Cell Tissue Bank DOI 10.1007/s10561-014-9426-0
ORIGINAL PAPER
The effectiveness of bone banking in Central Serbia: audit of the first seven years Zeljko Lj Stepanovic • Branko M Ristic
Received: 7 September 2013 / Accepted: 5 February 2014 Ó Springer Science+Business Media Dordrecht 2014
Abstract 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 Z. L. Stepanovic (&) B. M. Ristic Department of arthroplasty, Clinic for Orthopaedic and Trauma Surgery, Clinical Center Kragujevac, Zmaj Jovina 30, 34000 Kragujevac, Serbia e-mail: [email protected] Z. L. Stepanovic B. M. Ristic Faculty of Medical Science, University of Kragujevac, Svetozara Markovica 69, 34000 Kragujevac, Serbia
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. Keywords Bone banking Bone transplantation Femoral head allograft Allograft discarding Swab cultures Bacterial contamination
Introduction Many orthopaedic reconstructive procedures imply the frequent use of bone allografts. In most cases, these procedures are complex and time consuming. There is a potential risk for disease transmission if the bone allograft is contaminated (Tomford et al. 1990; Journeaux et al. 1999; Barnhart et al. 2009). Femoral head allografts retrieved at primary total hip arthroplasty (THA) are the most frequently used. Internal hospital bone banks are the most widely accepted source of supplying allogenic bone grafts. They are responsible for collecting, testing and storing of these allografts according to stringent protocols (Kappe et al. 2010). At donation, cultures are taken to exclude bacterial contamination of the femoral head, which is then stored in a fresh-frozen fashion from -70 °C to -80 °C. There are several methods used to obtain
123
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culture specimens, such as surface swab, joint swab, and bone or tissue biopsy. Between 1 and 22 % of the donated bone grafts are found to be contaminated and discarded. Most of the bone banks use swab cultures and bone biopsy immediately before implantation procedure, although there are no clinical evidence for their justification (Barnhart et al. 2009; Sommerville et al. 2000; James et al. 2004). It is mandatory for any bone bank to provide high quality measures to prevent contamination of bone allografts during retrieval and storing, particularly when sterilization procedures are not applied (Pruss et al. 2003). The bone bank unit at the Clinic for Orthopaedic and Trauma Surgery, Clinical Center Kragujevac, Central Serbia, was established in 2006. Its methods are based on the principles of the American Association of Tissue Banks (AATB 1992) and the European Association of Musculo-Skeletal Transplantation (EAMST 1997). This is the first audit of the institutional bone bank performance conducted over the past 7 years. The aim of the present study was to evaluate the quality system of bone banking and to ensure that we can provide high standard allografts with low infection rate.
Materials and methods Between January 2007 and May 2013, femoral head allografts were retrieved from a total of 295 patients aged between 36 and 90 years. Femoral heads were taken from those with fresh femoral neck fracture or after primary THA. Bone donation was voluntary and no financial or other benefits were granted. Informed consent was obtained, and a detailed history was taken to exclude malignancy, systemic and infectious diseases. Potential donors with severe degenerative changes or osteoporosis of femoral head were excluded from tissue procurment. The allografts are utilized to meet our own demands in orthopaedic and trauma procedures. The allografts were retrieved in the conventional orthopaedic theatre under aseptic conditions by ten orthopaedic surgeons. Furthermore, a prophylactic antibiotic (cefuroxime, 1.5 g or cefazoline 1.0 g) was given 30 min before surgery. The femoral head was released from soft tissues and two swab samples were taken by the main surgeon: one from the surgical site and the other one from the femoral head itself. After determining its size, the graft
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was placed into a sterile plastic container by the surgeon. The container was sealed tightly, immediately isolated with two sterile separate bags, labeled and stored in a freezer at -70 °C within 30 min. Swab samples were sent to hospital laboratory for microbiological evaluation. Two cultures of aerobic and anaerobic microorganisms in blood agar, MacConkey agar, and chocolate blood agar were analyzed. The donors were tested for hepatitis B (HBs-antigen and anti HBc-antibodies) and C (HCV-antibodies and HCV-RNA), HIV (HIV1/2 antibodies) and syphilis (Treponema pallidum hemagglutination titre) at donation and at 6 months after surgery, according to the bone bank protocol. We always provide corresponding blood type grafts for recipients and Rh-compatible grafts to Rh-negative patients to prevent immunization (Meermans et al. 2007). All the blood test results at retrieval were documented in the donors’ bone bank records. These data are then filed in our bone bank inventory. A computerized record of each donor and recipient is also kept as a back-up system. These logs are regularly updated and checked by authorized bone bank personnel. We do not perform histopathological evaluation of femoral heads retrieved from living donors. The allografts that failed the selection criteria or were found to be contaminated have been discarded. Those that passed the screening tests were ready for use 6 months after admission. Bone allografts regarded acceptable are stored for a maximum of 5 years. Before application, the allograft is thawed in 500 ml of 0.9 % warm sterile saline with 1000 mg of amikacin. Intra-operative allograft cultures were not performed because there are no clinically relevant indicators that such culturing would assure any association between postoperative wound infection and positive intra-operative allograft cultures (Barnhart et al. 2009; Winter et al. 2005).
