ABSTRACT
The authors describe a surgical procedure to 'fine-tune' the tibial slope during high-tibial osteotomy. Fifteen consecutive patients were treated for medial compartment osteoarthritis of the knee using a temporary unilateral external fixator and accompanying internal fixator composed of two plates (with different sized space). All 15 patients were evaluated by measuring femoro-tibial angles (FTAs) in the frontal plane, and using the proximal tibial anatomical axis (PTAA) and the posterior tibial cortex (PTC) methods to assess tibial slope in the sagittal plane. FTA, PTAA, and PTC angles were measured using: (1) radiographs taken before surgery, (2) fluoroscopic images taken after inserting the first plate during surgery, (3) fluoroscopic images taken after tibial slope restoration using an external fixator system during surgery, and finally using, (4) radiographs taken after surgery. In all patients, preoperative PTAA and PTC angles increased significantly after inserting the first plate posteromedially at osteotomy site. After tibial slope had been accurately restored using the external fixator system, PTAA and PTC angles decreased to the preoperative tibial slope level without changing femorotibial angles in the coronal plane. The authors were able to acquire a consistent and reproducible natural tibial slope using tibial slope "fine tuning" using an external fixator and a stable internal fixator.
Subject(s)
External Fixators , Osteoarthritis, Knee/surgery , Osteotomy/methods , Tibia/surgery , Female , Humans , Internal Fixators , Knee Joint/anatomy & histology , Male , Middle Aged , Tibia/anatomy & histologyABSTRACT
A simple, fast and sensitive high-performance liquid chromatography (HPLC)-electrospray ionization (ESI) tandem mass spectrometric method (LC-MS/MS) has been developed for determination of propiverine and propiverine N-oxide metabolite in human plasma using oxybutynin as internal standard. Instead of extracting propiverine from plasma using organic solvents, which should be separated from the aqueous phase and evaporated before injecting the sample into the chromatograph, plasma sample containing propiverine and N-oxide was directly injected after precipitating proteins with acetonitrile. Numerous compounds in the plasma did not interfere with the highly specific multiple reaction monitoring in tandem mass spectrometric detection following C(8) reversed-phase chromatographic separation under conditions that eluted propiverine, N-oxide and oxybutynin within 2min (0.1% formic acid in water/acetonitrile, 25:75, v/v). The LC-MS/MS method and an alternative LC-MS method, using methyl-t-butyl ether extraction and selected ion monitoring, were validated over 1-250ngml(-1) of propiverine and 2 to 500ngml(-1) of N-oxide, and successfully applied in a pharmacokinetic study. The lower limit of quantitation was 1ngml(-1) for propiverine and 2ngml(-1) for N-oxide in both methods.
ABSTRACT
A simple, fast and sensitive high-performance liquid chromatography (HPLC)-mass spectrometric (MS) method has been developed for simultaneous determination of amoxicillin and clavulanic acid in human plasma using terbutaline as internal standard. After precipitation of the plasma proteins with acetonitrile, the analytes were separated on a C(8) reversed-phase column with formic acid-water-acetonirile (2:1000:100) and detected using electrospray ionization (ESI) mass spectrometry in negative selected ion monitoring (SIM) mode. The method was validated and successfully applied to analysis of amoxicillin and clavulanic acid in clinical studies. The limit of quantitation, 0.12 microg/ml for amoxicillin and 0.062 microg/ml for clavulanic acid, was five times lower than that of the published HPLC-UV method.
