Aims

Infections of bone usually require multiple surgery and prolonged periods of treatment. One reason for problems is found in the presence of stationary phase bacteria embedded in biofilms that show increased resistance against conventional antibiotic therapy (up to 1000x MIC). Biofilms adhere to surfaces of avital material making radical debridement a prerequisite for cure. Osseous defects are common in such conditions and need to be addressed. To avoid re-infection high local antbiotic concentrations are necessary. Allograft bone may be impregnated with high loads of antibiotics using a special incubation technique. The resulting antibiotic bone compound (ABC) provides high and long lasting concentrations at the site of infection and is likely to restore bone stock simultaneously. Based on this technology we have developed a new surgical technique.

Infection of total hip replacement (THR) is a serious complication, usually necessitating complete removal of implants and thorough debridement of the site. Mostly implant removal is followed by several weeks of antibiotic therapy before a new prosthesis is inserted. One stage exchange using antibiotic containing cement did not gain widespread use because of several risks, although the possible clinical and economic advantages are evident. Uncemented revision techniques seem to provide better long term results, however in septic cases its use so far has been restricted to two stage procedures. Allograft bone impregnated with high loads of antibiotics using a special technique (antibiotic bone compound ABC) is likely to create markedly higher concentrations of antibiotics in its surrounding than cement.

Between 1998 and 2004 37 patients with infected THR were treated using a standardized protocol. Patients were 17 male and 20 female, their age at revision was 42–83 yrs with a mean of 68,5yrs. After removal of the implants a radical debridement and intensive pulsed lavage was performed. Bone deficiencies were filled with cancellous bone, impregnated with high loads of Vancomycin or (in cases with gramnegative cultures) a combination with Tobramycin (ABC). After impaction uncemented implants were anchored following the principles of press-fit fixation, all without cement; usually we preferred a rectangular diameter titanium stem and a hemispherical cup. Additional ABC was placed around eventually uncovered parts of the implants and impacted for good stability. Wounds were drained and closed immediately; rehabilitation was performed as after non-septic surgery. Cultures taken intraoperatively revealed growth of coag.neg.staph (19x), s.aureus (11x), MRSA (5x), enterococci (8x) and other grampositive pathogens (6x), respectively. In 8 hips gramnegative germs were found additionally. Patients were evaluated prospectively 2 weeks, 6 weeks, 3 months, 6 months and one year after surgery. After the first year evaluation was retrospective. Follow up included clinical and radiological examination and laboratory data (CRP, ESR, blood count, urea and creatinine).

Three hips required re-revision because of re-infection, the remaining 34 hips (92%) stayed infect free and stable throughout a follow up period between 2 and 8 years (mean 4,4yrs). No adverse side effects could be found. Incorporation of grafted bone followed the same patterns as known from unimpregnated grafts.

Infected THRs may be exchanged within a single procedure using antibiotic impregnated allograft bone, providing biological reconstruction of bone stock, stable insertion of an uncemented implant and control of infection. Since only one intervention is necessary rehabilitation of patients is improved and costs are markedly reduced. Improved long term results may be expected.

Infection of total knee replacement (TKR) is considered a devastating complication, which necessitates complete removal and thorough debridement of the site. Usually long term antibiotic treatment and a multitude of surgical interventions within a period of several months are required until a definitive supply can be achieved. Osseous defects are common in such conditions and need to be addressed during re-implantation. Managing removal, debridement, reconstruction and re-implantation within a single operation is the ideal solution, both for the patient and the treating team, but rarely executed due to the fear of re-infection. Allograft bone may be impregnated with high loads of antibiotics using a special incubation technique. The resulting antibiotic bone compound (ABC) provides high and long lasting antibiotic levels at the site of infection and is likely to restore bone stock. We have investigated the results of one-stage exchange of infected TKR using ABC together with uncemented implants.

Between 1998 and 2004 nineteen exchange procedures of infected TKRs were performed in a single stage, all of them without the use of bone cement. After removal of the implants and radical debridement bone voids were filled with ABC using a modified impaction technique. Consequently, new uncemented implants were inserted. We mainly used the revision type of the LCS knee (DePuy, J& J) as long as ligamentary stability was considered sufficient. Otherwise, we used a custom-made uncemented version of the LINK Rotational Endo Model. Joints were drained and closed immediately; rehabilitation did not differ from uninfected revision.

