More and more surgeons are opting to perform minimally invasive surgery (MIS) for total hip replacements (THR). MIS is not simply defined by the size of the incision; rather it attempts to reduced damage to all of the soft tissues. Patients’ demand is the primary driver of MIS implementation. MIS is not a silver bullet, though, and drawbacks include longer surgical procedures, more difficulty performing the procedure as a result of reduced visibility and a longer surgical learning curve, as well as increasing the chance of poor component positioning or having a surgical complication.

There are several MIS approaches to the hip, two include the direct anterior (DA) approach and the direct superior (DS) approach. Heretofore, there is no consensus on which approach is better for MIS-THR. To determine which method of MIS-THA inflicted the least amount of damage to the soft tissue, Dr. Amanatullah and three other colleagues performed a matched-pairs test using eight cadaveric specimens procured from the Medical Education Research Institute in Nevada. For each specimen, one hip was be replaced using the DA approach and the other was replaced using the DS approach.

After analyzing the amount of damage sustained to the muscles and tendons that were cut, torn, or otherwise damaged during each approach, the researchers determined that the DS approach cause less inadvertent muscle damage than the DA approach. The DA approach caused markedly more damage to the gluteus minimus muscle and tendon. Additionally, the DA approach damaged the tensor fascia lata and rectus femoris muscles while the DS approach did not.

To read the full methodology and see all the data, read Dr. Amanatullah’s study in The Bone and Joint Journal.