Results Over the past 7 years, we performed a total of 749 primary THA and 683 hemiarthroplasties. Due to strict selection criteria, only 11.85 % (81/683) of patients with fresh femoral neck fracture and 28.57 % (214/ 749) with hip osteoarthrosis met bone bank standards. Of the 295 retrieved femoral heads, 214 (72.54 %) were retrieved after primary THA and 81 (27.46 %) after femoral neck fracture. The bone allografts were
Cell Tissue Bank Table 1 Type and number of surgical procedures with fresh frozen femoral head allograft
Table 2 Organisms cultured from allograft bone retrieved (number of positive cultures)
Type of the procedure
Microorganism
Number of procedures
Coagulase-negative staphylococcus
Number of cultures 9 (24.32 %)
Revision total hip arthroplasty
36 (18.56 %)
Staphylococcus aureus
5 (13.51 %)
Primary total hip-and-knee arthroplasty
15 (7.73 %)
Staphylococcus epidermidis
6 (16.22 %)
Reconstructive surgery after failed fixation in trauma patients
50 (25.78 %)
Streptococcus viridans
2 (5.40 %)
Fixation of upper-limb fractures
13 (6.70 %)
Enterococcus faecalis
3 (8.11 %)
Fixation of lower-limb fractures
70 (36.08 %)
Gram-positive anaerobic cocci (GPAC)
5 (13.51 %)
Proteus mirabilis
2 (5.40 %)
Miscellaneous surgeries Total
10 (5.15 %) 194 (100 %)
retrieved from 110 men and 185 women. The mean age of donors after primary THA was 64 (36–80) years compared to 73 (45–90) years in donors with fractured femoral neck. A total of 194 (65.76 %) non-contaminated allografts were implanted by the end of the study (Table 1). The overall allograft discard rate was 26.1 %. The leading cause of allograft discarding was bacterial contamination. At retrieval, 37 allografts were positive for at least one micro-organism, giving an overall contamination rate of 12.54 %. The majority of these allografts were contaminated with bacteria commonly found on the skin (Table 2). Swab cultures of the surgical site were negative in all 37 donors. No surgical site infection was recorded in those patients during the mean follow-up period of 44 months (10–76). Seven (2.37 %) of the 295 allografts failed the blood screening tests and were thus discarded. One patient was false HIV positive, two were hepatitis C positive and four were with hepatitis B. Twelve allografts (4.06 %) were discarded because of suspected damage of the packaging or disuse during surgery. Due to death of the donor or inability to perform serology retests, 21 (7.11 %) allografts were discarded 180 days after admission. The remaining 28 allografts (9.49 %) are still stored in the bone bank. One hundred and ninety-four allografts were implanted to 180 recipients (maximum four allografts were used for one patient), of whom 69 were male and 111 were female. Mean age was 51 (18–86) years for male recipients and 68 (17–87) years for female population. Four out of 180 (2.22 %) patients developed deep postoperative wound infections. All infections occurred in trauma patients treated for distal
Acinetobacter species
2 (5.40 %)
Bacilus subtilis
1 (2.70 %)
Pseudomonas aeruginosa
1 (2.70 %)
Providencia species
1 (2.70 %)
Total
37 (100 %)
femoral fracture, tibial plateau fracture and two high energy calcaneal fractures. Staphylococcus species was isolated in three of four surgical site infections. In five recipients (2.77 %) the allograft incorporation was unsuccessful.
Discussion In the present study, we have reviewed the bone banking activities in the Clinical Center Kragujevac, Central Serbia, over the period of 7 years. There was a total of 295 (20.6 %) living donors among 1432 patients who were treated by hemiarthroplasty and primary THA. In other reports this ratio was between 15 and 60 % (Kappe et al. 2010; Phuong et al. 2013). According to donor selection criteria potential donors with severe degenerative changes or osteoporosis of femoral head were excluded from tissue harvesting. Therefore, there is no strong evidence that failures in allograft bone incorporation were attributed to poor quality of femoral heads retrieved from the bone bank. For this we accused accentuated immune response and poor vascularity of the host bone due to severe trauma and repetitive surgeries. In most reports, allograft discarding resulted from incidents at the time of its harvesting or from inabilities to perform the 6-month serology retests of donors (Winter et al. 2005; Hou and Yang 2005). The overall discard rate was 17–33 % in earlier reports (Hou and Yang 2005; Ivory and Thomas 1993; Nielsen
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Cell Tissue Bank Table 3 Contamination rate in live donors
Retrieved allografts
Contaminated allografts
Study
Contamination rate (%)
Specimen
Used allografts
Serum postive allografts
Tomford et al. (1990)
11.8
Bone swab
70
Packaging failure
60
Journeaux et al. (1999)
13
Bone swab ? bone biopsy
Sommerville et al. (2000)
22
Bone swab ? joint swab ? bone biopsy
Sommerville et al. (2000)
12.9
Ivory and Thomas (1993)
1.2
Bone swab
Bone biopsy
Saies and Davidson (1990)
17
Joint swab ? bone biopsy
Chiu et al. (2004)
9.3
Bone biopsy
van de Pol et al. (2007)
6.4
Bone biopsy
et al. 2001). In evaluation performed by the Canadian Council for Donation and Transplantation, the average combined discard and deferral rate reported by large, well-established hospital bone banks was 49 % (CCDT 2006). In our series, the overall discard rate of 26 % was comparable with other hospital bone banks. The leading cause of allograft discarding was bacterial contamination. The germs most commonly identified in swab cultures at graft retrieval were Staphylococcus species which compared similarly with other studies (Journeaux et al. 1999; Vehmeyer et al. 2002; Deijkers et al. 1997). In this study, the contamination rate of allografts during harvest of the femoral heads was 12.54 %. Table 3 shows a comparison of rates in other reports. We used only swab culture to screen bacterial contamination of bone grafts. However, the swab culture had been proven inadequate to detect bacterial contamination of musculoskeletal allografts due to low sensitivity. It was found that the swab cultures after thawing were different from the wound cultures in most of the infected patients. It suggests that the allograft itself may not transmit the infection from donor to recipient (Hou and Yang 2005; Vehmeyer et al. 2002). Previous studies were unable to identify any association between positive intra-operative allograft cultures and the development of post-operative wound infection (Barnhart et al. 2009; Winter et al. 2005). The unacceptable 28.57 % (6/21) of contaminated femoral heads during the first year of harvesting was
