# 3D-Printed Patient-Specific Instrumentation Versus Conventional Techniques in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

## TL;DR

3D-printed patient-specific tools for knee replacement surgery improve alignment and reduce blood loss compared to traditional methods, but more research is needed.

## Contribution

This study provides a meta-analysis comparing 3D-printed patient-specific instrumentation with conventional techniques in total knee arthroplasty.

## Key findings

- 3D-printed PSI significantly reduces hip-knee-ankle alignment outliers.
- PSI improves overall alignment accuracy and decreases intraoperative blood loss.
- No significant difference in surgical time or complication rates was observed.

## Abstract

3D-printed patient-specific instrumentation (PSI) in total knee arthroplasty (TKA) has been proposed to improve surgical precision and outcomes compared to conventional instrumentation (CI), but its clinical benefits remain uncertain. We conducted a systematic review and meta-analysis of 14 comparative studies, including 2,704 TKA procedures, evaluating surgical time, intraoperative blood loss, alignment accuracy, and malalignment rates. Databases searched included PubMed, Embase, Scopus, Web of Science, and Cochrane CENTRAL. Random-effects meta-analysis demonstrated that PSI significantly reduced hip-knee-ankle alignment outliers (OR = 0.30, p < 0.00001), improved overall alignment accuracy (standardized mean difference (SMD) = -0.27, p = 0.02), and decreased intraoperative blood loss (SMD = -1.05, p = 0.009), while no significant difference was observed in surgical time (SMD = -0.78, p = 0.17), despite high heterogeneity. Complication rates were similar between groups. These findings indicate that 3D-printed PSI enhances alignment precision and reduces blood loss in TKA without increasing perioperative risk, highlighting its potential utility in complex cases or high-volume surgical settings. However, these results should be interpreted with caution given the predominance of observational studies and generally short follow-up durations among the included literature. Further high-quality trials are warranted to clarify its long-term clinical, functional, and economic impact.