Chondroitin Sulfate Improves Knee OA Symptoms and Walking

Key Takeaways

• Adults with symptomatic KL grade II knee osteoarthritis at a single South Korean center had significantly greater improvement in knee symptom and function scores with chondroitin sulfate than with placebo.
• Self-reported knee pain and timed walking both favored chondroitin sulfate.
• Hand symptom and strength measures also favored chondroitin sulfate, but participants were enrolled for knee osteoarthritis.
• No adverse events were reported in either group during the intervention.

Radiographically mild knee osteoarthritis can still cause pain and restrict mobility. For adults considering chondroitin sulfate, the question Baek and Park assessed was whether changes in perceived knee symptoms align with measured walking performance.

Baek and Park enrolled 100 adults, 50 per group, for their randomized trial at Woosuk University Korean Medicine Hospital in South Korea. The single-center, double-blind, parallel-group trial compared chondroitin sulfate with matching placebo. Participants were aged 45–74 years and had radiographically confirmed Kellgren–Lawrence (KL) grade II knee osteoarthritis and screening knee-pain visual analog scale (VAS) scores of 40–70 mm on a 100-mm scale. They took two 600-mg chondroitin sulfate tablets (1200 mg/day) or matching placebo once daily for 12 weeks. Primary outcomes were Korean Western Ontario and McMaster Universities Osteoarthritis Index (K-WOMAC) total, pain, stiffness, and physical-function scores. Secondary assessments included pain VAS, timed 20-m walking, Korean Australian/Canadian Osteoarthritis Hand Index (K-AUSCAN) outcomes, and bilateral grip and pinch strength. The main efficacy analysis was per protocol; an additional full-analysis-set analysis included the same enrolled participants.

At week 12, K-WOMAC total scores changed by −19.26 ± 2.74 points with chondroitin sulfate versus −2.10 ± 1.37 points with placebo (p < 0.001). Pain, stiffness, and physical-function subscale changes also favored chondroitin sulfate at weeks 6 and 12. Total and pain subscale scores differed between arms at baseline, but baseline-adjusted between-group changes remained significant at both follow-ups.

At week 12, pain VAS changed by −18.82 ± 3.50 versus −3.04 ± 3.10 mm, and 20-m walking time changed by −1.40 ± 0.62 versus +0.23 ± 0.32 seconds, with chondroitin sulfate versus placebo in both comparisons (both p < 0.001). Both measures favored chondroitin sulfate at week 6 as well. K-AUSCAN total and subscale scores and bilateral grip and pinch strength also favored chondroitin sulfate. All 100 randomized participants completed the trial and comprised both efficacy analysis sets. No adverse events were reported in either arm, and laboratory tests and vital signs showed no clinically meaningful changes during the intervention.

Enrollment at one South Korean center was restricted by radiographic grade, pain severity, body mass index, comorbidities, and concurrent treatments; women predominated. Symptom and functional assessments over 12 weeks cannot establish durability, and the absence of knee structural imaging precludes conclusions about cartilage preservation or disease modification. Hand measures were secondary outcomes in adults recruited for knee rather than hand osteoarthritis, while grip and pinch changes do not establish direct muscle strengthening. Registration after enrollment began limits prospective public verification of prespecified information. The absence of reported adverse events applies only to the monitored period, not to longer-term safety.

According to the researchers, chondroitin sulfate was associated with short-term improvements in reported knee symptoms and measured walking relative to placebo in this selected KL grade II population.

Clinician Questions

Which pain VAS measurement served as baseline for chondroitin sulfate outcomes in knee osteoarthritis?

In Baek and Park’s trial of chondroitin sulfate versus placebo among adults with KL grade II knee osteoarthritis, the knee-pain VAS measured at screening served as the analysis baseline for pain comparisons, rather than the subsequent baseline-visit measurement. Screening pain also determined eligibility.

How was timed 20-m walking assessed in the chondroitin sulfate knee osteoarthritis trial?

For adults with KL grade II knee osteoarthritis receiving chondroitin sulfate or placebo, investigators timed walking at the participants’ usual pace over a straight 20-m course on three consecutive trials and analyzed their mean. An assistive device was permitted if the same device was used at each assessment.