Innmann MM, et al. - In the present retrospective diagnostic cohort study, researchers examined the differences in clinical outcome, thigh pain and stem survival for patients with and without cortical hypertrophies (CHs) and identified patient and surgery-related factors being associated with the development of CHs. The study sample consisted of a consecutive series of 233 patients with 246 cementless total hip arthroplasties from a single academic institution. After a mean of 7.7 years, cortical hypertrophies were observed in 56% of the hips, compared to 53% after 3.3 years being mostly located in Gruen zone 3 and 5. Compared to the short-term with the present cementless short hip stem design, the percentage of cortical hypertrophies remained almost constant in the mid-term. In the mid-term, the high percentage of cortical hypertrophies does not appear to be a cause of concern for this particular implant. The only risk factor associated with the development of CHs in the regression model was the postoperative increase in hip offset.