HIP
Cost analysis of fresh-frozen femoral head allografts IS IT WORTHWHILE TO RUN A BONE BANK? E. Benninger, P. O. Zingg, A.F. Kamath, C. Dora From Balgrist University Hospital, Department of Orthopaedics, University of Zurich, Zürich, Switzerland
To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed. From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking. Cite this article: Bone Joint J 2014;96-B:1307–11
E. Benninger, MD, Orthopaedic Surgeon P. O. Zingg, MD, Orthopaedic Surgeon C. Dora, MD, Orthopaedic Surgeon Balgrist University Hospital, Department of Orthopaedics, University of Zurich, Forchstrasse 340, 8008 Zürich, Switzerland. A.F. Kamath, MD, Orthopaedic Surgeon Pennsylvania Hospital, Department of Orthopaedic Surgery, 800 Spruce Street, Philadelphia, 19107, USA. Correspondence should be sent to Prof Dr Med C. Dora; e-mail: [email protected] ©2014 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.96B10. 33486 $2.00 Bone Joint J 2014;96-B:1307–11. Received 12 November 2013; Accepted after revision 28 May 2014
Bone grafting is widely used to fill bone defects and to enhance healing in orthopaedic trauma, tumour and reconstructive surgery. Autograft bone is used because of its osteoinductive, osteogenetic and osteoconductive properties.1-5 However, autograft has limited availability, and the associated donor morbidity with extended hospitalisation can increase the effective cost of harvesting to match the expense of purchasing commercially available bone graft substitutes.6-9 Allografts offer variable amounts of cortical or cancellous bone with osteoconductive but limited osteoinductive potential, but do afford good mechanical strength.10 Allograft can be provided as fresh-frozen and thawed at the time of surgery, or processed (i.e. freeze dried or irradiated). The mechanical properties of processed allograft are generally poorer than those of fresh-frozen allograft, as the processing may cause structural alterations.11-19 Both residual bone marrow cells and cells within fresh-frozen allograft carry an inherent risk of disease transmission. This has been reported in patients who experienced Human Immunodeficiency virus (HIV) and Hepatitis C virus transmission from non-processed bone allograft.20-22 In addition, there is a theoretical risk that the new variant Creutzfeldt Jakob disease (vCJD) could be transmitted via allograft bone. Due to these concerns, the European Union and the Swiss Federal Office of Public Health,
VOL. 96-B, No. 10, OCTOBER 2014
have issued directives to establish rigorous standards for tissue- banking facilities to minimise the risk of disease transmission.23,24 Quality standards also have to be met whenever any processing or storage of tissue takes place.23 Meeting these standards increases the price of allograft supplied by tissue banks. The costs associated with running an independent inhouse, fresh-frozen bone bank harvesting femoral heads from patients undergoing primary hip replacement (THR), need to be evaluated accordingly. The aim of this study was to evaluate the full cost of fresh-frozen femoral head allografts harvested and used within our institution from January 2007 to December 2010, and to compare this cost with that of commercially available processed allograft bone.
