Evidence for an inherited predisposition contributing to the risk for rotator cuff disease

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

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

Identification of rare genetic variants for rotator cuff tearing and repair in high-risk pedigrees

Background

Common genetic variants with small effect sizes have been associated with rotator cuff tearing although very few rare, highly penetrant variants have been identified. The purpose of this pilot study was to identify dominant coding variants that segregated with affected individuals in pedigrees at high risk for rotator cuff tears (RCTs). We hypothesize that rare variants contribute to symptomatic RCTs and that they can be identified in related cases with a full-thickness tear requiring surgical management.

Methods

We used the Utah Population Database to identify pedigrees that exhibited a significant excess of individuals who had undergone surgical repair of a full-thickness RCT. We analyzed whole exome sequence analysis to identify rare coding variants in 9 independent affected cousin pairs (first or second cousins) who had undergone arthroscopic surgery for repair of a full-thickness RCT (mean age at diagnosis 68 years). Validation of association of the candidate variants with risk for rotator cuff tearing was accomplished utilizing data from the UK Biobank and a separate cohort of unrelated cases of full-thickness RCTs.

Results

A total of 82 rare (minor allele frequency <0.005) coding variants were identified as shared in at least one cousin pair affected with full-thickness rotator cuff tearing belonging to a high-risk pedigree, which included variants in RUNX1, ADAM12, TGFBR2, APBB1, PDLIM7, LTBP1, MAP3K4, and MAP3K1. Analysis of 39 of these variants with data available in the UK Biobank (3899 cases with rotator cuff injury and 11,697 matched controls; mean case age 59.9 years) identified a significant association with the APBB1 gene (OR = 2.37, P = .007, uncorrected). The PDLIM7 allele was found to be in significant excess in RCT cases in a separate cohort of Utah patients with full-thickness RCTs (10 carriers out of 458 independent, unrelated patients; minor allele frequency of 0.022) compared to a minor allele frequency of 0.0058 for the European (non-Finnish) control population rate (749 carriers out of 128612 tested) (chi-square test: 19.3 [P < .001]).

Discussion

The analysis of closely related individuals with confirmed full-thickness RCTs from high-risk pedigrees has identified 82 rare, shared candidate genetic predisposition coding variants. Association of the PDLIM7 allele with risk for tear was confirmed in an independent cohort of RCTs. Further analysis of the variant alleles is required for confirmation of these genes in rotator cuff tearing.

Significant Association between a Diagnosis of Hypovitaminosis D and Rotator Cuff Tear, Independent of Age and Sex: A Retrospective Database Study

PURPOSE

As high rates of vitamin D deficiency have been demonstrated in orthopedic patient cohorts, this study aimed to characterize the association between a diagnosis of hypovitaminosis D and primary rotator cuff tear (RCT), primary rotator cuff repair (RCR), and postoperative complications in different sex and age cohorts.

METHODS

In this retrospective cohort study using PearlDiver, a nationwide administrative claims database, records for all patients aged 30 to 89 yr who received a diagnosis of hypovitaminosis D between January 1, 2011, and October 31, 2018, were queried. Rates of primary RCT, primary RCR, and postoperative complications including subsequent surgery were calculated within sex- and age-specific cohorts and compared with matched control cohorts using multivariable logistic regression.

RESULTS

Among the 336,320 patients included in the hypovitaminosis D cohort, these patients were significantly more likely to experience an RCT (odds ratio (OR), 2.70; 95% confidence interval (CI), 2.55-2.85) as well as a full-thickness RCT (OR, 2.36; 95% CI, 2.17-2.56) specifically within 2 yr of their diagnosis. Women with hypovitaminosis D were more likely to undergo surgery to address their full-thickness tears (OR, 1.37; 95% CI, 1.09-1.74). There was no difference in the rates of revision RCR or irrigation and debridement. However, women with hypovitaminosis D were significantly more likely to undergo manipulation under anesthesia (OR, 1.16; 95% CI, 1.03-1.31).

CONCLUSIONS

Patients diagnosed with hypovitaminosis D were significantly more likely to suffer from a primary RCT and to undergo manipulation under anesthesia within a year of their RCR. Although many risk factors for RCT are unmodifiable, vitamin D deficiency is a readily modifiable risk factor with several treatment regimens demonstrating positive effects on musculoskeletal health.

Anterolateral Acromioplasty Reduces Gliding Resistance Between the Supraspinatus Tendon and the Coracoacromial Arch in a Cadaveric Model

Purpose

To investigate the gliding resistance dynamics between the supraspinatus (SSP) tendon and the coracoacromial arch, both before and after subacromial decompression (anterolateral acromioplasty) and acromion resection (acromionectomy).

Methods

Using 4 fresh-frozen cadaveric shoulders, acromion shapes were classified (2 type I and 2 type III according to Bigliani). Subacromial bursa and coracoacromial ligament maintenance replicated physiologic sliding conditions. Gliding resistance was measured during glenohumeral abduction (0° to 60°) in internal rotation (IR) and external rotation (ER). Peak gliding resistance between the SSP tendon and the coracoacromial arch was determined and compared between intact, anterolateral acromioplasty, and acromionectomy.

Results

Peak SSP gliding resistance during abduction in an intact shoulder was significantly higher in IR than in ER (4.1 vs 2.1 N, P < .001). The mean peak SSP gliding resistance during 0° to 60° glenohumeral abduction in IR in the intact condition was significantly higher compared with the subacromial decompression condition (4.1 vs 2.8 N, P = .021) and with the acromionectomy condition (4.1 vs 0.9 N, P < .001). During 0° to 60° glenohumeral abduction in ER, mean peak SSP gliding resistance in the intact condition was not significantly different compared with the subacromial decompression condition (2.1 vs 2.0 N, P = .999). The 2 specimens with a hooked (i.e. type III) acromion showed significantly higher mean peak SSP gliding resistance during glenohumeral abduction in IR and ER when compared with the 2 specimens with a flat (i.e. type I) acromion (IR: 5.8 vs 3.0 N, P = .006; ER: 2.8 vs 1.4 N, P = .001).

Conclusions

In this cadaveric study, peak gliding resistance between the SSP tendon and the coracoacromial arch during combined abduction and IR was significantly reduced after anterolateral acromioplasty and was significantly higher in specimens with a hooked acromion.

Clinical Relevance

The clinical benefit of subacromial decompression remains unclear. This study suggests that anterolateral acromioplasty might reduce supraspinatus gliding resistance in those with a hooked acromion and in the typical "impingement" position.

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.

Current Understanding and New Advances in the Surgical Management of Reparable Rotator Cuff Tears: A Scoping Review

Rotator cuff (RC) tears are among the most common musculoskeletal disorders and can be associated with pain, weakness, and shoulder dysfunction. In recent years, there have been significant advances with regard to the understanding of rotator cuff disease and its management. With technological improvements and advanced diagnostic modalities, there has been much progress as to improved understanding of the pathology. Similarly, with advanced implant designs and instrumentation, operative techniques have evolved. Furthermore, refinements in postoperative rehabilitation protocols have improved patient outcomes. In this scoping review, we aim to provide an overview of the current knowledge on the treatment of rotator cuff disorders and to highlight recent advances in its management.

Association between the rs820218 Variant within the SAP30BP Gene and Rotator Cuff Rupture in an Amazonian Population

BACKGROUND

Rotator cuff disease is one of the leading causes of musculoskeletal pain and disability, and its etiology is most likely multifactorial but remains incompletely understood. Therefore, the objective of this research was to investigate the relationship of the single-nucleotide rs820218 polymorphism of the SAP30-binding protein (SAP30BP) gene with rotator cuff tears in the Amazonian population.

METHODS

The case group consisted of patients who were operated on due to rotator cuff tears in a hospital in the Amazon region between 2010 and 2021, and the control group was composed of individuals who were selected after negative physical examinations for rotator cuff tears. Genomic DNA was obtained from saliva samples. For the genotyping and allelic discrimination of the selected single nucleotide polymorphism (rs820218) in the SAP30BP gene, real-time PCR was performed.

RESULTS

The frequency of the A allele in the control group was four times as high as that in the case group (AA homozygotes); an association of the genetic variant rs820218 of the SAP30BP gene with rotator cuff tears was not established (p = 0.28 and 0.20), as the A allelic frequency is ordinarily low in the general population.

CONCLUSIONS

The presence of the A allele indicates protection against rotator cuff tears.

