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Polyethylene wear linked with osteolysis after shoulder arthroplasty
Results of this study indicate polyethylene wear following should arthroplasty may be associated with the development of osteolysis of the proximal part of the humerus and that glenoid issues have a large effect on humeral bone.
Researchers studied 395 shoulders with primary osteoarthritis that underwent shoulder replacement. Radiographs were evaluated for osteolysis and stress-shielding of the proximal part of the humerus and loosening of the humeral and glenoid components. Arthroplasty configurations included hemiarthroplasty with cement in 30 shoulders, hemiarthroplasty without cement in 36 shoulders, total shoulder replacement (TSR) with a cemented stem and a cemented flat-backed glenoid component in 89 shoulders, TSR with a cemented stem and a cemented convex-backed glenoid component in 94 shoulders, TSR with a cemented stem and an uncemented metal-back glenoid component in 79 shoulders and TSR with an uncemented stem and a cemented convex-backed glenoid component in 67 shoulders.
During a mean follow-up of 8.2 years, researchers found a significantly greater constant score and shoulder motion at the latest follow-up examination compared with preoperative measures. After periprosthetic fracture, one cemented stem loosened while another was at risk for loosening. Researchers found stress-shielding in 63% of the shoulders with uncemented stems, while osteolysis of the proximal part of the humerus occurred in 43% of shoulders that underwent TSR. According to study results, patients with osteolysis had a poorer clinical outcomes and shoulders with osteolysis around the proximal part of the humerus had more glenoid loosening and polyethylene wear.
“The findings of this study demonstrate that the glenoid component has a significant effect on humeral bone in shoulder arthroplasty. Polyethylene wear from the glenoid implant appears to be associated with the development of osteolysis of the proximal part of the humerus after total shoulder arthroplasty,” the researchers wrote. “With the implant design used in this study, stress-shielding was only observed with uncemented stems. The uncemented and cemented stem designs analyzed in the present study appear to be comparable and can both be recommended for clinical use.”
Disclosures: Walch received royalties from Tornier. Deutsch is a consultant for Arthrex, Mitek, Wyeth and Wright Medical. Edwards is a consultant for and received consulting and other fees from Tornier, as well as patents and royalties from Orthohelix and Tornier. Loew is a consultant for Tornier. Boileau is a consultant for Smith & Nephew, has a patent with Tornier and Smith & Nephew, received royalties from Tornier and travel accommodations from DePuy Mitek.