Materials and Methods All patients undergoing primary THR were invited to donate their redundant femoral head for use in reconstructive surgery. Their consent was required to enable harvesting. All patients who consented for bone donation and who had a normal C-reactive protein (CRP) (< 10 mg/L) and white blood cell count (WBC) (< 10 x 109 cells/L) underwent a donor-specific screening programme. This included a standard interview regarding medical history and potential exposure to transmissible diseases. 1307
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Table I. Calculated final costs per implanted femoral head allograft derived from the bone bank with all identifiable overheads included. CRP, c-reactive protein; WBC, white blood cells Price per unit (€) Fixed costs (total) Direct (total) Management manual Governmental approval Deep freezer (eight years amortisation time) Deep freezer (eight years amortisation time) Alarm installation (eight years amortisation time) Alarm installation (eight years amortisation time) Indirect (total) 10% work time secretary per year Energy consumption per year Maintenance and repair per year Variable costs (total) Direct (total) Screening per patient CRP WBC First serological test Second serological test Packing material per full or half FH Sterile box Sterile box Swab cultures per FH Indirect (total) Scrub nurse 20’ per full or half FH Physician 30’ per FH Total expenditure
Units
2940 1680 6090 6090 420 420
1 1 0.5 0.5 0.5 0.5
4032* 1210 571
4 4 4
Four-year expenditure (€) 34382 11130 2940 1680 3045 3045 210 210 23252 16128 4840 2284 159087 153143
8 8 237 237
290† 290† 290† 189‡
2320 2320 68730 44793
7 7 103
365§ 365§ 290†
8 16††
365¶ 189**
2555 2555 29870 5944 2920 3024 193469
Expenditure per allograft implanted (n = 141.5) 242
1124
1367
* 10% work time (half a day per week) for an administrative secretary; this administrative cost was independent of the number of femoral heads harvested and calculated to be € 4032 per year † Number of femoral heads harvested ‡ 101 femoral heads were withdrawn from the bone bank before the second serological screening was performed. § Boxes for 214 full and 151 half femoral heads ¶ The scrub nurse spent 20 minutes per harvested femoral head unit (full head or half head) to perform the storage process, for a cost of € 8 per harvest ** Release for the implanted 104 full femoral heads and 37.5 femoral heads stored in halves as well as for 42 full and 5.5 femoral heads stored in halves remaining within the bank †† The physician spent 30 minutes per harvested allograft bone to check all screening results and to sign for the release of the allograft. Based on his salary of € 98280 per year, a weekly work time of 60 hours 16 Euro were allocated for this activity per femoral allograft
Enquiries were made regarding a history of travelling from high risk regions, recently being tattooed or undergoing needling for acupuncture, and looking for any signs of acute or chronic local or systemic infection or malignant disease. In the event of any of these circumstances, the patient was excluded from donation. Those patients who passed the initial screening underwent an additional blood screening, which included testing for syphilis (ELISA), HIV (HIV-1 and HIV-2 antibodies and antigen), hepatitis B (hepatitis Bs antigen and Bc antibodies), and hepatitis C (hepatitis C antibodies and polymerase chain reaction). The blood samples for these tests were collected during surgery. Additionally, swabs from every harvested femoral head for microbiological culture were taken. Any positive blood test or microbiological culture excluded the patient from donation and the femoral head allograft was withdrawn from the bank. Femoral heads with diameters of < 56 mm were left in one piece (full/complete head), whereas large femoral
heads (> 56 mm in diameter) were bisected for storage. These grafts were double-packaged in two sterile boxes of 125 mL and 500 mL volume and stored at a constant temperature of -80° C in a deep freezer (Thermo Scientific Revco Freezer, model number ULT 1386-5-V41, Thermo Fisher Scientific, Inc., Reinach, Switzerland) with a temperature loss alarm (Thermomax SM Quattro, Kingspan Environmental Ltd, Co. Armagh, Northern Ireland) with constant monitoring by technical support staff of the hospital. A minimum of six months after femoral head harvesting, donors underwent a secondary screening, which consisted of the standardised questionnaire and a repeat blood testing for syphilis (ELISA), HIV (HIV-1 and HIV-2 antibodies and antigen), hepatitis B (hepatitis Bs antigen and Bc antibodies), and hepatitis C (hepatitis C antibodies and polymerase chain reaction). If any response or test was positive, the donated bone was withdrawn from the bank and the significance of the findings was discussed with the patient with THE BONE & JOINT JOURNAL
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Table II. Reasons for allograft femoral head donor exclusion Reason for exclusion
Description
Number of patients
Transmissable disease serologic findings
Hepatitis B (chronic/active) HIV Syphilis CRP (> 10mg/L) WBC count (> 10 x 109 cells/L) Positive swab culture Diagnosed neoplasm Risk for transmissable disease Missing data
21 1 1 26 11 6 3 22 20
Laboratory findings Culture findings (swab of bone) Positive questionnaire response Incomplete data set
CRP, C-reactive protein; WBC white blood cells Table III. Implanted femoral head allografts according to type and/or location of orthopaedic surgical procedure Implanted femoral head allografts (104 full heads; 75 half heads)
Number of recipients (n = 142)
Hip and pelvic surgery Spine surgery Foot and ankle surgery Tumour surgery Shoulder surgery Knee surgery Some patients received more than one allograft femoral head
76 35 12 11 6 2
