Is There a Learning Curve for the 5-Year Implant Survival Rate of Total Hip Arthroplasty Using the Direct Anterior Approach With a Traction Table? A Prospective Cohort Study

Junichi Nakamura; Shigeo Hagiwara; Yuya Kawarai; Rui Hirasawa; Tsutomu Akazawa; Seiji Ohtori

doi:10.1016/j.arth.2024.04.080

Is There a Learning Curve for the 5-Year Implant Survival Rate of Total Hip Arthroplasty Using the Direct Anterior Approach With a Traction Table? A Prospective Cohort Study

J Arthroplasty. 2024 May 4:S0883-5403(24)00428-5. doi: 10.1016/j.arth.2024.04.080. Online ahead of print.

Authors

Junichi Nakamura¹, Shigeo Hagiwara¹, Yuya Kawarai¹, Rui Hirasawa¹, Tsutomu Akazawa², Seiji Ohtori¹

Affiliations

¹ Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chiba city, Chiba, Japan.
² Department of Orthopedic Surgery, St. Marianna University, Kawasaki city, Kanagawa, Japan.

PMID: 38710345
DOI: 10.1016/j.arth.2024.04.080

Abstract

Background: The direct anterior approach (DAA) for total hip arthroplasty (THA) is attracting attention as a minimally invasive surgery, but the learning curve to master this approach is a concern, and its effect on long-term results is unknown. The purpose of this prospective cohort study was to clarify how the learning curve affects the 5-year results of DAA THA with a traction table.

Methods: Of 402 THA cases using DAA with a mobile traction table and fluoroscopy, 249 cases composed of the first 50 cases for each surgeon were assessed during a learning curve, and 153 cases were evaluated after more than 50 cases of experience.

Results: The 5-year-implant survival rate was 99.2% both during and after the learning curve. The 2-year complication rate in the learning curve group was 8.9 versus 5.9%, which was not statistically significant. The 2-to-5-year complication rates also did not differ between the cohorts (0 versus 0.7%). Both groups demonstrated decreased complication rates when comparing 2-year complications to 2-to-5-year complications. Clinical scores significantly improved by 2 years and were maintained at 5 years in both groups. The cup safe-zone success rates were 96.4% during the learning curve and 98.7% after the learning curve. The stem safe-zone success rates were 97.2% during the learning curve and 96.1% after the learning curve. Surgical time was approximately 20 minutes shorter after the first 50 cases than during the learning curve (70.8 versus 90.6 minutes, P = .001). Intraoperative blood loss was significantly less after the learning curve than during the learning curve.

Conclusions: This study implies that the learning curve affects perioperative results such as surgical time and intraoperative blood loss, but has little effect on short-term results up to 2 years after surgery and no effect on mid-term results from 2 to 5 years after surgery.

Keywords: 5-year results; direct anterior approach; learning curve; prospective cohort study; total hip arthroplasty; traction table.