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50 40 30 20 10 0
2007
2008
2009
2010
2011
2012
2013
Fig. 1 The ratio between used and discarded allografts due to bacterial contamination, serum positive donors and packaging errors
due to problems with graft handling and inexperience (Fig. 1). Swab cultures and allograft handling was predominantly performed by scrub nurse. To avoid handling problem and responsibility, we decided that femoral heads should be swabbed and stored in container only by the main surgeon. We reduced the time between the osteotomy and storing of the allograft. We strived to exclude contact with allograft by using the reduction forceps. This measures resulted in reduction of bacterial contamination from 18.33 % in 2008 to 10.63 % in 2009 and 6.52 % in 2010. In next 2 years we recorded 17.64 and 5.17 % of contaminated bone allografts respectively. In the past 4 months of 2013 none of the femoral head allografts have been discarded from the bank. Evident reduction of contamination rate after the first year of the bone banking suggests that such problem can be prevented by strict adherence to quality measures, aseptic technique and careful allograft handling in the operating theatre. In the postoperative survey no obvious correlation was determined between infection and positive microbiological results of bone swab cultures. No infection was recorded in the postoperative follow-up among 37 donors whose femoral heads were discarded due to contamination. In recent report, no significant difference in the long-term outcome of total hip replacement in patients with or without femoral head contamination was found (Ibrahim et al. 2011). With prophylactic antibiotic administration before surgery, it is unlikely that bacteria of high virulence will hematogenously contaminate femoral heads. Femoral heads
Cell Tissue Bank
are contaminated either via air with skin flora from the operating room personnel and the environment (which was the scenario in our report) or per continuitatem with germs originating from skin of the donor. The entire surface of the femoral head can be sampled for culture swabs, although the contamination may not always be evenly spread over the allograft. Several studies doubt the cost effectiveness and necessity of routine histopathological examination. Tissue specimens can only be taken from a limited number of sites. It is therefore unlikely that tissue cultures would provide additional information (Vehmeyer et al. 2002). However, it is unclear whether the results after the use of multiple specimens reflect the true contamination rates (Zwitser and van Royen 2011). The AATB and the EAMST have excluded these tests in their standard screening protocol and currently we do not use them either (AATB 1992; EAMST 1997). Wound infection after bone allograft transplantation is a potentially devastating complication. It may lead to repetitive surgery, long-term antibiotic administration, poor patient outcome, and may have medicolegal implications. The use of sterilization techniques, antibiotics and histopathology is controversial. Attempts to achieve the perfect sterilization technique continue, but currently the safest method appears to be aseptic harvesting with strict monitoring (Meermans et al. 2007; Hou and Yang 2005; Deijkers et al. 1997). Fortunately, reported surgical site infection as a consequence of contaminated bone allograft is infrequent and ranges between 1.6 and 12 % (Kappe et al. 2010; Winter et al. 2005; Nielsen et al. 2001; Chiu et al. 2004; van de Pol et al. 2007; Sutherland et al. 1997). In our study, we recorded 2.22 % allograftrelated surgical site infections. The low infection rate and high allograft discard rate may indicate the effectiveness of the quality system monitoring in our institution. Recent studies issued the same conclusion that isolates grown from the culture after thawing were different from those isolated from the infected wound. The most of the recipients who received contaminated allografts were clinically with no sign of infection. This raises the question of justification of taking the swab and bone cultures after allograft thawing. Even positive swab cultures do not predict the development of infection in the recipient (Barnhart et al. 2009; Winter et al. 2005; Chiu et al. 2004). Our findings indicate that the highest risk of allograft contamination exists during its harvesting and thawing. Even
processed allograft may become contaminated during final application. Thus immersion of sterile allograft in saline solution with high doses of bactericidal antibiotics (such as amikacin) may act as secondary sterilization and prevent its superficial contamination. In conclusion, after 7 years of bone banking, our results show that overall discarding and infection rate after bone allotransplantation are in accordance with the international standards. The existing methods used in evaluation of bone allograft sterility are not sufficiently reliable. The leading cause of allograft discarding was bacterial contamination influenced by the surgical team. The contamination liability during bone allograft handling induced us to develop an optimal handling technique. We suggest stringent aseptic allograft handling during harvesting and thawing within highly concentrated antibiotic solution to reduce a possibility of its contamination.
