Which statement about the LEFS is true?

Which statement about the LEFS is true?

• A. MDC 9 and MCID 6
• B. MDC 9 and MCID 9
• C. MDC 9 and MCID 12
• D. MDC 6 and MCID 9

Answer: (B)

Understanding how to interpret LEFS changes revolves around two ideas: what change is beyond the tool’s measurement error (MDC) and what change patients actually feel as a meaningful improvement (MCID). The LEFS runs from 0 to 80, with higher scores indicating better function. The MDC at 95% confidence for LEFS is about nine points, meaning a change of that magnitude is unlikely to be due to measurement noise. The MCID for LEFS in knee-related conditions is also around nine points, so a nine-point improvement is typically enough for patients to recognize a real, meaningful benefit. Because a nine-point change meets both criteria—it's large enough to exceed measurement error and large enough to be clinically meaningful—it best matches the established interpretation for LEFS. Smaller or larger values for MCID, or a discordant MDC, don’t align as well with the common thresholds used in practice.

Understanding how to interpret LEFS changes revolves around two ideas: what change is beyond the tool’s measurement error (MDC) and what change patients actually feel as a meaningful improvement (MCID). The LEFS runs from 0 to 80, with higher scores indicating better function. The MDC at 95% confidence for LEFS is about nine points, meaning a change of that magnitude is unlikely to be due to measurement noise. The MCID for LEFS in knee-related conditions is also around nine points, so a nine-point improvement is typically enough for patients to recognize a real, meaningful benefit. Because a nine-point change meets both criteria—it's large enough to exceed measurement error and large enough to be clinically meaningful—it best matches the established interpretation for LEFS. Smaller or larger values for MCID, or a discordant MDC, don’t align as well with the common thresholds used in practice.