Efficacy of Bowen therapy in postoperative pain management – a single blinded (randomized) controlled trial
Dr. Günter Hipmair
Department of Orthopaedic Surgery, Linz General Hospital AKH Linz Krankenhausstrasse 9 A-4020 Linz, Austria
Tel.: 0043 (0)732-7806-1710
Fax: 0043 (0)732-7806-1077
Authors: Hipmair G.¹, Ganser D.², Böhler N.¹, Schimetta W.³, Pölz W.³
1 Department of Orthopaedic Surgery, Linz General Hospital, Austria
2 Emergency Department, Linz General Hospital, Austria
3 Applied Systems Research and Statistics Johannes Kepler University; Linz, Austria
Several case reports point to a possible reduction of postoperative pain with the use of Bowen therapy (Bowtech®). The aim of this study was to evaluate the effect of Bowen therapy in patients after total knee replacement.
Patients and methods.
We enrolled 91 patients in our study. The population was randomly split into three groups: in addition to standard postoperative pain therapy, group A underwent Bowen therapy, group B received a manual sham therapy, and group C constituted the control group without additional treatment. Postoperative pain was assessed with the visual analogue scale (VAS).
VAS pain score averaged from postoperative days 1 until 10 was considered the primary endpoint.
The groups were similar regarding to age, sex and side of operation. During the time of observation we could not detect a statistically significant difference in average pain score between the three groups (median VAS in groups A, B and C: 1.37 [0.76 – 2.07], 1.45 [0.87 – 1.80], and 1.75 [0.79 – 2.51], respectively, p-value: 0.663). We, however, observed a trend of lower VAS scores in the Bowen group within the first two days of treatment.(p-values <0.001 and <0.008, respectively).
Conclusion. The study results indicate that in the early period after knee replacement Bowen therapy may be an effective additional treatment tool for pain reduction.
Keywords: Bowen therapy, knee replacement, postoperative pain, visual analogue scale, complementary medicine
Over the past few years, postoperative pain management after orthopaedic procedures has become more and more standardized.
Several orthopaedic associations issued postoperative recommendations (1) and guidelines (2) based on the WHO analgesic guidelines. Parallel to allopathic medicine, holistic medical therapeutic concepts are emerging at different pace in different regions.
In the German speaking countries, the Bowen ® therapy has become more and more popular over the last few years. In Germany (currently around 400 registered members calling themselves “practitioners”) and Austria (approximately 600 accredited instructors) the number of “practitioners” is on the rise.
Conversely, there is still a lack of scientific evidence of complementary and alternative medical techniques in the majority of cases. Due to the activity of many Bowen practitioners in proximity to our working area (Linz, Upper Austria, Europe), this therapy had attracted our attention. Although there does not exist an explanation for the exact mode of action yet, several theories have been proposed (3,4). An in depth description of the Bowen technique is provided on the Bowen homepage (5):
“Named after its developer, the Australian Tom Ambrose Bowen, the Bowen® technique is a dynamic system of holistic muscle and connective tissue therapy. It has been successfully applied for more than 40 years in the field of general health promotion and various medical conditions. What is amazing about the Bowen technique is its simplicity and efficiency. It is subtle, non invasive and its positive effects begin to show in most clients often already after a few treatments. Gentle movements of the tissues stimulate the flow of energy and amplify the body’s own impulses and resources of self regulation and selfhealing capacity.”
Due to the positive reports (6) from Australia, claiming a remarkable effect in reducing postoperative pain conditions, we decided to conduct a scientific trial.
Aim of our study was to further evaluate the effect of Bowen therapy in postoperative pain conditions in patients after knee replacement surgery in the early postoperative phase (day 0 – 12 after operation). The primary objective was to compare the pain intensity averaged between postoperative day 1 and 12.
Material and Method
The study was designed as a monocenter, randomized, controlled and single blinded interventional study (three arm parallel group design, blinding of study participants in groups A and B, blinding of the observer regarding pain medication)
at the Department of Orthopaedic Surgery at the Linz General Hospital, Austria, Europe.
Inclusion criteria were the diagnosis of gonarthrosis with planned total knee replacement prostheses in epidural anesthesia, as well as the ability to keep a pain diary. Pain intensity was measured with the visual analogue scale (VAS: 0 points = no pain, 10 points = maximum pain).