RNA-Seq reveals distinct transcriptomic differences in rotator cuff tendon based on tear etiology and patient sex

Rotator cuff tears are a common pathology in the shoulder and generally have two underlying etiologies: traumatic and degenerative. Little is known about the molecular underpinning of these etiologies. Here we queried transcript level differences in tear etiology stratified by sex in 31 patients with rotator cuff tears. Tendon tissues were isolated from females (N = 16) and males (N = 15) with traumatic (N = 16) or degenerative (N = 15) tears during arthroscopy. Differentially expressed transcripts were identified by RNA-seq and biological processes were probed computationally. Expression of some transcripts was validated by real-time quantitative polymerase chain reaction (qPCR). We identified 339 and 336 transcripts differentially expressed by tear etiology in females and males, respectively, at a fold-change greater than |2|. In females, GSTM1, MT1G, S1008A, ACSM3, DSC, FAM110C, and VNN2 were elevated in traumatic tears representing metabolic/catabolic processes, and immune response whereas CHAD, CLEC3A, IBSP, TNMD, APLNR, and CPA3 were elevated in degenerative tears representing tissue morphogenesis and developmental processes, angiogenesis, and extracellular matrix organization. In males, ELOA3B, CXCL8, ADM, TNS4, and SPOCK1 were elevated in traumatic tears representing localization of endoplasmic reticulum, chromosome organization, leukocyte/neutrophil degranulation, and protein transport whereas MYL2, TNNC1, MB, CPA3, APLNR, and CA3 were highly upregulated in degenerative tears representing muscle cell differentiation and development and angiogenesis. Numerous novel lncRNAs were identified to be differentially expressed by tear etiology in both sexes. Real-time qPCR confirmed RNA-seq data. This study improves our understanding of tendon biology based on underlying etiology (trauma or degeneration) in a sex-specific manner. These findings may help drive clinical decision-making in females and males with traumatic and degenerative shoulder injuries.

Animal Models of Rotator Cuff Injury and Repair: A Systematic Review

There are a large number of animal studies on rotator cuff injury and repair, but a lack of detailed research and evaluation on the animal models. This systematic review aims to provide a framework for animal studies and repair patches for rotator cuff injury. Four hundred nine animal studies were included, of which the most common animal model of rotator cuff injury is rat (53.56%), the most common site of rotator cuff injury is the supraspinatus tendon (62.10%), and the most common injury type (degree) is acute tear (full thickness) (48.41%). The most common research purpose is to evaluate the repair effect of the patch (24.94%), followed by the observation of pathophysiological changes after rotator cuff injury (20.87%). Among the five types of repair patch materials including nondegradable and degradable synthetic materials, autologous and allogeneic tissues, and naturally derived biomaterial, the last one is the mostly used (52.74%). For different animal models, the rodent models (rat and mouse) are the most commonly used and probably the most suitable species for preliminary studies of rotator cuff injury; the rabbit, canine, sheep, and goat models are more suitable for biomechanical performance testing, rehabilitation training, and validation of surgical methods; and the nonhuman primate models (monkey and baboon) are the closest to human, but it is more difficult to carry out the animal studies on them because of ethical issues, high feeding cost, and management difficulties.

Aktuelle Aspekte der Behandlung der Rotatorenmanschette

Rotatorenmanschettenrupturen gehören zu den häufigsten muskuloskeletalen Erkrankungen und können mit ausgeprägten Schmerzen und Funktionseinschränkungen einhergehen. Für ihre Entstehung ist eine Vielzahl von Faktoren relevant, u. a. die individuelle Anatomie des Akromions. Mit Hilfe der heutigen technischen Möglichkeiten wurde nun festgestellt, dass zusätzlich zu seiner lateralen Ausdehnung auch die sagittale Ausdehnung des Akromions eine Rolle zu spielen scheint. Die bildgebende Darstellung der Rotatorenmanschette (RM) hat von den technischen Fortschritten der letzten Jahrzehnte ebenfalls profitiert. Magnetresonanztomographie (MRT) und MR-Arthrographie werden heute flächendeckend eingesetzt. Letztere bietet die höchste Sensitivität für die Entdeckung selbst kleiner Partialläsionen. Neue Sequenzen und Nachbearbeitungsmöglichkeiten können als hilfreiche tools für die operative Planung eingesetzt werden. Grundsätzlich richtet sich die Behandlung der RM neben der Symptomatik nach der Rupturgenese und -morphologie sowie der erwarteten Gewebequalität des Muskel-Sehnen-Kontinuums. Auch das Gesamtprofil, die Erwartungshaltung und die Rehabilitationsmöglichkeiten des Patienten sind wichtig. Die heutigen operativen Techniken werden durch spannende Entwicklungen der Industrie mitbestimmt, die in den letzten Jahren immer bessere Fadenankersysteme, aber auch Augmentationsmaterialien auf den Markt gebracht hat. Letztere zielen nicht nur auf die mechanische Verstärkung der Sehnenrekonstruktion, sondern auch auf die Optimierung der biologischen Eigenschaften des Konstrukts ab. Hinsichtlich Fixation konnte die biomechanische Forschung zeigen, dass zweireihige oder Suture-Bridge-Fixationen einreihigen oder transossären Fixationen überlegen sind. Diese Überlegenheit im Labor spiegelt sich noch nicht klar in den klinischen Ergebnissen wider, dennoch sind die meisten Chirurgen heute auf diese Technik übergegangen. Was die postoperative Nachbehandlung angeht, stellen jüngste randomisiert-kontrollierte Untersuchungen das Konzept der postoperativen Immobilisation in Abduktion in Frage. Hier scheint das letzte Wort noch nicht gesprochen zu sein.

Anterolateral Acromioplasty Does Not Change the Critical Shoulder Angle and Acromion Index in a Clinically Relevant Amount

PURPOSE

Assessment on whether radiographic parameters of the acromion measured in radiographs change significantly after anterolateral acromioplasty.

METHODS

This retrospective study included patients that underwent an arthroscopic anterolateral acromioplasty between January 2014 and September 2020. n = 435 subjects with high-quality preoperative and postoperative radiographs according to Suter-Henninger criteria were included in the final assessment. All measurements were independently performed by the first and second author in a blinded fashion using dicomPACS software: acromion index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), beta angle, acromio-humeral distance (AHD), Aoki angle, frontal supraspinatus outlet angle (FSOW), and acromion type, according to Bigliani. SPSS software was used for statistical analysis.

RESULTS

The beta angle and the CSA did not significantly change after operation (alpha power 0.32 and 0.11, respectively). In a subgroup analysis of patients with a pathological CSA >35° (n = 194), the CSA changed from 38.62 (range: 35.08-47.52, SD 2.83) to 38.04 (range: 29.18-48.12, SD 3.77) postoperatively (P = .028) (Fig 8). All other parameters changed significantly after operation (AI, AHD, FSOW, and Aoki; P = .001, LAA; P = .039) (Fig. 9). The interobserver and intraobserver reliability was good to excellent in the majority of measured values. Mean patient age was 59.2 years (range: 18.1-87.1; SD 11.3), mean height was 1.73 meters (range: 1,50-1.98, SD 0.09), mean weight was 80.2 kg (range: 37.0-133.0, SD 16.68), and mean body mass index was 26.6 (range: 0.0-46.1, SD 4.73).

CONCLUSION

Anterolateral acromioplasty producing a flat acromion undersurface did not result in a significant change of the CSA in the study population. Pathological preoperative CSA values of >35° were significantly reduced but not to normal values, but only by a small amount that puts the clinical relevance into question.

LEVEL OF EVIDENCE

IV, diagnostic study, case series.

Genetic Characterization in Familial Rotator Cuff Tear: An Exome Sequencing Study

Background: multiple gene variants seem to contribute to rotator cuff (RC) tear susceptibility. The aim of the study is to perform an exome sequencing analysis within a family to identify rare gene variants predisposing to the development of RC tear. Material and methods: the exome sequencing was conducted in a family consisting of four individuals, two healthy and the remaining ones with bilateral RC tears. Variants in common among the two affected subjects were selected, and those in common with the healthy subject and those with a frequency >1% were removed. The potential pathogenicity of the variants was investigated using the predictions of several in silico tools from VarSome. Results: the exome sequencing yielded approximately 600,000 variants per patient, subsequently filtered according to frequency <1% and absence of association with other diseases. Removing variants common with the healthy subject, 348 rare variants among 248 genes were identified. Based on the risk of damaging, three candidate genes for RC tear were found: COL23A1, EMILIN3, and HDAC10. Conclusion: this is the first whole-exome sequencing analysis within a family to explore genetic predisposition in RC tear. The results reveal the presence of common damaging variants among affected individuals in the COL23A1, EMILIN3, and HDAC10 genes.

Evidence for excess familial clustering of Post Traumatic Stress Disorder in the US Veterans Genealogy resource

A genealogy of the United States has been record-linked to National Veteran's Health Administration (VHA) patient data to allow non-identifiable analysis of familial clustering. This genealogy, including over 70 million individuals linked to over 1 million VHA patients, is the largest such combined resource reported. Analysis of familial clustering among VHA patients diagnosed with Post Traumatic Stress Disorder (PTSD) allowed a test of the hypothesis of an inherited contribution to PTSD. PTSD is associated strongly with military service and extended familial clustering data have not previously been presented. PTSD-affected VHA patients with genealogy data were identified by presence of an ICD diagnosis code in the VHA medical record in at least 2 different years. The Genealogical Index of Familiality (GIF) method was used to compare the average relatedness of VHA patients diagnosed with PTSD with their expected average relatedness, estimated from randomly selected sets of matched linked VHA patient controls. Relative risks for PTSD were estimated in first-, second-, and third-degree relatives of PTSD patients who were also VHA patients, using sex and age-matched rates for PTSD estimated from all linked VHA patients. Significant excess pairwise relatedness, and significantly elevated risk for PTSD in first-, second-, and third-degree relatives was observed; multiple high-risk extended PTSD pedigrees were identified. The analysis provides evidence for excess familial clustering of PTSD and identified high-risk PTSD pedigrees. These results support an inherited contribution to PTSD predisposition and identify a powerful resource of high-risk PTSD pedigrees for predisposition gene identification.

