aOrthopedist and Traumatologist; Preceptor of the Knee Surgery Service, Instituto de Ortopedia e Traumatologia de Passo Fundo and Hospital São Vicente de Paulo, Passo Fundo, RS, Brazil
bMédico Orthopedist and Traumatologist; Resident (R4) in the Knee Surgery Service, Instituto de Ortopedia e Traumatologia de Passo Fundo, Passo Fundo, RS, Brazil.
To evaluate the current evidence that support or disprove the use of glucosamine and chondroitin in the treatment of patients with osteoarthritis. We performed a literature review using the databases of Medline, PubMed and the Cochrane Controlled Trial Register and Cochrane Databases Systematic Reviews (Cochrane Library).We considered only studies with high level of evidence.The study included analysis of randomized controlled trials that included at least 100 patients in each intervention group, meta-analyzes and systematic reviews. Seven meta-analysis, one systematic review and five randomized clinical trials fit inclusion criteria of this review. Considering the best evidences until now, the use of glucosamine and chondroitin does not provide clinical relevant benefits to patients with osteoarthritis of the knee or hip (Level I of evidence and grade A of recommendation). Further trials with adequate technology are necessaries to elucidate this question.
Key words: Chondroitin; Glucosamine; Osteoarthritis; Review
Key words: Chondroitin; Glucosamine; Osteoarthritis; Review
INTRODUCTION
Osteoarthrosis, also known as arthrosis or osteoarthritis, is the most frequent form of arthritis and is one of the main causes of limitation and reduction of quality of life among the population over the age of 50 years. The need for financial resources directed towards osteoarthrosis treatment is increasing year by year because of increasing prevalence of osteoarthrosis. These increases are caused mainly by greater life expectancy among the population, which has given rise to higher incidence of degenerative joint diseases.1
It has been estimated that more than 75% of people over the age of 65 years present osteoarthrosis in one or more joints.2 American studies have shown that 12.1% of individuals over the age of 25 years present clinical signs and symptoms of osteoarthrosis and that 6% and 3% of individuals over the age of 30 years present osteoarthrosis symptoms in the knees and hips, respectively.3 Currently, in Brazil, there are no epidemiological studies depicting the prevalence of osteoarthrosis or any data on the amount of public funding used for treating this pathological condition. Even so, with the proportion of elderly people over the age of 60 years at around 9.9% and life expectancy of around another 21.3 years, osteoarthrosis needs to be considered to be a disease of public health interest in Brazil.4
Osteoarthrosis is characterized by degradation of the joint cartilage. This clinical condition is composed of pain, stiffness, joint effusion and joint deformities. Biological, genetic, biochemical, nutritional and mechanical factors contribute towards the etiology of osteoarthrosis.3 , 5
Osteoarthrosis causes destruction of the cartilage with subsequent loss of the joint space. However, it should be considered to be a disease of the entire joint, involving the cartilage, ligaments, synovia and bone. From a supposed genetic component, it is believed that primary osteoarthrosis is triggered by mechanical overloading of the cartilage, which gives rise to a vicious circle of inflammation and degradation of the joint cartilage.The primary agents for this inflammatory pathway are interleukin-1 (IL-1) and tumor necrosis factor (TNF), which induce greater expression of metalloproteinases and nitric oxides (NO), which are the main catabolic agents involved in joint cartilage lesions.5 , 6 , 7
Currently, there is no consensus regarding the ideal treatment for osteoarthrosis. Several treatment methods have been used with the aims of pain relief and improvement of patients' functional abilities. Among these, pharmacological methods, non-pharmacological methods (physiotherapy, occupational therapy, weight loss and exercise), physical agents, alternative therapies (homeopathy, acupuncture and phytotherapeutic medications) and surgical methods can be highlighted.
