Rotating platform versus fixed bearing total knee arthroplasty at mid-term follow-up.
BACKGROUND
Rotating platform posterior stabilized (RP) total knee arthroplasty (TKA) was initially developed in part to decrease polyethylene wear and to improve patellar tracking. There have been limited studies evaluating the longevity and causes of reoperation or revision for this implant. The following study compares mid-term survival rates and causes for reoperation between fixed bearing (FB) TKAs.


METHODS
We identified 11,416 patients who underwent a primary posterior stabilized TKA between 2001 and 2013. This group was stratified to include patients with a RP (n=926) and FB (n=10,490) TKA design. Kaplan-Meier survival rates for each complication that led to reoperation were determined at five- and 10-years. Univariate hazard ratios were determined for the most common causes for reoperation and overall implant survival rates. A multivariate analysis was performed to account for the age, gender and preoperative diagnosis discrepancy between groups.


RESULTS
The reoperation data demonstrated statistically increased all-cause reoperation rate (p=<0.001) and reoperation rate for stiffness in the RP group (p=0.001). After adjusting for demographic variables we noted no statistically significant differences in reoperation rate and reoperation for stiffness. Additionally, a statistically significant decrease was noted in all-cause revision (p=0.024) and revision for aseptic loosening or osteolysis in the RP group (p=0.029).


CONCLUSIONS
After adjusting for patient demographic differences, we noted a statistically significant decrease in the overall revision and revision for aseptic loosening or osteolysis rates in the RP group.
Mayo Clinic, Department of Orthopedic Surgery, 200 First Street SW, Rochester, MN 55905, United States. Electronic address: johrmart@gmail.com.
J Ryan
JR
Martin
Mayo Clinic, Department of Orthopedic Surgery, 200 First Street SW, Rochester, MN 55905, United States. Electronic address: Beahrs.Taylor@mayo.edu.
Taylor R
TR
Beahrs
Mayo Clinic, Department of Orthopedic Surgery, 200 First Street SW, Rochester, MN 55905, United States. Electronic address: kfehring@gmail.com.
Keith A
KA
Fehring
Mayo Clinic, Department of Orthopedic Surgery, 200 First Street SW, Rochester, MN 55905, United States. Electronic address: trousdale.robert@mayo.edu.
Robert T
RT
Trousdale
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D013997:Time Factors; D016896:Treatment Outcome
Aseptic loosening; Osteolysis; Revision; Rotating platform; TKA