In 1989 Kozinn and Scott published what were at the time the ideal indications for Partial Knee Replacement1. According to their criteria, only 5% of patients were candidates for PKR. This may partly explain why there is low utilisation of PKA today, with it only being used for 8%2,3 of knee replacements worldwide.

An intact, functioning ACL plays a critical role in determining candidacy for PKA.

  • One study showed that 47.6% of all knee replacement patients are candidates for PKA4
  • In a study of consecutive TKAs by Lee et al.5 61% of patients were found to have an intact ACL
  • In a more recent presentation, Berend, et al.6 found 53% of knee replacement candidates had a normal, intact ACL

Utilisation: closing the revision gap

The revision gap between PKA and TKA reported in national joint registries has been reduced with increased utilisation of PKRs:

  • Tregonning, et al in a study reviewing the New Zealand Joint Registry found that surgeons performing at least 12 PKRs per year are found to have a decreased revision rate7
  • Liddle, AD. et al8 found in the National Joint Registry for England and Wales that surgeons utilising PKA for at least 20% of their annual knee replacements experienced a dramatic decrease in their revision rate

What's more, with research showing that up to 61% of patients5 could be candidates for PKA, the optimal usage of performing at least 12 partial knee replacements per year7 can easily be achieved.

  1. Kozinn, S. C., & Scott, R.. Unicondylar knee arthroplasty. The Journal of Bone & Joint Surgery, 71(1), 145-150. 1989.
  2. European Millennium Report Study 2013.
  3. US Millennium Study 2013.
  4. Willis-Owen, et al. Unicondylar knee arthroplasty in the UK National Health Service: An analysis of candidacy, outcome and cost efficacy. ScienceDirect. The Knee 16. 473–478. 2009
  5. Lee, C. et al. Evaluation of the Anterior Cruciate Ligament Integrity and Degenerative Arthritic Patterns in Patients Undergoing Total Knee Arthroplasty. The Journal of Arthroplasty Vol. 20 No. 1 2005
  6. Berend, K. et al. Does the Status of the ACL at the Time of Primary Total Knee Arthroplasty Predict Early Outcomes? AAHKS Poster Presentation 2014.
  7. Tregonning, R et al. Early Failure Of The Oxford Phase 3 Cemented Medial Uni-Compartmental Knee Joint Arthroplasty: An Audit Of The Nz Joint Registry Over Six Years. The Bone & Joint Journal. 2014, 96-B (SUPP 19)
  8. Liddle, AD et al. Optimal usage of Unicompartmental Knee Replacement: A study of 41,986 patients from the National Joint Registry for England and Wales. ISAR Annual Meeting 2013