an invitation to involve other agencies. A medical practitioner along with a secretary administered the bone bank, keeping records of supplementary investigations and treatment. Allograft bone was stored for a maximum of five years, and was for single-use, only within the institution. The medical records of all patients who had received fresh-frozen bone allograft from our bone bank were reviewed and all complications recorded. Particular attention was given to the development of a transmissible disease, but a routine blood screen was not undertaken. Under the terms of our institutional review board, additional retrospective analyses of patient data relating to standard diagnostic or therapeutic procedures, does not require individual informed consent. Over the four-year period, all costs associated with the management of the bone bank were calculated and divided by the amount of fresh-frozen femoral head allografts used. Whenever possible, overheads, which could be traced to the bone bank, were allocated to the direct and indirect variable and fixed costs (Table I). Other overheads, such as the space needed for the deep freezers, heating, cleaning and maintenance of the building, personal administration of people working for the bone bank part time were not taken into account since they were not estimated to relevantly increase the institution’s overheads and not quantifiable. Once we had established the total expenditure, including the investment involved in meeting the regulatory requirements, purchase of refrigerators and alarm systems, which contributed to the individual cost of our in-house femoral head allografts, we compared it with the price of commercially available allografts. As the investment costs were a constant, the individual cost of an in-house femoral head allograft depends on the number of such allografts used. Therefore, we undertook a breakeven analysis to determine VOL. 96-B, No. 10, OCTOBER 2014
the number of allografts at which costs per allograft matched the price of commercially purchased allografts. Only two brands of processed femoral head allografts are available in our country: Allobone (Neutromedics AG, CH6330 Cham, Switzerland) half and full femoral heads and Tutoplast (Novomedics GmbH, CH 8021 Zürich, Switzerland) half femoral heads. Both companies were asked for their current price list in order to make the comparison.
Results From January 2007 to December 2010, 290 femoral heads were harvested and stored either as full (214) or half (2 × 76) femoral heads. One femoral head was partially destroyed by osteoarthritis and provided only half a femoral head, resulting in 151 halves after bisection. During the process of screening, harvested bone from 101 patients (68 full and 65 half heads, which included the half head corresponding to the partially destroyed specimen) had to be withdrawn, resulting in 146 full and 86 half heads for future use. Some patients had more than one reason for withdrawal (Table II). Exclusion of these grafts may have been avoided in over one third of patients by improved donor triage management, as initial screening should have excluded them from an invitation to donate their bone. In total, 104 full femoral heads and 75 half femoral heads were implanted during this period; 42 full and 11 half femoral head allografts were not used and remained within the bank at the time of the study. The various applications of graft material according to orthopaedic procedure are shown in Table III. No clinical signs of allograft-related disease transmission were observed after a mean follow-up of 14 months (3 to 57; standard deviation (SD) 11). Post-operative complications occurred in 26 of 142 patients with 18 unrelated to
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graft use (four delayed wound healing, four superficial wound infection, four persistent deep hip infection with the same organism after two-stage revision, four hip dislocations, one post-operative haematoma, and one death due to general medical complications and metastatic disease) and with eight potentially related to the graft (four acetabular component aseptic loosening, three spinal fusion and one ankle nonunion). Cost analysis. Expenditures of bone banking from January 2007 to December 2010 are detailed in Table I. Costs for maintenance and repair were estimated at €571 per year (eight hours working time per year). Electricity consumption by the deep freezer units accounted for €1210 per year. Because managing the bone bank was a secondary task of an otherwise employed member of staff, no additional office space was required. Additional liability insurance was not required for running the bone bank, as responsibility was covered by the general insurance of the department. A total of €193 469 was expended and there were 141.5 femoral head allografts (104 full and 75 half) implanted during this time period. This results in €1367 (193469/ 141.5) expenditure or costs per used allograft. In total, €1124 of these €1367 are variable costs and will not change the unit price with varying volume. In contrast, €242 of these €1367 are fixed costs and will alter the unit price with volume: with an implanted volume of 63 femoral head allografts, the fixed cost per allograft would rise to €545 and provide a total cost of €1669 per allograft, which is similar to the price of €1672 for one femoral head allograft from Allobone; with an implanted volume of 34 femoral head allografts, fixed cost per allograft would raise to €1011 and result in €2135 per allograft, which is close to the price of €2149 for a femoral head from Tutoplast. At a price of €1 672 (Allobone) to €2149 (Tutoplast) for commercially purchased femoral head allografts, analysis of breakeven volume resulted in 34 to 63 femoral head allografts to be implanted within this four-year period.
