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Clinical experience with a new artificial bone graft: preliminary results of a prospective study
142
Injury
(1990)
21,142-144
Prind in GreatBritain
Clinical experience with a new artificial bone graft: preliminary results of a prospective study A. Kocialkowski’, W. Angus Wallace2 and H. G. Prince2 ‘Department of Traumatic Surgery, Medical Academy ‘Queen’s Medical Centre, Nottingham, UK
of Poznan, Poland
This prospectivestudy was car-rid out to determine the ejJicacy,benefits and safety of an artificial bone grafting material. The material usea’was a mikfure of porous calcium phosphate ceramic with the addition of bovine fibrillar collagen and au fogenousbone marrow. This mixture has been used suc~filly as a bone gaff in I I patients with delayed and non-union of long bones.
Introduction Fresh autogenous bone and frozen allografts (Kocialkowski et al., 1989a) are the most widely used materials for repairing bone defects. The need to minimize the quantity of autogenous bone for certain clinical cases has resulted in clinical trials of synthetically prepared and readily available osteoconductive ceramics. These ceramics are mainly composed of hydroxyapatite which is not reabsorbed in the body and tricalcium phosphate which is biodegradable (Jarcho, 1981). These two materials can be combined by a sintering process into a porous calcium phosphate ceramic, so tricalcium phosphate can resorb with time creating more space for bone ingrowth leaving hydroxyapatite to provide some structural strength in atrophic areas. Ceramic, commercially prepared as a porous block has several drawbacks. It is brittle, with a low impact and fracture resistance and, what is more important, the unnatural pathways of bone ingrowth provided by the pores result in retardation of bone healing and remodelling (Lane and Sandhu, 1987). In order to improve this, blocks of ceramic can be crushed into small granules which, when used, allow more space for bone to grow in. To obtain a uniform spread of granules within a defect the granules are suspended in a non-immunogenic bovine fibrillar collagen gel (Katthagen and Mittelmeier, 1984) and bone marrow is added which will provide an osteogenic stimulus (Kocialkowski et al., 1990a).
Previous experimental investigation In order to identify the best ceramic:collagen ratio when mixed with bone marrow for new bone formation and to clarify the optimal and minimum acceptable ratios of bone marrow, several animal heterotopic studies have been carried out (Kocialkowski et al., 199Oa; Kocialkowski et al., 199Ob). We have shown that collagen and porous granular 0 1990 Butterworth-Heinema 0020-1383/90/030142-03
Ltd
ceramic alone lacks osteogenic capacity; however, when used in a composite graft with autologous red marrow there is heterotopic bone formation within the confines of the ceramic/collagen mixture. The new bone formation is directly proportional to the bone marrow volume used and the optimal bone marrow volume for heterotopic bone formation is between 40 and 60 per cent. We also confirmed that heterotopic bone formation is inversely proportional to the ceramic volume ratio, so the less ceramic that is used the more bone is formed with the optimal ceramic volume ratio between 33 and 25 per cent. As ceramic/collagen bone grafts have in the past been studied mainly in fresh cancellous bone and cortical bleeding defects (Grundel et al., 1987) we have conducted animal non-union orthotopic studies (Kocialkowski et al., 1989b) to clarify whether the ceramic/collagenlmarrow mixture is effective in a nonunion and if additional bone marrow is necessary. Cancellous bone graft was found to be more effective in healing experimental non-union than a mixture of ceramic, collagen and 20 per cent bone marrow. We confirmed that addition of 20 per cent bone marrow to the osteoconductive ceramic/ collagen mixture is not an efficient osteogenic stimulus and that the addition of larger volumes of bone marrow (around 60 per cent) was necessary. Histology of the local tissues (F@re I) confirmed that bone-ceramic interfaces did not show inflammatory interfaces and in all instances the ceramic was biocompatible.
Materials and methods Porous calcium phosphate ceramic mixed with fibrillar collagen, is currently undergoing investigation as a bone substitute (Collagraft@Y. The fibrillar collagen is highly purified collagen obtained from bovine dermis, supplied in a gel form and contained in a syringe. The ceramic is a biphasic formulation of 65 per cent hydroxyapatite and 35 per cent tricalcium phosphate in a granular form 0.5-1.0 mm in diameter). At the time of surgery the collagen and ceramic are thoroughly mixed in a bowl and autologous bone marrow (aspirated from an iliac crest) is added in a ratio of
*C&graft@ is manufactured Collagen
Corporation,
by Zimmer Inc., Warsaw, Palo Alto, California.
