Abstract
PURPOSE/HYPOTHESIS: Contralateral pelvic drop during the single-limb support phase of walking can increase the external knee adduction moment and load the medial tibiofemoral (TF) compartment. The purpose of this study was to determine the relationship between pelvic drop during usual and fast-paced walking and the prevalence of radiographic and symptomatic medial tibiofemoral (TF) osteoarthritis (OA) in older adults. We hypothesized that the prevalence of medial TF OA would be greater among limbs with greater pelvic drop and that this relationship would be stronger during fast than usual-paced walking.
NUMBER OF SUBJECTS: Ninety-six participants with available pelvic drop measurements contributed 173 limbs for analysis.
MATERIALS/METHODS: The Multicenter Osteoarthritis Study (MOST) includes older adults who have or are at-risk of knee OA. Participants in the 60-month exam wore pelvic markers on the anterior superior iliac spines (ASISs) during 2 walking trials on a 14-ft instrumented walkway at self-selected usual and fast paces. Synchronized sagittal and frontal plane videos (60 Hz) were acquired to measure mean pelvic drop in an-gular degrees during sampled steps when the swing and stance thighs were parallel. Pelvic drop was defined as the frontal plane angle between a horizontal reference line and a line connecting the ASIS markers. An inferior movement of the left ASIS while weight bearing on the right limb constituted a positive pelvic drop angle for the right limb. Limbs with radiographic medial TF OA (ROA) had K&L grade of greater than or equal to 2 on a fixed flexion X-ray with OARSI medial joint space narrowing score of greater than or equal to 1 and greater medially than laterally. Limbs with total hip/knee replacement were excluded. Limbs with symptomatic medial TF OA (SOA) had medial ROA with knee pain most days. Limbs were categorized in groups of increasing pelvic drop using the tertile distribution among cases of ROA and SOA to define cutpoints. The relative odds of ROA and SOA in each category were determined using logistic regression with generalized estimating equations while adjusting for age, sex, BMI, walking velocity, and clinic site. A test for linear trend assessed dose-response relationships. Analyses were repeated for usual and fast-paced walking.
RESULTS: Mean pelvic drop was 2.4° (±) 3.2° at usual speed, and 3.1° (±) 3.4°at fast speed. Increasing pelvic drop during usual and fast walking was associated with moderate (1.3 to 2.1 times) increases in the odds of both ROA (P for trend = .21 at usual pace and .06 at fast pace) and SOA (P for trend = .15 at usual pace and .49 at fast pace), although these trends were not statistically significant.
CONCLUSIONS: Nonsignificant trends in the data are consistent with the assertion that increasing pelvic drop is associated with an increasing prevalence of radiographic and symptomatic medial TF OA. A larger study sample is needed to clarify these findings.
CLINICAL RELEVANCE: Pelvic drop during walking is potentially modifiable and may be associated with an increased odds of medial knee OA in older adults.
NUMBER OF SUBJECTS: Ninety-six participants with available pelvic drop measurements contributed 173 limbs for analysis.
MATERIALS/METHODS: The Multicenter Osteoarthritis Study (MOST) includes older adults who have or are at-risk of knee OA. Participants in the 60-month exam wore pelvic markers on the anterior superior iliac spines (ASISs) during 2 walking trials on a 14-ft instrumented walkway at self-selected usual and fast paces. Synchronized sagittal and frontal plane videos (60 Hz) were acquired to measure mean pelvic drop in an-gular degrees during sampled steps when the swing and stance thighs were parallel. Pelvic drop was defined as the frontal plane angle between a horizontal reference line and a line connecting the ASIS markers. An inferior movement of the left ASIS while weight bearing on the right limb constituted a positive pelvic drop angle for the right limb. Limbs with radiographic medial TF OA (ROA) had K&L grade of greater than or equal to 2 on a fixed flexion X-ray with OARSI medial joint space narrowing score of greater than or equal to 1 and greater medially than laterally. Limbs with total hip/knee replacement were excluded. Limbs with symptomatic medial TF OA (SOA) had medial ROA with knee pain most days. Limbs were categorized in groups of increasing pelvic drop using the tertile distribution among cases of ROA and SOA to define cutpoints. The relative odds of ROA and SOA in each category were determined using logistic regression with generalized estimating equations while adjusting for age, sex, BMI, walking velocity, and clinic site. A test for linear trend assessed dose-response relationships. Analyses were repeated for usual and fast-paced walking.
RESULTS: Mean pelvic drop was 2.4° (±) 3.2° at usual speed, and 3.1° (±) 3.4°at fast speed. Increasing pelvic drop during usual and fast walking was associated with moderate (1.3 to 2.1 times) increases in the odds of both ROA (P for trend = .21 at usual pace and .06 at fast pace) and SOA (P for trend = .15 at usual pace and .49 at fast pace), although these trends were not statistically significant.
CONCLUSIONS: Nonsignificant trends in the data are consistent with the assertion that increasing pelvic drop is associated with an increasing prevalence of radiographic and symptomatic medial TF OA. A larger study sample is needed to clarify these findings.
CLINICAL RELEVANCE: Pelvic drop during walking is potentially modifiable and may be associated with an increased odds of medial knee OA in older adults.
Original language | English |
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Article number | OPL7 |
Pages (from-to) | A16-A17 |
Number of pages | 2 |
Journal | Journal of Orthopaedic & Sports Physical Therapy |
Volume | 42 |
Issue number | 1 |
DOIs | |
Publication status | Published - Feb 2012 |
Event | CSM 2012 - Combined Section Meeting of American Physical Therapy Association - Chicago, United States Duration: 8 Feb 2012 → 11 Feb 2012 |