Chronic knee pain is a common and disabling condition, particularly in people over 50 years of age
[1, 2]. Knee joint osteoarthritis (OA) is a major cause of knee pain and results in loss of functional independence, psychological impairment and a reduction in the overall quality-of-life of affected individuals. In addition to the personal burden of knee OA, there are substantial direct and indirect health care costs particularly in terms of employment status, productivity and joint replacement surgery, making knee OA a substantial public health problem.
Management of knee OA is primarily focused on treating the pain and disability associated with the condition, with non-pharmacological therapies considered the cornerstone of treatment
. Acupuncture is a popular treatment for pain and dysfunction associated with musculoskeletal conditions. A study of 350 rheumatology patients in the United Kingdom revealed that 61% of those with OA had used acupuncture
. In clinical practice, a range of health professionals administer or refer patients for acupuncture. In Australia, acupuncture by medical practitioners has been established for 40 years and has gained widespread patient acceptance in the community. We have found that over 80% of surveyed general medical practitioners referred patients for acupuncture
 and that they generally consider acupuncture to be highly effective and safe
. Amongst all complementary and alternative medicine modalities, acupuncture is associated with the highest average annualised expenditure
. Thus research to determine its efficacy and cost-effectiveness is warranted.
Acupuncture traditionally involves the insertion of fine needles into specific points of the body. According to the ancient philosophy of traditional Chinese acupuncture, energy circulates in 12’meridians’ located throughout the body. Pain or ill health will result if the meridian energy circulation is blocked. Stimulating the appropriate combination of meridian acupuncture points in the body can restore energy circulation, health, and balance
. From a Western medicine perspective, acupuncture is a technique of peripheral sensory stimulation (through activation of peripheral A-delta and C fibres) applied at acupuncture points and/or trigger points that can activate central nervous system pain pathways, release specific pain relieving substances as well as reduce muscle and sympathetic nervous system tonicity
In recent years there has been a substantial increase in the number of randomised controlled trials (RCTs) investigating the efficacy of needle acupuncture for chronic knee pain. A recent meta-analysis concluded that while placebo-controlled trials show statistically significant benefits for pain, the benefits are small and unlikely to be clinically relevant
. Waiting list-controlled trials however suggest statistically significant and clinically relevant benefits, which may be due to expectation or placebo effects. Accordingly, well-designed rigorous RCTs are needed that control for both placebo and expectation effects in order to evaluate the efficacy of acupuncture for chronic knee pain.
Although acupuncture has been traditionally administered with needles, the use of laser acupuncture has increased because of its pain-free nature and minimal adverse effects
. Laser acupuncture involves the application of low-level laser, which is a form of electromagnetic radiation in the visible or infrared region of the light spectrum. These laser devices are manufactured with such low energy densities that photo-chemical changes are elicited without photo-thermal effects. Within these ranges, various energy levels and wavelengths can be used depending on the tissue penetration required. In laser acupuncture, the beam of light generated is applied to the skin at acupuncture points and/or trigger points, similar to the application of needles.
Laser acupuncture effects are thought to alter peripheral afferent nerve stimulation, modulating spinal cord afferent input on second order neurons and enhancing peripheral endogenous opioid analgesia
 as well as acting via centrally mediated mechanisms. Laser also has effects at the local cellular and tissue level
 with evidence of modulation of inflammatory processes
 varying according to laser dosage
In contrast to needle acupuncture, the efficacy of laser acupuncture has been less well studied in the management of chronic knee pain. In general, RCTs have used small sample sizes and variable laser dosages in terms of wavelength, total energy, application sites and number of treatments. In a meta-analysis of eight trials published up until 2006 investigating the short-term efficacy (within 4 weeks) of laser therapy for knee OA, statistically and potentially clinically significant pain-relieving benefits over placebo were found
. The effect was greater when only trials evaluating an optimal dosage and administration were included. Since this meta-analysis, two other small studies have been published providing further support for the use of laser acupuncture in chronic knee pain
It is not clear whether differences in efficacy exist between laser and needle acupuncture given that there are no direct head-to-head comparisons of needle and laser acupuncture for chronic knee pain., However, in a systematic review, laser but not needle acupuncture offered statistically and clinically significant short-term pain relief over placebo
. Similarly, a meta-analysis found that treatment with laser acupuncture had better pain outcomes in the medium-term, although not short-term, than treatment with needle acupuncture in people with non-specific neck pain
. These studies suggest that laser acupuncture may be at least as effective, if not more effective, than needle acupuncture.
