Correlation between the elbow ulnar collateral ligament and

Correlation between the elbow ulnar collateral ligament and generalized joint hypermobility in young adults Kaylee Fichthorn, SPT & Lacy Mroz, SPT Florida Gulf Coast University, Department of Rehabilitation Sciences, Fort Myers, FL, USA Introduction Results Joint hypermobility is largely understood as a dysfunction of collagen fibers within connective tissues, allowing for a range of motion markedly increased over validated normal values. Generalized Joint Hypermobility (GJH) is defined using a Beighton score of ≥ 5/9. Previous studies used microscopic imaging to determine these relationships, and there has yet to be a published study looking into the correlation between the sonographically determined characteristics of ligaments and GJH. Participant Demographics: Objective To determine the relationship between the length and width of the anterior bundle of the Ulnar Collateral Ligament (UCL) of the elbow and GJH. Methods Data Analysis The sample was composed of 229 females (80. 6%) and 55 males (19. 4%). The average of participants was 19. 01 +/- 1. 24 (mean +/- standard deviation; range 18 -25). Most participants identified as Caucasian/White (193/284; 68. 0%), Hispanic (33/284; 11. 6%), or Black/African American (2/2844; 8. 5%). Remaining participants (34/284; 11. 9%) identified as more than one ethnicity or as an ethnicity that differed from those listed above (e. g. Asian, Indian, or Pacific Islander). The majority of participants were righthanded (245/284; 86. 0%), some were left-handed (34/284; 12. 0%) or ambidextrous (4/284; 1. 4%). Mean values for UCL thickness and joint gap under valgus stress for each elbow Anterior Bundle Thickness of UCL in cm Right Width of Humeroulnar Joint in cm Left Right Left Rest . 339 Rest . 341 Rest . 224 Rest . 225 Valgus . 338 Valgus . 346 Valgus . 229 Valgus . 240 UCL thickness at rest moderately correlated with UCL thickness under valgus force : - Undergraduate students enrolled in Human Anatomy & Physiology with lab I (A&P) classes at Florida Gulf Coast University completed anonymous self-response surveys and Beighton score assessments. Right Elbow: r =. 530, p <. 001 Left Elbow r=. 491, p <. 001 Valgus correlations between elbows: - Ultrasound images were obtained of both right and left medial elbow joints at rest and under gravity induced valgus stress. UCL thickness under valgus r=. 414, p <. 001 Joint width under valgus r=. 315, p <. 001 - For each image, measurements were taken of UCL anterior bundle midsubstance thickness and humeroulnar joint gap width. Joint Characteristics and Hypermobility Joint Gap Correlation to Hypermobility Variables - Data collection took place between October 2018 and January 2019. Collection rounds corresponded with A&P curricular education on the general structure and function of joints and range of motion. Beighton GJH Elbow Hypermobility r=. 147 p=. 020 None Right Elbow Under Valgus Force r=. 129; p=. 044 None At Rest Left Elbow None Under Valgus Force r =. 158; p=. 044 F=. 4889; p=. 028 None Example Image Demonstrating Landmarks ➢Joint gapping weakly correlated to GJH and Beighton ➢UCL Thickness not correlated to any hypermobility variable ➢Elbow hypermobility not correlated to any joint characteristic Our Image: At Rest Our Image: Valgus Force Applied References: See Handout with Reference List - Pearson correlations: relationship between medial elbow joint characteristics 1) at rest and under valgus force 2) between right and left elbows and 3) in relationship to Beighton scores - Paired T-test: whether valgus load had a significant effect on UCL thickness or joint width. - Multivariate analyses of variance (MANOVAs): medial elbow joint characteristics and 1) GJH and 2) elbow hypermobility. - Chi-square tests: 1) the relationship between right and left elbow hypermobility and 2) the relationship between elbow hypermobility and GJH. Discussion - The mean width of the humeroulnar joint gap of our participants support results from previous studies - The width of the anterior bundle of the UCL has been reported between 4 and 7. 6 mm. Our measurements come in lower. These studies regarding UCL anterior bundle thickness are comprised primarily of cadaver studies. - Elbow hypermobility was highly correlated with overall Beighton score and with subdivided Beighton scoring into GJH and LJH categories. - We found no significant difference in anterior bundle thickness or medial elbow joint gapping in hypermobile elbows versus normal. - Our results show different relationships between the joint width of right and left elbows. - Many studies have reported differences between dominant and non-dominant arms. These studies focused on overhead throwing athletes. - The differing relationships between elbows require further explanation. The role of the common flexor tendon and hand dominance may be an important consideration. Conclusions - Hypermobility in one elbow strongly related to hypermobility in the other - No significant difference in UCL anterior bundle thickness or joint width in participants with elbow hypermobility and those without - Beighton Score and GJH are not strongly associated with changes in medial elbow joint characteristics

Introduction Joint hypermobility is largely understood as a dysfunction of collagen fibers within connective tissues, allowing for a range of motion markedly increased over validated normal values. – Generalized Joint Hypermobility (GJH) is defined using a Beighton score of ≥ 5/9. – Previous studies used microscopic imaging to determine these relationships, and there has yet to be a published study looking into the correlation between the sonographically determined characteristics of ligaments and GJH. –

Objective To determine the relationship between the length and width of the anterior bundle of the Ulnar Collateral Ligament (UCL) of the elbow and GJH.

