title: Relationship of serum relaxin to generalized and trapezial-metacarpal joint laxity.
abstract: OBJECTIVE
  The reproductive hormone relaxin acts to loosen pelvic ligaments in preparation for childbirth and is thought to be a mediator of joint laxity. The purpose of this study was to evaluate the correlation of serum relaxin with radiographic laxity at the trapezial-metacarpal joint and with generalized joint laxity.
  
  
  METHODS
  We enrolled 289 healthy subjects prospectively. Participants completed a demographic questionnaire and were examined for generalized joint hypermobility using the Beighton-Horan scale. Stress radiographs of the trapezial-metacarpal joint were obtained in 163 subjects (56%). Blood samples were collected, and serum relaxin was measured for 287 subjects using enzyme-linked immunosorbent assay for human relaxin-2.
  
  
  RESULTS
  The mean serum relaxin level among all subjects was 1.84 pg/mL (range, 0-45.25 pg/mL). Relaxin was not detectable in 166 of 287 samples, whereas the mean serum relaxin level among the 121 subjects with a detectable relaxin level (of 287 total relaxin samples) was 4.37 pg/mL (range, 0.46-45.25 pg/mL). Mean trapezial-metacarpal subluxation ratio scores were higher among those with a detectable relaxin level compared to those without a detectable relaxin level (0.34 vs 0.30 pg/mL). The average Beighton-Horan laxity score was 1.8 (range, 0-9). There was no correlation between generalized joint laxity measures and serum relaxin levels.
  
  
  CONCLUSIONS
  In a large volunteer population, we demonstrated a relationship between circulating relaxin and trapezial-metacarpal joint laxity. However, we were unable to show a direct link between serum relaxin and generalized joint laxity.
  
  
  METHODS
  Prognostic II.
authors.affiliation: Department of Orthopaedic Surgery and Department of Community Medicine and Health Care, University of Connecticut Health Center, Farmington, CT 06030-4038, USA. jmwolf@uchc.edu
authors.forename: Jennifer Moriatis
authors.initials: JM
authors.lastname: Wolf
authors.forename: Allison E
authors.initials: AE
authors.lastname: Williams
authors.forename: Steven
authors.initials: S
authors.lastname: Delaronde
authors.forename: Robin
authors.initials: R
authors.lastname: Leger
authors.forename: Kari B
authors.initials: KB
authors.lastname: Clifton
authors.forename: Karen B
authors.initials: KB
authors.lastname: King
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000097:blood* / Q000000981:diagnostic imaging*; D016015:Logistic Models; D008297:Male; D008662:Metacarpophalangeal Joint / Q000000981:diagnostic imaging* / Q000502:physiology; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D012016:Reference Values; D012065:Relaxin / Q000097:blood*; D012680:Sensitivity and Specificity; D051222:Trapezium Bone / Q000000981:diagnostic imaging / Q000502:physiology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D012065:Relaxin