References American Association of Tissue Banks (1992) Technical manual for tissue banking. AATB Barnhart B, Allan DG, Milbrandt JC, Khardori N, Hall A, Barenfanger J (2009). Intra-operative culturing of donor allograft bone: a lack of clinical utility. U Pa Orthop J. http://upoj.org/site/files/v19/v19_10.pdf Chiu CK, Lau PY et al (2004) Microbial contamination of femoral head allografts. Hong Kong Med J 10(6):401–405 Deijkers RLM, Bloem RM, Petit PLC, Brand R, Vehmeyer SBW, Veen MR (1997) Contamination of bone allografts: analysis of incidence and predisposing factors. J Bone Joint Surg (Br) 79(1):161–166 EAMST, EATB (1997) Common standards for musculo-skeletal tissue banking. European Association for Musculoskeletal Transplantation and European Association of Tissue Banks, Vienna Hou CH, Yang RS (2005) Hospital-based allogenic bone bank—10-year experience. J Hosp Infect 59:41–45 Ibrahim T, Aswad MG, Dias JJ, Brown AR, Esler CN (2011) Long-term outcome of total hip replacement in patients with or without femoral head contamination. J Orthop Surg (Hong Kong) 19(2):174–176 Ivory JP, Thomas IH (1993) Audit of a bone bank. J Bone Joint Surg Br 75:355–357 James LA, Ibrahim T, Esler CN (2004) Microbiological culture results for the femoral head. Are they important to the donor? J Bone Joint Surg Br 86(6):797–800 Journeaux SF, Johnson N, Bryce SL, Friedman SJ, Sommerville SM, Morgan DA (1999) Bacterial contamination rates during bone allograft retrieval. J Arthroplast 14(6):677–681 Kappe T, Cakir B, Mattes T, Reichel H, Flo¨ren M (2010) Infections after bone allograft surgery: a prospective study by a hospital bone bank using frozen femoral heads from living donors. Cell Tissue Bank 11:253–259
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Cell Tissue Bank Meermans G, Roos J, Hofkens L, Cheyns P (2007) Bone banking in a community hospital. Acta Orthop Belg 73:754–759 Nielsen HT, Larsen S, Andersen M, Ovesen O (2001) Bone bank service in Odense, Denmark. Audit first ten years with bone banking at the Department of Orthopaedics, Odense University Hospital. Cell Tissue Bank 2:179–183 Phuong DT, Park KS, Hwang SY, Lee DH, Yoon TR (2013) Microbiological culture findings of the femoral heads as a prognostic factor in the total hip replacement surgery. Clin Orthop Surg 5(2):105–109. doi:10.4055/cios.2013.5.2.105 Pruss A, Seibold M, Benedix F et al (2003) Validation of the ‘‘Marburg bone bank system’’ for thermodisinfection of allogenic femoral head transplants using selected bacteria, fungi, and spores. Biologicals 31(4):287–294 Saies AD, Davidson DC (1990) Femoral head allograft bone banking. Aust N Z J Surg 60:267–270 Sommerville SM, Johnson N, Bryce SL et al (2000) Contamination of banked femoral head allograft: incidence, bacteriology and donor follow up. Aust N Z J Surg 70(7):480–484 Sutherland AG, Raafat A, Yates P et al (1997) Infection associated with the use of allograft bone from the North East Scotland Bone Bank. J Hosp Infect 35:215–222
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The Canadian Council for Donation and Transplantation (CCDT) (2006) Evaluation of surgical bone banking and utilization in Canada. http://www.ccdt.ca. September 2006 Tomford WW, Thongphuasuk J, Mankin HJ, Ferraro MJ (1990) Frozen musculoskeletal allografts: a study of the clinical incidence and causes of infection associated with their use. J Bone Joint Surg (Am) 72(8):1137–1143 van de Pol GJ, Sturm PD, van Loon CJ, Verhagen C, Schreurs BW (2007) Microbiological cultures of allografts of the femoral head just before transplantation. J Bone Joint Surg Br 89(9):1225–1228 Vehmeyer SBW, Slooff RMA, Bloem RM, Petit PLC (2002) Bacterial contamination of femoral head allografts from living donors. Acta Orthop Scand 73(2):165–170 Winter JM, Cowie AI, Wood DJ, Zheng MH (2005) Musculoskeletal tissue banking in Western Australia: review of the first ten years. ANZ J Surg 75(8):665–671 Zwitser E, van Royen B (2011) Quality control in hospital bone banking. In: Wide Spectra of Quality Control, (Ed Akyar I) In Tech 14: 259–260. http://www.intechopen.com/books/ wide-spectra-of-quality-control/quality-control-in-hospitalbone-banking
ORIGINAL PAPER
The effectiveness of bone banking in Central Serbia: audit of the first seven years Zeljko Lj Stepanovic • Branko M Ristic
Received: 7 September 2013 / Accepted: 5 February 2014 Ó Springer Science+Business Media Dordrecht 2014
Abstract 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 Z. L. Stepanovic (&) B. M. Ristic Department of arthroplasty, Clinic for Orthopaedic and Trauma Surgery, Clinical Center Kragujevac, Zmaj Jovina 30, 34000 Kragujevac, Serbia e-mail: [email protected] Z. L. Stepanovic B. M. Ristic Faculty of Medical Science, University of Kragujevac, Svetozara Markovica 69, 34000 Kragujevac, Serbia
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. Keywords Bone banking Bone transplantation Femoral head allograft Allograft discarding Swab cultures Bacterial contamination
