# The customized prosthesis for lateral unicompartmental knee arthroplasty in the treatment of malunion of a Hoffa fracture of the distal femur: A case report

## TL;DR

A customized knee implant helped treat a rare case of a mishealed Hoffa fracture, restoring function and reducing pain in a patient.

## Contribution

A novel customized lateral unicompartmental knee arthroplasty approach for treating malunited Hoffa fractures is presented.

## Key findings

- Customized UKA restored alignment and resolved fracture gaps in a malunited Hoffa fracture case.
- Postoperative outcomes showed significant pain reduction and improved knee motion and stability.
- Custom implants may offer better solutions for complex malunions compared to traditional revision surgery.

## Abstract

Postoperative malunion following distal femoral Hoffa fractures is rare yet challenging. We present a novel approach using customized lateral unicompartmental knee arthroplasty (UKA) to address malunion with traumatic osteoarthritis, emphasizing functional restoration.

A 52-year-old male presented with persistent right knee pain (VAS score: 7/10), restricted range of motion (ROM: 0°–60° flexion), and gait instability two years after open reduction and internal fixation (ORIF) of a lateral Hoffa fracture. Imaging confirmed malunion of the fracture with traumatic osteoarthritis. A customized lateral femoral condyle prosthesis was designed using three-dimensional Computed Tomography (CT) reconstruction and implanted via a lateral parapatellar approach. Postoperative imaging (8–12 weeks) revealed optimal alignment and resolved fracture gaps. At 12 weeks, pain resolved (VAS: 1/10), ROM improved to 0°–125°, and Knee Society Score reached 85/100, with no complications.

Malunion after Hoffa fracture fixation is uncommon. Traditional revision ORIF may fail due to bone loss, while UKA preserves healthy compartments by restoring biomechanics. Customized implants address anatomical complexity, though long-term efficacy requires further study.

Customized UKA offers a viable solution for Hoffa fracture malunion with traumatic osteoarthritis, prioritizing joint preservation. This approach highlights the potential of patient-specific implants in complex orthopaedic salvage.

•The customised prosthesis was used for unicompartmental replacement of the lateral femoral condyle.•Lateral unicompartmental knee arthroplasty was performed for lateral condylar Hoffa fractures.•Unicompartmental arthroplasty of the lateral femoral condyle preserves the lateral cortical bone and maintains the attachment point of the lateral collateral ligament.

The customised prosthesis was used for unicompartmental replacement of the lateral femoral condyle.

Lateral unicompartmental knee arthroplasty was performed for lateral condylar Hoffa fractures.

Unicompartmental arthroplasty of the lateral femoral condyle preserves the lateral cortical bone and maintains the attachment point of the lateral collateral ligament.