The use of polymethylmethacrylate (PMMA) bone cement loaded with antibiotics has become increasingly common in orthopaedic surgery. However, bacterial resistance in antibiotics is an increasing and emerging problem. PMMA bone cements containing different antibiotics, such as gentamicin plus vancomycin may be effective in prevention and treatment of infections (particularly from MRSA and MRSE). The purpose of this study was to determine the in vitro elution characteristics of gentamicin and vancomycin when combined in acrylic cement. Three groups of ten cement disks were prepared. Group I (control group) contained 0.5g of gentamicin per 40-g packet of Palacos-R+G powder. Group II contained 0.5g of gentamicin and 1g of powdered vancomycin and group III contained 0.5g of gentamicin and aqueous solution of vancomycin. Each cement disc (25mm x 20mm) was immersed in a 50-mL bath of normal saline at 37oC. Samples were taken at specific sampling intervals (1, 3, 7, 15, 30, 60, 90, 120, 150, 180 days). Antibiotic concentrations were measured using fluorescence polarisation immunoassay. With regards to gentamicin release, high but rapidly decreasing antibiotic levels were detected within the first week and low concentration after the first month. Samples from Group II eluted significantly more gentamicin (120%–20% during the first month). The influence on the gentamicin release was significant but minor when aqueous solution of vancomycin (Group III) was added. With regards to vancomycin release, high antibiotic levels were detected within the first 3 days and low concentrations after the first week. Cement samples from Group II eluted significantly more antibiotic in comparison with samples from Group III. Bone cements loaded with combinations of gentamicin and vancomycin are more effective in releasing gentamicin than bone cements with gentamicin as a single drug. Powdered vancomycin in cement samples has better elution characteristics in comparison with aqueous solution of vancomycin.
i) powdered vancomycin or teicoplanin, ii) aqueous solution of vancomycin or teicoplanin.
With regards to samples from Groups IV and V (aqueous solutions of antibiotics) mechanical properties were significant deteriorated in comparison with cement samples from the other groups.
Aqueous solutions of antibiotics must not be added to the bone cement because they dramatically impair mechanical properties of the cement.
Percutaneous vertebroplasty is an effective procedure for the treatment of osteoporotic vertebral compression fractures, spinal metastasis and other pathologic spinal diseases. However, there has been no mention in the relevant literature of the use of percutaneous vertebroplasty for the treatment of spinal pseudarthrosis in ankylosing sponyloarthritis. A 58-year-old male with a long standing ankylosing spondylitis presented with increasing, intolerable and non-intractable back pain. There was a 16- month-old history of a non-significant minor fall. Various radiological imaging technicques showed spinal pseudarthrosis with extensive discovertebral destruction and fracture of the posterior elements at the level T11–T12. Under local anaesthesia, and through a transpedicular approach with the guidance of CT, the cannula of a large bore needle was introduced into the level of spinal pseudarthrosis. Bone cement was then instilled into the affected spinal level. Results were documented by spiral CT and with sagittal reconstructions. Extraosseous cement leakage was seen at the puncture site of the vertebra and in the epidural veins and the paravertebral vessels. However, the patient did not present any immediate or late neurological and systemic complications. Percutaneous vertebroplasty of spinal pseudarthrosis in patients with ankylosing spondylitis is an effective procedure for stabilization of the affected spine segments and pain management.
The aim of this paper is to present our experience from the surgical treatment of lower limb fractures in the developing skeleton with the use of bio-absorbable PLLA implants as a means of internal fixation. From 1997 until 2002, twenty-three patients (15 boys and 8 girls, ages ranging from 7 to 15 years old, mean of 12 years) who had suffered from 30 lower limb fractures were operated on in our department, with the use of PLLA screws as a means of internal fixation that followed the standard open reduction procedure. We surgically treated 20 tibial fractures (distal metaphysis:1,medial malleolar:6,distal epiphysis lesions:9,tibial spine:2, lateral tibial condyle:1, tibial shaft:1), 8 fibular fractures (distal metaphysis:2, distal epiphysis lesions:5, fibular shaft:1), one transtrochanteric fracture and 1 patellar fracture. All patients were operated on under constant radiographic control. A cast was applied, post-operatively, to all patients, for a period of 3–4 weeks. Gradual and assisted weight-bearing and ambulation, was commencing immediately after the cast removal. All patient’s (with the exception of 1 case of delayed callus formation) post-operative period was completely normal. However, follow-up revealed the development of osteolytic lesions (bone absorption cysts) in 3 of our patients. All lesions were located in the border between epiphysis and metaphysis, at the exact position were the PLLA screws had been placed. The use of PLLA implants in the treatment of fractures renders unnecessary a second operation for the removal of the osteosynthesis’ material. Nevertheless, we should be quite reluctant when deciding to use the PLLA screws in the treatment of these fractures in the developing skeleton, especially of the lower limbs, were the applied weight bearing forces are quite powerful.