Discussion Our in-house bone bank was cost-effective and has provided projected savings of at least €43 119 during a fouryear period. We found that more money could have been saved by more diligent application of the harvesting protocol. As a consequence of screening errors, unnecessary supplementary tests and harvesting undertaken, which inflated the costs of the successfully harvested and subsequently implanted allografts. The limitations of this study are that our findings may be unique to our institution and perhaps for our country. Differences in salaries, infrastructural costs, prices of commercially available processed allograft, as well as mandates from federal and state public health offices concerning standards for tissue banking, may differ from country to country and may influence the final product costs of freshfrozen allografting.25 In order to overcome this limitation, we detailed the individual costs as far as possible to simplify
translation of our model to other hospital and economic settings. We recognise it is not possible to determine every supplementary overhead related to the cost of the bone bank. However, as no extra personnel or buildings had to be acquired for the purpose of the bone bank, overheads arising from the bone bank to the hospital’s administration, maintenance or depreciation are not considered relevant to our calculations. In conclusion, our institution’s fresh-frozen allograft bone bank has proven to be economically viable. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by S. P. H. Hughes and first proof edited by G. Scott.
References 1. Bauer TW, Mutschler GF. Bone graft materials: an overview of the basic science. Clin Orthop Relat Res 2000;371:10–27. 2. Giannoudis PV. Fracture healing and bone regeneration: autologous bone grafting or BMP’s? Injury 2009;12:1243–1244. 3. Giannoudis PV, Kontakis G. Treatment of long bone aseptic non-unions: monotherapy or polytherapy? Injury 2009;40:1021–1022. 4. Sailhan F, Gleyzolle B, Parot R, Guerini H, Viguier E. Rh-BMP-2 in distraction osteogenesis: dose effect and premature consolidation. Injury 2010;41:680–686. 5. Desai PP, Bell AJ, Suk M. Treatment of recalcitrant, multiply operated tibial nonunions with the RIA graft and rh-BMP-2 using intramedullary nails. Injury 2010;2(Suppl):S69–S71. 6. Dahlin C, Johansson A. Iliac crest autogenous bone graft versus alloplastic graft and guided bone regeneration in the reconstruction of atrophic maxillae: a 5-year retrospective study on cost-effectiveness and clinical outcome. Clin Implant Dent Relat Res 2011;13:305–310. 7. Ahlmann E, Patzakis M, Roidis N, Sheperd L, Holtom P. Comparison of anterior and posterior iliac crest bone graft in terms of harvest-site morbidity and functional outcomes. J Bone Joint Surg [Am] 2002;84-A:716–720. 8. Younger EM, Chapman MW. Morbidity at bone graft donor sites. J Orthop Trauma 1989;3:192–195. 9. Summers BN, Eisenstein SM. Donor site pain from the ilium: a complication of lumbar spine fusion. J Bone Joint Surg [Br] 1989;71-B:677–680. 10. Habibovic P, de Groot K. Osteoinductive biomaterials: properties and relevance in bone repair. J Tissue Eng Regen Med 2007;1:25–32. 11. Kang JS, Kim NH. The biomechanical properties of deep freezing and freeze drying bones and their biomechanical changes after in-vivo allograft. Yonsei Med J 1995;36:332–335. 12. Nather A, Thambyah A, Goh J. Biomechanical strength of deep-frozen versus lyophilized large cortical allografts. Clin Biomech (Brisol, Avon) 2004;19:526–533. 13. Poitout D, Novakovitch G. Use of allografts in oncology and traumatology. Int Orthop 1987;11:169–178 (in French). 14. Simonian P, Conrad E, Chapman J, Harrington R, Chansky H. Effect of sterilisation and storage treatments on screw pullout strength in human allograft bone. Clin Orthop Relat Res 1994;302:290–296. 15. Anderson MJ, Keyak JH, Skinner HB. Compressive mechanical properties of human cancellous bone after gamma irradiation. J Bone Joint Surg [Am] 1992;74A:747–752. 16. Currey JD, Foreman J, Laketi? I, et al. Effects of ionizing radiation on the mechanical properties of human bone. J Orthop Res 1997;15:111–117. 17. Hamer A, Strachan J, Black M, et al. Biomechanical properties of cortical allograft bone using a new method of bone strength measurement: a comparison of fresh, fresh-frozen and irradiated bone. J Bone Joint Surg [Br] 1996;78-B:363–368. 18. Pelker RR, Friedlander GE, Markham TC. Biomechanical properties of bone allografts. Clin Orthop Relat Res 1983;174:54–57. 19. Vastel L, Masse C, Crozier E, et al. Effects of gamma irradiation on mechanical properties of defatted trabecular bone allografts assessed by speed-of-sound measurement. Cell Tissue Bank 2007;8:205–210. 20. Simonds RJ, Holmberg SD, Hurwitz RL, et al. Transmission of human immunodeficiency virus type 1 from a seronegative organ and tissue donor. N Engl J Med 1992;326:726–732. THE BONE & JOINT JOURNAL
