Biomarkers of muscle damage increased in anterolateral compared to direct lateral approach to the hip in hemiarthroplasty: no correlation with clinical outcome : Short-term analysis of secondary outcomes from a randomized clinical trial in patients with a displaced femoral neck fracture.

In this study, we found elevated levels of serum CK in the anterolateral approach to the hip compared to the direct lateral approach in patients with a displaced femoral neck fracture. No correlation was found between levels of CK and functional outcomes.

INTRODUCTION: To compare increase in serum creatine kinase (CK) and its association with functional outcome between the muscle-sparing anterolateral approach and the direct lateral approach to the hip in patients with displaced femoral neck fracture (FNF).

METHODS: In this randomized trial, we enrolled eligible patients between 70 and 90 years of age with FNF. Patients were allocated to an uncemented hemiarthroplasty inserted through a direct lateral or an anterolateral approach. The primary endpoints were pain and patient satisfaction assessed by the Visual Analogue Scale (VAS). Among secondary endpoints was increase in CK at 24 and 48 h compared to baseline and its association with surgical parameters, Timed up and Go Test (TUG), Harris Hip Score (HHS), and the presence of a Trendelenburg sign using correlation analysis. This paper reports on increase in serum CK and its association with functional outcome.

RESULTS: At 24 h, there was a mean increase from baseline in total CK of 228 U/L (95% CI 187 to 269; P < 0.001). There was a difference between groups at 24 h in CK increase with higher levels in the anterolateral group (mean difference 80 U/L; 95% CI - 0.5 to 162; P = 0.05). Likewise, at 48 h, there was a mean difference of 117 U/L (95% CI 22 to 212; P = 0.01). No correlation was found between CK values and functional assessments.

CONCLUSIONS: Compared with the direct lateral approach, the anterolateral approach yielded higher levels of postoperative CK. However, there was no correlation between levels of CK and functional outcome.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02028468.