisms associated with 25-hydroxyvitamin D (25OHD) levels in the SUNLIGHT consortium (n=33 996), then tested them for possible violation of Mendelian randomization assumptions. A count of risk alleles was tested for association with 25OHD levels in a separate cohort (n=2347). Alleles were weighted by their relative effect on 25OHD and tested for their combined effect on CAD in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) study (22 233 cases/64 762 controls). Four single-nucleotide polymorphisms were identified to be associated with 25OHD levels, all in or near genes implicated in 25OHD synthesis, transport or metabolism. A count of these risk alleles was strongly associated with 25OHD (n=2347, F-test statistic=49.7, P=2×10(-12)). None of the single-nucleotide polymorphisms associated with 25OHD levels were associated with CAD (all P values >0.6). The Mendelian randomization odds ratio (OR) for CAD was 0.99 (95% confidence interval, 0.84-1.17; P=0.93; I(2)=0) per SD decrease in log-transformed 25OHD levels. These results persisted after sensitivity analyses for population stratification and pleiotropy.

CONCLUSIONS

Genetically lowered 25OHD levels were not associated with increased risk of CAD in a large, well-powered study, suggesting that previous associations between circulating 25OHD levels and CAD are possibly confounded or due to reverse causation.

Vitamin D and the immunomodulation of rotator cuff injury

Tendon-to-bone healing after rotator cuff repair surgery has a failure rate of 20%–94%. There has been a recent interest to determine the factors that act as determinants between successful and unsuccessful rotator cuff repair. Vitamin D level in patients is one of the factors that have been linked to bone and muscle proliferation and healing, and it may have an effect on tendon-to-bone healing. The purpose of this article is to critically review relevant published research that relates to the effect of vitamin D on rotator cuff tears and subsequent healing. A review of the literature was conducted to identify all studies that investigate the relationship between vitamin D and tendon healing, in addition to its mechanism of action. The data were then analyzed in order to summarize what is currently known about vitamin D, rotator cuff pathology, and tendon-to-bone healing. The activated metabolite of vitamin D, 1α,25-dihydroxyvitamin D₃, affects osteoblast proliferation and differentiation. Likewise, vitamin D plays a significant role in the tendon-to-bone healing process by increasing the bone mineral density and strengthening the skeletal muscles. The 1α,25-dihydroxyvitamin D₃ binds to vitamin D receptors on myocytes to stimulate growth and proliferation. The form of vitamin D produced by the liver, calcifediol, is a key initiator of the myocyte healing process by moving phosphate into myocytes, which improves function and metabolism. Investigation into the effect of vitamin D on tendons has been sparse, but limited studies have been promising. Matrix metalloproteinases play an active role in remodeling the extracellular matrix (ECM) of tendons, particularly deleterious remodeling of the collagen fibers. Also, the levels of transforming growth factor-β3 positively influence the success of the surgery for rotator cuff repair. In the tendon-to-bone healing process, vitamin D has been shown to successfully influence bone and muscle healing, but more research is needed to delve into the mechanisms of vitamin D as a factor in skeletal tendon health and healing.

Correlation between vitamin D levels and muscle fatigue risk factors based on physical activity in healthy older adults

PURPOSE

The purpose of this study was to investigate the relationship of serum vitamin D levels with physical activity, obesity, muscle fatigue biomarkers, and total antioxidant capacity (TAC) in healthy older adults.

METHODS

A total of 85 healthy older subjects aged 64-96 years were recruited in this study. Based on estimated energy expenditure scores, the participants were classified into three groups: inactive (n=25), moderate (n=20), and physically active (n=35). Serum 25(OH)D (25-hydroxy vitamin D) levels, metabolic syndrome parameters, TAC activity, muscle fatigue biomarkers (Ca, creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline), physical activity, body fatness, and fatigue score (visual analog scale) were estimated using immunoassay techniques and prevalidated questionnaires, respectively.

