Normal values of the shoulder strength in dependency on age and gender--comparison with the constant, UCLA, ASES scores and SF36 health survey
Authors: Thomas M, Dieball O, Busse M.
References: Z Orthop Ihre Grenzgeb. 2003 Mar-Apr;141(2):160-70.
AIM: The purpose of this study was to establish normal strength values of shoulder abduction in a male and female population aged between 6 to 90 years. These values were compared to the sex- and age-related values given by Constant for an Irish population, referred to as Constant 1991. Further strength values resulting from fixation of the measuring device at the deltoid insertion or at the wrist were compared. The assessment and comparison of shoulder function using different shoulder scores (Constant, UCLA, ASES) and the SF-36 was another aim of this study. Method: 120 male and 120 female probands were examined. For interpretation age- and sex-related groups of 20 probands each were used (group 1: 6 - 15 years; group 2: 16 - 30 years; group 3: 31 - 45 years; group 4: 46 - 60 years; group 5: 60 - 70 years, group 6: 71 - 90 years). Subjective and objective clinical parameters were registered, shoulder abduction strength was obtained using an isometric measuring device with fixation points at the deltoid insertion and at the wrist and the respective torque values were calculated. The shoulder function was quantified using Constant, UCLA and ASES scores. With the exception of group 1, the quality of life was measured with the SF-36 health-status questionnaire. RESULTS: Normal values of the shoulder abduction strength and valuation according to the Constant score are given for a German reference group related to age and gender. In addition to the Constant score more values for children are given. Strength values measured at the deltoid insertion (fixation point 1, FP1) and wrist (fixation point 2, FP2) are in a linear relation. Thus FP1 = 2.5 x FP2 and FP2 = 0.4 x FP1. If torque values instead of strength are used, 25 points correspond to 50 Nm. Total score values calculated by the use of the Constant score (methods published 1991) were markedly higher in groups 3 - 6 related to the values of Constant in the Irish population; the main reason is the higher abduction strength in our population. There exists a good relation between the Constant, UCLA and ASES scores (Constant 1991). The results of the SF-36 health survey were similar to the results of Bullinger et al. 1996. CONCLUSION: The normal values of C. R. Constant of an Irish population differ in part to those of our groups due to the different strength values. Our values may be more representative for German patients. The linear regression between strength values measured at a fixation point at the deltoid insertion or the wrist facilitates the calculation of each point from the other. This allows a comparison of the results of studies with different fixation points. The additional calculation of the torque allows a comparison of different studies independently of the fixation point of the strength measuring device.