FORT LAUDERDALE, FLA. – The walk of a patient with osteoarthritis differs by which knee compartments are affected, according to researchers who linked radiographic findings with sophisticated motion analysis.
Knee osteoarthritis (OA) leads to alterations in gait that can further impair function for patients, Dr. William F. Harvey said at the World Congress on Osteoarthritis. To find out if there are gait alterations unique to the compartments of the knee that are affected by OA, Dr. Harvey and his associates assessed 448 patients in North Carolina enrolled in the Observational Arthritis Study in Seniors (OASIS).
Participants' mean age was 72 years and all were more than 65 years old; all reported knee pain. Just more than half, 51%, were women; 83% were white; and the mean body mass index was 30 kg/m
At baseline, researchers found that 166 patients had grade 0 Kellgren-Lawrence (KL), 51 patients had grade 1 KL, 47 patients had grade 2 KL, 126 patients had grade 3 KL, and 58 patients had grade 4 KL; in general, the higher the KL grade, the worse the meniscal pathology and chondral degradation, Dr. Harvey, a fellow in rheumatology at Boston University, said at the meeting, which was sponsored by the Osteoarthritis Research Society International.
Kinematic measures of gait were performed during self-paced walking in the sagittal plane only, with outcomes based on an average of three trials. Peak angular range of motion, mean angular velocity (of the hip, knee, and ankle joints), stride length, walking velocity, cadence, and stance and swing times were measured. Mean values were compared between groups. Results were adjusted for age, race, gender, body mass index, and walking velocity.
Patients with isolated tibio-femoral (159 participants), and both tibiofemoral and patellofemoral osteoarthritis (72 participants) had a significantly lower knee range of motion and mean angular velocity, compared with those with no osteoarthritis (206 participants), Dr. Harvey said. The mean knee range of motion angle was 54 degrees in the tibiofemoral group and 53 degrees in the combined group, compared with 57 degrees in the unaffected group. The mean value for the patellofemoral osteoarthritis group, 58 degrees, was not statistically significant because of the small number of patients in the category.
In addition, there was a statistically significant difference in mean angular velocity of the knee between the same groups. Those with tibiofemoral osteoarthritis and both compartments affected had a lower mean angular velocity, compared with those without osteoarthritis, Dr. Harvey said. Expressed as degrees per second, the values were 104 in the tibiofemoral group, 100 in the group with both compartments affected, and 117 in the comparison, disease-free, group without disease. Again, the 110 degrees per second finding in the patellofemoral group was not significant.
Stance time was another variable that was significantly different between groups. The patellofemoral group and doubly affected group spent more time in stance versus swing, compared with the tibiofemoral osteoarthritis group or the unaffected patients.
The study was funded by Wake Forest University and a grant from the National Institutes of Health.
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