RESULTS

Physical activity was estimated in 64.6% of the participants. Males showed higher physical activity (42.5%) compared to females (26.25%). Compared to participants with lower activity, significant reduction in body mass index, waist circumference, hips, fasting blood sugar, triglycerides, total cholesterol, HDL-cholesterol, and LDL-cholesterol were observed in moderate and physically active participants. Also, significant increase in the levels of serum 25(OH)D concentrations, calcium, and TAC activity along with reduction in the levels of muscle fatigue biomarkers: creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline, and fatigue scores (visual analog scale) were reported in physically active participants compared to those of lower physical activity. In all participants, serum 25(OH)D concentrations correlated positively with Ca, TAC, physical activity scores, and negatively with body mass index, lipid profile, fatigue scores (visual analog scale), and muscle fatigue biomarkers. Stepwise regression analysis showed that serum 25(OH)D concentrations, physical activity, Ca, TAC, and demographic parameters explained approximately 61.4%-85.8% of reduction in both fatigue scores and muscle fatigue biomarkers with substantial improvement in muscle performance in healthy older adults.

CONCLUSION

The data showed that considerable levels of 25(OH)D concentrations, calcium intake, and lower obesity positively correlated with the improvement in the muscle relief and performance of physically active participants. These results demonstrate that 25(OH)D concentrations and calcium might prevent muscle fatigue by regulation of the biosynthesis of creatine kinase, lactic acid dehydrogenase, troponin I, and hydroxyproline via a proposed antifree radical mechanism reported by higher TAC activity. It was suggested that vitamin D status could be reported as a marker of the improvement of muscle performance, especially in healthy older adults with lower physical activity.

Effect of Hypercholesterolemia on Fatty Infiltration and Quality of Tendon-to-Bone Healing in a Rabbit Model of a Chronic Rotator Cuff Tear: Electrophysiological, Biomechanical, and Histological Analyses

BACKGROUND

The incidence of healing failure after rotator cuff repair is high, and fatty infiltration is a crucial factor in healing failure.

PURPOSE

To verify the effect of hypercholesterolemia on fatty infiltration and the quality of tendon-to-bone healing and its reversibility by lowering the cholesterol level in a chronic tear model using the rabbit supraspinatus.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-eight rabbits were randomly allocated into 4 groups (n = 12 each). After 4 weeks of a high-cholesterol diet (groups A and B) and a regular diet (groups C and D), the supraspinatus tendon was detached and left alone for 6 weeks and then was repaired in a transosseous manner (groups A, B, and C). Group D served as a control. Group A continued to receive the high-cholesterol diet until the final evaluation (6 weeks after repair); however, at the time of repair, group B was changed to a general diet with administration of a cholesterol-lowering agent (simvastatin). Histological evaluation of the fat-to-muscle proportion was performed twice, at the time of repair and the final evaluation, and an electromyographic (EMG) test, mechanical test, and histological test of tendon-to-bone healing were performed at the final evaluation.

RESULTS

For the EMG test, group A showed a significantly smaller area of compound muscle action potential compared with groups C and D (all P <.01), and group B showed a larger area than group A, almost up to the level of group C (P = .312). Similarly, group A showed significantly lower mechanical properties both in load-to-failure and stiffness compared with groups C and D (all P <.05). In addition, although not significantly different, the mechanical properties of group B were higher than those of group A (mean load-to-failure: group A = 42.01 N, group B = 58.23 N [P = .103]; mean stiffness: group A = 36.32 N/mm, group B = 47.22 N/mm [P = .153]). For the histological test, groups A and B showed a significantly higher fat-to-muscle proportion than did groups C and D at 6 weeks after detachment (all P <.05), but at the final evaluation, group B showed a decreased fat-to-muscle proportion (mean ± SD: from 64.02% ± 11.87% to 54.68% ± 10.47%; P = .146) compared with group A, which showed increased fat-to-muscle proportion (from 59.26% ± 17.80% to 78.23% ± 10.87%; P = .015). Groups B and C showed better tendon-to-bone interface structures than did group A, which showed coarse and poorly organized collagen fibers with fat interposition.