Patients with dementia, patients who had received Bowen therapy preoperatively, patients with prior endoprosthetic knee surgery in their medical history, uncontrolled diabetes mellitus, terminal cancer, long-term immobilisation, active ulcers of the upper gastrointestinal tract, recent diagnoses of severe/instable cardiovascular and/or pulmonary diseases as well as patients already enrolled in other scientific studies were not eligible for inclusion.
The study was approved by the local ethics committee. All patients gave their informed consent on the day before the operation.
Patients were randomly split into three groups to undergo the following therapeutic regimen on top of standard analgesic therapy: Patients in group A received Bowen therapy, whereas participants in group B were treated with a manual sham intervention mimicking Bowen therapy, and patients in group C were managed with standard analgesic therapy only. Enrolled patients were randomly assigned in a first step to either the treatment groups (A or B) or to the control group (C). The physician who administered the Bowen therapy then decided in a second step which of the individuals allocated to the treatment groups (A or B) actually received Bowen therapy (A) or sham treatment (B). The final treatment group allocation (A or B) was concealed to the study’s main investigator until statistical evaluation.
Bowen treatments were carried out according to Bowen therapy standards. The treatment sequences consisted of a certain set of Bowen moves particularly developed for ailments of the knee („Knee procedure“)(7).
The first moves were the so called “basic moves“ Lower Back 1 and 2 (equivalent to left and right). Subsequently, the actual knee treatment according to the Bowen regimen was performed (moves 1,2,3,4,5,6,7,17,18-21 and 22 (7).
The Bowen treatment group received the first treatment on the second postoperative day after removal of redon drains at the time of the first routine change of the postoperative dressing. The second and last Bowen treatment followed within the final days of their stay in hospital (usually postoperative day 7 to 10).
Sham treatment did not follow the Bowtech® protocol but consitsted of soft touches mimicking the Bowen technique (sham treatments) in proximity to the usual area of treatment. The scheme of the treatment (real or sham) was set up as shown in figure 1.
All patients were advised to keep a pain diary during their stay and to record the VAS score three times daily (at 7:00 a.m., 2:00 p.m. and 9:00 p.m.) The patients were instructed extensively on admission by a skilled physician, as to how to use this diary. Additionally, nurses and doctors were available for further support in these matters any time.
The postoperative standard pain management was in accordance with established hospital guidelines and was unaffected by participation in any of the study groups.
Pain therapy consisted of patient-controlled epidural anaesthesia (PCEA) with a mixture of 400 milliliters (ml) sodiumchloride with 100 ml ropivacaine (= 0.2% ropivacaine solution) + 20 ml fentanyl (500 microgramm(µg)/10 ml ampules) delivering continuously an amount of 4 ml with the possibility for patient-triggered optional boluses (4 ml per bolus).
The amount of boluses per patient was limited to one bolus per hour.
Additionally,75 mg diclofenac intravenously and on demand (again, patient-triggered), paracetamol 1000 mg intravenously or metamizole 500-1000 mg orally were available as well as piritramid in single doses of 7.5 to 15 mg intravenously in case of pain exacerbations.
After removal of the epidural catheter at noon on the second postoperative day, diclofenac 100 mg twice daily was routinely administered until discharge.
Regardless of study group allocation, all patients were set on physiotherapy postoperatively.
Figure 1: Scheme of treatments.
Day -2 = Operation
Day -1 = 1st postoperative day
Day 0 = 2nd postoperative day: VAS at 7:00 a.m., 7:30 – 7:45 a.m. removal of wound drains(WD), 9:00 a.m. – 11.00 a.m. Bowen therapy / sham-treatment (B/S)
Days 1 – 10 = 3rd to 12th postoperative day: VAS daily at 7:00 a.m., 2:00 p.m. and 9:00 p.m.
On day 7, 8, 9 or 10 second Bowen therapy/sham-treatment (B/S)
In this study, an intention-to–treat as well as a per-protocol analysis were performed, of which the latter was considered to be more relevant to assess the efficacy of different procedures.
Missing data were not replaced.
A sample size calculation with pilot data for group C (3rd to 12th postoperative day: øVAS=1.9, SD= 1,12) showed that 30 eligible participants had to be enrolled in each study group to allow the detection of a mean difference of 0.9 points in the VAS score between groups with a statistical power of 80% in the per-protocol analysis (α=5%, ß=20%, parameter-free testing procedure).
