Severe knee osteoarthritis: a randomized controlled trial of
acupuncture, physiotherapy (supervised exercise) and
standard
management for patients awaiting knee replacement
- Correspondence to: Dr Lyn Williamson. Rheumatology Department, Great Western Hospital, Swindon. SN36BB. E-mail: lyn.williamson@smnhst.swest.nhs.uk
- Received July 17, 2006.
- Revision received March 22, 2007
- Correspondence to: Dr Lyn Williamson. Rheumatology Department, Great Western Hospital, Swindon. SN36BB. E-mail: lyn.williamson@smnhst.swest.nhs.uk
- Received July 17, 2006.
- Revision received March 22, 2007
Abstract
Objective. To evaluate the effects of standardized western acupuncture and physiotherapy on pain and functional ability in patients with severe osteoarthritic knee pain awaiting knee arthroplasty.
Methods. Three-arm, assessor-blind, randomized controlled trial. Participants: 181 patients awaiting knee arthroplasty. Interventions: acupuncture for 6 weeks; physiotherapy for 6 weeks; standardized advice. Main outcome measures: Oxford Knee Score questionnaire (OKS) (primary); 50 m timed walk, and duration of hospital stay following knee arthroplasty.
Results. There was no baseline difference between groups. At 7 weeks, there was a 10% reduction in OKS in the acupuncture group which was a significant difference between the acupuncture and the control group: Mean (S.D.) acupuncture 36.8 (7.20); physiotherapy 39.2 (8.22); control 40.3 (8.48) (P = 0.0497). These effects were no longer present at 12 weeks. There was a trend (P = 0.0984) towards a shorter in-patient stay of 1 day for the physiotherapy group [mean 6.50 days (S.D. 2.0)] compared with the acupuncture group [mean 7.77 days (S.D. 3.96)].
Conclusions. We have demonstrated that patients with severe knee osteoarthritis can achieve a short-term reduction in OKS when treated with acupuncture. However, we failed to demonstrate any other clinically or statically significant effects between the groups. Both interventions can be delivered effectively in an out-patient group setting at a district general hospital. Further study is needed to evaluate the combined effects of these treatments.
Key words
Introduction
The management of severe knee pain from osteoarthritis (OA), particularly those awaiting knee replacements, is limited. Most patients are elderly, and are vulnerable to the side effects of non-steroidal anti-inflammatory [1, 2] and analgesic medication. Many patients are at a critical stage of life where their mobility and independence are threatened. Any treatment that decreases pain, improves quality of life and improves function whilst waiting for definitive surgery warrants serious evaluation. Patients with marked functional limitation and severe pain prior to knee replacement surgery are likely to have a worse outcome at 1 and 2 yrs post-operatively [3]. It is, therefore, important to optimize pre-operative status. Both acupuncture [4–14], and exercise therapy [15–17] have been shown to be effective in the treatment of osteoarthritic knee pain, but only one study [13] has specifically looked at the most severe subgroup: patients awaiting knee replacement. The effect of acupuncture on post-operative recovery has not been studied. Recent recommendations for the medical management of knee OA include the need to combine non-drug therapies [18], but there are few data directly comparing acupuncture with physiotherapy (supervised exercise). The aim of our study was to compare the effects of acupuncture and physiotherapy on pre-operative pain and function as well as post-operative recovery. We compared their effects against each other, and against current standard management. As many elderly patients are unable to access or afford private physiotherapy or acupuncture, we designed our study to look at the feasibility of providing group treatments in a National Health Service (NHS) out-patient setting.
Methods
Study participants
The study took place between September 2004 and March 2006. We invited 559 patients on the waiting list for knee replacement surgery (total or unicondylar, unilateral or bilateral) to take part in the study. Of the 286 that responded, 181 met the eligibility criteria and consented to take part. The blinded research fellow obtained written consent from all subjects according to the Declaration of Helsinki.
