At a medical meeting in Miami, James Wenz floored fellow orthopedic surgeons when he showed them a videotape of the hip replacement procedure he’s been using. Most of them, he says, "were pretty amazed." What staggered the orthopedists was the small incision Wenz makes. Small in his case means a 7 centimeter cut—about 3 inches—compared with the foot-long slit used in conventional hip replacement surgery. With such a minimal incision, Wenz is able to cut into less tissue and muscle than in the typical surgery, which for the patient means a less-painful, speedier recovery. "With this surgery, the majority of people can put their full weight on their hip the next day," Wenz reports. In the typical approach, the pain and the time it takes for muscle to repair keep patients on walkers or crutches for up to 12 weeks. 
| Making only a 3-inch incision, orthopedic surgeon James Wenz, above right, is able to expose the top of the thigh bone (top insert), which he replaces with a titanium implant (bottom inset). The mini-incision means faster recovery for the patient. |
The main criteria for pulling off this novel hip replacement is experience. The surgeon needs to visualize through touch anatomy that’s hidden away. Wenz, who’s done more than 300 of the procedures, is able to figure out precisely where to operate by studying preoperative X-rays and by very carefully palpating the terrain of the hip beneath the skin to form an image of its shape and location. His incision needs to provide access to both the top of the femur or thigh bone, in which he will insert the stem and head of the implant, and the hip socket, where he will attach a plastic-lined metal cup that houses the head. A mistake of just centimeters won’t allow enough room to insert the implant. "If you don’t get the location absolutely perfect, you can’t do the procedure," Wenz makes clear. Some orthopedic surgeons have been reluctant to do the mini-incision hip replacements, because in early operations there appeared to be a greater likelihood that the implant would fall out of the hip socket. Wenz has avoided that problem by preserving the capsule of tissue that extends from the socket to cover the head or ball of the implant stem. In the conventional approach, this tissue is removed. "We cut it open and fold it out, and then at the end of the procedure fold it back in and suture it down," Wenz explains. The process reduces risk of dislocation. The two categories of patients for whom the procedure doesn’t work are those with unusual hip anatomy and people who’ve already had hip-replacement surgery. But Wenz now uses the technique on almost all of his patients and believes that as instruments evolve and surgeons become more confident with the approach, it will become the standard way to do total hip replacement. — Gary Logan
Hopkins Medical News, Spring 2001 |
