Case Study of Emphysematous Osteomyelitis of Both Femoral Heads.

Early references of emphysematous osteomyelitis (EO) in the literature trace back to 1981, when the presence of intraosseous gas was mentioned in a paper of Ram et al.. Subsequently, 48 cases of EO were described. A significant underlying comorbidity was reported in most EO cases, especially diabetes and malignancy. This report presents a 37-year-old male with undiagnosed diabetes mellitus which was accompanied by emphysematous osteomyelitis of both femoral heads.

Successful disinfection of femoral head bone graft using high hydrostatic pressure.

The current standard for sterilization of potentially infected bone graft by gamma irradiation and thermal or chemical inactivation potentially deteriorates the biomechanical properties of the graft. We performed an in vitro experiment to evaluate the use of high hydrostatic pressure (HHP); which is widely used as a disinfection process in the food processing industry, to sterilize bone grafts. Four femoral heads were divided into five parts each, of which 16 were contaminated (in duplicate) with 105-107 CFU/ml of Staphylococcus epidermidis, Bacillus cereus, or Pseudomonas aeruginosa or Candida albicans, respectively. Of each duplicate, one sample was untreated and stored similarly as the treated sample. The remaining four parts were included as sterile control and non-infected control. The 16 parts underwent HHP at the high-pressure value of 600 MPa. After HHP, serial dilutions were made and cultured on selective media and into enrichment media to recover low amounts of microorganism and spores. Three additional complete femoral heads were treated with 0, 300 and 600 MPa HHP respectively for histological evaluation. None of the negative-control bone fragments contained microorganisms. The measured colony counts in the positive-control samples correlated excellent with the expected colony count. None of the HHP treated bone fragments grew on culture plates or enrichment media. Histological examination of three untreated femoral heads showed that the bone structure remained unchanged after HHP. Sterilizing bone grafts by high hydrostatic pressure was successful and is a promising technique with the possible advantage of retaining biomechanical properties of bone tissue.

Mycobacterium avium Complex Septic Arthritis Presenting as Osteonecrosis of the Femoral Head in a Patient With Systemic Lupus Erythematosus.

Mycobacterium avium complex is a rare cause of musculoskeletal infection, usually occurring in patients with compromised immune systems. Obtaining the diagnosis requires a high index of suspicion, and treatment can be delayed because of difficulty with isolating the organism. Treatment involves prolonged, targeted combination antibiotic therapy, and it is unclear whether eradication of the infection can occur in the presence of a foreign body, such as antibiotic spacers. The authors report a case of M avium infection presenting as presumed osteonecrosis of the femoral head in a young woman with systemic lupus erythematosus. She presented with collapse of her femoral head coinciding with several months of progressive, debilitating hip pain. She had mild fevers during that time, but results from multiple infectious workups, including hip aspiration, were negative. Purulent fluid was found in the operating room, but diagnosis was delayed for 5 weeks while waiting for cultures. The patient required 3 subsequent operations, eventually being left with a resection arthroplasty. Pertinent issues concerning diagnosis, therapy, and treatment challenges in M avium infections of the musculoskeletal system are discussed in this case report. [Orthopedics. 2017; 40(3):e549-e552.].

Lyophilized allogeneic bone tissue as an antibiotic carrier.

The rising number of primary joint replacements worldwide causes an increase of revision surgery of endoprostheses due bacterial infection. Revision surgery using non-cemented implants seems beneficial for the long-term outcome and the use of antibiotic-impregnated bone grafts might control the infection and give a good support for the implant. In this study we evaluated the release of antibiotics from fresh-frozen and lyophilized allogeneic bone grafts. Lyophilized bone chips and fresh frozen bone chips were mixed with gentamicin sulphate, gentamicin palmitate, vancomycin, calcium carbonate/calcium sulphate impregnated with gentamicin sulphate, and calcium carbonate/calcium sulphate bone substitute material impregnated with vancomycin. The efficacy of each preparation was measured by drug release tests and bacterial susceptibility using B. subtilis, S. aureus and methicillin-resistant Staphylococcus aureus. The release of gentamicin from lyophilized bone was similar to the release rate from fresh frozen bone during all the experimental time. That fact might be related to the similar porosity and microstructure of the bone chips. The release of gentamicin from lyophilized and fresh frozen bone was high in the first and second day, decreasing and keeping a low rate until the end of the second week. Depending on the surgical strategy either polymethylmethacrylate or allogeneic bone are able to deliver sufficient concentrations of gentamicin to achieve bacterial inhibition within two weeks after surgery. In case of uncemented revision of joint replacements allogeneic bone is able to deliver therapeutic doses of gentamicin and peak levels immediately after implantation during a fortnight. The use of lyophilized and fresh frozen bone allografts as antibiotic carriers is recommended for prophylaxis of bone infection.