CONCLUSION

Hypercholesterolemia had a deleterious effect on fatty infiltration and the quality of tendon-to-bone repair site, and lowering hypercholesterolemia seemed to halt or reverse these harmful effects in this experimental model.

CLINICAL RELEVANCE

Systemic diseases such as hypercholesterolemia should be tightly controlled during the perioperative period of rotator cuff repair.

Anabolic Steroids Reduce Muscle Degeneration Associated With Rotator Cuff Tendon Release in Sheep

BACKGROUND

Chronic rotator cuff tendon tearing is associated with irreversible atrophy, fatty infiltration, and interstitial fibrosis of the corresponding muscle.

HYPOTHESES

Anabolic steroids can prevent musculotendinous degeneration during retraction and/or can reverse these changes after operative repair of the retracted musculotendinous unit in sheep.

STUDY DESIGN

Controlled laboratory study.

METHODS

The infraspinatus tendon was released in 18 alpine sheep. All sheep underwent repair of the retracted musculotendinous unit after 16 weeks and were sacrificed after 22 weeks; 6 sheep served as controls, 6 sheep were treated with weekly intramuscular injection of 150 mg of nandrolone decanoate after infraspinatus (ISP) repair (group N6W), and 6 sheep were treated with 150 mg of nandrolone decanoate immediately after tendon release (group N22W). Muscle biopsy specimens were taken before tendon release and after 16 and 22 weeks. Muscle volume and fatty infiltration (on MRI), myotendinous retraction, and muscle density (on computed tomography) were measured immediately after ISP release, after 6 weeks, and before ISP repair and sacrifice.

RESULTS

Muscle volume on MRI decreased to a mean (±SD) of 80% ± 8% of the original volume after 6 weeks, remained stable at 78% ± 11% after 16 weeks, and decreased further to 69% ± 9% after 22 weeks in the control group. These findings were no different from those in group N22W (72% ± 9% at 6 weeks, 73% ± 6% at 16 weeks, and 67% ± 5% at 22 weeks). Conversely, the N6W group did not show a decrease in ISP volume after repair; this finding differed significantly from the response in the control and N22W groups. Fatty infiltration (on MRI) continuously increased in the control group (12% ± 4% at tendon release, 17% ± 4% after 6 weeks, 50% ± 9% after 16 weeks, and 60% ± 8% after 22 weeks) and the N6W group. However, application of anabolic steroids at the time of tendon release (N22W group) significantly reduced fatty infiltration after 16 (16% ± 5%; P < .001) and 22 weeks (22% ± 7%; P < .001).

CONCLUSION

In a sheep model of rotator cuff tendon tear, further muscle atrophy can be prevented with the application of anabolic steroids starting immediately after tendon repair. In addition, fatty muscle infiltration can largely be prevented if the steroids are applied immediately after tendon release.

CLINICAL RELEVANCE

Study findings may lead to the development of treatment strategies to prevent or reduce muscle degeneration caused by rotator cuff tendon tearing.

Low Serum Vitamin D Is Not Correlated With the Severity of a Rotator Cuff Tear or Retear After Arthroscopic Repair

BACKGROUND

Despite the essential role of vitamin D in muscle function, the prevalence of vitamin D deficiency has been reported to be very high. Recently, low vitamin D level was found to correlate with fatty degeneration of the rotator cuff tendon in humans and to negatively affect early healing at the rotator cuff repair site in an animal study. However, the effects of vitamin D level on severity of rotator cuff tear and healing after surgical repair have not been documented.

