A STUDY OF MORPHOMETRIC ANALYSIS AND MEASUREMENT OF ANGLE OF TORSION OF THE HEAD OF HUMERUS AND SHOULDER ARTHROPLASTY

Abstract

Back ground: Humerus is the longest of the long bones of superior extremity.It”s head articulates with scapular glenoid cavity to form the gleno-humeral/Shoulder joint.The rounded head of Humerus is too weakly supported in the scapular glenoid cavity lined by glenoid labrum which makes it the most mobile and most unstable nd joint and so most commonly dislocated joint of the human body.Also the humeral head part is the 2 most important part of shoulder arthroplasty. Aim of the study is to make a clinical evaluation of parameters used in prosthesis design for the humeral component applied in arthroplasty of the proximal upper extremity. Methods: A total of 100 (Rt -58,Lt –42 ) dry human Humerus available in the Department of Anatomy of Calcutta National Medical College,Kolkata,West Bengal and Nilratan Sircar Medical College,Kolkata,West Bengal were taken for the study.The Humeral heads are measured in supero-inferior(SI) diameter, and antero-posterior diameter(AP), The width of Humeral head (Wdth),and angle of Humeral Torsion were measured. At the very beginning the both sided Humerus taken for the study are properly numbered using permanent marker pen.The width of the Humeral head(Wdth) is measured 1stly by pressing the head in modelling dough and when the mould is prepared,semisolid plaster of paris is lled into the mould. After drying the replica of humeral head is smoothened upto the mark of anatomical neck of humerus thus proper width can be measured. The superoinferior(SI) diameter, and antero-posterior diameter(AP) were measured by digital slide callipers by placing it directly onto the surface of consequently numbered humeral heads. The width of Humeral head (Wdth ) were measured from these replica(properly numbered) humeral heads, made of plaster of paris at the middle, the highest thickness was measured. The measurements are taken via spreading slide calipers in milimeters. For measuring the angle of humeral angle of torsion ,we xedly placed the humerus on to a area over the smooth part of the vertical wall which was meeting another horizontal wall at 90 degrees angle thus the line joining the two epicondyles of humerus lies parallel to the vertical wall.Now placing the straight edge of the protractor onto the upper end of humerus the angle of humeral torsion is measured. Results: Both sided Humerae were analysed separately for Morphological measurement, and angle of Humeral torsion.Mean values for SI were 41.31+3.46mm (Right side) and 40.91+3.27mm(Left side). Mean values for AP were 38.27+3.05mm (Right side) and 37.91+2.70mm(Left side). Conclusion: This study will contribute some relevant data and help the orthopaeditians in dealing with cases of shoulder pathology and shoulder arthroplasty cases.