Recent Advances in Clinical Trials
Open AccessFluid–thermal Control of PMMA Cementation for Long Femoral Stems
Authors: Chi-Ming Chiang.
Abstract
Background: PMMA cementation couples time-dependent, non-Newtonian flow with exothermic polymerization. Long femoral stems challenge mantle control because viscosity rise, canal pressurization, and insertion kinematics must be coordinated over a larger cement volume while maintaining a conservative thermal window.
Methods: We implemented a fluid–thermal control law (μ–Δp–U–δ) emphasizing early low-viscosity continuous pressurization with proximal sealing, an isovelocity stem-insertion trajectory, and δ-guided mantle balancing using surgeon-observable resistance/back-pressure cues. Postoperative radiographs were graded for cement quality (Barrack; Gruen zones) and calibrated mantle thickness, with an a priori target of 2–4 mm.
Results: The cement mantle was continuous (Barrack A–B on AP and B on lateral) with no radiolucent lines >1 mm. Calibrated mantle thickness was predominantly within the 2–4 mm target band, with a focal maximum of 7.5 mm; no periprosthetic fracture occurred.
Conclusion: Framing cementation as a coupled fluid–thermal control problem provided a practical pathway to achieve a high-quality mantle in a long-stem construct. Thermal risk was constrained by design (pre-cooling, sustained pressure plateau, and avoidance of thick cement pockets) relative to a conservative ≈47 °C × 60 s criterion, motivating prospective validation with intraoperative pressure/temperature logging.
Translational potential of this article: A low-dimensional control law—operationally visible to surgeons as timing (μ), steadiness (Δp), and kinematics (U), with δ as a proxy for thickness uniformity—can steer cementation toward a reproducible 2–4 mm mantle even for long stems. The framework is directly testable with intraoperative pressure/ temperature logging and bench thermal characterization.
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