Coxa vara is a type of hip deformity in which the end of the femur meets the hip joint at an unusual angle. The result is an upper leg that protrudes outward slightly, causing it to be shorter than the other leg and often causing the sufferer to have an awkward gait or limp. Coxa vara can be a congenital condition, meaning that the defect arose during pregnancy, a developmental disorder of early childhood, or an acquired injury resulting from trauma. When the deformity causes major mobility problems, surgery is needed to correct the angle.
The hip is a ball-and-socket joint, with the end of the femur representing the ball. Just underneath the ball is the femoral neck, a thinner portion of bone that is normally angled about 135 degrees to allow the ball to fit in the joint properly. Coxa vara occurs when the angle is less than 120 degrees. Instead of a leg that is more or less in line with the hip, an affected femur pokes out from the top and angles inward toward the bottom.
The causes of congenital coxa vara are not well understood, though problems may arise due to fetal injury, metabolism problems, or malnutrition in the mother. If the condition is mild, it may not be recognized for several months or even years until the infant exhibits difficulties crawling, standing, and walking. Developmental coxa vara, which usually worsens from early childhood through adolescence, may be caused by a bone disorder, poor nutrition, or unknown reasons. A person may also develop coxa vara later in life due to a car accident, sports injury, fall, or another type of major trauma.
Most cases of coxa vara are unilateral, meaning that only one leg is affected. The condition itself is usually painless, though people may suffer aches and discomfort after activities due to excess strain being placed on the shorter leg. A severe deformity can significantly limit a person's ability to walk and run. Constantly limping can also cause emotional distress and self-consciousness.
Coxa vara can usually be diagnosed with simple X-rays. A radiologist can measure the angle of the femoral neck to determine whether or not it falls into the normal range. If the problem is mild and the patient is not in pain, treatment is usually discouraged. Major cases often require surgery to reshape the femoral neck with metal pins and screws. Following surgery, a patient can expect to spend several months in recovery and possibly years in physical therapy to rebuild strength in the leg.