Reliability, validity, and responsiveness of the lower extremity measure for patients with a hip fracture

Background: The purpose of this study was to determine whether currently pu blished outcome measures of physical function would be suitable for use for older adults,vith a hip fracture. The measures that were considered were t he Musculoskeletal Function Assessment (MFA) Instrument, the Older American s' Resources and Services (OARS) Multidimensional Functional Assessment Que stionnaire physical function subscale, the Toronto Extremity Salvage Score (TESS), and the Short Form-36 (SF-36), Following suggestions by an expert p anel and patient interviews, the MFA was not tested further. The TESS was m odified and renamed the Lower Extremity Measure (LEM). Methods: Forty-three community-dwelling patients with a hip fracture comple ted the LEM, OARS, and SF-36 in the hospital so that the prefracture status could be obtained; they were then followed prospectively at six weeks and at six months. All patients were interviewed twice in the hospital to asses s the reliability of the LEM (intraclass correlation coefficient = 0.85). T o establish criterion validity, the measures were compared with the Timed U p and Go (TUG) test at six weeks. We tested a number of hypotheses to deter mine construct validity. Results: Only the LEM scores were significantly correlated with the TUG sco res (r = -0.53, p = 0.03). The LEM scores were significantly correlated wit h the SF-36 subscale scores and the OARS scores. Patients with at least one comorbidity had a lower mean prefracture LEM score (90.0 +/- 9.7) than pat ients,vith no comorbidity (96.9 +/- 8.1) (p = 0.02). Patients who had used no walking aids before the fracture had a higher mean prefracture LEM score than those who had used a cane (95.5 +/- 5.8 compared with 85.5 +/- 12.7; p = 0.0007). Both the LEM and the SF-36 scores changed significantly betwee n all of the time-periods (p < 0.05). Measures of responsiveness indicated that the LEM was the best measure for detecting changes in physical functio n. Conclusions: The LEM can detect clinically important changes in physical fu nction over time in patients with a hip fracture and would be most useful f or clinical trials or cohort studies. Orthopaedists who are currently utili zing the SF-36 can be reassured that the physical function subscale is a va lid measure for patients with a hip fracture.