Total hip replacements, called total hip athroplasties, are major surgeries with significant recovery time. The are also becoming increasingly common and in demand. As a result, there is a push to improve surgical techniques. As in most surgeries, surgeons are trying to find ways to be less invasive, making as small as possible incisions and moving as little around as possible inside. Some surgeries are now done arthroscopically, which means that very small incisions are made and the surgeon uses long instruments to reach inside and follows progress through a camera that sends the image to a computer screen.
In hip surgery, larger incisions are needed, but surgeons aren't agreeing on how small does an incision have to be before it can be called minimally invasive. Some surgeons feel it is the length of the incision (less than 10 centimeters long) that defines it, but others say that the incision size doesn't matter - what matters is not doing any damage to the muscles near the hip. While both may have a point, the less damage that is done to the muscles and other soft tissues, the faster the likelihood of the patient recovering more quickly.
The authors of this study point out that few studies have been done using the patient's gait (walking) to determine how well the hip replacement has worked, instead of using pain levels, for example. In this study, they wanted to compare the standard surgery that requires them to cut into the glutteal muscle to minimally invasive surgery, shown by how well the patients walk after healing.
To do the study, researchers studied 40 patients who underwent total hip replacement surgery. The patients did not know which surgery they had, the standard one (20 patients) or the minimally invasive one (20 patients). Both groups received the same hip implant, but the methods were different. Treatment after surgery was also the same for both groups. Physiotherapy began on the first day after surgery and the patients were encouraged to begin walking on the first day as well (using crutches). It was recommended to continue using crutches for three weeks after surgery. Weight-bearing was allowed after three weeks if they felt comfortable doing so. Hospital stays for the patients varied from 10 to 13 days.
In order to assess the patients, the researchers evaluated them one day before surgery, 10 days after surgery and again 12 weeks after surgery. The researchers measured and assessed the patients' gaits. While it may have been expected to find that patients who had the more invasive surgery may have more problems with their gait after surgery, that is not what the researchers found. Examining the gain in 3D, they found that both groups of patients had basically the same velocity of their gait, strength, step length, and stride length. Both groups did tilt their pelvis a bit to compensate, but it was pretty well the same in both. One patient in the standard surgery group was seen to have an Trandelenburg gait after 10 days. This gait is seen when the patient's upper body leans forward to the weaker side, but the gait became normal for this patient by the next follow-up visit.