Bacteremia with an iliopsoas abscess and osteomyelitis of the femoral head caused by Enterococcus avium in a patient with end-stage kidney disease.

A 70-year-old man on hemodialysis for end-stage kidney disease due to polycystic kidney disease presented with hip pain on extension and a high C-reactive protein level. Further examinations revealed an iliopsoas abscess and femoral head osteomyelitis caused by Enterococcus avium (E. avium) detected in blood and pus cultures. Complete resolution of the infection with ampicillin-resistant E. avium required six months of vancomycin therapy and two surgical drainage procedures. There have been no previous case reports in which both blood and abscess cultures confirmed E. avium infection. Careful attention should be paid to the detection of non-specific symptoms in patients on hemodialysis, with blood cultures being essential in such cases.

Swab or biopsy samples for bioburden testing of allograft musculoskeletal tissue?

Swab and biopsy samples of allograft musculoskeletal tissue are most commonly collected by tissue banks for bacterial and fungal bioburden testing. An in vitro study was performed using the National Committee for Clinical Laboratory Standards standard 'Quality control of microbiological transport systems' (2003) to validate and evaluate the recovery of six challenge organisms from swab and biopsy samples of allograft musculoskeletal tissue. On average, 8.4 to >100 and 7.2 to >100 % of the inoculum was recovered from swab and biopsy samples respectively. A retrospective review of donor episodes was also performed, consisting of paired swab and biopsy samples received in this laboratory during the period 2001-2012. Samples of allograft femoral heads were collected from living donors during hip operations. From the 3,859 donor episodes received, 21 paired swab and biopsy samples each recovered an isolate, 247 swab samples only and 79 biopsy samples only were culture positive. Low numbers of challenge organisms were recovered from inoculated swab and biopsy samples in the in vitro study and validated their use for bioburden testing of allograft musculoskeletal tissue. Skin commensals were the most common group of organisms isolated during a 12-year retrospective review of paired swab and biopsy samples from living donor allograft femoral heads. Paired swab and biopsy samples are a suitable representative sample of allograft musculoskeletal tissue for bioburden testing.

The effectiveness of bone banking in Central Serbia: audit of the first seven years.

We analyzed the incidence and predisposing factors for overall discard rate after retrieval of 295 femoral head allografts. The aim of the present study was to evaluate the quality system of institutional bone banking and to ensure that we can provide high standard allografts with low infection rate. Audit of bone banking was conducted on 295 donors and 180 recipients. Of the 295 donated femoral heads 77 were discarded, giving an overall discard rate of 26.1 %. At retrieval, 37 allografts were positive, giving an overall contamination rate of 12.54 %. The organism most commonly identified was Staphylococcus species. Seven (2.37 %) of the 295 allografts failed the blood screening tests. Twelve allografts (4.06 %) were discarded because of suspected damage of the packaging or disuse during surgery. Due to donor death or inability to perform serology retests, 21 (7.11 %) allografts were discarded. In the postoperative survey an infection rate of 2.22 % was found. After 7 years of bone banking, our results show that overall discard rate and allograft related infection rate are in accordance with the international standards. The leading cause of allograft discarding was bacterial contamination influenced by the surgical team. We suggest stringent aseptic allograft handling during harvesting and thawing within highly concentrated antibiotic solution to reduce a possibility of its contamination.

Reducing allograft contamination and disease transmission: intraosseous temperatures of femoral head allografts during autoclaving.

