Abstract
Introduction: The Constant Score Functional Assessment (CS) is now the standard method of assessing shoulder disability in Europe. It has been observed that the CS values decrease with age and attempts have been made in Canada (Constant, 1986), Germany (Tempelhof, 1999), Switzerland (Gerber, 1992) and US (Romeo, 2002) to produce national norms against which the subject’s Constant Score might be compared. Unfortunately the methods used for measuring the “Strength” category of the CS have varied and thus the results are not uniformly comparable. This study has used three methods of evaluating “Strength” for the CS in a randomised group of subjects aged over 50 in order to establish the UK norms.
Methods: 200 patients stratified for age over 50 were invited to take part in this study for which Local Ethics Committee approval had been obtained. Of these 200, 46 patients (21 males) attended and all attenders had a CS carried out with the “Strength” measurement made in 3 ways – 1) maximum force using a fixed spring balance – FSB(max); 2) maximum force using a commercial myometer – M(max); 3) mean force from 2 to 4 seconds using a commercial Myometer – M(mean). The CS values have been plotted for age and sex.
Results: The results for the 25 females and 21 males using M(mean) are shown below. The middle line represents the linear regression with the 95% Confidence Intervals above and below.
Discussion: The results confirm that there is a deterioration in the CS with age in both men and women. The outliers in three of the four graphs will be discussed and the analysis represented after removal of outliers for which there is a justification for exclusion. The differences between the left and right shoulders will be discussed.
Significant differences were identified between the 3 methods of “Strength” measurement, highlighing the need for a uniform method of carrying out the CS.
Conclusion: The UK pattern of deteriorating CS with age mirrors that seen in other countries but the values are different. These differences are significant and make it necessary to reconsider the use of the corrected CS. It is probably wiser to use the uncorrected CS but refer to normal values as a guide for the expected CS at different ages.
Correspondence should be addressed to Carlos Widgerowitz, Honorary Secretary BORS, Division of Surgery and Oncology, Section of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Tort Centre, Dundee DD1 9SY, Scotland.