Non-steroidal anti-inflammatory drugs (NSAIDs) are considered by many authors to be the first-choice medications for pharmacological treatment of osteoarthrosis.8 , 9 Use of NSAIDs has been shown to be effective for pain relief and for improvement of function among patients with osteoarthrosis. However, it needs to be taken into consideration that NSAIDs are medications that treat the symptoms and that they have not been correlated with modification of the natural history of osteoarthrosis. Moreover, the main limitation on chronic use of NSAIDs comes from the potential adverse effects on the gastrointestinal and cardiovascular systems, which are found mainly among elderly patients.10
Recently, new medications have been considered in treatments for osteoarthrosis. Within this new context, glucosamine and chondroitin have emerged as biological alternatives to drug treatment. Even without strong scientific evidence, both of these medications have been seen as substances that modify the natural history of osteoarthrosis.11
It is believed that glucosamine participates as a substrate in synthesizing glycosaminoglycans (GAGs), proteoglycans and hyaluronate in the joint cartilage. It also acts on chondrocytes through stimulating proteoglycan synthesis and inhibiting metalloproteinase synthesis. Use of glucosamine is based on studies done on animal models and in vitro studies that showed that the joint metabolism became normalized during the healing of chondral lesions, along with slight anti-inflammatory action.12 , 13 There are three types of glucosamine available on the market: glucosamine hydrochloride (taken from crab shells), glucosamine sulfate (taken from shrimp shells) and synthetic glucosamine (sulfate). Some studies have shown that glucosamine is more efficient than placebo for improving symptoms and that it can also diminish the speed of progression of joint narrowing in osteoarthrosis.14 - 19
Chondroitin is a glycosaminoglycan (GAG) that is found in several types of tissue, including hyaline cartilage. Recent studies have concluded that chondroitin stimulates synthesis of cartilage, and also acts towards inhibiting IL-1 and metalloproteinases.20 There is also evidence to indicate that chondroitin is better than placebo for alleviating symptoms, but that it is not effective for diminishing the progression of joint narrowing.
In using an association of glucosamine and chondroitin, an initial plasma peak is presented around two hours after ingestion of the medication and a second peak 18 hours afterwards, which indicates that enterohepatic circulation exists. Oral use of glucosamine in a single dose of 1,500 mg produces a plasma concentration of approximately 10 μmol, while use of 500 mg taken three times a day generates a concentration of only 3 μmol. The recommended dose of chondroitin is 1,200 mg per day. In addition, it is believed that the association of glucosamine/chondroitin administered orally is absorbed satisfactorily by means of a saturable mechanism, which is important in clinical practice.21
The potential synergic effects from associating glucosamine and chondroitin are still being studied. One recent study did not find any evidence that associating the medications promoted improvement of the symptoms in comparison with placebo, for treating patients with osteoarthrosis.22
The present review had the aim of evaluating the current evidence supporting or rejecting glucosamine and chondroitin use for treating patients with osteoarthrosis.
MATERIALS AND METHODS
A review of the literature was conducted using the Medline and PubMed databases, the Cochrane Controlled Trial Register and the Cochrane Database of Systematic Reviews (Cochrane Library). The search used the following keywords: glucosamine,chondroitin, osteoarthritis, randomized, controlled and metaanalysis . Only studies defined as presenting high quality of evidence were included (level A, according to the Oxford Centre for Evidence Based Medicine),23 i.e. systematic reviews, metaanalyses and randomized controlled clinical trials (RCTs). The population of interest included patients with knee and/or hip osteoarthrosis who were undergoing nonsurgical treatment for painful osteoarthrosis.
Inclusion criteria for articles
Only studies defined as presenting high quality of evidence were included (level A, according to the Oxford Centre for Evidence Based Medicine):23
- Systematic reviews or meta-analyses on RCTs that evaluated the use of glucosamine/chondroitin in humans with knee and/or hip osteoarthrosis
- Controlled RCTs that compared the use of glucosamine/ chondroitin with placebo or another medication, with a minimum of 24 weeks of follow-up
- Adequately designed studies that included at least 100 patients in each intervention (glucosamine, chondroitin, glucosamine/chondroitin and placebo)
- Studies in which the primary outcome was assessment of pain intensity and the secondary outcome was assessment of the diminution of the joint space by means of radiographs on the knee
RESULTS
Out of the 413 potentially eligible studies investigated in Medline and PubMed (keywords: it AND chondroitin), only 13 studies included the word meta-analysis. Among the 13 meta-analyses evaluated in detail, only eight studies, including one systematic review from the Cochrane Collaboration, fulfilled the inclusion criteria with high quality of evidence presented.15 , 17 , 18 , 24 - 27 Moreover, out of the 58 potentially eligible RCTs, only five fulfilled the inclusion criteria and were thus selected for compiling the present review.19,22,28-31 All the RCTs included presented adequate design and high quality of evidence. In the end, 11 studies fulfilled the inclusion criteria for compiling the systematic review. The abstracts and comments on the studies evaluated are shown inTables 1 and 2.
