The Effects of Acupuncture on Chronic Knee Pain Due to Osteoarthritis: A Meta-Analysis

Lin, Xianfeng MD; Huang, Kangmao MD; Zhu, Guiqi MD; Huang, Zhaobo MD; Qin, An MD, PhD; Fan, Shunwu MD

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.15.00620
Evidence-Based Orthopaedics
Abstract

Background: Acupuncture reportedly relieves chronic knee pain and improves physical function in patients diagnosed with osteoarthritis, but the duration of these effects is controversial. The aim of this study was to evaluate the temporal effects of acupuncture on chronic knee pain due to knee osteoarthritis by means of a meta-analysis.

Methods: The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched for studies published through March 2015. Ten randomized controlled trials of acupuncture compared with sham acupuncture, usual care, or no intervention for chronic knee pain in patients with clinically diagnosed or radiographically confirmed knee osteoarthritis were included. All of the studies were available in English. Weighted mean differences (WMDs), 95% confidence intervals (CIs), publication bias, and heterogeneity were calculated.

Results: The acupuncture groups showed superior pain improvement (p < 0.001; WMD = −1.24 [95% CI, −1.92 to −0.56]; I2 > 50%) and physical function (p < 0.001; WMD = 4.61 [95% CI, 2.24 to 6.97]; I2 > 50%) in the short term (up to 13 weeks). The acupuncture groups showed superior physical function (p = 0.016; WMD = 2.73 [95% CI, 0.51 to 4.94]; I2 > 50%) but not superior pain improvement (p = 0.199; WMD = −0.55 [95% CI, −1.39 to 0.29]; I2 > 50%) in the long term (up to 26 weeks). Subgroup analysis revealed that the acupuncture groups tended to have better outcomes compared with the controls. Significant publication bias was not detected (p > 0.05), but the heterogeneity of the studies was substantial.

Conclusions: This meta-analysis demonstrates that acupuncture can improve short and long-term physical function, but it appears to provide only short-term pain relief in patients with chronic knee pain due to osteoarthritis.

Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Author Information

1Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, People’s Republic of China

2Department of Orthopaedic Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China

3Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implants, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China

E-mail address for S. Fan: shunwu_fan@126.com

* Xianfeng Lin, MD, Kangmao Huang, MD, and Guiqi Zhu, MD, contributed equally to the writing of this article.

Article Outline

Chronic knee pain is common among people >50 years of age, and it can restrict daily activities such as walking, running, and stair climbing1-3. The United States is estimated to have >20 million affected individuals4. Osteoarthritis is the major cause of knee pain, stiffness, and physical disability5. The main therapeutic goals in the treatment of osteoarthritis are pain relief and functional improvement1.

Both pharmacological and nonpharmacological therapies are important in the management of chronic knee pain6. Pharmacological treatments such as NSAIDs (nonsteroidal anti-inflammatory drugs) and COX (cyclooxygenase)-2 inhibitors can have side effects, such as peptic ulcers and cardiovascular disease, respectively7,8. Exercise, weight loss, herbal or nutritional supplements, and acupuncture have been recommended as nonpharmacological alternatives9-11. Because many patients with osteoarthritis have trouble exercising and losing weight, acupuncture may be a practical option in the treatment of chronic knee pain5,12.

Although not fully understood, the theoretical biochemical basis of acupuncture is considered to include the release of various endogenous substances such as enkephalin, dynorphin, gamma-aminobutyric acid, and β-endorphins, in the spinal cord, midbrain, hypothalamus, and pituitary gland13-15. For each individual patient, the knowledge of traditional Chinese medicine is used to define the proper number of needles, point selection, and acupuncture time (duration and frequency) to achieve the optimal therapeutic effects13,14. Furthermore, the waveform and current frequency of electro-acupuncture can be adjusted during the acupuncture process15,16. A subjective sensation during the acupuncture process, called de qi, is typically characterized by distension, soreness, heaviness, numbness, and/or pressure, and is considered to be a positive effect suggesting the success of acupuncture13,14.

Many researchers have examined the effectiveness and safety of acupuncture for symptoms such as back and neuropathic pain17-20. Whether acupuncture has a definite therapeutic effect on chronic knee pain is controversial. Because of the small number of published studies and their heterogeneity, many systematic reviews have reported inconsistent results1,5,10,21-23. Moreover, the proposed clinical guidelines on the management of knee osteoarthritis have contradictory views regarding acupuncture24-27. Nevertheless, several high-quality randomized controlled trials (RCTs) have recently been published2,4,12,28. The aim of this study was to conduct an updated meta-analysis on the duration of pain relief and function improvement obtained by acupuncture for chronic knee pain due to osteoarthritis.