Introduction Many orthopaedic reconstructive procedures imply the frequent use of bone allografts. In most cases, these procedures are complex and time consuming. There is a potential risk for disease transmission if the bone allograft is contaminated (Tomford et al. 1990; Journeaux et al. 1999; Barnhart et al. 2009). Femoral head allografts retrieved at primary total hip arthroplasty (THA) are the most frequently used. Internal hospital bone banks are the most widely accepted source of supplying allogenic bone grafts. They are responsible for collecting, testing and storing of these allografts according to stringent protocols (Kappe et al. 2010). At donation, cultures are taken to exclude bacterial contamination of the femoral head, which is then stored in a fresh-frozen fashion from -70 °C to -80 °C. There are several methods used to obtain
123
Cell Tissue Bank
culture specimens, such as surface swab, joint swab, and bone or tissue biopsy. Between 1 and 22 % of the donated bone grafts are found to be contaminated and discarded. Most of the bone banks use swab cultures and bone biopsy immediately before implantation procedure, although there are no clinical evidence for their justification (Barnhart et al. 2009; Sommerville et al. 2000; James et al. 2004). It is mandatory for any bone bank to provide high quality measures to prevent contamination of bone allografts during retrieval and storing, particularly when sterilization procedures are not applied (Pruss et al. 2003). The bone bank unit at the Clinic for Orthopaedic and Trauma Surgery, Clinical Center Kragujevac, Central Serbia, was established in 2006. Its methods are based on the principles of the American Association of Tissue Banks (AATB 1992) and the European Association of Musculo-Skeletal Transplantation (EAMST 1997). This is the first audit of the institutional bone bank performance conducted over the past 7 years. The aim of the present study was to evaluate the quality system of bone banking and to ensure that we can provide high standard allografts with low infection rate.
Materials and methods Between January 2007 and May 2013, femoral head allografts were retrieved from a total of 295 patients aged between 36 and 90 years. Femoral heads were taken from those with fresh femoral neck fracture or after primary THA. Bone donation was voluntary and no financial or other benefits were granted. Informed consent was obtained, and a detailed history was taken to exclude malignancy, systemic and infectious diseases. Potential donors with severe degenerative changes or osteoporosis of femoral head were excluded from tissue procurment. The allografts are utilized to meet our own demands in orthopaedic and trauma procedures. The allografts were retrieved in the conventional orthopaedic theatre under aseptic conditions by ten orthopaedic surgeons. Furthermore, a prophylactic antibiotic (cefuroxime, 1.5 g or cefazoline 1.0 g) was given 30 min before surgery. The femoral head was released from soft tissues and two swab samples were taken by the main surgeon: one from the surgical site and the other one from the femoral head itself. After determining its size, the graft
123
was placed into a sterile plastic container by the surgeon. The container was sealed tightly, immediately isolated with two sterile separate bags, labeled and stored in a freezer at -70 °C within 30 min. Swab samples were sent to hospital laboratory for microbiological evaluation. Two cultures of aerobic and anaerobic microorganisms in blood agar, MacConkey agar, and chocolate blood agar were analyzed. The donors were tested for hepatitis B (HBs-antigen and anti HBc-antibodies) and C (HCV-antibodies and HCV-RNA), HIV (HIV1/2 antibodies) and syphilis (Treponema pallidum hemagglutination titre) at donation and at 6 months after surgery, according to the bone bank protocol. We always provide corresponding blood type grafts for recipients and Rh-compatible grafts to Rh-negative patients to prevent immunization (Meermans et al. 2007). All the blood test results at retrieval were documented in the donors’ bone bank records. These data are then filed in our bone bank inventory. A computerized record of each donor and recipient is also kept as a back-up system. These logs are regularly updated and checked by authorized bone bank personnel. We do not perform histopathological evaluation of femoral heads retrieved from living donors. The allografts that failed the selection criteria or were found to be contaminated have been discarded. Those that passed the screening tests were ready for use 6 months after admission. Bone allografts regarded acceptable are stored for a maximum of 5 years. Before application, the allograft is thawed in 500 ml of 0.9 % warm sterile saline with 1000 mg of amikacin. Intra-operative allograft cultures were not performed because there are no clinically relevant indicators that such culturing would assure any association between postoperative wound infection and positive intra-operative allograft cultures (Barnhart et al. 2009; Winter et al. 2005).
