Yes. If both hips are replaced, it is possible to increase the leg length on one side and increase it by the same amount on the other side. But, any gain in height is about an inch or less. The limiting factor includes the muscles, tendons, and nerves, which only have so much stretch before there is injury or damage.
It is possible to replace both hips at the same time, if the patient is healthy enough for such surgery. Recovery from two hip replacements does not differ much from having one hip replaced, at least with our newer, less-invasive surgical methods.
This is an important topic, and should be understood before you embark on any hip replacement, no matter where you have the hip replacement done.
Hip resurfacing is an operation that is similar to replacement. During resurfacing, the arthritic ball is capped with metal, and an artificial socket is placed in the pelvis. Any bone removed is replaced with an equivalent thickness of metal in hip resurfacing, so there is no noticeable gain or loss in leg length during hip resurfacing.
In contrast to hip resurfacing, during hip replacement the arthritic ball is removed and replaced with a new ball. Since the artificial ball comes in different neck lengths, the surgeon is able to adjust muscle tension, leg length, and ball-socket stability during the hip replacement. These adjustments reflect complex decision-making and trade-offs during surgery. Rarely, because of anatomic constraints or other patient-specific reasons, slight leg lengthening may occur. If this is totally unacceptable, you should not consider hip replacement surgery.
In the overwhelming majority of cases, there is no change in leg length after hip replacement. In most cases where the patient feels a change in leg lengths, that perception will disappear over several months as the muscle and tissues stretch.
Yes. An example would be a patient with a leg that was shortened from injuries after a motor vehicle accident, who now needs a new hip. In such cases, it is possible to restore the original leg length during surgery. The decision-making is complex, requires professional judgment, and is specific to each situation.
Likewise, if the patient has too long a leg before surgery, it is possible to shorten it during hip replacement, using specific surgical techniques that keep muscle tension within safe limits. Again, the exact steps taken and the decision-making are specific to each patient.
In most cases, with exercise, stretching, and healing over 6 to 12 months, the perception of a leg length difference will disappear on its own. During this time, to avoid a limp and facilitate walking, a shoe-lift built into the shoe can help.
The reason for waiting is that the majority of leg-length discrepancy after hip replacement is not a true difference in skeletal lengths. Rather, the discrepancy is from pelvic tilt, tight muscles, altered biomechanics, and even spinal arthritis that can lead to a curvature in the back. With muscles stretching, exercises, and time, such discrepancy will likely resolve in a few months.
If leg length discrepancy is permanent, additional surgery may be an option. During such surgery, the femoral stem component is removed, and the bone at the top of the femur is removed to equalize the leg lengths. Then, a new femoral stem is implanted.
While this sounds easy, additional steps must be taken to avoid improper muscle tensioning and to reduce the risk of creating hip instability and a limp. Recovery from this type of surgery is about 6 to 12 weeks.
Special X-ray studies can help determine if the perceived difference in leg lengths is really in the bone or arising from some other source, such as a tilted pelvis, a curvature in the back, or tight muscles. These X-rays, called scanograms, involve imaging the entire length of both legs with a measuring ruler that leaves no doubt about the actual length of each leg, from the top of the pelvis to the ankle.