A Study on the Accuracy of the Computerized Radiographic Measurement of the Femoral Head Size

A Study on the Accuracy of the Computerized Radiographic
Measurement of the Femoral Head Size

Pandey Madhu, MD ¹, Russell Salic, MD ², Bernard Antolin MD, FPOA ³

1. Researcher, N M M C, Department of Orthopedics.
2. Coresearcher, N M M C, Department of Orthopedics.
3. Adviser, N M M C, Department of Orthopedics.

*Correspondence to: Bernard Antolin.

Copyright
© 2026 Bernard Antolin is an open access article distributed under the Creative Commons Attribution   License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 29 May 2026

Published: 15 June 2026

DOI: https://doi.org/10.5281/zenodo.20730917

Introduction

With the advent of new technology Digital X-ray systems are now widely used in hospitals nationally and internationally. Most systems have facilities to take measurements from the images. Which can be used in accurate pre-operative planning. Insertion of undersized head is a cause of increased joint loading of the acetabulum and may result in acetabular erosion. Inappropriate implant size could affect the outcome of the surgery with reported complications such as stress shielding, loosening ,micro motion, dislocation ,acetabular erosion .Despite the use of larger head sizes dislocation continues to be the most common mode of failure leading to revision .Due to the importance of arthroplasty for the success of hip joint replacement, this study is aimed to analyze the difference in conventional radiographic method, digital radiograph and actual measurement of the femoral head. Conventional method of measurement is from the X- ray film measuring the widest diameter of the femoral head subtracting 10% and preparing implant sizes +_5 .

This study could be used as a tool for the radiographic and actual femoral head size assessment by decision making clinical practice pre-operatively This study may reliably predict the size of the implant required for hemiarthroplasty to treat hip fractures.

GENERAL OBJECTIVE

To evaluate the accuracy of the computerized radiographic size of the femoral head who underwent partial hip arthroplasty.

SPECIFIC OBJECTIVES:

To measure the femoral head size using computerized radiographic system.

To measure the actual femoral head size intra-operatively.

To determine the difference between the CR measured femoral head size and the actual size of the dissected head between pre op femoral head size and the actual size of the diseased head.

Due to the importance of arthroplasty for the success of hip joint replacement, this study is aimed to analyze the difference in conventional radiographic method, digital radiograph and actual measurement of the femoral head.

This study will be useful in assessing difference in radiographic and actual size assisting in decision making during clinical practice.

Study Design

Descriptive Analysis

Materials and Methods

Pre operative pelvic Xray AP and cross table lateral views were taken upon admission. All patients admitted at NMMC for hemiarthroplasty from January 2013 were included in the study. Computerized Radiographic measurements were taken preoperatively.

Intraoperative

The diameters of femoral heads in 24 Hip joints were measured using a caliper at the head equator. Intra-operative measurements were noted and recorded as shown in the figures below.

Fig 1.Measurement shown in the right femoral head   Fig1.1 Measurement using Traumacad Fig 2.1-2.3 showing intraop measurements using head sizer and fig 2.6vernier caliper

Results

In this study there were 17Females and 7 males with a mean age of 70 years old who underwent Partial hip Arthroplasty from January 2013 to November 2014. Eight patients had intertrochanteric fractures while other17 patients sustained femoral neck fractures.

Table 1.0 Measurement of femoral head by different modalities

Preoperatively using the computerized method of measurement of the femoral head of each patient was measured. Double set up Radiographic size -10 % ; plus or minus 51 mm, different sizes ranging from the values taken were prepared. Five patients had the same radiographic size with the actual femoral head size. Eleven patients had a difference value of 1mm with the radiographic size.

[Chart Placeholder: Comparison Bar Graph of Radiographic vs Caliper Measurements]

The table above presents the mean radiographic measurement (46.0833mm) with Standard deviation 3.374 and the mean actual measurement (45.2916mm) with Standard deviation 3.182 of the patients (n=24). It can be seen that there is only a mean difference of 0.7 mm between the measurements taken by the two modalities. Statistically this study showed that 80% of the patient's radiographic size is 1mm higher with what of the actual femoral head size.

Statistical Breakdown Table