INTRODUCTION: The Singapore General Hospital Bone Bank, which exclusively stores femoral head allografts, relies on flash sterilisation to prevent allograft-related disease transmission and wound infection. However, intraosseous temperatures during autoclaving may be lower than required to eliminate human immunodeficiency virus, and hepatitis B and C viruses. The aim of this study is to determine the intraosseous temperatures of femoral head allografts during autoclaving and to assess the adequacy of autoclaving in preventing disease transmission. METHODS: Six femoral heads were acquired from patients who underwent hip arthroplasty. The specimens were divided into two groups. The first group underwent flash sterilisation with a sterilisation time of 4 min, while a longer sterilisation time of 22 min was used for the second group. RESULTS: The highest core temperature in the first group was 130°C, while the core temperatures in the second group plateaued at 133°C for all allografts. In the first group, only smaller allografts maintained temperatures sufficient for the inactivation of the clinically relevant viral pathogens. In contrast, all allografts in the second group were terminally sterilised. CONCLUSION: There is an inverse correlation between the size of allografts and intraosseous temperatures achieved during autoclaving. Therefore, we recommend dividing large allografts into smaller pieces, in order to achieve intraosseous temperatures adequate for the elimination of transmissible pathogens during flash sterilisation. Allografts should not be terminally sterilised, as the resulting allografts will become unusable. Despite modern processing techniques, stringent donor selection remains vital in the effort to prevent allograft-related infections. Autoclaving is an economical and efficacious method of preventing allograft-related disease transmission.

Comparison of the efficiency of different antibiotic irrigation solutions in decontamination of allografts contaminated with Staphylococcus aureus.

OBJECTIVE: The purpose of this study was to investigate the local antibacterial efficacy of saline, rifampicin, gentamicin, high-concentration fusidic acid and low-concentration fusidic acid in the decontamination of allografts contaminated with Staphylococcus aureus. METHODS: Fifty-five sterile, fresh-frozen femoral heads obtained from the bone bank were contaminated with methicillin-sensitive ATCC 25923 Staphylococcus aureus. Samples were divided into groups and debrided with high-pressure (80 psi) pulse lavage using a saline, rifampicin irrigation solution (50 mg/l), gentamicin irrigation solution (50 mg/l) and low- (50 mg/l) or high-concentration (500 mg/l) fusidic acid irrigation solution for 30 seconds from a distance of 10 cm. After irrigation, allografts were incubated in the culture and developed colonies were counted. Mean±standard deviation (min-max) values were calculated. The differences between the four irrigation groups were evaluated using the Kruskal-Wallis variance analysis and groups were compared two at a time using the post-hoc Mann-Whitney U test. RESULTS: No colonization was detected with the exception of one allograft in the rifampicin irrigation group. The gentamicin irrigation group had similar results as the high-concentration fusidic acid irrigation group and both results were superior to those of the saline and low-concentration fusidic acid irrigation groups (p=0.010 and 0.004, respectively). The low- and high-concentration fusidic acid irrigation groups were similar and were not shown to have superior results than saline irrigation group. CONCLUSION: Rifampicin irrigation solution was the most effective in the decontamination of allografts previously contaminated with Staphylococcus aureus. Gentamicin, high-concentration fusidic acid, low-concentration fusidic and saline irrigation solutions may also be used respectively, according to their effectiveness.

Microbiological culture findings of the femoral heads as a prognostic factor in the total hip replacement surgery.

BACKGROUND: In primary total hip replacements (THRs), the dissected femoral heads (FHs) are commonly used to make the bone-chips for the reconstruction in the orthopaedic surgery. The donated FHs are routinely microbiologically cultured to identify and contaminated FHs are discarded. This study examines whether a positive FH culture predicts an infection and prosthetic failure after primary THR. METHODS: The study sampled 274 donated FHs from patients with osteonecrosis (ON), hip joint osteoarthritis (OA), and femoral neck fracture (FNF) in THR to culture the microbes. The FH contamination rates were analyzed for ON, OA, and FNF groups. Proportion of the postoperative infection or prosthetic failure in the group of donors with a positive FH culture were compared to the proportion in the group of donors with a negative FH culture. RESULTS: The rates of the positive culture in the ON, OA, and FNF groups were 7.1%, 3.8%, and 4.0%, respectively. The infection rate was found to be non-significantly greater in the ON group than in the OA and FNF groups. In the negative culture group, one patient (0.63%) had a postoperative superficial infection, and five patients (3.2%) experienced additional surgeries including a fixation for a periprosthetic fracture, within a minimum follow-up of two years. However, no postoperative infection was encountered, and no revision surgery was required in the positive culture group. CONCLUSIONS: A positive FH culture is not always associated with elevated risks of infection or prosthetic failure after THR. Therefore, such finding cannot be used as a prognostic factor of THR. The FHs that return a positive culture may not lead to the orthopaedic assessment of an infection or other postoperative complication risks in primary THR.

