Raiss and colleagues described the radiographic changes that develop around one tapered humeral stem across six shoulder arthroplasty configurations, and how those changes relate to clinical outcome.
Retrospective series from 5 shoulder centers, 1991 to 2007: 395 shoulders with primary osteoarthritis, all with the Aequalis stem, followed a mean of 8.2 years. Level IV.
Key Findings
Proximal humeral osteolysis of the greater tuberosity and/or calcar appeared in 169 of 395 shoulders (43%), all after TSA. No hemiarthroplasty showed osteolysis.
Osteolysis was most frequent with an uncemented metal‑backed glenoid (48 of 79) or a cemented flat‑backed glenoid (52 of 89).
Shoulders with osteolysis had a lower mean Constant score (55 vs 67), elevation (125° vs 144°) and external rotation (26° vs 37°), all p < 0.001. These were univariate comparisons only.
Osteolysis was more common with glenoid loosening and with polyethylene wear in metal‑backed glenoids (both p < 0.001). With no glenoid cement in these shoulders, the authors suggest polyethylene particles are more likely responsible than cement.
Stress shielding occurred only around uncemented stems, all as internal remodeling (65 of 103). It was not associated with worse clinical outcome or glenoid loosening.
No uncemented stem loosened. One cemented stem was judged at risk, and another loosened 2 years after ORIF of a periprosthetic fracture.
Authors' conclusion
Glenoid issues have a substantial effect on humeral bone in shoulder arthroplasty. Polyethylene wear appears to be associated with the development of osteolysis of the proximal part of the humerus after total shoulder arthroplasty. With our implants, stress-shielding was only observed with uncemented humeral stems. The uncemented and cemented stem designs analyzed in this study appeared comparable and can be recommended for clinical use.
Raiss and colleagues described the radiographic changes that develop around one tapered humeral stem across six shoulder arthroplasty configurations, and how those changes relate to clinical outcome.
Retrospective series from 5 shoulder centers, 1991 to 2007: 395 shoulders with primary osteoarthritis, all with the Aequalis stem, followed a mean of 8.2 years. Level IV.
Key Findings
Proximal humeral osteolysis of the greater tuberosity and/or calcar appeared in 169 of 395 shoulders (43%), all after TSA. No hemiarthroplasty showed osteolysis.
Osteolysis was most frequent with an uncemented metal‑backed glenoid (48 of 79) or a cemented flat‑backed glenoid (52 of 89).
Shoulders with osteolysis had a lower mean Constant score (55 vs 67), elevation (125° vs 144°) and external rotation (26° vs 37°), all p < 0.001. These were univariate comparisons only.
Osteolysis was more common with glenoid loosening and with polyethylene wear in metal‑backed glenoids (both p < 0.001). With no glenoid cement in these shoulders, the authors suggest polyethylene particles are more likely responsible than cement.
Stress shielding occurred only around uncemented stems, all as internal remodeling (65 of 103). It was not associated with worse clinical outcome or glenoid loosening.
No uncemented stem loosened. One cemented stem was judged at risk, and another loosened 2 years after ORIF of a periprosthetic fracture.
Authors' conclusion
Glenoid issues have a substantial effect on humeral bone in shoulder arthroplasty. Polyethylene wear appears to be associated with the development of osteolysis of the proximal part of the humerus after total shoulder arthroplasty. With our implants, stress-shielding was only observed with uncemented humeral stems. The uncemented and cemented stem designs analyzed in this study appeared comparable and can be recommended for clinical use.