Calcar-guided short stems in total hip arthroplasty. Why? For whom? How?

Background: Total hip arthroplasty (THA) is increasingly performed in younger, more active patients, necessitating surgical techniques that prioritize bone preservation and facilitate potential future revisions. While conventional stems are successful, they may lead to stress shielding, diaphyseal bone loss, and challenges during implant extraction.

Objective: This article evaluates the clinical rationale, anatomical restoration capabilities, and surgical techniques associated with calcar-guided short stems, specifically focusing on the Optimys system.

Key Points: Calcar-guided short stems utilize a metaphyseal anchoring philosophy to preserve bone stock in the diaphysis, greater trochanter, and femoral neck. By following the medial femoral curvature, these implants allow for more accurate restoration of native neck-shaft angles, femoral offset, and anteversion compared to straight stems. Clinical advantages include a reduction in distal femoral pain and decreased stress shielding due to more physiological proximal load transfer. However, the technique is demanding, requiring precise preoperative 3D planning and a specific learning curve. Limitations exist in patients with poor bone quality (Dorr Type C) or significant acetabular dysplasia, where valgus stem positioning may complicate offset compensation. Reported 10-year revision rates for these implants are approximately 4.8%, demonstrating long-term stability.

Conclusion: Calcar-guided short stems represent a bone-conserving alternative to conventional THA that optimizes anatomical restoration and reduces specific femoral complications. Success depends on appropriate patient selection, rigorous preoperative planning, and mastery of the metaphyseal compaction technique to ensure primary stability and optimal intramedullary filling.