The role of familial predisposition in imaging-confirmed atraumatic rotator cuff tears

BACKGROUND

The etiology of atraumatic rotator cuff tears is not completely understood. Limited data suggest the role of genetic and familial predisposition in the etiology of rotator cuff tears. The purpose of this study was to assess whether there is an increased likelihood of rotator cuff tears in family members of patients with rotator cuff tears vs. those without tears. This would provide evidence for whether there is an association between familial predisposition and rotator cuff tearing.

METHODS

Patients presenting to a shoulder clinic were recruited in this study. They provided information on personal medical history, shoulder symptoms, and family history of rotator cuff tears. The diagnosis of rotator cuff tears was based on imaging (magnetic resonance imaging or computed tomography arthrogram) confirmation of a structural defect in the rotator cuff. The association between family history of rotator cuff problems and the likelihood of an imaging-confirmed rotator cuff tear diagnosis was evaluated using multivariate logistic regression, adjusting for age, sex, race/ethnicity, cigarette smoking, hypertension, diabetes, and depression.

RESULTS

In our cohort of 2335 patients, 52.6% (n = 1229) of patients had a rotator cuff tear. Among patients with tears, 17.9% (n = 220) of patients reported a family history of rotator cuff issues vs. 11.1% (n = 123) in patients without tears. A family history of rotator cuff problems was significantly associated with the diagnosis of an imaging-confirmed rotator cuff tear (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.71, 2.95). Other confounding variables such as increasing age (OR 1.06, 95% CI 1.05, 1.07) and Hispanic race/ethnicity as compared to non-Hispanic white race/ethnicity (OR 1.48, 95% CI 1.07, 2.05) were significantly associated with rotator cuff tears. Sex, smoking, hypertension, diabetes, and depression were not significantly associated with rotator cuff tearing.

CONCLUSION

Our study shows that individuals with rotator cuff tears were more than 2 times as likely to have a family member with a tear as compared to patients without tears. Increasing age and patients who identified as being of Hispanic ancestry were also significantly associated with higher odds of rotator cuff tears.

Analysis of Risk Factors, Complications, Reoperations, and Demographics Associated With Open and Arthroscopic Rotator Cuff Repair: An Analysis of a Large National Database

PURPOSE

To assess the national trends in arthroscopic and open rotator cuff repair surgery and the associated demographics, complications, and risk factors specific to each procedure.

METHODS

A retrospective cohort study was performed using the National Surgical Quality Improvement Program (NSQIP) dataset between the years 2007 and 2018. Patients were identified using Common Procedural Terminology codes for open and arthroscopic rotator cuff repair. Variables collected including basic demographics, procedural, and outcome specific variables as available through the NSQIP repository. Appropriate statistical measures were used to compare the groups, with the χ² test used for categorical variables and t test for continuous variables.

RESULTS

The arthroscopic cohort comprised 39,013 patients; the open group consisted of 8,664. Reported arthroscopic and open cases increased significantly between 2007 and 2018 from 135 to 7,269 and 65 to 1,168, respectively. Average operative time for arthroscopic procedure was 89 minutes and 76 minutes for open. The open group consisted of a slightly greater percentage of smokers, 18.3% versus 15.2%, and patients with diabetes, 18.2% versus 15.9%, both of which were statistically significant (P < .001). Open cases had an odds ratio of 3.05 for superficial infections and 7.40 for deep infections, both of which were statistically significant (P < .001). The open cohort also had an odds ratio of 1.71 for unplanned readmissions when compared with the arthroscopic cohort, which was also statistically significant (P < .001).

CONCLUSIONS

According to the NSQIP database, the increase in arthroscopic procedures is significantly outpacing the increase in open procedures during this study period, which matches the trends seen in previous studies. Patients with diabetes and who smoke also represent a greater risk group for postoperative complications when undergoing open surgery. These findings suggest that perhaps the decision to pursue one technique over the other may be influenced both by provider preference and patient-related factors.

LEVEL OF EVIDENCE

III, retrospective comparative trial.

"Current concepts and expert practice report: Augmentation of rotator cuff repairs"

Rotator cuff tears are common shoulder injuries expected to increase with the growth of the aging population. Although a small subset of patients with low functional demands can be treated nonoperatively, surgical intervention is a cost-effective solution, which can restore shoulder function and help patients return to activity sooner. While multiple surgical options are available, rotator cuff repair is a highly utilized procedure with varying success. Due to a large proportion of rotator cuff repairs still failing to completely heal, this procedure requires careful planning to achieve anatomical and biomechanically stability. New technology and techniques are being explored to help increase the success of rotator cuff repairs with an increasing focus on augmentation. The current article gives a brief overview of pertinent anatomy, treatment options, and challenges in healing of rotator cuff repairs. Thereafter, the merits of different types of rotator cuff repair augmentation available will be discussed as well as the authors' experience in utilizing biologic augmentation and surgical technique.

Genetic variants associated with rotator cuff tearing utilizing multiple population-based genetic resources

BACKGROUND

The etiology of rotator cuff tearing is likely multifactorial, including a potential genetic predisposition. The purpose of the study was to identify genetic variants associated with rotator cuff tearing utilizing the UK Biobank (UKB) cohort, confirm variants using a separate genetic database, and evaluate tissue expression of genes with associated variants following rotator cuff tearing using RNA sequencing.

METHODS

Genome-wide association study (GWAS): A GWAS was performed using data from UKB with 5701 cases of rotator cuff injury. RNA sequencing analyses: rotator cuff biopsies were obtained from 24 patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair (cases) and 9 patients who underwent open reduction internal fixation for a proximal humerus fracture (controls). Total RNA was extracted and differential gene expression was measured by RNAseq for genes with variants associated with rotator cuff tearing.

RESULTS

The results of the UKB GWAS identified 3 loci that reached genome-wide statistical significance: 2 loci on chromosome 7 in GLCCI1 (rs4725069; P = 5.0E-09) and THSD7A (rs575224171; P = 5.3E-09), and 1 locus on chromosome 2 in ZNF804A (rs775583810; P = 3.9E-09). The association with rotator cuff injury of the GLCCI1 single-nucleotide polymorphism (SNP; rs4725069) was confirmed in the Kaiser Permanente Research Bank cohort (P = .008). Twenty previously reported SNPs in 12 genes were evaluated using summary statistics from the UKB GWAS, which confirmed 3 SNPs in TNC with rotator cuff injury (rs1138545, rs72758637, and rs7021589; all P < .0024). Of 17 genes with variants associated with rotator cuff injury (14 previously from literature plus 3 new genes from current UKB GWAS), TIMP2, Col5A1, TGFBR1, and TNC were upregulated (P < .001 for all) and THSD7A was downregulated (P = .005) in tears vs. controls in the RNA sequencing data set.

CONCLUSION

The UKB GWAS has identified 3 novel loci associated with rotator cuff tearing (ZNF804A, GLCCI1, THSD7A). Expression of the THSD7A gene was significantly downregulated in rotator cuff tears vs. controls supporting a potential functional role. Three previously reported SNPs in the TNC gene were validated in the UKB GWAS, supporting a role for this gene in rotator cuff tearing. Finally, TIMP2, Col5A1, TGFBR1, and TNC genes were found to have significantly upregulated tissue expression in cases vs. controls supporting a biologic role in tearing for these genes.

Footprint size matters: wider coronal greater tuberosity width is associated with increased rates of healing after rotator cuff repair

Background

The purpose of this study was to determine whether greater tuberosity morphology (1) could be measured reliably on magnetic resonance imaging (MRI), (2) differed between patients with rotator cuff tears (RCTs) compared with those without tears or glenohumeral osteoarthritis, or (3) differed between patients with rotator cuff repairs (RCR) who healed and those that did not.

Methods

This is a retrospective comparative study. (1) We measured greater tuberosity width (coronal and sagittal), lateral offset, and angle on MRI corrected into the plane of the humerus. To determine reliability, these measurements were made by two observers and intraclass correlation coefficients were calculated. (2) We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of a RCT or glenohumeral osteoarthritis. (3) We then compared these measurements between those patients with healed RCRs and those with evidence of retear on MRI. In this portion, we only included patients with both a preoperative and postoperative MRI at least 1 year from RCR. Postoperative MRIs were obtained to assess healing rates, not because of concern for failure. Those without tendon defects were considered healed.