Back to Top | Article Outline

Materials and Methods

Search Strategy

A systematic review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline (see Appendix)29. We searched the PubMed, Embase, and Cochrane Central Register of Controlled Trials databases through March 2015 using the following terms: (1) “electro-acupuncture,” “percutaneous electrical nerve,” “acupuncture,” or “percutaneous neuromodulation”; combined with (2) “knee,” “gonarthritis,” “osteoarthritis,” “arthritis,” or “pain.” Only studies published in English with the full text available were included. When several publications reported findings for the same patients, the most recent or most complete study was chosen. Chinese studies were not included30.

Back to Top | Article Outline
Inclusion Criteria

Eligible articles were identified according to the flowchart in Figure 1. Studies were included on the basis of the following criteria: (1) adult patients who had had knee pain on most days for >3 months and had clinically diagnosed or radiographically confirmed knee osteoarthritis; (2) treatment by body acupuncture or periosteal stimulation; (3) treatment of a control group with sham acupuncture, usual care, or no intervention; and (4) outcomes of pain and physical function as measured with any instrument.

Back to Top | Article Outline
Definitions

For the meta-analysis, the acupuncture group comprised patients who received body acupuncture or periosteal stimulation, and the control group included those who received sham acupuncture, usual care, or no intervention. “Sham acupuncture” represented nonpenetrating and placebo acupuncture5. “Usual care” represented standard, conservative pharmacological therapy. “No intervention” represented either no routine treatments or alternatives such as education31.

Back to Top | Article Outline
Data Extraction

Two of the authors (X.L. and K.H.) reviewed all titles and abstracts independently to determine eligibility and retrieve articles. Disagreement was resolved by discussion between the 2 authors. If they could not reach an agreement, another author (S.F.) was consulted and a decision was made by a majority vote. The authors are proficient at acupuncture treatment for chronic knee pain.

The following information was extracted according to a fixed protocol: study design, geographical location, demographic information (age and sex), numbers of acupuncture and control participants, interventions, measurement time point(s), and outcomes (Table I). The WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) subscales for pain and physical function were utilized in this study because the WOMAC has been extensively used to assess chronic knee pain32. The duration of the effects of acupuncture was defined by the short-term end point of up to 13 weeks and the long-term end point of up to 26 weeks5. The usual care group of 1 study (Scharf et al.33) was not included as the patients received inconsistent therapy sessions.

Back to Top | Article Outline
Validity Assessment

The Cochrane Collaboration’s tool (Table II) was used to assess bias in each eligible study34. It uses the following assessment criteria to indicate lack of bias: (1) the method of randomization was adequate; (2) the treatment allocation was concealed; (3) the groups were similar in the most important prognostic indicators at baseline; (4) the patients were blinded to the intervention; (5) the caregivers were blinded to the intervention; (6) the outcome assessors were blinded to the intervention; (7) co-interventions were controlled; (8) compliance was acceptable in all groups; (9) the dropout rate was described and acceptable; (10) the timing of assessment in all groups was the same; and (11) intention-to-treat analysis was performed. A score of 1 was awarded for each item if the criterion was completely met; a score of 0.5, 0, or NA was recorded for the item if the criterion was partially met, if it was not met, or if it was unclear whether it was met, respectively. The total score for each study was then calculated; a score of ≥6 indicated a high-quality study5.

Back to Top | Article Outline
Statistical Analysis

Weighted mean differences (WMDs) and corresponding 95% confidence intervals (CIs) were estimated by random-effect meta-analysis. The significance of the pooled WMDs was evaluated by a Z test, and a p value of <0.05 was considered significant. In light of possible sources of heterogeneity, the studies were stratified by interventions, measurement time points, and outcomes, and the analysis was repeated separately for each type of control group. The I2 statistic was used to evaluate heterogeneity, and a fixed or random-effect model was used on the basis of the I2 value. A p value of <0.05 was considered significant for heterogeneity.

