Abstract
Background: Aseptic loosening (AL) is among the major reasons for revision of failed primary unicompartmental knee arthroplasty (UKA). There is an ongoing temporal increase in the use of UKA with a resultant increase in the revision burden. We aimed to evaluate the incidence of, temporal trends and risk factors for AL.
Methods: Longitudinal studies reporting the incidence of AL following primary UKA were sought from MEDLINE, Embase, Web of Science and Cochrane Library up to 6th April 2020. Incidence and relative risks (RR) (with 95% confidence intervals) were calculated.
Results: We identified 62 studies for inclusion. Overall, 96,294 primary UKA procedures accounting for 1752 AL cases were included. AL incidence ranged from 0.00% to 22.70% over a 7.7 year weighted mean follow-up. The pooled random effects incidence (95% CI) was 1.77% (1.34-2.25) in the same follow-up period. The annual rate of AL was 0.10% (0.02-0.22). AL incidence increased with length of follow-up, but there was a temporal decrease from the 1970s onwards. Tibial loosening was more common than femoral component loosening: incidence (95% CI) of 1.63% (0.96-2.44) and 0.58% (0.20-1.09) respectively over a weighted follow-up of 6.6 years. Fixed bearing implant design and cemented fixation were both associated with increased AL risk, whereas robotic-assisted surgery was associated with decreased risk.
Conclusion: The overall incidence of AL following primary UKA is primarily driven by tibial component loosening and there is a temporal decline in rates. The use of mobile bearing, uncemented implants inserted with robotic assisted surgery may reduce the risk of AL.
Methods: Longitudinal studies reporting the incidence of AL following primary UKA were sought from MEDLINE, Embase, Web of Science and Cochrane Library up to 6th April 2020. Incidence and relative risks (RR) (with 95% confidence intervals) were calculated.
Results: We identified 62 studies for inclusion. Overall, 96,294 primary UKA procedures accounting for 1752 AL cases were included. AL incidence ranged from 0.00% to 22.70% over a 7.7 year weighted mean follow-up. The pooled random effects incidence (95% CI) was 1.77% (1.34-2.25) in the same follow-up period. The annual rate of AL was 0.10% (0.02-0.22). AL incidence increased with length of follow-up, but there was a temporal decrease from the 1970s onwards. Tibial loosening was more common than femoral component loosening: incidence (95% CI) of 1.63% (0.96-2.44) and 0.58% (0.20-1.09) respectively over a weighted follow-up of 6.6 years. Fixed bearing implant design and cemented fixation were both associated with increased AL risk, whereas robotic-assisted surgery was associated with decreased risk.
Conclusion: The overall incidence of AL following primary UKA is primarily driven by tibial component loosening and there is a temporal decline in rates. The use of mobile bearing, uncemented implants inserted with robotic assisted surgery may reduce the risk of AL.
| Original language | English |
|---|---|
| Pages (from-to) | 28-38 |
| Number of pages | 11 |
| Journal | The Knee |
| Volume | 31 |
| Early online date | 7 Jun 2021 |
| DOIs | |
| Publication status | Published - 1 Aug 2021 |
Bibliographical note
Funding Information:This study was funded by the NIHR Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol (BRC-1215-20011). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.
Publisher Copyright:
© 2021 Elsevier B.V.
Keywords
- UKA
- aseptic loosening
- UKR
- unicondylar knee arthroplasty
- unicondylar knee replacement
- metaanalysis