Paragon Stem Study: Is there a correlation between the size of the femoral head and the size of the femoral prosthesis?

Presenter’s name (Last, First): Jeong, Dooho

Qualifications: MBBS, MD

Affiliations: Nepean Hospital/John Hunter Hospital

Other authors:
(Prasad Athreya/MBBS, FRACS (Ortho)/NepeanHospital), (Rami Sorial/MBBS, FRACS, FAOrthoA/Nepean Hospital), (Simon Coffey/MBBS, FRACS,FAOrthoA/Nepean Hospital)


Background / Introduction:
Pre-operative templating is an essential part of total hip arthroplasty that helps surgeons to anticipate the implant size and to identify potential difficulties that may arise. Traditional preoperative templating is challenging in some circumstances such as in neck of femur fractures where anatomy is distorted, or where adequate radiographs cannot be obtained.

Patients / Methods:

This study looked at the correlation between the native femoral head diameter and femoral stem implant size. Femoral head sizes and femoral stem implant sizes were collected from one hundred primary total hiparthroplasty cases and forty hemiarthroplasty cases for neck of femur fractures.


There was a positive correlation between femoral head size and femoral stem implant size. In the hemiarthroplasty cohort, a correlation coefficient of 0.60 was found, and in the total hip arthroplasty cohort, a correlation coefficient of 0.51 was found. Hence a moderate linear correlation was demonstrated in both cohorts.


While this result indicates that for a larger femoral head size a larger femoral stem implant size is likely to be inserted, it is still difficult to predict the exact femoral stem implant size due to the high variability in the stem size.

Level of Evidence & Study type: Level III

Declarations of Conflict: No conflicts of interest