Indiana
and
143
Kocialkowski et al.: New artificial bone graft
mixture varying in volume from 15 to 25 CC. Although autogenous bone marrow was included in the above mixture no supplemental autogenous bone graft was used in any of the eleven cases. The follow-up assessment was performed postoperatively, at week 6, and months 3,6 and 12. It included two radiographs of the graft site at each visit, a physical examination, a clinical assessment of postoperative pain and an assessment of wound healing and any signs of inflammation.
Results The follow-up period ranged from 25 to 132 weeks, with an average of 58.7 weeks. Fracture union was achieved in all cases. The follow-up radiographs of one grafted high tibia1 osteotomy non-union (Figttre 2), one grafted delayed union of proximal femur (Figure 3) and one grafted delayed union of mid-shaft humerus (Figure4) are shown, Fracture union was based on the radiographic disappearance of the fracture line. No adverse short-term reactions such as wound drainage, erythema and inflammation, or long-term graft site complications, such as infection, refracture, resorption and loss of fixation were seen. Laboratory haematology and biochemistry tests performed in all patients 6 months after grafting did not show any abnormality.
Figure 1. Good incorporation of granular ceramic into the bone
(resin embedded section, toluidine blue, x
40). a,
Ceramic. b, Bone.
5 ml of bone marrow to 7 ml of PUFC (more than 50 per cent of bone marrow by volume). To be eligible for the study, patients had to have a delayed or non-union of a long bone (or a failed arthrodesis), be aged between 18 and 70 years and be in good general health. Patients with a recent history of osteomyelitis, malignancy, metabolic bone disease and those using corticosteroids or immunosuppressive agents were excluded. Eleven patients have been implanted with the ceramic/collagen/marrow mixture (If& I). All presented with demonstrable delayed or non-union with osseous defects necessitating bone grafting. Nine men and two women were included in the study, with an average age of 46.2 years (range 23-70 years). Operations were performed an average of 29 weeks after injury (range lo-65 weeks). The location of the defect was re-arthrodesis of a knee in two (at 65 weeks and 52 weeks), a delayed union of a mid-shaft radius fracture in one (at 21 weeks), a delayed union of a very mobile mid-shaft of humerus fracture in one (at 12 weeks), a humeral mid-shaft non-union in one case (at 52 weeks), a distal femoral fractur4elayed union in one (at 32 weeks), a proximal third femoral delayed union in three (two at 12 weeks and one at 10 weeks), a segmental delayed union of a tibia1 fracture in one case (at I 7 weeks) and a high tibia1 osteotomy non-union in one case (at 33 weeks). Following reduction, internal fixation was performed using an AO-nail in two, an external fixator in one, a dynamic hip screw with a x2-hole plate in three, a buttress L-plate in one, a dynamic condylar screw with 12-hole plate in one, and a dynamic compression plate in three cases. The resulting bone defect was filled with a ceramic/collagen/marrow
Table I. Clinical details of the 11 patients implanted
Patient A0 KD VK AR IH TD RW JW JW IS MO
Sex
Age
Sire of grafting
M M F M M M M M M M F
50 26 38 50 60 52 62 23 70 25 52
Humerus mid-shaft Humerus mid-shaft Femur proximal Tibia proximal Femur distal Radius mid-shaft Tibia mid-shaft Knee re-arthrodesis Femur proximal Knee re-arthrodesis
Femur proximal
Discussion This study has shown that this artificial bone grafting material (ceramic/collagen/marrow) is effective in promoting the union of bones. The major difficulty with this grafting material in its current gel/granular formulation was in its application to the fracture site. When filling the fracture site with the ceramic/collagen/marrow mixture, the mixture occasionally became very liquid as it absorbed any remain-
Figure grafted weeks weeks
2. The follow-up radiographs of a high tibia1 osteotomy with ceramic/collagen/marrow mixture. a, Non-union (33 since operation). b, Day one after grafting. c, United 37 after grafting.
