What does standard rehabilitation practice after total hip replacement in the UK entail? results of a mixed methods study

Total hip replacement (THR) is one of the most widely performed procedures in orthopaedic practice and with the increasing age of the population; the number of persons who require such surgery is on the rise, [1]. In England and Wales, according to the National joint registry, the number of primary total hip replacements (THR) in 2009/2010 totalled 79413, which is a steady rise from the amount reported in 2008/2009 (77608) and 2007/2008 (73632), [2]. THR has revolutionalised the care of patients with end stage joint disease, leading to pain relief, and substantial improvement in quality of life, [3]. However, long-term studies show that, even in the absence of pain, there is persistence of impairment and functional limitation, [4]. These long lasting impairments include reduced muscle strength, reduced postural stability, and limited flexibility, [5]. The functional limitations include reduced walking speed, and lower ratings on various assessment tools used to measure functional ability compared with those who have never had hip arthritis, [5].

Considerable technical efforts have been made towards optimising THR; for example, there are over 100 varieties of hip prostheses, multiple bearing couples, and several surgical approaches. However, the actual health gain for many of these innovations is small in terms of patient function and quality of life, [6]. In tandem with these technical developments, patient expectations, including for an early return to normal physical function and activities; have also increased, [7]. In the recent past, a prolonged hospital stay after THR incorporated a period of rehabilitation. However, due to the introduction of initiatives such as integrated care pathways and considerations of cost and patient satisfaction, the length of hospital stay following joint replacement has reduced markedly over the past decade from a mean of 3 weeks to 4 days [8].

Since the evidence suggests patients who score poorly on subjectively assessed functional outcome measures 2 years post-operatively after THR are five times more likely to require assistance with ADLs compared to those who have good function, [9], rehabilitation may therefore increasingly important to avoid long-term impairment and to optimise functional recovery, [5].

Prior to surgery, there is a general deficit in muscular strength along the affected limb as compared to the contra-lateral (healthy) side in patients with unilateral hip osteoarthritis (OA), and muscles such as the abductors, vastii, rectus femoris and psoas show marked atrophy, [10]. Immobilisation due to major surgery and hospitalisation can cause a further decline in muscle mass, muscle strength and muscle function, [11]. Muscle strength declines 4% per day during the first week of immobilisation, and the deficits in the involved hip after THR range from 10-21% when compared to the uninvolved hip at 1 year post-surgery, [12, 13] the atrophic changes that occur about the hip persist up to 2 years following THR, [10].

The most commonly used rehabilitation regimes for older people are based on functional types of exercises which do not involve external loading and have not been shown to prevent further muscle atrophy after THR [5, 14]. In contrast, progressive resistance training (PRT) is an effective method for inducing muscle hypertrophy and increasing muscle strength and functional performance in healthy and clinical populations, including the elderly, [15]. PRT elicits positive health and performance adaptations by challenging the skeletal muscles with loads that can be lifted repetitively until the onset of neuromuscular fatigue, i.e. the point at which appropriate technique can no longer be maintained, [15]. To facilitate continued adaptation, training load is progressively increased, and exercises are adjusted as indicated throughout the training regimen, to attenuate the onset of a plateau in physiological adaptation.

PRT in rehabilitation following THR has been shown to significantly enhance muscle strength and function, [16–18] with PRT being the main factor in achieving significant functional improvements in rehabilitation regimes used after home or centre based regimes used after THR, [19]. Although a plethora of studies exist testing different rehabilitation protocols (including PRT) against ‘standard’ practice, [20, 21] no explicit definition is made as to what ‘standard practice’ entails. Clarification of the variation in the available rehabilitation programs after this common operation is therefore important. The aims of this study were firstly to define standard rehabilitation care following THR in the UK and secondarily to determine whether PRT is prescribed as part of standard care.

After local NHS Research Ethics Committee approval, a focus group interview was convened. A heterogenous sample of physiotherapy participants were purposively sampled using the following criteria: 1) a minimum of 5 years experience post-qualification, 2) experience of treating patients following THR and 3) working in either the inpatient, outpatient and community environment with patients following THR. The participants were accessed through physiotherapy management leads that provided a suitable list and the above criterion were used to approach potential candidates. Of the four physiotherapists subsequently recruited, two worked in the hospital setting, one worked in the community and the other was outpatient based.

After informed consent, the focus group was conducted by the first author (TO; main moderator) with a co-author (AR) acting as a co-moderator and scribe. A number of topic areas were discussed with the group with the questions posed based on a preliminary review of the literature from which a number of gaps appeared [20, 21].

106 responses were received from physiotherapists who supervise rehabilitation of THR patients in the UK. Of these, 85% worked in the NHS and 15% in the private sector. 104 out of 106 physiotherapists (98.1%) who responded were Band 5 and above (average of 5 years post-qualification experience), and 94% of all respondents worked in centres performing greater than 100 THR operations per year, Table 3. The responses to the questions posed in each of the rehabilitation phases are detailed below:

Despite 83.7% of the survey respondents being able to ascertain what PRT entailed, only 33% routinely built it into their prescribed rehabilitation programs. 48% of the survey respondents who treated THR patients in the outpatient setting reported that weak hip abductors accounted for the majority of referrals in the ‘continuing rehabilitation’ phase, with poor balance accounting for 34%, and prescriptions given were mainly of functional, weight bearing and bed exercises. The reasons for referral reflect a lack of muscle strength which is consistent with the established findings after THR as already described [10]. The use of PRT therefore helps address this deficit and prevent further muscle atrophy.