Two sensitivity analyses were performed to assess the stability of the pooled effects by omitting 1 of 2 individual studies to determine their influence on the pooled WMDs. One study28 was omitted because of its inadequate acupuncture treatment, and the other12 was omitted because of its large CI. The corresponding remaining studies (the group with adequate acupuncture treatment or the group with relatively small CIs) were then used to recalculate the pooled WMDs. The acupuncture treatment was accepted as adequate if it consisted of at least 6 overall sessions, at least 1 session per week, at least 4 points needled for each painful knee over at least 20 minutes, and manual or electrical stimulation of sufficient intensity to produce more than minimal needle sensation (de qi)1. Begg funnel plots were created to estimate publication bias. The significance of the intercept was evaluated by the Egger test (with p < 0.05 considered significant). RevMan 5.0 (Cochrane Collaboration) and Stata 12.0 (StataCorp) statistical software packages were used for the analyses. All p values were two-sided.

Back to Top | Article Outline

Results

Characteristics of the Studies

Ten RCTs that assessed 2007 subjects were included in the meta-analysis. The sample size ranged from 20 to 697 subjects (Table I). One study included 2 control groups. All of the studies were published in or after 1994. Their validity scores are shown in Table II.

Back to Top | Article Outline
Meta-Analysis Findings

The acupuncture group had significantly better overall pain (p < 0.001; WMD = 0.95 [95% CI, 0.50 to 1.41]; I2 >50%) and physical function (p < 0.001; WMD = 3.68 [95% CI, 2.18 to 5.18]; I2 >50%) scores than the control group. It also showed significantly superior short-term pain (p < 0.001; WMD = 1.24 [95% CI, 0.56 to 1.92]; I2 >50%) (Fig. 2) and physical function (p < 0.001; WMD = 4.61 [95% CI, 2.24 to 6.97]; I2 >50%) scores (Fig. 3). Although the acupuncture group did not have superior long-term pain scores (p = 0.199; WMD = 0.55 [95% CI, 0.29 to 1.39]; I2 >50%) (Fig. 4), significantly better long-term physical function scores (p = 0.016; WMD = 2.73 [95% CI, 0.51 to 4.94]; I2 >50%) were noted (Fig. 5). The sensitivity analyses revealed stable results (Table III); excluding either of the 2 previously mentioned studies12,28 did not alter the pooled WMDs. The heterogeneity of the above results was evident from the I2 values of >50%.

The subgroup analysis suggested that the acupuncture group had superior short and long-term pain scores compared with the sham acupuncture and usual care groups. The acupuncture group also showed a trend toward better physical function scores when compared with the various control groups in both the short and the long term. When compared with usual care and no acupuncture, the analysis had insufficient studies to detect a significant change in both physical function and pain (see Appendix).

Back to Top | Article Outline
Publication Bias

The funnel plots did not reveal obvious asymmetry of pain and physical function scores in either the short or the long term (see Appendix). Consistently, the Egger test suggested a lack of publication bias for both pain (p = 0.88) and physical function (p = 0.69) scores (see Appendix). The funnel plots of the time subgroups are also depicted in the Appendix. According to this analysis, the included studies were relatively comprehensive and yielded statistically reliable results.

Back to Top | Article Outline

Discussion

This meta-analysis demonstrates that acupuncture can result in both short and long-term improvement in function in patients with chronic knee pain due to osteoarthritis, but that the effect of pain relief is not sustained in the long term. Acupuncture tends to have better outcomes than sham acupuncture, usual care, and no intervention. These favorable effects of acupuncture involve complex interactions with the patient, including empathy, intention, care, and attention, that cannot be achieved by medications alone or by no intervention13. In addition, endogenous chemicals released during the acupuncture process, such as enkephalin, dynorphin, and gamma-aminobutyric acid, may have distinct effects for patients with chronic knee pain13-16.

Marked heterogeneity was a limitation of the analysis of the RCTs included in this study. The heterogeneity among studies was evaluated using I2 inconsistency tests, in which values of >50% were considered to indicate high heterogeneity. One possible reason for the observed heterogeneity is that the various acupuncturists performed the treatment without a standardized protocol and according to their individual training and experiences. The variety of control interventions included in this study (sham acupuncture, usual care, and no intervention) may also have led to heterogeneity.

Previous meta-analyses have drawn various conclusions depending on the types of control interventions used for comparison1,5,10. Although Manheimer et al. also showed that the pooled effects of acupuncture were significantly superior to those of sham treatment, the effects were believed to be clinically irrelevant5. In addition, a recent meta-analysis of individual patient data showed that acupuncture was associated with chronic pain relief when compared with sham acupuncture and with no acupuncture35; those results are in agreement with our findings.