Results

(1) In a validation cohort of 50 patients with MRI, all inter-rater intraclass correlation coefficients were greater than 0.75. (2) There were no differences between our RCT group of 110 patients and our comparison group of 100 patients in tuberosity coronal width, sagittal width, or lateral offset. The RCT group had a significantly smaller greater tuberosity angle (63 ± 4° vs 65 ± 5°, P = .003). (3) In our group of 110 RCRs, postoperative MRI scans were obtained at a mean follow-up of 23.6 ± 15.7 months showing 84 (76%) patients had healed RCRs. Larger coronal tuberosity width was associated with healing (1.3 ± 0.2 vs 1.2 ± 0.2 cm, P = .032), as was smaller tear width (P < .001), and retraction (P < .001). When coronal width was dichotomized, there was a significantly higher healing rate with a width over 1.2 cm (85 vs 66%, P = .02). No other greater tuberosity morphological characteristics were associated with RCR or postoperative healing.

Conclusion

RCTs do not appear to be associated with greater tuberosity morphology. Postoperative rotator cuff healing based on MRI is 76%. Higher rates of healing occur with a wider coronal tuberosity width (ie, rotator cuff tendon footprint). Consideration could be given to widening the footprint intraoperatively in an effort to improve healing rates although this remains to be validated.

Acromial morphology is not associated with rotator cuff tearing or repair healing

BACKGROUND

The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not.

METHODS

This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle.

RESULTS

In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001).

CONCLUSION

Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty.

Genetic Aspects in Shoulder Disorders

The influence of genetic inheritance has been increasingly investigated in shoulder disorders, such as rotator cuff injury, instability and frozen shoulder. Although the initial findings are enlightening, it is necessary to progressively build a database of genetic markers to catalog genomic profiles that, later, may contribute for predicting the risk of the disease, as well as to the development of better diagnostic and treatment tools. The present article seeks to update what is evidence of genetic studies in the literature for these diseases, from polymorphism analyses, expression of candidate genes in tissues and broad genomic association studies (GWAS). However, it is necessary to point out that there is great difficulty in replicating and using the findings, mainly due to the lack of statistical power, the high rate of false-positive results and the large number of variables involved.

SAP30BP gene is associated with the susceptibility of rotator cuff tear: a case-control study based on Han Chinese population

Background

Multiple studies have indicated that genetic components contribute significantly to the risk of rotator cuff tears. Previous studies have suggested that the SAP30BP gene may play an essential role in the development of rotator cuff tears. The aim of this study was to evaluate the potential association of the SAP30BP gene with the susceptibility to rotator cuff tears in a Han Chinese population.

Methods

A total of 394 patients with rotator cuff tears and 998 healthy controls were included in the study. Twelve tag single nucleotide polymorphisms (SNPs) located in the region of the SAP30BP gene were selected for genotyping. Genetic association analyses were performed using χ² tests for each SNP. Significant associations were searched in the GTEx database for their functional consequences.

Results

SNP rs820218 was significantly associated with rotator cuff tears (χ² = 9.49, P = 0.0021, OR [95% CI] = 0.67 [0.52–0.87]). In addition, SNP rs820218 was found to be significantly associated with the gene expression level of SAP30BP in whole blood (NES = 0.12, P = 1.00 × 10⁻⁶).

Conclusion

Our study has shown that the genetic polymorphism of SAP30BP contributes to the risk of rotator cuff tears in Chinese Han people. Individuals with the A allele for SNP rs820218 were less susceptible to developing rotator cuff tears.

Family Predisposition for Rotator Cuff Tear and Other Tendinopathies - A Case-Control Study

Objective  To evaluate the prevalence of family history of rotator cuff tear and the presence of tendinopathy in other joints in patients with rotator cuff tears and to compare them with paired controls. To estimate the odds ratio for rotator cuff tear for these two risk factors. Methods  We performed a case-control study comparing patients submitted to treatment for rotator cuff tear with asymptomatic controls. All cases and controls were evaluated by imaging exams and matched by age (±2 years) and gender. We conducted an interview using a standardized questionnaire, and collected data on various risk factors. Results  We evaluated 144 patients, 72 per group. Patients with rotator cuff tears reported a higher number of consanguineous relatives who underwent treatment for the same disease and tendon injuries in other joints compared to the controls ( p  = 0.005 and p  = 0.045 respectively). Individuals with a family history of treatment for rotator cuff tear or with tendinopathies in other joints were more likely to present a rotator cuff tear, with odds ratios of 3.3 (95% confidence interval [95%CI] = 1.4-7.7) and 2.7 (95%CI = 1.1-6.9) respectively. Conclusions  Patients with rotator cuff tear have a higher prevalence of family members with the same disease and tendinopathies or tendon injuries in other joints. The presence of consanguineous relatives with treatment for rotator cuff and tendinopathies in other joints are risk factors for the presence of rotator cuff tears.

Gene Expression in Torn Rotator Cuff Tendons Determined by RNA Sequencing

Background:

Although the cause of rotator cuff tearing is likely multifactorial and a genetic predisposition has been proposed, the biochemical basis remains unknown.

Purpose:

To determine gene expression profiles in torn rotator cuff tendon tissue through use of RNA sequencing.

Study Design:

Controlled laboratory study.

Methods:

The supraspinatus tendon edge was biopsied in 24 patients undergoing arthroscopic rotator cuff repair for full-thickness supraspinatus rotator cuff tears. The supraspinatus tendon was also biopsied in 9 patients undergoing open reduction and internal fixation for a proximal humeral fracture (controls). Total RNA was extracted and sequenced. Differential gene expression was analyzed between the tear and control groups, and a secondary analysis was conducted between groups defined by an unbiased clustering.

Results:

Tear and control transcriptomes demonstrated significant differential expression in more than 3000 genes. The identified differential genes were highlighted in pathways involved in inflammation in control patients and extracellular matrix generation in patients with tears. Secondary analysis using unsupervised and thus unbiased hierarchical clustering revealed 2 clusters (c2 and c3). Cluster c3 contained smaller (P < .001) and less retracted (P = .018) tears (ie, tears earlier in the progression of rotator cuff disease) with increased expression of hypoxia target genes. Cluster c2 contained larger, more retracted tears (ie, tears further in the progression of rotator cuff disease) with increased expression of endothelial cell markers and chronic inflammation target genes. Tears in c2 had significantly worse healing rates compared with tears in c3 (0% vs 89%; P = .007).

Conclusion:

Smaller, less retracted tears had increased expression of hypoxia target genes and improved healing, whereas larger, more retracted tears were associated with endothelial cell markers and worse healing. Thus, hypoxia may be the inciting event for tear development, whereas with tear enlargement, a chronic, inflammatory, angiogenic process may predominate.

Clinical Relevance:

Identification of differential gene expression in rotator cuff tears may be a reliable tool to predict repair healing in the future.

Retears of the Rotator Cuff: An Ultrasonographic Assessment During the First Postoperative Year

Background

Surgical repair of rotator cuff (RC) tears is an effective treatment option. However, the prevalence of recurrent ruptures is high.

Hypothesis

Recurrent tears are a frequent complication of surgical repair of RC tears. Their incidence might be influenced by factors such as the patient's age and size of the initial tear.

Study Design

Case series; Level of evidence, 4.

Methods

Data from 90 adult patients who underwent arthroscopic RC repair between 2014 and 2017 and underwent an ultrasound examination 6 to 12 months after surgery were analyzed retrospectively. Massive tears were repaired using a double-row technique, and nonmassive tears were repaired with a single-row technique. Clinical records were reviewed for demographic information.

Results

All patients (57.8% women; 42.2% men) were older than 18 years (mean, 58.9 years). Of these patients, 30.0% (27/90) had massive tears, which were primarily found in patients ≥60 years (74.1%; 20/27). Complete healing was seen in 74.5% of all repairs during follow-up. A total of 23 patients (25.5%) had retears (13 complete; 10 partial), which were diagnosed by ultrasound imaging 6 to 12 months after the initial surgery. The occurrence of retears was more prevalent in patients with massive tears than in patients with nonmassive tears (40.7% vs 19.0%, respectively); the difference was statistically significant (P = .03). Reruptures occurred in 50.0% of patients older than 60 years with massive tears. Although patients older than 60 years had more recurrent tears (32.6%) compared with younger patients (18.2%), the difference was not statistically significant (P = .12).

Conclusion

One-quarter of the patients who had undergone surgical repair of an RC tear had recurrent ruptures. There was a statistically significant association between the initial massive tear and a retear. Patients older than 60 years showed a higher recurrence rate, but this difference lacked statistical significance. Reruptures occurred in 50.0% of patients older than 60 years with massive tears.

