Abstract
My goal for every patient undergoing THA is to achieve a perfect result. At the very least this includes no pain at any time, normal range of motion, normal functionality and a minimal chance of a second operation. Both the Posterolateral Approach (PLA) and the Direct Anterior Approach (DAA) have the capability of achieving these important goals.
However, when you dive deeper into the goal of a “perfect” THA, some differences between the approaches become apparent. These include less muscle damage, faster recovery, and no restrictions at any time with the DAA as opposed to the PLA. Also there is some evidence of better wound healing (Poehling) and less chance of thromboembolic disease with the DAA (Stryker).
The PLA violates all posterior structures of the hip joint, and specifically also goes through the gluteus maximus muscle. Done properly, the DAA spares all the gluteal muscles, and all of the posterior muscles about the hip. Bergin, who demonstrated lower levels of creatine kinase using the DAA vs PLA, has provided evidence of lower muscle damage.
Faster recovery patterns have been well documented after DAA (Christen, Taunton). Part of this may be related to not needing hip precautions after DAA, while PLA patients are restricted in certain activities and positions in the postoperative period, because of the violation of the posterior capsule. Not having any restrictions enhances patient confidence, and patients tend to do more activities sooner with less reluctance and a subsequent faster recovery.
It is my belief that DAA problems (outside the learning curve) are related to the dependence upon special tables and fluoroscopy, as opposed to proper exposure, to perform a DAA. If you don't test hip stability in the OR, you will miss subtle impingement that can lead to postoperative dislocation. If you depend upon fluoroscopy to guide acetabular reaming (without proper exposure), you run the risk of over-reaming or asymmetric reaming with dire consequences. If you don't measure leg length directly, but rely on fluoroscopic measurements, you run the risk of inadvertent leg lengthening.
