# Is still effective massive allograft reconstruction in parosteal osteosarcoma of the distal femur? Review of the literature and advantages of newer technologies

## TL;DR

This paper reviews treatment options for a rare bone cancer in the thigh and highlights benefits of new 3D-printed tools for surgery.

## Contribution

The paper introduces the use of custom 3D-printed cutting guides for improved surgical outcomes in parosteal osteosarcoma.

## Key findings

- Biological grafts are still the most common reconstruction method after tumor resection.
- 3D-printed cutting guides improve surgical precision and reduce procedure time.
- Functional outcomes remain excellent with a high MSTS score of 86%.

## Abstract

Parosteal Osteosarcoma is a well-differentiated, low-grade bone sarcoma. It most commonly occurs in the third decade of life, usually in the distal femur. This study aims to perform a literature review about the types of reconstructions reported and to analyze the results of an updated technique of resection using custom-made 3D-printed cutting guides.

We perform a systematic literature review about parosteal osteosarcoma, evaluating treatments, margins, local recurrence, complications, and functional results when available. We also report a case treated in our Center with a revisited technique introducing custom-made 3D-printed cutting guides.

We analyzed 12 studies with a total of 151 patients. The distal femur was the most frequently reported site (81.5%). After distal femur resection, reconstruction was performed with graft in most cases (48%), followed by prosthetic reconstruction (40%). Margins were wide in 85.5% of cases. The total incidence of local recurrence was 11%. Functional results were excellent in all cases, with a mean MSTS score of 86%. In our case, with the help of the jigs, the surgical technique was relatively easy, graft fusion excellent and fast, margins wide, and functional results excellent.

In the literature, the most commonly used type of reconstruction after resection is biological with graft. Indeed, despite the increasing number of prosthetic reconstructions, the historical diaphysometaphyseal hemiresection and graft is still indicated in parosteal osteosarcoma of the distal femur. New technologies, such as the jigs we used, allow significant advantages during the procedure: reduce the resection and graft preparation time, allow a better match between components, and help to obtain safer margins, sparing as much bone as possible.