Physicians debate the importance of learning curve for hip resurfacing

Mastery of the procedure may prove difficult for surgeons with limited arthroplasty practices.

Hip resurfacing is becoming a popular choice for the surgical treatment of hip arthritis; however, there are still many controversies surrounding its use, according to two internationally respected hip surgeons.

One controversy — whether or not the learning curve for hip resurfacing is too steep – was the subject of a debate between Jay R. Lieberman, MD, and Andrew Shimmin, MBBS, FAOrthA, at a symposium held during the American Academy of Orthopaedic Surgeons annual meeting.

Four separate facets

Shimmin said four aspects of hip resurfacing add to its difficulty: patient selection; exposure; implant orientation; and postoperative management.

Andrew Shimmin

“The operation is for patients who will likely become increasingly active once rid of their disabling arthritic pain, ie, younger patients with few co-morbidities,” he told Orthopedics Today.

The Australian Registry data from 2008 indicated that the ideal indication was for men younger than 65 years with a primary diagnosis of osteoarthritis. He said those patients had a 2.4% cumulative revision hip resurfacing rate, compared to the total hip replacement rate of 2.8%.

How steep is the curve?

Lieberman said hip resurfacing procedures carry a learning curve that is far too steep for any nonspecializing physician to easily learn. While the procedure may offer distinct advantages if a surgeon performs it well, the price of performing it poorly can be costly.

“My thesis is that hip resurfacing is not appropriate for all arthroplasty patients, and it is probably not the answer for all orthopedic surgeons,” Lieberman said. “The proposed advantages are bone conservation and femoral head retention … but how many cementless femurs have you revised once they have ingrown?”

Shimmin countered that the learning curve itself is acceptable, but a failure to acknowledge its existence is not acceptable.

“I am not going to deny that there is a learning curve,” he said. “But learning curves are present in all surgical procedures.”

A learning curve can be minimized with appropriate training, he added.

Exposure and orientation

Shimmin said the main hurdles in learning hip resurfacing can be easily overcome. He quickly dismissed the second of his four listed hurdles, exposure.

Jay R. Lieberman

“Operative exposure is part of basic surgical training,” he said. “The concept of initial incision which you expand as required is not hard for us to get our heads around, and it is eminently learnable.”

Implant orientation, Shimmin noted, was the most difficult of the four issues. He cited one of his own papers presented at the AAOS meeting 2 years ago that found there was a learning curve to implant orientation.

“But of course, that was with primitive instruments,” he said. “This debate is about today’s practice, and in today’s practice we have improved alignment tools, including navigation,” he said.

Significant practice necessary

Lieberman said the learning curve involved with hip resurfacing demands a remarkable amount of practice.

“There are surgical technique issues — and I think this is what we are going to focus on — that make it difficult if you do not do enough of these procedures,” he said.

He said he asked many surgeons how many surgeries would it take to become competent with this technique and then maintain those skills. The general agreement was 20 to 50 cases, depending on the surgeon’s experience, and to maintain it would take between 20 and 50 cases each year.

“That is a long learning curve,” Lieberman said.

He said that patient supply is a roadblock to performing that many resurfacings, citing registry data indicating that hip resurfacings are performed in about 8% of the cases.

“To perform 25 hip resurfacings in 1 year at that rate, a physician would need to operate on more than 300 hips during that year,” he said.

Postoperative management

The final factor in successfully learning hip resurfacing – postoperative management – poses little if any problem on its own, according to Shimmin.

“We have got to understand and respect, the fact that we have temporarily compromised the femoral neck and head somewhat, so you have to ‘be nice to it’ and suggest some protective weight bearing for 6 weeks,” he said.

Shimmin’s conclusion was that while there is a learning curve to be recognized with hip resurfacing, the basic skills involved in surmounting it are achievable in today’s practice.

The inherent difficulty of a hip resurfacing suggests that a surgeon needs to obtain specialized training and then develop a practice that allows one to do a sufficient number per year to obtain predictability, Lieberman said.

“It is a more difficult procedure than total hip arthroplasty,” he said. “It is a larger incision and more extensive soft tissue dissection. It is not minimally invasive surgery, and I think we would all agree you need some type of specialized training. This is not a procedure for a surgeon with a small arthroplasty practice.

“It is not that this isn’t a successful operation that should not be used at all, but perhaps one surgeon in a group or a hospital should commit themselves to becoming excellent with this procedure,” he added.

For more information:

• Jay R. Lieberman, MD, is a professor and chairman with the Department of Orthopaedic Surgery at the University of Connecticut Health Center. He can be reached at New England Musculoskeletal Institute, UConn Health Center, 263 Farmington Ave., Farmington, CT 06030; e-mail: JLieberman@uchc.edu.
• Andrew Shimmin, MBBS, FAOrthA, is the Director of the Melbourne Orthopaedic Group with the Melbourne Orthopaedic Group and Research Foundation in Victoria, Australia. He can be reached at Melbourne Orthopaedic Group, 33 The Avenue, Windsor, Victoria 3181, Australia; e-mail: ashimmin@optusnet.com.au.

Reference:

• Shimmin A, Lieberman JR. Learning curve to perform hip resurfacing is unacceptable in today’s practice: affirmative, negative. Presented at the AAOS annual meeting in Las Vegas, Nev. Feb. 26, 2009.