SHORT STEP KNEE OSTEOARTHRITIS: A BEGINNERS GUIDE TO RUNNING POST ACLR

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Collin Douglas Bowersock (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Introduction: Post anterior cruciate ligament reconstruction (ACLR), individuals are 3-4x more likely to develop knee osteoarthritis (OA). Increased knee joint loads, and knee joint loading characteristics have been associated with knee OA. Specifically, peak loads, cumulative loads, and loading rate loads about the knee have been associated with the onset and progression of knee OA. Running increases the magnitude of these loads and an estimated 90% of individual's participant in lower levels of activity such as running post ACLR. Changes in cartilage morphology that are seen as early as 4 months post ACL injury may suggest the cartilages inability to manage high cyclical loads associated with running. Thus, promoting interventions to decrease joint loads during running post ACLR may prevent or impede degenerative joint changes. Decreasing step length has been shown to decrease knee forces within the healthy population but due to gait changes seen post ACLR, it is unclear if these reductions will be seen among the ACLR population. Between limb kinematic differences have also been seen, but no study has compared joint loads between limbs post ACLR. The further understanding of how the two limbs interact post ACLR may improve clinical recommendations. The first purpose of this study was to test for changes in tibiofemoral joint (TFJ) and patellofemoral (PFJ) loading parameters as individuals with a history of unilateral ACLR run with a shorter step length. The secondary purpose was to compare PFJ and TFJ loading parameters during running. Variables of interest include peak force, force*time impulse, impulse per km, and average loading rate. Methods: Eighteen individuals ( =22 years) with unilateral ACLR reconstruction 2 to 7 years prior were recruited for the study. Lower extremity gait analysis was conducted using a motion capture system and instrumented treadmill. Participants ran at their preferred speed ( =2.65 m/s) and preferred step length, followed by a 5% and 10% decreased step length condition. Two separate Two-Way analysis of variance were used to test for linear trends across step length conditions (3 factor) and between limb differences (2 factor). Least significant difference tests were used to analyze differences between step length conditions. Results: Linear trends were observed across step length conditions for PFJ, TFJ, and mTFJ peak force (all p [less than] 0.000), PFJ, TFJ, and mTFJ impulse (all p [less than] 0.000), and PFJ, TFJ, and mTFJ impulse per km (all p [less than] 0.012). A 5% and 10% decrease in step length were successful in reducing peak joint force, force*time impulse, and impulse per km by 4 to 12%. Between limb differences were observed. The experimental limb experienced a 7% decreased force*time impulse and impulse per km within the TFJ. Conclusion: Individuals with ACLR who ran with a shorter step length reduced peak force, force*time impulse, and cumulative impulse per km within the PFJ, TFJ, and mTFJ compartment, and these reductions had a linear trend from preferred step length, a 5% decrease, and a 10% decrease. Between limb loading differences were seen within the TFJ. Future longitudinal studies to examine this running modification's effect on knee joint cartilage thickness and health post ACLR appear justified.

Additional Information

Publication

Thesis

Language: English

Date: 2016

Keywords

impulse, step rate, knee biomechanics

Subjects

Wounds and injuries--Prevention; Knee--Diseases; Running--Training; Physical education and training; Osteoarthritis

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