A comparison of multidisciplinary team residential rehabilitation with conventional outpatient care for the treatment of non-arthritic intra-articular hip pain in UK Military personnel – a protocol for a randomised controlled trial

To date, patient outcomes after treatment of intra-articular hip disorders have been limited to post-surgical outcomes [11, 12]. Consequently, comprehensive treatment outside of surgery remains ill-defined [1]. Although the success of conservative management for non-arthritic, intra-articular hip pain is inconclusive [10], positive results have been reported in two recent publications [1, 13]. Hunt et al. [1] and Emara et al. [13] reported outcomes of conservative care for patients with clinical indicators of non-arthritic, intra-articular hip pain. Both studies demonstrated significant improvements in pain and physical function from baseline to +1-year follow-up. The observational nature of these studies prevent speculation on the mechanisms underpinning the effectiveness of conservative treatment, however, these are important findings as many experts had previously concluded there was no role for conservative treatment [10].

A recent systematic review found the experimental evidence reporting non-operative treatment for FAI is limited to 5 articles providing a low-level of evidence [10]. Whilst limited the experimental evidence promotes physical therapy led care for FAI. Fundamental to all regimens is an exercise-based programme focused on the core hip musculature, individually tailored strengthening exercises, manual therapy, home-based exercise and education. In addition, the early use of simple analgesia and NSAIDs is promoted. Whilst there is a suggestion that this form of physical therapy and education confer some benefit to patients, the literature is not supported by any randomised controlled trials, and conservative treatment regimens need to be evaluated more extensively and rigorously to determine the true clinical effectiveness [1, 5, 10, 13].

Abnormal femoroacetabular morphology is commonly seen in young men comprising much of the UK military population [14]. Residential multidisciplinary team (MDT) rehabilitation for patients with musculoskeletal injuries has a long tradition in the UK military. Rehabilitation most often takes place in two clinical settings; out-patient primary care rehabilitation facilities (PCRF), and specialist in-patient residential centres. Rehabilitation at the PCRF is focussed primarily on physical function led by a physiotherapist, whereas residential centres have access to larger consultant led multidisciplinary teams delivering a broader psychosocial approach to treatment. However, whilst single treatment entities for hip conditions have been the subject of evidence-based examination, there has been little evaluation of group-based MDT management programmes combining single treatments. Aprile et al. [15], showed no statistically significant difference between outpatient/individual versus inpatient/group hip rehabilitation for any validated clinical outcome measure. Angst et al. [16] found comprehensive inpatient team rehabilitation led to statistically and clinically important improvements in pain and function for patients with co-morbid hip pain. However, there are no studies presenting empirical data on the structure and process of non-arthritic hip pain care for a young active military cohort, or whether a broader residential MDT approach provides better care than individualised conventional outpatient treatment.

With no available data, the effectiveness of MDT residential care remains unclear. Therefore, the purpose of this study is to compare the effects of a residential, multidisciplinary intervention, to usual outpatient care, on the clinical outcomes of UK military patients undergoing treatment for non-arthritic intra-articular hip pain. This protocol describes the design and analysis plan for a randomised controlled trial.

The primary aim of this study is to compare the effects of a 7-day residential multidisciplinary intervention, to usual outpatient care, on pain and physical function in military patients with non-arthritic intra-articular hip pain.

The secondary aims are to assess changes in relevant musculoskeletal variables of treatment including hip range of motion (HROM), walking ability, and postural control during single leg stance. The primary time point is measured at 3-months (12-weeks).