One knee required re-revision because of persisting infection. The remaining 18 patients stayed infect-free for a period between 2 and 8 years after surgery. In two knees loosening was found after one year, once of the tibial and once of the femoral component. Both were found infect-free at the time of re-revision. All could be successfully revised using the same technique again. No adverse side effects could be found. Incorporation appeared as after grafting with unimpregnated bone grafts.

Using antibiotic-impregnated allografts eradication of pathogens, grafting of defects and re-insertion of an uncemented prosthesis may be accomplished in a one-stage procedure. Since the graft gradually is replaced by healthy own bone, improved long-term results may be expected as well as improved conditions in the case of another revision.

Several orthopaedic operations are encumbered with a high risk of infection. Early detection of such complication is of utmost importance for achieving good results.

From 1990 to 1998 a prospective study was done in 104 orthopaedic patients, who had a higher risk for postoperative infections. Diagnoses had been chronic osteomyelitis (47 cases), bone transplantation after osteomyelitis (19 cases), malignant bone tumors receiving chemotherapy (16 cases) and revision alloarthroplasty (22 cases). Consecutive levels of leucocytes in the wound drainages (deep and subcutaneus), white blood cell count (WBC) and c-reactive proteine (CRP) were analyzed.

Seventeen patients (septic group) were reoperated for suspected infection. The culture discount revealed Staphylococcus aureus (7 cases), Staphylococcus epidermidis (5 cases), Streptococcus hemoliticus (1 case), Mycobacterium tuberculosis (1 case), Enterococcus fae-calis (1 case), mixed organisms (2 cases), and histological signs of infection (4 cases). Comparing the aseptic and septic group no difference was noted for WBC < 2 days (p = 0.39), 2–3 days (p = 0.18), 3–6 days (p = 0.44) and > 6 days (p = 0.46). CRP difference was noted on the fourth day: mean 7.6 +− 0.8 mg/dl (range 6.0 to 9) (septic group); mean 5.9 +− 1.2 mg/dl (range 3.2 to 8.4) (aseptic group) (p < 0.001). The deep drainage leucocytes demonstrated to 12 hours: mean 5636 +− 2134 (range 2400 to 11200) (septic group) and mean 8531 +− 3312 (range 3100 to 18200) (aseptic group) (p < 0.001). 36 to 48 hours: the values changed adversely. 48 to 72 hours: mean 9146 +− 3666 (range 4700 to 16200) (septic group) and mean 2393 +− 879 (range 1100 to 4100) (aseptic group) (p < 0.001). The subcutaneus drainage leucoytes were 1.5 to 1.9 times higher (aseptic group) and 0.13 to 1.03 times lower (septic group) compared to the deep drainage.

We recommend deep drainage leucocytes monitoring 48 to 72 hours after the operation. Values greater 4100 (upper range of aseptic control) are suspicious and over 9146 (mean value of septic group) are strongly associated with an underlying wound infection.

For local antibiotic therapy gentamycin is in clinical use since many years, originally in the form of PMMA beads, later also in the form of resorbable collagen fleece. A prospective study comparing the efficacy of both application forms so far is missing.

In a prospective study 108 patients with chronic sclerosing osteomyelitis were treated by a standardised operative debridement protocol. The debrided cavities were filled with 54 patients (group 1) were treated by local antibiotic beads (Septopal) and 54 patients (group 2) by local resorbable antibiotic fleece (Sulmycin). Both groups were comparable concerning age, location, duration of operation, type of osteomyelitis and predisposing factors. The mean follow-up was 6.1 years (range 3.8 – 9.3). Evaluation was done for the re-operation rate, CRP and ESR, white blood cells and local wound healing criteria.

Twenty-six patients (44 per cent) underwent one or more revision operations because of persistent infection.

In group I 67 per cent and in group II 20 per cent (p = 0.0001). No difference was noted for CRP (p = 0.46), ESR (p = 0.09), white blood cells (p = 0.24) and local wound healing criteria (p =0.34).

After local gentamycin fleece application the early re-operation rate is significantly lower compared to gentamycin beads. After a treatment period of 3 month this difference disappears.

Infection of the rear foot and ankle joint often leads to destruction of the bony structures leaving amputation as the only reasonable choice. New techniques using antibiotic impregnated bone grafts have proven efficient even under extreme circumstances. We report of their first application in apparently hopeless cases of rear foot infection.

