The use of antibiotic-impregnated cement in infected reconstructions after resection for bone tumours

Combined Orthoplastic Approach in Fracture-Related Infections of the Distal Tibia

This series reports on the treatment of distal tibia (DT) fracture-related infections (FRI) with a combined orthoplastic approach. Thirteen patients were included. In eight patients with extensive bone involvement and in those with a non-healed fracture, the DT was resected (“staged approach”). In five cases, the DT was preserved (“single-stage approach”). A wide debridement was performed, and the cavity was filled with antibiotic-loaded PerOssal beads. All patients had a soft-tissue defect covered by a free vascularized flap (anterolateral thigh perforator flap in eight cases, latissimus dorsi flap in five). At the final follow-up (mean 25 months, range, 13–37), no infection recurrence was observed. In one patient, the persistence of infection was observed, and the patient underwent a repeated debridement. In two cases, a voluminous hematoma was observed. However, none of these complications impacted the final outcome. The successful treatment of FRI depends on proper debridement and obliteration of dead spaces with a flap. Therefore, when dealing with DT FRI, debridement of infected bone and soft tissues must be as radical as required, with no fear of the need for massive reconstructions.

Is sonication of antibiotic-loaded cement spacers useful in two-stage revision of prosthetic joint infection?

BACKGROUND

In a two-stage exchange protocol for prosthetic joint infection (PJI), bacteria surviving over the antibiotic-loaded cement spacers may cause the persistence of infection with renewed clinical symptoms following the surgery. Culture after sonication of removed prosthesis is more sensitive than conventional periprosthetic tissue culture for the microbiological diagnosis of PJI. The aim of this study was to assess whether sonication of the spacer at the time of the second-stage procedure may improve the diagnosis of persistent PJI.

METHODS

We evaluated by microbiological culture the sonication fluid from 222 cement spacers implanted in a two-stage exchange protocol in 157 patients affected by PJI. A mean of 1.3 (range, 1-4) spacer per patient was performed.

RESULTS

In 53 out of 222 spacers analyzed infection was confirmed according to the MSIS criteria. In 22 cases the infection was confirmed by both cultures on periprosthetic tissue and on sonication fluid from the spacers. In 23 cases persistent PJI was identified because of only cultures of periprosthetic tissue and 8 because of results obtained after spacer sonication. The sensitivity of periprosthetic tissue cultures was higher than that of cultures performed on sonication fluid (84.9% vs 56.6%, p < .001).

CONCLUSIONS

Even though sonication of cement spacers has performances inferior than those reported for prosthesis, it can be considered a complementary method to unravel persistent infection during a two-stage exchange protocol for PJI.

Lower limb reconstruction in tumor patients using modular silver-coated megaprostheses with regard to perimegaprosthetic joint infection: a case series, including 100 patients and review of the literature

PURPOSE AND OBJECTIVE

Bone resection regarding adequate surgical margins is the treatment of choice for malignant bone tumors. In the case of metastasis-related complications, so-called skeletal-related events, it is highly important to achieve pain relief and a stable joint situation to re-mobilize the patients immediately following surgery. To bridge the often large osseous defect zones after tumor resection, both cemented and uncemented modular endoprosthetic systems are widely used. Patients undergoing tumor-related endoprosthetic orthopedic surgery are facing high risk for developing a periprosthetic joint infection (PJI). The immunocompromised condition due to anti-neoplastic treatment and long operation time with large exposure of tissue contributes to a high risk of infection.

METHODS

The authors present a case series of 100 patients (31% primary bone tumor and 69% metastasis-related surgery) undergoing tumor-related lower limb salvage surgery with special regard to periprosthetic joint infection and the management of this "difficult to treat" situation. Furthermore, a review of the current literature regarding infection following bone tumor resection and endoprosthetic reconstruction is performed and discussed.

RESULTS

The median follow-up was 24 months (range 12-108 months). Ten patients (10%) suffered from a periprosthetic joint infection. We recorded six acute infections (type I) <4 weeks after surgery, one infection >4 weeks after surgery (type II), and three late infections (type III). According to the definition of Laffer et al., three of our patients (30%) are probably free of infection, one patient died of PJI-associated sepsis, and five patients were free of infection, but without restoration of the affected joint.

CONCLUSION

In conclusion, our own results show that perimegaprosthetic joint infection among silver-coated implants, in patients undergoing tumor-related surgery of the lower limb, is lower compared to non-silver-coated implants. Due to heterogeneity of patients and potential treatment options, the treatment regime should be tailored for the patients' individual situation.

