Economic advantage of 'self-made' antibiotic-loaded spacer compared to prefabricated antibiotic-loaded spacer and spacer molds in two-staged revision arthroplasty.

Infection after total hip or total knee arthroplasty is a serious complication implying great costs for the health care system. Amongst the different treatment options, the two-step exchange using a spacer in the interval is a valid option. We evaluate the economic impact of our self-made antibiotic-loaded hip and knee cement spacers compared with prefabricated spacers and spacer molds. Costs to prepare self-made cement spacers are detailed for each spacer type. We also assess the intraoperative time spent for fabricating our self-made hip and knee spacers. The price of these self-made knee spacer is 514 CHF (450 EUR / 505 USD) if non-articulated and 535 CHF (470 EUR / 525 USD) if articulated ; the price for the self-made hip spacer is 749 CHF (760 EUR / 735 USD). Our average preparation time is 14 minutes for our self-made knee spacers and 16 minutes for our self-made hip spacers. While the senior surgeon is fabricating the self-spacers, another surgeon of the team continues intensive irrigation and debridement. Thus, no time is lost waiting for the self-spacer to be fabricated. In our hands, self-made hip and knee spacers are at least 40-50% cheaper than prefabricated spacers and spacer-molds. This is a serious economic advantage in this already expensive surgery. When done in teamwork, self-spacer fabrication does not increase the surgery time. The economic advantage is added to the main and most important advantage of self- made spacers, which remains the possibility of patient adapted anatomical reconstruction of the joint.

Phosphocalcium ceramics are efficient in the management of severe acetabular loss in revision hip arthroplasties. A 22 cases long-term follow-up study.

Management of bone loss in revision total hip replacement remains a challenge. To eliminate any immunological or infectious problem and so to try to improve the long-term results obtained with allografts, the authors used synthetic ceramics as bone substitutes since 1995. We reviewed 13 of the patients of our study, we previously reported in 2005 (Schwartz and Bordei in Eur J Orthop Surg Traumatol 15: 191 2005), which was a prospective cohort of thirty-two cases of acetabular revision reconstruction, with a mean follow-up of 14.4 years yet (from 9 to 16 years). Clinical results were assessed according to Oxford scale and Postel and Merle d'Aubigne (PMA) scale. Since 2005, no specific complications were noted. The average PMA functional hip score was 14.9 (vs. 9.2 before revision) at follow-up over 9 years. Nine patients still alive in 2013 were seen again by a surgeon, which was not the operator, with a mean follow-up of 15.3 years: Their Oxford average score was 40.3. Radiological assessment affirmed a good integration of the substitutes in bone without any edging in all cases. A progressive invasion of the ceramics by bone can be seen on the X-ray. We conclude that about 15 years of average delay, which is a significant follow-up in orthopedic surgery, the outcomes without specific complications are satisfactory and allow one to go with these materials in total hip revision surgery.

Dosimetry protocol for the forthcoming clinical trials in synchrotron stereotactic radiation therapy (SSRT).

PURPOSE: An adequate dosimetry protocol for synchrotron radiation and the specific features of the ID17 Biomedical Beamline at the European Synchrotron Radiation Facility are essential for the preparation of the forthcoming clinical trials in the synchrotron stereotactic radiation therapy (SSRT). The main aim of this work is the definition of a suitable protocol based on standards of dose absorbed to water. It must allow measuring the absolute dose with an uncertainty within the recommended limits for patient treatment of 2%-5%. METHODS: Absolute dosimetry is performed with a thimble ionization chamber (PTW semiflex 31002) whose center is positioned at 2 g cm(-2) equivalent depth in water. Since the available synchrotron beam at the ESRF Biomedical Beamline has a maximum height of 3 mm, a scanning method was employed to mimic a uniform exposition of the ionization chamber. The scanning method has been shown to be equivalent to a broad beam irradiation. Different correction factors have been assessed by using Monte Carlo simulations. RESULTS: The absolute dose absorbed to water at 80 keV was measured in reference conditions with a 2% global uncertainty, within the recommended limits. The dose rate was determined to be in the range between 14 and 18 Gy/min, that is to say, a factor two to three times higher than the 6 Gy/min achievable in RapidArc or VMAT machines. The dose absorbed to water was also measured in a RW3 solid water phantom. This phantom is suitable for quality assurance purposes since less than 2% average difference with respect to the water phantom measurements was found. In addition, output factors were assessed for different field sizes. CONCLUSIONS: A dosimetry protocol adequate for the specific features of the SSRT technique has been developed. This protocol allows measuring the absolute dose absorbed to water with an accuracy of 2%. It is therefore satisfactory for patient treatment.

