As a former standout college and professional football player, Christopher Anthony, MD, appreciates the importance of moving fluidly and efficiently in both life and sport. As the Director of the Penn Medicine Hip Preservation Center, he knows all too well how critical the hips are to enabling, and impeding, such movement.
Chris Anthony, MD
Hip preservation refers to the medical and surgical interventions that can be employed to help active adults who are hindered by a hip disorder alleviate their pain, restore their range of movement, and prevent future joint disease. These interventions can be used for adults of all ages.
The Penn Hip Preservation Center distinguishes itself as one of the few comprehensive centers in the region that provides the full gamut of treatment options.
The field is relatively new. Many of the procedures offered by the center were developed as recently as 10 to 15 years ago, according to Dr. Anthony — and are quickly evolving.
Case in point: Hip cartilage transplantation, or an osteochondral autograft or allograft transplantation, a surgical treatment that's performed at the center, on average, once a month, has been around for only a decade. It provides an effective solution to a fairly common condition where previously there was none.
What Is Hip Cartilage Transplantation?
"When you have a cartilage defect on the femoral head or in the acetabulum, we can replace it with either your own cartilage or allograft cartilage in an effort to improve symptoms and prolong the life of the hip," Dr. Anthony explains.
Those symptoms can include severe pain and an inability to bear weight on the hip. Left untreated, many chronic hip conditions can lead to osteoarthritis and eventual hip replacement, a procedure Dr. Anthony also performs.
Currently, surgeons at the Penn Hip Preservation Center are able to repair cartilage defects that range in size from 10 millimeters in diameter to three centimeters.
For an autograft transplant, the surgeon will remove a small, cylindrical segment of healthy cartilage and bone, typically from a non-weight-bearing area of the patient's hip, reshape it and then replace the defect with the graft. This approach is generally reserved for small defects because of the limited availability of healthy cartilage from the same joint.
An allograft transplant is collected from a cadaver through a certified tissue bank. Before placement, the cartilage graft is sized to match the patient's anatomy, which improves the likelihood of restoring the hip's natural geometry.
A New Solution Where There Was None
Prior to the advent of the hip cartilage transplant, a patient presenting with even a small hip cartilage defect was likely to be presented with two treatment options: hip replacement or microfracture, a surgical procedure that entails drilling holes in the damaged cartilage to mechanically stimulate the underlying bone and marrow. This causes the marrow to produce fibrocartilage, a cartilage substitute that acts as a new cushion for the hip, restoring joint structure and function.
But, for all intents and purposes, Dr. Anthony says, "we didn't have a great solution before we had this technology."
While cartilage transplantation is commonly used to treat cartilage defects in the knee, hip cartilage transplantation is performed at only a small number of institutions across the country. Dr. Anthony says this is largely due to the unique expertise that's required of the surgeon.
"In order to gain the necessary access to replace the cartilage defect, you have to fully expose the femoral head and acetabulum through a surgical hip dislocation," he explains. "But you also need to preserve the blood supply to the hip, which significantly adds to the procedure's degree of difficulty."
The transplantation is similar in many aspects to a periacetabular osteotomy, or PAO, an open surgery that's also performed at the Penn Hip Preservation Center to reorient the hip socket. Here, the goal is to improve coverage of the femoral head by the socket, particularly for dysplastic hips.
Hip cartilage transplantation is designed to treat patients who have been diagnosed with a focal cartilage defect no larger than three centimeters in diameter and who have sound cartilage, otherwise, throughout the remainder of the joint. Those who fit this profile are typically under 50 and physically active.
There are outliers, of course, but Dr. Anthony says the vast majority of patients who undergo transplantation at the center fit this profile.
Dr. Anthony also believes this particular demographic can best weather the recovery from the surgery, which can be rigorous. Someone with an arthritic hip where a substantial amount of the cartilage covering the joint surface has eroded is not an appropriate candidate for a hip cartilage transplant, largely because of the limitations of the procedure.
"We don't yet have the ability to replace the entire joint with cartilage," he shares.
Patients are generally relegated to crutches for the first four weeks following the procedure. At about three months post-surgery, patients are encouraged to gradually resume running, assuming their healing has met certain benchmarks. By six months post-surgery, patients are typically back to exercising and competing at their normal baseline.
Which, considering the pain they were likely in previously, could feel like a small price for a future they hadn't dared let themselves imagine.