Surgical Approaches to Total Hip Replacement
The hip joint can be approached from the front of the hip (anterior approach), from the back (posterior approach), from the side (trans-trochanteric approach), from midway between front and side (antero-lateral approach), or through a two incision approach (one anterior, and one posterior).
With the side-approach the trochanter bone is cut, and later re-attached with steel wires. This was the standard for many years, but is now only occasionally used for re-operations.
THE POSTERIOR APPROACH is the one used by most surgeons. Small, unimportant tendons (short rotators) are detached to get to the hip joint, and re-attached later in the operation. Normal walking returns much sooner than with the antero-lateral approach, sometimes in less than six weeks.
THE MINI-INCISION HIP REPLACEMENT is an important recent development. It is used with the posterior approach. In the past the skin incision was ten or more inches long. With special new instruments, this approach is now possible through an incision as small as three inches in thin patients. In obese patients, the incision is less than half what it would otherwise have been.
A smaller incision means less blood-loss. There is also less trauma to the muscles and ligaments around the hip, so much less pain, and an even quicker return to normal walking. Few orthopedic surgeons have learned the posterior mini-incision. Fewer still can do a perfect hip replacement, with accurate leg length, through such a small incision.
THE ANTERO-LATERAL APPROACH, is the second most commonly used. The chance of hip dislocation is thought to be less with this approach. However, there is a trade-off. About one third of the most important hip muscle (gluteus medius) is detached from the bone, and later re-attached. This weakens it, leaving most patients with a limp, sometimes for up to a year.
IN THE ANTERIOR APPROACH the whole operation is done through a single incision in the groin. The muscles are not cut, but are spread apart. The ligaments that hold the hip together still have to be cut. The procedure is done under x-rays. The operation is risky, even in the best hands. It is very difficult to line up the femur bone through this incision, and see it clearly. There is much room for error in the placement and sizing of the femoral component, as well as in getting the leg length right.
THE TWO-INCISION APPROACH is a very recent development. Two 3-inch incisions are made: one in the groin, as in the anterior approach, and one over the back of the hip. Muscles are not cut, but are spread apart, and are disturbed less than with any other approach. Normal walking returns sooner with this approach than with any other, sometimes in as little as two weeks. The operation is difficult, and very few surgeons have been trained to do it.