Preliminary Report

Autobanking of femoral heads for revision total hip replacement, a preliminary report of a new surgical technique

Correspondence to: C.B. Hing, 42 Paramount Court, University Street, London, WC1E 6JP Email: CaroH2712@aol.com

Introduction Materials and methods Results

Discussion References

Keywords: Bone bank, femoral head, pouch
Surg J R Coll Surg Edinb Irel., 2 February 2004, 37-41

Background and Aim: Conventional banking of bone allografts has been well documented in the literature. It relies on standardised screening and providing a sterile storage facility. We report a new surgical technique of banking the femoral head in a surgically fashioned subperiosteal iliac pouch and its use for the donor’s own surgery. Material and Methods: Thirteen patients with an average age of 60 years and a diagnosis of osteoarthritis of the hip with a contralateral symptomatic loose hip replacement were selected. The femoral head was harvested and banked. On retrieval, histological analysis was performed in four specimens with clinical and radiographic review of all subjects. Results: Radiographic results show good integration of the morselised femoral head bone graft in revision hip surgery. Histological results from four retrieved specimens show viability at eight years and eleven months from insertion into the pouch. Discussion: Autobanking of the patient’s own femoral head is suitable in a select group of patients in whom a combined primary and contralateral revision total hip replacement poses an unacceptable anaesthetic risk. It has the advantage of providing a graft with osteoinductive potential and a reduced risk of infection. It eliminates the need for a storage facility and screening programme. It also provides a portable storage facility if the patient moves elsewhere

INTRODUCTION
Bone grafting is used extensively in orthopaedic reconstructive surgery. Autografts, allografts and xenografts have all been described in the literature.¹ Conventional bone banking of donated femoral heads for use in revision hip surgery relies on allograft donation, screening and storage.² However, for osteoinductive potential, fresh autograft remains the gold standard.³

We present a preliminary report on a new surgical technique for autobanking as a viable storage option for autograft and present the histological results of retrieved specimens from patients showing osteogenic potential at up to eight years and eleven months from initial storage.

MATERIALS AND METHODS
From 1992 to 2001, thirteen patients (six male and seven female) with an average age of 60 years, requiring a primary total hip replacement (THR) for osteoarthritis with a contralateral THR showing evidence of symptomatic loosening were selected for inclusion into the study and informed consent obtained. The femoral head was harvested at the time of primary hip replacement under sterile conditions. A skin incision over the iliac crest (on the side of primary hip surgery) allowed access to the pelvis. The periosteum was stripped from the inner surface of the iliac wing to fashion a pouch within the iliac fossa. The femoral head was divided in half and placed within this pouch, orientated with the cut surface closest to the iliac crest (Figure 1a, 1b). The soft tissues were repaired. Post-operative mobilisation was the same as for a conventional primary THR.

Revision surgery, in conjunction with harvesting of the banked femoral head, was performed at up to eight years eleven months from surgery in six patients. The patient was catheterised after administration of antibiotics and the iliac crest incision reopened. The femoral head was removed from the pelvis and samples taken for histology and microbiology for four of the specimens. The wound was closed with drainage. The femoral head was morselised and used as bone graft. The hip wound was reopened via an anterolateral approach. All components were removed. On the femoral side, mesh and impacted morselised bone graft were used as required to reconstruct any defects. A Charnley Elite cup and a long Charnley Elite stem were inserted with gentamicin Palacos cement. Recovery was uneventful with mobilisation on the fourth postoperative day. Post-operative radiographs show the revised femoral stem, morselised bone graft and mesh in situ (Figure 2).

RESULTS
Thirteen patients were followed up for up to nine years from the time of implantation. No morbidity was reported at the implantation site in the patients who underwent femoral head banking. In six patients the femoral head was harvested at eight months to eight years eleven months from implantation (Tables 1 and 2). Microbiological specimens taken from the femoral heads at the time of retrieval grew no organisms.  Histological examination of samples stained with haematoxylin and eosin taken at the time of retrieval of four of the femoral heads showed that small fragments of lamellar bone from the interface with the ilium were viable (Figure 3). Evidence of osteoid and remodelling indicated that the bone was viable, with both osteocytes and osteoblasts present indicating osteoinductive potential. The associated marrow showed focal haematopoietic activity and mild fibrosis. The articular cartilage was extensively necrotic and the underlying subchondral bone also exhibited necrosis. Tissue viability appeared to be dependent on the distance from the interface with the ilium. Thus, the region of the femoral head situated closest to the interface showed signs of osteoinductive potential, in contrast to the cartilage and underlying bone situated furthest from the interface with the ilium which showed evidence of necrosis. Tissue viability was also dependent on the the time from implantation, with some specimens exhibiting areas of creeping substitution.

Figure 1a: Intra-operative photograph showing fashioning of left iliac pouch and insertion of divided left femoral head 

Figure 1b: Post-operative radiograph showing right hybrid hip replacement, with evidence of loosening, left Charnley Elite hip replacement and left femoral head banked in left iliac fossa

DISCUSSION
Conventional bone banking has continued to develop since the first and oldest German Central Tissue Bank was established in 1956.⁵ It has been extensively reported in the literature and is subject to strict guidelines on donor selection, tissue harvesting, tissue storage and record keeping.⁴ Its disadvantages include risk of infection, which has been reported as 8-11% and risk of transmission of HIV, human T cell lymphotropic virus and the possibility of developing Rhesus antibodies.^2,5 Evidence of diseases such as chondrocalcinosis, avascular necrosis, osteomas and malignant tumours has been shown to exist in 3.6 - 8% of osteoarthritic femoral heads.^6,7 Deep freezing used for storing the majority of bone grafts at temperatures of less than -80°C has the disadvantage of incomplete inactivation of retroviruses and no bactericidal activities.