No studies have compared the effects of MDT residential rehabilitation interventions versus conventional outpatient care for non-arthritic hip pain. However, systematic reviews and RCT’s provide evidence that MDT inpatient rehabilitation programmes are more effective than usual care (moderate evidence) to improve pain, well-being and self-reported function in heterogeneous patient groups with musculoskeletal conditions [17‐20]. Therefore, we will test the following primary hypothesis:

There is evidence from RCT’s showing that a greater number of therapist contacts and higher intensity rehabilitation improves rehabilitation outcomes in patients with musculoskeletal pathology [21, 22]. This suggests a dose-response for treatment/training outcomes [23]. Class-based supervised exercise rehabilitation has also been shown to improve health outcomes compared to a non-supervised home-based group [24]. In our study a residential rehabilitation group will receive a period of intensive, supervised class-based treatment. An outpatient group will undergo a series of regular clinic appointments combined with unsupervised home-based exercise. We will test the following secondary hypothesis:

The study is a superiority parallel-group, randomised controlled trial (RCT) of a 7-day residential, multidisciplinary intervention (MTD programme), and individualised physiotherapy outpatient care (IP programme) with 3-month follow-up. Measurements will be taken at baseline, post-treatment (7-day MDT; 6-weeks IP) and 12-weeks. We considered including a sham control treatment group but felt in a well-motivated young military cohort this could have a negative impact on recruitment. Trial participants, assessors and clinical/research staff will be un-blinded to treatment allocation. The protocol will conform to the CONSORT (Consolidation of Standards of Reporting Trials) guidelines for non-pharmacological interventions [25], and principles of the Declaration of Helsinki [26].

The study will be conducted at a specialist UK military rehabilitation centre.

The study has been reviewed and approved by the UK Ministry of Defence (MOD) research ethics committee (study reference protocol 576 dated 01 Nov 2014). Any requirement for protocol modifications will be submitted for authorisation to the MOD research ethics committee.

We will recruit 100 male participants aged 18 to 50 years attending the Centre for Lower Limb Rehabilitation injury assessment clinic (Defence Medical Rehabilitation Centre (DMRC), Headley Court, UK) with symptoms of intra-articular non-arthritic hip pain. Eligible participants must meet the criteria detailed in Table 1.

The procedure and flow of participants is outlined in Fig. 1. Patients with symptoms of hip pain will undergo preliminary screening conducted by their local unit medical officer. The only screening criteria used at this initial stage is the patient reporting symptoms of hip/groin pain for at least 3-months. Potential participants will then attend a multidisciplinary injury assessment clinic (MIAC) at DMRC for a comprehensive musculoskeletal examination by a specialist rehabilitation consultant, and experienced musculoskeletal physiotherapist. The purpose of the MIAC is to establish the patient’s eligibility for inclusion in the study. Because attendance at the MIAC is directly linked to this study, patient consent to attend the MIAC will be sought in advance via postal consent forms and a patient information sheet, and follow-up telephone calls from study administrators where necessary. The information sheet will detail the nature of the study and will include confirmation that consenting eligible participants will be randomly assigned to one of the following two treatment groups:

A definition of rehabilitation based on the concepts of structure and process is frequently used when assessing the content of health care interventions [32]. In our study the therapeutic content (e.g., exercise, manual therapy, education, home-based programme) is the same for both study groups. However, the structure and process will differ significantly. The residential arm is group treatment delivered by a MDT in a residential setting over 7-days. The outpatient arm is physiotherapist led individual treatment delivered during a series of weekly appointments over 6-weeks. Therefore, the amount of direct therapist contact, hands-on physical therapy and instructions surrounding exercise adjustment and education will differ. A detailed description of the treatment methods is contained in Table 3 and Additional file 1.

Eligible patients will be invited to participate in the study and complete an informed consent form. Patients agreeing to participate will be informed of treatment group assignment and referral arrangements by a civilian member of the clinical team, and all necessary study documents will also be provided. Ineligible patients will receive an ongoing referral in accordance with the existing UK military best practice care pathway. Following consent, participants will be consecutively randomised into either the residential or outpatient group by an independent administrator not involved in recruitment, assessment or treatment of participants. Baseline testing will be conducted immediately prior to commencement of treatment. Participants will be reassessed on completion of treatment (1-week (MDT); 6-weeks (IP)), and again at 12-weeks (week 12). During the 12-week follow up period, all participants will be advised to continue with an unsupervised home exercise programme. A log book record of exercise participation will be maintained during this period, and participants will be asked to refrain from seeking other treatments during the study.

