New Total Shoulder Implant Improves Joint Access

A new stemless total shoulder system uses an aspherical head design that provides increased exposure to the glenoid and minimal bone removal.

The Arthrosurface (Franklin, MA, USA) OVOMotion Shoulder Arthroplasty System is a stemless total shoulder system with an inlay socket design intended for patients with painful and/or severely disabled shoulder joints as a result of arthritis, traumatic events, or avascular necrosis (AVN). The system is comprised of a chrome-cobalt ovoid-shaped articular component with seven offset choices and a titanium plasma spray undercoating, and a cannulated titanium fixation component that connects to the ovoid head with a Morse taper.

The surgical technique involves off-axis preparation of the glenoid fossa using a three-dimensional (3D) mapping system. Following a series of reaming and trialing, best fit is determined. Once the socket is reamed to the correct depth, tunnels are drilled for the peg holes and perforations are made in the bone bed. Bone cement is then placed and pressurized using a silicon finger sleeve and the shoulder implant is seated and impacted into place. The construct provides biomechanical stability, immobile fixation, and a stress bearing contact where it’s most needed, at the bone/prosthetic interface.

“The OVOMotion Shoulder Arthroplasty System builds upon the outstanding clinical results of the OVO System and greatly facilitates surgical access, speed and reproducibility,” said Steve Ek, CEO of Arthrosurface. “It also sets the stage for our future three-element modular stemless system that will ultimately allow surgeons to intra-operatively choose between stemless, traditional, and reverse options.”

“With the new system, the additional 12.5mm of bone removed from the humeral head has truly improved the technical portion of the procedure. This allows for easier visual and manual access of the glenoid,” said Michael Gombosh, MD, of South Florida International Orthopaedics (Miami, USA). “With improved visualization, you are able to obtain a more accurate assessment of the morphology and wear pattern within the glenoid, but also establish improved access for glenoid preparation and release of the posterior capsule.”

The glenoid fossa is a shallow, pyriform articular cartilaginous surface, with its margins attached to the fibrocartilaginous glenoid labrum, thus deepening the cavity. Together with the humerus, it forms the glenohumeral joint, which is reinforced by the rotator cuff. Due to its shallow angle, the glenoid cavity allows the shoulder joint to have the greatest mobility of all joints in the body, with 120 degrees of unassisted flexion. To maintain its stability, strong glenohumeral ligaments and muscles help hold the humerus in place.

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