For group-comparison of metrical parameters ( for example main outcome parameters) the Kruskal-Wallis Analysis of Variance by ranks (α =5%) was applied with consecutive multiple comparisons according to Nemenyi.
Group comparisons with nominally scaled data were carried out via the Chi Square Test of Homogeneity (α= 5%).
Subsequent covariance analyses of the primary endpoint accounting for the VAS score on the morning of surgery and on the morning of the first and second postoperative day were performed by means of ANCOVA and RANCOVA (α=5%).
As there was no adjustment of the alpha error level for multiple testing, only the analysis of the main parameter can be considered confirmatory, the p-values of all other statistical comparisons have purely descriptive character and were provided for hypothesis generating only. However, evidence of p-levels <0.001 would not have surmounted a probability of error of 5% in case of possible adjustment of the alpha error level according to Bonferroni.
As far as not otherwise specified, data are given as median and interquartile range (in parenthesis).
For the evaluation of sample size, software “N” (IDV Gauting, Germany, version XY) was used, all other calculations were performed with PASW Statistics 18 (SPSS Inc., IBM Company Headquarters, 233 S.Wacker Drive, Chicago, Illinois 6060). A two-tailed p-value below 0.05 was considered statistically significant for all tests.
From May 2008 until November 2009, 96 patients were included in the study, 32 patients per study arm. Five patients were excluded from final analysis due to study protocol violations or missing compliance (one patient of group A, four patients of group B and none of group C). Thus, 91 patients were finally included in the per protocol analysis (31 patients in the treatment group, 28 patients in the sham-treatment group and 32 patients in the control group).
Patients were not different according to baselines variables (sex, age, operation site), except for the preoperative VAS score which was significantly higher in the Bowen group (table 1).
Group A (Bowen)
Group B (Sham Therapy)
Group C (Control Group)
p – value
n = 31
n = 28
n = 32
Age (Years), median [IQR]
71 [63; 74]
70 [68; 75]
70 [65; 76]
Side of operation
PreoperativeVAS 7:00 a.m., median [IQR]
Table 1: Baseline characteristics. IQR = interquartile range.
The first intervention was performed in all patients in group A and B on the second postoperative day after removal of redon drains, in accordance with the study protocol. The second procedure followed on the7 th to 10th postoperative day in 46 patients corresponding to the protocol. Six patients received treatment one day, one patient two days prior to the assigned date. Four patients had been discharged from hospital prematurely before the second treatment. Three of them belonged to the Bowen group and one patient to the sham group.
Figure 2 shows the time course of the VAS score of the different study groups from the day of surgery until postoperative day 12. We could not detect a statistically significant difference between the averaged VAS scores of the different study groups (table 2). However, we identified a trend towards lower VAS scores in the Bowen treatment group on postoperative day 0 to three (statistically significant, see table 3 and 4). This effect was blunted during the following days, and in our setting the second Bowen intervention was unable to show a statistically significant positive benefit again. However, as these sub-analyses were not prespecified and our study was not powered to detect such differences, further randomized trials are needed to confirm or reject this hypothesis.
p – value
n = 31
n = 28
n = 32
3-12 postoperative day
Table 2: Averaged median VAS scores on postoperative days 3-12. IQR = interquartile range.
VAS – score
n = 31
n = 28
n = 32
Day 0 7:00 a.m., median [IQR]
Day 0 2:00 p.m., median [IQR]
Day 0 9:00 p.m., median [IQR]
Day 1 7:00 a.m., median [IQR]
Day 1 2:00 p.m., median [IQR]
Day 1 9:00 p.m., median [IQR]
Day 2 7:00 a.m.. median [IQR]
Day 2 2:00 p.m.. median [IQR]
Day 2 9:00 p.m.. median [IQR]
Table 3: Individual VAS scores at different postoperative days and points of time. IQR = interquartile range.
VAS-score 2nd postop. day 9:00 p.m.
VAS-score 3rd postop. day 2:00 p.m.
VAS-score 3rd postop. day 9:00 p.m.
Table 4: Between group differences of VAS scores at different points of time on postoperative days two and three. Statistically significant results are in bold typ.
Figure 2: Time course of the VAS score of the different study groups from the day of surgery until postoperative day 12 (at 9.00 p.m. on each day).
One of the main problems of many concepts in complementary medicine is a missing scientific basis and a lacking evidence of efficacy. Even if a method or treatment strategy is used extensively, it does not prove or even implicate an actual healing mechanism.