The study inclusion criteria were: patients listed for knee arthroplasty due to OA; patients with unilateral or bilateral knee pain; pain lasting more than 3 months. Patients were excluded if they were: taking anticoagulants; within 2 months after receiving an intra-articular steroid injection; experiencing back pain associated with referred leg pain; suffering from ipsilateral OA of the hip; suffering psoriasis or other skin disease in the region of the knee; suffering from rheumatoid arthritis; and if they had received acupuncture or physiotherapy treatment in the last year.
Randomization
An orthopaedic consultant using computerized block randomization provided 180 sealed opaque envelopes. The computer was asked to block randomize all 180 allocations at once. No stratification was used. The 181st patient was offered a choice of three sealed opaque envelopes each containing one group allocation. The envelopes were opened by the patient in the presence of the study physiotherapist immediately after recruitment to the study. After randomization, 60 patients were allocated to the acupuncture and physiotherapy groups, and 61 patients to the standard management group.
Interventions
The acupuncture cohort attended once a week for 6 weeks. The acupuncture was carried out in a group setting of 6–10 patients by a senior physiotherapist experienced in musculoskeletal acupuncture. The needles (1 inch, 0.25 gauge) were inserted and de chi achieved where possible, and left in situ for 20 min. The acupuncture points used were those most commonly used in previous reported research studies in the field (Fig. 1). Up to three additional needles were used in trigger or traditional points at the physiotherapist's discretion. The physiotherapy group attended in groups of 6–10 patients, hourly, once a week for 6 weeks. They carried out an exercise circuit devised and supervised by the same physiotherapist who provided the acupuncture. The exercises were: static quadriceps contractions; inner range quadriceps contractions; straight leg raises; sit to stands, stair climbing; calf stretches; theraband resisted knee extensions; wobble board balance training; knee flexion/extension sitting on gym ball and freestanding peddle revolutions.
FIG. 1.
Acupuncture points used.
The control group received an exercise and advice leaflet, which had been designed by consensus between the physiotherapy, rheumatology and orthopaedic departments. In this way, we standardized the advice received by the control group to reflect best current practice. At enrolment, patients were told that they were in the ‘home exercise group’.
Blinding
The research fellow carrying out all the assessments was blind to patient treatment allocation until the data analysis was completed.
Outcome measures
A patient completed a questionnaire containing: Oxford Knee Score (OKS) [19] (primary outcome measure); Western Ontario MacMaster (WOMAC) Score [20], 10-cm pain visual analogue scale (VAS); Hospital Anxiety and Depression score (HAD) [21]. Patients also undertook a 50-m timed walk, and were weighed at each assessment. Assessments took place at baseline, week 7, week 12 and 3 months post-operatively. Duration of hospital stay was determined from medical records.
Power calculation
Patients’ numbers were calculated to detect a 5-point difference in improvement in OKS between groups at a 5% significance level with 80% power.
Statistical analysis
Analysis was performed by intention-to-treat with the baseline values used in place of any missing follow-up values. One-way analysis of variance (ANOVA) was used to determine whether the three treatment groups differed. If there were any statistically significant differences or trends indicated by the ANOVA analysis, post hoc tests were carried out between individual groups with a Bonferroni correction applied to adjust the significance level.
Ethics
The Swindon Research Ethics Committee reviewed the study and raised no objections.
Funding
Research and Development Grant, The Great Western Hospital, Swindon.
Results
Baseline
The three groups were comparable at baseline for gender, age and body mass index (BMI) (Table 1).
TABLE 1.
Baseline characteristics of the acupuncture, physiotherapy and control groups
A hundred and sixty-one (89%) patients were assessed at 7 weeks, 120 (66%) patients where assessed at 12 weeks and 69 (38%) patients were assessed at 3 months post-operatively. Length of post-operative stay and the number of out-patient physiotherapy treatments were confirmed from hospital records of 134 (74%) patients. The dropouts at 7 and 12 weeks fell into two main categories: dissatisfaction with treatment allocation (23), and unable to attend for medical or social reasons (20). The high 3 months post-operative dropout rate was due to: the perception of having had too many hospital appointments already (12); inability to contact the patient (26); medical problems delaying or preventing surgery (31); and the patient not having had the intended operation (4). Four patients withdrew from surgery because of symptomatic improvements in their knees, three from the acupuncture group and one from the control group. Three had significant post-operative medical complications, which extended their hospital stay, and were excluded from our post-operative analysis. Three patients had their operations at other hospitals due to waiting list initiatives with no available notes (Fig. 2).