with the ceramic/collagen/marrow
mixture
Time from injury (weeks)
State of union
12 52 12 12 33 32 21 17 65 10 52
Delayed union Non-union Delayed union Delayed union Non-union Delayed union Delayed union Delayed union Non-union Delayed union Non-union
Implant 12 hole DHS 4.5 mm DCP 4.5 mm DCP 12 Hole OHS L Plate DCS 3.5 mm DCP External fixation A0 17 mm nail 12 Hole DHS A0 17 mm nail
Follow-up (weeks) 25 25 52 76 37 80 60 78 52 29 132
the British Journal of Accident Surgery (1990)Vol. Zl/No. Injury:
144
3
which allows bone marrow to clot and improve the viscosity of this mixture. 3. The volume of added bone marrow should be around 50 per cent of the total volume of grafted ceramic/ collagen matrix. 4. The graft site should be closed very carefully with soft
tissue sutures as they are the only barrier to prevent the mixture flowing out from the graft site. Despite the apptication problems, these reported results in II patients are encouraging. The need to minimize the quantity of autogenous bone for certain clinical cases justifies further trials on this form of artificial bone graft. However, more patients and a longer follow-up period will be necessary to establish the safety and full efficacy of this artificial bone grafting material. Figure 3. The follow-up
radiographs
of a delayed
proximal femur grafted with ceramic/collagen/marrow
union of a mixture. a,
Delayed union (12 weeks on traction). b, Day one after grafting and plating. c, United 76 weeks after grafting.
Figure4 The follow-up radiographs of a delayed union of a mid-shaft humerus grafted with ceramic/collagen/marrow mixture. a, Delayed union (12 weeks since fracture), b, Day one after DCP plating and grafting. c, United 52 weeks after grafting.
ing blood and started to flow out. As a result, the spoon filling technique was found to be inadequate as it was difficult to fill the bone defect thoroughly. The further escape of mixture was stopped by carefully suturing the soft tissues. As a result of this study the following recommendations for the use of ceramic/collagen/marrow in the gel/granular formulation can be made: the ceramic/collagen/marrow mixture the graft site should be as dry as possible and bleeding should be controlled with cautery and by using hydrogen peroxide. 2. Mixing of ceramic/collagen matrix with bone marrow should be performed at least 20 min before grafting
References Grundel R. E., Chapman M. W. and Yet T. (1987) Evaluation of type I collagen and a biphasic ceramic in diaphyseal defects of the ulna and metaphyseal defects of the humerus in the canine. Transactions of the ~3rd Annual Meeting of the Orthopaedic Research Society, 19. Jarcho M. (1981) Calcium phosphate ceramics as hard tissue prosthetics. Clin. orthop. 157, 259. Katthagen B. D. and Mittelmeier H. (1984) Experimental animal investigation of bone regeneration with Collagen-Apatite. Arch. Orthop. Trauma Surg. 103, 291. Kocialkowski A., Wallace W. A. and Prince H. G. (1989a) The use of frozen cadaveric allografts in Nottingham. Transactions of the British Association of Clinical Anatomists, January 1989. Chin. Anal. 2, 123. Kocialkowski A., Wallace W. A. But-well R. G. et al. (1989b) Cancellous bone versus ceramic/collagen/marrow mixture in an experimental non-union. In: Transactions of the British Orthopaedic Research Society Meeting, Imperial College London, Sept. 12. Kocialkowski A., Wallace W. A., Burwell R. G. et al. (1990a) Collagen and ceramic as an osteoconductive matrix for heterotopic bone formation. In: Transactions of the British Orthopaedie Research Society Meeting, March 1989,J Bone Joint Surg. 7213,163. Kocialkowski A., Wallace W. A. and Burwell R. G. (199Ob) Bone marrow and granular ceramic contributions to bone formation. In: Transactions of the British Association of Clinical Anatomists July 1989, Chn. Anat. 3, 65. Lane J. M. and Sandhu H. S. (1987) Current approaches to experimental bone grafting. Orthop. Clin. North Am. 18, 213.
Paper accepted
17 November
1989.
1. Before using
&quesfs for reprints should be addressed to: Professor W. A. Wallace, Department of Orthopaedic and Accident Surgery, University of Nottingham, Queen’s Medical Centre, Nottingham NG7 XJH, UK.
