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.
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
3,500
Knee Function Score at 1 Year After Surgery
The KSS ranges from 0 to 100, with higher scores indicating better knee function.
Time frame: 1 year after surgery
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.
Time frame: Perioperative through 5 years after surgery
Length of Postoperative Hospital Stay
Length of hospital stay after primary unilateral total knee arthroplasty.
Time frame: 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).
Time frame: 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).
Time frame: 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.
Time frame: 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.
Time frame: From hospitalization through 5 years after surgery
Indirect Costs
Indirect costs associated with primary unilateral total knee arthroplasty, including productivity loss where available.
Time frame: 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.
Time frame: At end of analysis
Postoperative Adverse Events
All postoperative adverse events recorded during the study follow-up period.
Time frame: From surgery through 5 years after surgery
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