The field of nanoparticle related research for the diagnosis and therapy of diseases evolves rapidly. Magnetic nanoparticles in combination with magnetizable implant materials for the treatment of implant related infections present a possible implementation in orthopedics. Magnetic nanoporous silica nanoparticles (MNPSNPs) were developed and equipped with fluorescent dyes. In vitro/in vivo biocompatibility and in vivo biodistribution were examined to appraise their potential applicability. Cell culture tests with NIH-3T3 and HepG2 cell lines indicated a good in vitro biocompatibility. Ferritic and titanium alloy (control) plates were implanted subcutaneously at the hind legs of Balb/c mice. Immediately after i.v. or s.c. injection of MNPSNPs, the caudal half of the mice was placed between the poles of an electro magnet. Exposure to the electromagnetic field of approx. 1.7 T was maintained for 10 minutes. 10 animals each were euthanized at days 0, 1, 7, 21 or 42, respectively. Quantity of MNPSNPs in liver, spleen, kidney, lung and skin/muscle samples was assessed by fluorescent microscopic methods. MNPSNP existence on the implant surface was also appraised after several steps of detachment. MNPSNPs showed a time-dependent accumulation in the organs after i.v. injection with initial accumulation in the lungs followed by redistribution to liver and spleen. After s.c. injection no systemic distribution but local appearance of MNPSNPs could be found. First histological evaluation showed no pathological changes after i.v. injection. With good in vivo biocompatibility, future focus will be laid on increasing circle life time of MNPSNPs and evaluation in an infection model.

Introduction: Increasing costs for health care has forced its providers to economize with current resources. This paper reports on cost analysis from a randomized study where the study group (SG) was subjected to pre-operative education and postoperative home-based rehabilitation after total hip replacement (THR). The comparison group (CG ) comprised patients treated according to routine pathway at the time.

Methods: Between 1997 and 2000 a total of 50 patients were operated on in two hospitals, 29 at the Landspíta-linn University Hospital in Reykjavík and 21 in a nearby rural hospital. They were randomized into a study group (SG) of 27 patients and control group of 23. All contacts with the health care during a six month period after the operations were registered. The effectiveness of the treatments was measured with the Oxford Hip Score (OHS).

Results: The average hospital costs totalled $5,848 in the SG and $7,291 in the CG. Total health care costs was $6,402 on average in the SG and $9,248 in the CG. By including average patient related costs the total rose to $9,570 in the SG and $13,377 in the CG (all costs in 1999 USD). The difference was statistically significant (p=0.0001) for the total costs. The group variable was statistically significant – regression analysis adjusted for age gender etc., not excluding significant factors according to the Ramsey RESET test. The recovery according to the OHS was from 33.1 preoperatively down to 14.2 after six months follow up for the study group. For the CG it was 36.6 and 20.5 respectively. Thus the cost difference (ΔC) was $3,807 and an effectiveness difference (ΔE) of 6.3. No significant difference was found in cost between hospitals, although indications favoured the rural hospital

Conclusions: Our method of shortening hospital stay and transferring parts of the postoperative treatment to the patient’s homes appears to be an effective way of reducing the unit price of THR in Iceland.