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21. Simonds RJ. HIV transmission by organ and tissue transplantation. AIDS 1993;7(Suppl):S35–S38. 22. Conrad EU, Gretch DR, Obermeyer KR, et al. Transmission of the hepatitis-C virus by tissue transplantation. J Bone Joint Surg [Am] 1995;77-A:214–224. 23. No authors listed. Swiss Federal Act on the Transplantation of Organs, Tissues and Cells http://www.admin.ch (date last accessed 3 June 2014).
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24. No authors listed. European Parliament: Directive 2004/23/EC on setting standards of quality and safety for the donation, procurement, testing, processing, preservation, strorage and distribution of human tissue and cells. http://eur-lex.europa.eu/legalcontent/EN/TXT/?uri=CELEX:32004L0023 (date last accessed 07 August 2014.). 25. Jung S, Wernerus D, Reichel H. Approval of a bone bank: an institution’s experience. Orthopade 2012;41:217–224 (in German).
Cost analysis of fresh-frozen femoral head allografts IS IT WORTHWHILE TO RUN A BONE BANK? E. Benninger, P. O. Zingg, A.F. Kamath, C. Dora From Balgrist University Hospital, Department of Orthopaedics, University of Zurich, Zürich, Switzerland
To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed. From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking. Cite this article: Bone Joint J 2014;96-B:1307–11
E. Benninger, MD, Orthopaedic Surgeon P. O. Zingg, MD, Orthopaedic Surgeon C. Dora, MD, Orthopaedic Surgeon Balgrist University Hospital, Department of Orthopaedics, University of Zurich, Forchstrasse 340, 8008 Zürich, Switzerland. A.F. Kamath, MD, Orthopaedic Surgeon Pennsylvania Hospital, Department of Orthopaedic Surgery, 800 Spruce Street, Philadelphia, 19107, USA. Correspondence should be sent to Prof Dr Med C. Dora; e-mail: [email protected] ©2014 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.96B10. 33486 $2.00 Bone Joint J 2014;96-B:1307–11. Received 12 November 2013; Accepted after revision 28 May 2014
Bone grafting is widely used to fill bone defects and to enhance healing in orthopaedic trauma, tumour and reconstructive surgery. Autograft bone is used because of its osteoinductive, osteogenetic and osteoconductive properties.1-5 However, autograft has limited availability, and the associated donor morbidity with extended hospitalisation can increase the effective cost of harvesting to match the expense of purchasing commercially available bone graft substitutes.6-9 Allografts offer variable amounts of cortical or cancellous bone with osteoconductive but limited osteoinductive potential, but do afford good mechanical strength.10 Allograft can be provided as fresh-frozen and thawed at the time of surgery, or processed (i.e. freeze dried or irradiated). The mechanical properties of processed allograft are generally poorer than those of fresh-frozen allograft, as the processing may cause structural alterations.11-19 Both residual bone marrow cells and cells within fresh-frozen allograft carry an inherent risk of disease transmission. This has been reported in patients who experienced Human Immunodeficiency virus (HIV) and Hepatitis C virus transmission from non-processed bone allograft.20-22 In addition, there is a theoretical risk that the new variant Creutzfeldt Jakob disease (vCJD) could be transmitted via allograft bone. Due to these concerns, the European Union and the Swiss Federal Office of Public Health,
VOL. 96-B, No. 10, OCTOBER 2014