Genetic basis of rotator cuff injury: a systematic review

BACKGROUND

Rotator cuff disease is a widespread musculoskeletal pathology and a major cause of shoulder pain. Studies on familial predisposition suggest that genetic plays a role in the pathogenesis of rotator cuff disease. Several genes are responsible for rotator cuff disease. The aim of this study was to perform a systematic review on genetic association between rotator cuff disease and genes variations.

METHODS

A systematic review of the literature was performed, in accordance with the PRISMA guidelines. PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases were searched comprehensively using the keywords: "Rotator cuff", "Gene", "Genetic", "Predisposition", "Single-nucleotide polymorphism" and "Genome-wide association".

RESULTS

8 studies investigating genes variations associated with rotator cuff tears were included in this review. 6 studies were case-control studies on candidate genes and 2 studies were GWASs. A significant association between SNPs and rotator cuff disease was found for DEFB1, FGFR1, FGFR3, ESRRB, FGF10, MMP-1, TNC, FCRL3, SASH1, SAP30BP, rs71404070 located next to cadherin8. Contradictory results were reported for MMP-3.

CONCLUSION

Further investigations are warranted to identify complete genetic profiles of rotator cuff disease and to clarify the complex interaction between genes, encoded proteins and environment. This may lead to individualized strategies for prevention and treatment of rotator cuff disease.

LEVEL OF EVIDENCE

Level IV, Systematic Review.

Recovery of Range of Motion and Decrease in Pain after Progression of Supraspinatus Tendon Tear: A Case Report

Rotator cuff disease is one of the most prevalent shoulder disabilities especially in the elderly population. Tear progression is significantly greater in the symptomatic patients than in the asymptomatic ones. From these aspects, shoulder surgeons interpret surgical indications and counsel patients regarding the risk of non-operative treatments. However, there were a few reports that pain and duration of symptoms were not strongly associated with severity of rotator cuff tears, and non-operative management with physical therapy was effective. There have remained controversies for the treatment of rotator cuff tears.

A 59-year-old man with a sedentary work life experienced right shoulder pain with abduction at night. However, the pain kept worsening after two months, and he finally visited our clinic three months after the onset of pain. Magnetic resonance imaging in the coronal and axial planes showed effusion around the subacromial and subcoracoid bursae and joint-side tear of the supraspinatus tendon. A range of motion in the right shoulder was severely restricted at the initial visit of our clinic. After sufficient rehabilitation, the symptoms were not changed and an arthroscopic rotator cuff repair was scheduled. However, during waiting for surgery, he felt something popped in the right shoulder while wearing a jacket. Immediately after this, pain during motion and at night decreased, and he experienced no difficulty with activities of daily living and the surgery was cancelled. This is the first case with a recovery of range of motion and a decrease in pain after progression of a supraspinatus tendon tear.

Degenerative Rotator Cuff Tears: Refining Surgical Indications Based on Natural History Data

Degenerative rotator cuff tears are the most common cause of shoulder pain and have a strong association with advanced aging. Considerable variation exists in surgeons' perceptions on the recommended treatment of patients with painful rotator cuff tears. Natural history studies have better outlined the risks of tear enlargement, progression of muscle degeneration, and decline in the function over time. This information combined with the known factors potentially influencing the rate of successful tendon healing such as age, tear size, and severity of muscle degenerative changes can be used to better refine appropriate surgical indications. Although conservative treatment can be successful in the management of many of these tears, risks to nonsurgical treatment also exist. The application of natural history data can stratify atraumatic degenerative tears according to the risk of nonsurgical treatment and better identify tears where early surgical intervention should be considered.

Cryotherapy or gradual reloading exercises in acute presentations of rotator cuff tendinopathy: a randomised controlled trial

Objectives

Rotator cuff tendinopathies are the most common shoulder disorders. As persistent symptoms lasting more than 3 months have been shown to be a strong indicator of poor outcomes, it is important to have successful interventions in the acute stage. However, there is no evidence yet to guide clinical interventions in an acute pain context. The objective of this study was to compare the short-term effect of a 2-week gradual reloading exercises programme with the use of cryotherapy on symptoms and function for acute rotator cuff tendinopathy.

Methods

This simple-blind, randomised controlled trial included 44 participants with acute rotator cuff tendinopathy who were randomly allocated to either the exercises or cryotherapy group. Symptoms and functional limitations were evaluated at weeks 0, 2 and 6 using self-reported questionnaires (Disabilities of the Arm, Shoulder and Hand, Western Ontario Rotator Cuff, and Brief Pain Inventory), while acromiohumeral distance, shoulder strength and active range of motion were evaluated at weeks 0 and 2.

Results

Following interventions, both groups showed statistically significant improvements on symptoms and function at week 2 and week 6 compared with baseline. However, there was no significant group × time interaction. There was no time effect on acromiohumeral distance, shoulder strength and active range of motion, as well as no time × group interaction.

Conclusion

The results showed a statistically significant improvement in symptoms and function in both groups, but there was no difference between the short-term effect of a cryotherapy based-approach and a gradual reloading exercises programme.

Trial registration number

NCT02813304.

Population genealogy resource shows evidence of familial clustering for Alzheimer disease

OBJECTIVE

To show the potential of a resource consisting of a genealogy of the US record linked to National Veterans Health Administration (VHA) patient data for investigation of the genetic contribution to health-related phenotypes, we present an analysis of familial clustering of VHA patients diagnosed with Alzheimer disease (AD).

METHODS

Patients with AD were identified by the International Classification of Diseases code. The Genealogical Index of Familiality method was used to compare the average relatedness of VHA patients with AD with expected relatedness. Relative risks for AD were estimated in first- to fifth- degree relatives of patients with AD using population rates for AD.

RESULTS

Evidence for significant excess relatedness and significantly elevated risks for AD in relatives was observed; multiple pedigrees with a significant excess of VHA patients with AD were identified.

CONCLUSIONS

This analysis of AD shows the nascent power of the US Veterans Genealogy Resource, in early stages, to provide evidence for familial clustering of multiple phenotypes, and shows the utility of this VHA genealogic resource for future genetic studies.

Superior glenoid inclination and rotator cuff tears

BACKGROUND

The objectives of this study were to determine whether glenoid inclination (1) could be measured accurately on magnetic resonance imaging (MRI) using computed tomography (CT) as a gold standard, (2) could be measured reliably on MRI, and (3) whether it differed between patients with rotator cuff tears and age-matched controls without evidence of rotator cuff tears or glenohumeral osteoarthritis.

METHODS

In this comparative retrospective radiographic study, we measured glenoid inclination on T1 coronal MRI corrected into the plane of the scapula. We determined accuracy by comparison with CT and inter-rater reliability. We compared glenoid inclination between patients with full-thickness rotator cuff tears and patients aged >50 years without evidence of a rotator cuff tear or glenohumeral arthritis. An a priori power analysis determined adequate power to detect a 2° difference in glenoid inclination.

RESULTS

(1) In a validation cohort of 37 patients with MRI and CT, the intraclass correlation coefficient was 0.877, with a mean difference of 0° (95% confidence interval, -1° to 1°). (2) For MRI inclination, the inter-rater intraclass correlation coefficient was 0.911. (3) Superior glenoid inclination was 2° higher (range, 1°-4°, P < .001) in the rotator cuff tear group of 192 patients than in the control cohort of 107 patients.

CONCLUSIONS

Glenoid inclination can be accurately and reliably measured on MRI. Although superior glenoid inclination is statistically greater in those with rotator cuff tears than in patients of similar age without rotator cuff tears or glenohumeral arthritis, the difference is likely below clinical significance.

EXERCISE THERAPY IN THE NON-OPERATIVE TREATMENT OF FULL-THICKNESS ROTATOR CUFF TEARS: A SYSTEMATIC REVIEW

BACKGROUND

Although commonly prescribed, the evidence to support exercises therapy (ET) and conservative management for the treatment of full-thickness rotator cuff tears (FTT) is equivocal.

PURPOSE

The purpose of this systematic review of the literature was to determine the current level of evidence available for ET in the treatment of FTT and to provide a formal Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group of recommendation.

METHODS

Five databases were systematically searched to evaluate the effectiveness of ET for FTT. Inclusion criteria: experimental or observational studies of adults clinically diagnosed with FTT, or massive, or inoperable tears that contained a treatment group that received ET for FTT. Exclusion criteria included: history of surgical repair, concurrent significant trauma, neurological impairment, and level V studies. Articles were assessed for quality, the level of evidence (I - V) and GRADE of recommendation (A to F) was determined. Data extraction included: demographics, specific interventions, and outcomes.

RESULTS

One thousand, five-hundred and sixty-nine unique citations were identified, 35 studies were included: nine randomized controlled studies, six cohort studies, 15 case series and five case reports. There were 2010 shoulders in 1913 subjects with an average age of 64.2 years, 54% males, 73% of tears were > 1 cm and 37% were classified as massive. Based on studies that reported, >58% of tears were > 1 year and 73% were atraumatic. Of the non-operatively treated cohorts that reported the respective outcomes: 78% improved in pain (9/10 cohorts that reported statistically significant differences [stat-sig] p<0.05), 81% improved in ROM (14/14 cohorts that reported, met stat-sig), 85% improved in strength (7/8 cohorts that reported, met stat-sig), 84% improved in functional outcomes (17/17 cohorts that reported, met stat-sig). Dissatisfied outcomes occurred in 15% of patients, who then transitioned to surgery.