The current study revealed some new findings that differ from those of previous reports. First, when acupuncture was compared with all control interventions simultaneously, pain relief was not found to be sustained over time. In contrast, no previous systematic reviews evaluated the effect of pooled control interventions on pain relief.

Second, 2 recent high-quality RCTs have been included here for the first time2,28. They showed no significant effects of acupuncture compared with sham acupuncture or no treatment, but both of the treatments did show pain relief and functional improvement. Although they demonstrated the beneficial effects of acupuncture on pain and physical disability, their results could be explained by a placebo effect or patient expectation. Using multivariable logistic regression, Chen et al. found that active patients were significantly more likely to report positive effects from acupuncture. They believed that a prior positive expectation for an acupuncture effect strongly predicted treatment success28. Hinman et al. used the Zelen design to overcome the limitations of previous studies, with patients having both positive and negative expectations of acupuncture being recruited2. The risk of recruitment bias was minimized by blinding the control participants. They found that laser and needle acupuncture were not superior to sham acupuncture for pain relief or functional improvement. One possible reason for this is that Hinman et al. eliminated the expectation effect, which could expand the effect size difference between acupuncture and sham acupuncture. Furthermore, when compared with no acupuncture, acupuncture resulted in only modest pain relief and functional improvement in the short term. Curiously, no acupuncture control group tended to improve even slightly in the long term. Based on the above data, the findings of the 2 recent RCTs2,28 did not support the effectiveness of acupuncture.

Although the 2 abovementioned recent studies did not support acupuncture treatment, the results of our meta-analysis are mainly positive. No evidence exists that positive attitudes contributed to the previous positive results, although an expectation effect was identified and may have affected the results. Moreover, the patients who held positive attitudes were randomly assigned to the control and treatment groups, so the expectation effect was attenuated.

This meta-analysis has some limitations. First, the included RCTs compared a variety of control interventions; therefore, definite conclusions regarding the various control interventions are not possible. Larger and higher-quality trials are needed to confirm these conclusions. Second, to avoid the expectation effect, future studies should consider the patients’ attitudes regarding acupuncture prior to treatment. Third, the results were based on unadjusted estimates; a more precise analysis should be conducted if individual patient data are available, allowing adjustment for age, sex, ethnicity, and geographical location. Finally, the lack of standardization of acupuncture treatment protocols also limits our findings.

In conclusion, we believe that acupuncture can provide superior pain relief and functional improvement compared with sham acupuncture, usual care, and no intervention in the short term. The effect on pain relief does not appear to be maintained in the long term. Finally, the placebo effect of acupuncture may contribute to its beneficial outcomes.

Back to Top | Article Outline

Appendix Cited Here...

A table showing the PRISMA checklist and figures comparing acupuncture with sham treatment, usual care, and no intervention and showing funnel plots (overall and at each time interval) are available with the online version of this article as a data supplement at jbjs.org.

Investigation performed at the Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, People’s Republic of China

Disclosure: No external sources of funding were used for this study. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article.

