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Minimally invasive hip surgery debated
Two hip surgeons squared off at CCJR; both agreed that special training is needed.
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ORLANDO, U.S.A. — A recent debate between two hip surgeons on the pros and cons of minimally invasive hip replacement surgery showed that both factions agree on some issues.
Despite the differences of opinion that remained, they agreed that there is a steep learning curve and that special instrumentation and skills are needed to perform the procedure safely and effectively.
In one of the Orthopaedic Crossfire debates at the 19th Annual Current Concepts in Joint Replacement Winter 2002 Meeting, here, Thomas S. Thornhill, MD, of Boston, presented the problems with the procedure; Lawrence D. Dorr, MD, of Los Angeles, argued that the procedure has merit.
Minimally invasive not defined
Thornhill said there is no definition of minimally invasive hip surgery. “Is it one small incision or two incisions?” he asked. He also questioned whether one approach — posterolateral or anterolateral — and fluoroscopic guidance are critical to the outcome. “The key issue is the extent of soft tissue dissection,” he said.
Even if the procedure is defined, Thornhill questioned whether there is a reason for doing minimally invasive hip replacements. They should not be done for cosmetic purposes but rather to shorten the hospital stay and accelerate the rehabilitation process, he said.
“If that’s true, the size of the incision is a minor factor,” said Thornhill, chairman of the department of orthopaedic surgery at Boston’s Brigham and Women’s Hospital. “[Mini-incision hip surgery is] a program of teaching and preoperative education, change of anesthesia protocols … for same-day discharge. It’s a matter of limiting the dissection regardless of the approach,” he said.
Implant positioning, soft tissue balancing and a robust postoperative home care program are critical to the success of the surgery. Thornhill said he questions whether proper orientation of components is possible and whether all debris could effectively be cleared from the area to prevent infection.
Dorr said he has performed nearly 250 of the procedures and is in favor of doing them regularly based on outcomes after operating on 105 consecutive hips in 90 patients. He defined the procedure as an incision <10 cm long.
Few complications
Patients (aged 37 to 85; average body mass index, 19 to 37) in his series had an average incision size of 8.2 cm; 16 patients required an incision >10 cm.
“We can do the operation in one hour, which is about 10 minutes slower than with a long incision,” Dorr said. There were two complications: one case of sciatic nerve palsy at one month postop and one infection. Dorr was concerned about the infection, which occurred in an earlier case. “I don’t think that one [infection] is a small number. I’ve never had a 1% infection rate,” he said.
Infection and other problems may be avoided by using special curved tools that do not impinge on skin edges but instead protect the skin. “Tension on the skin decreases vascularity to it and it increases the infection rate. … It is important that your instrumentation allows you to do the operation without tension on the tissues.”
Positional changes may help make the procedure safer. For example, in those cases where the neck of the prosthesis impinges on the implant, the patient’s leg should not be internally rotated over the side of the table. This over-stretches the sciatic nerve and may result in a nerve palsy, Dorr said.
Fewer narcotics used
Fewer narcotics were used and hospital stays were shorter with the minimally invasive procedure. “Twenty percent of patients can leave within 48 hours. [They] have good muscle function and gait is 80% to 90% of normal at three months. This operation can be done very quickly and efficiently,” Dorr said. Although it can be done predictably and reproducibly, it needs to be done as well as with a large incision. If this cannot be achieved, he said he is in favor of not using a small incision.
Session moderator Cecil H. Rorabeck, MD, FRCS, of London, Canada, said that not only should the indications for the procedure be defined, “but perhaps, most importantly, the limitations.”
For your information:
- Dorr LD. The mini-incision hip: building a ship in a bottle. In the affirmative. #14. Presented at the 19th Annual Current Concepts in Joint Replacement Winter 2002 meeting. Dec. 11-14, 2002. Orlando.
- Thornhill TS. The mini-incision hip: building a ship in a bottle. In opposition. #13. Presented at the 19th Annual Current Concepts in Joint Replacement Winter 2002 meeting. Dec. 11-14, 2002. Orlando.