Aim

The aim of this work was to evaluate, via foot and ankle TC scans, the outcomes of the use of a bone substitute (CERAMENT|™G) and the growth of native bone in the treatment of osteomyelitis (OM) of the diabetic foot.

Prosthetic joint infections (PJI) occur infrequently, but they represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative S. epidermidis are the most commonly infecting agents associated with PJI. Nowadays, Gram-negative species like Escherichia coli and Pseudomonas aeruginosa are gaining relevance.

The use of TiO2 conical nanotubular doped with fluorine and phosphorous (FP-cNT) surfaces is an interesting approach to prevent surface bacterial colonization during surgery and favouring the osseointegration. Despite of there are serum markers related with PJI, to date there is described no biomaterial-related marker that allows detecting PJI. Here we describe the adherence and the bactericidal effect of FP-cNT and its capacity of marking the non-fermenting bacteria that have been in contact with it by Al. This metal is delivered by FP-cNT in non-toxic concentrations (between 25 and 29 ng/mL).

F-P-cNT layers on Ti6Al4V alloy were produced as described previously by our group. Ti6Al4V chemical polishing (CP) samples without nanostructure were used as control and produced as described previously.

S. aureus 15981, S. epidermidis ATCC 35984, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 strains adherence study was performed using the protocol described by Kinnari et al. in 0.9% NaCl sterile saline with a 120 min incubation. After incubation, the samples were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Proportion of live and dead bacteria was calculated and studied by using ImageJ software. The experiments were performed in triplicate. The aluminum concentration was estimated in the supernatant after incubation and in the 0.22 µm filtered supernatant by atomic absorption in graphite furnace.

The statistical data were analyzed by nonparametric Kruskal-Walis test and by pairwise comparisons using the nonparametric unilateral Wilcoxon test with a level of statistical significance of p<0.05. The values are cited as medians.

Our results show that the bacterial adherence of all tested species significantly decreased on FP-cNT compared to CP except P. aeruginosa ATCC 27853: 19.8% for S. aureus 15981, 45.3% for S. epidermidis ATCC 35984 and 8.1% for E. coli ATCC 25922. The bacterial viability decreased 2-fold for S. aureus 15981, and 5-fold for S. epidemidis ATCC 35984, but increased 95% for P. aeruginosa ATCC 27853 and there no was variation for E. coli ATCC 25922 on FP-cNT compared to CP. Only supernatant P. aeruginosa ATCC 27853 shows significant Al detection after 120 min incubation (p<0.05).

In summary, F-P cNT is a promising biomaterial that besides favoring osseointegration and potential usefulness as drug carrier, present bactericidal, non-stick ability (at least for staphylococci and E. coli) and is able to mark P. aeruginosa with Al, which could be potentially monitored in serum and urine in patients with PJI.

Aim

Since July 2013 our group has been using an antibiotic bone substitute, composed of calcium sulphate, hydroxyapatite and gentamicin sulphate (CSH + HA + GS), in the treatment of osteomyelitis (OM) in diabetic foot. The aim of this work was to evaluate the mid-term efficacy of this treatment regime on outcomes. A favourable outcome in diabetic foot includes no recurrence of OM, healed soft tissues and the ability to weight-bear.

Aim of this work was to evaluate the efficacy of a new antibiotic bone substitute (CERAMENTTM|G) in the treatment of osteomyelitis (OM) in diabetic foot.

From June 2013 to April 2015 we used a new Calcium Sulphate Hemihydrate + Hydroxyapatite + Gentamicin Sulfate (CSH + HA + GS) compound to fill resected bone voids following surgical intervention in cases of diabetic foot OM. The uniqueness of this product is that it induces native bone growth, while the synthetic bone disappears and antibiotic is released into the surrounding tissues, maintaining high gentamicin concentrations for some weeks.

In 20 patients, with or without Charcot neuroarthropathy and post-lesional osteomyelitis, after removal of infected bone we applied 10 to 20 ml CSH + HA + GS, filling the residual spaces and aiming to stabilize the remaining bone fragments. When needed, these arthrodeses were stabilized by external-internal hybrid fixators. X-ray evaluations and, when indicated, MRI evaluations were performed before and after surgical intervention, and 3 months post-op. Revascularization with percutaneous angioplasty was performed when needed.

20 patients affected by OM were treated, 4 of them having 1st metatarsal head involvement, 4 having heel involvement, 12 tarsal and hindfoot involvement. After surgical intervention all of them were treated with standard medication and pressure relief.

The three 1st metatarsal OM cases healed, both in regards to infection and lesions. One of the patients is still ongoing. One of the patients with heel OM presented with a worsening of the infection and was treated by major amputation, another one presented with good soft tissue growth and, two months from the intervention, and in the absence of clinical signs of OM relapse, was treated with a sural fasciocutaneous pedicled flap; of the remaining two patients one heald and the other is still ongoing; 11 of the 12 patients who had midfoot or hindfoot partial resections healed, one patient is still ongoing. The healed patients are all wearing suitable shoes.

The use of a new CSH + HA + GS bone substitute has shown to be efficacious in inducing OM healing and preserving foot structures in diabetic feet.

Introduction: The correct position of the knee arthroplasty components is associated with a better result of the prosthesis.

In the tibial component, both intramedullar and extramedullar instrumentations have been used for its fiability, but in the femoral component intramedullar guides are more precise than extramedullar ones.

The use of the intramedullar guide for the femoral component is not always possible, because a significant deformity of the femoral shaft or when a intramedullar device has been implanted in the femur.

We have studied the alineation of the components of computer assisted total knee arthroplasties in a group of patients with femoral deformities or implants.

Material and methods: We have used the surgical navigator Stryker-Howmedica for the implantation of a knee arthroplasty in a group of 10 patients in which a endomedullar femoral guide can not be used for femoral shaft severe deformities (6 cases): Paget disease (1 case), previous femoral osteomyelitis (2 cases) or previous femoral fractures (3 cases), or a shaft device was in the femoral shaft (4 cases): long hip femoral stem (3 cases) or a femoral nail (1 case) .

We have studied the alineation of femoral and tibial components with a whole-leg X-ray and Computer Tomography.

Results: All the femoral and tibial components have been implanted in a good position (90 +/– 2 degrees in the A-P plane and a femorotibial axe 180 +/– 3 degrees. The alineation in the sagital and axial planes have been inside the desired values in all cases also.

Discussion: It is generally accepted than intramedullary guides for the femoral component is the gold standard in arthroplasty of the knee.

In the last years, the development of computer assisted systems has allowed to obtain femoral and tibial cuts referred to the mechanical axes of the bone, without using mechanical guides for the alineation.

In some studies these navigation systems are better than mechanical instruments in terms of alineation of the components in cases without great deformities.

In this study, with some cases with severe femoral shaft deformities or with some intramedullary devices that does not allow the use of intramedullary femoral guides, we think that the indication to use a surgical navigator should be nearly absolute.