TKR vs UKR

TKR vs UKR

TOPKAT Trial – 5-Year Outcomes (Beard et al., 2019)

Total vs Partial Knee Replacement for Medial Knee Arthritis

🔗 Beard DJ, et al. The clinical and cost-effectiveness of total versus partial knee replacement in patients with medial compartment osteoarthritis (TOPKAT): 5-year outcomes of a randomised controlled trial. Lancet. 2019 Aug 31;394(10200):746-756. doi: 10.1016/S0140-6736(19)31281-4. Epub 2019 Jul 17. PMID: 31326135; PMCID: PMC6727069.

Key Points

• This large UK randomised controlled trial compared total knee replacement (TKR) with partial knee replacement (PKR)
• Both operations led to major improvements in pain and function
• There was no meaningful difference in overall outcomes at 5 years
• Partial knee replacement was more cost-effective and had slightly better patient-reported outcomes
• Complication rates were lower with partial knee replacement
• This is the highest-quality evidence guiding the choice between these two operations

What was studied?

This was a large multicentre UK randomised controlled trial involving:

• 528 patients across 27 centres
• Patients with arthritis affecting only the inner (medial) part of the knee

Patients were randomly assigned to:

• Total knee replacement (replacing the whole joint)
• Partial knee replacement (replacing only the damaged compartment)

The main outcome measured was the Oxford Knee Score (OKS) at 5 years.

What were the results?

Improvement in pain and function

Both groups improved significantly:

• Average improvement of more than 18 points on the Oxford Knee Score
• This represents a large and meaningful improvement in symptoms

At 5 years:

• PKR: mean OKS ~38
• TKR: mean OKS ~37
• Difference: not statistically or clinically significant

Patient experience

Patients undergoing partial knee replacement reported:

• Slightly better perception of improvement
• Higher likelihood of saying their knee felt better than before surgery
• Greater likelihood of choosing the operation again

For example:

• 95% of PKR patients felt their knee was better vs 90% in TKR
• 91% would choose surgery again vs 84% in TKR

Complications and re-operations

• Complications were lower with partial knee replacement (20% vs 27%)
• Rates of re-operation and revision were similar between groups

This is important as registry data had previously suggested higher revision rates for partial knee replacement, which was not seen in this trial

Recovery and hospital stay

• Shorter hospital stay with partial knee replacement
  • PKR: ~3.2 days
  • TKR: ~4.3 days

Cost-effectiveness

Partial knee replacement was:

• Less expensive (around £900 cheaper per patient)
• More effective overall in quality-adjusted life years
• Probability of being the most cost-effective option: >99%

Why is this important?

This is the largest and most robust randomised trial comparing partial and total knee replacement.

It showed that:

• Both operations work very well
• Partial knee replacement offers similar outcomes with some advantages
• Real-world registry data may overestimate revision risk in partial knee replacement

What does this mean for patients?

For patients with arthritis affecting only one part of the knee:

• Both total and partial knee replacement are excellent options
• Partial knee replacement may offer:
  • Faster recovery
  • More natural knee feeling
  • Lower complication rates
  • Lower overall cost

However:

• Not all patients are suitable for partial knee replacement
• Surgical expertise and correct patient selection are key

How this relates to my practice

This study was led by Professor David Beard, with whom I collaborate on research, and forms a key part of the evidence base guiding knee replacement decisions in the UK.

In my practice, I use these findings to:

• Carefully assess whether a patient is suitable for partial knee replacement
• Offer personalised treatment based on anatomy, symptoms, and activity level
• Ensure patients understand the benefits and limitations of each option