Mini-incision total hip arthroplasty: a quantitative assessment of laboratory data and clinical outcomes.

In this study, we used laboratory data and clinical outcomes to evaluate the degree of approach-related trauma in mini-incision arthroplasty. In 94 patients (8 male and 86 female), a total of 100 osteoarthritic joints were replaced using total hip arthroplasty (THA). The level of serum C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were measured 1 week postoperatively in both the standard group and a mini-incision group. The serum CRP level (mean +/- standard deviation) was 3.3 +/- 2.6 mg/dl in the standard incision group compared to 1.8 +/- 1.2 in the mini-incision group. The ESR level was 66 +/- 22 mm/h in the standard incision group and 52 +/- 20 mm/h in the mini-incision group. The ratio of the level of creatine phosphokinase (CPK) measured postoperatively/preoperatively was 4.7 on the first postoperative day in the standard incision group and 3.6 in the mini-incision group. On the basis of the CRP and ESR levels, the mini-incision THA was considered to be less invasive. However, there was no significant difference in the day 1 CPK ratios between the two groups, suggesting that the degree of muscle trauma was similar.