A lower extremity physical function computerized adaptive testing instrument for orthopaedic patients.

Area of Science:

• Orthopedics
• Biomedical Engineering
• Health Outcomes Research

Background:

• Developing efficient patient-reported outcome measures is crucial in orthopedics.
• Existing tools may not fully capture lower extremity (LE) physical function nuances.
• The Patient Reported Outcomes Measurement Information System (PROMIS) offers a robust item bank for adaptation.

Purpose of the Study:

• To develop a computerized adaptive testing (CAT) instrument for lower extremity (LE) physical function.
• To base the new instrument on the PROMIS physical function item bank.
• To create a valid, reliable, and feasible assessment tool for orthopedic patients.

Main Methods:

• Administered the PROMIS physical function item bank to 382 adult orthopedic patients with LE disorders.
• Utilized item response theory (IRT) modeling to develop a specialized LE physical function item bank.
• Conducted computerized adaptive testing (CAT) simulations using real patient data.

Main Results:

• The developed LE physical function item bank demonstrated unidimensionality and was free of item bias.
• The instrument exhibited high reliability, content validity, and construct validity.
• The flexible-length LE CAT showed high correlation with the full instrument and uniform precision, averaging 6-7 items for a standard error of 0.3 or less.

Conclusions:

• The LE physical function CAT is a valid, reliable, and feasible assessment tool for orthopedic patients with LE conditions.
• This CAT has the potential to significantly reduce patient burden during data collection.
• The instrument may lead to reduced administrative costs associated with physical function assessments.