CONCLUSION

The current literature indicates GRADE B recommendation (moderate strength) to support the use of ET in the management of FTT. There is further need for well-designed randomized controlled trials.

LEVEL OF EVIDENCE

2a.

Evidence of an Inherited Predisposition for Spinal Cord Tumors

STUDY DESIGN

Retrospective study.

OBJECTIVES

To determine familial clustering of primary spinal cord tumors using a statewide genealogy database.

METHODS

The Utah Population Database (UPDB) was queried using ICD-Oncology (International Classification of Diseases for Oncology) codes for primary spinal cord tumors. The hypothesis of disproportionate familial clustering was tested using the Genealogical Index of Familiality (GIF). The relative risks (RRs) in relatives were calculated using the ratio of observed spinal cord tumors to expected spinal cord tumors in relatives using estimated rates from the UPDB. The related clusters of spinal cord cancer cases with a significant excess number of spinal cord cancer cases descending from a common founder pair were identified using internal UPDB rates.

RESULTS

The analysis of the GIF for individual with tumors of the spinal cord showed excess close and distant relatedness (case GIF = 3.82; control mean GIF = 2.68; P = .068). Excess relatedness for spinal cord cancers was observed when only more distant relationships were considered (P = .019). The RRs for spinal cord tumors were elevated in second- and third-degree relatives but this did not reach statistical significance (RR = 2.9, P = .15, and RR = 2.0, P = .14). Multiple extended pedigrees with a significant excess of spinal cord cancer cases among the descendants were identified.

CONCLUSIONS

The excess relatedness of tumor cases over controls in distant relationships, the higher RRs to distant relatives, and the discovery of high-risk pedigrees all suggest a familial predisposition to the development of spinal cord tumors.

Patients with a long-standing cuff tear in one shoulder have high rates of contralateral cuff tears: a study of patients with arthroscopically verified cuff tears 22 years ago

BACKGROUND

The prevalence of contralateral full-thickness cuff tears (FTTs) and cuff tear arthropathy (CTA) is presumed to be higher in patients with long-standing cuff tears than in those with newly diagnosed tears, but data are currently lacking.

METHODS

Sixty-one patients with 38 partial and 23 full-thickness tears of 1 shoulder at arthroscopy were examined with bilateral radiographs, ultrasound, and the Constant-Murley score at a mean of 22 years (range, 21-25 years) after arthroscopy.

RESULTS

The overall rate of full-thickness tears in the contralateral shoulder was 50.8%. In patients with a full-thickness tear and CTA (Hamada grade ≥2) in the index shoulder at follow-up, 18 of 20 (90%) had a contralateral full-thickness tear and 4 of 20 (20%) had CTA. In patients with a partial tear in the index shoulder at follow-up, 3 of 22 (13.6%) had a contralateral full-thickness tear and none had CTA. CTA changes were more common in patients with FTT and a previous acromioplasty (P < .001). The correlation between shoulders was 0.72 for the number of tendons with FTT (P <.001), 0.31 for the Hamada grade (P = .016), and 0.65 for the absolute Constant-Murley score (P <.001). The number of tendons with a full-thickness tear at follow-up was a risk factor (odds ratio, 3.28; 95% confidence interval, 1.67-6.44; P <.001) for a contralateral full-thickness tear. Patients with a partial or full-thickness tear in the contralateral shoulder had pain in 39.2% of cases.

CONCLUSION

Patients with long-standing cuff tears have high rates of contralateral cuff tears. The severity of the condition is strongly correlated between the shoulders. Patients with full-thickness tears and a previous acromioplasty have a significantly higher frequency of CTA than patients with cuff tears who had not undergone a previous acromioplasty.

Specific exercises for subacromial pain

Background and purpose - We have previously shown that specific exercises reduced the need for surgery in subacromial pain patients at 1-year follow-up. We have now investigated whether this result was maintained after 5 years and compared the outcomes of surgery and non-surgical treatment. Patients and methods - 97 patients were included in the previously reported randomized study of patients on a waiting list for surgery. These patients were randomized to specific or unspecific exercises. After 3 months of exercises the patients were asked if they still wanted surgery and this was also assessed at the present 5-year follow-up. The 1-year assessment included Constant-Murley score, DASH, VAS at night, rest and activity, EQ-5D, and EQ-VAS. All these outcome assessments were repeated after 5 years in 91 of the patients. Results - At the 5-year follow-up more patients in the specific exercise group had declined surgery, 33 of 47 as compared with 16 of 44 (p = 0.001) in the unspecific exercise group. The mean Constant-Murley score continued to improve between the 1- and 5-year follow-ups in both surgically and non-surgically treated groups. On a group level there was no clinically relevant change between 1 and 5 years in any of the other outcome measures regardless of treatment. Interpretation - This 5-year follow-up of a previously published randomized controlled trial found that specific exercises reduced the need for surgery in patients with subacromial pain. Patients not responding to specific exercises may achieve similar good results with surgery. These findings emphasize that a specific exercise program may serve as a selection tool for surgery.

Risk factors associated to bilateral rotator cuff tears

INTRODUCTION

Overuse, micro-traumas, and impingement, isolated or combined, are the more common etiological factors for rotator cuff tears. Metabolic disorders (diabetes, adiposity, hypercholesterolemia), hypertension, cigarette smoking and a genetic predisposition are considered risk factors. However, no study has compared the prevalence of these risk factors in subjects with bilateral and monolateral tears.

HYPOTHESIS

Controlateral tears can be observed in patients with symptomatic monolateral rotator cuff lesions, especially in those with comorbidities.

MATERIAL AND METHODS

In patients with symptomatic rotator cuff tear, the controlateral shoulders were evaluated by means of ultrasound imaging. Age, BMI, diabetes, hypercholesterolemia, hypertension, cigarette smoking, work habits were registered. Risk factors in subjects with bilateral tears were compared with those with monolateral lesions.

RESULTS

Of the 180 subjects recruited, 69 had a tear in the controlateral shoulder. Higher age and BMI values, heavy repetitive work and diabetes were significantly prevalent in these patients. At multivariate analysis, these factors were independently related to a higher probability to detect bilateral tears.

DISCUSSION

Metabolic risk factors are more heavily involved in presence of bilateral rotator cuff tears, in comparison to monolateral.

TYPE OF STUDY

Original study.

LEVEL OF PROOF

IV.

Shoulder activity level and progression of degenerative cuff disease

BACKGROUND

This study prospectively examined the relationship of direct and indirect measures of shoulder activity with the risks of tear progression and pain development in subjects with an asymptomatic degenerative rotator cuff tear.

METHODS

A cohort of asymptomatic degenerative rotator cuff tears was prospectively monitored annually, documenting tear size progression with ultrasound imaging and potential shoulder pain development. Shoulder activity level, self-reported occupational and physical demand level, and hand dominance were compared with risks of tear enlargement and future pain development.

RESULTS

The study monitored 346 individuals with a mean age of 62.1 years for a median duration of 4.1 years (interquartile range [IQR], 2.4-7.9 years). Tear enlargement was seen in 177 shoulders (51.2%), and pain developed in 161 shoulders (46.5%) over time. Tear presence in the dominant shoulder was associated with a greater risk of tear enlargement (hazard ratio, 1.40; P = .03) and pain development (hazard ratio, 1.63; P = .002). Shoulder activity level (P = .37) and occupational demand level (P = .62) were not predictive of tear enlargement. Occupational demand categories of manual labor (P = .047) and "in between" (P = .045) had greater risks of pain development than sedentary demands. The median shoulder activity score for shoulders that became painful was lower than for shoulders that remained asymptomatic (10.0 [IQR, 7.0-13.0] vs. 11.0 [IQR, 8.0-14.0], P = .02).

CONCLUSIONS

Tear enlargement and pain development in asymptomatic tears are more common with involvement of the dominant shoulder. Shoulder activity level is not related to tear progression risks. Pain development is associated with a lower shoulder activity level even though patients with higher occupational demands are more likely to develop pain.

Matrix Metalloproteases 1 and 3 Promoter Gene Polymorphism Is Associated With Rotator Cuff Tear

BACKGROUND

Studies suggest that the collagen degeneration and disordered arrangement of collagen fibers in rotator cuff tears are associated with an increase in activity of matrix metalloproteases 1 and 3 (MMP-1 and MMP-3), and that MMP activity may be in part genetically mediated. The degree to which this might be clinically relevant in patients with rotator cuff tears has not been well characterized.

QUESTIONS/PURPOSES

(1) Is genetic polymorphism of MMP-1 and MMP-3 associated with rotator cuff tears? (2) Are there haplotypes of MMP-1 and MMP-3 correlated with rotator cuff tears? (3) Compared with control subjects, do patients with rotator cuff tears have a higher proportion of relatives with the same disease?

