Introduction

Total knee replacement is a common surgical procedure for treatment of advanced osteoarthritis. Over 100,000 knee replacements were performed annually in the UK’s National Health Service (NHS) before the COVID-19 pandemic [1, 2]. Demand for knee replacement in the UK is projected to increase by over 40% by the year 2060 [3]. These rises are global: for instance, in the USA over 1 million people were predicted to receive a total knee replacement in 2020 [4]. While most patients benefit from knee replacement, 10–34% experience chronic post-surgical pain—pain that develops or increases in intensity after surgery and persists at least 3 afterwards [5, 6]. For instance, in a UK study, among 258,386 people with total or unicompartmental knee replacement, 16.9% reported chronic pain likely to affect their quality of life negatively at six months after their operation [7]. Some people with chronic pain after knee replacement experience considerable distress and report feeling abandoned by healthcare [8] or believe that nothing further can be done for their pain [9]. Prevention of the development of chronic pain among individuals who might be at higher risk has been suggested as a good approach, but such identification is known to be challenging [10]. This means that a focus on pain after surgery remains a key point for intervention, including because there has been no clear referral and treatment pathways in place for such individuals [11, 12].

The STAR care pathway is a multifaceted personalised care pathway for people with troublesome pain at three months after total knee replacement [13]. The pathway was designed in line with UK Medical Research Council guidance on complex intervention development [14].

The pathway comprises an assessment clinic appointment with a trained Extended Scope Practitioner (ESP: an allied health-care professional with specialist orthopaedic training), referral to existing services for treatment, and up to 6 follow-up telephone calls over 12 months. ESPs who delivered the pathway received specialised training in the assessment of patients with problematic knee replacements, that included a detailed intervention manual and ongoing support from the research team. The 1-hour assessment aims to identify potential underlying causes for chronic pain and enable timely onward referrals to services for treatment. The clinical and cost-effectiveness of the STAR care pathway was evaluated in a multi-centre randomised controlled trial [15]. Results of the trial were published in full in 2022: the pathway was found to be clinically effective and cost-effective for reducing pain severity and interference over a 1-year period for people with pain at 3 months after total knee replacement surgery [16].

As highlighted by David Beard in his commentary on the STAR trial, the design of the trial was a pragmatic, pathway-based design rather than a direct comparison of a highly specific intervention, and “one that usefully accounts for real-world variation in treatment content and fidelity” [17]. We therefore report here on the experiences of real-world delivery of the STAR care pathway within NHS hospitals during the published trial [16]. We suggest that understanding the implementation potential of the pathway provides information for healthcare providers that may wish to consider putting the intervention into practice. Specifically, we describe qualitative research about the experiences of the healthcare professionals who delivered the pathway during the trial. More broadly, understanding implementation of new interventions and how they become embedded into practice provides understanding the success or failure of interventions, and the factors that shape intervention outcomes [18].

This study sought to understand healthcare professionals’ experiences of putting the STAR care pathway into practice in a multi-centre randomised controlled trial. This aimed to identify and describe barriers or facilitators to implementation and to produce recommendations for any delivery of the pathway should providers wish to do so. These recommendations will inform future development of a training package, updated manual and recommendations for delivery in usual care.

Methods

We used qualitative methods to explore and characterise the experiences of healthcare professionals’ implementation of the STAR care pathway. Qualitative methods embedded in clinical trials play an important role in understanding experiences of implementation [18]. The study received University of Bristol Faculty of Health Sciences Research Ethics Committee approval (ref. 83162) on 1st May 2019 and HRA approval on 1st June 2019 (ref. 19/HRA/3168). Our reporting of research methods includes items of relevance to the study design and is in keeping with SRQR guidelines [19].

Results

Eleven PIs, and 10 ESPs from across the eight trial sites were invited to participate. Eight ESPs and six PIs from seven trial sites participated. All PIs were consultant knee surgeons and are referred to as consultants from hereon. All consultants were male. All ESPs were experienced musculoskeletal physiotherapists and included 4 males and 4 females. Participants had been in their role on the STAR project for between 18 months and 4 years at time of interview. The sites were located in North, Central and South England, and Wales. We have not provided a table of participant characteristics to protect anonymity.

We present the findings using the three general items from NoMAD, which aimed to elicit a global sense of the potential for normalization, and then the four core constructs from NPT. Subheadings describe the main implementation considerations apparent within each construct. Illustrative quotations relating to participants’ experiences are in S1–S5 Tables.

Discussion

We evaluated implementation of the STAR care pathway for chronic pain after knee replacement. The study elicited and explored views of the healthcare professionals involved in delivery of the care pathway in a randomised controlled trial. Allen and colleagues have emphasised the importance of incorporating conceptual frameworks to guide implementation in trials to enhance the translation of findings [29]. We used NPT, operationalised through NoMAD to frame collection of qualitative data. Our descriptive content analysis identified participants’ responses that mapped onto the four core constructs of NPT.