have issued directives to establish rigorous standards for tissue- banking facilities to minimise the risk of disease transmission.23,24 Quality standards also have to be met whenever any processing or storage of tissue takes place.23 Meeting these standards increases the price of allograft supplied by tissue banks. The costs associated with running an independent inhouse, fresh-frozen bone bank harvesting femoral heads from patients undergoing primary hip replacement (THR), need to be evaluated accordingly. The aim of this study was to evaluate the full cost of fresh-frozen femoral head allografts harvested and used within our institution from January 2007 to December 2010, and to compare this cost with that of commercially available processed allograft bone.
Materials and Methods All patients undergoing primary THR were invited to donate their redundant femoral head for use in reconstructive surgery. Their consent was required to enable harvesting. All patients who consented for bone donation and who had a normal C-reactive protein (CRP) (< 10 mg/L) and white blood cell count (WBC) (< 10 x 109 cells/L) underwent a donor-specific screening programme. This included a standard interview regarding medical history and potential exposure to transmissible diseases. 1307
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Table I. Calculated final costs per implanted femoral head allograft derived from the bone bank with all identifiable overheads included. CRP, c-reactive protein; WBC, white blood cells Price per unit (€) Fixed costs (total) Direct (total) Management manual Governmental approval Deep freezer (eight years amortisation time) Deep freezer (eight years amortisation time) Alarm installation (eight years amortisation time) Alarm installation (eight years amortisation time) Indirect (total) 10% work time secretary per year Energy consumption per year Maintenance and repair per year Variable costs (total) Direct (total) Screening per patient CRP WBC First serological test Second serological test Packing material per full or half FH Sterile box Sterile box Swab cultures per FH Indirect (total) Scrub nurse 20’ per full or half FH Physician 30’ per FH Total expenditure
Units
2940 1680 6090 6090 420 420
1 1 0.5 0.5 0.5 0.5
4032* 1210 571
4 4 4
Four-year expenditure (€) 34382 11130 2940 1680 3045 3045 210 210 23252 16128 4840 2284 159087 153143
8 8 237 237
290† 290† 290† 189‡
2320 2320 68730 44793
7 7 103
365§ 365§ 290†
8 16††
365¶ 189**
2555 2555 29870 5944 2920 3024 193469
Expenditure per allograft implanted (n = 141.5) 242
1124
1367
* 10% work time (half a day per week) for an administrative secretary; this administrative cost was independent of the number of femoral heads harvested and calculated to be € 4032 per year † Number of femoral heads harvested ‡ 101 femoral heads were withdrawn from the bone bank before the second serological screening was performed. § Boxes for 214 full and 151 half femoral heads ¶ The scrub nurse spent 20 minutes per harvested femoral head unit (full head or half head) to perform the storage process, for a cost of € 8 per harvest ** Release for the implanted 104 full femoral heads and 37.5 femoral heads stored in halves as well as for 42 full and 5.5 femoral heads stored in halves remaining within the bank †† The physician spent 30 minutes per harvested allograft bone to check all screening results and to sign for the release of the allograft. Based on his salary of € 98280 per year, a weekly work time of 60 hours 16 Euro were allocated for this activity per femoral allograft
Enquiries were made regarding a history of travelling from high risk regions, recently being tattooed or undergoing needling for acupuncture, and looking for any signs of acute or chronic local or systemic infection or malignant disease. In the event of any of these circumstances, the patient was excluded from donation. Those patients who passed the initial screening underwent an additional blood screening, which included testing for syphilis (ELISA), HIV (HIV-1 and HIV-2 antibodies and antigen), hepatitis B (hepatitis Bs antigen and Bc antibodies), and hepatitis C (hepatitis C antibodies and polymerase chain reaction). The blood samples for these tests were collected during surgery. Additionally, swabs from every harvested femoral head for microbiological culture were taken. Any positive blood test or microbiological culture excluded the patient from donation and the femoral head allograft was withdrawn from the bank. Femoral heads with diameters of < 56 mm were left in one piece (full/complete head), whereas large femoral