METHODS

We evaluated 64 patients with full-thickness rotator cuff tears and 64 asymptomatic control subjects. Patients younger 65 years, with nontraumatic tears, were included. The tear or integrity of the rotator cuff tear was evaluated by MRI or ultrasonography in all individuals. The patients and control subjects were paired by age. MMP-1 and MMP-3 genotypes were determined using the PCR-restriction fragment length polymorphism assays.

RESULTS

Genetic polymorphisms in MMP-1 and MMP-3 are associated with rotator cuff tear, in which individuals with rotator cuff tears have associated genotypes 1G/2G (patients, 32 of 64 [50%], control subjects, 16 of 64 [25%]; odds ratio [OR], 4.8; 95% CI, 2.1-11.0; p < 0.001) and 2G/2G were at great risk (patients, 15 of 64 [23%], control subjects, seven of 64 [11%]; OR, 5.2; 95% CI,1.8-14.9; p < 0.001), and patients with rotator cuff tears were associated with a higher proportion of 2G allele distribution (62 of 128 [48%] versus 30 of 128 [23%]; p < 0.001). Patients with the 5A/5A genotype are at greater risk of rotator cuff tear (patients, 15 of 64 [23%]; control subjects, four of 64 [6%]; OR, 5.5; 95% CI, 1.4-20.9; p = 0.021), and there was higher 5A allele distribution in patients with rotator cuff tears (patients, 68 of 128 [53%]; control subjects, 52 of 128 [41%]; p = 0.045). Individuals with the haplotype 2G/5A were more likely to have rotator cuff tears develop (patients, 42 of 64 [66%]; control subjects, 17 of 64 [27%]; OR, 5.3; 95% CI, 2.5-11.3; p < 0.001). Patients with rotator cuff tears reported, in higher number, the existence of relatives who previously had treatment for rotator cuff tears (19 of 64 [30%] versus four of 64 [6%]; OR, 6.3; 95% CI, 2.0-19.9; p = 0.001).

CONCLUSIONS

The genetic polymorphism of MMP-1 and MMP-3 is associated with rotator cuff tear. Individuals with haplotype 2G/5A were more susceptible to rotator cuff tears in the population studied.

CLINICAL RELEVANCE

Knowledge of the genetic markers related to rotator cuff tears can enable identification of susceptible individuals and increase understanding of the pathogenesis of tendon degeneration.

Genetic and familial predisposition to rotator cuff disease: a systematic review

BACKGROUND

Rotator cuff disease is a common disorder leading to shoulder pain and loss of function. Its etiology in atraumatic cases is uncertain and is likely to extend beyond repetitive microtrauma or overuse. Our objective was to determine whether there is a genetic or familial predisposition to rotator cuff disease.

METHODS

A literature search of PubMed and Embase databases identified 251 citations. After review of the titles, abstracts, and full articles, 7 met our inclusion and exclusion criteria.

RESULTS

Four studies assessed familial predisposition to rotator cuff disease. One of these demonstrated that siblings of an individual with a rotator cuff tear were more likely to develop a full-thickness tear and more likely to be symptomatic. A 5-year follow-up showed that the relative risks were increased for the siblings to have a full-thickness tear, for a tear to progress in size, and for being symptomatic. Another study demonstrated that a significantly higher number of individuals with tears had family members with a history of tears or surgery than those without tears did. The other 3 studies investigated whether a genetic predisposition to rotator cuff disease exists and found significant association of haplotypes in DEFB1, FGFR1, FGF3, ESRRB, and FGF10 and 2 single-nucleotide polymorphisms within SAP30BP and SASH1.

CONCLUSION

Prior studies provide preliminary evidence for genetic and familial predisposition to rotator cuff disease. However, there is a lack of large genome-wide studies that can provide more definitive information and guide early detection of individuals at risk, prophylactic rehabilitation, and potential gene therapies and regenerative medicine interventions.

CURRENT CONCEPTS ON THE GENETIC FACTORS IN ROTATOR CUFF PATHOLOGY AND FUTURE IMPLICATIONS FOR SPORTS PHYSICAL THERAPISTS

CONTEXT

Recent advances within the field of genetics are currently changing many of the methodologies in which medicine is practiced. These advances are also beginning to influence the manner in which physical therapy services are rendered. Rotator cuff pathology is one of the most common diagnoses treated by the sports physical therapist. The purpose of this commentary is to educate sports physical therapists on the recent advances regarding how genetics influences rotator cuff pathology, including rotator cuff tears, and provide a perspective on how this information will likely influence post-operative shoulder rehabilitation in the near future.

EVIDENCE ACQUISITION

A comprehensive review of the literature was completed using the Medline database along with individual searches of relevant physical therapy, surgical, cell biology, and sports medicine journals. Search terms included: shoulder, rotator cuff pathology, genetics, apoptosis, and physical therapy. Search results were compiled and evaluated; relevant primary studies and review articles were gathered; the results from this comprehensive review are summarized here.

STUDY DESIGN

Clinical Commentary, Review of the Literature.

RESULTS

Recent advances within the understanding of rotator cuff pathology have further elucidated the cellular and molecular mechanisms associated with rotator cuff tears. There appears to be a hypoxic-induced apoptotic cellular pathway that contributes to rotator cuff tears. Activation of specific proteins termed matrix metalloproteinases appear to be involved in not only primary rotator cuff tears, but also may influence the re-tear rate after surgical intervention. Further advancements in the understanding of the cellular mechanisms contributing to rotator cuff tears and postoperative techniques to help prevent re-tears, may soon influence the methodology in which physical therapy services are provided to patients sustaining a rotator cuff injury.

CONCLUSIONS

At this time continued research is required to more fully develop a comprehensive understanding of the role of genetic variables both within primary rotator cuff tears and their influences on post-operative rehabilitation from rotator cuff repair surgery.

LEVEL OF EVIDENCE

Level 5.

Candidate gene approach identifies six SNPs in tenascin-C (TNC) associated with degenerative rotator cuff tears

Evidence for a heritable predisposition to rotator cuff tears (RCTs) is growing. Unrelated Caucasian individuals with surgically diagnosed full thickness RCTs (cases) and elderly Caucasian controls with intact rotator cuffs were screened for differences at the candidate genes: TNC, Col5A1, TIMP-1, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-13. A first cohort (59 cases; 32 controls) was genotyped with the Sequenom MassARRAY iPLEX system. Of 142 SNPs within about 67-kbp of the TNC gene, 30 were tested for differences in proportions between cases and controls. A second, matched cohort (96 patients; 44 controls) was also genotyped for the same 30 SNPs, but with the KASP™ genotyping technology. Combining the two cohorts and after Bonferroni correction, six SNPs were significantly associated with RCT. Compared to controls, RCT patients showed a significantly higher rate of homozygosity at rs72758637, rs7021589, and rs1138545; a significantly higher rate of heterozygosity at rs10759753, rs3789870, and rs7035322 and a higher minor allele frequency at rs3789870. Rs1138545, a missense SNP in exon10 might be of biological significance because it varies the amino acid sequence close to the TNC-FNIII5 domain. The FNIII5 domain binds multiple growth factors and co-ligates with integrins during tendon healing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:894-901, 2017.

Collagen fibrils in functionally distinct tendons have differing structural responses to tendon rupture and fatigue loading

In this study we investigate relationships between the nanoscale structure of collagen fibrils and the macroscale functional response of collagenous tissues. To do so, we study two functionally distinct classes of tendons, positional tendons and energy storing tendons, using a bovine forelimb model. Molecular-level assessment using differential scanning calorimetry (DSC), functional crosslink assessment using hydrothermal isometric tension (HIT) analysis, and ultrastructural assessment using scanning electron microscopy (SEM) were used to study undamaged, ruptured, and cyclically loaded samples from the two tendon types. HIT indicated differences in both crosslink type and crosslink density, with flexor tendons having more thermally stable crosslinks than the extensor tendons (higher TFmax of >90 vs. 75.1±2.7°C), and greater total crosslink density than the extensor tendons (higher t1/2 of 11.5±1.9 vs. 3.5±1.0h after NaBH4 treatment). Despite having a lower crosslink density than flexor tendons, extensor tendons were significantly stronger (37.6±8.1 vs. 23.1±7.7MPa) and tougher (14.3±3.6 vs. 6.8±3.4MJ/m(3)). SEM showed that collagen fibrils in the tougher, stronger extensor tendons were able to undergo remarkable levels of plastic deformation in the form of discrete plasticity, while those in the flexor tendons were not able to plastically deform. When cyclically loaded, collagen fibrils in extensor tendons accumulated fatigue damage rapidly in the form of kink bands, while those in flexor tendons did not accumulate significant fatigue damage. The results demonstrate that collagen fibrils in functionally distinct tendons respond differently to mechanical loading, and suggests that fibrillar collagens may be subject to a strength vs. fatigue resistance tradeoff.

