Comparative Study on the Medium- and Long-term Benefits of Prosthesis Selection in Total Knee Arthroplasty

This retrospective real-world study aims to compare the medium- and long-term clinical outcomes, safety, and economic benefits of different knee prosthesis brands used in primary unilateral total knee arthroplasty (TKA) at our hospital. The study will include adult patients who underwent first-time unilateral TKA between January 1, 2022 and December 31, 2025. Outcomes such as postoperative knee function, complications, length of hospital stay, quality of life, and medical costs will be evaluated. The results are expected to provide evidence to support prosthesis selection and optimize healthcare resource allocation.

Study Overview

• Status: Not yet recruiting
• Conditions: Knee Osteoarthritis; Rheumatoid Arthritis (RA)

Detailed Description

This is a single-center, retrospective, open-label, non-randomized cohort study based on real-world clinical data from the Second Affiliated Hospital of Wenzhou Medical University.

The study population will include all adult patients who underwent first-time unilateral primary total knee arthroplasty (TKA) between January 1, 2022 and December 31, 2025. Patients who underwent revision arthroplasty, simultaneous bilateral arthroplasty, concomitant arthroplasty of other joints, arthroplasty for tumor or acute trauma, or who had severely incomplete data will be excluded.

Participants will be grouped according to the prosthesis brand and model documented in the operative record. Baseline variables will include age, sex, body mass index, preoperative diagnosis, ASA classification, comorbidities, and preoperative knee function score. Surgery-related variables will include prosthesis brand and model, fixation method, operative duration, intraoperative blood loss, surgeon seniority, use of a tourniquet, and drainage duration.

The primary outcome will be knee function score at 1 year after surgery, assessed using the HSS score or KSS score. Secondary outcomes will include postoperative complications, length of hospital stay, functional recovery, quality of life, and patient-reported outcomes at different postoperative time points. Economic outcomes will include direct medical costs, direct non-medical costs, indirect costs, and cost-effectiveness analysis. Safety outcomes will include all postoperative adverse events.

The objective of this study is to comprehensively compare the medium- and long-term clinical effectiveness, safety, and economic benefits of different prosthesis brands used in TKA, and to provide evidence to support clinical prosthesis selection and healthcare resource optimization.

• Study Type: Observational
• Enrollment (Estimated): 3500

Contacts and Locations

• Study Contact: Name: Ting Li, MD, PhD; Phone Number: 86+13587876896; Email: liting1021@aliyun.com
• Study Contact Backup: Name: Xiaoyun Pan, MD, PhD; Email: xiaoyunpan@wmu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population will include adult patients who underwent first-time unilateral primary total knee arthroplasty at the Second Affiliated Hospital of Wenzhou Medical University between January 1, 2022 and December 31, 2025. Eligible patients must have complete perioperative records, prosthesis model information, cost data, and postoperative follow-up records. Patients undergoing revision arthroplasty, simultaneous bilateral arthroplasty, concomitant arthroplasty of other joints, or arthroplasty for tumor or acute trauma will be excluded.

Description

Inclusion Criteria:

• Age >= 18 years.
• Diagnosis of end-stage knee osteoarthritis, rheumatoid arthritis, or other conditions meeting the indication for TKA.
• First-time unilateral knee arthroplasty.
• Complete medical records, including perioperative records, prosthesis model records, detailed cost information, and regular postoperative follow-up records.

Exclusion Criteria:

• Revision knee arthroplasty, simultaneous bilateral arthroplasty, or concomitant arthroplasty of other joints.
• Arthroplasty performed for non-degenerative conditions such as tumour or acute trauma.
• Perioperative death or loss to follow-up.
• Severely incomplete clinical data that preclude valid analysis.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Mainstream Prosthesis Cohort; Patients who underwent first-time unilateral primary total knee arthroplasty (TKA) using established mainstream prosthesis brands during the study period.
Emerging Prosthesis Cohort; Patients who underwent first-time unilateral primary total knee arthroplasty (TKA) using emerging prosthesis brands during the study period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knee Function Score at 1 Year After Surgery	The KSS ranges from 0 to 100, with higher scores indicating better knee function.	1 year after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Complications	Complications occurring after primary unilateral total knee arthroplasty, including but not limited to infection, deep vein thrombosis, periprosthetic fracture, and prosthesis loosening. Complications will be assessed during the perioperative period and at 1 month, 3 months, 6 months, 1 year, 3 years, and 5 years after surgery.	Perioperative through 5 years after surgery
Length of Postoperative Hospital Stay	Length of hospital stay after primary unilateral total knee arthroplasty.	From surgery to hospital discharge, assessed up to 30 days
Postoperative Knee Function Score	Postoperative knee function assessed using the Hospital for Special Surgery Knee Score (HSS; range 0 to 100, with higher scores indicating better knee function) or the Knee Society Score (KSS; range 0 to 100, with higher scores indicating better outcome).	1 month, 3 months, 6 months, 3 years, and 5 years after surgery
Quality of Life and Patient-Reported Outcomes	Quality of life and patient-reported outcomes assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; total score range 0 to 96, with higher scores indicating worse pain, stiffness, and functional limitation) and/or the EuroQol 5-Dimension questionnaire (EQ-5D; higher index scores indicating better health status, depending on the value set applied).	1 month, 3 months, 6 months, 3 years, and 5 years after surgery
Direct Medical Costs	Direct medical costs associated with primary unilateral total knee arthroplasty, including total hospitalization cost, prosthesis material cost, medication cost, examination cost, surgery and anesthesia cost, bed and nursing cost, and follow-up cost.	From hospitalization through 5 years after surgery
Direct Non-Medical Costs	Direct non-medical costs associated with primary unilateral total knee arthroplasty, including caregiver expenses, transportation costs, and accommodation costs for non-local medical visits.	From hospitalization through 5 years after surgery
Indirect Costs	Indirect costs associated with primary unilateral total knee arthroplasty, including productivity loss where available.	From hospitalization through 5 years after surgery
Incremental Cost-Effectiveness Ratio	Cost-effectiveness evaluated by incremental cost-effectiveness ratio (ICER), including the cost required for each 1-point improvement in the Hospital for Special Surgery (HSS) score.	At end of analysis
Postoperative Adverse Events	All postoperative adverse events recorded during the study follow-up period.	From surgery through 5 years after surgery

Collaborators and Investigators

• Sponsor: Second Affiliated Hospital of Wenzhou Medical University

Study record dates

Study Major Dates

• Study Start (Estimated): May 31, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2030

Study Registration Dates

• First Submitted: April 10, 2026
• First Submitted That Met QC Criteria: April 20, 2026
• First Posted (Actual): April 28, 2026

Study Record Updates

• Last Update Posted (Actual): April 28, 2026
• Last Update Submitted That Met QC Criteria: April 20, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Total Knee Arthroplasty; Cost-Effectiveness; TKA; Real-World Study; Prosthesis Selection
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases; Osteoarthritis; Skin and Connective Tissue Diseases; Osteoarthritis, Knee; Arthritis, Rheumatoid
• Other Study ID Numbers: SAHoWMU-CR2026-08-208

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared publicly. The study uses retrospective hospital medical record data, and data sharing is limited by institutional regulations, ethics requirements, and the need to protect participant confidentiality.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No