Methods - Undergraduate students enrolled in Human Anatomy & Physiology with lab I (A&P) classes at Florida Gulf Coast University completed anonymous self-response surveys and Beighton score assessments. - Ultrasound images were obtained of both right and left medial elbow joints at rest and under gravity induced valgus stress. - For each image, measurements were taken of UCL anterior bundle midsubstance thickness and humeroulnar joint gap width. - Data collection took place between October 2018 and January 2019. Collection rounds corresponded with A&P curricular education on the general structure and function of joints and range of motion.

Example Image Demonstrating Landmarks Our Image: At Rest Our Image: Valgus Force Applied

Results Participant Demographics: The sample was composed of 229 females (80. 6%) and 55 males (19. 4%). The average of participants was 19. 01 +/1. 24 (mean +/- standard deviation; range 18 -25). Most participants identified as Caucasian/White (193/284; 68. 0%), Hispanic (33/284; 11. 6%), or Black/African American (2/2844; 8. 5%). Remaining participants (34/284; 11. 9%) identified as more than one ethnicity or as an ethnicity that differed from those listed above (e. g. Asian, Indian, or Pacific Islander). The majority of participants were right-handed (245/284; 86. 0%), some were left-handed (34/284; 12. 0%) or ambidextrous (4/284; 1. 4%). Mean values for UCL thickness and joint gap under valgus stress for each elbow Anterior Bundle Thickness of UCL in cm Right Width of Humeroulnar Joint in cm Left Right Left Rest . 339 Rest . 341 Rest . 224 Rest . 225 Valgus . 338 Valgus . 346 Valgus . 229 Valgus . 240 UCL thickness at rest moderately correlated with UCL thickness under valgus force : Right Elbow: r =. 530, p <. 001 Left Elbow r=. 491, p <. 001 Valgus correlations between elbows: UCL thickness under valgus r=. 414, p <. 001 Joint width under valgus r=. 315, p <. 001

Results Joint Characteristics and Hypermobility Joint Gap Correlation to Hypermobility Variables Right Elbow Left Elbow Beighton GJH Elbow Hypermobility r=. 147 p=. 020 None Under Valgus Force r=. 129; p=. 044 None At Rest None Under Valgus Force r =. 158; p=. 044 F=. 4889; p=. 028 None Joint gapping weakly correlated to GJH and Beighton ➢ UCL Thickness not correlated to any hypermobility variable ➢ Elbow hypermobility not correlated to any joint characteristic ➢

Data Analysis - Pearson correlations: relationship between medial elbow joint characteristics 1) at rest and under valgus force 2) between right and left elbows and 3) in relationship to Beighton scores - Paired T-test: whether valgus load had a significant effect on UCL thickness or joint width. - Multivariate analyses of variance (MANOVAs): medial elbow joint characteristics and 1) GJH and 2) elbow hypermobility. - Chi-square tests: 1) the relationship between right and left elbow hypermobility and 2) the relationship between elbow hypermobility and GJH.

Discussion - The mean width of the humeroulnar joint gap of our participants support results from previous studies - The width of the anterior bundle of the UCL has been reported between 4 and 7. 6 mm. Our measurements come in lower. These studies regarding UCL anterior bundle thickness are comprised primarily of cadaver studies. - Elbow hypermobility was highly correlated with overall Beighton score and with subdivided Beighton scoring into GJH and LJH categories. - We found no significant difference in anterior bundle thickness or medial elbow joint gapping in hypermobile elbows versus normal. - Our results show different relationships between the joint width of right and left elbows. - Many studies have reported differences between dominant and non-dominant arms. These studies focused on overhead throwing athletes. - The differing relationships between elbows require further explanation. The role of the common flexor tendon and hand dominance may be an important consideration.

Conclusions - Hypermobility in one elbow strongly related to hypermobility in the other - No significant difference in UCL anterior bundle thickness or joint width in participants with elbow hypermobility and those without - Beighton Score and GJH are not strongly associated with changes in medial elbow joint characteristics

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