Injury
(1990)
21,142-144
Prind in GreatBritain
Clinical experience with a new artificial bone graft: preliminary results of a prospective study A. Kocialkowski’, W. Angus Wallace2 and H. G. Prince2 ‘Department of Traumatic Surgery, Medical Academy ‘Queen’s Medical Centre, Nottingham, UK
of Poznan, Poland
This prospectivestudy was car-rid out to determine the ejJicacy,benefits and safety of an artificial bone grafting material. The material usea’was a mikfure of porous calcium phosphate ceramic with the addition of bovine fibrillar collagen and au fogenousbone marrow. This mixture has been used suc~filly as a bone gaff in I I patients with delayed and non-union of long bones.
Introduction Fresh autogenous bone and frozen allografts (Kocialkowski et al., 1989a) are the most widely used materials for repairing bone defects. The need to minimize the quantity of autogenous bone for certain clinical cases has resulted in clinical trials of synthetically prepared and readily available osteoconductive ceramics. These ceramics are mainly composed of hydroxyapatite which is not reabsorbed in the body and tricalcium phosphate which is biodegradable (Jarcho, 1981). These two materials can be combined by a sintering process into a porous calcium phosphate ceramic, so tricalcium phosphate can resorb with time creating more space for bone ingrowth leaving hydroxyapatite to provide some structural strength in atrophic areas. Ceramic, commercially prepared as a porous block has several drawbacks. It is brittle, with a low impact and fracture resistance and, what is more important, the unnatural pathways of bone ingrowth provided by the pores result in retardation of bone healing and remodelling (Lane and Sandhu, 1987). In order to improve this, blocks of ceramic can be crushed into small granules which, when used, allow more space for bone to grow in. To obtain a uniform spread of granules within a defect the granules are suspended in a non-immunogenic bovine fibrillar collagen gel (Katthagen and Mittelmeier, 1984) and bone marrow is added which will provide an osteogenic stimulus (Kocialkowski et al., 1990a).
Previous experimental investigation In order to identify the best ceramic:collagen ratio when mixed with bone marrow for new bone formation and to clarify the optimal and minimum acceptable ratios of bone marrow, several animal heterotopic studies have been carried out (Kocialkowski et al., 199Oa; Kocialkowski et al., 199Ob). We have shown that collagen and porous granular 0 1990 Butterworth-Heinema 0020-1383/90/030142-03
Ltd
ceramic alone lacks osteogenic capacity; however, when used in a composite graft with autologous red marrow there is heterotopic bone formation within the confines of the ceramic/collagen mixture. The new bone formation is directly proportional to the bone marrow volume used and the optimal bone marrow volume for heterotopic bone formation is between 40 and 60 per cent. We also confirmed that heterotopic bone formation is inversely proportional to the ceramic volume ratio, so the less ceramic that is used the more bone is formed with the optimal ceramic volume ratio between 33 and 25 per cent. As ceramic/collagen bone grafts have in the past been studied mainly in fresh cancellous bone and cortical bleeding defects (Grundel et al., 1987) we have conducted animal non-union orthotopic studies (Kocialkowski et al., 1989b) to clarify whether the ceramic/collagenlmarrow mixture is effective in a nonunion and if additional bone marrow is necessary. Cancellous bone graft was found to be more effective in healing experimental non-union than a mixture of ceramic, collagen and 20 per cent bone marrow. We confirmed that addition of 20 per cent bone marrow to the osteoconductive ceramic/ collagen mixture is not an efficient osteogenic stimulus and that the addition of larger volumes of bone marrow (around 60 per cent) was necessary. Histology of the local tissues (F@re I) confirmed that bone-ceramic interfaces did not show inflammatory interfaces and in all instances the ceramic was biocompatible.
Materials and methods Porous calcium phosphate ceramic mixed with fibrillar collagen, is currently undergoing investigation as a bone substitute (Collagraft@Y. The fibrillar collagen is highly purified collagen obtained from bovine dermis, supplied in a gel form and contained in a syringe. The ceramic is a biphasic formulation of 65 per cent hydroxyapatite and 35 per cent tricalcium phosphate in a granular form 0.5-1.0 mm in diameter). At the time of surgery the collagen and ceramic are thoroughly mixed in a bowl and autologous bone marrow (aspirated from an iliac crest) is added in a ratio of
*C&graft@ is manufactured Collagen
Corporation,
by Zimmer Inc., Warsaw, Palo Alto, California.
