Excellent long-term outcomes with an anatomic cementless stem (SPS Evolution) designed using a CT-scan database and inserted with 3D CT-scan preoperative planning: A prospective cohort study

Orthop Traumatol Surg Res. 2025 Apr 14:104245. doi: 10.1016/j.otsr.2025.104245. Online ahead of print.

ABSTRACT

BACKGROUND: Recently, improved hip reconstruction accuracy after total hip arthroplasty (THA) was reported with a specific anatomic stem featuring helicoidal torsion and a double sagittal curvature (SPS Evolution™), compared to the standard double-tapered straight stem, which remains the most widely used design globally. However, no studies have analyzed the ten-year outcomes of THA using this stem. The objective of this study was to assess the survivorship of SPS Evolution™ at ten-year follow-up.

HYPOTHESIS: The use of the modified SPS Evolution™ design provides excellent long-term fixation, a low risk of stress shielding and thigh pain, and a reduced dislocation rate.

MATERIAL AND METHODS: A prospective cohort study included 134 consecutive patients who underwent surgery between December 2011 and December 2013. An anatomic stem (SPS Evolution™) with exclusive proximal surface treatment, a cementless acetabular component, and a Delta ceramic-ceramic bearing couple were used in all patients. In total, 102 patients (118 hips), with a mean age of 60 ± 11 years (range, 32-83 years), were evaluated after an average follow-up of 10.6 ± 0.6 years (range, 10-12 years), using the Harris Hip Score (HHS) and the Oxford Hip Score (OHS) self-assessment questionnaires. The fixation and stability of the femoral stem were assessed using the Engh and ARA scores.

RESULTS: An early femoral revision was performed on a 69-year-old woman following a post-traumatic femoral fracture. With aseptic loosening as the endpoint, the survival rate was 100% in 118 hips (95% CI, 96.7-100%) at 10 years. Excellent clinical outcomes were observed, with a mean HHS score of 97.6 ± 6.2 (range, 69-100) and an OHS score of 44.9 ± 5.2 (range, 23-48). All stems were found to be stable and well-osseointegrated.

DISCUSSION: The SPS Evolution™ stem demonstrated an excellent ten-year survival rate. In addition to precise hip reconstruction, it provided excellent clinical and radiological outcomes, indicating that the SPS Evolution™ is a reliable and "conservative" implant.

LEVEL OF EVIDENCE: IV, prospective cohort study without control group.

PMID:40239918 | DOI:10.1016/j.otsr.2025.104245