The pedicle screw-rod system is an acceptable method of reconstructive surgery after resection of sacroiliac joint tumours

Hemipelvic resections for primary bone tumours require reconstruction to restore weight bearing along anatomic axes. However, reconstruction of the pelvic arch remains a major surgical challenge because of the high rate of associated complications. We used the pedicle screw-rod system to reconstruct the pelvis, and the purpose of this investigation was to assess the oncology, functional outcome and complication rate following this procedure. The purpose of this study was to investigate the operative indications and technique of the pedicle screw-rod system in reconstruction of the stability of the sacroiliac joint after resection of sacroiliac joint tumours. The average MSTS (Musculoskeletal Tumour Society) score was 26.5 at either three months after surgery or at the latest follow-up. Seven patients had surgery-related complications, including wound dehiscence in one, infection in two, local necrosis in four (including infection in two), sciatic nerve palsy in one and pubic symphysis subluxation in one. There was no screw loosening or deep vein thrombosis occurring in this series. Using a pedicle screw-rod after resection of a sacroiliac joint tumour is an acceptable method of pelvic reconstruction because of its reduced risk of complications and satisfactory functional outcome, as well as its feasibility of reconstruction for type IV pelvis tumour resection without elaborate preoperative customisation.

Level of evidence: Level IV, therapeutic study.

Evaluation and treatment of extremity metastatic disease

Metastases can occur as part of the natural progression of a variety of malignancies and their mode of spread, manner of presentation, and prognosis are as variable as their primary sources. The ultimate goal of musculoskeletal treatment of skeletal metastases is to get the patient in question back to his or her previous level of function as soon as possible. Skeletal metastases are seldom life threatening and their treatment will rarely render someone cured of their primary disease. Nevertheless, involvement of a musculoskeletal specialist as a part of the multidisciplinary approach can and very often does provide significant improvement in patients' qualities of life. The purpose of this chapter is to discuss the evaluation of a patient with suspected metastatic disease involving the musculoskeletal system and their pre-, intra-, and post surgical management as part of a multidisciplinary team.

Treatment solutions are unclear for perimegaprosthetic infections

BACKGROUND

Infection about a megaprosthesis is a dreaded complication. Treatment options vary from débridement alone to staged revisions, arthrodesis, and amputation. Indications for how to treat this complication are unclear.

QUESTIONS/PURPOSES

We therefore determined (1) the incidence of perimegaprosthetic infections, (2) the methods of treatment, (3) the number of patients who failed their original treatment plan, and (4) the characteristics of the infection.

METHODS

We retrospectively identified 291 patients who had megaprostheses implanted between 2001 and 2011 and identified all those surgically treated for a perimegaprosthetic infection during that time. We defined a treatment failure as any unplanned reoperation or death due to uncontrolled infection. All patients with failure had a minimum followup of 1 year (mean, 3.3 years; range, 1-8 years).

RESULTS

Of the 291 patients, 31 (11%) had subsequent infections. Surgical management varied among irrigation and débridement (n=15), single-stage revisions (n=11), two-stage revisions (n=4), and amputations (n=1). Sixteen patients failed their original treatment plan: 13 required additional surgery and three died. Infections were mostly chronic and single organism with five being methicillin-resistant Staphylococcus aureus.

CONCLUSIONS

An 11% incidence of perimegaprosthetic infections is consistent with the increased risk of infection seen in other studies. A variety of surgical methods were employed at our institution and by those contributing to the literature without clear evidence of superiority of one method over another. Given the complicated medical and surgical histories of these patients, individualization in decision making is necessary.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Primary cement spacers: a cost-effective, durable limb salvage option for knee tumors

Of a total of 818 limb sparing resections in the lower limb requiring reconstruction between December 2002 and April 2010 at our centre, primary cement spacers were used in 15 cases. In three cases they were used as joint sparing intercalary reconstructions and in 12 cases knee arthrodesis was done. Implants used to provide stability to the construct included stacked intramedullary Kuntscher nails in four, an interlocking nail in one, plates in two and a combination of nail with plate in eight. Mean length of bone resected was 18 cm. Mean follow-up was 26 months (10-87 months). There were no local recurrences and none of the spacers needed revision for mechanical failure. The Musculoskeletal Tumor Society score for patients ranged from 20 to 29 with a mean of 24 (80%). Patients with intercalary resection had better functional scores than those with arthrodesis. The construct was successfully revised to a vascularised fibula arthrodesis or prosthesis with good eventual function in three cases. Cement spacers are a suitable cost-effective, durable reconstruction modality in selected patients with good functional outcomes. They are an option to amputation in patients with financial constraints and those that present with large volume or infected fungating tumors.

Primary arthrodesis and sural artery flap coverage for subtalar joint osteomyelitis in a diabetic patient

Diabetic chronic wounds with joint sepsis and osteomyelitis of the hindfoot can be difficult pathologic entities to treat. Limb salvage approaches are based on careful preoperative evaluation, surgical technique, and postoperative care. This article reviews the overall management of subtalar joint osteomyelitis with a case report showing primary arthrodesis with external fixation and soft tissue coverage with a reverse sural artery neurofasciocutaneous flap.

