A Way to Relieve Pain in Osteoarthritis?
A Way to Relieve Pain in Osteoarthritis?
Lo GH, Harvey WF, McAlindon TE
Arthritis Rheum. 2012;64:2252-2259
Multiple factors can lead to symptomatic osteoarthritis (OA); these include collagen defects, mechanical injury, and systemic and local inflammation. Furthermore, in a patient with OA, multiple factors can contribute to pain, including biomechanical strain on the joint and surrounding tissues, bone injury, inflammation, and synovitis. Given the growing numbers of individuals with symptomatic OA, identifying potential targets for treatments to improve pain are welcome.
Lo and colleagues evaluated the role of biomechanical abnormalities on pain in 82 patients with established knee OA who were enrolled in a trial of vitamin D in knee OA. They assessed 2 mechanical factors: (1) static alignment, on the basis of radiographs, with varus alignment less than 178° considered normal, and (2) varus thrust, which is defined as the first appearance of varus or worsening varus with weight-bearing ambulation, evaluated during visualization of ambulation either directly or through video recording. Pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
They found that 25 (31%) of studied patients had definite varus thrust, and these patients had a higher mean body weight than those without varus thrust (89 kg vs 81 kg; P = .06). Radiographic OA was also worse in patients with varus thrust.
WOMAC pain scores were significantly worse in patients with varus thrust than in those who did not have varus thrust, although this difference lost statistical significance after adjustment for age, sex, height, weight, and walking speed. Abnormal static alignment of the knee, using radiographic measurements and considering varus alignment less than 178° as normal, as well as alignments of 171-180°, were not significantly associated with higher pain levels.
Lo and colleagues concluded that in patients with OA, the presence of varus thrust is associated with pain, and they speculated that treatment of varus thrust could lead to symptom improvement.
The association of the biomechanical abnormality of varus thrust with pain in this small study of a subset of patients with OA is of interest. We should look forward to larger studies to confirm these findings, as well as studies to determine whether interventions that improve varus thrust improve pain and function, slow progression of OA, and prevent disease in individuals at risk. Furthermore, if assessment and treatment of varus thrust abnormalities prove to be meaningful in the management of OA, we will need easily implemented, highly reproducible methods to identify and correct this abnormality.
Abstract
Associations of Varus Thrust and Alignment With Pain in Knee Osteoarthritis
Lo GH, Harvey WF, McAlindon TE
Arthritis Rheum. 2012;64:2252-2259
Pain in Osteoarthritis
Multiple factors can lead to symptomatic osteoarthritis (OA); these include collagen defects, mechanical injury, and systemic and local inflammation. Furthermore, in a patient with OA, multiple factors can contribute to pain, including biomechanical strain on the joint and surrounding tissues, bone injury, inflammation, and synovitis. Given the growing numbers of individuals with symptomatic OA, identifying potential targets for treatments to improve pain are welcome.
Study Summary
Lo and colleagues evaluated the role of biomechanical abnormalities on pain in 82 patients with established knee OA who were enrolled in a trial of vitamin D in knee OA. They assessed 2 mechanical factors: (1) static alignment, on the basis of radiographs, with varus alignment less than 178° considered normal, and (2) varus thrust, which is defined as the first appearance of varus or worsening varus with weight-bearing ambulation, evaluated during visualization of ambulation either directly or through video recording. Pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
They found that 25 (31%) of studied patients had definite varus thrust, and these patients had a higher mean body weight than those without varus thrust (89 kg vs 81 kg; P = .06). Radiographic OA was also worse in patients with varus thrust.
WOMAC pain scores were significantly worse in patients with varus thrust than in those who did not have varus thrust, although this difference lost statistical significance after adjustment for age, sex, height, weight, and walking speed. Abnormal static alignment of the knee, using radiographic measurements and considering varus alignment less than 178° as normal, as well as alignments of 171-180°, were not significantly associated with higher pain levels.
Lo and colleagues concluded that in patients with OA, the presence of varus thrust is associated with pain, and they speculated that treatment of varus thrust could lead to symptom improvement.
Viewpoint
The association of the biomechanical abnormality of varus thrust with pain in this small study of a subset of patients with OA is of interest. We should look forward to larger studies to confirm these findings, as well as studies to determine whether interventions that improve varus thrust improve pain and function, slow progression of OA, and prevent disease in individuals at risk. Furthermore, if assessment and treatment of varus thrust abnormalities prove to be meaningful in the management of OA, we will need easily implemented, highly reproducible methods to identify and correct this abnormality.
Abstract
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