Between 2004 and 2006 eight patients were operated because of florid infection of a severely destroyed rearfoot. In all cases the pre-treating surgeons suggested amputation below the knee as the only remaining possibility, which was refused by the patients. There were 3 men and 5 women. All patients had multiple surgery (min. 4, max. 72). The duration of infection was between 2 and 26 years. Diagnoses were: 4 St.p. open fracture, 2 Neuropathy, 1 Immunosuppression (kidney X), and 1 Rheumatoid arthritis.

Preoperative diagnostic measures included MRI and Bone Scans, localising the sites of infection. We performed radical debridement of all infected areas, intensive pulsed lavage, filling of defects with antibiotic bone compound (ABC) and stabilization using screws (4x) or the Ilizarov device (1x), respectively. Wounds could be closed primarily in 7 cases; in one case a fasciocutaneous suralis flap was necessary for closing. All patients were followed prospectively with a minimum period of 3 months and a maximum of 3 years.

Wound healing was completed uneventfully within 3 weeks. Surgery was always followed by a period of more than 6 months without any signs of infection. Re-intervention because of recurrence was necessary in 4 cases, whereas during all operations conditions were markedly improved compared to the foregoing intervention. So far 2 patients required 4 re-revisions of which one is awaiting a fifth revision, 1 patient one re-revision, and 1 patient decided to have the leg amputated. Six cases could be supplied with a custom-made shoe and were fully weight-bearing without pain or sign of infection at the last follow-up.

Reconstruction of the infected rearfoot is feasible even under extremely unfavourable conditions using antibiotic impregnated bone grafts. Fifty percent of cases may expect long-standing salvage with a weight-bearing limb. The other 50% must expect repeated surgery. It may be discussed, whether amputation in such cases could provide for a more favourable situation. However, we do believe that the decision for amputation shall be the sole decision of the patient. As long as the patient wants to keep his limb, being aware of all consequences thereafter, the surgeon is obliged to maintain the function of the foot as well as possible. Reconstruction with ABC seems to offer a promising tool for that purpose. So far 7 out of the 8 patients treated have been satisfied with the result and they would have it repeated in case of recurrence. They are aware that recurrence may occur but they should not show fear of the possibility of another revision since the hospital stays are short, discomfort is tolerable and rehabilitation is quick.

Infection of total hip replacement still is considered a devastating complication. One-stage revision, meaning complete removal of the implant and thorough debridement of the site together with the insertion of a new prosthesis during the same operation, is desirable because of improved rehabilitation of the patient and reduced costs. Although this method is known since more than 30 years it is not used widely yet because of several related risks: known methods rely on the use of antibiotic-loaded cement, which often has shown insufficient release of the added antibiotic. The carrier may even act as a bed for colonisation with selected bacteria. Osseous conditions presented during revisions prevent interconnection of the cement with the sclerotic bone. The toxic monomers of PMMA and heating during polymerisation causes necroses which may be origin of repeated loosening and new growth of bacteria. Filling the defects with cement provides unfavourable conditions in case of another revision, which has to be expected at a high percentage. To overcome these disadvantages uncemented techniques seem to be favourable.

After removal of the implants debridement is performed as in conventional septic surgery. After thorough cleaning and rinsing, bone voids are filled with bone graft using an impaction technique. We use allograft or xenograft bone that is free from antigenic material but intact structures of bone concerning collagen and mineral content. The bone is impregnated with high loads of antibiotic, using a specific incubation technique. There are two options of antibiotic impregnation: vancomycin (“V”) or tobramycin (“T”), the choice being dependent on the causative pathogen isolated. Combinations are possible in cases of mixed infections. The impregnation procedure guarantees high levels of antibiotics at the grafting site for several weeks during which the antibiotic is released into the surroundings. Systemic drug levels are usually undetectable. At the acetabular site we take care that the ground be sufficiently filled with antibiotic graft. Preferably an uncemented cup of hemispherical design is inserted. At the femoral site we prefer implants with a rectangular diameter. This design enables stable press fit contact with the shaft medially and laterally and leaves enough space for graft impaction at the posterior and anterior aspect of the endoprosthesis. Wounds are drained and closed immediately; rehabilitation is performed as after non-septic surgery.

