Determining Clinically Meaningful Thresholds for the Nonarthritic Hip Score in Patients Undergoing Arthroscopy for Femoroacetabular Impingement Syndrome
Authors: Rosinsky PJ, Kyin C, Maldonado DR, Shapira J, Meghpara MB, Ankem HK, Lall AC, Domb BG
DOI: 10.1016/j.arthro.2021.03.059
Background
The Nonarthritic Hip Score (NAHS) is a validated tool to assess hip function in patients with femoroacetabular impingement (FAI). However, thresholds defining clinically meaningful improvements and acceptable states after hip arthroscopy were unclear.
Methods
343 hips undergoing hip arthroscopy were followed, with NAHS collected preoperatively and at 1, 2, and 5 years postoperatively. The study calculated:
- Minimal clinically important difference (MCID)
- Patient acceptable symptomatic state (PASS)
- Substantial clinical benefit (SCB)
Key Findings
- MCID = 8.7 points increase in NAHS
- PASS ranged from 81.9 to 85.6, indicating the score above which patients consider themselves well
- SCB ranged from 91.9 to 94.4, indicating excellent recovery
- Higher preoperative NAHS was associated with better postoperative outcomes
Conclusions
These clinically meaningful thresholds allow for better interpretation of NAHS results to determine patient recovery status after hip arthroscopy.
What Does This Mean for Providers?
- Use these thresholds to interpret NAHS scores more accurately when assessing patient recovery.
- Consider MCID (8.7 points improvement) as the minimal target for meaningful clinical change.
- Utilize PASS and SCB thresholds to set expectations and guide postoperative decision-making.
- Recognize that patients with higher preoperative function tend to achieve better outcomes, which may inform surgical candidacy discussions.
- Incorporate these benchmarks in patient counseling and outcome monitoring for personalized care.