Back to Top | Article Outline

References

1. White A, Foster NE, Cummings M, Barlas P. Acupuncture treatment for chronic knee pain: a systematic review. Rheumatology (Oxford). 2007 ;46(3):384–90. Epub 2007 Jan 10.
2. Hinman RS, McCrory P, Pirotta M, Relf I, Forbes A, Crossley KM, Williamson E, Kyriakides M, Novy K, Metcalf BR, Harris A, Reddy P, Conaghan PG, Bennell KL. Acupuncture for chronic knee pain: a randomized clinical trial. JAMA. 2014 ;312(13):1313–22.
3. Collins NJ, Bisset LM, Crossley KM, Vicenzino B. Efficacy of nonsurgical interventions for anterior knee pain: systematic review and meta-analysis of randomized trials. Sports Med. 2012 ;42(1):31–49.
4. Weiner DK, Rudy TE, Morone N, Glick R, Kwoh CK. Efficacy of periosteal stimulation therapy for the treatment of osteoarthritis-associated chronic knee pain: an initial controlled clinical trial. J Am Geriatr Soc. 2007 ;55(10):1541–7.
5. Manheimer E, Linde K, Lao L, Bouter LM, Berman BM. Meta-analysis: acupuncture for osteoarthritis of the knee. Ann Intern Med. 2007 ;146(12):868–77.
6. Weiner DK, Moore CG, Morone NE, Lee ES, Kent Kwoh C. Efficacy of periosteal stimulation for chronic pain associated with advanced knee osteoarthritis: a randomized, controlled clinical trial. Clin Ther. 2013 ;35(11):1703–20.e5. Epub 2013 Nov 1.
7. Gutthann SP, García Rodríguez LA, Raiford DS. Individual nonsteroidal antiinflammatory drugs and other risk factors for upper gastrointestinal bleeding and perforation. Epidemiology. 1997 ;8(1):18–24.
8. Jüni P, Reichenbach S, Egger M. COX 2 inhibitors, traditional NSAIDs, and the heart. BMJ. 2005 ;330(7504):1342–3.
9. Mobasheri A. Intersection of inflammation and herbal medicine in the treatment of osteoarthritis. Curr Rheumatol Rep. 2012 ;14(6):604–16.
10. Cao L, Zhang XL, Gao YS, Jiang Y. Needle acupuncture for osteoarthritis of the knee. A systematic review and updated meta-analysis. Saudi Med J. 2012 ;33(5):526–32.
11. Jordan KM, Arden NK, Doherty M, Bannwarth B, Bijlsma JW, Dieppe P, Gunther K, Hauselmann H, Herrero-Beaumont G, Kaklamanis P, Lohmander S, Leeb B, Lequesne M, Mazieres B, Martin-Mola E, Pavelka K, Pendleton A, Punzi L, Serni U, Swoboda B, Verbruggen G, Zimmerman-Gorska I, Dougados M; Standing Committee for International Clinical Studies Including Therapeutic Trials ESCISIT. EULAR recommendations 2003: an evidence based approach to the management of knee osteoarthritis: report of a task force of the Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCISIT). Ann Rheum Dis. 2003 ;62(12):1145–55.
12. Jubb RW, Tukmachi ES, Jones PW, Dempsey E, Waterhouse L, Brailsford S. A blinded randomised trial of acupuncture (manual and electroacupuncture) compared with a non-penetrating sham for the symptoms of osteoarthritis of the knee. Acupunct Med. 2008 ;26(2):69–78.
13. Stux G, Berman B, Pomeranz B, editors. Basics of acupuncture. 5th ed. Berlin: Springer; 2003.
14. Cho WC-S. Acupuncture and moxibustion as an evidence-based therapy for cancer. Vol. 3. Dordrecht: Springer; 2012.
15. Xia Y, Ding G, Wu G, editors. Current research in acupuncture. Vol. 1. New York: Springer; 2013.
16. Zhang R. World Century compendium to TCM. Vol. 6. Introduction to acupuncture and moxibustion. Hackensack, NJ: World Century; 2013.
17. Melchart D, Weidenhammer W, Streng A, Reitmayr S, Hoppe A, Ernst E, Linde K. Prospective investigation of adverse effects of acupuncture in 97 733 patients. Arch Intern Med. 2004 ;164(1):104–5.
18. MacPherson H, Thomas K, Walters S, Fitter M. The York acupuncture safety study: prospective survey of 34 000 treatments by traditional acupuncturists. BMJ. 2001 ;323(7311):486–7.
19. Cherkin DC, Sherman KJ, Deyo RA, Shekelle PG. A review of the evidence for the effectiveness, safety, and cost of acupuncture, massage therapy, and spinal manipulation for back pain. Ann Intern Med. 2003 ;138(11):898–906.
20. White A, Hayhoe S, Hart A, Ernst E. Adverse events following acupuncture: prospective survey of 32 000 consultations with doctors and physiotherapists. BMJ. 2001 ;323(7311):485–6.