FIG. 2.
Participant flow diagram.
Seven-week assessment
The acupuncture group had a lower OKS than the other two groups at 7 weeks (Table 2): acupuncture group mean (S.D.) score 36.8 (7.2) compared with the physiotherapy mean (S.D.) score of 39.2 (8.2) and control group mean (S.D.) score of 40.3 (8.48). ANOVA P = 0.0497 between the three groups; Bonferroni analysis P = 0.0161 between the acupuncture and control groups; P = 0.0829 between acupuncture and physiotherapy group.
TABLE 2.
Results; means (S.D.)
During the 50-m timed walk, the physiotherapy group had a lower mean walking time (50.3 s, S.D. 17.7) compared with the control group (58.4 s,S.D. 25.2) and the acupuncture group (54.9 s, S.D. 17). These trends in difference did not achieve statistical significance; ANOVA analysis P = 0.0965; Bonferroni analysis P = 0.452 and P = 0.151.
Twelve-week assessment
By 12 weeks, the differences between the groups in terms of OKS (ANOVAP = 0.165) were still present but no longer statistically significant (Table 3). At this stage, the acupuncture (mean 6.58, S.D. 2.29) and physiotherapy groups (mean 6.36, S.D. 2.6) VAS scores were showing trends towards being lower than the control group (mean 7.24, S.D. 2.07). ANOVA analysis P = 0.977; Bonferroni analysis P = 0.96 and P = 0.0414.
TABLE 3.
Changes in means compared with control group (95% confidence intervals)
There were no significant pre-operative changes in HAD and WOMAC between the groups.
Three months post-operative assessments
The physiotherapy group had a shorter post-operative hospital stay (mean 6.5 days, S.D. 2.0) than the acupuncture group (mean 7.77, days S.D. 3.96). Although this did not achieve statistical significance (ANOVA P = 0.0984, Bonferroni P = 0.0728).
Costs
The cost for physiotherapy, based on 10 patients per group, with re-usable gymnasium equipment already available, was £9 per patient. The cost for the acupuncture treatment was £15 per patient. There are no additional costs for the home exercise group. Balanced against this is the potential saving of patients withdrawing from the waiting list, and reduced hospital stays.
Safety
No adverse responses to treatment occurred in any of the groups, beyond occasional minor bruising and bleeding in the acupuncture group, and this was never to the extent to cause any concern or discomfort for the patient.
Discussion
We have demonstrated that patients with severe knee OA can achieve a short-term reduction in OKS when treated with acupuncture, in an NHS out-patient group setting. However, we failed to demonstrate any other clinically or statistically significant effects between the groups.
We know of no other studies that have compared acupuncture with physiotherapy directly, or looked at post-operative function. This study has a number of strengths including the uniformity of the study population, and use of the same practitioner in the same environment for both treatment groups to minimize sources of variation. We used reproducible therapies and primary outcome measures, which are directly relevant to current clinical practice. The OKS [19] is the most widely used pre-operative scoring system. It is increasingly being used to guide clinical decisions about referral from general practice and suitability for operation.
Our study probably underestimates the full potential of both acupuncture and physiotherapy. Funding constraints meant that we only offered a 6-week course of treatment, which was the minimum treatment time needed to document any meaningful acupuncture improvement, based on clinical experience and current practice. Most other acupuncture studies use 8 or 10 treatment sessions [14]. We did not expect this improvement to be sustained after the treatment had stopped, given the severity of the underlying arthritis. The acupuncture was also limited to standardized western acupuncture, rather than individual treatment plans. The group setting was used to reproduce the class environment of the exercise class and also to minimize treatment cost. These factors may also have limited the acupuncture effect. As waiting list patients only require temporary pain relief, the short–lived effects of these treatments are entirely appropriate in this study.
