A silver-containing hydroxyapatite (Ag-HA) coating has been developed using thermal spraying technology. We evaluated the osteoconductivity of this coating on titanium (Ti) implants in rat tibiae in relation to bacterial infection in joint replacement. At 12 weeks, the mean affinity indices of bone formation of a Ti, an HA, a 3%Ag-HA and a 50%Ag-HA coating were 97.3%, 84.9%, 81.0% and 40.5%, respectively. The mean affinity indices of bone contact of these four coatings were 18.8%, 83.7%, 77.2% and 40.5%, respectively. The indices of bone formation and bone contact around the implant of the 3%Ag-HA coating were similar to those of the HA coating, and no significant differences were found between them (bone formation, p = 0.99; bone contact, p = 0.957). However, inhibition of bone formation was observed with the 50%Ag-HA coating. These results indicate that the 3%Ag-HA coating has low toxicity and good osteoconductivity, and that the effect of silver toxicity on osteoconductivity depends on the dose.
We hypothesised that adjuvant intermittent pneumatic
compression (IPC) beneath a plaster cast would reduce the risk of
deep-vein thrombosis (DVT) during post-operative immobilisation
of the lower limb. Of 87 patients with acute tendo Achillis (TA)
rupture, 26 were prospectively randomised post-operatively after
open TA repair. The treatment group (n = 14) received two weeks of
IPC of the foot for at least six hours daily under a plaster cast.
The control group (n = 12) had no additional treatment. At two weeks
post-operatively all patients received an orthosis until follow-up
at six weeks. At two and six weeks the incidence of DVT was assessed
using colour duplex sonography by two ultrasonographers blinded
to the treatment. Two patients withdrew from the study due to inability
to tolerate IPC treatment. An interim analysis demonstrated a high incidence of DVT in both
the IPC group (9 of 12, 75%) and the controls (6 of 12, 50%) (p
= 0.18). No significant differences in incidence were detected at
two (p = 0.33) or six weeks (p = 0.08) post-operatively. Malfunction
of the IPC leading to a second plaster cast was found to correlate
with an increased DVT risk at two weeks (φ = 0.71; p = 0.019), leading
to a premature abandonment of the study. We cannot recommend adjuvant treatment with foot IPC under a
plaster cast for outpatient DVT prevention during post-operative
immobilisation, owing to a high incidence of DVT related to malfunctioning
of this type of IPC application. Cite this article:
