Objective  To investigate the effect of minimally invasive total hip arthroplasty (THA) through direct anterior approach (DAA) in treatment of elderly femoral neck fractures and its effect on early postoperative balance function and bone metabolism.

Methods  A total of 84 elderly patients with femoral neck fracture were prospectively selected and randomly divided into observation group and control group, with 42 cases in each group. The control group was given THA by the posterolateral approach (PLA), and the observation group was given THA by the minimally invasive DAA approach for THA. The perioperative indexes, early postoperative hip function and balance function, bone metabolism indexes osteocalcin (OC), type Ⅰ collagen C-terminal peptide (CTX), 25 hydroxyvitamin D25 (OH) D, type Ⅰ procollagen N-terminal peptide (PINP) and bone-specific alkaline phosphatase (BALP) and complications were compared between the two groups.

Results  There was no significant difference in the operation time between the two groups(P>0.05). The intraoperative blood loss and hospitalization time in the observation group were significantly less than or shorter than those in the control group (P < 0.05). Compared with before surgery, the Harris score, Berg score, Tinetti score, OC, 25(OH)D and BALP levels were significantly increased, while CTX and PINP levels were significantly decreased in two groups at 3 months after surgery (P < 0.05). Compared with the control group, the Harris score, Berg score, Tinetti score, OC, 25(OH)D and BALP levels in the observation group were significantly increased, while the CTX and PINP levels were significantly decreased (P < 0.05). The incidence of postoperative complications in the observation group was 2.38%, which was significantly lower than 19.05% in the control group (P < 0.05).

Conclusion THA with minimally invasive DAA for the treatment of femoral neck fracture has small incision, little trauma and low incidence of postoperative complications, which can promote early recovery of hip function and balance function, and improve bone metabolism.