Enter the robot. The robotic equipment’s software uses the information generated by the scan to create a personalized preoperative plan for the surgery. With the surgical plan in place, the surgeon uses the robotic arm to insert each end of the artificial hip joint exactly where it should go to maximize anatomical function. The robot moves within a predefined area, minimizing the possibility of surgical deviance from the preprogrammed plan while still allowing the surgeon to make adjustments during the surgery if needed.
“Once the robot comes into the field, it acts as a navigator and co-pilot,” Dr. Meere said. “The surgeon is still in command but needs to expose less tissue and is more confident because the robot knows exactly where the cutting instruments are and where the boundaries of the safe cutting zones lie.”
If the surgeon should drift from the safe zone, the robot issues an alert, comparable to the lane-departure warning in modern cars, and shuts off. In this way, Dr. Meere said, “the robot minimizes the risk of inadvertent damage to bone or surrounding tissues.” It also relieves the surgeon’s stress when operating on complex cases.
A critical factor in successful hip replacement is making sure the leg that is attached to the new hip matches the length of the other leg. Robotic-assisted surgery is reported to be five times more accurate in matching leg length than is conventional surgery. It is also better at inserting the new hip joint at the proper angle.
Before the surgical wound is closed, the surgeon can tell whether the joint is properly aligned and the leg lengths are even, which results in a more stable joint.
Robotic surgery “is where things are going,” Dr. Douglas B. Unis, orthopedic surgeon at Mount Sinai Icahn School of Medicine, told me. “It more accurately reconstructs the patient’s anatomy and results in better mechanical function. Off-the-shelf implants and the carpentry tools used to prepare bone are not good business or clinical models. It’s becoming more economical and practical to design customized implants,” he said, than it is to customize the patient’s bones to fit an existing implant.
Not only have surgical techniques used in hip replacements improved. So has anesthesia, which now usually relies on a combination of treatments like a regional spinal block and peripheral nerve block together with a pain-relief cocktail that is injected directly into the local wound, Dr. Meere said.