Deformities (genu varum / genu valgum)
Understanding this condition
Normally, viewed from the front, the leg is almost straight. When the axis deviates outwards (bow-legged, like brackets), this is called genu varum. When it deviates inwards (knock-kneed, like an X), this is called genu valgum.
These deformities can be constitutional (present since childhood), or develop gradually through asymmetric wear of the knee cartilage. They often reinforce each other: a deviated axis wears one compartment more, and the wear accentuates the deviation.
Symptoms
The deformity is visible to the naked eye, sometimes well before the onset of pain. When pain does appear, it is located in the overloaded compartment: medial for genu varum, lateral for genu valgum.
Functional impairment (limp, reduced walking distance, stiffness) progressively accompanies the worsening.
How can it progress?
An uncorrected deformity sustains and accelerates asymmetric cartilage wear. In the long term, progression is towards unicompartmental then global knee osteoarthritis.
The earlier the axis is corrected, the better the joint is preserved, and the more a joint replacement can be delayed or even avoided.
Treatment options
For moderate, minimally symptomatic deformities: monitoring, orthopaedic insoles, physiotherapy, weight loss if necessary.
For symptomatic deformities in younger patients with relatively preserved cartilage, a realignment osteotomy allows straightening of the axis by cutting and redirecting the bone. This relieves and preserves the knee for many years. When osteoarthritis is too advanced, a knee replacement is the solution. A consultation and imaging workup determine the appropriate indication.