A block randomisation method will be used to randomise subjects into groups that result in equal sample sizes. This method will ensure a balance in sample size across both groups over time. Blocks are small and balanced with pre-determined group assignments, which keeps the numbers of subjects in each group similar at all times, whilst ensuring there is a 50:50 likelihood of participants being allocated to either group. Due to the possible influence of gender on the efficacy of strengthening exercise [32, 33], the study will only recruit male participants. After patient eligibility has been confirmed and informed consent obtained, a sealed envelope will be opened to reveal group allocation by an independent administrator not involved in the recruitment, treatment or assessment of study outcomes. A plain language statement will inform participants that they have an equal chance of receiving the residential MDT or individualised outpatient intervention. Group allocation will be documented and communicated to the supervising therapists by the independent administrator. Prior to the study, all treating staff will have received a briefing on the study protocol, the ethical, clinical and scientific basis of the study, the randomisation process and specific intervention for each treatment group, in line with the study protocol. It is not possible, relevant or necessary to blind participants to treatment allocation in this study. The clinical staff supervising both groups will be, by necessity, unblinded. Day and Altman [34] suggest blinding assessment by using non-involved assessors to record outcome scores. This is not possible in our study as independent assessors with specific knowledge of quantification of clinical outcomes are not available due to specialist staff man-power limitations. To minimise the potential influence of outcome assessors, instructions are standardised to ensure consistency in measurement. A medical statistician assisting with statistical analysis will be blind to group allocation until completion of the analysis.

The content and protocols for the study interventions are described in a MILO study intervention guide [see Additional file 1]. Table 2 provides a summary of the components of the MDT residential intervention. Table 3 provides an overview of the IP and MDT treatment schedules. Following the recommendations of Bennell et al. [29], a systematic approach to designing all aspects of the intervention has been adopted that ensures it is based on theory, evidence, reflects elements of best practice, and is reproducible and reportable. The MDT residential and IP outpatient group programmes in this study will employ a semi-structured protocol, which provides guidance on exercise prescription, but can be tailored to meet individual patient assessment findings and progression. Written guidelines for individual tailoring of activity and treatment prescription will be provided to supervising therapists. Designing a patient care plan that is individually tailored from a standardised menu of interventions ensures our methodology is consistent with the ‘ideal standard of clinical practice’ [35], and research designs of previous studies [5, 27, 29, 36, 37]. The IP outpatient intervention will be administered by a senior chartered physiotherapist. A broader MDT including specialist physician, physiotherapist, occupational therapist, exercise rehabilitation specialist and nutritionist at DMRC will deliver the residential programme. All treating therapists will attend a training session at DMRC which will focus on the exercise, manual therapy and education interventions to ensure a standardised approach to treatment across both interventions and therapy staff. Whilst the delivery of therapeutic interventions by several MDT staff risks an increase in treatment variation through the influence of therapist personality and style, it allows a more practical delivery mode that mimics clinical practice, and will enhance the generalisibility of study findings [5].

The goals of treatment are the same for both the residential and outpatient groups. The specific programme design will differ to reflect the contrasting structure in each setting, and to accommodate the individual participant progression. The core components of treatment are as follows:

It is beyond the scope of this study protocol paper to detail every individual exercise used in the study interventions. The exercise programme incorporates strengthening, flexibility/range of motion, and functional balance and neuromuscular control exercises in accordance with current evidence-based guidelines, and exercise recommendations for the conservative management of intra-articular hip disorders [1, 10, 13].

Manual therapy techniques will be used to modify the quality and range of motion of the hip and associated soft tissue structures, and assist with pain relief. The manual therapy intervention will be prescribed individually for each participant on the basis of the physical examination findings, from a limited list of techniques including trigger point massage, passive joint mobilisation, distraction and sustained stretches. These techniques are informed by evidence-based best practice and are commonly used in the management of hip dysfunction [5, 30, 36]. Lumbar spine mobilisation, in the form of passive accessory intervertebral movements, will be performed in those patients where the physiotherapy assessment identifies a requirement [5].

