Hip replacement surgery isn't just for seniors anymore: People of all ages, weary of living with constant hip pain, are coming to the University of Maryland Medical System seeking a less invasive option: direct anterior hip replacement.

UMMS hospitals are at the leading edge of advancements in complex hip surgeries, having performed anterior hip surgery for many years with some surgeons at our institutions having switched nearly entirely to the anterior approach.

Hip replacement removes the ball and part of the socket of the natural hip (which is diseased or injured) and replaces them with artificial parts. Direct Anterior Hip Replacement accesses the hip socket from the front of the body, or anterior side. Conventional hip replacement surgery accesses the hip from the back or side. The anterior method avoids cutting through muscle, leading to less muscle injury, pain and scarring.

Over the past decade, the direct anterior approach has gained popularity worldwide as a surgical approach for hip replacement. Hip replacement patients do well regardless of the surgical approach used. However, direct anterior hip replacement reduces the risk of some complications after surgery including hip dislocation and implant malposition.

Many Reasons for Hip Replacement

Patients seeking hip replacements typically cope with one of a handful of medical conditions triggering chronic hip pain, including osteoarthritis; dysplasia, or a misalignment of the hip joint; slipped capital femoral epiphysis, a disorder causing the thigh bone to slip out of place; or a loss of blood supply to the hip from disease or medication use. The best candidates for a direct anterior hip replacement are patients who have not undergone previous hip surgery and whose body mass index (BMI) is under 35, considered the threshold for obesity.

For the anterior surgery, patients are placed on their backs and X-rays are used to more accurately determine the placement of the new hip joint. Surgeons can separate the muscles at the front of the hip without cutting through them, potentially resulting in less muscle damage and a lower risk of hip dislocation (where the hip pops out of the joint) in the days and weeks after surgery.

Since this approach disturbs the tissues in the back (posterior) of the hip less than with other techniques, the hip is usually much more stable afterward. For years prior, surgeons told patients to avoid certain hip movements after surgery to avoid dislocations. Now they tell them not to do anything extreme, but they can resume normal movement immediately with no restrictions on movement.

There is less muscle damage compared to other methods of hip replacement. But the direct anterior approach still involves cutting bones and putting in plastic and metal parts. Patients may think that because the surgery is less invasive — that it is going to be like getting a haircut — but it's still a big surgery. It is, however, less disturbing to the tissues around the hip, which is why patients seem to recover more quickly.

Minimal Risks, Maximum Expertise

The main risks of hip replacement are infection, hip dislocation and leg length inequality after surgery. Direct anterior hip replacement allows surgeons and patients to minimize dislocation by preserving the tissues in the back (posterior) side of the hip joint. Direct anterior hip replacement also allows for more straightforward tests to make sure the patients two legs are as close to being equal as possible, and that the artificial parts are in the correct position.

Anterior hip replacement is associated with one unique side effect: potential numbness on the front of the thigh. A nerve running along the front of the thigh lies near the incision line, and this nerve can get bruised since it's directly adjacent to muscles being moved during the procedure. In the majority of these operations performed by expert surgeons, this numbness is a temporary finding.

Most of the patients who experience it aren't bothered by the numbness, but it's important to understand it can occur and it can persist. For some – between 3 percent and 4 percent of patients – it's permanent. It's just something to be aware of. Most of the patients who have it are still really happy with their new hips.

Patients considering direct anterior hip replacement surgery as a way to relieve chronic hip pain can benefit from the UMMS specialized hip replacement team. This group of physicians  not only trains other doctors in the procedure, but UMMS serves a referral role for complex hip replacement for the states of Pennsylvania, Delaware, Maryland and West Virginia.

Hip replacement, in general, is a life-changing operation for people who have been suffering a long time. Direct anterior hip replacement is simply a slight improvement on a time tested and effective operation to relieve pain. Quite a few of these patients are significantly disabled beforehand, so hip replacement really changes their life and gets them back to doing what they want to do.

Patients can make appointments for any University of Maryland orthopedic service by calling 410-448-6400.