Joint hypermobility and its association with self-reported knee health: A cross-sectional study of healthy Australian adults.

Aim: The primary aim of this study was to determine the association between generalized joint hypermobility (GJH), knee-specific hypermobility (KSH) and self-reported knee health in an Australian population. Secondary aims included elucidating ethnic/gender differences in GJH/KSH prevalence and knee health, and identifying KSH using a novel knee extension range of motion cut-off method.

Method: Knee extension range, Beighton score, and 5 domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS) were collected from adults aged 18-101 years self-identifying as healthy, and were grouped by ethnicity and gender. Two established Beighton score criteria and 1 novel knee extension range cut-off method were used to determine GJH and KSH respectively. Point-biserial correlation tested the associations between GJH/KSH and KOOS. Differences in GJH/KSH prevalence and knee health between ethnic/gender groups were determined with the Chi-squared test.

Results: Of 732 participants (50% male), 80.3% were Caucasian. No correlations were found between GJH and KOOS while a very weak correlation was found between KSH and 1 KOOS domain (r > -.30; P = .04). Prevalence of GJH was higher in non-Caucasians (17.4% vs 5.6%, P < .001) and females (4.4% vs 1.1%, P = .007). Prevalence of KSH between ethnic and gender groups was not significantly different (P = .50 and P = .69 respectively). Non-Caucasians scored higher (better) in all KOOS domains than Caucasians (all P < .05).

Conclusion: Those who met the age- and gender-specific criteria for GJH/KSH did not report worse knee health than their non-hypermobile counterparts. Clinicians can assure individuals who exhibit GJH/KSH that these are not associated with lower knee health and function.