Results Over the past 7 years, we performed a total of 749 primary THA and 683 hemiarthroplasties. Due to strict selection criteria, only 11.85 % (81/683) of patients with fresh femoral neck fracture and 28.57 % (214/ 749) with hip osteoarthrosis met bone bank standards. Of the 295 retrieved femoral heads, 214 (72.54 %) were retrieved after primary THA and 81 (27.46 %) after femoral neck fracture. The bone allografts were
Cell Tissue Bank Table 1 Type and number of surgical procedures with fresh frozen femoral head allograft
Table 2 Organisms cultured from allograft bone retrieved (number of positive cultures)
Type of the procedure
Microorganism
Number of procedures
Coagulase-negative staphylococcus
Number of cultures 9 (24.32 %)
Revision total hip arthroplasty
36 (18.56 %)
Staphylococcus aureus
5 (13.51 %)
Primary total hip-and-knee arthroplasty
15 (7.73 %)
Staphylococcus epidermidis
6 (16.22 %)
Reconstructive surgery after failed fixation in trauma patients
50 (25.78 %)
Streptococcus viridans
2 (5.40 %)
Fixation of upper-limb fractures
13 (6.70 %)
Enterococcus faecalis
3 (8.11 %)
Fixation of lower-limb fractures
70 (36.08 %)
Gram-positive anaerobic cocci (GPAC)
5 (13.51 %)
Proteus mirabilis
2 (5.40 %)
Miscellaneous surgeries Total
10 (5.15 %) 194 (100 %)
retrieved from 110 men and 185 women. The mean age of donors after primary THA was 64 (36–80) years compared to 73 (45–90) years in donors with fractured femoral neck. A total of 194 (65.76 %) non-contaminated allografts were implanted by the end of the study (Table 1). The overall allograft discard rate was 26.1 %. The leading cause of allograft discarding was bacterial contamination. At retrieval, 37 allografts were positive for at least one micro-organism, giving an overall contamination rate of 12.54 %. The majority of these allografts were contaminated with bacteria commonly found on the skin (Table 2). Swab cultures of the surgical site were negative in all 37 donors. No surgical site infection was recorded in those patients during the mean follow-up period of 44 months (10–76). Seven (2.37 %) of the 295 allografts failed the blood screening tests and were thus discarded. One patient was false HIV positive, two were hepatitis C positive and four were with hepatitis B. Twelve allografts (4.06 %) were discarded because of suspected damage of the packaging or disuse during surgery. Due to death of the donor or inability to perform serology retests, 21 (7.11 %) allografts were discarded 180 days after admission. The remaining 28 allografts (9.49 %) are still stored in the bone bank. One hundred and ninety-four allografts were implanted to 180 recipients (maximum four allografts were used for one patient), of whom 69 were male and 111 were female. Mean age was 51 (18–86) years for male recipients and 68 (17–87) years for female population. Four out of 180 (2.22 %) patients developed deep postoperative wound infections. All infections occurred in trauma patients treated for distal
Acinetobacter species
2 (5.40 %)
Bacilus subtilis
1 (2.70 %)
Pseudomonas aeruginosa
1 (2.70 %)
Providencia species
1 (2.70 %)
Total
37 (100 %)
femoral fracture, tibial plateau fracture and two high energy calcaneal fractures. Staphylococcus species was isolated in three of four surgical site infections. In five recipients (2.77 %) the allograft incorporation was unsuccessful.
Discussion In the present study, we have reviewed the bone banking activities in the Clinical Center Kragujevac, Central Serbia, over the period of 7 years. There was a total of 295 (20.6 %) living donors among 1432 patients who were treated by hemiarthroplasty and primary THA. In other reports this ratio was between 15 and 60 % (Kappe et al. 2010; Phuong et al. 2013). According to donor selection criteria potential donors with severe degenerative changes or osteoporosis of femoral head were excluded from tissue harvesting. Therefore, there is no strong evidence that failures in allograft bone incorporation were attributed to poor quality of femoral heads retrieved from the bone bank. For this we accused accentuated immune response and poor vascularity of the host bone due to severe trauma and repetitive surgeries. In most reports, allograft discarding resulted from incidents at the time of its harvesting or from inabilities to perform the 6-month serology retests of donors (Winter et al. 2005; Hou and Yang 2005). The overall discard rate was 17–33 % in earlier reports (Hou and Yang 2005; Ivory and Thomas 1993; Nielsen
123
Cell Tissue Bank Table 3 Contamination rate in live donors
Retrieved allografts
Contaminated allografts
Study
Contamination rate (%)
Specimen
Used allografts
Serum postive allografts
Tomford et al. (1990)
11.8
Bone swab
70
Packaging failure
60
Journeaux et al. (1999)
13
Bone swab ? bone biopsy
Sommerville et al. (2000)
22
Bone swab ? joint swab ? bone biopsy
Sommerville et al. (2000)
12.9
Ivory and Thomas (1993)
1.2
Bone swab
Bone biopsy
Saies and Davidson (1990)
17
Joint swab ? bone biopsy
Chiu et al. (2004)
9.3
Bone biopsy
van de Pol et al. (2007)
6.4
Bone biopsy
et al. 2001). In evaluation performed by the Canadian Council for Donation and Transplantation, the average combined discard and deferral rate reported by large, well-established hospital bone banks was 49 % (CCDT 2006). In our series, the overall discard rate of 26 % was comparable with other hospital bone banks. The leading cause of allograft discarding was bacterial contamination. The germs most commonly identified in swab cultures at graft retrieval were Staphylococcus species which compared similarly with other studies (Journeaux et al. 1999; Vehmeyer et al. 2002; Deijkers et al. 1997). In this study, the contamination rate of allografts during harvest of the femoral heads was 12.54 %. Table 3 shows a comparison of rates in other reports. We used only swab culture to screen bacterial contamination of bone grafts. However, the swab culture had been proven inadequate to detect bacterial contamination of musculoskeletal allografts due to low sensitivity. It was found that the swab cultures after thawing were different from the wound cultures in most of the infected patients. It suggests that the allograft itself may not transmit the infection from donor to recipient (Hou and Yang 2005; Vehmeyer et al. 2002). Previous studies were unable to identify any association between positive intra-operative allograft cultures and the development of post-operative wound infection (Barnhart et al. 2009; Winter et al. 2005). The unacceptable 28.57 % (6/21) of contaminated femoral heads during the first year of harvesting was
