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What Is Varus or Valgus Knee Deformity?

Varus or Valgus Malalignment Can Affect Progression of Knee Osteoarthritis


Updated May 23, 2014

Knee Malalignment Hikes Risk of Knee Osteoarthritis

A knee that is perfectly aligned has its load-bearing axis on a line that runs down the middle of the leg -- through the hip, knee and ankle. When the knee is not perfectly aligned, otherwise known as malaligned, it is known as either varus (bow legged) or valgus alignment (knock-kneed). There is a link between knee malalignment and knee osteoarthritis.

Varus Alignment of the Knee: Bow-Legged Knees

Varus alignment causes the load-bearing axis to shift to the inside, causing more stress and force on the medial (inner) compartment of the knee. If your doctor has said you have varus alignment of the knees (bow-legs), keep in mind that studies show that weight plays a critical factor.

With varus alignment, you are at risk for knee osteoarthritis regardless of your weight -- but if you are overweight or obese your risk is substantially higher than average. Varus alignment increases the risk of knee osteoarthritis 5-fold in obese patients.

Increasing degrees of varus alignment are also associated with progression of knee osteoarthritis as well as the development of knee osteoarthritis -- especially in overweight and obese patients.

Valgus Alignment of the Knee: Knock-Kneed Legs

Valgus alignment shifts the load-bearing axis to the outside -- causing increased stress across the lateral (outer) compartment of the knee. Valgus alignment (knock-kneed) is not considered quite as destructive as varus alignment.

Malignment not only stresses articular cartilage but it also affects menisci, subchondral bone, and ligaments -- all of which may play a role in the progression of knee osteoarthritis.

The Bottom Line Regarding Knee Malalignment

If you are either bow-legged or knock-kneed, you are at higher risk for osteoarthritis, meaning you may develop knee pain and function problems later in life. It's important to keep your weight within a normal range, as obesity can make knee problems worse.

Consult an orthopedic surgeon if you suspect malalignment. Have it evaluated by your doctor and get advice on what you can or should do now to protect your joints. In some cases, joint replacement surgery can correct valgus or varus deformities.


The Role of Knee Alignment in Disease Progression and Functional Decline in Knee Osteoarthritis. JAMA. Sharma L, Song J, Felson D, et al. July 11, 2001.

Varus Alignment Doubles Risk for Knee OA in Overweight Subjects. Musculoskeletal Report. April 25, 2007.

Association Between Valgus and Varus Alignment and the Development and Progression of Radiographic Osteoarthritis of the Knee.Brouwer GM et al. Arthritis and Rheumatism. April 2007.

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