3D-printed personalized osteotomy guides affect mid- to long-term efficacy of unicompartmental knee arthroplasty: mechanisms, evidence, and prospects

Abstract

BACKGROUND: Unicompartmental knee arthroplasty is a commonly used surgical method for treating localized knee osteoarthritis, and its success relies on precise osteotomy and prosthesis positioning. Traditional techniques depend on the surgeon's experience and two-dimensional imaging, which makes it difficult to completely avoid alignment errors; these errors may affect the prosthesis survival rate and long-term efficacy. OBJECTIVE: To systematically summarize the factors determining the mid- and long-term efficacy of unicompartmental knee arthroplasty, analyze the technical principles of personalized osteotomy guides based on 3D printing combined with digital design, artificial intelligence planning, and physical manufacturing, providing evidence to improve surgical accuracy. Furthermore, this article elaborates on enhancing surgical precision by optimizing biomechanics and reducing abnormal prosthesis wear, thereby improving prosthesis survival rate, maintaining joint function, and reducing the risk of adverse reactions. METHODS: Relevant literature published in PubMed and China National Knowledge Infrastructure was searched, using Chinese and English search terms including “3D printing, unicompartmental knee arthroplasty, patient-specific instrumentation, mid-term, long-term, outcome.” After screening, a total of 65 articles were included for analysis. RESULTS AND CONCLUSION: ①3D-printed personalized osteotomy guides, created through CT scanning, three-dimensional reconstruction, and 3D printing, significantly improve the surgical accuracy of unicompartmental knee arthroplasty. ②Compared with traditional surgery, 3D-printed personalized osteotomy guides reduce coronal and sagittal prosthesis placement errors, improve lower limb alignment, increase prosthesis survival rate, and reduce mid- to long-term adverse reactions such as aseptic loosening. However, there are controversies including suboptimal tibial rotational alignment, increased costs, and no significant advantage in short-term functional scores. ③Compared with robotic assistance, 3D-printed personalized osteotomy guides are slightly less accurate but have a shorter learning curve and lower cost. Currently, there is a lack of long-term randomized controlled evidence in this field, and the technique relies on high-quality imaging data with a long preoperative preparation period. ④By analyzing existing research on personalized osteotomy guides, this article summarizes the role of this technology in improving surgical precision, while also discussing its current status and limitations in terms of cost-effectiveness, clinical workflow integration, and insufficient high-quality evidence. ⑤To promote the widespread application of personalized guides in precise unicompartmental knee arthroplasty treatment, future efforts should include multicenter long-term randomized controlled trials, integration of artificial intelligence and intraoperative dynamic navigation, and the establishment of predictive models based on real-world data, thereby providing a more solid theoretical basis for its clinical application.

1. Introduction

Osteoarthritis is a common chronic degenerative joint disease, with clinical manifestations including joint pain, stiffness, swelling, limited mobility, and deformity. It commonly affects the knee, hip, ankle, hand, and spinal joints. Among various types of osteoarthritis, knee osteoarthritis has a high prevalence in China, affecting 35%-60% of people over 60 years old. Due to anatomical factors such as the natural varus alignment of the lower limb, the medial compartment bears 60%-80% of the load, and the medial meniscus has limited mobility, leading to a higher incidence of anteromedial osteoarthritis.

For end-stage anteromedial osteoarthritis, unicompartmental knee arthroplasty (UKA) has become an ideal ultimate treatment in the stepwise approach, as it preserves the anterior and posterior cruciate ligaments and the natural kinematics of the knee, offering advantages such as less trauma, reduced blood loss, faster recovery, less pain, and fewer adverse reactions. However, this procedure demands high precision; accurate prosthesis placement and restoration of lower limb alignment directly determine mid- and long-term outcomes. Studies have shown that even minor alignment deviations (e.g., coronal varus/valgus >3°) can significantly increase the risk of polyethylene liner wear, aseptic loosening of the prosthesis, and degeneration of the contralateral compartment, potentially leading to early revision.

Traditional UKA relies on the surgeon's experience, which limits precision and introduces variability. With the advancement of personalized 3D-printed osteotomy guides and robotic-assisted surgery, China's digital precision surgery has entered a new stage. However, robotic systems are costly and technically complex, whereas 3D-printed personalized osteotomy guides offer a relatively economical investment, simplified procedures, and high compatibility with traditional surgical techniques, demonstrating unique application prospects in clinical promotion.