Educating the patient on factors surrounding their treatment and the importance of regular exercise could be a key element for patient adherence to a home-based exercise programme [51, 52]. Education and advice will be a focus of the intervention and will include information on diagnosis and aetiology of FAI/hip pain, rationale for treatment, the benefits of exercise, joint protection and activity modification strategies, pain management, coping with acts of daily living (sitting, driving, sleeping, work), and the importance of increasing physical activity levels in everyday life. The contents of the education component will be evidence-based [10, 40] with the overall focus directed towards increasing the knowledge of the participant on issues surrounding their condition.

Participants will be instructed to complete an individualised, unsupervised home exercise programme during the 12-week follow-up period. This programme is prescribed by the physiotherapist at the final treatment session. To optimise adherence, the programme will comprise four to six exercises performed three times per week [29, 30, 35]. The selected exercises will reflect the patient’s clinical priorities for treatment determined by the physiotherapist on completion of the supervised phase of the protocol. The home exercise programme will comprise any combination of strengthening, stretching, neuromuscular control and aerobic exercise. The starting level will reflect the participant’s functional capabilities upon commencement of the follow-up training period. Guidance on exercise progression will also be provided, and participants will receive written instructions demonstrating the home exercises. Participants will be asked to report all training sessions in training diaries. Diary records will be used to measure compliance to the home programme. A goal is that participants should complete a minimum of 80 % of the prescribed exercise sessions [50].

Outcome measures with proven validity and reliability have been selected based on those recommended for clinical trials of intra-articular FAI [53], and current practice in UK military rehabilitation [54]. Standardised instruments recommended by OMERACT-OARSI guidelines [55] will also be included. These guidelines require measures of pain, physical function and a global assessment of health related quality of life. Participants will be assessed at baseline, on completion of treatment (1-week MDT group; 6-weeks IP group) and 12-weeks follow up (Fig. 1). The follow-up time-frames are the same for both groups (12-weeks), and all participants will be assessed at baseline and 12-weeks on the same clinical outcome measures. The inclusion of post-treatment measures may help reveal if any differences occur as a consequence of the different interventions (e.g., the immediate post-treatment scores by group). All outcome measures will be conducted, administered and overseen by the same supervising therapist on each occasion. Outcome measures used in the study are summarised in Table 4.

The primary endpoint will be change from baseline to 12-weeks in (a) the HAGOS ‘physical function in daily living’ subscale and (b) VAS numeric pain rating. Sample size calculation is based on clinically relevant changes over the study period (e.g., score changes between baseline and follow-up should be, on average, subjectively perceptible by the participant). The minimum clinically important difference (MCID) in the HAGOS subscale has been suggested to be 4.8–5.2 points [53]. Between participant standard deviations have not been widely reported for the VAS using intra-articular hip pain patients [1, 10]. Therefore, the required sample using a MCID of 5.2 between groups on the HAGOS subscale and a standard deviation of 11 points, with a significance level of 0.05 (2 tailed) and a power of 80 %, is 43 per group. Allowing for an estimated drop out rate of approximately 15 % at the 12-week follow-up, a total of 100 participants will be recruited into the study. Based on current referral rates it is anticipated this sample target will be met from routine referrals to DMRC Headley Court and no additional strategies to promote enrolment are required. The sample size was calculated using G*Power software Version 3.0.10 (Franz Faul, Universitaet Kiel, Germany). There is currently no RCT reporting the effects of a residential MDT intervention versus outpatient individualised treatment approaching this sample size in the available literature.

