Does Long-Term Lower Extremity Strength Training in Adults With Knee Osteoarthritis and Varus Alignment Reduce Knee...

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Knee osteoarthritis (OA) is a degenerative joint disease often associated with knee malalignment.
• Medial tibiofemoral osteoarthritis is frequently observed in individuals with knee varus alignment.
• Strength training is a common intervention for knee OA, but its effect on joint loading in malaligned knees is less understood.

Purpose of the Study:

• To determine if 18 months of strength training reduces knee joint loads during walking in individuals with knee varus alignment and medial tibiofemoral OA.
• To compare knee joint loading parameters between a strength training group and an attention control group.

Main Methods:

• Secondary analysis of a randomized clinical trial involving adults with knee OA and varus malalignment (≥2 degrees).
• Strength training group (N=39) achieved ≥20% increase in hip abductor strength over 18 months.
• Control group (N=49) received attention control.
• Linear regressions compared group means at 18-month follow-up.

Main Results:

• Strength training significantly increased quadriceps (45%), hamstring (68%), and hip abductor (42%) strength compared to controls (16%, 11%, 4%).
• No significant differences were found in peak knee abduction moment or peak knee compressive force between groups.
• A significant 27% reduction in the internal knee extension moment was observed in the strength training group (P=0.03).

Conclusions:

• Long-term lower extremity strength training significantly increases muscle strength in older adults with knee OA and varus alignment.
• Most measures of knee joint loading during walking were not significantly altered by strength training compared to an attention control group.
• The study questions whether clinically meaningful improvements in muscle strength translate to clinically important reductions in knee joint loading.