Influence of Femoral Stem Geometry on Total Hip Replacement: A Comparison of Clinical Outcomes of a Straight and an Anatomical Uncemented Stem

Background/Objectives: There are many aspects that may influence clinical outcomes in a total hip arthroplasty (THA). The influence of femoral stem on the clinical outcome of THA is probably underestimated in the literature. Our work aims to analyze how uncemented stem geometry (straight or anatomical) in THA might affect outcomes in clinical and radiographic terms. Methods: Over a period of 36 months, in a prospective-observational manner, we collected the results of THA secondary to osteoarthritis (OA) that met the inclusion criteria with the only variable being the straight or anatomical stem design in a single manufacturer. A total of 84 patients were selected and divided into two groups: group A, treated with straight stem (44 patients), and group B, treated with anatomical stem (40 patients). The assessment clinical tools were Harris Hip Score (HHS), Visual Analogue Scale (VAS), and Short Form Health Survey-36 (SF-36). Follow-up controls were at 6 months (T0), 12 months (T1), 24 months (T2), and 36 months (T3). Results: No statistically significant differences emerged between the two groups under analysis with VAS, SF-36, and HHS. At follow-up controls, eight patients (group A) and four patients (group B) showed anterior thigh pain. At T1, there were radiographic signs of aseptic loosening in two cases (group A) and one case (group B). In group A there were two cases of iatrogenic fracture, two cases of dislocation, one case of infection, and two cases of heterotopic ossification. Conclusions: The anatomical stem compared to the straight stem showed lower complication rates outcomes; the anatomical uncemented stem could be considered as a preferred first choice in THA compared to the straight stem.