In October 2008, Arthritis & Rheumatism published a study on the effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis. Osteoarthritis, the most common form of arthritis, currently affects 27 million of the 46 million people in the United States with arthritis. Recent data show that one in two Americans are at risk for knee osteoarthritis over their lifetime. The image depicts a model of a healthy knee joint.

In this study, patients with well established osteoarthritis were randomized to treatment with standard doses of glucosamine, chondroitin, the combination of glucosamine and chondroitin, celecoxib, or placebo.

Previous findings from this study suggest evidence that glucosamine and chondroitin were no better than placebo in reducing knee pain in the majority of people with osteoarthritis, but that the combination of the two supplements provided significant pain relief for people with moderate-to-severe knee osteoarthritis. In this phase of the study, researchers were attempting to determine whether any of the treatments had an effect on reducing the loss of cartilage that occurs with osteoarthritis over time.

Patients were followed for two years and repeated knee X-rays were done. The results revealed that none of the treatments slowed progression of the cartilage loss, although patients with the least severe radiological changes did show a slight trend to some protective effects of the drugs compared to placebo. Therefore, this study fails to support the use of glucosamine and chondroitin either singly or in combination as a treatment for advanced osteoarthritis. The study is limited by relatively small numbers of patients in each treatment group and a relatively short observation period. This study does not exclude the possibility that patients with very early osteoarthritis may benefit from these medications.

Several other studies have shown favorable results for the use of glucosamine and chondroitin sulfate for the treatment of osteoarthritis.

In a multicenter, randomized, placebo-controlled, double-blind, parallel-group study design of 252 outpatients with osteoarthritis of the knee, it was concluded that glucosamine sulfate may be a safe and effective symptomatic Slow Acting Drug for osteoarthritis.

In a randomized, placebo-controlled trial of two hundred two patients with knee osteoarthritis that were randomized to receive oral glucosamine sulfate, 1500 mg once a day, or placebo, it was concluded that long-term (3-year) treatment with glucosamine sulfate retarded the progression of knee osteoarthritis.

Patients with osteoarthritis of the knee were treated with chondroitin sulfate in a randomized, double-blind, placebo-controlled study, performed in two centers. The results of the strongly suggested that chondroitin sulfate acts as a symptomatic slow-acting drug in knee osteoarthritis

A controlled randomized double-blind study versus placebo was conducted in 104 patients with femorotibial osteoarthritis. The results of the study suggests that chondroitin sulfates act as structure modulators as shown by the improvement in the interarticular space visualized on the x-rays of the treated patients.
References:
1. Arthritis Foundation Comment on the Effect of Glucosamine and/or Chondroitin Sulfate on the Progression of Knee Osteoarthritis.
2. Noack W, Fischer M, Förster KK, Rovati LC, Setnikar I. Glucosamine sulfate in osteoarthritis of the knee. Osteoarthritis Cartilage. 1994 Mar;2(1):51-9. PMID: 11548224.
3. Pavelká K, Gatterová J, Olejarová M, Machacek S, Giacovelli G, Rovati LC. Glucosamine sulfate use and delay of progression of knee osteoarthritis: a 3-year, randomized, placebo-controlled, double-blind study. Arch Intern Med. 2002 Oct 14;162(18):2113-23. PMID: 12374520.
4. Bucsi L, Poór G. Efficacy and tolerability of oral chondroitin sulfate as a symptomatic slow-acting drug for osteoarthritis (SYSADOA) in the treatment of knee osteoarthritis. Osteoarthritis Cartilage. 1998 May;6 Suppl A:31-6. PMID: 9743817.
5. Conrozier T. [Anti-arthrosis treatments: efficacy and tolerance of chondroitin sulfates (CS 4&6)]. Presse Med. 1998 Nov 21;27(36):1862-5. PMID: 9856136.