Piriformis-Sparing Minimally Invasive Versus the Standard Posterior Approach for Total Hip Arthroplasty: A 10-Year Follow-Up of a Randomized Control Trial

J Arthroplasty. 2019 Feb;34(2):319-326. doi: 10.1016/j.arth.2018.10.014. Epub 2018 Oct 17.


Background: Despite the popularity of minimally invasive approaches in total hip arthroplasty, studies regarding their impact on soft tissues and long-term benefits are lacking. This study aims to compare the 10-year functional outcome of the piriformis-sparing minimally invasive approach to the standard posterior approach for total hip arthroplasty surgery.

Methods: Hundred patients were randomized, 48 patients to the piriformis-sparing approach and 52 to the standard approach. Primary outcomes were hip function and piriformis muscle volume and grade on magnetic resonance imaging. Secondary outcomes were pain, satisfaction score, and complications. Evaluators were blinded to allocation. Participants were followed up to 10 years.

Results: Ten years following surgery, both groups reported excellent pain relief, improved hip function, and high satisfaction. The significant differences were improvement in piriformis muscle volume (P = .001) and muscle grade (P = .007) in the piriformis-sparing group compared to the standard group. There were no significant differences in all other outcomes.

Conclusion: Aside from being less injurious to the piriformis muscle, the piriformis-sparing approach offered the same long-term functional benefits as the standard posterior approach at 10 years.

Keywords: arthroplasty; hip; piriformis-sparing minimally invasive; posterior approach; short external rotators.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Arthroplasty, Replacement, Hip / methods
  • Arthroplasty, Replacement, Hip / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Hip / surgery
  • Hip Joint / diagnostic imaging
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Minimally Invasive Surgical Procedures / methods
  • Muscle, Skeletal
  • Organ Sparing Treatments / statistics & numerical data*
  • Osteoarthritis, Hip / surgery
  • Recovery of Function