Table 1 Summary of the systematic reviews and meta-analysis studies evaluated.
| Study (ref#) | Level of evidence | Type of study | Parameters evaluated | Results and conclusions |
|---|---|---|---|---|
| [24] | 1A | Meta-analysis (10 RCTs) N = 3,803 GS/GH, CS vs placebo | Pain (VAS) | GS/ GH and CS did not reduce pain and did not have any impact on narrowing of the joint space. |
| [15] | 1A | Systematic review (25 RCTs) GS vs placebo | Pain/Function Structural effects | The studies without conflicts of interest did not demonstrate any benefits from using GS. |
| [25] | 1A | Meta-analysis 15 studies GH, GS | Pain | Heterogenous studies. Conflicts of interest. Greater effects in studies with conflicts of interest. |
| [31] | 1A | Meta-analysis 6 systematic reviews 1 guideline GS/GH, CS | Pain Joint space Cost effectiveness | GS presented better clinical results. Cost effectiveness not detailed clearly. |
| [26] | 1A | Meta-analysis (6 RCTs) N = 1,502 GS and CS | Joint space | GS and CS delayed the progression of osteoarthrosis after 2-3 years. Slight effects. |
| [27] | 1A | Meta-analysis 20 RCTs N = 3,846 CS vs placebo | Pain | Majority of the studies presented delineation errors. CS did not present any benefits. |
| [18] | 1A | Meta-analysis 15 RCTs GS and CS | Pain/Different parameters evaluated | Only one study presented clarity regarding allocation. Majority of the studies presented conflicts of interest. GS/CS was effective for pain control and improvement of function. |
| [17] | 1A | Meta-analysis GS and CS | Joint space | Functional scores GS was effective with regard to all the parameters evaluated; CS was not shown to be effective in delaying the radiological evolution. Further studies are needed. |
CS, chondroitin sulfate; RCT, randomized clinical trial; GH, glucosamine hydrochloride; GS, glucosamine sulfate; VAS, pain assessment using a visual analogue scale. Cochrane: review published in the Cochrane Library. NSAIDs, non-steroidal anti-inflammatory drugs
Table 2 Summary of the RCTs evaluated.
| Study (ref#) | Level of evidence | Type of study | Parameters evaluated | Results and conclusions |
|---|---|---|---|---|
| [22] | 1A | RCT, controlled, DB N = 1,583 GH, CS, GH+CS, celecoxib, placebo Expected improvement effect | WOMAC with pain Evaluation after 4, 8, 16 and 24 months | GH, CS or GH+CS did not reduce the pain in patients with osteoarthrosis. GH+CS was able to diminish the pain in patients with moderate to severe arthrosis. |
| [19] | 1A | RCT, controlled, DB N = 212 GS 1,500 mg/day/3 years vs placebo Allocation not detailed | Medial joint space WOMAC | GS smaller loss of joint space (p = 0.043). Slight clinical improvement (p = 0.020). Irrelevant clinical difference. Conflicts of interest. |
| [19] | 1A | RCT, controlled, DB N = 202 GS 1,500 mg/day/3 years vs placebo | Medial joint space Womac Lequesne | GS smaller loss of joint space (p = 0.001). Slight clinical improvement 20-25%. Irrelevant clinical difference. Conflicts of interest. |
| [29] | 1A | RCT, controlled, DB N = 186 GS 1,500 mg/day/12 weeks vs placebo | Womac Pain and stiffness Functional score | GS and placebo without difference. Short follow-up. |
| [30] | 1A | RCT, controlled, DB N = 622 CS 800 mg/day/24 weeks vs placebo | Pain Medial joint space | CS promoted improvement of pain and smaller loss of medial joint space. |
CS, chondroitin sulfate; DB, study with double blinding, RCT, randomized clinical trial; GH, glucosamine hydrochloride; GS, glucosamine sulfate; Womac, Western Ontario and McMaster Universities Osteoarthritis Index. Lequesne; scores used for functional evaluation in patients with osteoarthrosis
DISCUSSION
Osteoarthrosis is the commonest form of arthritis and is one of the most frequent causes of morbidity among the population over the age of 50 years. The knee and hip are among the joints most affected and, because these are considered to be load-bearing joints, their involvement certainly gives rise to a high degree of functional limitation of the lower limbs. With increasing life expectancy among the Brazilian population, treatment of degenerative joint diseases should be considered to be a matter of public health interest. In Brazil, there is no precise data regarding the prevalence of osteoarthrosis or the estimated cost of treatment and the social security expenditure resulting from the complications of osteoarthrosis. In the United States, in 2004, US$ 86 billion were allocated to osteoarthritis treatment. The sale of medications and supplements for osteoarthrosis has a turnover of US$ 760 million.32
The clinical treatment for osteoarthrosis is still a matter for debate. Even after many years of research and investment, doubts still exist regarding the efficacy of using glucosamine and chondroitin as medications for modifying the natural history of osteoarthrosis. Most studies published so far lack delineation good enough to draw secure conclusions.
