Humeral osteolysis after reverse shoulder arthroplasty using cemented or cementless stems Comparative retrospective study with a mean follow-up of 9 years.

Abstract Introduction: The cause of proximal humeral osteolysis after reverse shoulder arthroplasty (RSA) remains controversial. The primary objective of our study was to compare the radiographic outcomes of Grammont-type RSA when a cemented stem is used versus when a cementless stem is used. The secondary objective was to identify the cause of these radiographic changes, especially for the cementless stems. Hypothesis: More proximal humerus bone loss occurs when a cementless humeral stem is used. Methods: With a minimum follow-up of 5 years, two paired cohorts were compared retrospectively: 70 RSA with cemented stem and 70 RSA with cementless stem. Using the radiographs made at the final follow-up visit, we looked for tuberosity resorption, signs of stress shielding, the presence of periprosthetic radiolucent lines and scapular notching. Results: At a mean follow-up of 9 years (5.0–20.6), the RSA revision rate was 1.8% in the cemented group and 3.6% in the cementless group (p = 1). Tuberosity resorption was twice as common in the cementless group: 59% versus 30% (p  Discussion: For the cementless stems, proximal humeral osteolysis can in part be attributed to stress shielding. The relationship between notching and tuberosity resorption in the two groups also suggests a secondary biological cause. Level of evidence: III; comparative retrospective study