抄録
The untreated and over-two-year results of 296 cases (516 joints) of MDI were studied. The influences of age, sex and sporting activity on the onset and the spontaneous recovery were investigated. The incidence of female patients was 1.5 times higher than that of male patients in the 13-34 age bracket. The mean age of the onset in the sporting groups was statistically lower than in the non-sports group (15.4years old in the over-head sports group,16 years old in the other sports group and 21.8 years old in the non-sports group). The correlation between the age of onset and the age when starting a sports was recognized in all the sports the female patients played but it was recognized in only the over-head sports group in male patients. Spontaneous recovery was recognized in 41 joints. In those cases the mean age of the onset was 14.5 years old, and 19 years old in the non-recocery group. The younger the age of the onset is, the higher the incidence of spontaneous recovery is. The incidence of spontaneous recovery in male patients was higher than in female patients. The incidence of spontaneous recovery in the group who discontinued over-head sports was 14.6% and 4.9% in the group who continued it. It was about 14% regardless of continuation or discontinuation of any other sports, but no spontaneous recovery was recognized in the group which changed sports from non-overhead to overhead. There was no spontaneous recovery in cases of type III of Endo's classification and general joint laxity. We conclude as follows. (1) Sex hormones have a great influence on the onset and the spontaneous recovery of MDI. (2)All sports female patients play and the over-head sports male patients play induce the onset of MDI. (3)Over-head sports interfere with the spontaneous recovery of MDI.
