# Three-Dimensional Morphometry Findings of the Proximal Humerus of the Indonesian Population

## TL;DR

This study measures the proximal humerus in an Indonesian population to inform better shoulder implant design.

## Contribution

Provides detailed 3D morphometric data specific to the Indonesian population for shoulder arthroplasty.

## Key findings

- Significant gender differences in HHH, ASD, and HHD measurements were observed.
- Body height correlated directly with HHH, ASD, and HHD measurements.
- Ethnic groups in Indonesia showed no significant differences in proximal humerus measurements.

## Abstract

Background

The design of implant components is the most critical prognostic factor in total shoulder arthroplasty as even minor discrepancies between the implant and the native anatomy can lead to failure. In this study, we aimed to describe the morphometry findings of the proximal humerus at our center, a national referral hospital located in the capital of Indonesia, serving a diverse population representing various Indonesian ethnicities.

Methodology

This observational, cross-sectional study included patients who had undergone upper extremity CT scans from January to December 2022. Demographic data such as age, sex, height, weight, body mass index, and ethnicity were collected from medical records. The measurements taken included the humeral head height (HHH), articular surface diameter (ASD), humeral head diameter (HHD), head-neck angle (inclination angle), and medial offset by CT scans.

Results

A total of 70 patients met the inclusion criteria. The average measurements were 14.3 ± 1.7 mm for HHH, 131.25° ± 5.15° for the head-neck angle (inclination angle), 40.50 ± 3.23 mm for the ASD, 44.86 ± 4.17 mm for the HHD, and 6.25 ± 1.93 mm for medial offset. HHH, ASD, and HHD showed significant differences between genders. Additionally, body height was significantly associated with HHH, ASD, and HHD. There was no significant measurement between ethnic groups in Indonesia.

Conclusions

A morphometric study of the proximal humerus revealed that the Indonesian population is vastly different than populations. Factors that need to be considered in selecting a shoulder implant include the patient’s height, gender, and race. There was a direct correlation between ASD, HHD, and HHH. Body height had a direct correlation with ASD, HHD, and HHH. The proximal humerus measurements in the Indonesian population were not significantly different between ethnic groups.