Staphylococcus aureus is responsible for 60–70% infections of surgical implants and prostheses in Orthopaedic surgery, costing the NHS £120–200 million per annum. Its ability to develop resistance or tolerance to a diverse range of antimicrobial compounds, threatens to halt routine elective implant surgery. One strategy to overcome this problem is to look beyond traditional antimicrobial drug therapies and investigate other treatment modalities. Biophysical modalities, such as ultrasound, are poorly explored, but preliminary work has shown potential benefit, especially when combined with existing antibiotics. Using a methicillin-sensitive S. aureus reference strain and the dissolvable bead assay, biofilms were challenged by a low-intensity ultrasound (1.5MHz, 30mW/cm2, pulse duration 200µs/1KHz) for 20 minutes and gentamicin. The outcome measures were colony-forming units/mL (CFU/mL) and the minimum biofilm eradication concentration (MBEC) of gentamicin. The mean number of S. aureus within control biofilms was 1.04 × 109 CFU/mL. There was no clinically or statistically significant (p=0.531) reduction in viable S. aureus following ultrasound therapy alone. The MBEC of gentamicin for this S. aureus strain was 256 mg/L. The MBEC of gentamicin with the addition of ultrasound was 64mg/L. Further studies confirmed that the mechanism of action was due to incomplete disruption of the extracellular matrix with subsequent metabolic stimulation of the dormant biofilm-associated bacteria due to increased nutrient availability and oxygen tension. Low intensity pulsed ultrasound was associated with a 4-fold reduction in the effective biofilm eradication concentration of gentamicin; bringing the MBEC of gentamicin to within clinically achievable concentrations.
The aim of this double-blind prospective randomised controlled
trial was to assess whether low intensity pulsed ultrasound (LIPUS)
accelerated or enhanced the rate of bone healing in adult patients
undergoing distraction osteogenesis. A total of 62 adult patients undergoing limb lengthening or bone
transport by distraction osteogenesis were randomised to treatment
with either an active (n = 32) or a placebo (n = 30) ultrasound
device. A standardised corticotomy was performed in the proximal
tibial metaphysis and a circular Ilizarov frame was used in all
patients. The rate of distraction was also standardised. The primary
outcome measure was the time to removal of the frame after adjusting
for the length of distraction in days/cm for both the per protocol
(PP) and the intention-to-treat (ITT) groups. The assessor was blinded
to the form of treatment. A secondary outcome was to identify covariates affecting
the time to removal of the frame.Aims
Patients and Methods
Despite proven advantages, pulsatile lavage seems to be used infrequently during preparation in cemented total knee arthroplasty. This remains irritating, as the technique has been suggested to improve radiological survival in cemented TKA, where aseptic loosening of the tibial component represents the main reason for revision. Furthermore, there may be a potential improvement of fixation strength for the tibial tray achieved by increased cement penetration. In this study, the influence of pulsed lavage on mechanical stability of the tibial component and bone cement penetration was analyzed in a cadaveric setting. Six pairs of cadaveric, proximal tibia specimen underwent computed tomography (CT) for assessment of bone mineral density (BMD) and exclusion of osseous lesions. Following surgical preparation, in one side of a pair, the tibial surface was irrigated using 1800ml normal saline and pulsatile lavage, while in the other side syringe lavage using the identical amount of fluid was applied. After careful drying, bone cement was hand-pressurized on the bone surface, tibial components were inserted and impacted in an identical way. After curing of cement, specimen underwent a postimplantation CT analysis). Cement distrubution was then assessed using a three-dimenionsional visualization software. Trabecular bone, cement and implant were segmented based on an automatic thresholding algorithm, which had been validated in a previous study. This allowed to determine median cement penetration for the entire cemented area. Furthermore, fixation strength of the tibial trays was determined by a vertical pull-out test using a servohydraulic material testing machine. Testing was performed under displacement control at a rate of 0,5mm/sec until implant failure. Data was described by median and range. Results were compared by a Wilcoxon matched pairs signed rank test with a type 1 error probability of 5 %. Median pull-out forces in the pulsed lavage group were 1275N (range 864–1391) and 568N (range 243–683) in the syringe lavage group (p=0.031). Cement penetration was likewise increased (p=0.031) in the pulsed lavage group (1.32mm; range 0.86–1.94), when compared to the syringe irrigated group (0.79mm; range 0.51–1.66). Failure occurred in the pulsatile lavage group at the implant-cement interface and in the syringe lavage group at the bone-cement interface, which indicates the weakness of the latter. Altogether, improved mechanical stability of the tibial implant and likewise increased bone cement interdigitation could be demonstrated in the current study, when pulsed lavage is implemented. Enhanced fixation strength was suggested being a key to improved survival of the implant. If this is the case, pulsatile lavage should be considered being a mandatory preparation step when cementing tibial components in TKA.
