Total versus partial knee replacement in patients with medial compartment knee osteoarthritis: the TOPKAT RCT

BACKGROUND

Late-stage medial compartment knee osteoarthritis can be treated using total knee replacement or partial (unicompartmental) knee replacement. There is high variation in treatment choice and insufficient evidence to guide selection.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of partial knee replacement compared with total knee replacement in patients with medial compartment knee osteoarthritis. The findings are intended to guide surgical decision-making for patients, surgeons and health-care providers.

DESIGN

This was a randomised, multicentre, pragmatic comparative effectiveness trial that included an expertise component. The target sample size was 500 patients. A web-based randomisation system was used to allocate treatments.

SETTING

Twenty-seven NHS hospitals (68 surgeons).

PARTICIPANTS

Patients with medial compartment knee osteoarthritis.

INTERVENTIONS

The trial compared the overall management strategy of partial knee replacement treatment with total knee replacement treatment. No specified brand or subtype of implant was investigated.

MAIN OUTCOME MEASURES

The Oxford Knee Score at 5 years was the primary end point. Secondary outcomes included activity scores, global health measures, transition items, patient satisfaction (Lund Score) and complications (including reoperation, revision and composite 'failure' - defined by minimal Oxford Knee Score improvement and/or reoperation). Cost-effectiveness was also assessed.

RESULTS

A total of 528 patients were randomised (partial knee replacement, n = 264; total knee replacement, n = 264). The follow-up primary outcome response rate at 5 years was 88% and both operations had good outcomes. There was no significant difference between groups in mean Oxford Knee Score at 5 years (difference 1.04, 95% confidence interval -0.42 to 2.50). An area under the curve analysis of the Oxford Knee Score at 5 years showed benefit in favour of partial knee replacement over total knee replacement, but the difference was within the minimal clinically important difference [mean 36.6 (standard deviation 8.3) (n = 233), mean 35.1 (standard deviation 9.1) (n = 231), respectively]. Secondary outcome measures showed consistent patterns of benefit in the direction of partial knee replacement compared with total knee replacement although most differences were small and non-significant. Patient-reported improvement (transition) and reflection (would you have the operation again?) showed statistically significant superiority for partial knee replacement only, but both of these variables could be influenced by the lack of blinding. The frequency of reoperation (including revision) by treatment received was similar for both groups: 22 out of 245 for partial knee replacement and 28 out of 269 for total knee replacement patients. Revision rates at 5 years were 10 out of 245 for partial knee replacement and 8 out of 269 for total knee replacement. There were 28 'failures' of partial knee replacement and 38 'failures' of total knee replacement (as defined by composite outcome). Beyond 1 year, partial knee replacement was cost-effective compared with total knee replacement, being associated with greater health benefits (measured using quality-adjusted life-years) and lower health-care costs, reflecting lower costs of the index surgery and subsequent health-care use.

LIMITATIONS

It was not possible to blind patients in this study and there was some non-compliance with the allocated treatment interventions. Surgeons providing partial knee replacement were relatively experienced with the procedure.

CONCLUSIONS

Both total knee replacement and partial knee replacement are effective, offer similar clinical outcomes and have similar reoperation and complication rates. Some patient-reported measures of treatment approval were significantly higher for partial knee replacement than for total knee replacement. Partial knee replacement was more cost-effective (more effective and cost saving) than total knee replacement at 5 years.

FUTURE WORK

Further (10-year) follow-up is in progress to assess the longer-term stability of these findings.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN03013488 and ClinicalTrials.gov NCT01352247.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 20. See the NIHR Journals Library website for further project information.

Occupational advice to help people return to work following lower limb arthroplasty: the OPAL intervention mapping study

BACKGROUND

Hip and knee replacements are regularly carried out for patients who work. There is little evidence about these patients' needs and the factors influencing their return to work. There is a paucity of guidance to help patients return to work after surgery and a need for structured occupational advice to enable them to return to work safely and effectively.

OBJECTIVES

To develop an occupational advice intervention to support early recovery to usual activities including work that is tailored to the requirements of patients undergoing hip or knee replacements. To test the acceptability, practicality and feasibility of this intervention within current care frameworks.

DESIGN

An intervention mapping approach was used to develop the intervention. The research methods employed were rapid evidence synthesis, qualitative interviews with patients and stakeholders, a prospective cohort study, a survey of clinical practice and a modified Delphi consensus process. The developed intervention was implemented and assessed during the final feasibility stage of the intervention mapping process.

SETTING

Orthopaedic departments in NHS secondary care.

PARTICIPANTS

Patients who were in work and intending to return to work following primary elective hip or knee replacement surgery, health-care professionals and employers.

INTERVENTIONS

Occupational advice intervention.