Indiana
and
143
Kocialkowski et al.: New artificial bone graft
mixture varying in volume from 15 to 25 CC. Although autogenous bone marrow was included in the above mixture no supplemental autogenous bone graft was used in any of the eleven cases. The follow-up assessment was performed postoperatively, at week 6, and months 3,6 and 12. It included two radiographs of the graft site at each visit, a physical examination, a clinical assessment of postoperative pain and an assessment of wound healing and any signs of inflammation.
Results The follow-up period ranged from 25 to 132 weeks, with an average of 58.7 weeks. Fracture union was achieved in all cases. The follow-up radiographs of one grafted high tibia1 osteotomy non-union (Figttre 2), one grafted delayed union of proximal femur (Figure 3) and one grafted delayed union of mid-shaft humerus (Figure4) are shown, Fracture union was based on the radiographic disappearance of the fracture line. No adverse short-term reactions such as wound drainage, erythema and inflammation, or long-term graft site complications, such as infection, refracture, resorption and loss of fixation were seen. Laboratory haematology and biochemistry tests performed in all patients 6 months after grafting did not show any abnormality.
Figure 1. Good incorporation of granular ceramic into the bone
(resin embedded section, toluidine blue, x
40). a,
Ceramic. b, Bone.
5 ml of bone marrow to 7 ml of PUFC (more than 50 per cent of bone marrow by volume). To be eligible for the study, patients had to have a delayed or non-union of a long bone (or a failed arthrodesis), be aged between 18 and 70 years and be in good general health. Patients with a recent history of osteomyelitis, malignancy, metabolic bone disease and those using corticosteroids or immunosuppressive agents were excluded. Eleven patients have been implanted with the ceramic/collagen/marrow mixture (If& I). All presented with demonstrable delayed or non-union with osseous defects necessitating bone grafting. Nine men and two women were included in the study, with an average age of 46.2 years (range 23-70 years). Operations were performed an average of 29 weeks after injury (range lo-65 weeks). The location of the defect was re-arthrodesis of a knee in two (at 65 weeks and 52 weeks), a delayed union of a mid-shaft radius fracture in one (at 21 weeks), a delayed union of a very mobile mid-shaft of humerus fracture in one (at 12 weeks), a humeral mid-shaft non-union in one case (at 52 weeks), a distal femoral fractur4elayed union in one (at 32 weeks), a proximal third femoral delayed union in three (two at 12 weeks and one at 10 weeks), a segmental delayed union of a tibia1 fracture in one case (at I 7 weeks) and a high tibia1 osteotomy non-union in one case (at 33 weeks). Following reduction, internal fixation was performed using an AO-nail in two, an external fixator in one, a dynamic hip screw with a x2-hole plate in three, a buttress L-plate in one, a dynamic condylar screw with 12-hole plate in one, and a dynamic compression plate in three cases. The resulting bone defect was filled with a ceramic/collagen/marrow
Table I. Clinical details of the 11 patients implanted
Patient A0 KD VK AR IH TD RW JW JW IS MO
Sex
Age
Sire of grafting
M M F M M M M M M M F
50 26 38 50 60 52 62 23 70 25 52
Humerus mid-shaft Humerus mid-shaft Femur proximal Tibia proximal Femur distal Radius mid-shaft Tibia mid-shaft Knee re-arthrodesis Femur proximal Knee re-arthrodesis
Femur proximal
Discussion This study has shown that this artificial bone grafting material (ceramic/collagen/marrow) is effective in promoting the union of bones. The major difficulty with this grafting material in its current gel/granular formulation was in its application to the fracture site. When filling the fracture site with the ceramic/collagen/marrow mixture, the mixture occasionally became very liquid as it absorbed any remain-
Figure grafted weeks weeks
2. The follow-up radiographs of a high tibia1 osteotomy with ceramic/collagen/marrow mixture. a, Non-union (33 since operation). b, Day one after grafting. c, United 37 after grafting.