21. Ezzo J, Hadhazy V, Birch S, Lao L, Kaplan G, Hochberg M, Berman B. Acupuncture for osteoarthritis of the knee: a systematic review. Arthritis Rheum. 2001 ;44(4):819–25.
22. Kwon YD, Pittler MH, Ernst E. Acupuncture for peripheral joint osteoarthritis: a systematic review and meta-analysis. Rheumatology (Oxford). 2006 ;45(11):1331–7. Epub 2006 Aug 27.
23. Hopton A, MacPherson H. Acupuncture for chronic pain: is acupuncture more than an effective placebo? A systematic review of pooled data from meta-analyses. Pain Pract. 2010 ;10(2):94–102. Epub 2010 Jan 8.
24. Fernandes L, Hagen KB, Bijlsma JW, Andreassen O, Christensen P, Conaghan PG, Doherty M, Geenen R, Hammond A, Kjeken I, Lohmander LS, Lund H, Mallen CD, Nava T, Oliver S, Pavelka K, Pitsillidou I, da Silva JA, de la Torre J, Zanoli G, Vliet Vlieland TP; European League Against Rheumatism (EULAR). EULAR recommendations for the non-pharmacological core management of hip and knee osteoarthritis. Ann Rheum Dis. 2013 ;72(7):1125–35. Epub 2013 Apr 17.
25. Hochberg MC, Altman RD, April KT, Benkhalti M, Guyatt G, McGowan J, Towheed T, Welch V, Wells G, Tugwell P; American College of Rheumatology. American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee. Arthritis Care Res (Hoboken). 2012 ;64(4):465–74.
26. McAlindon TE, Bannuru RR, Sullivan MC, Arden NK, Berenbaum F, Bierma-Zeinstra SM, Hawker GA, Henrotin Y, Hunter DJ, Kawaguchi H, Kwoh K, Lohmander S, Rannou F, Roos EM, Underwood M. OARSI guidelines for the non-surgical management of knee osteoarthritis. Osteoarthritis Cartilage. 2014 ;22(3):363–88. Epub 2014 Jan 24.
27. Jevsevar DS. Treatment of osteoarthritis of the knee: evidence-based guideline, 2nd edition. J Am Acad Orthop Surg. 2013 ;21(9):571–6.
28. Chen LX, Mao JJ, Fernandes S, Galantino ML, Guo W, Lariccia P, Teal VL, Bowman MA, Schumacher HR, Farrar JT. Integrating acupuncture with exercise-based physical therapy for knee osteoarthritis: a randomized controlled trial. J Clin Rheumatol. 2013 ;19(6):308–16.
29. Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Int J Surg. 2010;8(5):336–41. Epub 2010 Feb 18.
30. Vickers A, Goyal N, Harland R, Rees R. Do certain countries produce only positive results? A systematic review of controlled trials. Control Clin Trials. 1998 ;19(2):159–66.
31. Berman BM, Lao L, Langenberg P, Lee WL, Gilpin AM, Hochberg MC. Effectiveness of acupuncture as adjunctive therapy in osteoarthritis of the knee: a randomized, controlled trial. Ann Intern Med. 2004 ;141(12):901–10.
32. Sun Y, Stürmer T, Günther KP, Brenner H. Reliability and validity of clinical outcome measurements of osteoarthritis of the hip and knee—a review of the literature. Clin Rheumatol. 1997 ;16(2):185–98.
33. Scharf HP, Mansmann U, Streitberger K, Witte S, Krämer J, Maier C, Trampisch HJ, Victor N. Acupuncture and knee osteoarthritis: a three-armed randomized trial. Ann Intern Med. 2006 ;145(1):12–20.
34. van Tulder M, Furlan A, Bombardier C, Bouter L; Editorial Board of the Cochrane Collaboration Back Review Group. Updated method guidelines for systematic reviews in the Cochrane Collaboration Back Review Group. Spine (Phila Pa 1976). 2003 ;28(12):1290–9.
35. Vickers AJ, Linde K. Acupuncture for chronic pain. JAMA. 2014 ;311(9):955–6.
36. Takeda W, Wessel J. Acupuncture for the treatment of pain of osteoarthritic knees. Arthritis Care Res. 1994 ;7(3):118–22.
37. Berman BM, Singh BB, Lao L, Langenberg P, Li H, Hadhazy V, Bareta J, Hochberg M. A randomized trial of acupuncture as an adjunctive therapy in osteoarthritis of the knee. Rheumatology (Oxford). 1999 ;38(4):346–54.
38. Tukmachi E, Jubb R, Dempsey E, Jones P. The effect of acupuncture on the symptoms of knee osteoarthritis—an open randomised controlled study. Acupunct Med. 2004 ;22(1):14–22.
39. Vas J, Méndez C, Perea-Milla E, Vega E, Panadero MD, León JM, Borge MA, Gaspar O, Sánchez-Rodríguez F, Aguilar I, Jurado R. Acupuncture as a complementary therapy to the pharmacological treatment of osteoarthritis of the knee: randomised controlled trial. BMJ. 2004 ;329(7476):1216. Epub 2004 Oct 19.
Copyright 2016 by The Journal of Bone and Joint Surgery, Incorporated