McAlindon et al.18 evaluated 15 RCTs that analyzed the benefit of using glucosamine and chondroitin for treating knee and hip osteoarthrosis.They concluded that glucosamine and chondroitin produced at least moderate effects, but that the quality of the published papers was insufficient and the quantification of the effects presented was generally exaggerated. Only one of the studies included had an adequate description of the randomization methods and only two included intention-to-treat analysis. Another noteworthy point was that most of the studies had been funded by the pharmaceutical industry.The effect of the medication was only less when only the large well-designed trials were taken into consideration.
Lee et al.26 evaluated 1,502 patients in a meta-analysis.The primary outcome of the study was diminished medial knee joint space. It was concluded that glucosamine sulfate and chondroitin sulfate delayed the progression of gonarthrosis through lower loss of joint space after three years of using the medication.The effect found was less with use of chondroitin. It needs to be emphasized that in this study, functional improvement and pain reduction were not evaluated. In a critical interpretation, it needs to be borne in mind that even with a statistically significant difference in favor of using the medication, this may not be related to a clinically relevant outcome if the radiological progression of arthrosis is taken into consideration.
Reichenbach et al.27 evaluated the use of chondroitin sulfate alone in 20 studies with a total of 3,846 patients. They concluded that use of chondroitin alone was not associated with pain reduction and functional improvement. However, a large proportion of the studies presented methodological flaws.
Vlad et al.25 demonstrated that most of the studies on this subject presented conflicts of interest and were too heterogenous to be evaluated together. The positive effects were greater in the studies funded by the pharmaceutical industry. Richy et al.17 showed that glucosamine sulfate and chondroitin sulfate improved function and delayed the progression of arthrosis, but they stated that new studies with appropriate methodology are needed in order to confirm the results.
Towheed et al.15 published an important systematic review in the Cochrane Library in 2009. The review evaluated 25 studies that compared the use of glucosamine with placebo for treating osteoarthrosis and concluded that, up to the time of publication, there was no strong evidence that would justify using glucosamine to treat osteoarthrosis. It included studies that assessed overall pain, function, mobility, reduction of joint space and patient satisfaction with the treatment. In this review, 56% of the studies had some form of relationship with the pharmaceutical industry. The authors emphasized that if the evaluation only included the studies without conflicts of interest with the pharmaceutical industry, there would not be any clinically relevant benefits from using glucosamine to treat osteoarthrosis.
In another systematic review, Black et al.31 reached inconsistent conclusions regarding the clinical improvements among patients using glucosamine sulfate and chondroitin, with only modest effects on pain and function. Their evaluation on joint space reduction produced data that were more consistent, but without clinical relevance. In analyzing glucosamine sulfate alone, significant improvements in pain, function and joint space reduction were observed, but the clinical significance of these data could not be defined with any clarity. Also in this study, the cost effectiveness relationship of the treatment could not be clearly demonstrated.
Recently, Wandel et al.24 published a meta-analysis in the British Medical Journal that included 3,803 patients distributed in 10 large RCTs. All the studies included had at least 100 patients in each intervention (glucosamine sulfate/hydrochloride, chondroitin, glucosamine and chondroitin in association and placebo). Compared with placebo, glucosamine and chondroitin used separately or in association were incapable of diminishing the pain and the radiological progression of the arthrosis.The differences found were small and clinically irrelevant. The authors concluded that neither public healthcare administrators nor health insurance plans should be held responsible for the costs of using such medications. Moreover, these authors also stated that new prescriptions for glucosamine chondroitin should be discouraged in clinical practice.
