Cemented or uncemented fixation: Which allows a more acceptable prosthetic femoral version in total hip arthroplasty?

Background Three-dimensional computed-tomography (3D-CT) planning for primary Total Hip Arthroplasty (THA) typically uses the external femoral surface; as a result, it is difficult to predict the prosthetic femoral version (PFV) for uncemented femoral stems that press-fit to the internal surface of the bone. Cemented fixation allows the surgeon to adjust the version independent of the internal femoral anatomy. We aimed to better understand the effect of the fixation type on PFV.Methods This was a case series study including a total of 95 consecutive patients (106 hips), who underwent uncemented (n = 81 hips) and cemented (n = 25 hips) primary THA using the posterior approach. The surgeon aimed for a PFV of 20(degrees). Our primary objective was to compare PFV in both groups; our secondary objective was to evaluate the clinical outcomes.Results The mean (+/- SD) PFV was 13 degrees (+/- 9 degrees) and 23 degrees (+/- 8 degrees) for the uncemented and cemented THA groups (P < 0.001), respectively. In the uncemented THA group, 36% of the patients had a PFV of < 10 degrees. In the cemented THA group, this clinically important threshold dropped to 8%. Similarly, the Bland-Altman (BA) plots showed wider 95% limits of agreement for the uncemented group. Satisfactory clinical outcomes were recorded.Conclusion We found that the PFV was more clinically acceptable, for the posterior surgical approach, in the cemented group when compared to the uncemented group. Both THA groups reported high variability indicating the need to develop surgical tools to guide the PFV closer to the surgical target.