Serum kinetics of soluble triggering receptor expressed on myeloid cells-1 differs in relation to the type of arthroplasty.

CONTEXT: Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) participates in the inflammatory process. PURPOSE: To describe changes of sTREM-1 in the serum after hemiarthroplasty (HA) and total hip arthroplasty (THA). METHODS: Serial blood samples were drawn from 122 patients with hip fracture. Interleukin-6 (IL-6), sTREM-1, and C-reactive protein (CRP) were measured. RESULTS: IL-6 and CRP were similarly increased after both HA and THA. sTREM-1 was increased early in HA and late after THA. The only parameter that was higher among patients who developed systemic inflammatory response syndrome was IL-6. CONCLUSIONS: Kinetics of sTREM-1 differs among patients undergoing HA of the hip and those undergoing THA.

Experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus treated with a polylactide carrier releasing linezolid.

BACKGROUND: The effectiveness of a new delivery system consisting of polymerized dilactide (PLA) with incorporated linezolid was investigated in a rabbit model as a means of treating methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis. METHODS: The PLA-linezolid system was prepared after thorough stirring of PLA with linezolid at a 10:1 ratio. Experimental osteomyelitis was established in 40 rabbits by a modification of the Norden model with MRSA as the test isolate. After a hole had been drilled in the upper right femur, the isolate was inoculated using a thin needle working as a foreign body. At three weeks, the needle was removed and cultured, and the PLA-linezolid system was implanted in half the animals (group B); the remaining half was the control group (group A). Animals were sacrificed at regular intervals; tissue around the site of implantation was examined for pathologic changes and cultured quantitatively. RESULTS: The prepared system eluted linezolid in vitro at concentrations much greater than the minimum inhibitory concentration (MIC) of the test pathogen for 11 days. At three weeks after inoculation of the test isolate, all animals had osteomyelitis. By the sixth week, bacterial growth from cancellous bone of group B was significantly lower than that in group A. However, this effect was not maintained until the end of the study (weeks 8 and 10), when the differences in bacterial growth in the two groups were not significant. CONCLUSION: Polymerized dilactide mixed with 10% linezolid achieved partial arrest of the offending pathogen in an experimental model of osteomyelitis caused by MRSA.

Finite element method in internal and hybrid external fixation of tibial condylar fractures: a comparative application study.

The treatment of tibial condylar fractures requires the preparation of personalized treatment, customized to the needs of the patient, that will take into consideration his or her personal activities. The purpose of the present study was (1) the development, by using the finite elements method, of a 3-dimensional, highly discrete, simulation model of the knee-tibia, (2) the creation of 6 types of fractures in this model according to Schatzker's classification, (3) the insertion of materials for internal and hybrid external fixation, (4) the recording of the model's biomechanical behavior during the load, and (5) the discovery of findings regarding the stability of the internal and hybrid external treatment methods. The results from the resolution procedure showed that the values of maximum displacements in every fracture type except type III were reduced in the models with internal fixation. This means decreased stiffness and therefore diminished stability of the hybrid external-bone complex in these types of fractures. Internal fixation provides postoperative stability, a basic precondition for accelerated fracture healing.