Hip Instability in Ballet Dancers: A Narrative Review.

BACKGROUND: Dancers possess a large degree of hip range of motion that results from a combination of innate and acquired osseous morphology and permissive soft tissues. Generalized hypermobility in dancers may predispose them to a spectrum of hip instability. The objective of this narrative review is to discuss the anatomical characteristics, pathogenesis, risk factors, clinical signs and symptoms, management, and outcomes of hip instability treatments in dancers.
Methods: A retrospective search was performed beginning November 1, 2017, for English language articles regarding hip stability in the dancer. Key words used included but were not limited to: dance(r), ballet, hip, hypermobility, range of motion, instability, microinstability, and laxity. PubMed, Scopus, and MEDLINE databases were used.
Results: Forty-three studies were analyzed. Groin pain was found to be the most common presenting symptom of hip instability. A variety of impingement and instability signs may be elicited during physical examination. Hypermobility is frequently observed and is thought to be a necessity for participation in elite levels of ballet. Radiographs and advanced planar imaging (magnetic resonance imaging and computed tomography) should be scrutinized to evaluate for dysplasia, cam, pincer, subspine, and rotational morphologies. Dysplasia (low volume acetabulum), cam morphology, femoral retroversion, and coxa valga are common findings in the ballet dancers' hip. Labral injuries and ligamentum teres tears are common and may potentiate instability in the hip. Management options include education, oral non-opioid medications, activity modification, exercise prescription, and surgery. Reported outcomes of these treatments in ballet are limited.
Conclusion: Hip hypermobility is prevalent in the ballet population and is a clear advantage. However, it may increase the risk of instability. It is important to identify the multifactorial osseous and soft tissue etiology of hip or groin pain in dancers. Practitioners should have a high level of suspicion for hip instability in the dancer presenting with hip pain and treat accordingly. There is a significant need for increased quantity and quality of investigation into the outcomes of treatment for hip instability in the dancer.

Interrater and Intrarater Reliability of the Beighton Score: A Systematic Review.

BACKGROUND: The Beighton score is commonly used to assess the degree of hypermobility in patients with hypermobility spectrum disorder. Since proper diagnosis and treatment in this challenging patient population require valid, reliable, and responsive clinical assessments such as the Beighton score, studies must properly evaluate efficacy and effectiveness. PURPOSE: To succinctly present a systematic review to determine the inter- and intrarater reliability of the Beighton score and the methodological quality of all analyzed studies for use in clinical applications. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: A systematic review of the MEDLINE, Embase, CINAHL, and SPORTDiscus databases was performed. Studies that measured inter- or intrarater reliability of the Beighton score in humans with and without hypermobility were included. Non-English, animal, cadaveric, level 5 evidence, and studies utilizing the Beighton score self-assessment version were excluded. Data were extracted to compare scoring methods, population characteristics, and measurements of inter- and intrarater reliability. Risk of bias was assessed with the COSMIN (Consensus-Based Standards for the Selection of Health Measurement Instruments) 2017 checklist. RESULTS: Twenty-four studies were analyzed (1333 patients; mean ± SD age, 28.19 ± 17.34 years [range, 4-71 years]; 640 females, 594 males, 273 unknown sex). Of the 24 studies, 18 reported raters were health care professionals or health care professional students. For interrater reliability, 5 of 8 (62.5%) intraclass correlation coefficients and 12 of 19 (63.2%) kappa values were substantial to almost perfect. Intrarater reliability was reported as excellent in all studies utilizing intraclass correlation coefficients, and 3 of the 7 articles using kappa values reported almost perfect values. Utilizing the COSMIN criteria, we determined that 1 study met "very good" criteria, 7 met "adequate," 15 met "doubtful," and 1 met "inadequate" for overall risk of bias in the reliability domain. CONCLUSION: The Beighton score is a highly reliable clinical tool that shows substantial to excellent inter- and intrarater reliability when used by raters of variable backgrounds and experience levels. While individual components of risk of bias among studies demonstrated large discrepancy, most of the items were adequate to very good.

An Injury Prevention Program for Professional Ballet: A Randomized Controlled Investigation.

