Bowlegged or Knock Kneed?
What Is Varus or Valgus Knee Deformity?
Knee Malalignment Raises the 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 maligned, it is known as either Varus ( bowlegged) or Valgus alignment (knock-kneed). There is a link between knee malalignment and knee osteoarthritis.
Varus Alignment of the Knee: Bow-Legged Knees
If you have bow-legged knees, and especially if you are overweight, you have an increased risk of knee osteoarthritis and it is more likely to progress once it develops.
Varus alignment causes the load-bearing axis of the leg 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. This may be something you can do something about. If you are overweight and lose weight, you may reduce your risks. In varus malalignment, the medial meniscus is affected.
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 five-fold in obese patients.
Valgus Alignment of the Knee: Knock-Kneed Legs
Being knock-kneed is the opposite problem but may still result in progression of knee osteoarthritis.
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. In valgus malalignment, the lateral meniscus is affected.
It's important to note that in addition to damaging the cartilage and causing joint space narrowing, knee malalignment is also believed to affect the menisci—and meniscal damage is believed to be a risk factor on its own for developing osteoarthritis.
The Bottom Line Regarding Knee Malalignment
Malalignment 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.
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. It is the factor that you can have some control over without surgery.
You may look in the mirror and decide you have bowlegs or knock-knees.
Schedule an appointment with Dr. Hayter for a consult, if you suspect malalignment. In some cases, joint resurfacing surgery can correct valgus or varus deformities. You and Dr. Hayter can discuss the options that will be best to help decrease your pain and increase your mobility.