Tag Archives: glenoid

Addressing the Technical Challenges of Reverse Total Shoulder Arthroplasty and Lowering the Risk of Complications

Reverse total shoulder replacement arthroplasty, a technically challenging surgery, is often reserved for patients with serious shoulder pathology that cannot be adequately addressed with more conventional procedures. In patients who present with a massive irreparable rotator cuff tear and arthritis, a reverse total shoulder replacement can dramatically restore function and reduce pain. In the past, there would have been few good options for helping these patients. Nevertheless, according to Hyun-Min (Mike) Kim, M.D., Penn State Hershey Bone and Joint Institute, “Complications are seen in approximately 10 percent of patients who have this procedure done; about half of all complications involve instability. Mechanical impingement between the components and native tissue can contribute to instability and later to scapular notching.” To improve outcomes for these patients, Kim takes specific intra- and post-operative steps aimed at reducing risk of instability. Continue reading

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Filed under Musculoskeletal Sciences

Glenoid Loosening

Total shoulder replacement is a surgery typically conducted to alleviate symptoms of arthritis such as chronic pain, limited range-of-motion, and impaired daily functioning.

A common challenge in shoulder replacement is that the native glenoid bone is worn posteriorly. In such cases, the surgeon typically either implants a standard glenoid component malaligned relative to the scapula, or reams away healthy bone on the anterior side to achieve normal alignment, both of which can lead to complications. One of the most serious problems with shoulder replacement is loosening of the glenoid implant, which occurs in approximately 5 to 10 percent of cases. Such patients typically require revision surgery. Gregory Lewis, Ph.D., in collaboration with April Armstrong, M.D., shoulder surgeon, Penn State Hershey Bone and Joint Institute, is actively engaged in research to understand the internal micromechanics of replaced glenoids with the aim of decreasing the risk of glenoid loosening. New findings, presented at the 2012 Orthopaedics Research Society annual meeting, compare glenoid loosening and implant construct damage with a new type of posterior-augmented polyethylene implant to fill in the resulting gap from bone loss (versus a conventional implant). Lewis explains, “We used human cadaver specimens to test how well the two types of implants hold up under simulated, physiologic cyclic loading. At various cycle intervals, up to 100,000 cycles, [equivalent to twenty-five high-load shoulder movements per day for ten years], we measured external implant micromotions along with internal construct damage.

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Filed under Chronic Pain, Musculoskeletal Sciences

Clinical Pearl—Optimizing Glenosphere Position

April Armstrong, M.D.

April Armstrong, M.D.

The reverse-ball-and-socket implant has been approved for use in the United States since 2004 for patients older than 70 years of age with an irreparable rotator cuff tear accompanied by arthritis. For most patients, shoulder pain is reduced and function is improved, allowing improved forward elevation of the shoulder. It is, however, linked to a relatively high risk (about 15 to 30 percent) of post-surgical complications, including dislocation and loosening of the implants.

When introducing orthopaedic residents to performing this complex procedure, April Armstrong, M.D. shares her own clinical tips and pearls that she believes have benefited her patients and reduced the need for revision surgery.

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Filed under Clinical Pearl