A Prospective Cohort Study to Document the Clinical Outcomes in Shoulder Hemi-arthroplasty Using a PyC Spherical Interpositional Implant

Degenerative shoulder pathologies associated with a functional rotator cuff are currently treated by hemi-arthroplasty or total prosthesis replacement. The choice of surgery process is mainly made according to the status of the glenoid.

Concerning hemi-arthroplasty, two types of humeral prosthesis are usually used: anatomical stems or resurfacing head implants. Both provide good results. Nevertheless with these prostheses, patient can present with post-operative pains due to glenoid erosion, linked to the metallic compounds used in such a prostheses. To face this issue, it was decided to modify the metallic compounds, and in order to mimic the tribological properties of the cartilage, Pyrocarbon (PyC) was found to be the best material.

First application of PyC in a medical device was for cardiac valves in 1969. Currently more than 2 million people live with PyC cardiac valves. Mechanical and physical properties of PyC are in favor of its use in orthopedic surgery; furthermore, its biocompatibility plays an important role in its good acceptability.

As very good results were observed when used in hand and wrist, interposition PyC implant was suggested for shoulder. Another advantage was that such interposition device allowed performing less invasive surgery, a particularly important criteria for young patients.

INSPYRE shoulder prosthesis was then designed as a shoulder interposition implant intended for partial replacement of the gleno-humeral joint. This implant is inserted between the glenoid cartilage and the humeral metaphyseal cavity. It is indicated in primary surgery to relieve severe pain or significant disability caused by degenerative pathologies, e.g., osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, primary and secondary necrosis of the humeral head. The rotator cuff must be functional.