# Assessing Adequacy of Marker Ball Placement in Preoperative Pelvic X-rays: Are We Missing the Mark?

## TL;DR

This study shows that simple educational interventions can significantly improve marker ball placement in hip fracture radiographs, enhancing preoperative planning accuracy and patient safety.

## Contribution

The study demonstrates that low-cost educational measures can effectively improve marker ball placement compliance in pelvic radiographs for hip fracture patients.

## Key findings

- Initial compliance with marker ball placement was only 59%, but improved to 80% after educational interventions.
- Educational interventions significantly increased the visibility and correct positioning of marker balls in radiographs.
- Sustained improvements require ongoing audit and education in routine radiography practice.

## Abstract

Introduction

Accurate preoperative templating in hip arthroplasty depends on correct marker ball placement during anteroposterior (AP) pelvic radiographs. Misplacement can compromise prediction of femoral offset and leg length, increasing operative complexity and complication risk. This closed-loop audit evaluated marker ball adequacy in patients with intracapsular neck of femur fractures and assessed the impact of targeted interventions.

Methods

A retrospective audit was conducted at Poole General Hospital, United Kingdom. Patients with radiologically confirmed intracapsular fractures between January and May 2025 were included; exclusions were extracapsular fractures, age <18, open fractures, and prior contralateral hip replacement. Audit standards required marker balls to be entirely visible and positioned between femurs, inferior to the symphysis pubis, with an agreed compliance target of 80%. Interventions included educational presentations, poster reminders, and a mandatory checklist. A re-audit was performed from June 1-30, 2025. Statistical analysis was performed using chi-square testing.

Results

Cycle one included 60 cases, with marker balls present in 45% (n=27). Of these, 59% (n=16) were entirely visible and 41% (n=11) were correctly positioned, yielding overall compliance of 59%. Following interventions, cycle two (n=50) demonstrated significant improvement: marker balls present in 78% (n=39), with 84% (n=33) entirely visible (p=0.042) and 82% (n=32) correctly positioned (p=0.0014). Overall compliance increased to 80%, meeting the target standard.

Conclusion

Simple, low-cost educational measures significantly improved marker ball placement in pelvic radiographs for hip fracture patients. Embedding such interventions into routine radiography practice enhances the accuracy of preoperative templating, promotes patient safety, and reduces medico-legal risk. Ongoing audit and education are essential to sustain improvements.