The physiotherapy group format is already well established for patients with OA of the knee. In this situation, the element of camaraderie and competition can improve outcome. The improvement in walking time although non-statically significant for the physiotherapy group may well have reflected improved quadriceps and physical function and contributed to the shorter post-operative in-patient stay for this group [3]. However, the 6-week treatment period may not have been enough to build up the full effects of the physiotherapy. The improvement diminished after stopping the exercise classes possibly due to decreased motivation once no longer seeing the physiotherapist.
We included a non-treatment group in the study design to control for any placebo effect in the other two treatment groups. Although our non-treatment group did not act as a true control group, it allowed us to standardize our control group more effectively than in previous studies. We had raised the quality of the baseline advice given to all patients by producing a new exercise leaflet, which they used, and found helpful [22]. At enrolment, the control patients were told that they were the ‘home exercise group’. They subsequently underwent the same assessments and measurements as the treatment group patients and were therefore more motivated than standard pre-operative patients to perform their exercises. Some patients in this group also felt competitive towards the other two treatment groups. Those who exercised regularly did so until the time of operation. This group had a shorter post-operative hospital stay than the acupuncture group and this may be a demonstration of the active versus passive treatment effects. The acupuncture group received a passive treatment, which was then withdrawn. The exercise groups (home and hospital) had active treatment, which they were encouraged to carry out at home throughout the pre-operative period.
The length of in-patient stay is an important outcome measure that can be influenced by many confounding factors. We could interpret our findings as showing that either the acupuncture treatment actually increased the length of stay in comparison with the other two groups, or the two exercise treatment groups decreased the length of hospital stay compared with the acupuncture treatment group. If the two exercise groups did actually reduce the length of stay by 1 day then this is clinically and financially significant and warrants further study.
Our study could be interpreted as showing negative results, with the improvement in OKS in the acupuncture group being one positive result out of a series of non-significant results. However, as the OKS was the primary outcome measure, and showed changes similar to those we hypothesized in our power calculation, we feel that we demonstrated that there is some potential for improvements perhaps with longer or more intensive treatment courses. The changes we demonstrated are small when compared with other acupuncture or physiotherapy and knee OA studies [6, 7, 9, 16]. However, these studies all used longer treatment courses in less disabled patients.
The financial costs of these treatments when delivered in this standardized, group setting are small. A few patients may improve enough to be withdrawn from surgery. In our cohort, three out of 60 in the acupuncture group, one in the control group and none in the physiotherapy group withdrew from surgery. Any further study needs to include formal economic assessment to include cost savings from surgery withdrawal, reduced in-patient stay, pre-operative analgesia and post-operative resources used.
We have demonstrated that acupuncture for knee OA can be delivered in an effective way that is affordable to the public purse, as well as accessible and acceptable to elderly patients.
We have provided a working NHS model, which we can refine by studying the combined effects of both treatments, and continuing therapy until arthroplasty. This is now economically feasible given the shortened waiting times. This treatment could potentially improve quality of life of knee arthroplasty waiting list patients. It is potentially cost-effective in terms of patients reduced need for surgery and shortened in-patient hospital stay.
Conclusions
We have demonstrated that patients with severe knee OA can achieve a short-term reduction in OKS when treated with acupuncture, in an NHS out-patient group setting. However, we failed to demonstrate any other clinically or statistically significant effects between the groups. Both interventions can be delivered effectively in an out-patient group setting at a district general hospital. Further study is needed to evaluate the combined effects of these treatments.
Acknowledgements
The authors would like to thank Mr S. Deo, Orthopaedic Consultant, The Great Western Hospital, Swindon, and the Orthopaedic Department, the Physiotherapy Department and the Research and Development Department, The Great Western Hospital, Swindon.
The authors have declared no conflicts of interest.
- © 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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