MAIN OUTCOME MEASURES

Development of an occupational advice intervention, fidelity of the developed intervention when delivered in a clinical setting, patient and clinician perspectives of the intervention and preliminary assessments of intervention effectiveness and cost.

RESULTS

A cohort study (154 patients), 110 stakeholder interviews, a survey of practice (152 respondents) and evidence synthesis provided the necessary information to develop the intervention. The intervention included information resources, a personalised return-to-work plan and co-ordination from the health-care team to support the delivery of 13 patient and 20 staff performance objectives. To support delivery, a range of tools (e.g. occupational checklists, patient workbooks and employer information), roles (e.g. return-to-work co-ordinator) and training resources were created. Feasibility was assessed for 21 of the 26 patients recruited from three NHS trusts. Adherence to the defined performance objectives was 75% for patient performance objectives and 74% for staff performance objectives. The intervention was generally well received, although the short time frame available for implementation and concurrent research evaluation led to some confusion among patients and those delivering the intervention regarding its purpose and the roles and responsibilities of key staff.

LIMITATIONS

Implementation and uptake of the intervention was not standardised and was limited by the study time frame. Evaluation of the intervention involved a small number of patients, which limited the ability to assess it.

CONCLUSIONS

The developed occupational advice intervention supports best practice. Evaluation demonstrated good rates of adherence against defined performance objectives. However, a number of operational and implementation issues require further attention.

FUTURE WORK

The intervention warrants a randomised controlled trial to assess its clinical effectiveness and cost-effectiveness to improve rates and timing of sustained return to work after surgery. This research should include the development of a robust implementation strategy to ensure that adoption is sustained.

STUDY REGISTRATION

Current Controlled Trials ISRCTN27426982 and PROSPERO CRD42016045235.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 45. See the NIHR Journals Library website for further project information.

Effect of Timing and Duration of Statin Exposure on Risk of Hip or Knee Revision Arthroplasty: A Population-based Cohort Study

OBJECTIVES

To determine whether the timing and duration of statin exposure following total hip/knee arthroplasty (THA/TKA) influence the risk of revision arthroplasty.

METHODS

Subjects from the Clinical Practice Research Datalink, a large population-based clinical database, who had THA/TKA from 1988 to 2016, were included. Propensity score adjusted Cox regression models were used to determine the association between statin exposure and the risk of revision THA/TKA, (1) at any time, and (2) if first exposed 0-1, 1-5, or > 5 years following THA/TKA. We also investigated the effect of duration of statin exposure (< 1, 1-2, 2-3, 3-4, 4-5, > 5 yrs).

RESULTS

The study included 151,305 participants. There were 65,032 (43%) exposed to statins during followup and 3500 (2.3%) had revision arthroplasty. In a propensity score adjusted model, exposure to statins was associated with a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.75-0.90). Participants first exposed within 1 year and between 1 and 5 years following THA/TKA (vs unexposed) had a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.74-0.91 and HR 0.76, 95% CI 0.65-0.90, respectively). In relation to duration of statin therapy, participants exposed for more than 5 years in total (vs < 1 yr) had a reduced risk of revision (HR 0.74, 95% CI 0.62-0.88).

CONCLUSION

Statin therapy initiated up to 5 years following THA/TKA may reduce the risk of revision arthroplasty.

Does clinically important change in function after knee replacement guarantee good absolute function? The multicenter osteoarthritis study

OBJECTIVE

Poor functional outcomes post-knee replacement are common, but estimates of its prevalence vary, likely in part because of differences in methods used to assess function. The agreement between improvement in function and absolute good levels of function after knee replacement has not been evaluated. We evaluated the attainment of improvement in function and absolute good function after total knee replacement (TKR) and the agreement between these measures.

METHODS

Using data from The Multicenter Osteoarthritis (MOST) Study, we determined the prevalence of achieving a minimal clinically important improvement (MCII, ≥ 14.2/68 point improvement) and Patient Acceptable Symptom State (PASS, ≤ 22/68 post-TKR score) on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function subscale at least 6 months after knee replacement. We also assessed the frequency of co-occurrence of the 2 outcomes, and the prevalence according to pre-knee replacement functional status.

RESULTS

We included 228 subjects who had a knee replacement during followup (mean age 65 yrs, mean body mass index 33.4, 73% female). Seventy-one percent attained the PASS for function after knee replacement, while only 44% attained the MCII. Of the subjects who met the MCII, 93% also attained the PASS; however, of subjects who did not meet the MCII, 54% still achieved a PASS. Baseline functional status was associated with attainment of each MCII and PASS.

CONCLUSION

There was only partial overlap between attainment of a good level of function and actually improving by an acceptable amount. Subjects were more likely to attain an acceptable level of function than to achieve a clinically important amount of improvement post-knee replacement.