Less inflammatory response in the direct anterior than in the direct lateral approach in patients with femoral neck fractures receiving a total hip arthroplasty: exploratory results from a randomized controlled trial.

Background and purpose: It is still debatable which is the least invasive approach to the hip joint in arthroplasty for a femoral neck fracture (FNF). We compared the traditional direct lateral approach (DLA) with the direct anterior approach (DAA) regarding creatine kinase (CK), C-reactive protein (CRP), and hemoglobin (Hb).

Methods: In a randomized controlled trial, 130 elderly patients with dislocated FNFs treated with total hip arthroplasty (THA) were included. CK, CRP, and Hb were measured preoperatively and on postoperative days 1 to 4 and were compared between the DAA and DLA groups using repeated measures mixed-effect models.

Results: The CK level was significantly higher on the 1st postoperative day in the DLA group, 597 U/L (95% confidence interval [CI] 529-666) vs 461 U/L (CI 389-532), estimated mean difference (MD) 136 U/L (CI 38-235). The CRP levels were significantly higher on postoperative days 3 and 4 in the DLA group, 207 mg/L (CI 189-226) vs 161 mg/L (CI 143-180), estimated MD 46 mg/L (CI 19-72) and 162 mg/L (CI 144-181) vs 121 (CI 102-140), estimated MD 41 mg/L (CI 15-68). Blood loss, expressed as difference in Hb, did not differ between the groups.

Conclusion: In an elderly population with FNFs, we found that the DAA, compared with the DLA, results in less CK and CRP increase, but no change in Hb.