STATEMENT OF SIGNIFICANCE

Collagen fibrils-nanoscale biological cables-are the fundamental load-bearing elements of all structural human tissues. While all collagen fibrils share common features, such as being composed of a precise quarter-staggered polymeric arrangement of triple-helical collagen molecules, their structure can vary significantly between tissue types, and even between different anatomical structures of the same tissue type. To understand normal function, homeostasis, and disease of collagenous tissues requires detailed knowledge of collagen fibril structure-function. Using anatomically proximate but structurally distinct tendons, we show that collagen fibrils in functionally distinct tendons have differing susceptibilities to damage under both tensile overload and cyclic fatigue loading. Our results suggest that the structure of collagen fibrils may lead to a strength versus fatigue resistance tradeoff, where high strength is gained at the expense of fatigue resistance, and vice versa.

Is thoracic spine posture associated with shoulder pain, range of motion and function? A systematic review

INTRODUCTION

Excessive thoracic kyphosis is considered a predisposing factor for shoulder pain, though there is uncertainty about the nature of the relationship between shoulder pain and thoracic spine posture. The aim of this systematic review was to investigate the relationship between thoracic kyphosis and shoulder pain, shoulder range of motion (ROM) and function.

METHODS

Two reviewers independently searched eight electronic databases and identified relevant studies by applying eligibility criteria. Sources of bias were assessed independently by two reviewers using a previously validated tool (Ijaz et al., 2013). Data were synthesised using a level of evidence approach (van Tulder et al., 2003).

RESULTS

Ten studies were included. Four studies were rated as low risk of bias, three at moderate risk of bias and three at high risk of bias. There is a moderate level of evidence of no significant difference in thoracic kyphosis between groups with and without shoulder pain. One study at high risk of bias demonstrated significantly greater thoracic kyphosis in people with shoulder pain (p < 0.05). There is a strong level of evidence that maximum shoulder ROM is greater in erect postures compared to slouched postures (p < 0.001), in people with and without shoulder pain.

CONCLUSIONS

Thoracic kyphosis may not be an important contributor to the development of shoulder pain. While there is evidence that reducing thoracic kyphosis facilitates greater shoulder ROM, this is based on single-session studies whose long-term clinical relevance is unclear. Higher quality research is warranted to fully explore the role of thoracic posture in shoulder pain.

Identification of a genetic variant associated with rotator cuff repair healing

BACKGROUND

A familial and genetic predisposition for the development of rotator cuff tearing has been identified. The purpose of this study was to determine if a familial predisposition exists for healing after rotator cuff repair and if the reported significant association with a single-nucleotide polymorphism (SNP) in the ESRRB gene is present in patients who fail to heal.

MATERIALS AND METHODS

The study recruited 72 patients undergoing arthroscopic rotator cuff repair for a full-thickness posterosuperior tear. Magnetic resonance imaging studies were performed at a minimum of 1 year postoperatively (average, 2.6 years). Healing failures were classified as lateral or medial. Self-reported family history of rotator cuff tearing data and genome-wide genotypes were available. Characteristics of cases with and without a family history of rotator cuff tearing were compared, and a comparison of the frequency of SNP 1758384 (in ESRRB) was performed between patients who healed and those who failed to heal.

RESULTS

Of the rotator cuff repairs, 42% failed to heal; 42% of patients reported a family history of rotator cuff tear. Multivariate regression analysis showed a significant association between familiality and overall healing failure (medial and lateral failures) (P = .036) and lateral failures independently (P = .006). An increased risk for the presence of a rare allele for SNP rs17583842 was present in lateral failures compared with those that healed (P = .005).

CONCLUSIONS

Individuals with a family history of rotator cuff tearing were more likely to have repair failures. Significant association of a SNP variant in the ESRRB gene was also observed with lateral failure.

Evidence for an Environmental and Inherited Predisposition Contributing to the Risk for Global Tendinopathies or Compression Neuropathies in Patients With Rotator Cuff Tears

Background:

Rotator cuff tearing has been found to be clinically associated with other tendinopathies and compression neuropathies; a significant excess of these phenotypes has been seen in patients with rotator cuff tears. It is unclear if the association is secondary to environmental or genetic influences.

Purpose:

To examine population-based data for comorbid association of rotator cuff tearing and tendinopathies and compression neuropathies and to determine whether the association extends to relatives of patients with rotator cuff tears, which could suggest a genetic contribution.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

The Utah Population Database (UPDB) contains health and genealogical data on over 2 million Utah residents. Current Procedural Terminology, Fourth Revision, codes (CPT 4) and International Classification of Diseases, Ninth Revision, codes (ICD-9) entered in patient records were used to identify patients with rotator cuff tearing and with comorbid tendinopathies and compression neuropathies. We tested the hypothesis of excess familial clustering of these other phenotypes with rotator cuff tearing using a well-established method (estimation of relative risks) in the overall study group of rotator cuff patients (N = 1889).

Results:

Significantly elevated risk for elbow, hand/wrist, foot/ankle, knee, and hip tendinopathies, as well as for all tendinopathies and compression neuropathies, was observed in rotator cuff tear cases themselves (P < 2.8e^–13), in their spouses (P < .02), and in their first-degree relatives (P < 5.5e^–4). A significant excess of elbow (P = .01), foot/ankle (P = .04), and all tendinopathies (P = 3.1e^–3) was also observed in second-degree relatives, and a significant excess of compression neuropathies (P = .03) was observed in third-degree relatives.

Conclusion:

The current study shows strong evidence of familial clustering of rotator cuff tearing with other tendinopathies and with compression neuropathy. Observed increased risks in spouses and first-degree relatives supports shared environmental risk factors for rotator cuff tearing, most tendinopathies, and compression neuropathies. Increased risks to third-degree relatives for compression neuropathy suggest an association of these phenotypes that may have a shared genetic etiology.

Utility of features of the patient's history in the diagnosis of atraumatic shoulder pain: a systematic review

BACKGROUND

Whereas physical examination tests for shoulder disorders have numeric values that describe the utility of the test and its effect on the probability of having a diagnosis, this information is lacking for elements of the history. The purpose of this study was to conduct a systematic review of the literature to determine numeric data (sensitivity, specificity, predictive values, and likelihood or odds ratios) for elements of the history with regard to diagnoses in patients with chronic atraumatic shoulder pain.

METHODS

We performed a systematic review to extract information from the existing literature regarding the numeric utility of different features of the patient history as they pertain to chronic atraumatic shoulder pain. Data sources were MEDLINE through PubMed (1946-January 2012) and EMBASE through Ovid (1980-January 2012).

RESULTS

Twenty-one studies met inclusion criteria. A diagnosis of rotator cuff tear was more likely with a history of hypercholesterolemia, having a relative with rotator cuff disease, excessive lifting, above-shoulder work, hand-held vibration work, or age older than 60 years. Acromioclavicular arthritis was more likely in weightlifters. Glenohumeral arthritis was more likely if the patient has a history of prior dislocation, age >75 years, or a diagnosis of knee osteoarthritis. Adhesive capsulitis was more likely with a history of diabetes or thyroid disorder. Posterior labral tear was more likely in football players.

CONCLUSIONS

The numeric values for the utility of these history features will help establish numeric probabilities for diagnoses in patients with shoulder pain.

Genome-wide association study for rotator cuff tears identifies two significant single-nucleotide polymorphisms

BACKGROUND

The precise etiology of rotator cuff disease is unknown, but prior evidence suggests a role for genetic factors. Limited data exist identifying specific genes associated with rotator cuff tearing. The purpose of this study was to identify specific genes or genetic variants associated with rotator cuff tearing by a genome-wide association study with an independent set of rotator cuff tear cases.

MATERIALS AND METHODS

A set of 311 full-thickness rotator cuff tear cases genotyped on the Illumina 5M single-nucleotide polymorphism (SNP) platform were used in a genome-wide association study with 2641 genetically matched white population controls available from the Illumina iControls database. Tests of association were performed with GEMMA software at 257,558 SNPs that compose the intersection of Illumina SNP platforms and that passed general quality control metrics. SNPs were considered significant if P < 1.94 × 10(-7) (Bonferroni correction: 0.05/257,558).

RESULTS

Tests of association revealed 2 significantly associated SNPs, one occurring in SAP30BP (rs820218; P = 3.8E-9) on chromosome 17q25 and another occurring in SASH1 (rs12527089; P = 1.9E-7) on chromosome 6q24.

CONCLUSIONS

This study represents the first attempt to identify genetic factors influencing rotator cuff tearing by a genome-wide association study using a dense/complete set of SNPs. Two SNPs were significantly associated with rotator cuff tearing, residing in SAP30BP on chromosome 17 and SASH1 on chromosome 6. Both genes are associated with the cellular process of apoptosis. Identification of potential genes or genetic variants associated with rotator cuff tearing may help in identifying individuals at risk for the development of rotator cuff tearing.