Targeting rehabilitation to improve outcomes after total knee arthroplasty in patients at risk of poor outcomes: randomised controlled trial

“Total knee arthroplasty is a common procedure for end stage osteoarthritis of the knee, with more than 100,000 knee arthroplasties performed each year in the United Kingdom and more than 700,000 in the United States. Projections of future surgical volumes suggest further substantial increases. Although total knee arthroscopy is effective at reducing pain and improving physical function for most patients, around 20% report dissatisfaction with the postoperative outcome.

[..] Meta-analyses suggest that uniform postoperative physiotherapy for all patients after total knee arthroplasty compared with no treatment offers short term benefit but is not effective at improving patient outcomes at one year. Further recent meta-analysis of randomised trials suggests no difference in patient outcomes when rehabilitation consists of home or outpatient based interventions after total knee arthroplasty (with conclusions based on weak to moderate evidence). [..] as most patients report a good result after total knee arthroplasty, it might be that subgroups of patients could benefit from a targeted physiotherapy intervention. We determined if a six week programme of outpatient physiotherapy offers superior outcomes to a home exercise based regimen when targeted, in the early postoperative phase, at patients with predicted poor recovery and clinical outcomes after total knee arthroplasty.

[..] To be eligible for the study, patients had to have undergone a primary total knee arthroplasty for osteoarthritis and be at risk of a poor outcome (defined as an Oxford knee score of ≤26 points, completed at that six week postoperative time point). The Oxford knee score measures pain and function after knee arthroplasty. The defined cut point of 26 points highlights those patients with most knee specific pain and dysfunction from simple activities, such as raising from a chair or mobilising a short distance. We excluded patients who were unwilling or unable to comply with the rehabilitation protocols, underwent arthroplasty purely for pain relief (ie, those with no expectation of mobilising postoperatively), required complex revision procedures, could not, or were unwilling to, attend their local outpatient department for rehabilitation, or had already received structured ongoing outpatient physiotherapy at six weeks post-surgery.

[..] All participants were reviewed by a physiotherapist two weeks after recruitment (eight weeks after total knee arthroplasty), at which point they were provided with rehabilitation advice and education about recovery, pain management, and pacing of activities. The participants then commenced 18 exercise sessions over six weeks and documented their exercise in a rehabilitation diary. On completion of the six week intervention all participants received a final session with the physiotherapist to review progress.

[..] The outpatient therapist led group undertook a progressive functional rehabilitation protocol (reviewed and modified weekly in a one-to-one contact session). The specific rehabilitation intervention for this study was based on best evidence for functional outcome.19 We used a goal led protocol that incorporated four categories: range of motion, strengthening, proprioception, and walking gait. Rehabilitation focused on agreed patient goals within these categories, with amendments over the six weeks as required.

[..] The home exercise based group comprised a minimum standard-of-care intervention that reflects the provision of postoperative physiotherapy across the UK. After the initial physiotherapist review, participants were instructed to adhere to a self-directed home exercise based protocol, which focused on unloaded bending of the knee to promote range of motion and using the weight of the limb to strengthen the quadriceps muscle (with a stationary knee). Eighteen self-directed sessions were performed over the six weeks (three times weekly).

[..] We chose the patient reported Oxford knee score as the primary outcome because it specifically measures the outcomes of knee arthroplasty and is routinely used in the UK. Scores range from 0 (worst) to 48 (best), with 4 points indicating a minimum clinically important difference.

[..] Overall, 4264 patients were screened for eligibility of whom 334 were randomised. Most of the screened patients (n=2968, 69.6%) were not eligible for the study, enabling the rehabilitation intervention to be targeted to those defined as at risk of poor outcomes.

[..] In the intention-to-treat analysis, the adjusted mean between group difference in Oxford knee score at one year was 1.91 (95% confidence interval −0.18 to 3.99) points favouring the therapist led group (P=0.07). The result was similar in the per protocol analysis (2.02, −0.15 to 4.18) points, P=0.07).

[..] Consensus as to the best way to deliver rehabilitation after total knee arthroplasty is lacking. Specific protocols are strongly entrenched at individual physiotherapy departments despite the wider efficacy of postoperative physiotherapy being poorly established. This uncertainty about effectiveness of physiotherapy makes it difficult for patients, commissioning organisations, and healthcare providers to determine the best way to deliver physiotherapy after total knee arthroplasty and the correct level and mechanism of funding for such services.

Full article, Hamilton DF, Beard DJ, Barker KL et al. BMJ 2020.10.13