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Methylmethacrylate plasma levels during total hip arthroplasty
Abstract:
Methylmethacrylate (MMA) plasma concentrations were measured in 11 patients scheduled for total hip arthroplasty. After acetabular and after femoral cement implantation, sequential blood samples were withdrawn from pulmonary and radial artery catheters. The peak concentration of MMA (mean +/- standard error of the mean) in pulmonary artery blood occurred two minutes after cement implantation and was significantly higher after acetabulum (5.0 +/- 1.3 micrograms/ml) than after femoral cement insertion (1.9 +/- 0.6 micrograms/ml). The MMA peak in plasma was above 1 micrograms/ml in 13 cases, and the decrease fit a biexponential decay (r = 0.91). The initial half-life was 0.3 +/- 0.1 minutes, and the terminal half-life was 3 +/- 0.7 minutes. The areas under the curve (AUC) were determined for pulmonary (AUCpa) and radial (AUCra) plasma samples, and the ratio (AUCpa - AUCra)/AUCpa was computed: 55.1 +/- 7.8% of MMA was cleared during the transpulmonary passage. These results demonstrate that: (1) MMA could be determined after each cement implantation, (2) MMA plasma concentrations were higher after acetabulum than after femoral cement implantation, and (3) the half-life is short and the total pulmonary clearance is high.
Insights
Methylmethacrylate (MMA) levels peak after hip replacement surgery, with higher concentrations following acetabular implantation. The study quantifies MMA clearance, showing rapid elimination via the lungs.
Area of Science:
- Biomaterials Science
- Orthopedic Surgery
- Pharmacokinetics
Background:
- Methylmethacrylate (MMA) is a key component in bone cement used in orthopedic procedures like total hip arthroplasty.
- Understanding MMA pharmacokinetics is crucial for assessing patient safety and potential systemic effects following cement implantation.
Purpose of the Study:
- To quantify plasma concentrations of MMA after acetabular and femoral cement implantation during total hip arthroplasty.
- To determine the transpulmonary clearance and elimination half-life of MMA.
Main Methods:
- Blood samples were collected from pulmonary and radial artery catheters in 11 patients undergoing total hip arthroplasty.
- MMA concentrations were measured sequentially after acetabular and femoral cement placement.
- Analysis included peak concentrations, biexponential decay modeling, and calculation of area under the curve (AUC) for pulmonary and radial plasma samples.
Main Results:
- Peak MMA concentrations were significantly higher after acetabular (5.0 ± 1.3 µg/ml) compared to femoral (1.9 ± 0.6 µg/ml) cement implantation.
- MMA plasma levels decreased following a biexponential decay pattern with a short initial half-life (0.3 ± 0.1 min) and a terminal half-life (3 ± 0.7 min).
- Approximately 55.1 ± 7.8% of MMA was cleared during transpulmonary passage, indicating high pulmonary clearance.
Conclusions:
- MMA can be reliably measured in plasma after both acetabular and femoral cement implantation.
- Acetabular cement implantation results in higher peak MMA plasma concentrations than femoral implantation.
- MMA exhibits a short elimination half-life and significant pulmonary clearance, suggesting rapid systemic processing.