It is apparent that there is a need for further evaluation of acupuncture in the management of chronic knee pain. This is highlighted by discrepancies in recommendations by clinical guidelines – the Osteoarthritis Research Society International currently recommend acupuncture
, the United Kingdom NICE clinical guidelines could not give a firm recommendation due to insufficient evidence
 and the American College of Rheumatology
 conditionally recommend acupuncture but only for patients with moderate to severe pain who are candidates for joint replacement but are unwilling/unable to have surgery. Furthermore, there is limited information about the maintenance of acupuncture effects with no studies reporting a follow-up longer than three months.
In designing appropriate clinical trials, a methodological concern in acupuncture trials has been the difficulty in having a true placebo control group given pre-existing participant expectations, particularly where the treatment itself is multidimensional involving therapist-patient interaction as well as an intervention
. A meta-analysis has confirmed a significant placebo effect for the treatment of pain in knee OA that varies in size depending on the intervention
. For acupuncture, the placebo effect size (mean 0.71 (95% confidence interval 0.53, 0.90)) was higher than the overall effect size for all placebo treatments (0.51 (0.46, 0.55)). As with many treatments, higher patient expectation has been shown to be associated with greater improvements following acupuncture treatment. A pooled analysis of four clinical trials of acupuncture found that after completion of treatment, the odds ratio for response between patients considering acupuncture an effective or highly effective therapy and patients who were more sceptical was 1.67 (95% confidence interval 1.20-2.32)
. The use of “sham needle” acupuncture as a placebo control, whereby needling is performed superficially or at non-acupuncture sites, is controversial given that such a procedure may still produce biological responses and hence may not be truly placebo. Blinding of clinicians administering needle acupuncture is also problematic. Such methodological difficulties can be overcome in trials of laser acupuncture as it is possible to successfully blind both participants and clinicians by using specially designed laser machines
First described by Zelen in the New England Journal of Medicine in 1979
, Zelen design trials are a means of reducing bias by minimizing participant expectations in a treatment trial where the knowledge of the intervention itself may influence the study outcome (Hawthorne effect) in the control group. This is done by enrolling participants into an observational study but covertly randomising participants following their recruitment into a treatment trial (post-randomised consent). The control group remains unaware of the treatment being evaluated
. Such a design has been used successfully in a study comparing a physiotherapy treatment of exercise and knee taping to standard non-physiotherapy treatment in people with predominant patellofemoral OA
. A potential disadvantage of the Zelen design can be a higher crossover rate than a usual RCT which may dilute treatment effects in an intention-to-treat analysis. However, a review of 58 RCTs using the Zelen design found that while most trials (n = 41) experienced some crossover from one group to the other (median crossover = 8.9%, interquartile range 2.6% to 15%) the rate was usually within acceptable limits
Thus, we are currently conducting a Zelen design RCT to investigate the efficacy of needle and laser acupuncture administered by experienced medical acupuncturists in people with chronic knee pain and to evaluate maintenance of effects over the longer term. We will also evaluate the cost-effectiveness of needle and laser acupuncture, as well as explore whether psychosocial measures are associated with changes in pain, physical function and health-related quality of life following acupuncture treatment. This paper describes the protocol for this ongoing trial.
The primary hypotheses are that:
Laser acupuncture will result in significantly greater improvements in pain (as measured overall via numerical rating scale (NRS)) and physical function (as measured via Western Ontario and McMaster (WOMAC) Universities Osteoarthritis Index) than sham laser acupuncture at 12 weeks.
Laser and needle acupuncture will result in significantly greater improvements in pain (as measured overall via NRS and physical function (as measured via WOMAC) than no treatment at 12 weeks.
Laser acupuncture will result in significantly greater improvements in pain (as measured overall via NRS) and physical function (as measured via WOMAC) than needle acupuncture at 12 weeks.
The secondary hypotheses are that:
Sham laser acupuncture will result in significantly greater improvements in pain (as measured overall via NRS) and physical function (as measured via WOMAC) than no treatment at 12 weeks.
Laser, sham laser and needle acupuncture will result in significantly greater improvements in pain (as measured overall via NRS) and physical function (as measured via WOMAC) than no treatment at 12 months, while laser acupuncture will result in significantly greater improvements than needle acupuncture.
Laser, sham laser and needle acupuncture will result in significantly greater improvements in pain (as measured on standing and walking via NRS and by WOMAC), physical function (as measured via NRS) and health-related quality of life than no treatment at 12 weeks and 12 months.
Laser acupuncture will result in significantly greater improvements in pain (as measured on standing and walking via NRS and by WOMAC), physical function (as measured via NRS) and health-related quality of life than needle acupuncture at 12 weeks and 12 months.
A greater proportion of people receiving laser, sham laser and needle acupuncture will report global overall improvements compared to no treatment at 12 weeks and 12 months.
A greater proportion of people receiving laser acupuncture will report global overall improvements compared to needle acupuncture at 12 weeks and 12 months.