BackgroundPatients post total hip arthroplasty (THA) remain at high risk of developing Deep Vein Thrombosis (DVT) during the recovery period following surgery despite the availability of effective pharmacological and mechanical prophylactic methods. The use of calf muscle neuromuscular electrical stimulation (NMES) during the hospitalised recovery period on this patient group may be effective at preventing DVT. However, the haemodynamic effectiveness and comfort characteristics of NMES in post-THA patients immediately following surgery have yet to be established.MethodsThe popliteal veins of 11 patients, who had undergone unilateral total hip replacement surgery on the day previous to the study, were measured using Doppler ultrasound during a 4 hour neuromuscular electrical stimulation (NMES) session of the calf muscles. The effect of calf muscle NMES on peak venous velocity, mean venous velocity and volume flow were compared to resting values. Comfort was assessed using a 100mm non-hatched visual analogue scale taken before application of NMES, once NMES was initiated and before NMES was withdrawn.ResultsIn the operated limb NMES produced increases in peak venous velocity of 99% compared to resting. Mean velocity increased by 178% compared to resting and volume flow increased by 159% compared to resting. In the un-operated limb, peak venous velocity increased by 288%, mean velocity increased by 354% and volume flow increased by 614% compared to basal flow (p<0.05 in all cases). There were no significant differences observed between the VAS scores taken before the application of NMES, once NMES was initiated and before NMES was withdrawn (p=.211).ConclusionsNMES produces a beneficial hemodynamic response in patients in the early post-operative period following orthopaedic surgery. This patient group found extended periods of calf-muscle NMES tolerable.Trial registrationClinicalTrials.gov NCT01785251

In view of the importance placed on the first intermetatarsal angle in the assessment of surgical intervention in hallux valgus, we assessed the reliability with which one measures this angle. The study involved 10 observers of varying experience measuring the angle using a standard technique on 10 weightbearing AP X-rays of the foot on three separate occasions. The margin of error in measuring the angle was +/-3.60 degrees with a 95% confidence interval. Increasing and averaging the number of readings per observer or the readings of a number of observers, reduces the error. Experience doesn't improve reliability. In conclusion, improvement in the reliability of the measurements can be achieved by careful technique, performing the measurements at least twice, and averaging them.

IntroductionThe objective of this study was to determine if a synthetic bone substitute would provide results similar to bone from osteoporotic femoral heads during in vitro testing with orthopaedic implants. If the synthetic material could produce results similar to those of the osteoporotic bone, it could reduce or eliminate the need for testing of implants on bone.MethodsPushout studies were performed with the dynamic hip screw (DHS) and the DHS Blade in both cadaveric femoral heads and artificial bone substitutes in the form of polyurethane foam blocks of different density. The pushout studies were performed as a means of comparing the force displacement curves produced by each implant within each material.ResultsThe results demonstrated that test material with a density of 0.16 g/cm3 (block A) produced qualitatively similar force displacement curves for the DHS and qualitatively and quantitatively similar force displacement curves for the DHS Blade, whereas the test material with a density of 0.08 g/cm3 (block B) did not produce results that were predictive of those recorded within the osteoporotic cadaveric femoral heads.ConclusionThis study demonstrates that synthetic material with a density of 0.16 g/cm3 can provide a good substitute for cadaveric osteoporotic femoral heads in the testing of implants. However we do recognise that no synthetic material can be considered as a definitive substitute for bone, therefore studies performed with artificial bone substrates may need to be validated by further testing with a small bone sample in order to produce conclusive results.

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