heads (> 56 mm in diameter) were bisected for storage. These grafts were double-packaged in two sterile boxes of 125 mL and 500 mL volume and stored at a constant temperature of -80° C in a deep freezer (Thermo Scientific Revco Freezer, model number ULT 1386-5-V41, Thermo Fisher Scientific, Inc., Reinach, Switzerland) with a temperature loss alarm (Thermomax SM Quattro, Kingspan Environmental Ltd, Co. Armagh, Northern Ireland) with constant monitoring by technical support staff of the hospital. A minimum of six months after femoral head harvesting, donors underwent a secondary screening, which consisted of the standardised questionnaire and a repeat blood testing for syphilis (ELISA), HIV (HIV-1 and HIV-2 antibodies and antigen), hepatitis B (hepatitis Bs antigen and Bc antibodies), and hepatitis C (hepatitis C antibodies and polymerase chain reaction). If any response or test was positive, the donated bone was withdrawn from the bank and the significance of the findings was discussed with the patient with THE BONE & JOINT JOURNAL
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Table II. Reasons for allograft femoral head donor exclusion Reason for exclusion
Description
Number of patients
Transmissable disease serologic findings
Hepatitis B (chronic/active) HIV Syphilis CRP (> 10mg/L) WBC count (> 10 x 109 cells/L) Positive swab culture Diagnosed neoplasm Risk for transmissable disease Missing data
21 1 1 26 11 6 3 22 20
Laboratory findings Culture findings (swab of bone) Positive questionnaire response Incomplete data set
CRP, C-reactive protein; WBC white blood cells Table III. Implanted femoral head allografts according to type and/or location of orthopaedic surgical procedure Implanted femoral head allografts (104 full heads; 75 half heads)
Number of recipients (n = 142)
Hip and pelvic surgery Spine surgery Foot and ankle surgery Tumour surgery Shoulder surgery Knee surgery Some patients received more than one allograft femoral head
76 35 12 11 6 2
an invitation to involve other agencies. A medical practitioner along with a secretary administered the bone bank, keeping records of supplementary investigations and treatment. Allograft bone was stored for a maximum of five years, and was for single-use, only within the institution. The medical records of all patients who had received fresh-frozen bone allograft from our bone bank were reviewed and all complications recorded. Particular attention was given to the development of a transmissible disease, but a routine blood screen was not undertaken. Under the terms of our institutional review board, additional retrospective analyses of patient data relating to standard diagnostic or therapeutic procedures, does not require individual informed consent. Over the four-year period, all costs associated with the management of the bone bank were calculated and divided by the amount of fresh-frozen femoral head allografts used. Whenever possible, overheads, which could be traced to the bone bank, were allocated to the direct and indirect variable and fixed costs (Table I). Other overheads, such as the space needed for the deep freezers, heating, cleaning and maintenance of the building, personal administration of people working for the bone bank part time were not taken into account since they were not estimated to relevantly increase the institution’s overheads and not quantifiable. Once we had established the total expenditure, including the investment involved in meeting the regulatory requirements, purchase of refrigerators and alarm systems, which contributed to the individual cost of our in-house femoral head allografts, we compared it with the price of commercially available allografts. As the investment costs were a constant, the individual cost of an in-house femoral head allograft depends on the number of such allografts used. Therefore, we undertook a breakeven analysis to determine VOL. 96-B, No. 10, OCTOBER 2014
the number of allografts at which costs per allograft matched the price of commercially purchased allografts. Only two brands of processed femoral head allografts are available in our country: Allobone (Neutromedics AG, CH6330 Cham, Switzerland) half and full femoral heads and Tutoplast (Novomedics GmbH, CH 8021 Zürich, Switzerland) half femoral heads. Both companies were asked for their current price list in order to make the comparison.