We conducted a multicentre two arm double blind randomised controlled trial to assess efficacy of pulsed ultrasound for accelerating the rate of bone healing. Sixty-two skeletally mature adults undergoing limb lengthening, of between 2.5cm to 10cm by distraction osteogenesis, at the proximal tibia using an Ilizarov frame were randomised to either an active or a placebo (control) ultrasound device. Primary outcome measure was time ready for removal of frame after adjusting for distraction length (days/cm) for both intension to treat (ITT) and per protocol (PP) patients. The time at which the frame was removed was determined by the maturation of the regenerate bone. Secondary outcomes were return to weight bearing and covariates affecting time to frame removal. The baseline characteristics of the two groups were well balanced, and 90% of patients were managed and followed up as PP. There was no difference in the time to frame removal between the two groups for the ITT (5.0days/cm, p=0.23) or the PP (10.1days/cm, p=0.054). There was no difference in return to weight bearing between the two groups, after adjusting for distraction length, for the ITT or PP patients (p>0.5). Smoking was the only covariate identified to increase the frame removal time (hazard ratio 0.46, 95% confidence interval 0.22 to 0.96; p=0.04). This trial demonstrated no difference in bone healing between those who underwent pulsed ultrasound and those who did not. Smoking was observed to have a significant inhibitory effect on bone healing.
To assess efficacy of pulsed ultrasound for accelerating regenerate consolidation. A multicentre two arm patient and assessor double blind RCTObjective:
Design:
To determine what factors affect fracture healing with low-intensity pulsed ultrasound (LIPUS) for delayed unions and nonunions. A consecutive cohort of 101 delayed unions and 50 nonunions after long bone fractures treated with LIPUS between May 1998 and April 2007.Objective
Patients
Low-intensity pulsed ultrasound (LIPUS) has been reported to enhance healing of fracture and nonunion. Bone morphogenetic protein-7 (BMP-7) has also been reported to promote bone formation. Recently, we demonstrated progenitor cells with osteogenic/chondrogenic differentiation potential existed in human fracture hematoma and nonunion tissue. We hypothesised the combined application of LIPUS and BMP-7 would cause major effect on osteogenesis of hematoma-derived cells (HCs) and nonunion tissue-derived cells (NCs).Introduction
Hypothesis
Delayed onset muscle soreness (DOMS) in the quadriceps is frequent in runners finishing a marathon race, and may result in several days of discomfort and pain. There is an increasing clinical evidence that noninvasive, pulsed electromagnetic field therapy (PEMF) can have physiological effect on inflammation and tissue repair. The purpose of this pilot study was to investigate the effect of PEMF on quadriceps muscle soreness in marathon runners and to use the data to calculate an appropriate sample size for a subsequent study. The design was a randomized double-blind prospective study covering a 5 days period after completion of a beach marathon. After the marathon all 74 runners that completed the 42.195 km were asked to participate in the study. Forty-six agreed to enter the study and were block randomized into an intervention group or a control group. The intervention group received an active pulsed electromagnetic field device, and the control group received a sham device. The sham devices were used in exactly the same manner but produced no electromagnetic field. The active PEMF device does not produce heat or cause any sensation in the tissue allowing participants to be blinded to treatment. The pulsed electromagnetic field signals of a 2-msec burst of 27.12-MHz sinusoidal waves were repeated at two bursts per second. Peak magnetic field was 0.05 G, which induced an average electric field of 10 mV/cm in the tissue with an effect of 7.3 mW/cm3. All subjects were instructed to place the device on the most painful area of the quadriceps for 20 minutes four times a day. Pain intensity was measured three times a day with the Visual Analogue Scale (VAS) during a 90o squat with a self-administered questionnaire. Data were non-parametric and compared with a two-sample Wilcoxon rank-sum test.Introduction
Material and methods
Introduction. Nonunions pose complications in fracture management that can be treated using electrical stimulation (ES). Bone marrow mesenchymal stem cells (BMMSCs) are essential in fracture healing, although the effects of different clinical ES waveforms available in clinical practice on BMMSCs cellular activities is unknown. Materials and Methods. We compared Direct Current (DC), Capacitive Coupling (CC),
