Classifying radiographic changes of the pubic symphysis in male athletes: Development and reproducibility of a new scoring protocol

Purpose

To develop a specified radiographic scoring system for the pubic symphysis and adjacent bones, and to examine the intra- and inter-rater reproducibility of this system.

Method

Development of the scoring protocol was performed in three stages using AP pelvis radiographs of 102 male adult athletes. The final protocol included 5 overall scoring items, which included further specification of locations: 1) bone lucency (erosion-like configuration and cysts), 2) proliferation, 3) fragmentation, 4) sclerosis, and 5) joint space width. Intra- and inter-rater reproducibility were determined using Cohen’s kappa statistic (κ) and intraclass correlation coefficient (ICC). The standard error of measurement (SEM) and minimal detectable difference (MDD) were also determined.

Results

We present a radiographic scoring protocol with clear definitions and examples to improve clinical usability. Intra-rater reproducibility was: bone lucency (erosion-like configuration or cysts): κ = 0.67 (95 %CI 0.56−0.78), proliferation: κ = 0.54 (95 %CI 0.38−0.70), fragmentation: κ = 0.80 (95 %CI 0.67−0.93), sclerosis: κ = 0.60 (95 %CI 0.49−0.71), and joint space width: ICC(2.1) 0.85 (95 %CI 0.78−0.89), SEM 0.4 mm, MDD 1.2 mm. Inter-rater reproducibility was: bone lucency: κ = 0.61 (95 %CI 0.50−0.72), proliferation: κ = 0.34 (95 %CI 0.20−0.48), fragmentation: κ = 0.67 (95 %CI 0.50−0.84), sclerosis: κ = 0.30 (95 %CI 0.17−0.43), and joint space width: ICC(2.1) 0.72 (95 %CI 0.59−0.81), SEM 0.5 mm., MDD 1.5 mm.

Conclusions

The Aspetar pubic symphysis radiographic scoring protocol contains five overall scoring items, with additional specifications. These five items showed moderate to almost perfect intra-rater reproducibility, and fair to substantial inter-rater reproducibility. This protocol provides the basis for use in clinical practice, and will allow future investigations of the clinical significance of radiographic changes at the pubic symphysis in athletes.

Other Information

Published in: European Journal of Radiology
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.ejrad.2020.109452