with the ceramic/collagen/marrow
mixture
Time from injury (weeks)
State of union
12 52 12 12 33 32 21 17 65 10 52
Delayed union Non-union Delayed union Delayed union Non-union Delayed union Delayed union Delayed union Non-union Delayed union Non-union
Implant 12 hole DHS 4.5 mm DCP 4.5 mm DCP 12 Hole OHS L Plate DCS 3.5 mm DCP External fixation A0 17 mm nail 12 Hole DHS A0 17 mm nail
Follow-up (weeks) 25 25 52 76 37 80 60 78 52 29 132
the British Journal of Accident Surgery (1990)Vol. Zl/No. Injury:
144
3
which allows bone marrow to clot and improve the viscosity of this mixture. 3. The volume of added bone marrow should be around 50 per cent of the total volume of grafted ceramic/ collagen matrix. 4. The graft site should be closed very carefully with soft
tissue sutures as they are the only barrier to prevent the mixture flowing out from the graft site. Despite the apptication problems, these reported results in II patients are encouraging. The need to minimize the quantity of autogenous bone for certain clinical cases justifies further trials on this form of artificial bone graft. However, more patients and a longer follow-up period will be necessary to establish the safety and full efficacy of this artificial bone grafting material. Figure 3. The follow-up
radiographs
of a delayed
proximal femur grafted with ceramic/collagen/marrow
union of a mixture. a,
Delayed union (12 weeks on traction). b, Day one after grafting and plating. c, United 76 weeks after grafting.
Figure4 The follow-up radiographs of a delayed union of a mid-shaft humerus grafted with ceramic/collagen/marrow mixture. a, Delayed union (12 weeks since fracture), b, Day one after DCP plating and grafting. c, United 52 weeks after grafting.
ing blood and started to flow out. As a result, the spoon filling technique was found to be inadequate as it was difficult to fill the bone defect thoroughly. The further escape of mixture was stopped by carefully suturing the soft tissues. As a result of this study the following recommendations for the use of ceramic/collagen/marrow in the gel/granular formulation can be made: the ceramic/collagen/marrow mixture the graft site should be as dry as possible and bleeding should be controlled with cautery and by using hydrogen peroxide. 2. Mixing of ceramic/collagen matrix with bone marrow should be performed at least 20 min before grafting
References Grundel R. E., Chapman M. W. and Yet T. (1987) Evaluation of type I collagen and a biphasic ceramic in diaphyseal defects of the ulna and metaphyseal defects of the humerus in the canine. Transactions of the ~3rd Annual Meeting of the Orthopaedic Research Society, 19. Jarcho M. (1981) Calcium phosphate ceramics as hard tissue prosthetics. Clin. orthop. 157, 259. Katthagen B. D. and Mittelmeier H. (1984) Experimental animal investigation of bone regeneration with Collagen-Apatite. Arch. Orthop. Trauma Surg. 103, 291. Kocialkowski A., Wallace W. A. and Prince H. G. (1989a) The use of frozen cadaveric allografts in Nottingham. Transactions of the British Association of Clinical Anatomists, January 1989. Chin. Anal. 2, 123. Kocialkowski A., Wallace W. A. But-well R. G. et al. (1989b) Cancellous bone versus ceramic/collagen/marrow mixture in an experimental non-union. In: Transactions of the British Orthopaedic Research Society Meeting, Imperial College London, Sept. 12. Kocialkowski A., Wallace W. A., Burwell R. G. et al. (1990a) Collagen and ceramic as an osteoconductive matrix for heterotopic bone formation. In: Transactions of the British Orthopaedie Research Society Meeting, March 1989,J Bone Joint Surg. 7213,163. Kocialkowski A., Wallace W. A. and Burwell R. G. (199Ob) Bone marrow and granular ceramic contributions to bone formation. In: Transactions of the British Association of Clinical Anatomists July 1989, Chn. Anat. 3, 65. Lane J. M. and Sandhu H. S. (1987) Current approaches to experimental bone grafting. Orthop. Clin. North Am. 18, 213.
Paper accepted
17 November
1989.
1. Before using
&quesfs for reprints should be addressed to: Professor W. A. Wallace, Department of Orthopaedic and Accident Surgery, University of Nottingham, Queen’s Medical Centre, Nottingham NG7 XJH, UK.