# 3D guided large osteochondral allograft reconstructions for post-traumatic osteoarticular bone loss of the knee: a technical note

## TL;DR

This paper introduces a 3D-assisted surgical planning method for knee allograft reconstruction, showing accurate placement and improved patient outcomes.

## Contribution

The paper presents a novel technical approach using 3D virtual planning for precise allograft reconstruction in complex knee bone loss cases.

## Key findings

- 3D-assisted planning achieved submillimeter accuracy in graft placement with minimal translational and rotational deviations.
- Patient-reported functional outcomes improved significantly over one year post-surgery.
- The method enabled anatomical restoration and successful allograft integration in two complex knee cases.

## Abstract

Post-traumatic osteoarticular bone loss of the knee remains challenging to treat. Allograft reconstruction can yield favourable outcomes, and 3D virtual surgical planning may further improve results by enabling precise templating, optimal graft selection, and accurate fixation. This study aimed to introduce and evaluate 3D-assisted planning for knee allograft reconstruction.

In two patients with severe post-traumatic knee osteoarticular bone loss—one in the medial distal femur and one in the proximal tibial plateau—3D-assisted resection and allograft reconstruction were performed. An allograft was matched to the affected condyle, after which cutting planes were defined and patient-specific guides were designed. Postoperative CT-scans were obtained to assess accuracy, and patient-reported outcomes were evaluated with the Lower Extremity Functional scale(LEFS) questionnaire.

Both surgical procedures went uneventful. In the lateral plateau case, 3D analysis of the postoperative CT scan showed a maximum translational deviation from the plan of 2.2 mm and a maximum rotational deviation of 3.2°. In the medial distal femur case, postoperative 3D assessment revealed a maximum translational deviation of 2.5 mm and a maximum rotational error of 3.5°. Functional outcomes (> 1 year postop) were favourable, with LEFS scores improving from 29/100 to 78/100 in the lateral plateau case and from 22/100 to 81/100 in the medial distal femur case.

In conclusion, this technical note demonstrates the feasibility and accuracy of 3D-assisted planning for knee allograft reconstruction. The approach enables precise allograft placement and anatomical restoration.