title: The effect of lateral epicondylosis on upper limb mechanical parameters.
abstract: BACKGROUND
  Lateral epicondylosis is a prevalent and costly musculoskeletal disorder characterized by degeneration of the common extensor tendon origin at the lateral epicondyle. Grip strength is commonly affected due to lateral epicondylosis. However, less is known about the effect of lateral epicondylosis on other functional parameters such as ability to react to rapid loading.
  
  
  METHODS
  Twenty-nine lateral epicondylosis participants and ten controls participated in a case-control study comparing mechanical parameters (mass, stiffness and damping), magnetic resonance imaging signal intensity and grip strength of injured and uninjured limbs. A mixed effects model was used to assess the effect of dominance and injury on mechanical parameters and grip strength.
  
  
  RESULTS
  Significant effect of injury and dominance was observed on stiffness, damping and grip strength. An injured upper limb had, on average, 18% less stiffness (P<0.01, 95% CI [9.8%, 26%]), 21% less damping (P<0.01, 95% CI [11%, 31%]) and 50% less grip strength (P<0.01, 95% CI [37%, 61%]) than an uninjured upper limb. The dominant limb had on average 15% more stiffness (P<0.01, 95% CI [8.0%, 23%], 33% more damping (P<0.01, 95% CI [22%, 45%]), and 24% more grip strength (P<0.01, 95% CI [6.6%, 44%]) than the non-dominant limb.
  
  
  CONCLUSIONS
  Lower mechanical parameters are indicative of a lower capacity to oppose rapidly rising forces and quantify an important aspect of upper limb function. For individuals engaged in manual or repetitive activities involving the upper limb, a reduction in ability to oppose these forces may result in increased risk for injury or recurrence.
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin, Madison, 2107 Engineering Centers Building, 1550 Engineering Dr, Madison, WI 53706, USA. amrishc@gmail.com
authors.forename: Amrish O
authors.initials: AO
authors.lastname: Chourasia
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Buhr
authors.forename: David P
authors.initials: DP
authors.lastname: Rabago
authors.forename: Richard
authors.initials: R
authors.lastname: Kijowski
authors.forename: Mary E
authors.initials: ME
authors.lastname: Sesto
mesh_terms: D000328:Adult; D001132:Arm / Q000503:physiopathology*; D003198:Computer Simulation; D055119:Elastic Modulus; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009929:Organ Size; D013314:Stress, Mechanical; D013716:Tennis Elbow / Q000503:physiopathology*; D014783:Viscosity