The Influence of Stride Length, Knee Stiffness, and Leg Strength on the Associations Between Bone Mineral Density, Lean and Fat Mass, and Knee Joint Compressive Forces Among Older Adults With Knee Osteoarthritis

Introduction: It is theorized that those with knee osteoarthritis (OA) exhibit a specific phenotype of high fat mass and bone mineral density (BMD) that is associated with increased knee forces and disease progression. Whether this relationship is mediated by biomechanical factors has not been investigated. Therefore, the purpose of this study was to investigate the associations between leg BMD, fat mass, and lean mass on knee joint compressive forces in older adults with knee OA, and to determine whether these relationships are mediated by stride length, leg strength, and/or knee stiffness.

Methods: Baseline DXA scans, knee extensor strength, and gait data from 75 participants from the Strength Training for Arthritis Trial (START) were analyzed.

Results: Leg BMD (p= 0.006) and fat mass (p<0.001) were positively correlated with knee joint compressive forces. Stride length, average knee stiffness, and leg strength were partial mediators for the relationship between % fat and knee forces. Leg strength was also a partial mediator for the relationship between leg BMD and knee forces,

Conclusion: Elderly obese individuals with knee OA should reduce their % fat and stride length, or alter their leg strength and knee joint stiffness to lower knee joint compressive forces.

Year	Entry
2006	Andriacchi TP, Mündermann A. The role of ambulatory mechanics in the initiation and progression of knee osteoarthritis. Curr Opin Rhuematol. September 2006;18(5):514-518.
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2005	Griffin TM, Guilak F. The role of mechanical loading in the onset and progression of osteoarthritis. Exerc Sport Sci Rev. October 2005;33(4):195-200.
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Year

Entry

2006

Andriacchi TP, Mündermann A. The role of ambulatory mechanics in the initiation and progression of knee osteoarthritis. Curr Opin Rhuematol. September 2006;18(5):514-518.

1997

Burr DB. Muscle strength, bone mass, and age‐related bone loss. J Bone Miner Res. 1997;12(10):1547-1551.

2005

Griffin TM, Guilak F. The role of mechanical loading in the onset and progression of osteoarthritis. Exerc Sport Sci Rev. October 2005;33(4):195-200.

1986

Radin EL, Rose RM. Role of subchondral bone in the initiation and progression of cartilage damage. Clin Orthop Relat Res. December 1986;213:34-40.

1957

Kellgren JH, Lawrence JS. Radiological assessment of osteo-arthrosis. Ann Rheum Dis. December 1957;16(4):494-502.