This is the first study in the published literature that attempts to quantify the standard practice for physiotherapy rehabilitation following THR surgery in the UK. Recent systematic reviews have looked at programmes and interventions to improve functional outcome in this group of patients, [19–21] and a common observation made is the variety in the ‘standard’ or control regimes that are used for comparison. With the inpatient stay reduced to an average of 4 days as reported by a majority of the physiotherapists surveyed in this study, intervening following patient discharge from hospital is increasingly important if the persisting functional deficits typical of these patients are to be resolved.

In the preoperative phase of rehabilitation, 67.9% of the U.K. physiotherapists surveyed had contact with patients in a variety of settings. Preoperative counselling and education reduces unrealistic expectations regarding pain as well as improves patient satisfaction, [24]. Preoperative physiotherapy on the other hand reportedly improves muscle strength and gait, allowing early return to ambulatory function, [20] but its impact on short-term outcome such as gait speed, cadence, walking distance is debatable as the trials performed also include post-operative interventions on the same cohort of patients, [20]. The uses of the techniques described (arthroplasty education seminar, trust booklets, etc.) are therefore advantageous and exercise prescription in this phase of rehabilitation did not emerge as a theme from the convened focus group.

Due to the current financial pressures the NHS is under with staffing levels and patient throughput, [25], the primary objective for the majority of physiotherapists may be to mobilise the patients for discharge. Criteria used include stability with a walking aid, compliance with the prescribed exercises, and independence with ADLs. Inherently therefore the objective is to aim for safety on mobilisation and functional optimisation is not top of the agenda. Possible issues that may hinder physiotherapists in using PRT include time constraints as already described with possibly referral patterns, difficulties in transporting patients to a gym setting, and the demand on inpatient services meaning that the primary objective for the majority of working physiotherapists is to aim for safety on mobilisation. As intervening to improve function is increasingly difficult to commence in the hospital setting due to the pressures to achieve a short inpatient stay, referral to community physiotherapy to continue appropriate regimes may be what is required. There are inherent difficulties with this approach as 74.5% of the survey respondents did not routinely do this, illustrating the difficulties of adapting practice to reflect the significant evidence base. It is also possible that the closed nature of the question posed in the questionnaire meant that some physiotherapists who may include an element of PRT occasionally in the regimes prescribed responded negatively. Patients may not be routinely referred to outpatient physiotherapy post-operatively perhaps due to different local protocols and guidelines with care funding packages. It was also evident from the focus group discussion that routine outpatient assessment post-operatively was not considered except patients were anticipated to have problems with mobilization.

The orthopaedic surgeons’ role in the rehabilitation recommendations is mainly determined by the integrity of the implants used. Recent literature suggests that early full weight bearing with cementless implants may have no significant impact on primary stability and bony ingrowth [26] making exercise prescription by physiotherapists in the early post-operative phase more relevant.

From the 7^th annual report of the NJR in 2010, [2], 392 centres entered data on the numbers of THR surgery performed up to the year end in 2009. Of the 106 survey respondents, 100 (94%) worked in centres performing >100 THR procedures per year (217/392 centres according to the NJR data) perhaps implying that about half of the hospitals listed were surveyed. A more comprehensive survey of these centres may have provided more generalizable information but this was inherently difficult as only 63 emails addresses were obtained from 171 hospitals contacted (36.8%). The remainder of responses obtained can be assumed to be from a combination of colleagues of those in whom emails were sent as well as physiotherapists with access to the CSP website.

The use of the focus group to determine the questionnaire items for the survey further validates the findings obtained. This survey aimed to determine ‘standard’ practice and the 4 physiotherapists used in the focus group were from a mixture of backgrounds but all treated THR patients regularly. Since no questionnaire existed to achieve the aim of this study, the focus group ensured that the items obtained helped clarify any underlying assumptions of personal or traditional practice such as frequency of times patients need to be seen, exercises that should be prescribed, etc. Sources of information and experience as well perspectives and viewpoints of the professional group to be studied are also better integrated using this method of qualitative research [27]. The focus group participants in this instance were more likely to feel a sense of community and belonging which makes them more comfortable and more willing to express opinions [27], therefore ensuring that the items obtained for the questionnaire used reflect the pre-operative, post-operative and continuing rehabilitation phases as already described.

A limitation of this study is the fact that no analysis of regional variations in practice was performed. This was in part due to an effort to anonymise the data obtained so as to preserve the confidentiality of respondents as required by the ethics committee. An effort was also made not to identify areas which may have huge disparity in service provision from the norm. Further information may also have been gleaned from content analysis of the preoperative advice and instructions given to patients in the form of booklets, videos and CDs. Such an undertaking was not feasible in this instance but perhaps can be part of a future study to further clarify what standard THR rehabilitation regimes entail.

THR surgery is an increasingly common operation for hip osteoarthritis. This survey demonstrates that physiotherapy practice in the UK rarely includes progressive resistance exercise; and this may be a factor in prolonged poor function in some patients. Future research should focus on the issues restricting implementation of suitable PRT regimes to improve functional outcome.