# Total joint replacement with the stock Biomet system in adult hemifacial microsomia without glenoid fossa: a case report and literature review

## TL;DR

A case report shows successful use of a stock Biomet system for joint replacement in a patient with facial microsomia and bone deficiency.

## Contribution

Demonstrates a novel approach using autogenous bone grafting to enable stock TJR in complex facial microsomia cases.

## Key findings

- Autogenous bone grafting improved the frontal ramal angle by 6.5 degrees.
- A 12.42 mm pogonion advancement was achieved through staged surgical procedures.
- Stable functional and aesthetic outcomes were maintained for seven years with the stock Biomet TJR.

## Abstract

In patients with hemifacial microsomia accompanied by mandibular fossa deficiency and severe atrophy of the mandibular ramus, customized total joint replacement (TJR) is commonly used to restore masticatory and joint function and improve facial asymmetry. However, in countries where customized TJR is not approved, or for patients for whom the cost is prohibitive, a stock TJR system must be considered. In cases with a severely medially inclined frontal ramal angle and a lack of supporting bone for the fossa component, using a stock TJR poses significant technical challenges.

This case report describes the use of autogenous bone grafting to overcome these limitations. An 18-year-old male with HFM type IIB on the left side received staged procedures, including bone grafting between mandibular proximal and distal segments to increase the frontal ramal angle, autogenous reconstruction of the mandibular fossa to enable fixation of the TJR fossa component, and orthognathic surgery.

The frontal ramal angle improved by approximately 6.5 degrees, and 12.42 mm advancement of the pogonion could be achieved in lateral cephalogram. Successful functional and esthetic outcomes were achieved, with stable maintenance of a stock Biomet TJR over a seven-year period.