Comparison of contamination of femoral heads and pre-processed bone chips during hip revision arthroplasty.

With bone impaction grafting, cancellous bone chips made from allograft femoral heads are impacted in a bone defect, which introduces an additional source of infection. The potential benefit of the use of pre-processed bone chips was investigated by comparing the bacterial contamination of bone chips prepared intraoperatively with the bacterial contamination of pre-processed bone chips at different stages in the surgical procedure. To investigate baseline contamination of the bone grafts, specimens were collected during 88 procedures before actual use or preparation of the bone chips: in 44 procedures intraoperatively prepared chips were used (Group A) and in the other 44 procedures pre-processed bone chips were used (Group B). In 64 of these procedures (32 using locally prepared bone chips and 32 using pre-processed bone chips) specimens were also collected later in the procedure to investigate contamination after use and preparation of the bone chips. In total, 8 procedures had one or more positive specimen(s) (12.5 %). Contamination rates were not significantly different between bone chips prepared at the operating theatre and pre-processed bone chips. In conclusion, there was no difference in bacterial contamination between bone chips prepared from whole femoral heads in the operating room and pre-processed bone chips, and therefore, both types of bone allografts are comparable with respect to risk of infection.

Biofilm formation by staphylococci on fresh, fresh-frozen and processed human and bovine bone grafts.

Biofilm formation is a multi-step process influenced by surface properties. We investigated early and mature biofilm of Staphylococcus aureus on 4 different biological calcium phosphate (CaP) bone grafts used for filling bone defects. We investigated standardised cylinders of fresh and fresh-frozen human bone grafts were harvested from femoral heads; processed humanand bovine bone grafts were obtained preformed. Biofilm formation was done in tryptic soy broth (TSB) using S. aureus (ATCC 29213) with static conditions. Biofilm density after 3 h (early biofilm) and 24 h (mature biofilm) was investigated by sonication and microcalorimetry. After 3 h, bacterial density was highest on fresh-frozenandfresh bone grafts. After 24 h, biofilm density was lowest on freshbone grafts (p < 0.001) compared to the other 3 materials, which did not differ quantitatively (p > 0.05). The lowest increase in bacterial density was detected on fresh bone grafts (p < 0.001). Despite normal shaped colonies, we found additional small colonies on the surface of the fresh and fresh-frozen samples by sonication. This was also apparent in microcalorimetric heat-flow curves. The four investigated CaP bone grafts showed minor structural differences in architecture but marked differences concerning serum coverage and the content of bone marrow, fibrous tissue and bone cells. These variations resulted in a decreased biofilm density on freshand fresh-frozenbone grafts after 24 h, despite an increased early biofilm formation and might also be responsible for the variations in colony morphology (small colonies). Detection of small colony variants by microcalorimetry might be a new approach to improve the understanding of biofilm formation.

Chlamydia pneumoniae and osteoporosis-associated bone loss: a new risk factor?

UNLABELLED: We found an association between the presence of Chlamydia pneumoniae DNA both in osteoporotic bone tissue and peripheral blood mononuclear cells (PBMCs) and the increase in circulating resorptive cytokines. INTRODUCTION: Our study was designed to determine whether C. pneumoniae infection may be involved in osteoporosis-associated bone loss. METHODS: The study included 59 women undergoing hip joint replacement surgery for femoral neck fracture: 32 with osteoporosis and 27 with osteoarthritis. A total of 118 tissue specimens (59 bone tissues, 59 PBMCs) were examined for C. pneumoniae DNA by real-time polymerase chain reaction (PCR). Serum levels of soluble receptor activator of nuclear factor kappa B ligand (sRANKL), osteoprotegerin (OPG), interleukin (IL)-1ß, tumor necrosis factor-α, and IL-6 were also measured. RESULTS: C. pneumoniae DNA was detected in osteoporotic bone tissue whereas it was not found in non-osteoporotic bone tissue (p < 0.05). A significantly higher rate of C. pneumoniae DNA (p < 0.05) was found in PBMCs of osteoporotic patients than in those of osteoarthritis patients. Among osteoporotic patients, serum sRANKL, IL-1, and IL-6 concentrations as well as sRANKL/OPG ratio significantly differ between patients with bone tissue and PBMCs positive to C. pneumoniae and C. pneumoniae-negative patients. CONCLUSION: The association between the presence of C. pneumoniae DNA, both in bone tissue and PBMCs, and the increase in sRANKL/OPG ratio as well as in IL-1ß and IL-6 levels observed in osteoporotic patients suggests C. pneumoniae infection as a new risk factor for osteoporosis.

