The New ‘Coimbra Method’: A Biologically Appropriate Method for Recording Specific Features of Fibrocartilaginous Entheseal Changes

Abstract

A working group was established in 2009 during a workshop in Coimbra, Portugal to review the various methodologies used to record entheseal changes (EC), and develop a standardized system to facilitate comparisons across studies. This paper presents the first results of the “Coimbra method”; a new qualitative method for recording fibrocartilaginous entheses based on the types of changes observed. Materials and Methods: The new method divides the enthesis into a margin (only the area opposite the acute angle of fibre attachment) and surface (which also includes the remaining margin). Five features are recorded: bone formation, erosion, fine porosity, macroporosity, and cavitation. A total of 67 male skeletons from the identified SIMON collection, Geneva, Switzerland all of whom were manual workers and aged between 20 and 79 years, were used for this study. Six skeletons were used by the authors as exemplars to determine standard criteria for recording each change. Thirty male skeletons were selected to test intra- and inter-observer error of the new method. An additional 31 skeletons were used for a preliminary test of the relationship between EC and age, using exploratory statistics and ordinal regression. Results: Intra- and inter-observer error had a similar percentage agreement of around 70%. The exploratory statistics indicated a general trend for increased scores of each feature with age, but ordinal regression demonstrated that this was not statistically significant (p<0.05) for all features. Discussion: The recording method is repeatable for some entheses. The effect of the ageing process is dependent on enthesis and EC feature. Unlike most methods, the “Coimbra method” records EC features in detail; this has the advantage of allowing studies of the relationship between different EC and age, as well as sex and occupation. Further studies on larger identified skeletal collections are needed to test the effect of age, sex and occupation.