123
50 40 30 20 10 0
2007
2008
2009
2010
2011
2012
2013
Fig. 1 The ratio between used and discarded allografts due to bacterial contamination, serum positive donors and packaging errors
due to problems with graft handling and inexperience (Fig. 1). Swab cultures and allograft handling was predominantly performed by scrub nurse. To avoid handling problem and responsibility, we decided that femoral heads should be swabbed and stored in container only by the main surgeon. We reduced the time between the osteotomy and storing of the allograft. We strived to exclude contact with allograft by using the reduction forceps. This measures resulted in reduction of bacterial contamination from 18.33 % in 2008 to 10.63 % in 2009 and 6.52 % in 2010. In next 2 years we recorded 17.64 and 5.17 % of contaminated bone allografts respectively. In the past 4 months of 2013 none of the femoral head allografts have been discarded from the bank. Evident reduction of contamination rate after the first year of the bone banking suggests that such problem can be prevented by strict adherence to quality measures, aseptic technique and careful allograft handling in the operating theatre. In the postoperative survey no obvious correlation was determined between infection and positive microbiological results of bone swab cultures. No infection was recorded in the postoperative follow-up among 37 donors whose femoral heads were discarded due to contamination. In recent report, no significant difference in the long-term outcome of total hip replacement in patients with or without femoral head contamination was found (Ibrahim et al. 2011). With prophylactic antibiotic administration before surgery, it is unlikely that bacteria of high virulence will hematogenously contaminate femoral heads. Femoral heads
Cell Tissue Bank
are contaminated either via air with skin flora from the operating room personnel and the environment (which was the scenario in our report) or per continuitatem with germs originating from skin of the donor. The entire surface of the femoral head can be sampled for culture swabs, although the contamination may not always be evenly spread over the allograft. Several studies doubt the cost effectiveness and necessity of routine histopathological examination. Tissue specimens can only be taken from a limited number of sites. It is therefore unlikely that tissue cultures would provide additional information (Vehmeyer et al. 2002). However, it is unclear whether the results after the use of multiple specimens reflect the true contamination rates (Zwitser and van Royen 2011). The AATB and the EAMST have excluded these tests in their standard screening protocol and currently we do not use them either (AATB 1992; EAMST 1997). Wound infection after bone allograft transplantation is a potentially devastating complication. It may lead to repetitive surgery, long-term antibiotic administration, poor patient outcome, and may have medicolegal implications. The use of sterilization techniques, antibiotics and histopathology is controversial. Attempts to achieve the perfect sterilization technique continue, but currently the safest method appears to be aseptic harvesting with strict monitoring (Meermans et al. 2007; Hou and Yang 2005; Deijkers et al. 1997). Fortunately, reported surgical site infection as a consequence of contaminated bone allograft is infrequent and ranges between 1.6 and 12 % (Kappe et al. 2010; Winter et al. 2005; Nielsen et al. 2001; Chiu et al. 2004; van de Pol et al. 2007; Sutherland et al. 1997). In our study, we recorded 2.22 % allograftrelated surgical site infections. The low infection rate and high allograft discard rate may indicate the effectiveness of the quality system monitoring in our institution. Recent studies issued the same conclusion that isolates grown from the culture after thawing were different from those isolated from the infected wound. The most of the recipients who received contaminated allografts were clinically with no sign of infection. This raises the question of justification of taking the swab and bone cultures after allograft thawing. Even positive swab cultures do not predict the development of infection in the recipient (Barnhart et al. 2009; Winter et al. 2005; Chiu et al. 2004). Our findings indicate that the highest risk of allograft contamination exists during its harvesting and thawing. Even
processed allograft may become contaminated during final application. Thus immersion of sterile allograft in saline solution with high doses of bactericidal antibiotics (such as amikacin) may act as secondary sterilization and prevent its superficial contamination. In conclusion, after 7 years of bone banking, our results show that overall discarding and infection rate after bone allotransplantation are in accordance with the international standards. The existing methods used in evaluation of bone allograft sterility are not sufficiently reliable. The leading cause of allograft discarding was bacterial contamination influenced by the surgical team. The contamination liability during bone allograft handling induced us to develop an optimal handling technique. We suggest stringent aseptic allograft handling during harvesting and thawing within highly concentrated antibiotic solution to reduce a possibility of its contamination.