Between 1998 and 2004 thirty-seven patients have been revised because of culture-proven infection of hip endoprosthesis. Causative pathogens were Coag.neg. staph (18x), S.aureus (11x), MRSA (4x), enterococci (9x) and other gram-positive pathogens (3x). In 6 hips gram-negative germs were found additionally. All hips could be followed up with a minimum of 2 years and a maximum of 8 years (mean: 4.1 years).

Wound healing was uneventful in all cases. Mean hospital stay was 16 days (10–32 days). Rehabilitation was in the range of uncomplicated primary THR in cases with short history of infection (up to 3 months) and prolonged in relation to duration of infection and amount of preceding surgery. In three hips there was recurrence of the infection, diagnosed between 6 and 12 weeks after surgery. In one of them the well-fixed stem had not been exchanged, in another one a technical error had occurred during impregnation of the bone graft. This one could be successfully re-operated using the same technique with appropriately impregnated bone graft, the other two were converted to a girdlestone situation. All other 32 hips showed no sign of infection until the last follow-up.

Bone processed in an adequate way represents an excellent carrier for vancomycin and tobramycin. With antibiotic graft compound eradication of pathogens, grafting of bony defects and re-insertion of an uncemented prosthesis may be accomplished in a single operation, making it an ideal tool in one stage non-cemented revision for infected total hip replacement. However, principles of septic surgery need to be observed. We now recommend removing even well-fixed prostheses and taking care, that we implant at least 50cc of well impregnated bone graft. Since the graft gradually is replaced by healthy own bone, improved conditions may be expected even in the case of another revision.

Infection of a total hip replacement (THR) requires component removal and thorough local debridement. Usually, long-term antibiotic treatment in conjunction with a two-stage revision is required. This may take several months. One-stage revision using antibiotic-loaded cement has not gained widespread use, although the clinical and economic advantages are obvious. Allograft bone may be impregnated with high levels of antibiotics, and in revision of infected THR, act as a carrier providing a sustained high local concentration.

We performed 37 one-stage revision of infected THRs, without the use of cement. There were three hips which required further revision because of recurrent infection, the remaining 34 hips (92%) stayed free from infection and stable at a mean follow-up of 4.4 years (2 to 8). No adverse effects were identified. Incorporation of bone graft was comparable with unimpregnated grafts.

Antibiotic-impregnated allograft bone may enable reconstruction of bone stock, insertion of an uncemented implant and control of infection in a single operation in revision THR for infection.

Aims: Infection of total hip replacement still is considered a devastating complication. One stage revision, meaning removal of implant and debris together with insertion of a new prosthesis during the same operation, reduces rehabilitation time and costs. To overcome the disadvantages of using cement, uncemented techniques seem to be favourable.

Methods: After removal of the implants debridement is performed as in conventional septic surgery. After thorough cleaning and rinsing, bone voids are filled with bone graft using an impaction technique. We use cancellous bone that is free from antigenic material but intact structures concerning collagen and mineral content. The bone is impregnated with high loads of antibiotic, using a proprietory incubation technique. There are two options of antibiotic impregnation: vancomycin or tobramycin. The impregnation procedure guarantees high levels of antibiotics at the grafting site for several weeks during which the antibiotic is released into the surrounding. Systemic drug levels usually are undetectable. Consequently an uncemented prosthesis is inserted. Wounds are drained and closed immediately, rehabilitation is performed as after non-septic surgery.

Between 1996 and 2003 35 patients have been revised because of culture proven infection of a hip endoprostheses. All hips could be followed with a minimum of 3months and a maximum of 6years.

Results: Wound healing was uneventful in all cases. Mean hospital stay was 16days (10–32days). In three hips there was recurrence of the infection, diagnosed between 6 and 12 weeks after surgery. One could be successfully re-operated using the same technique, the other two were converted to a girdlestone situation. All other 32 hips showed no sign of infection until the last follow up.

Conclusion: One stage non-cemented revision may provide an excellent solution for infected total hip replacement. However, several principles need to be observed. Bone processed in an adequate way represents an excellent carrier for vancomycin and tobramycin. Using an antibiotic graft compound eradication of pathogens, grafting of defects and re-insertion of an uncemented prosthesis may be accomplished in a one stage procedure. Since the graft gradually is replaced by healthy own bone, improved conditions may be expected even in the case of another revision.