Total shoulder replacement: How to perform

Last updated on July 6 2022

Description

Total shoulder replacement (TSR), also known as total shoulder arthroplasty, is a surgery for restoring comfort and function of the shoulder. This involves replacing the shoulder joint with artificial parts. 

The top of the upper limb bone, called the humeral head, is dislocated from the socket of the scapula, or glenoid. The humerus is prepared for the prosthetic humeral stem. The size of the prosthesis head can be determined by superimposing the trial head over the resected humeral head. If no head fits perfectly, choose the smaller option.

This procedure allows knowing the measurements needed to perform the surgery.  The average angle of inclination is approximately 135° for the humerus. The anatomical neck defines these individual angles. The center of rotation should be where the neck shaft angle is 135°. If the neck shaft angle is < 135°, it is a varus humeral neck-shaft, and if the neck shaft angle is > 135° it is a valgus humeral neck-shaft.

Measurements

The measurements made by the procedure are displayed in the image:

• Humeral Head Diameter (HHD): length of the line that starts on the lower point of the humeral neck and ends on its upper point;
• Neck Shaft Angle (NSA): angle that a perpendicular line to the Resection Line does with the humeral axis;
• Humeral Intramedullary (IMC) canal diameter: length between the lateral and the medial side of the intramedullary canal;
• Humeral Head Offset (HHO): length between the coracoid process and the most lateral point of the greater tuberosity.

Auxiliary references 

To show this procedure, PeekMed® needs additional references:

• Humeral Axis: a line crossing the center of the humeral shaft;
• Vertical line: a line perpendicular to the Neck length line.