Paradigm shift in osteonecrosis treatment moves THR, core decompression into favor

Free fibular grafts and femoral osteotomies that have increased morbidity are no longer justified.

In just the last couple of years clinicians have gained many new insights into managing patients with hip osteonecrosis based on improved results treating this disease.

Investigators now believe, for example, that total hip replacement (THR) is indicated in many young patients with osteonecrosis. Before, they disapproved of it in that population because they thought if it was done too early, multiple revisions might be needed.

Today, good results with modern bearing surfaces have helped changed that attitude, said David S. Hungerford, MD.

Core decompression works well, too. “The literature review shows success rates in the 60% to 70% range compared to nonoperative treatment,” he said in a presentation at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting.

Results that Hungerford and colleagues presented in 1994 showed an 80% success rate with core decompression in stage 1 and 2, precollapse disease. “Core decompression remains the mainstay for those patients for whom it is applicable, which will be probably not more than 20% or 25% of all patients with osteonecrosis.”

Paradigm shift

Practical outcomes information like this has improved prospects for the tens of thousands of people diagnosed with this condition each year. “I believe that there’s really a paradigm shift in the treatment of osteonecrosis,” said Hungerford, who is at Good Samaritan Hospital in Baltimore. He is clinical director of the Center for Osteonecrosis Research and Education.

As a result of the new paradigm, a few once-popular osteonecrosis treatments are now out of vogue, such as femoral osteotomies. They were not only associated with increased morbidity, but also negatively affected the proximal femur.

Preserving the femoral head has also fallen out of favor, Hungerford said.

Except in rare cases, performing an even more complicated procedure, like implanting a free fibular graft, has become unnecessary mainly because it is so extensive. “It has a significant morbidity, a significant complication rate, and I don’t believe you can justify it for most patients,” Hungerford said.

But, when treating hip osteonecrosis today, physicians still need to assess the pros and cons of each procedure being considered. That includes evaluating its current success rate, morbidity, potential for complications, and how it might impact doing a THR at some later date. “Not all treatments have equal risk,” he noted.

In each case, the surgeon must consider two main factors: Whether subchondral collapse of the femoral head has already occurred, and lesion size calculated by determining the Kerboull angle.

The best prognosis exists for hips in stage 1 and 2, with precollapse disease, and with an intact femoral head, and with smaller lesions, since they may not progress, Hungerford said.

“Most patients will present with advanced disease. Therefore, most patients are going to need an arthroplasty,” including those in their 30s.

For more information:
Hungerford DS. Osteonecrosis: Problem solved? #87. Presented at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting. May 21-24, 2006. Las Vegas.