BACKGROUND: Few investigations have examined dance-specific injury prevention programs (IPPs), and no published randomized controlled trials are available that evaluate IPPs for dance. HYPOTHESIS: The implementation of an IPP will significantly reduce the risk of injury in professional ballet dancers. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: A randomized controlled trial was designed that entailed a superiority model for the intervention group. All professional dancers from a single ballet company were eligible to participate. Randomization and allocation were performed before the start of the season. The control group practiced and performed without change to preexisting standard operating practice. The IPP group was instructed to perform a 30-minute exercise program 3 times per week over the 52-week study period. Injuries were recorded. Standard continuous and categorical data comparisons and correlations were used. Cox proportional hazards regression models for recurrent failures were used wherein the hazard ratio indicates the relative likelihood of injury in the control versus intervention groups. RESULTS: Of the 52 eligible dancers, 75% (n = 39) participated. Of these 39 dancers, 19 (9 males, 10 females; mean age, 26.6 ± 4.0 years) were randomized to the control group and 20 (11 males, 9 females; mean age, 25.1 ± 5.1 years) to the IPP group. No significant (P > .05) difference was found in baseline demographics between groups. A total of 116 injuries were recorded for the entire study population (49 IPP; 67 control). Traumatic and chronic injuries accounted for 54% and 46% of injuries, respectively. The injury rate was 82% less (IPP hazard ratio, 0.18; z = -2.29; P = .022) in the IPP group after adjustment for confounding variables, and time between injuries was 45% longer (IPP hazard ratio, 0.55; z = -2.20; P = .028) than for controls. CONCLUSION: The present study is the first prospective randomized controlled investigation of an IPP for professional ballet. The results showed an 82% decrease in injury rate for the intervention group and an extended period from previous injury to subsequent injury. REGISTRATION: NCT04110002 (ClinicalTrials.gov identifier).

High Prevalence of Connective Tissue Gene Variants in Professional Ballet.

BACKGROUND: There is a high prevalence of hypermobility spectrum disorder (HSD) in dancers. While there is no known genetic variant for HSD, hypermobile Ehlers-Danlos syndrome is a genetic disorder that exists within HSD. There are many connective tissue disorders (CTDs) with known (and unknown) genes associated with hypermobility. Hypermobility has distinct advantages for participation in flexibility sports, including ballet. PURPOSE: To determine the prevalence of gene variants associated with hypermobility in a large professional ballet company. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: In this cross-sectional investigation, 51 professional male and female dancers from a large metropolitan ballet company were eligible and offered participation after an oral and written informed consent process. Whole blood was obtained from peripheral venipuncture, and DNA was isolated. Isolated DNA was subsequently enriched for the coding exons of 60 genes associated with CTD that included hypermobility as a phenotype, including Ehlers-Danlos syndromes, osteogenesis imperfecta, Marfan syndrome, and others. Genes were targeted with hybrid capture technology. Prepared DNA libraries were then sequenced with next-generation sequencing technology. Genetic database search tools (Human Gene Mutation Database and e!Ensembl, http://useast.ensembl.org/ ) were used to query specific variants. Descriptive statistics were calculated. RESULTS: Of 51 dancers, 32 (63%) agreed to participate in DNA analysis (mean ± SD age, 24.3 ± 4.4 years; 18 men, 14 women). Twenty-eight dancers had at least 1 variant in the 60 genes tested, for an 88% prevalence. A total of 80 variants were found. A variant in 26 of the 60 genes was found in at least 1 dancer. Among the 28 dancers with variants, 16 were found in the TTN gene; 10 in ZNF469; 5 in RYR1; 4 in COL12A1; 3 in ABCC6 and COL6A2; 2 in ADAMTS2, CBS, COL1A2, COL6A3, SLC2A10, TNC, and TNXB; and 1 in ATP6V0A2, B4GALT7, BMP1, COL11A1, COL5A2, COL6A1, DSE, FBN1, FBN2, NOTCH1, PRDM5, SMAD3, and TGFBR1. Nine variants found in this population have never been reported. No identified variant was identical to any other variant. No identified variant was known to be disease causing. In the general population, the prevalence of each variant ranges from never reported to 0.33%. In the study population, the prevalence of each variant was 3.13%. There was no association between hypermobility scores and genetic variants. CONCLUSION: Genetic variants in CTD-associated genes are highly prevalent (88%) in professional ballet dancers. This may significantly account for the high degree of motion in this population.

