Test parameters for anatomical shoulder replacement systems are based on a wear study conducted using a modified hip joint simulator.
The “PI-62 Anatomical shoulder system wear test” standard, developed by PI Medical Implants, describes the requirements for the wear test of the anatomical shoulder system.
While testing, the following movements are applied to the implant system simultaneously:
In general, in anatomical terms, abduction is classified as the movement of a limb or appendage away from the midline of the body. In the case of arm abduction, it is the movement of the arms away from the body in the plane of the trunk (coronal plane). Adduction is the movement of a joint or body part inward toward the midline. Abduction involves the movement of a body part away from the midline.
Flexion is a movement that causes the angle between the bones of a joint to decrease, such as when a person bends their elbow joint. Flexion movements occur in the sagittal plane (the horizontal line that runs from right to left through the body) around the frontal axis. Extension is the increase in the angle between the two parts of a joint, or stretching. As a result of the movement, the two parts of the body in question move away from the point of contact or directly away from each other, within the limits allowed by the joint.
A constant load of 756 N (plus/minus 50 N) is applied during testing. The translation resulting in rim loading during abduction/adduction is directed at a 45 degree angle from the long axis of the glenoid component. The amount of translation required to create rim loading during abduction/adduction depends on the radial incompatibility between the glenoid component and the humeral component and is adjusted individually.
Wear test is performed for 5 million cycles. Wear is detected gravimetically.
Shoulder replacement removes damaged areas of bone and replaces them with parts (implants) made of metal and plastic. This surgery is called shoulder arthroplasty. The shoulder is a ball-and-socket joint. The rounded head of the upper arm bone (the ball) fits into a shallow socket in the shoulder. Joint damage can cause pain, weakness, and stiffness. Shoulder implants come in several different shapes and sizes. Replacement options include partial and full replacements using anatomic or reverse implants.
Depending on the type of joint damage, a reverse total shoulder replacement, a partial shoulder replacement, or an anatomic total shoulder replacement may be performed. In an anatomic total shoulder replacement, the ball and socket are replaced with implants that mimic the natural shape of the bones.
In an anatomic total shoulder arthroplasty procedure, the humeral head is removed and replaced with a metal replica of the humeral head. The glenoid is then resurfaced with a plastic plate with pins on the back, which are cemented into holes placed in the glenoid (socket) using bone cement.
Glenoid component failures still represent the most common complication in total shoulder arthroplasty. These failures are due to several factors, including ultra-high molecular weight polyethylene (UHMWPE) wear. One cause of UHMWPE wear in total shoulder arthroplasty may be the use of a spherical prosthetic humeral head versus a radially mismatched UHMWPE glenoid component, resulting in decreased glenohumeral translations, glenoid edge loading, and high translational forces during shoulder motion.
The anatomical shoulder system wear test is largely to evaluate the in vitro wear of an anatomical total shoulder prosthesis with non-spherical mismatched bearings with conventional materials reversed.
Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “PI-62 Anatomical shoulder system wear test” standard with its trained and expert staff and advanced technological equipment.
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