PURPOSE

To evaluate (1) the prevalence of vitamin D deficiency among patients who underwent arthroscopic repair for a full-thickness rotator cuff tear, (2) the relationship of vitamin D level with severity of the rotator cuff tear, and (3) surgical outcomes after repair.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A consecutive series of 91 patients (age, 50-65 years) who underwent arthroscopic rotator cuff repair for full-thickness, small-sized to massive tears were evaluated. Preoperative serum vitamin D levels (25-hydroxyvitamin) were analyzed to detect correlations with the features of a preoperative rotator cuff tear as well as postoperative structural and functional outcomes. All patients were followed clinically for a minimum of 1 year.

RESULTS

Preoperative vitamin D levels were deficient (<20 ng/mL) in 80 subjects (88%), insufficient (20-30 ng/mL) in 8 subjects (9%), and normal (>30 ng/mL) in 3 subjects (3%). No correlation was found between preoperative tear size (P = .23), extent of retraction (P = .60), degree of fatty infiltration of each cuff muscle (P > .50 each), or the global fatty infiltration index (P = .32). Similarly, no correlations were detected between vitamin D level and postoperative Sugaya type (P = .66) or any of the functional outcome scores (P > .50 each).

CONCLUSION

Low serum vitamin D level was not related to tear size, extent of retraction, or the degree of fatty infiltration in cuff muscles. It also had no significant relationships with postoperative structural integrity and functional outcomes after arthroscopic repair. The results suggest that low serum vitamin D level is not a significant risk factor for the severity of rotator cuff tear or poor healing after repair.

Role of vitamin D3 in treatment of lumbar disc herniation--pain and sensory aspects: study protocol for a randomized controlled trial

BACKGROUND

Vitamin D receptors have been identified in the spinal cord, nerve roots, dorsal root ganglia and glial cells, and its genetic polymorphism association with the development of lumbar disc degeneration and herniation has been documented. Metabolic effects of active vitamin D metabolites in the nucleus pulposus and annulus fibrosus cells have been studied. Lumbar disc herniation is a process that involves immune and inflammatory cells and processes that are targets for immune regulatory actions of vitamin D as a neurosteroid hormone. In addition to vitamin D's immune modulatory properties, its receptors have been identified in skeletal muscles. It also affects sensory neurons to modulate pain. In this study, we aim to study the role of vitamin D3 in discogenic pain and related sensory deficits. Additionally, we will address how post-treatment 25-hydroxy vitamin D3 level influences pain and sensory deficits severity. The cut-off value for serum 25-hydroxy vitamin D3 that would be efficacious in improving pain and sensory deficits in lumbar disc herniation will also be studied.

METHODS/DESIGN

We will conduct a randomized, placebo-controlled, double-blind clinical trial. Our study population will include 380 cases with one-level and unilateral lumbar disc herniation with duration of discogenic pain less than 8 weeks. Individuals who do not have any contraindications, will be divided into three groups based on serum 25-hydroxy vitamin D3 level, and each group will be randomized to receive either a single-dose 300,000-IU intramuscular injection of vitamin D3 or placebo. All patients will be under conservative treatment. Pre-treatment and post-treatment assessments will be performed with the McGill Pain Questionnaire and a visual analogue scale. For the 15-day duration of this study, questionnaires will be filled out during telephone interviews every 3 days (a total of five times). The initial and final interviews will be scheduled at our clinic. After 15 days, serum 25-hydroxy vitamin D3 levels will be measured for those who have received vitamin D3 (190 individuals).

TRIAL REGISTRATION

Iranian Registry for Clinical Trials ID: IRCT2014050317534N1 (trial registration: 5 June 2014).

Sports health benefits of vitamin d

CONTEXT

Vitamin D is a potent secosteroid hormone that provides many skeletal and extraskeletal health benefits. Musculoskeletal injury prevention and recovery are potentially affected by sufficient circulating levels of the storage form of vitamin D: 25-hydroxyvitamin D3, or 25(OH)D. Vitamin D deficiency can exist among young, active, and healthy people, which may put them at increased risk for injury and prolonged recovery.

EVIDENCE AQUISITION

PubMed was searched using vitamin D and skeletal muscle, vitamin D and athletic performance, and vitamin D review articles. Studies from the 1930s to 2012 were used for the review.