The statistical analysis will be undertaken in accordance with the intention-to-treat (ITT) principle. The ITT analysis will include all participants, including those who do not fully adhere to the protocol and those with missing outcome data. A per-protocol analysis will also be performed where appropriate. Demographic and clinical characteristics as well as baseline data will be presented to assess the baseline comparability of the two groups. Differences from baseline to each time point will be calculated for all primary and secondary outcomes. Descriptive statistics will be presented for each group as mean change, standard deviations and confidence intervals (CI) for continuous variables, and frequencies and percentages for categorical variables. A longitudinal repeated measures design will be used to assess changes from baseline, and to make between group comparisons for the continuous outcome measures. Between group comparisons will be made immediately post treatment (1 week residential group; 6 weeks outpatient group) and at 12 weeks.

The effect of the interventions over time will be compared using linear and mixed models. These models are chosen as they appropriately adjust for correlation that occurs from collecting multiple observations per participant [37]. At the 1,6 and 12 week time points, continuous variables will be analysed using a mixed model repeated-measure analysis of variance (ANOVA) model (with treatment as the between group factor and time as the repeated factor). The non-parametric equivalent or data transformation will be used if non-normal distributions apply. Where significant differences occur, post-hoc comparisons will be conducted using Tukey’s multiple comparison procedure. Differences in nominal/ordinal data will be analysed using the χ² test. A significance level of 0.05 will be set for any inferential statistics conducted. The inclusion of the post treatment (T2) measure may help reveal if any differences occur as a consequence of the different interventions (as T2 reflects the immediate post-treatment scores for each group). However, this is based on the assumption that any changes in outcome from T1 and T2 (over 1 and 6-weeks) are linear, and also between T2 and T3. We recognise if the trend is non-linear then we will have insufficient data points to model the outcome over time in a way that will enable us to compare the trajectory of patient outcomes using the 3 time points. If interim analysis reveals this to be the case, we will remove T2 measures from the final analysis.

No statistical adjustment will be made for multiple testing. All tests will be two-sided and carried out at the 5 % level of significance. Changes to the study design or analysis plan will be documented with full justification. A statistician will oversee the blinded analyses of the data. The statistical analysis procedure will be discussed, reviewed and co-worked with statisticians at the Department for Health University of Bath, and School of Clinical Sciences at Bristol University.

All information obtained in the conduct of this study will be treated as confidential and participant anonymity will be ensured throughout the study period. Electronically stored data will be identified by a password-protected participant ID code unique to the study. We will transcribe data from paper forms directly into a bespoke Military Hip Rehabilitation Outcome (MILO) study relational database (Concentrica Ltd, Cambridge, UK) based on server’s in the Academic Department of Military Rehabilitation, DMRC and the Department for Health, University of Bath. To minimise transcription error, we will use manual double data entry. RC, JB, AW and AB will have access to the final trial dataset.

All researchers involved in the conduct and supervision of this study will receive extensive training in all aspects of the administration of the trial protocol. The training will comprise a 1-day programme delivered at DMRC Headley Court. All clinical and research staff will receive a brief detailing the procedures for identifying and reporting safety issues including the use of project adverse events forms. They will be informed of the role and responsibilities of the Independent Medical Officer (IMO) and the lead researcher who takes day-to-day responsibility for safety of the project. Reporting of safety incidents will be duplicated using existing DMRC clinical health and safety reporting procedures and in accordance with the principles of good clinical practice (GCP). In the unlikely event this study is prematurely terminated for any reason, the MoD research ethics committee will be informed and provided with the justification for this action.

We will submit the results of our study for publication in a suitable journal regardless of the outcomes. The trial will be reported in accordance with the CONSORT statement [25]. The chief investigator will take responsibility for producing draft report manuscripts and all co-investigators will review and approve the study results prior to submission for publication. Authorship of all manuscripts and presentations will comply with the ICMJE “Uniform requirements for Manuscripts Submitted to biomedical Journals” [87].

Ethics approval was obtained from the UK Ministry of Defence research ethics committee in August 2015. Recruitment of a study administrator was undertaken in November 2015. Participant recruitment and data collection will commence in January 2016. All recruitment and data collection are expected to be completed by December 2017.