A Novel Implant Design for Cemented Endoprosthesis Stems to Reduce the Risk of Bone Cement Implantation Syndrome

Bone cement implantation syndrome (BCIS) is a life-threatening risk of cemented stems. There are limited methods to prevent BCIS and few published studies. A survey of the Musculoskeletal Tumor Society (MSTS) surgeons was conducted to evaluate their experiences with BCIS. A novel stem designed to reduce intramedullary pressure during insertion was evaluated.

A survey was distributed to MSTS members, and data was collected. The novel stem featured a hollow longitudinal channel, an entry hole at the tip, and an egress hole at the collar for cement to flow from the intramedullary canal during insertion. Bending stiffness was compared using finite element analysis to a standard solid stem. Stems were cemented into cadaveric femurs. Specimens were loaded with 8000 N tensile force and then maximally torqued until failure. Intramedullary pressures were measured for novel and standard stems cemented into sawbones.

In 107 survey responses, 58% (n = 63) experienced severe BCIS, and 83% (n = 52) of those had ≥1 death from BCIS complications. Many surgeons avoid cementing long stems, and 78% (n = 14) report concern for BCIS as the reason. Seventy-nine percent (n = 84) use an average of 4.75 different methods to reduce BCIS risk. The novel stem demonstrated 2.8% reduced bending stiffness. When cemented into cadaveric bone, both stem designs achieved 8000 N of tensile force, and there was no significant difference in torque failure (140.6 Nm in the novel stem; 128 Nm in the standard stem). The average peak pressure was significantly lower for the novel stem (77 psi vs. 151 psi).

The majority of surgeons have concerns regarding BCIS based on their experience and use multiple methods to reduce risk. A novel stem can reduce the intramedullary insertion pressure by approximately half and possibly reduce the risk of BCIS. Testing demonstrates similar stiffness and stability compared to standard solid stems.