May the subacromial space decrease in patients with thoracic hyperkiphosis?

May the Subacromial Space Decrease in Patients with Thoracic Iperkyphosis? Introduction: lt is known that stretched and weakened scapular and midthoracic kypho- sis are common companions of subacromial primary extrinsic syndrome. In fact it has been suggested that the pathological spatial orientation of the scapula, owing to thoracic kyphosis, may decrease the subacromial space (SS). This statement arises from sporadic observations. In fact no studies have measured the SS on x ray films in significant groups of patients with and without thoracic kyphosis. We have measured this space in a large number of patients with iperkyphosis and volunteers both shoulder painless and without radiographic signs of shoulder instability, os acromiaie, calcific tendinitis, AC or acromial Material and methods: The 72 patients with idiopathical (11) or acquired (61) iperkypho- sis >40° (according to the Cobb's method) examined, during 1999 were requested to un- dergo radiographic evaluation of the right shoulder. 8 did not accept, Of the remaining 64 patients, 11 were excluded from the study because during their life they had sustained pain in one of both for a term of, at least, 3 days. All the others were x-rayed, using a true AP view (standing) with the arm in internal rotation and with a 20°caudal tilt and an ax- illary view. The SS was measured, in the AP vievvg from the dense cortical bone marking the inferior aspect of the acromion at a point directly above the humeral head and recorded as the smallest distance between this point and the articular cortex of the humeral head (magnification 11%). Another 4 e 8 patients were excluded, respectively, because the superimposition of the scapular spine did not permit a good visualization of the SS or because x rays showed: os acromiale (1) AC or acromial spurs (4), calcific ten- dinitis (2), signs of GH instability (1). The remaining 41 patients (8M, mean age 59 yrs; 33F mean age 66 yrs) and 60 volunteers (23 M, mean age 61 yrs; 37 F mean age 60 yrs) represent, respectively the studied group and the controls. With the numbers available, no significant difference could be detected. Results. The SS was 7.45 2.16 mm (AV 1- SD) and 9.02 e 1.62 mm, respectively in female with iperkyphosis and volunteers; while in male groups the values of the measurements were, respectively, 7.01 and 8.65 mm. To evaluate whether a decrease of the SS with increasing age was registered, we divided the more representative group (females) into two groups constituted by people younger and older than 60 yrs of age. ln the first subgroup the space was 8.57 e 1.13 mm (iperkypho- sis) and 9.10; 1.48 mm (volunteers), respectively, while in the second it was 6.84 x 1.48 and 8.94 e 1.81 (p> 0.05). Similar results emerged also in male subgroups. Conclusion. The acquired thoracic iperkyphosis is more frequent in females older than 60 years of age. For this reason they represent the more numerous sample of our study. 12.5% of all studied subjects had a SS of less than 7 mm (-11%). Therefore this value is not the limit between normal and pathological conditions. Thoracic iperkyphosis must be consid- ered a risk factor for subacromial impingement syndrome, in fact, in both sexes, a lower value of the space was observed in the groups constituted by patients with the thoracic iperkyphosis with respect to those formed by volunteers. It has been suggested that, in people without iperkyphosis, the SS was significantly greater in men and that only in males it undergoes a slight decrease with age. Our study shows that the SS in female volunteers is similar to that of the males and decreases with increasing of age.