Effect of two cleaning processes for bone allografts on gentamicin impregnation and in vitro antibiotic release.

Bone allografts are a useful and sometimes indispensable tool for the surgeon to repair bone defects. Microbial contamination is a major reason for discarding allografts from bone banks. To improve the number of safe allografts, we suggest chemical cleaning of the grafts followed by antibiotic impregnation. Comparison of two chemical cleaning processes for bone allografts aiming for antibiotic impregnation and consequently delivery rates in vitro. Bone chips of 5-10 mm were prepared from human femoral heads. Two cleaning methods (cleaning A and cleaning B) based on solutions containing hydrogen peroxide, paracetic acid, ethanol and biological detergent were carried out and compared. After the cleaning processes, the bone chips were impregnated with gentamicin. Bacillus subtilis bioassay was used to determine the gentamicin release after intervals of 1-7 days. Differences were compared with non-parametric Mann-Whitney U tests. The zones of inhibition obtained from the bone grafts cleaned with both cleaning processes were similar between the groups. The concentration of the released antibiotic was decreasing gradually over time, following a similar pattern for both groups. The cleaning procedure A as well as the cleaning procedure B for bone allografts allowed the impregnation with gentamicin powder in the same concentrations in both groups. The delivery of gentamicin was similar for both groups. Both cleaning procedures were easy to be carried out, making them suitable for routine use at the bone banks.

Microbiological Culture Findings of the Femoral Heads as a Prognostic Factor in the Total Hip Replacement Surgery

BACKGROUND: In primary total hip replacements (THRs), the dissected femoral heads (FHs) are commonly used to make the bone-chips for the reconstruction in the orthopaedic surgery. The donated FHs are routinely microbiologically cultured to identify and contaminated FHs are discarded. This study examines whether a positive FH culture predicts an infection and prosthetic failure after primary THR. METHODS: The study sampled 274 donated FHs from patients with osteonecrosis (ON), hip joint osteoarthritis (OA), and femoral neck fracture (FNF) in THR to culture the microbes. The FH contamination rates were analyzed for ON, OA, and FNF groups. Proportion of the postoperative infection or prosthetic failure in the group of donors with a positive FH culture were compared to the proportion in the group of donors with a negative FH culture. RESULTS: The rates of the positive culture in the ON, OA, and FNF groups were 7.1%, 3.8%, and 4.0%, respectively. The infection rate was found to be non-significantly greater in the ON group than in the OA and FNF groups. In the negative culture group, one patient (0.63%) had a postoperative superficial infection, and five patients (3.2%) experienced additional surgeries including a fixation for a periprosthetic fracture, within a minimum follow-up of two years. However, no postoperative infection was encountered, and no revision surgery was required in the positive culture group. CONCLUSIONS: A positive FH culture is not always associated with elevated risks of infection or prosthetic failure after THR. Therefore, such finding cannot be used as a prognostic factor of THR. The FHs that return a positive culture may not lead to the orthopaedic assessment of an infection or other postoperative complication risks in primary THR.

Simple novel bone bank storage: the Singapore General Hospital experience.

