Primary Knee Symposium: Biomechanical Considerations in the Knee

TKR Survivorship: What Does the Data Say? – Michael Manley, PhD

Dr. Manley took a close look at survivorship data in a subset of the Medicare population. PSlide A Survivorship for TKR is superior then for THR in the CMS United States database. PSlide B He segmented the data by surgeon/hospital volume and OR time then conducted a complication, revision, and re-revision analysis. (Overall, there were 72,913 primary TKA with 1,599 subsequent revisions).¹

The data showed that, with regard to hospital volume, there was a significantly higher revision rate at lower volume (£ 25) hospitals than higher volume (although there was no significant difference among hospitals that performed 26-100 and those that performed more than 200). PSlide C With regard to surgeon volume, there was no significant difference in revision rates between low and high volume surgeons. PSlide D

Dr. Manley than looked for possible correlations between anesthesia time and revision rates. Anesthesia time has reduced over the last years for both TKR and THR. PSlide E He found that average anesthesia times (120-240min) were associated with lower revision rates than the very shortest and very longest procedures. PSlide F In addition, higher surgeon volume was associated with shorter anesthesia time, and higher hospital volume was associated with shorter anesthesia time.

The data showed that revision risk is greater for the revision cohort than for the primary cohort. PSlide G Comorbidities and younger age increased revision risk for the primary cohort. In addition, males have a greater revision risk for knees than females.

For complications, at 180 days post surgery Deep Venous Thrombosis (DVT) was the most common complication for the primary cohort PSlide H and re-revision for the Revision cohort. PSlide I

Overall conclusions drawn from the data analysis are summarized in PSlide J.