Sterilisation of banked bone to reduce the risk of infection has been reported using gamma irradiation.¹ However, whilst a dose of 15 000 - 25 000 gray is sufficient to ensure full sterilisation of bacteria, doses greater than 36 000 gray are necessary to inactivate all but one in a million HIV-infected cells. Undesirable consequences of high levels of radiation have been found to include alteration in mechanical properties and undesirable alteration of osteoinductive proteins. Ethylene oxide has also been proposed for sterilisation of bone graft but can only be used with small specimens due to limited penetration of the gas. Fatal allergic reactions to ethylene oxide have also been reported.¹

Autologous bone grafts are superior to allografts, both quantitatively and qualitatively, and remain the gold standard. Fresh autogenous bone graft has been previously employed for reconstructing a large segmental posterior column deficiency by bone banking the graft in the deficiency at the time of primary THR of the contralateral hip.⁸ The bone graft was found to be viable at the time of revision surgery and incorporated well with firm fixation of the revised acetabulum.

Figure 2: Post-operative radiograph following harvesting of left femoral head from iliac fossa pouch and revision of right hybrid hip replacement to right Charnley Elite hip replacement. Mesh and morselised bone graft from the left banked femoral head were used to reconstruct the defect present below the calcar.

Figure 3: Histological samples from a banked femoral head harvested at eight months from implantation in a 73 year old lady. Fragment of trabecular bone showing retention of osteocytes in most lacunae. Some osteoid covered by osteoblasts is present focally at the periphery. Strands of viable marrow are present at the periphery. [H&E stain, magnification x250.]

Autologous bone grafting, using the patient as a bone bank, has been reported in surgery for scoliosis.³ Rib fragments from adolescents or young children were stored in the paraspinal region for up to three weeks before being harvested and used as morselised bone grafts, posterior instrumentation and fusion. Histological examination showed more than 50% of osteocytes were viable but adjacent bone marrow had lost its basophilic staining and was not viable.

No previous case of autologous banking of a femoral head in a subperiosteal pouch has been reported in the literature. Our preliminary study shows that this is a viable option in a select group of patients with the advantage that the bone is still viable at eight years and eleven months from implantation. No morbidity was reported at the storage site. This technique has the potential advantage of providing a cheap and easy storage facility for autografts; this is portable if the patient moves to a different geographical location. It combines the biomechanical advantages of an autograft with the reduced risk of infection and malignant potential from allografts.

Whilst it is preferable to harvest a femoral head at the time of primary THR and use it for grafting on the contralateral side, a combined procedure may pose an unacceptable anaesthetic risk in the elderly and frail patient. In this instance banking the femoral head for later use is ideal. Disadvantages to this technique include the theoretical possibility of implanting a head with malignancy, causing spread of malignant cells and risks of morbidity at the iliac fossa pouch site such as ileus and damage to the lateral cutaneous nerve of the thigh. Also, in more complex revision cases (with larger defects), morselised bone from a single femoral head autograft may not be of sufficient volume to be used without an additional allograft or autograft which could be obtained from the iliac crest at the time of retrieval of the pouched femoral head, if necessary.

It is of interest that histological analysis at eight months from implantation has shown viable cells distributed in a distance-dependent fashion from the interface with the ilium. The longterm survival of osteoconductive and osteoinductive cells in the environment of an iliac fossa pouch, where no loading occurs on the femoral head, thus requires further histological investigation to determine the relationship of survival with distance from the interface with the ilium and with time from implantation. The potential for integration of the morselised femoral head bone graft following harvesting from the pouch site and its relationship to time from implantation also needs further investigation.

REFERENCES
1. Moreau MF, Gallois Y, Basle M-F, Chappard D. Gamma irradiation of human bone allografts alters medullary lipids and releases toxic compounds for osteoblastlike cells. Biomaterials 2000;21:369-376.
2. Ivory JP, Thomas IH. Audit of a bone bank. JBJS 1993;75B:3:355-357.
3. Chugh S, Marks DS, Mangham DC, Thompson AG. Autologous bone grafting in staged scoliosis surgery. The patient as a bone bank. Spine 1998;23:16:1793-1795.
4. American association of tissue banks. Technical manual for tissue banking. AATB,1992.
5. Aho AJ, Hirn M, Aro HT, Heikkila JT, Meurman O. Bone bank service in Finland. Experience of bacteriologic, serologic and clinical results of the Turku bone bank 1972-1995. Acta Orthop Scand 1998;69:6: 559-565.
6. Palmer SH, Gibbons CLM, Athanasou NA. The pathology of bone graft. JBJS 1999;81B:2:333-335.
7. Sugihara S, van Ginkel AD, Jiya TU, van Royen BJ, van Diest PJ, Wuisman PIJM. Histopathology of retrieved allografts of the femoral head. JBJS 1999;81B:2:336-341.
8. Oishi CS, Grady-Benson JC, Colwell CW. Autogenous bone banking in a contralateral total hip arthroplasty. A case report. The Journal of Arthroplasty 1995;10:1:109-112.

Copyright: 9 December 2003

Endocrine Surgery Masterclass

Royal College of Surgeons of Edinburgh and the British Association of Endocrine Surgeons

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