# Excision of Intra-articular Knee Heterotopic Ossification Using a 70° Arthroscope

## TL;DR

A rare case of bone growth in the knee joint was successfully removed using a specialized arthroscope, allowing the patient to recover fully.

## Contribution

Demonstrates successful excision of intra-articular knee heterotopic ossification using a 70° arthroscope.

## Key findings

- A 24-year-old female with intra-articular knee HO showed improvement after excision using a 70° arthroscope.
- Direct visualization with the 70° arthroscope enabled safe removal of the bone growth.
- The patient remained asymptomatic and returned to sports after three months.

## Abstract

Heterotopic ossification is ectopic lamellar bone formation within soft tissue and can result in significant functional limitations. There are multiple underlying etiologies of HO including musculoskeletal trauma and traumatic brain injury. Intra-articular HO of the knee is rare and is typically located within the cruciate ligaments. We report a case of a 24-year-old female who presented with worsening right knee pain and limited knee extension two and a half years after a motor vehicle crash with multiple lower extremity fractures. Physical examination of the knee revealed anterior pain, limited extension, and a palpable infrapatellar prominence. Imaging showed a retropatellar tendon, intra-articular excrescence of bone proximal to the anterior tibial plateau. Diagnostic arthroscopy with a 70° arthroscope identified HO at the proximal anterior tibial plateau, which was excised with a high-speed burr under direct visualization. At the three-month follow-up, the patient remained asymptomatic and returned to sport. Retropatellar tendon, intra-articular anterior knee HO is a rare but debilitating clinical entity that can be successfully and safely managed with excision under direct visualization using a 70° arthroscope.