Plain language summary
Obesity is a common contributor to knee joint arthritis. In a previous trial, called the Intensive Diet and Exercise for Arthritis (IDEA) trial, it was demonstrated that 18 months of weight loss via a combination of diet and exercise was superior to diet alone for improved clinical outcomes in 454 individuals with knee joint arthritis. This sub analysis of the original randomised control trial, aimed to determine if weight loss due to diet plus exercise was more beneficial than weight loss due to diet or exercise alone to the way a person walked with knee joint arthritis. The results showed that weight loss was greatest amongst the diet and exercise group, then the diet group, and finally the exercise group. The diet and exercise group walked faster than either the diet or exercise alone groups. Dietary weight loss resulted in improved pressure upon the hip, knee and ankle joints, which was attenuated with a combination of diet and exercise. It was concluded that dietary weight loss was more beneficial for knee joint arthritis, however dietary weight loss combined with exercise is still superior to exercise alone. This study could be used by healthcare professionals to recommend a dietary weight loss regime for individuals with knee arthritis in order to improve their ability to walk.
Abstract
The Intensive Diet and Exercise for Arthritis (IDEA) trial was an 18-month randomized controlled trial that enrolled 454 overweight and obese older adults with symptomatic and radiographic knee osteoarthritis (OA). Participants were randomized to either exercise (E), intensive diet-induced weight loss (D), or intensive diet-induced weight loss plus exercise (D + E) interventions. We previously reported that the clinical benefits of D + E were significantly greater than with either intervention alone (e.g., greater pain reduction, and better function, mobility, and health-related quality of life). We now test the hypothesis that D + E has greater overall benefit on gait mechanics compared to either intervention alone. Knee joint loading was analyzed using inverse dynamics and musculoskeletal modeling. Analysis of covariance determined the interventions' effects on gait. The D + E group walked significantly faster at 18-month follow-up (1.35 m s-1) than E (1.29 m s-1, p = 0.0004) and D (1.31 m s-1, p = 0.0007). Tibiofemoral compressive impulse was significantly lower (p = 0.0007) in D (1069 N s) and D + E (1054 N s) compared to E (1130 N s). D had significantly lower peak hip external rotation moment (p = 0.01), hip abduction moment (p = 0.0003), and peak hip power production (p = 0.016) compared with E. Peak ankle plantar flexion moment was significantly less (p < 0.0001) in the two diet groups compared with E. There also was a significant dose-response to weight loss; participants that lost >10% of baseline body weight had significantly (p = 0.0001) lower resultant knee forces and lower muscle (quadriceps, hamstring, and gastrocnemius) forces than participants that had less weight loss. Compared to E, D produces significant load reductions at the hip, knee, and ankle; combining D with E attenuates these reductions, but most remain significantly better than with E alone.
Methodological quality
Jadad score
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1
Allocation concealment
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No