Does candidate for plate fixation selection improve the functional outcome after midshaft clavicle fracture? A systematic review of 1348 patients.

INTRODUCTION: The hypothesis of this study was that patient selection for midshaft clavicle fracture (open reduction internal fixation with plate versus conservative) would give better functional outcome than random treatment allocation. METHODS: We performed a systematic literature search for primary studies providing functional score and non-union rate after conservative or surgical management of midshaft clavicle fractures. Six randomized controlled trial and 19 non-randomized controlled trial studies encompassing a total of 1348 patients were included. RESULTS: Patients treated with surgical management were found to have statistically superior Constant scores in non-randomized controlled trials than in randomized controlled trials (94.76 ± 6.4 versus 92.49 ± 6.2; p < 0.0001). For conservative treatment, randomized controlled trials were found to have significantly better functional outcome. The prevalence of non-union (6.1%) did not show significant statistical difference between non-randomized controlled trial and randomized controlled trial studies. The functional outcome after surgical management was significantly higher than after conservative management in both randomized controlled trial and non-randomized controlled trial groups. The non-union rate after surgery (1.1% for both non-randomized controlled trial and randomized controlled trial) was significantly lower than following conservative treatment (9.9% non-randomized controlled trial versus 15.1% randomized controlled trial). DISCUSSION: This review shows that patient selection for surgery may influence functional outcome after midshaft clavicle fracture. Our results also confirm that plate fixation provides better functional outcome and lower non-union rate.

Monochromatic minibeam radiotherapy: theoretical and experimental dosimetry for preclinical treatment plans.

Monochromatic x-ray minibeam radiotherapy is a new radiosurgery approach based on arrays of submillimetric interlaced planar x-ray beams. The aim of this study was to characterize the dose distributions obtained with this new modality when being used for preclinical trials. Monte Carlo simulations were performed in water phantoms. Percentage depth-dose curves and dose profiles were computed for single incidences and interleaved incidences of 80 keV planar x-ray minibeam (0.6 × 5 mm) arrays. Peak to valley dose ratios were also computed at various depths for an increasing number of minibeams. 3D experimental polymer gel (nPAG) dosimetry measurements were performed using MRI devices designed for small animal imaging. These very high spatial resolution (50 µm) dose maps were compared to the simulations. Preclinical minibeams dose distributions were fully characterized. Experimental dosimetry correlated well with Monte Carlo calculations (Student t-tests: p > 0.1). F98 tumor-bearing rats were also irradiated with interleaved minibeams (80 keV, prescribed dose: 25 Gy). This associated preclinical trial serves as a proof of principle of the technique. The mean survival time of irradiated glioma-bearing rats increased significantly, when compared to the untreated animals (59.6 ± 2.8 days versus 28.25 ± 0.75 days, p < 0.001).

[Synchroton radiotherapy]. / Radiothérapie par rayonnement synchrotron.

Radiation therapy is commonly used in the treatment of cancer. The normal tissue tolerance can be a limit to deliver enough dose to the tumor to be curative. The synchrotron beam presents some interesting physical properties, which could decrease this limitation. Synchrotron beam is a medium energy X-ray nearly parallel beam with high intensity. Three methods are under preclinical investigations: the microbeam, the minibeam and the stereotactic radiotherapy. The first two use a geometric irradiation effect called spatial fractioning. The last one use highly conformational irradiation geometry combined with a dose enhancement due to the presence of high-Z element in the target. Synchrotron radiotherapy preclinical experiments have shown some curative effect on rodent glioma models. Following these encouraging results a phase I/II clinical trial of iodinated enhanced stereotactic synchrotron radiotherapy is currently being prepared at the European Synchrotron Radiation Facility.