Among the clinical trials, Clegg et al.22 published a multicenter RCT named GAIT, which compared the use of glucosamine, chondroitin, glucosamine and chondroitin in association, celecoxib and placebo for clinical treatment of patients with knee osteoarthrosis. The clinical trial evaluated 1,583 patients in 13 research centers in the United States. As the primary outcome, the study found that there was a 20% decrease in pain on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and OMERACTOARSI. The general result after 24 weeks of follow-up showed that glucosamine and chondroitin separately or in association did not differ from placebo or celecoxib with regard to overall pain control. However, in analyzing the subgroups, the association between glucosamine and chondroitin was shown to be effective for diminishing pain in patients with moderate to severe gonarthrosis. However, given that the data were not generated for analyses on any particular subgroup, the results extracted from a subgroup should only serve to generate hypotheses for future research. Some authors have questioned the results from this study and have argued that in the USA, glucosamine and chondroitin are substances that are considered to be dietary supplements and do not undergo rigid quality control. Nevertheless, for the GAIT study, the quality control was done by the Food and Drug Administration (FDA).
FINAL REMARKS
We conclude that in the light of the best evidence currently available, use of glucosamine sulfate/hydrochloride and chondroitin do not produce clinically relevant benefits for patients with knee and hip osteoarthrosis (level I evidence and grade A recommendation). Future studies with appropriate methodology are needed in order to elucidate this issue.
REFERENCES
1. Badley E, DesMeules M. Arthritis in Canada: an ongoing challenge. Ottawa: Health Canada, 2003. [ Links ]
2. Felson DT. The epidemiology of osteoarthritis: prevalence and risk factors. In: Kuettner KE, Goldberg VM, editors. Osteoarthritic disorders. Rosemont: American Academy of Orthopedic Surgeons; 1995. [ Links ]
3. Felson DT. An update on the pathogenesis and epidemiology of osteoarthritis. Radiol Clin North Am. 2004;42(1):1-9. [ Links ]
4. Dados extraídos da Rede Interagencial de Informações para a Saúde. Ministério da Saúde do Brasil. Disponível em: http://tabnet.datasus.gov.br/cgi/idb2009/matriz. htm. [ Links ]
5. Martin JA, Buckwalter JA. Roles of articular cartilage aging and chondrocytesenescence in the pathogenesis of osteoarthritis. Iowa Orthop J. 2001;21(1):1-7. [ Links ]
6. Balazs EA. Viscoelastic properties of hyaluronic acid and biological lubrication. Univ Mich Med Cent J. 1968:255-9. [ Links ]
7. Balazs EA. The physical properties of synovial fluid and the special role of hyaluronic acid. In: Helfet A, editor. Disorders of the knee. 2nd ed. Philadelphia: JB Lippincott; 1982. p. 61-74. [ Links ]
8. Towheed TE. Published meta-analyses of pharmacological therapies fot osteoarthritis. Osteoarthritis Cartilage. 2002;10(11):836-7. [ Links ]
9. Towheed TE, Hochberger MC. A systematic review of randomized controlled trial of pharmacological therapy in osteoarthritis of the knee, with an emphasis on trial methodology. Semin Arthritis Rheum. 1997;26(5):755-70. [ Links ]
10. Garner S, Fidan D, Franklin R, Judd M, Shead B, Towheed T, et al. Celecoxib for rheumatoid arthritis. Cochrane Database Syst Rev. 2002;(4):CD003831. [ Links ]
11. Loraza C, Altman R. Chondrotection in osteoarthritis. Bull Rheum Dis. 1997;46(7):5-7. [ Links ]
12. McCarty M. The neglect of glucosamine as treatment for osteoarthritis. A personal perspective. Med Hypotheses. 1994;42(5):323-7. [ Links ]
13. Bassleer C, Rovati L, Franchimont P. Stimulation of proteglycan production by glucosamine sulfate in chondrocite isolated from human osteoarthritic cartilage in vitro. Osteoarthritis Cartilage. 1998;6(6):427-34. [ Links ]
