Single-step test for unilateral limb ability following total knee arthroplasty

Area of Science:

• Orthopedics
• Rehabilitation Medicine
• Biomechanical Engineering

Background:

• Current functional tests after total knee arthroplasty (TKA) do not isolate the surgical limb's contribution.
• A unilateral limb assessment is needed to accurately evaluate the affected extremity post-TKA.

Purpose of the Study:

• Evaluate the single-step test (SST) for intertester reliability, validity, and responsiveness in post-TKA patients.
• Determine if SST can differentiate between surgical and non-surgical limbs, and between TKA patients and healthy controls.

Main Methods:

• Secondary analysis of a prospective, randomized, longitudinal clinical trial cohort.
• Assessed intertester reliability between clinicians and with a switch mat.
• Tested patients at initial evaluation, 3 months, and 1 year post-unilateral TKA.

Main Results:

• SST demonstrated reliable intertester results with a stopwatch.
• SST times correlated significantly with other functional measures, confirming validity.
• SST showed responsiveness to treatment and differentiated between limbs in TKA patients and controls.

Conclusions:

• The single-step test is a reliable, valid, and responsive measure for activity limitations post-TKA.
• SST effectively assesses unilateral lower extremity impairments in patients following total knee arthroplasty.