This two-armed randomized controlled trial (RCT) aims to investigate the effectiveness of Group Exercise with acceptance and commitment therapy led by physiotherapist (GrExPACT) (experimental intervention) as compared to Group Exercise alone (GrEx) (control intervention) for elderly with chronic low back pain (LBP) whom are stratified as medium or high-risk using the STarT Back Screening Tool on functional recovery as measured by Roland Morris Disability Questionnaire as the primary outcome and a list of secondary outcomes which include Committed Action questionnaire, Chronic Pain Acceptance questionnaire, Patient self-efficacy Questionnaire, Brief Pain Inventory, Patient Specific Functional Scale, Short Physical Performance Battery and a patient satisfaction survey, immediately after a 5-week programme as well as at 3-month follow-up.

The list of hypotheses to be tested in this RCT include:

1. For main effect: Intervention H0: The outcome means for the intervention of GrExPACT and GrEx are equal H1: The outcome means for the intervention of GrExPACT and GrEx are not equal
2. For main effect: Time H0: The outcome means for the time with measuring point at pre-intervention, immediate after the program and at 3 months are equal H1: The outcome means for the time with measuring point at pre-intervention, immediate after the program and at 3 months are not equal
3. For interaction: Intervention x Time H0: There is no interaction between the intervention and time H1: There is interaction between the intervention and time

Sample size:

The sample size was calculated with reference to the effect size of 0.052 (partial eta square) being worked out from the primary outcome of Roland Morris Disability Questionnaire obtained from the pilot study. G*Power 3.1.9.4 was used to calculate the sample size. With power of 0.95 and alpha value of 0.05, the total sample size is 68. With reference to the attrition rate of approximately 20% in the pilot study, the sample size will become 43 subjects in each group and with total of 86 subjects will be recruited.Subjects will be recruited from local community elderly community centers.

Randomization:

The subjects will be randomly assigned by the principal investigator to either intervention group of GrExPACT or control group of GrEx using computerized randomization software. Permuted blocked randomization with a block size of four and stratified by gender and STarT Back category will be used as to ensure the groups are balanced. The allocation will be concealed and stored in an encrypted file storing in a password protected computer. Corresponding group therapy class will be arranged to the patient accordingly.

Study design:

86 subjects with chronic nonspecific LBP subject will first receive a 30-minute triage screening by a physiotherapist for inclusion criteria, exclusion criteria and red flags as to confirm the subjects are belonging to chronic nonspecific LBP and is suitable for the study. The red flags include night pain, 24-hour pain, unexplained weight loss, night sweats, fever, change in bowel and urinary habits and saddle anesthesia. Subjective examination for body chart and physical examination include trunk range of motion, myotome, dermatome, reflexes, palpation, and neuro-tension test will be performed when applicable.

Each subject will participate weekly group program for five consecutive weeks after the group randomization. The size of the group is about 10. Each session for both intervention group and control group will last for 105 min and will receive 60-minute group exercise therapy includes supervised stretching, mobilization, stabilization and strengthening exercise for the muscles around lumbar, hips and low limbs followed by functional and aerobic training. The exercises are selected with reference to the National Institute for health and care Excellence (NICE) guidelines, systematic review for physical activities for elderly with chronic LBP and experience from the previous pilot trial which is safe and effective for elderly with nonspecific chronic LBP. The exercise will be taught to patient progressively from lying to sitting in first two sessions and adding more advance standing to functional and aerobic training in subsequent sessions. The resistance of the TheraBand and step height for functional training will tailor made and increase according to individual capability. Each patient will be given an exercise pamphlet, goal setting worksheet and home exercise record sheet. Patients are encouraged to utilize local community exercise facilitates and bring back the home exercise record sheet each time for checking of compliance of practicing home exercise.

Both groups of patients will have a physiotherapist leading discussion. For the GrEx group, the discussion will last for 45 minutes. It involves discussion for back care and exercise referencing to the back school that is a common educational and training program given to patients with low back pain. The content includes anatomy of the spine, cause for pain, self-management, correct manual lifting technique, ergonomic advice, and benefit of regular exercise. For the GrExPACT group, the discussion will use the Acceptance and Commitment Therapy (ACT) approach and will also last for 45 minutes. The content of the discussion will follow the protocol-based ACT extracted from the protocol for the contextual pain management by physiotherapy being used in INPUT center of St Thomas Hospital, London and physiotherapy informed by acceptance and commitment therapy protocol (PACT) .