References American Association of Tissue Banks (1992) Technical manual for tissue banking. AATB Barnhart B, Allan DG, Milbrandt JC, Khardori N, Hall A, Barenfanger J (2009). Intra-operative culturing of donor allograft bone: a lack of clinical utility. U Pa Orthop J. http://upoj.org/site/files/v19/v19_10.pdf Chiu CK, Lau PY et al (2004) Microbial contamination of femoral head allografts. Hong Kong Med J 10(6):401–405 Deijkers RLM, Bloem RM, Petit PLC, Brand R, Vehmeyer SBW, Veen MR (1997) Contamination of bone allografts: analysis of incidence and predisposing factors. J Bone Joint Surg (Br) 79(1):161–166 EAMST, EATB (1997) Common standards for musculo-skeletal tissue banking. European Association for Musculoskeletal Transplantation and European Association of Tissue Banks, Vienna Hou CH, Yang RS (2005) Hospital-based allogenic bone bank—10-year experience. J Hosp Infect 59:41–45 Ibrahim T, Aswad MG, Dias JJ, Brown AR, Esler CN (2011) Long-term outcome of total hip replacement in patients with or without femoral head contamination. J Orthop Surg (Hong Kong) 19(2):174–176 Ivory JP, Thomas IH (1993) Audit of a bone bank. J Bone Joint Surg Br 75:355–357 James LA, Ibrahim T, Esler CN (2004) Microbiological culture results for the femoral head. Are they important to the donor? J Bone Joint Surg Br 86(6):797–800 Journeaux SF, Johnson N, Bryce SL, Friedman SJ, Sommerville SM, Morgan DA (1999) Bacterial contamination rates during bone allograft retrieval. J Arthroplast 14(6):677–681 Kappe T, Cakir B, Mattes T, Reichel H, Flo¨ren M (2010) Infections after bone allograft surgery: a prospective study by a hospital bone bank using frozen femoral heads from living donors. Cell Tissue Bank 11:253–259
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Cell Tissue Bank Meermans G, Roos J, Hofkens L, Cheyns P (2007) Bone banking in a community hospital. Acta Orthop Belg 73:754–759 Nielsen HT, Larsen S, Andersen M, Ovesen O (2001) Bone bank service in Odense, Denmark. Audit first ten years with bone banking at the Department of Orthopaedics, Odense University Hospital. Cell Tissue Bank 2:179–183 Phuong DT, Park KS, Hwang SY, Lee DH, Yoon TR (2013) Microbiological culture findings of the femoral heads as a prognostic factor in the total hip replacement surgery. Clin Orthop Surg 5(2):105–109. doi:10.4055/cios.2013.5.2.105 Pruss A, Seibold M, Benedix F et al (2003) Validation of the ‘‘Marburg bone bank system’’ for thermodisinfection of allogenic femoral head transplants using selected bacteria, fungi, and spores. Biologicals 31(4):287–294 Saies AD, Davidson DC (1990) Femoral head allograft bone banking. Aust N Z J Surg 60:267–270 Sommerville SM, Johnson N, Bryce SL et al (2000) Contamination of banked femoral head allograft: incidence, bacteriology and donor follow up. Aust N Z J Surg 70(7):480–484 Sutherland AG, Raafat A, Yates P et al (1997) Infection associated with the use of allograft bone from the North East Scotland Bone Bank. J Hosp Infect 35:215–222
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The Canadian Council for Donation and Transplantation (CCDT) (2006) Evaluation of surgical bone banking and utilization in Canada. http://www.ccdt.ca. September 2006 Tomford WW, Thongphuasuk J, Mankin HJ, Ferraro MJ (1990) Frozen musculoskeletal allografts: a study of the clinical incidence and causes of infection associated with their use. J Bone Joint Surg (Am) 72(8):1137–1143 van de Pol GJ, Sturm PD, van Loon CJ, Verhagen C, Schreurs BW (2007) Microbiological cultures of allografts of the femoral head just before transplantation. J Bone Joint Surg Br 89(9):1225–1228 Vehmeyer SBW, Slooff RMA, Bloem RM, Petit PLC (2002) Bacterial contamination of femoral head allografts from living donors. Acta Orthop Scand 73(2):165–170 Winter JM, Cowie AI, Wood DJ, Zheng MH (2005) Musculoskeletal tissue banking in Western Australia: review of the first ten years. ANZ J Surg 75(8):665–671 Zwitser E, van Royen B (2011) Quality control in hospital bone banking. In: Wide Spectra of Quality Control, (Ed Akyar I) In Tech 14: 259–260. http://www.intechopen.com/books/ wide-spectra-of-quality-control/quality-control-in-hospitalbone-banking
