Changes in serum creatine kinase and C-reactive protein after posterior and direct anterior approaches in total hip arthroplasty

Purpose: Some studies reported that measuring serum creatine kinase (CK) level is an objective method with which to determine the relative invasiveness of surgery. The purpose of this study was to evaluate the change in postoperative serum CK levels as a measure of whether the direct anterior approach (DAA) is less invasive than the posterior approach (PA) regarding postoperative rehabilitation. Materials and methods: We prospectively recruited 71 women who were undergoing total hip arthroplasty, 47 were treated by the PA and 24 by the DAA. Serum CK and C-reactive protein (CRP) levels were measured preoperatively and 3 hours and 1, 4, 7, 10, and 14 days after the operation. Results: The serum CK levels were significantly higher in the DAA group than in the PA group on postoperative days 1, 4, 7, 10, and 14. On postoperative day 4 and 7, the percentage of patients whose serum CK levels were above the normal range was 46.8% and 8.5% in the PA group and 95.2% and 45.5% in the DAA group. Conclusions: CK levels were significantly higher in the 2 weeks after THA by a DAA than after the same procedure by a PA indicating that DAA causes prolonged muscle damage. Although the DAA is considered to be a muscle-sparing approach this may not be the case and DAA may not actually be a minimally-invasive approach.