Proximal Humerus Fracture Open Reduction Internal Fixation
The development of locking plate technology has established a gold-standard for proximal humerus fracture fixation in the non-geriatric adult population. The locking plate allows screws, often with threads on the circumference of the head, to engage into the plate and create a rigid fixed angle construct. The surgical incision is either through the front or side of the shoulder. The implant is an anatomically contoured metal plate and the screws aimed at both compressing across the fracture as well as stabilizing the bone to prevent collapse of the humeral neck.
Proximal Humerus Fracture Operative Fixation
Operative fixation of proximal humerus fracture in the non-geriatric, adult patient aims to preserve the natural shoulder articulation, making arthroplasty option less than ideal. The bone fragments must be appropriately realigned either through manipulation or by surgically opening and dissecting down to the fracture site.
Treatment options include closed reduction percutaneous pinning with threaded pins. This technique does not afford the most stable fixation, and pins can migrate either deep and damage cartilage or migrate out of the fracture side resulting in loss of reduction. Some low fracture patterns through the surgical neck of the humerus can be fixed with an intramedullary rod inserted from the top of the humerus and then locked on either end of the fracture site with screws. This procedure violates the rotator cuff and can leave lasting shoulder pain. The advent of locking plate technology heralded in proximal humerus locking plates that aim to preserve the native anatomy and articular surface of the shoulder joint.
After the surgery is complete, patient will often be required to wear a sling and attend physical therapy to regain function at an appropriate pace.
Proximal Humerus Fractures
Proximal humerus fractures in the non-geriatric, adult population occur secondary to high energy trauma. Fractures of the humeral head that result in three or four parts, when the head splints down the middle or when the humeral head is fractured and no longer sits in the humeral-glenoid shoulder joint require operative treatment. Without surgery the affected shoulder will develop post-traumatic osteoarthritis, and significantly decreased functionality with an increase in pain.
AxSOS 3® Ti Proximal Humerus Plating System is a monoaxial anatomically contoured plate that provides hybrid fixation to allow fracture stabilization with a lag screws as well as locking options. There are seven options for screw placement into the humeral head and eight metaphyseal K-wire and suture holes. The plate is available in length up to 306mm.
Reverse Shoulder Arthroplasty
The development of locking plate technology established a gold-standard for proximal humerus fracture fixation, however the treatment was still limited to an acceptable fracture reduction and relying on that bone to heal, making it not ideal in older patients. Another option is replacing the humeral head with a spherical metal implant and allowing the implant to articulate with the native concave glenoid fossa. In patients that also have ineffective rotator cuffs- either from longstanding tendinopathy or from an irreparable tuberosities- the solution is to revere the natural concave-convex relationship in the shoulder. A metal hemisphere is implanted on the scapular side while a concave implant is used on the humerus side, the deltoid muscle now has a longer fulcrum and greater mechanical advantage, eliminating the necessity for the rotator cuff muscles.
Stryker ReUnion® RSA Reverse Shoulder Arthoplasty system is designed for primary fractures or revision surgery. It has a fully convertible platform for the humeral stem, meaning components for their shoulder hemiarthroplasty, shoulder anatomic total arthroplasty and reverse shoulder arthroplasty can all interchangeably fit, making a conversion to a reverse total shoulder arthroplasty relatively easy if the rotator cuff fails on a primary hemiarthroplasty or total arthroplasty. The glenoid-sided component contains variable angle locking screws of up to 30 degrees as well a 3D printed porous metal backing to encourage bony ingrowth.