INTRODUCTION: Since 1981, the Singapore General Hospital (SGH) bone bank has proven to be a safe, reliable, and economical source of bone allografts. Femoral heads are used exclusively and are procured from patients undergoing hip arthroplasty. Screening for HIV, hepatitis B, and hepatitis C is carried out prior to surgery. Patients with ongoing infection and past history of malignancy are excluded. The bone graft procured is washed and autoclaved to 134°C for 3 minutes. It is then stored in saline solution containing penicillin and streptomycin at -80°C. Based on our experience, such a system can be readily duplicated in developing nations with minimal cost and equipment. This article presents our experience in the procurement and storage of femoral head allografts with clinical results to support the safety profile. METHODS: Ten femoral heads were harvested from patients who underwent hip arthroplasty. The femoral heads were autoclaved and stored at -80°C in an antibiotic solution. Bone chips were sent for culture immediately after autoclaving and at 3 and 6 months. RESULTS: All specimens passed the initial sterility testing and remained sterile up to 6 months. A retrospective study of 9 patients who had 13 allografts implanted between 2008 and 2010 showed that none of the recipients acquired an infection or transmissible disease due to the allografts. CONCLUSION: This study showed that our protocol allows for procurement of femoral head allografts with minimal contamination and that they can maintain sterility for up to 6 months. This finding is further supported by our clinical results. Hence, this protocol will be useful for bone banks in developing nations where sterility conditions are suboptimal and cost is an issue.

Screening femoral heads from living donors: a prospective study comparing swab-agar versus bone fragment-broth culture.

Femoral heads are an important source of allograft bone used in reconstructive orthopaedic surgery. The sterility of donor material is of major importance for the recipient. Femoral heads intraoperatively retrieved during hip arthroplasty from medically screened living donors are routinely checked with a surface swab to exclude microbiological contamination. There is, however, evidence that swab cultures have limited sensitivity. We therefore prospectively compared two ways of screening femoral heads. Bacterial recovery from swabs in Amies transport medium taken intraoperatively, subsequently transported to the microbiology laboratory and inoculated on agar and in broth was compared with the recovery from a bone fragment also taken intraoperatively but immediately inoculated into Wilkins Chalgren broth. Forty femoral heads were tested with both methods. Bacteria were cultured neither from the femoral surface swabs nor from the femoral fragments. Consequently no distinct conclusions regarding the sensitivity of both techniques could be drawn. In addition the bacterial yield of two swabs in Amies transport medium streaked on a variety of culture media other than the conventional agar plates was also studied. Culturing of these swabs resulted in the detection of bacteria that are predominantly considered contaminants.

Long-term outcome of total hip replacement in patients with or without femoral head contamination.

PURPOSE: To compare long-term outcomes of total hip replacement (THR) in patients with or without contamination of the femoral head. METHODS: After a mean period of 12 (range, 8-17) years, 104 female and 71 male THR patients aged 47 to 96 (mean, 77) years were reassessed via a self-administered questionnaire, and 25 other THR patients were reassessed by review of case notes. The questionnaires comprised the 12-item Oxford hip score and the European Quality Of Life (EuroQOL). 87 and 88 patients had positive and negative cultures in the donated femoral heads, respectively. The 2 groups were compared with respect to the Oxford hip score, the EuroQOL, and rates of complication and revision surgery. RESULTS: Long-term outcomes of THR patients with or without femoral head contamination were not significantly different. Respectively, the mean Oxford hip scores were 36 and 39 (p=0.4); 16 and 14 patients had the maximum score of 48; 2 and 3 patients scored <10 (mostly owing to aseptic loosening). The respective mean visual analogue scale score of the EuroQOL were 65 and 73 (p=0.07); only the dimension of self care was significantly different between groups (p=0.04). Respectively, 14 and 12 patients had complications (16% vs. 15%, χ²=0.05, p=0.8), whereas 11 and 5 patients had revision surgery (13% vs. 6%, χ²=2.2, p>0.1). CONCLUSION: Microbiological screening of donated femoral heads plays no role in predicting long-term failure of THR in the donors.

Bioburden assessment of banked bone used for allografts.

Allograft bone is commonly used in reconstructive orthopaedic surgery and needs to be assessed for bioburden before transplant. The Microbiology Department of the South Eastern Area Laboratory Services (SEALS), located at the St. George Hospital, Sydney, has provided this service to the New South Wales (NSW) Bone Bank. This study reviewed the organisms isolated from femoral head allografts of living donors from the NSW Bone Bank over a 7-year period. It was found that growth was reported from 4.9% of samples with the predominant organism being coagulase-negative staphylococci. This review will focus on the micro-organisms isolated, the interaction of the laboratory with the bone bank, the relevance of the bioburden assessment in the overall quality process and patient safety.