RESULTS

There is strong correlation between vitamin D sufficiency and optimal muscle function. Increasing levels of vitamin D reduce inflammation, pain, and myopathy while increasing muscle protein synthesis, ATP concentration, strength, jump height, jump velocity, jump power, exercise capacity, and physical performance. 25(OH)D levels above 40 ng/mL are required for fracture prevention, including stress fractures. Optimal musculoskeletal benefits occur at 25(OH)D levels above the current definition of sufficiency (> 30 ng/mL) with no reported sports health benefits above 50 ng/mL.

CONCLUSIONS

Vitamin D deficiency is common in athletes. For athletes presenting with stress fractures, musculoskeletal pain, and frequent illness, one should have a heightened awareness of the additional likely diagnosis of vitamin D deficiency. Correction of this deficiency is completed by standardized and supervised oral supplementation protocols producing significant musculoskeletal sports health benefits.

2013 Neer Award: Effect of the adipose-derived stem cell for the improvement of fatty degeneration and rotator cuff healing in rabbit model

BACKGROUND

This study was conducted to verify the effects of adipose-derived stem cells (ADSCs) on tendon healing and reversal of fatty infiltration in a chronic rotator cuff tear model by using the rabbit subscapularis (SSC).

METHODS

The SSC insertions in 32 rabbits were cut bilaterally. After 6 weeks, secondary procedures were performed bilaterally, dividing the rabbits into 4 groups of 8 rabbits each as follows: the ADSC+repair group, saline+repair group, ADSC-only group, and saline-only group. A fifth group of 8 rabbits served as normal controls (control group). Electromyographic, biomechanical, and histologic analyses were performed 6 weeks after the secondary procedures.

RESULTS

All SSC tendons in the ADSC-only and saline-only groups failed to heal and were excluded from the electromyographic and biomechanical tests. On electromyographic evaluation, the ADSC+repair group exhibited a larger compound muscle action potential area than the saline+repair group (11.86 ± 2.97 ms · mV vs 9.42 ± 3.57 ms · mV, P = .029), and this response was almost at the level of the control group (13.17 ± 6.6 3 ms · mV, P = .456). Biomechanically, the load-to-failure of the ADSC+repair group (87.02 ± 29.81 N) was higher than that of the saline+repair group (59.85 ± 37.77 N), although this difference did not reach statistical significance (P = .085). Histologically, the mean proportions of fatty infiltration in the SSC muscles were 29% ± 15%, 43% ± 9%, 51% ± 14%, 63% ± 10%, and 18% ± 9% for the ADSC+repair, saline+repair, ADSC-only, saline-only, and control groups, respectively (P < .001). The degree of fat staining increased from the ADSC+repair group (unclear or weak) to the saline-only group (strongly present).

CONCLUSION

Local administration of ADSCs might have the possibility to improve muscle function and tendon healing and decrease fatty infiltration after cuff repair.

Vitamin D insufficiency in patients with THA: prevalence and effects on outcome

BACKGROUND

The consequences of vitamin D insufficiency in the elderly remain controversial. The prevalence and potential effects of its chronic insufficiency on quality of life and physical function in patients undergoing THA have received little attention.

QUESTION/PURPOSES

We determined (1) prevalence of preoperative vitamin D insufficiency in patients undergoing THA and (2) relationships of insufficiency to patient-perceived outcomes (PPOs) and hip scores.

METHODS

We retrospectively reviewed 62 consecutive patients who underwent 66 primary THAs. We excluded two patients with missing data and the second hip of bilateral THAs, leaving 60 patients (60 hips) for final inclusion. Based on preoperative plasma 25-hydroxyvitamin-D3 levels, patients were retrospectively assigned into a normal or insufficient group. We used two different thresholds (20 and 30 ng/mL) to define insufficiency; groups were set twice. We compared demographics, BMI, American Society of Anesthesiologists score, Charlson Comorbidity Index; albumin, transferrin, calcium levels; and total lymphocyte count between groups. The insufficient group had a higher mean BMI with the 20-ng/mL cutoff but not with the 30-ng/mL cutoff. We compared the 20-ng/mL cutoff groups (adjusting for BMI) and the 30-ng/mL cutoff groups in terms of preoperative and postoperative Quality of Well-being Scale, SF-36, WOMAC, Harris hip, and Merle d'Aubigné-Postel scores. Mean followup was 11 months (range, 3-24 months).

