Which Approach Is Better for Total Hip Arthroplasty?

Study findings suggest similar recovery patterns for posterior, direct anterior approaches

Peter Pollack

Posterior approach (PA) and direct anterior approach (DAA) total hip arthroplasty (THA) have similar patterns of recovery, although range of motion and strength may need to be addressed after PA THA, according to data presented yesterday. The authors of Scientific Presentation 043, “Similar Improvement in Gait Parameters with Direct Anterior and Posterior Approach Total Hip Arthroplasty,” explain that gait velocity improved significantly in the PA group to reach the same level as that of the DAA group at 6- and 12-month follow-up.

The research team prospectively enrolled 22 patients with unilateral primary hip osteoarthritis who underwent THA at a single institution. Each cohort (PA and DAA) had 11 patients, and both cohorts had similar age, sex, and body mass index (BMI) distribution. Patients with a BMI of more than 30, history of previous surgery to the hip, polyarthritis, history of knee replacement in the same limb, an inability to walk without a cane or a walker, neurologic disorder known to affect gait and those with Crowe type 3 or 4 dysplasia were excluded from participation in the study. A single surgeon performed all procedures using implants with a similar design: a noncemented acetabular component, a tapered wedge femoral component, and ceramic-on-polyethylene bearing surfaces.

The researchers analyzed gaits using a combination of reflective markers placed on the lower extremity and six infrared tracking cameras. They recorded ground reaction forces with a multicomponent force plate and used repeated-measures analysis of variance to compare changes in gait parameters over time. They used the Harris Hip Score to quantify pain and function.

“Preoperatively, the gait velocity was higher in the DAA group as compared to the PA group,” the authors write. “In the PA group, gait velocity significantly improved over time at 6 months and 1 year, but not in the DAA group. But the values were similar to that of the DAA group at 6 months and 1 year, corresponding to the high preoperative values in the DAA group.”

In the PA group, mean Harris Hip scores improved from preoperative 53.32 to 87.47 at 6 months and 91.34 at 1 year. In the DAA group, mean Harris Hip scores improved from a preoperative 54.84 to 82.03 at 6 months and 92.33 at 1 year.

Rehab may improve outcomes
According to the authors, one note of importance in their study is the clinical effect of the release of external rotators during PA THA. During a typical gait cycle, the hip is in internal rotation during the loading response and the mid and terminal parts of the stance phase. The hip goes into external rotation during the pre-swing part of the stance phase. After surgery, hip range of motion in the transverse plane diminished in patients in the PA group; this deficit persisted up to 1 year postoperatively. The authors suggest that a specific rehabilitation program focused on improving the external rotation range of motion and strength may be of value after PA THA.

The authors note that their study has several weaknesses:

“There was no healthy control group,” they explain, “hence it is not possible to comment if the gait parameters in the operative group were restored to normal levels. However, the aim of the study was to just compare difference in gait patterns after DAA and PA THA. Also, this was a nonrandomized study design with differences in preoperative walking velocities between the two groups. There was a significant improvement in the walking velocity in the PA group, but was still lower than the DAA group at 6 months and 1 year.”

The study authors were Karl F. Orishimo, MS; Ian J. Kremenic, MD; Parthiv A. Rathod, MD; Ajit J. Deshmukh, MD; and Jose A. Rodriguez, MD.

Disclosures—Mr. Orishimo: no information available; Drs. Kremenic, Rathod, and Deshmukh: no conflicts; Dr. Rodriguez: Smith & Nephew, Wright Medical Technology, DePuy, Exactech, Arthrex, Journal of Arthroplasty, Clinical Orthopaedics and Related Research, HSS Journal, and American Association of Hip and Knee Surgeons

2013 Annual Meeting News
Tuesday through Friday, February 19 – 23, 2013.
http://www.aaos.org/news/acadnews/2013/AAOS8_3_20.asp