Qualification of the intervention provider:

The intervention providers are registered physiotherapist in Hong Kong who had more than 30 years of clinical experience in treating patient with musculoskeletal problem at public physiotherapist outpatient clinic. For the background of ACT training, the physiotherapists had received training for taught course for ACT and had participated in a two-day clinical attachment for the contextual pain management program in INPUT Center at St. Thomas Hospital in London of United Kingdom in 2018. Besides the participation in the local pilot trial for GrExPACT study, they had also participated in the development for the local clinical service team for stratified care and combined the physical and psychological approach in management of high-risk back pain patients since 2015.

Data processing and statistical analysis:

The statistical analysis will be carried out using IBM SPSS version 28 software. The demographically data will be presented by descriptive statistics. For continuous data, it will be presented as mean, standard deviation and range. For categorical data, it will be presented as frequency and percentage. Normality will be first screened by Boxplot, and further assessed by the Shapiro-Wilk test. For the primary and secondary outcomes, two way repeated measure ANOVA will be carried out. For the effect of time, the post hoc test will be carried out for testing the differences of outcome scores for pre-intervention verse immediate after the program; pre-intervention verse at 3 months; and immediate after the program verse at 3 months. For the effect of intervention, post hoc tests at each time point will be carried out when necessary. Significance was set at p < 0.05. Intention-to-treat analysis will be used and missing data will be replaced with data from the nearest previous non-missing data. Effect sizes (Partial eta squared) will also be computed to establish the magnitude of the treatment effects. The effect sizes will interpreted as small (η2=0.01), medium (η2=0.06) or large (η2=0.14).

Clinical significance:

In the management of elderly patient with chronic nonspecific low back pain (LBP), to face the aging population, growing high patient volume and limited resources in health care, an effective and efficient service model is urged. The service model of GrExPACT in the present randomized control trial involve tailor made and resources saving strategy by using concept of stratified care with STarT Back Screening Tool, physical therapy with group exercise and psychological therapy with group ACT lead by physiotherapist. With the present study, the effectiveness, synergistic effect, and adaptability to local culture for combining physiotherapy group exercise with acceptance and commitment therapy delivered by physiotherapist (GrExPACT) could be studied. The potential positive finding may enhance the role of physiotherapist using the psychological approach in the management of chronic nonspecific LBP and provide evidence support for the proposed more comprehensive, tailor made and resources saving service model of GrExPACT. This may help to reform a more effective and efficient model of care in Hong Kong.

Inclusion Criteria

1. Ages ≥ 65;
2. Nonspecific LBP for > 3 month;
3. Stratified as medium-risk category (i.e., total score ≥ 4 and sub score ≤ to 3) and high-risk category (i.e., total score ≥ 4 and sub score ≥ 4) using the STarT Back Screening Tool;
4. Roland Morris Disability Questionnaire (RMDQ) score ≥ 5 (with reference to the minimal level of detectable change)(30, 31);
5. Able to walk with or without assistive aid and with Modified Functional Ambulatory Category ≥ 6 (32);
6. Able to read Chinese characters;
7. Able to speak and understand Cantonese; and
8. Abbreviated mental test (AMT) ≥ 6 (33).

Exclusion Criteria

1. Specific cause of LBP such as tumor, infection, or apparent neurological deficit;
2. Serious uncontrolled co-morbidities or systematic diseases which is contraindicated to exercise;
3. Orthopedic condition like recent fracture require immobilization and not fitting for exercise;
4. Unstable cardiac, pulmonary, metabolic, and psychological disease requiring acute care;
5. Severe cognitive, language or hearing deficits;
6. Spinal surgery in the past 12 months as not to confound with effect of surgery;
7. People who had prior treatment with ACT at any time; or
8. People who had received physiotherapy treatment in the previous 6 months.

Subjects will be blinded by informing them that they will participate in one of the two treatment groups that is known to be helpful to their chronic nonspecific back pain but not known which one is better. An independent assessor who is responsible for carrying out the physical test and assist the elderly in filling of the questionnaires will be blinded for the group allocation. The research personnel who is responsible for data entry and statistical analysis will also be blinded for the group allocation.