RESULTS

The prevalence of vitamin D insufficiency was 30% (using 20 ng/mL) and 65% (using 30 ng/mL). Preoperative and postoperative Harris hip and Merle d'Aubigné-Postel scores were lower in patients with insufficiency using 30 ng/mL. No differences in PPOs or hip scores were found using 20 ng/mL.

CONCLUSIONS

Hypovitaminosis D was common in patients with THA and associated with lower hip scores. Standardization of the definition of hypovitaminosis D is urgently needed so that further studies can properly evaluate its real prevalence, potential negative effects on function, and therapeutic effects of reversing insufficiency before THA.

Effect of diet-induced vitamin D deficiency on rotator cuff healing in a rat model

BACKGROUND

Few studies have considered hormonal influences, particularly vitamin D, on healing.

HYPOTHESIS

Vitamin D deficiency would have a negative effect on the structure of the healing tendon-bone interface in a rat model and would result in decreased tendon attachment strength.

STUDY DESIGN

Controlled laboratory study.

METHODS

Vitamin D deficiency was induced in 28 male Sprague-Dawley rats using a specialized vitamin D-deficient diet and ultraviolet light restriction. Serum levels of vitamin D were measured after 6 weeks. These vitamin D-deficient animals (experimental group) plus 32 rats with normal vitamin D levels (controls) underwent unilateral detachment of the right supraspinatus tendon from the greater tuberosity of the humerus, followed by immediate repair using bone tunnel suture fixation. The animals were sacrificed at 2- and 4-week intervals after surgery for biomechanical analysis. A paired t test was used to compare serum vitamin D levels at day 0 and at 6 weeks. A nonparametric Mann-Whitney U test was used to compare load-to-failure and stiffness values between the experimental group and controls. Bone density and new bone formation at the tendon insertion site on the greater tuberosity were assessed with micro-computed tomography (CT). The organization of collagen tissue, new bone formation, vascularity at the tendon-bone interface, fibrocartilage at the tendon-bone interface, and collagen fiber continuity between the tendon and bone tissue were evaluated with safranin O and picrosirius red staining.

RESULTS

Blood draws confirmed vitamin D deficiency at 6 weeks compared with time zero/baseline for rats in the experimental group (10.9 ng/mL vs 6.5 ng/mL, respectively; P < .001). Biomechanical testing demonstrated a significant decrease in load to failure in the experimental group compared with controls at 2 weeks (5.8 ± 2.0 N vs 10.5 ± 4.4 N, respectively; P < .006). There was no difference in stiffness at 2 weeks between the control and experimental groups. At 4 weeks, there was no significant difference in load to failure or stiffness between the control and experimental groups. Histological analysis showed less bone formation and less collagen fiber organization in the vitamin D-deficient specimens at 4 weeks as compared with controls. Micro-CT analysis showed no significant difference between groups for total mineral density and bone volume fraction of cortical, whole, or trabecular bone at 4 weeks.

CONCLUSION

The biomechanical and histological data from this study suggest that low vitamin D levels may negatively affect early healing at the rotator cuff repair site.

CLINICAL RELEVANCE

It is estimated that 1 billion people worldwide are vitamin D deficient. In the deficient state, acutely injured rotator cuffs may have a reduced ability for tendon healing. Further studies are needed to determine the exact mechanism by which vitamin D affects tendon healing and whether vitamin D supplementation can improve rotator cuff tendon healing and reduce the incidence of retears.