Nov. 14, 2006 (Washington, D.C.) -- Having one leg shorter than the other may increase a person's risk of developing arthritis in a knee or hip, according to a study presented today at the American College of Rheumatology's 2006 annual meeting in Washington, D.C.
People with a leg length difference of as little as 2 centimeters -- four-fifths of an inch -- were more likely to have osteoarthritis in their right hip or their left or right knee. They were also more likely to have more severe arthritis, the study showed.
Often referred to as the "wear-and-tear" form of the disease, osteoarthritis (OA) affects nearly 21 million people in the U.S.
It is characterized by the breakdown of the joints' cartilage, the lining that cushions the ends of bones and allows for easy joint movement.
Breakdown of this cartilage leaves the bones to rub against each other, resulting in pain, stiffness, and loss of movement in the affected joint, according to the Atlanta-based Arthritis Foundation.
"The findings from this study may help us predict who may develop osteoarthritis and who may have symptoms that worsen, or have a potential risk of increased disability," study researcher Joanne M. Jordan, MD, MPH, says in a news release.
"Studies to test whether correction of leg length inequality with orthotics or shoe lifts can prevent the onset of osteoarthritis, or its progression, would be a logical next step," adds Jordan, who is an associate professor of medicine and orthopaedics at the University of North Carolina Thurston Arthritis Research Center in Chapel Hill.
Hip, Knees Affected
Jordan's study looked at 3,161 people enrolled in the Johnston County Osteoarthritis Project.
Of these participants, 1,785 had hip or knee osteoarthritis and 210 of them had legs of different lengths.
Overall, 45% of those with differing leg lengths had knee osteoarthritis, compared with only 29% without a length difference. Increased occurrence for hip osteoarthritis was less dramatic - 32.5% versus 26% for those with and without a leg length difference, respectively.
Leg length discrepancy was equally common among men and women, blacks and whites.
The location of the osteoarthritis did not appear to be driven by which was the longer or shorter limb.
"Recognizing that leg length inequality has a significant association with hip and, particularly, knee osteoarthritis opens the door to more studies on whether leg length variances might cause the development and progression of the disease," Jordan says.
Findings 'Make Sense'
Robert L. Wortmann, MD, professor and chairman of the department of rheumatology at the University of Oklahoma in Tulsa, tells WebMD the new findings make sense and may have implications for prevention of osteoarthritis.
"If you have any injury to a joint, you get osteoarthritis in that joint," he explains. Differing leg lengths also tax the body.
"When your legs are not the same length, the body compensates, which alters the stress across the joints and promotes OA," he says. Basically, the body adjusts itself to compensate for anything that disturbs normal mechanics.
"The treatment for leg length discrepancy is to add a leg lift to the shoes so legs are the same length," he says. "If people are identified early and treated with a shoe lift, they may not develop OA."