Form and Function: Leg alignment
by S. Robert Rozbruch, MD
Co-Chief of the Limb Lengthening and Deformity Correction Unit
Hospital for Special Surgery
Assistant Professor of Orthopaedic Surgery
Weill Medical College of Cornell University

It is well known that form and function go together in the human body. For example, an athletic body not only
works well but is also attractive. Healthy and fit individuals have bodies that both feel good, work well, and look good.

This concept also applies to alignment of the leg. A normally aligned leg has pressure evenly distributed across the knee. A straight weight-bearing line from the hip to the ankle typically passes through the center of the knee establishing this balance (figure 1).

People with a bowlegged alignment (genu varum) experience more pressure on the inside part of their knees since their weightbearing line passes through the inside part of their knees (figure 2).

In contrast, individuals with a knock knee alignment (genu valgum) experience greater pressure on the outside part of their knees resulting from their weightbearing line passing through the outside part of their knees.

Moderate to severe variations from the normal alignment are both cosmetically noticeable and functionally compromising. It is not uncommon for an adult with bowlegs to develop pain on the inside of their knee. Degeneration of the cartilage in that specific area can be observed and documented through arthroscopy (a telescope placed into the knee joint) and MRI scanning of the knee.

Numerous scientific studies have, in fact, documented the relationship between mal-alignment and progression of arthritis on one side of the joint related to the pressure overload. And, people with these alignment differences are often unhappy with the appearance as well. So, whether it has been for cosmetic reasons or to stop pain and progression of arthritis or both, we have treated many patients with mal-alignment successfully.

We perform a minimally invasive surgical procedure to correct the alignment and straighten the leg. Through a one half inch skin incision, the bone is partially cut and the leg is straightened (figure 3) with the help of an external fixator. The procedure takes about one hour and involves a one-night stay in the hospital. The external fixator is a scaffold on the outside of the leg that is applied through a few one-quarter inch stab wounds. This is used to help straighten the leg and to support the healing bone. This is a very functional treatment in which patients are encouraged to walk, put weight on their leg during the treatment. No casts are necessary, and exercise of the knee and ankle are encouraged during the treatment.

We have noticed a dramatic improvement in pain that was localized to one side of the knee as well as improved function and appearance. With the legs are straightened, patients will often gain one-half inch in height as a bonus.

So, whether it is for form or function, correction of mal-alignment is a minimally invasive procedure that makes people both feel and look better. (see figures 4 & 5 below)

Patient examples:
I. Nicole had a bowleg (varus) deformity of her right knee with pain on the inside of the knee. After the realignment, her pain was improved.

fig. 4a, before	fig. 4b, during	fig. 4c, after

II. Michael had bowlegs (genu varum) since childhood. He developed pain on the inside part of both of his knees that prevented him from keeping active. The realignment improved the appearance and stopped the pain.

figure 5: (click photos to enlarge)

fig. 5a, before	fig. 5b, during	fig. 5c, during	fig. 5d, after