Our findings indicate that healthcare professionals quickly became familiar with the STAR care pathway and felt it had potential to become a normal part of their practice. ESPs were already familiar with many elements of the pathway in their current clinical roles. However, the pathway differed from normal practice in many respects: that the duration of the clinic provided patients with more opportunity to reflect on their experience of surgery and recovery; the pathway gave increased focus on identification of potential complications including neuropathic pain; and the pathway provided regular telephone follow-up. Healthcare professionals felt that decisions by healthcare providers about future implementation would depend on trial results. The results of the trial have now been published and indicate that the STAR care pathway is both clinically beneficial and cost-effective over a 1-year period for patients with chronic pain at 3 months after total knee replacement [16].

Our evaluation of the implementation potential of the STAR care pathway indicates that healthcare professionals valued the patient-centredness of the intervention. Training during the trial enabled and empowered ESPs to identify and provide support for patients at-risk of developing chronic post-surgical pain. During the trial, those with problematic knee replacements, were referred on to appropriate services. ESPs also valued the additional focus on neuropathic pain, which some had previously suspected was a cause of chronic post-surgical pain. This is supported by the baseline information about trial participants, which show that more than half reported neuropathic pain characteristics [30]. Previous research has shown that clinicians often struggle to help patients with chronic post-surgical pain because of a lack of clear guidance and referral pathways [11]. The STAR care pathway provides clear guidance on referral pathways and has formalised referral processes enabling ESPs to refer patients to appropriate services. We found that, across all seven included sites, healthcare professionals were open to working in new ways with the STAR care pathway and would continue to support it.

Potential challenges to implementation include the extra resources needed for the clinic and telephone follow-up, which required more time to deliver. Healthcare professionals felt there may be need for further funding and support from management. Some ESPs also felt that the telephone follow-ups may save time and costs compared with face-to-face consultations. In a separate interview study with patients who took part in the STAR trial, we found that patients derived reassurance and encouragement from the clinic and telephone calls [31].

A key aspect of implementation is the need for a collective understanding and awareness of the intervention. We found that in some centres, surgeons who were not directly involved in the trial did not know why patients whom they had treated were receiving assessment in a STAR clinic and who were sometimes referred back to them. Some were surprised or disappointed to see their patients in STAR having thought they were recovering well at the six-week post operative clinic appointment. We suggest that when implementing the STAR care pathway, all clinicians who provide support for patients with knee replacements should be made aware of and be engaged with the pathway and any changes in referral processes.

Our main theoretical contribution has been to extend the use of NPT to the implementation of a clinical care pathway for chronic post-surgical pain after knee replacement. Our findings complement those of a previous UK study, which shows that when successfully implemented, care pathways encourage a systematic approach that can improve referral and access to appropriate care, promoting person-centred care, better multidisciplinary communication, and management of at-risk patients [32]. In our study, training and support from the trial team, and the inclusion of orthopaedic consultants as PIs providing local leadership and management, ensured that ESP were well supported to deliver the pathway. Previous studies have shown that care pathway implementation can fail in sites where there is insufficient training or strong leadership [33]. We also found that implementation could be challenging if there is a lack of collective understanding. The core concept of coherence has been shown to be especially important where implementation can fail if there is a lack of collective understand about the purpose of the intervention amongst those delivering the intervention [34, 35]. We find this also extends to those involved in supporting patients receiving the intervention.

Conclusion

Our findings suggest that the STAR Care Pathway is supported by healthcare professionals who delivered it, and that it has the potential to be implemented successfully into practice. At the time of writing, the STAR care pathway has been adopted into usual care at one NHS hospital, and a training package is in development. Healthcare professionals valued the patient-centred nature of the care pathway and its use in identification of the nature of chronic post-surgical pain. Extended Scope Practitioners delivering the pathway felt it enabled them to refer patients to appropriate services. Wider learning from this study includes the importance of a collective understanding to support the successful implementation of an intervention. Implementation of an intervention is more likely to be successful if healthcare professionals—who may not be delivering the intervention but who support affected patients—are aware of and engaged with the intervention.

Supporting information

Acknowledgments

We thank all participants in the study for their time and expertise. We are also grateful to Mrs Gemma Munkenbeck, Research Administrator for her support throughout the study. The authors would like to acknowledge the following for their help and input into the STAR research programme: Andrew D Beswick, Tim J Peters, Emily Sanderson, Sian Noble, Ashley W. Blom, David A Walsh, Shaun Harris, Kirsty Garfield, Simon White, Andrew Toms, Andrew Judge, Athene Lane, Fiona MacKichan, Nicolas Ambler, Susan Bridgewater, Leigh Morrison, Gemma Munkenbeck, Candida McCabe, Rowenna Stroud, Kate Button, Nigel Arden, Andrew Price, Rafael Pinedo-Villaneuva, Anushka Soni, Stewart Long, Joanne Adams, and the public and patient representatives from the PEP-R group.