SAFE DualCore Universal Nail. Interlocking Nail with a long lasting PMMA cement withantibiotic releasing core.Craveiro Lopes N, Escalda C and Leão MOrthopedic Department, Garcia de Orta HospitalAlmada, PortugalWe have conducted a experimental and clinical pilot study on a modified Grosse nail withtransfixing holes along both sides and filled with PMMA cement with antibiotics, with the intensionof develop a fixation device adapted to be used in cases of bone fracture or fragility with high risk ofinfection. This pilot nail proved to be 10% more resistant than the original Grosse nail and releasesantibiotics in 6 to 12 folds the MIC during more than 12 months, characteristics suitable butinsufficient for some of the cases with late consolidation, very common in our practice...

So we constructed a stronger nail and developed a new technology, named DualCore, to get moreresistance to fatigue and opened more releasing holes that can be used to fix intermediary fragments,using two antibiotics in higher concentration, to permit a better local elution. We call this newdevice, SAFE DualCore Universal Nail.

This new nail was tested in laboratory. Without the double core, this new nail shows 100% moreresistance than the Grosse nail and with the DualCore Technology, it is 220% more resistant than thestandard Grosse nail.

With regard to the antibiotic elution values, we can see with the brown line the pattern of releasefrom a cylinder of cement and of the modified Grosse nail (red line), both with one gram ofvancomicin, with an average level of release of 8 micrograms per milliliter ... While the new nailwith more releasing holes and 2 grams of vancomicin releases an average concentration of

antibiotics of more than 14 micrograms per milliliter.

So, the advantages of this new biologically active nail include a better resistance, more than thetriple of the standard Grosse nail, adapted to cases of late consolidation ... And a local antibioticelution in concentrations 14 folds the minimum inhibitory concentration during the time ofimplantation of the nail, allowing an effective suppressive therapy.The preparation of the SAFE nail is a 10 minute procedure and includes the wrapping of the nailwith a Esmach band and the injection of a misture of apropriate antibiotics inside the nail using acement gun.

From June 2011 to July 2012, we used this nail in 11 cases, including one case of open fractures, oneconversion from external fixation on a open fracture, four cases of lengthening with external fixationthen nailling, two cases of knee artrodesis with external fixation then nailling, one case of ankleartrodesis with nail, one case of osteomyelities after nailling and a case of fracture in cronicosteomyelitic bone.Bacteriological examination was made of exudate in 9 of eleven cases praior to the nailling,revealing clinically aggressive bacteria in 9 cases, predominantly the methicillin sensitiveStaphylococcus wich appeared in 65% of patients.Clinical casesThis patient had a grade II open fracture and was nailled immediately. We can observe the perfect fitof the nail to the shape of the tibia in the profile.

The patient at six weeks of follow up begun to do total weight bearing and returned to work as akarate teacher.

This second patient had a sequelae of an infected total knee replacement. After 10 operations, weproceeded to a knee arthrodesis and tibial lengthening with a Ilizarov apparatus. Three months afterwe have done a conversion to a SAFE DualCore Universal extra-long nail, reinforced only in thearea of the knee and tibial lengthening, leaving some flexibility in the proximal femur.

This was an achondroplasic patient that was subjected to a lengthening with a monolateral distractorover a kirshnner rod and the result at 3 months of follow up after the conversion to a SAFEDualCore nail, with consolidation, without infection.This 21 years old patient with a sequela of high riding Congenital Dislocation of the Hip subjected

to a hip reconstruction with Ilizarov, frame was infected with a Staphilococus. We have done aconversion to a SAFE nail and two months after the patient had a fall and broke the femur above thenail.

We exchange the SAFE nail with a longer one. At two months of follow up there are no infectionpresent and consolidation is on the way.This forty three years old female had a 4 cm femoral shortening after a fracture and was subjectet toa lengthening with a Ilizarov frame. After the distraction period at the end of two months she wasinfected with a Staphilococus Aureus.

We then made a conversion to a SAFE DualCore nail. Thee result at the end of two and a halfmonths with consolidation without infection.

A twenty four years old man was run over by a car with open fractures of both legs, was operatedwith standard interlocking nails. One month after a fistulae apeared on the right leg and bacteriologyrevealed a Enterobacter Cloacae infection. We removed the nail, cleaned the medulary canal with theRIA system and introduced a SAFE DualCore Universal Nail with Meropenem and Vancomicin,antibiotics guided by the sensibility tests. The control at one month after surgery with cure of theinfection and patient doing full weight bearing.Finally this thirty two years old man presenting an ankle arthrosis after a open fracture with infectionwhen he was 17 years old, with a equinus and suppinatus foot…

He was subjected to an ankle arthrodesis with a SAFE DualCore Universal nail. The control at 2moths of follow up with consolidation in a good position.According to the classification of Paley, in all the treated cases, we had 2 obstacles, including afracture above the nail solved by a longer nail and a malrotation solved by correction with exchangeof distal screws.We had no complications, namelly infections or nail failure.The conclusions of this preliminary report are very encouraging. We found the procedure simple andfast to perform, the nail is more resistant than the original one, more than three times, It is possible tointerlock intermediary fragments, there are a possibility to chose the right antibiotic and with 2grams of antibiotics, the release is more than 14 folds the MIC throughout the time of implantationof the nail, we found that the reaming procedure and the stability of the nail leads to a fasterconsolidation. The preliminary clinical results are excellent, with no infection, with less time ofhospitalization and treatment costs.