The TRIO-physio study is looking at how well patients with osteoarthritis recover after knee replacement surgery (also known as Total Knee Arthroplasty (TKA)). Currently around 20% of patients are not satisfied after TKA. This project will look to find out if the research team can identify patients who will not recover well at an earlier stage, so that these patients can be helped sooner.

The study will try to determine if doing intense physiotherapy with patients who are not doing well at the first review (6 weeks after their operation) can improve how well they have recovered at one year.

The study is a randomised controlled trial comparing the effect of intensive physiotherapy compared to current standard of care therapy, targeted to patients performing poorly at 6 weeks following total knee replacement.

All patients will be made aware of the study pre-operatively at the recruiting centres. Prior to surgery they will complete the routine pre-operative outcome assessment questionnaires (Oxford Knee Score and EQ-5D) as part of the national PROMS program and then undergo the local standard total knee replacement and immediate post-operative care pathway.

All patients will be routinely reviewed 6 weeks post-operatively by the usual clinical teams. At this review the Oxford Knee Score will again be assessed. Those patients who report a score of 26 or less (on the 0-48 OKS scoring system), which is defined as poor by the Kalairajah classification (Kalairajah, 2005), will be approached to consent. If consent is given and the patient is eligible to enter the trial, randomisation into one of the following groups will occur: to standard care (encompassing a one off physiotherapy review, 6 weeks of home exercise prescription and final review) or to an interventional arm, where 18 sessions of structured physiotherapy will be administered over a 6 week period, where 6 of these sessions will be 'contact sessions' performed under the supervision of the physiotherapist.

All trial participants will be reviewed immediately post intervention (i.e. at 14 weeks post operation) and then by postal questionnaire at 26 and 52 weeks post-operation.

Inclusion Criteria:

• Undergoing primary total knee arthroplasty for osteoarthritis.
• Defined poor outcome (Oxford Knee Score less than or equal to 26) at first post-op review (6 weeks).
• Patients are able to consent and willing to comply with the study protocol

Exclusion Criteria:

• Patients undergoing revision knee arthroplasty or fully constrained knee arthroplasty
• Knee replacement for a diagnosis other than osteoarthritis
• Patients unable to attend the study physiotherapy intervention centre
• Procedures done purely for pain relief (such as for patients with no walking capacity)
• Patients already receiving ongoing structured post-operative exercise rehabilitation