2025 ISAKOS Biennial Congress ePoster
Use of Patient-Specific 3D-Printed Intraoperative Spacers in Complex Revision Total Knee Arthroplasty. Surgical Technique and Preliminary Results.
Giulio Vittone, MD ITALY
Marcello Motta, MD, Brescia ITALY
Marco Adriani, MD, Brescia, Brescia ITALY
Alberto Guizzi ITALY
Alessandro Colosio, MD, Brescia ITALY
Giuseppe Milano, Prof., Brescia, BS ITALY
University of Brescia, Brescia, BS, ITALY
FDA Status Not Applicable
Summary
The purpose of this work is to describe a new surgical technique based on 3D-analysis of bone defects through CT-scans of both lower limbs and subsequent creation of 3D-printed anatomic spacers to guide placement of the prosthetic components in revisione total knee arthroplasty.
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Abstract
Purpose
To describe a new surgical technique based on the three-dimensional (3D) analysis of bone defects through computed tomography (CT) scans of both lower limbs and subsequent creation of 3D-printed anatomic spacers to guide placement of the prosthetic components and to analyze the preliminary clinical and radiographic results of this technique in patients who underwent two-stage RTKA for the treatment of PPJI.
Methods
A retrospective study was conducted on 10 consecutive patients (8 males and 2 females; mean age: 72 ± 8.1 years) affected by knee PPJI and treated with two-stage RTKA. After the first stage, all the patients underwent a full-leg bilateral CT scan. Dedicated software was used to process CT images and to develop a 3D virtual reconstruction of the lower limbs. Bone defects on the explanted knee were estimated through superimposition and mirroring of the contralateral healthy knee. 3D-printed spacers reproducing the femoral and tibial bone defects were used intraoperatively to determine joint line height (JLH) and prosthetic component rotation. At follow-up, all the patients underwent full-length weight-bearing radiographs to evaluate coronal and sagittal knee alignment. The hip-knee-ankle angle (HKA), the medial proximal tibial angle concerning the mechanical axis (mMPTA), and the lateral distal femoral angle concerning the mechanical axis (mLDFA), and the posterior tibial slope angle (PTSA) were measured. Additionally, the variation in the femoral joint line height (∆ FJLH) after the surgery compared to the contralateral side was assessed. The position of the femoral joint line was defined as the distance between the adductor tubercle and the tangent to the femoral condyles on the AP X-ray. The range of motion (ROM) of the operated knee was also evaluated. Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Forgotten Joint Score-12 (FJS-12) were also administered.
Results
The mean follow-up was 13.7 ± 1.5 months. No major complications were reported at follow-up. On weight-bearing radiographs, we found an average HKA of 179.9° ± 2.8°, an average mMPTA of 90.7° ± 1.2°, an average mLDFA of 90.3° ± 1.9°, and an average PTSA of 1.1° ± 0.7°. The position of the femoral joint line in comparison to the contralateral side was 2 mm ± 2.1 mm proximal.
All patients regained full knee extension and mean postoperative flexion of 108.9° ± 9.6°. Patient-reported outcomes showed a mean KSS-Knee Score of 85.8 ± 9.7, mean KSS-Function Score of 52 ± 22.3, mean KOOS-JR of 78.2 ± 11.2, and mean FJS-12 of 70.1 ± 17.8.
Conclusions
Intraoperative use of 3D-printed spacers resembling the bone defects and realized by mirroring the contralateral healthy knee allows an accurate sizing and placement of the prosthetic components and facilitates restoration of the joint line height and limb alignment in complex RTKA.