Results From January 2007 to December 2010, 290 femoral heads were harvested and stored either as full (214) or half (2 × 76) femoral heads. One femoral head was partially destroyed by osteoarthritis and provided only half a femoral head, resulting in 151 halves after bisection. During the process of screening, harvested bone from 101 patients (68 full and 65 half heads, which included the half head corresponding to the partially destroyed specimen) had to be withdrawn, resulting in 146 full and 86 half heads for future use. Some patients had more than one reason for withdrawal (Table II). Exclusion of these grafts may have been avoided in over one third of patients by improved donor triage management, as initial screening should have excluded them from an invitation to donate their bone. In total, 104 full femoral heads and 75 half femoral heads were implanted during this period; 42 full and 11 half femoral head allografts were not used and remained within the bank at the time of the study. The various applications of graft material according to orthopaedic procedure are shown in Table III. No clinical signs of allograft-related disease transmission were observed after a mean follow-up of 14 months (3 to 57; standard deviation (SD) 11). Post-operative complications occurred in 26 of 142 patients with 18 unrelated to
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E. BENNINGER, P. O. ZINGG, A.F. KAMATH, C. DORA
graft use (four delayed wound healing, four superficial wound infection, four persistent deep hip infection with the same organism after two-stage revision, four hip dislocations, one post-operative haematoma, and one death due to general medical complications and metastatic disease) and with eight potentially related to the graft (four acetabular component aseptic loosening, three spinal fusion and one ankle nonunion). Cost analysis. Expenditures of bone banking from January 2007 to December 2010 are detailed in Table I. Costs for maintenance and repair were estimated at €571 per year (eight hours working time per year). Electricity consumption by the deep freezer units accounted for €1210 per year. Because managing the bone bank was a secondary task of an otherwise employed member of staff, no additional office space was required. Additional liability insurance was not required for running the bone bank, as responsibility was covered by the general insurance of the department. A total of €193 469 was expended and there were 141.5 femoral head allografts (104 full and 75 half) implanted during this time period. This results in €1367 (193469/ 141.5) expenditure or costs per used allograft. In total, €1124 of these €1367 are variable costs and will not change the unit price with varying volume. In contrast, €242 of these €1367 are fixed costs and will alter the unit price with volume: with an implanted volume of 63 femoral head allografts, the fixed cost per allograft would rise to €545 and provide a total cost of €1669 per allograft, which is similar to the price of €1672 for one femoral head allograft from Allobone; with an implanted volume of 34 femoral head allografts, fixed cost per allograft would raise to €1011 and result in €2135 per allograft, which is close to the price of €2149 for a femoral head from Tutoplast. At a price of €1 672 (Allobone) to €2149 (Tutoplast) for commercially purchased femoral head allografts, analysis of breakeven volume resulted in 34 to 63 femoral head allografts to be implanted within this four-year period.
Discussion Our in-house bone bank was cost-effective and has provided projected savings of at least €43 119 during a fouryear period. We found that more money could have been saved by more diligent application of the harvesting protocol. As a consequence of screening errors, unnecessary supplementary tests and harvesting undertaken, which inflated the costs of the successfully harvested and subsequently implanted allografts. The limitations of this study are that our findings may be unique to our institution and perhaps for our country. Differences in salaries, infrastructural costs, prices of commercially available processed allograft, as well as mandates from federal and state public health offices concerning standards for tissue banking, may differ from country to country and may influence the final product costs of freshfrozen allografting.25 In order to overcome this limitation, we detailed the individual costs as far as possible to simplify
translation of our model to other hospital and economic settings. We recognise it is not possible to determine every supplementary overhead related to the cost of the bone bank. However, as no extra personnel or buildings had to be acquired for the purpose of the bone bank, overheads arising from the bone bank to the hospital’s administration, maintenance or depreciation are not considered relevant to our calculations. In conclusion, our institution’s fresh-frozen allograft bone bank has proven to be economically viable. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by S. P. H. Hughes and first proof edited by G. Scott.
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