Brake Reaction Time After Hip Arthroscopy for Femoroacetabular Impingement and Labral Tear.

PURPOSE: To determine if a difference exists in brake reaction time (BRT) before and after hip arthroscopy for femoroacetabular impingement (FAI) and labral tear compared with age- and gender-matched controls. METHODS: Consecutive adult subjects undergoing primary hip arthroscopy were eligible for this prospective investigation. Individuals with symptomatic FAI and labral tear that underwent hip arthroscopy with minimum 8 weeks follow-up were included. BRT was measured using the RT-2S reaction time tester a maximum of 6 weeks preoperatively and every 2 weeks postoperatively for 8 weeks. Sit-to-stand test (STST) was measured at each BRT testing session. An age- and gender-matched control group without hip or lower extremity symptoms were selected and completed both BRT and STST. Continuous pre- and postoperative BRT values were compared with Mann-Whitney and analyses of variance. Association of BRT and STST tests was performed with Spearman correlation. An a priori sample size calculation determined that minimally 18 subjects per group (surgery group vs control group) were necessary to detect, with 80% power (difference of 0.2 seconds in BRT). RESULTS: Nineteen subjects (age 37.1 ± 12.7 years, 10 women, 11 right hip) were analyzed. All subjects underwent arthroscopic labral repair and FAI correction. There was no difference between preoperative (604 ± 148 milliseconds [ms]) and postoperative (608 ms 2 weeks; 566 ms 4 weeks; 559 ms 6 weeks; 595 ms 8 weeks) BRT. There was no difference between controls and subjects at any time point. There was a strong negative correlation between BRT and STST preoperatively and at 4 and 6 weeks postoperatively and a moderate negative correlation at 2 weeks postoperatively. CONCLUSIONS: After hip arthroscopy for FAI and labral tear, BRT is not different from preoperative values or that of controls. In addition, BRT had a significant correlation with STST in the first 6 weeks after surgery. LEVEL OF EVIDENCE: Level II, diagnostic, prospective.

Augmented reality telementoring (ART) platform: a randomized controlled trial to assess the efficacy of a new surgical education technology.

BACKGROUND: Laparoscopic skills training has evolved over recent years. However, conveying a mentor's directions using conventional methods, without realistic on-screen visual cues, can be difficult and confusing. To facilitate laparoscopic skill transference, an augmented reality telementoring (ART) platform was designed to overlay the instruments of a mentor onto the trainee's laparoscopic monitor. The aim of this study was to compare the effectiveness of this new teaching modality to traditional methods in novices performing an intracorporeal suturing task. METHODS: Nineteen pre-medical and medical students were randomized into traditional mentoring (n = 9) and ART (n = 10) groups for a laparoscopic suturing and knot-tying task. Subjects received either traditional mentoring or ART for 1 h on the validated fundamentals of laparoscopic surgery intracorporeal suturing task. Tasks for suturing were recorded and scored for time and errors. Results were analyzed using means, standard deviation, power regression analysis, correlation coefficient, analysis of variance, and student's t test. RESULTS: Using Wright's cumulative average model (Y = aX (b)) the learning curve slope was significantly steeper, demonstrating faster skill acquisition, for the ART group (b = -0.567, r (2) = 0.92) than the control group (b = -0.453, r (2) = 0.74). At the end of 10 repetitions or 1 h of practice, the ART group was faster versus traditional (mean 167.4 vs. 242.4 s, p = 0.014). The ART group also had fewer fails (8) than the traditional group (13). CONCLUSION: The ART Platform may be a more effective training technique in teaching laparoscopic skills to novices compared to traditional methods. ART conferred a shorter learning curve, which was more pronounced in the first 4 trials. ART reduced the number of failed attempts and resulted in faster suture times by the end of the training session. ART may be a more effective training tool in laparoscopic surgical training for complex tasks than traditional methods.