Comparative study of fitmore and CLS stems in total hip arthroplasty: midterm clinical and radiographic outcomes

Short-stem implants offer several advantages, including the preservation of bone stock and a physiological load transfer in the subtrochanteric area. The aim of this study was to compare the radiological and functional outcomes of short stem and traditional stem during midterm follow-up. We conducted a retrospective analysis of a consecutive series of 50 patients with Fitmore and CLS stems. Clinical assessment was performed by Harris hip score; additionally, thigh pain was assessed at six months, one year, and the latest follow-up. The following radiological parameters were evaluated: stem alignment, presence of radiolucent lines and osteolysis around the stem, stem subsidence, cortical hypertrophy, femoral stress-shielding, pedestal formation at the tip of the stem, calcar resorption, heterotopic ossification, and implant loosening. The mean follow-up duration was 8.4 ± 2.1 years in the CLS group and 7.6 ± 2.2 years in the Fitmore group. The mean HHS improved from 43.0 ± 3.3 to 93.2 ± 2.5 for the CLS group and from 43.2 ± 4.4 to 93.6 ± 3.2 for the Fitmore group, without any statistical differences between the two groups. Thigh pain disappeared in all patients in the Fitmore group, while it persisted in 8% of the patients in the CLS group. There was a significant difference in the level of cortical hypertrophy between the two groups, with 28% in the Fitmore group compared to 12% in the CLS group. No statistically significant difference was observed for other radiological parameters. Both short stems and standard stems demonstrated stable fixation and satisfactory clinical and radiological outcomes.