3D-Printed Patient-Specific Instruments-Combined AI Virtual Preoperative Planning-Assisted Medial Fixed-Bearing Unicompartmental Knee Arthroplasty

Summary

Here, we present a protocol to enhance the precision of fixed-bearing unicompartmental knee arthroplasty. It uses a digital workflow, combining 3D-printed patient-specific instruments with preoperative simulation to improve alignment accuracy, increase surgical safety, and enable personalized, reproducible outcomes.

Abstract

Unicompartmental knee arthroplasty (UKA) is widely recognized as an effective treatment for advanced knee osteoarthritis. However, its dependency on surgical experience and two-dimensional (2D) radiographs introduces significant challenges for less-experienced surgeons and for patients with femoral or tibial bone deformities. To enhance surgical precision and reduce prosthesis malposition-related complications, our team integrated three-dimensional (3D) printing technology for patient-specific instrumentation (PSI) with artificial intelligence (AI)-based preoperative simulation planning, thereby addressing the limitations of traditional approaches. This study presents a comprehensive digital workflow for fixed-bearing UKA that aims to achieve precise prosthetic alignment, improve surgical efficiency and safety, reduce operative time, and enable personalized prosthesis positioning with consistent and reproducible outcomes. The protocol consists of five critical steps: 1. Strict patient selection based on fixed-bearing UKA indications; 2. Comprehensive imaging acquisition, including CT scans of the affected knee, anteroposterior and lateral radiographs, and full-length weight-bearing X-rays in DICOM format; 3. AI-assisted preoperative planning with detailed surgical simulation reports; 4. Fabrication of customized 3D-printed cutting guides; 5. Precise osteotomy execution with intraoperative verification. By implementing this standardized digital approach, we demonstrate how integrating AI and 3D printing can optimize UKA outcomes through enhanced reproducibility, accuracy, and patient-specific customization.

Introduction

In recent years, the deep integration of digital technologies with orthopedic science has driven a paradigm shift in clinical practice-transitioning from traditional empirical and generalized methods to precision-based, personalized, and fully digital diagnostic and therapeutic strategies¹. Within this transformative landscape, 3D printing technology, as a flagship application of digital innovation, has emerged as a pivotal enabler for achieving patient-specific customization and highly precise surgical interventions in diverse orthopedic procedures^2,3. Osteoarthritis (OA), recognized a....

Protocol

This research received ethical approval from the First Hospital of Hebei Medical University Research Ethics Committee. Informed consent was obtained from all individual participants included in the study.

1. Patient selection and preoperative imaging

1. Select patients with anteromedial compartment osteoarthritis or medial femoral condyle osteonecrosis.
2. Confirm an intact anterior cruciate ligament (ACL), competent medial collateral ligament (MCL), and lateral compartment cartilage with Outerbridge grade ≤ II changes.
3. Exclude patients with inflammatory arthritis, varus deformity varus deformity >15°....

Results

A 69-year-old male patient presented with bilateral knee osteoarthritis, who had previously undergone mobile-bearing unicompartmental knee arthroplasty on the right side two years ago with satisfactory postoperative recovery. Due to an intramedullary nailing procedure performed for femoral shaft fracture on the left knee two decades ago, conventional surgical instrumentation could not be properly inserted owing to the altered femoral medullary canal anatomy, thereby posing significant ris.......

Discussion

The successful implementation of this digital UKA protocol hinges on several critical steps. First, high-quality, thin-slice (≤1.0 mm) CT data acquisition is paramount, as the fidelity of the subsequent 3D bone models and the precision of the PSI guides are directly dependent on it^8,12. Second, the AI-guided virtual planning stage is crucial for determining patient-specific alignment. This involves accurately identifying anatomical axes and landmarks (e.g.,.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Creo Parametric 8.0.0.0	PTC	https://www.ptc.com/ en/products/creo	Surgical simulation guide output
3D-Printed Patient-Specific Instruments	Sikon Medical Co., Ltd. China	D250610	Anatomic Conformity & Precision Positioning; Optimized Limb Alignment;Surgical Efficiency; Minimally Invasive Approach?Enhanced Reproducibility
Femoral Component	Beijing Leadcom Biomedical Co., Ltd.	A5101-05lM	Resurfaces the arthritic femoral condyle (medial/lateral).
Mimics Research 21.0	Materialise	https://www.materialise. com/en/software/mimics-research-suite	image processing
Polyethylene Insert	Beijing Leadcom Biomedical Co., Ltd.	A5301-0410	Acts as an articulating surface between femoral and tibial components
Tibial Componen	Beijing Leadcom Biomedical Co., Ltd.	A5201-04LM	Replaces the worn tibial plateau and provides a base for  the polyethylene insert.