Purpose: Despite their inclusion within clinical practice, standardized radiographs may not accurately project an individual’s level of function and mobility. The purpose of this study is to examine the potential relationship between established radiographic features and lurch; a functional measure of asymmetric gait, in a group of patients who will receive total hip arthroplasty (THA).
Method: Thirty-two patients (16 females, 16 males) identified as hip replacement candidates were recruited, with a mean age of 57.0 years. Lurch was obtained using the Walkabout Portable Gait Monitor (WPGM); a wireless, triaxial accelerometry device. The independent variables were comprised of the Kellgren-Lawrence Scale, and a collection of standard radiographic features, as adopted by the American Academy of Orthopaedic Surgeons (AAOS), the National Institutes of Health (NIH), and the World Health Organization (WHO). Radiographs were blinded, and the surgeon completing the rating scale was unaware of patient’s lurch values. Age-adjusted regression analyses were used to examine the potential association between each radiographic feature and lurch.
Results: Increased amounts of lurch (i.e. functional impairment) were independently associated with higher Kellgren-Lawrence Scale scores (p=.047), increased Joint Space Narrowing in the mid-portion of the joint (zone 2; p=.004), the presence of acetabular wear (p=.045), an increased severity of subchondral femoral head cysts (p=.004), and higher surgeon-rated Visual Analog Scale scores for overall severity of joint degeneration (p=.008). Lurch was not significantly associated with the remaining 10 features which were examined. Further analyses revealed that lurch was not significantly associated with certain demographic factors, including sex, Body Mass Index, and co-morbid health conditions.
Conclusion: Although the Kellgren-Lawrence scale was associated with an objective measure of gait, our results indicate that other radiographic features may provide a more accurate prediction of gait performance among this patient population. As lurch appears to be a robust objective measure of physical impairment, which is unaffected by BMI and co-morbidities, we believe that portable triaxial accelerometers can likely be used to conveniently collect objective gait data. This functional data may be used to supplement clinical efforts to screen and prioritize appropriate hip arthroplasty patients.