Management of septic complications following modular endoprosthetic reconstruction of the proximal femur

In a retrospective single-centre study 170 consecutive patients were included who received a Kotz modular prosthesis after resection of bone tumours of the proximal femur to evaluate the management of prosthetic infection. Infection occurred in 12 of 166 patients available for follow-up (six males; six females; mean age, 47 years; range, ten to 75 years) after a mean of 39 months (range, one to 166 months; infection rate, 7.2%). Mean follow-up was 54 months (range, four to 200 months). One patient died of septic shock. Two patients were treated by wound revision only. Treatment of infection in the remaining patients was one-stage revision in eight and hip disarticulation in one. Infection control by one-stage revision was achieved in five of eight patients; re-infection occurred in three patients and was successfully treated by further revision in all of them. The overall success rate for controlling infection was 83.3%.

Inhibition of Staphylococcus epidermidis biofilms using polymerizable vancomycin derivatives

BACKGROUND

Biofilm formation on indwelling medical devices is a ubiquitous problem causing considerable patient morbidity and mortality. In orthopaedic surgery, this problem is exacerbated by the large number and variety of material types that are implanted. Metallic hardware in conjunction with polymethylmethacrylate (PMMA) bone cement is commonly used.

QUESTIONS/PURPOSES

We asked whether polymerizable derivatives of vancomycin might be useful to (1) surface modify Ti-6Al-4V alloy and to surface/bulk modify PMMA bone cement to prevent Staphylococcus epidermidis biofilm formation and (2) whether the process altered the compressive modulus, yield strength, resilience, and/or fracture strength of cement copolymers.

METHODS

A Ti-6Al-4V alloy was silanized with methacryloxypropyltrimethoxysilane in preparation for subsequent polymer attachment. Surfaces were then coated with polymers formed from PEG(375)-acrylate or a vancomycin-PEG(3400)-PEG(375)-acrylate copolymer. PMMA was loaded with various species, including vancomycin and several polymerizable vancomycin derivatives. To assess antibiofilm properties of these materials, initial bacterial adherence to coated Ti-6Al-4V was determined by scanning electron microscopy (SEM). Biofilm dry mass was determined on PMMA coupons; the compressive mechanical properties were also determined.

RESULTS

SEM showed the vancomycin-PEG(3400)-acrylate-type surface reduced adherent bacteria numbers by approximately fourfold when compared with PEG(375)-acrylate alone. Vancomycin-loading reduced all mechanical properties tested; in contrast, loading a vancomycin-acrylamide derivative restored these deficits but demonstrated no antibiofilm properties. A polymerizable, PEGylated vancomycin derivative reduced biofilm attachment but resulted in inferior cement mechanical properties.

CLINICAL RELEVANCE

The approaches presented here may offer new strategies for developing biofilm-resistant orthopaedic materials. Specifically, polymerizable derivatives of traditional antibiotics may allow for direct polymerization into existing materials such as PMMA bone cement while minimizing mechanical property compromise. Questions remain regarding ideal monomer structure(s) that confer biologic and mechanical benefits.

Use of antibiotic cement-impregnated intramedullary nail in treatment of infected non-union of long bones

BACKGROUND

In cases with infected non-union, the primary step is eradication of the infection before attempting to achieve union. Release of antibiotics from the bone cement at a high concentration and its penetration to the surrounding tissues, including cortical and cancellous bone, prompted the use of antibiotic cement in the control of bone infection. The aim of this study is to summarize our experience with the use of antibiotic cement-impregnated intramedullary nail (ACIIN) for control of infection in cases of infected non-union with bone defect.

MATERIALS AND METHODS

We prospectively studied 25 cases of infected non-union (23 femora and two tibiae). There were 24 males and one female, with the mean age being 33 years (range, 21-58 years). All patients had high-velocity road traffic accidents except one patient who had farmland injury. There were seven closed fractures, one grade I compound, two grade II compound fractures, five grade IIIA compound fractures, and 10 grade IIIB compound fractures. ACIIN was used in all cases after adequate debridement. Patients were classified according to the amount of bone defect present after debridement: group 1 with bone defect <4 cm (n=13), group 2 with bone defect >/=4-<6 cm (n=7), and group 3 with bone defect >/=6 cm (n=5). Infection control was judged on the basis of discharge through the wound and laboratory parameters. All patients were followed-up, with an average follow-up time of 29 months (range, 18-40 months). The mean duration of retention of the intramedullary rod was 8 weeks (range, 6-12 weeks).

RESULTS

In group 1, all cases achieved infection control, with three patients achieving bone union without any need of secondary procedure. In group 2, all cases achieved infection control but the time taken was significantly longer than for group 1 (P value 0.0002). All the cases required a secondary procedure in the form of either interlocking intramedullary nailing with iliac crest bone graft or Ilizarov ring fixator application to achieve union. None of the cases in group 3 achieved infection control.

