Comparison of Minimally Invasive Direct Anterior Versus Posterior Total Hip Arthroplasty Based on Inflammation and Muscle Damage Markers

Background: A number of surgical approaches are utilized in total hip arthroplasty. It has been hypothesized that the anterior approach results in less muscle damage than the posterior approach. We prospectively analyzed biochemical markers of muscle damage and inflammation in patients treated with minimally invasive total hip arthroplasty with an anterior or posterior approach to provide objective evidence of the local soft-tissue injury at the time of arthroplasty. Methods: Twenty-nine patients treated with minimally invasive total hip arthroplasty through a direct anterior approach and twenty-eight patients treated with the same procedure through a posterior approach were prospectively analyzed. Perioperative and radiographic data were collected to ensure cohorts with similar characteristics. Serum creatine kinase (CK), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-1 beta (IL-18), and tumor necrosis factor-alpha (TNF-alpha) levels were measured preoperatively, in the post-anesthesia-care unit (except for the CRP level), and on postoperative days 1 and 2. The Student t test and Fisher exact test were used to make comparisons between the two groups. Independent predictors of elevation in levels of markers of inflammation and muscle damage were determined with use of multivariate logistic regression analysis. Results: The levels of the markers of inflammation were slightly decreased in the direct-anterior-approach group as compared with those in the posterior-approach group. The rise in the CK level in the posterior-approach group was 5.5 times higher than that in the anterior-approach group in the post-anesthesia-care unit (mean difference, 150.3 units/L [95% CI, 70.4 to 230.2]; p < 0.05) and nearly twice as high cumulatively (mean difference, 305.0 units/L [95% CI, -46.7 to 656.8]; p < 0.05). Conclusions: We believe that the anterior total hip arthroplasty approach used in this study caused significantly less muscle damage than did the posterior surgical approach, as indicated by serum CK levels. The clinical importance of the rise in the CK level needs to be delineated by additional clinical studies. The overall physiologic burden, as demonstrated by measurement of inflammation marker levels, appears to be similar between the anterior and posterior approaches. Objective measurement of muscle damage and inflammation markers provides an unbiased way of determining the immediate effects of surgical intervention, in patients treated with total hip arthroplasty.