14. Rezende MU, Gomes RG. Tratamento medicamentoso da osteoartrose do joelho. Rev Bras Ortop. 2009;44(1):14-9. [ Links ]
15. Towheed TE, Maxwell L, Anastassiades TP, Shea B, Houpt J, Welch V, et al. Glucosamine therapy for treating osteoarthritis. Cochrane Database Syst Rev. 2009;(2):CD002946. [ Links ]
16. Jimenez S, Dodge G. The effects of glucosamine sulfate on human chondrocyte gene expression. Osteoarthritis Cartilage. 1997;5(SA):72. [ Links ]
17. Richy F, Bruyere O, Ethgen O, Cucherat M, Henrotin Y, Reginster JY. Structural and symptomatic efficacy of glucosamine and chondroitin in knee osteoarthritis: a comprehensive meta-analysis. Arch Intern Med. 2003;163(13):1514-22. [ Links ]
18. McAlindon TE, LaValley MP, Gulín JP, Felson DT. Glucosamine and chondritin for treatment of osteoarthritis: a systematic quality assessment and metaanalysis. JAMA. 2000; 283(11):1469-75. [ Links ]
19. Reginster JY, Deroisy R, Rovati LC, Lee RL, Lejeune E, Bruyere O, et al. Long term effects of glucosamine sulphate on osteoarthritis progression: a ramdomised, placebo-controlled clinical trial. Lancet. 2001;357(9252):251-6. [ Links ]
20. Mathieu P. A new mechanism of actionof chondroitin sulfates ACS4-ACS6 in osteoarthritic cartilage. Press Med. 2002;31(29):1383-5. [ Links ]
21. Toffoletto O, Tavares A, Casarini DE, Redublo BM, Ribeiro AB. Farmacocinética da associação de glucosamine e sulfato de condroitina em humanos sadios do sexo masculino. Acta Ortop Bras. 2005;13(5):235-7. [ Links ]
22. Clegg DO, Reda DJ, Harris CL, Klein MA, O'Dell JR, Hooper MM et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006;354(8):795-808. [ Links ]
23. Oxford Centre for Evidence-Based Medicine. Disponível em: http://www.cebm.net/index.aspx?o=5653. [ Links ]
24. Wandel S, Jüni P, Tendal B, Nüesch E, Villinger PM, Welton NJ, et al. Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network metaanalysis. BMJ. 2010;341:c4675. [ Links ]
25. Vlad SC, LaValley MP, McAlindon TE, Felson DT. Glucosamine for pain in osteoarthritis: why do trial results differ? Arthritis Rheum. 2007; 56(7):2267-77. [ Links ]
26. Lee YH, Woo JH, Choi SJ, Ji JD, Song GG. Effect of glucosamine or chondroitin sulfate on the osteoarthritis progression: a meta-analysis. Rheumatol Int. 2010;30(3):357-63. [ Links ]
27. Reichenbach S, Sterchi R, Scherer M, Trelle S, Bürgi E, Bürgi U, et al. Meta-analysis: chondroitin for osteoarthritis of the knee or hip. Ann Intern Med. 2007;146(8):580-90. [ Links ]
28. 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;162(18):2113-23. [ Links ]
29. McAlindon T, Formica M, LaValley M, Lehmer M, Kabbara K. Effectiveness of glucosamine for symptoms of knee osteoarthritis: results from an internet-based randomized double-blind controlled trial. Am J Med. 2004;117(9):643-9. [ Links ]
30. Kahan A, Uebelhart D, De Vathaire F, Delmas PD, Reginster JY. Long-term effects of chondroitins 4 and 6 sulfate on knee osteoarthritis: the study on osteoarthritis progression prevention, a two-year, randomized, double-blind, placebo-controlled trial. Arthritis Rheum. 2009;60(2):524-33. [ Links ]
31. Black C, Clar C, Henderson R, MacEachern C, McNamee P, Quayyum Z, et al. The clinical effectiveness of glucosamine and chondroitin supplements in slowing or arresting progression of osteoarthritis of the knee: a systematic review and economic evaluation. Health Technol Assess. 2009;13(52):1-148. [ Links ]
32. United States Commitee on Health, Education, Labor and Pensions, Subcommittee on Aging. Centre of Disease Control's role in combating the burden of arthritis. Washington: Department of Health and Human Services; 2004. [ Links ]
⋆Work performed at Instituto de Ortopedia e Traumatologia de Passo Fundo, Passo Fundo, RS, Brazil
Received: August28, , 2012; Accepted: December17, , 2012
Nenhum comentário:
Postar um comentário