Benchmarking total knee replacement constructs using noninferiority analysis: the New Zealand joint registry study

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Medical device performance analysis

Background:

• Total knee replacement (TKR) is a common procedure.
• Assessing the comparative performance of TKR prostheses is crucial for patient outcomes.
• Variability in implant performance can impact revision rates and patient satisfaction.

Purpose of the Study:

• To compare the relative performance of different total knee replacement (TKR) constructs.
• To identify variability in the performance of commonly used TKR prostheses within the New Zealand Joint Registry (NZJR).
• To utilize a noninferiority analysis to benchmark TKR construct effectiveness.

Main Methods:

• A noninferiority analysis was conducted on primary TKR procedures registered in the NZJR from January 1999 to June 2020.
• All-cause revision rates for TKR constructs were estimated using the 1-Kaplan Meier survival function.
• The performance of each construct was compared against the best-performing contemporary benchmark.

Main Results:

• Out of 110,183 TKR procedures, 25 constructs with over 500 procedures at risk at 3 years showed significant inferiority.
• At 3 years, 5 constructs were at least 20% inferior, with one being over 100% inferior in relative risk.
• At 10 years, 5 out of 14 constructs with over 500 procedures at risk were at least 20% inferior, with 2 over 100% inferior.

Conclusions:

• Significant variability exists in the performance of total knee replacement constructs.
• At all time points analyzed, over 25% of TKR constructs performed at least 20% worse than the leading construct.
• These findings provide valuable data for patients, clinicians, and funders when selecting TKR prostheses.