CONCLUSION

ACIINs are useful for infection control in cases of infected non-union with bone defect <6 cm. In cases with defect >6 cm, other alternatives should be used.

Treatment of experimental osteomyelitis by methicillin resistant Staphylococcus aureus with bone cement system releasing grepafloxacin

The authors examined the effectiveness of the local anti-microbial treatment on methicillin resistant Staphylococcus aureus (MRSA) experimental osteomyelitis. Thirty-six rabbits with chronic MRSA osteomyelitis of the right femur were treated with local grepafloxacin delivery system prepared by a mixture of acrylic bone cement (polymethyl methacrylate, PMMA) plus 4% grepafloxacin. Osteomyelitis was induced by inoculating MRSA (100 microl of cultured bacteria; 10(7)) and the local insertion of a needle, serving as a foreign body, at the upper third of the femur. The course of the infection was followed by clinical, radiographic and microbiological examination. In the third week, all animals were re-operated, needles were removed, and antibiotic containing acrylic cement was implanted. Thereafter, one control and five treated animals were sacrificed per week, within 6 weeks. Osteomyelitis was found in all rabbits. In vitro grepafloxacin levels remained high throughout the 6 weeks of the experiment. Histologically tissue reaction against the cement was not observed. Osteomyelitis lesions and bone structure were progressively repaired after cement implantation. Biomechanical analysis showed no significant influence on the mechanical properties of acrylic cement due to grepafloxacin. The above mixture could prove to be an important supplementary method for the treatment of bone infections. Such a system could replace the use of gentamycin PMMA beads in the treatment of patients with chronic osteomyelitis due to MRSA. Furthermore, the proposed method could be used as a spacer after removal septic loosened prostheses in combination with systemic administration of antibiotics.

Risk of amputation following limb salvage surgery with endoprosthetic replacement, in a consecutive series of 1261 patients

Endoprosthetic replacements are commonly used for limb salvage following surgical excision of bone tumours. Advantages include initial reliability, rapid restoration of function and their ready availability. Potential long-term problems include loosening, infection and mechanical failure. Increasing problems may lead to the necessity for amputation; this paper assesses that risk. A total of 1,261 patients have undergone endoprosthetic replacements in our centre in the past 34 years, with a total of 6,507 patient years of follow up. A total of 112 patients have had subsequent amputation. The reasons for amputation were local recurrence in 71, infection in 38, mechanical failure in two and chronic pain in one. The proximal tibia had the greatest risk of amputation (n=38/245). The time to amputation varied from 2 days to 16 years, with a mean of 31 months. The risk of amputation decreased with time, although 10% took place after more than 5 years.

Successful reimplantation of total femoral prosthesis after deep infection

A 16-year-old boy developed a deep infection with methicillin-resistant Staphylococcus aureus 6 months after total femoral replacement including knee and hip joints. The deep infection was eradicated by the use of débridement with continuous irrigation and removal of all prosthetic components followed by insertion of an antibiotic-impregnated cement spacer. Six weeks later, the total femoral prosthesis could be successfully reimplanted with both acetabular and tibial components. Two and half years later, the patient remained free of infection. Débridement with continuous irrigation and an antibiotic-impregnated cement spacer can be a feasible technique for the treatment of deep infection after large prosthetic replacement. Furthermore, reimplantation should be performed after a short waiting period. Such treatment should be considered before deciding on amputation.

Use of antibiotic-impregnated cement in total joint arthroplasty

The use of antibiotic-impregnated cement in revision of total hip arthroplasty procedures is widespread, and a substantial body of evidence demonstrates its efficacy in infection prevention and treatment. However, it is not clear that it is necessary or desirable as a routine means of prophylaxis in primary total joint arthroplasty. In the management of infected implant sites, antibiotic-impregnated cement used in one-stage exchange arthroplasties has lowered reinfection rates. In two-stage procedures, use of beads and either articulating or nonarticulating antibiotic-impregnated cement spacers also has lowered reinfection rates. In addition, spacers reduce "dead space," help stabilize the limb, and facilitate reimplantation. Problems associated with antibiotic-impregnated cement in total joint arthroplasty include weakening of the cement and the generation of antibiotic-resistant bacteria in infected implant sites.

Arthodesis of the infected ankle and subtalar joint

Arthrodesis of the ankle or subtalar joint for limb salvage in joint sepsis is extremely complicated, and produces a protracted course of management. A successful outcome is founded on the diligence of the surgeon in the preoperative evaluation, intraoperative technique, and postoperative care of the patient. Liberal consultation with infectious disease specialists, vascular, and plastic surgeons is recommended. Recognition of patient-specific comorbidities is essential to the selection of appropriate limb salvage candidates.