Prospective, blinded randomised controlled trials are therefore needed in order to provide such a proof of clinical efficacy.
In our study, we could not detect an additive beneficial long-term effect in the group treated with Bowen therapy on top of standard analgesic regimen after total knee replacement. However, we noticed a distinctive pain reduction with Bowen therapy immediately after the first treatment within the first three days after surgery.
In our study, the second treatment was scheduled approximately a week after the initial Bowen session. This time interval was in accordance with the recommendations of the founder of Bowen therapy. The gap of five to ten days between treatments should give the body the chance to process the information it has been given by Bowen therapy. This regimen is applied by many practitioners and is in accordance with current treatment practice (3). After the second Bowen treatment we could not show such a beneficial effect anymore. Yet, it has to be mentioned that with VAS levels of around one (minimal pain) from postoperative day nine onward, the measured pain levels were probably too low to allow a detection of a statistically significant difference in this setting. Moreover, if the second treatment would have been scheduled earlier during the postoperative course, it might have revealed a positive effect, too. More clinical trials with a larger number of participants and thus more statistical power are needed to further elucidate this topic.
In clinical trials evaluating manual procedures and therapies, blinding of the practitioner remains challenging. One of the limitations of our study was that the practioner administering the Bowen or sham therapy was aware of patients’group allocations. This may have introduced a performance bias due to the personal opinion and inclination of the practitioner towards Bowen therapy. This inclination might have unconsciously be conferred on the patient. Furthermore, patients might have identified sham therapy because it was administered with less devotion by a physician experienced in Bowen therapy. In our opinion these problems cannot be overcome when testing a manual procedure because the physician responsible for application of Bowen and sham treatment is unblinded to the kind of treatment as a matter of fact. Application of the sham treatment by another physician might have in turn introduced another kind of performance bias. Reporting of the VAS score by the patients is prone to bias, too (detection bias). A “relative frustration” in the standard therapy/sham treatment groups with a less euphorical self-evaluation is conceivable (reduced placebo effect in the sham treatment group as compared to the Bowen therapy group). This might have contributed to the finding of a short term effect of Bowen therapy treatment within the first postoperative days. Despite its flaws, the VAS score seemed adequate to evaluate quality of life after surgery.
It has to be stressed, however, that a performance bias or detection bias (VAS score) should have led to a dismission of the null hypothesis and thus to a statistically significant effect of Bowen therapy over standard therapy and sham treatment which was not the case in our trial. It remains a fact, however, that in the patient group with the highest initial VAS level (see figure 1), despite comparable pain medication and the option for individual additional medication, a significant improvement of pain sensations was elicited in the Bowen therapy group lasting for one and a half day. As this finding was not a prespecified main outcome variable in our trial, it has to be further investigated in future trials.
In our trial we could not detect an overall difference in the averaged VAS score between our three study groups within ten days after knee replacement surgery (standard therapy only, Bowen treatment, sham treatment). However, in sub-analysis a significant pain reduction of within the first 36 hours after surgery was to be noticed in the Bowen treatment group as compared to the other groups. Further trials are needed to definitely confirm this finding. Based on the possible benefit, this therapy which is low in side effects can be regarded as an interesting additional tool in postoperative pain management.
Conflict of interest
Both, the first and second author have personal or family ties to Bowen therapists. In order to overcome a potential conflict of interest due to this circumstance in the best possible way,
maintaining impartiality was given highest priority: By either being blinded to the kind of treatment (first author) or trying to keep an unbiased point of view throughout the trial (second author who administered Bowen therapy as well as sham treatment).
The statistical analysis was generously funded by grants of the Upper Austrian Medical Society and the Upper Austrian Society for Medical Sciences.
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2 Machacek P. et al; Die postoperative Schmerztherapie nach Orthopädischen Eingriffen; Clinicum Orthopädie Sonderausgabe September 2009
3 Wilks J.; The Bowen Technique – The Inside Story; The Knee S.
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4 Whitaker.J.A.. Gilliam.P.P.. Seba. D.B. (1997). The Bowen Technique: a Gentle Hands-on Method That Affects the Autonomic Nervous System as Measured by Heart Rate Variability and Clinical Assessment. Abstract presentation American Academy of Environmental Medicine 32nd Annual Conference La Jolla California