- Email: [email protected]
Calcium phosphate cement to prevent collapse in avascular necrosis of the femoral head
Medical Hypotheses 74 (2010) 725–726
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Calcium phosphate cement to prevent collapse in avascular necrosis of the femoral head Vincent Y. Ng, Jeffrey F. Granger, Thomas J. Ellis * Department of Orthopaedics, The Ohio State University Medical Center, 2050 Kenny Road, Columbus, OH 43221, United States
a r t i c l e
i n f o
Article history: Received 21 October 2009 Accepted 26 October 2009
s u m m a r y Subchondral and articular collapse following nontraumatic osteonecrosis of the femoral head is an important cause of osteoarthritis in patients between ages 20 and 40. Because hip arthroplasty in the younger population is prone to early wear and failure, it is paramount to prevent collapse once osteonecrosis is detected. Natural remodeling of the osteonecrotic areas by adjacent normal bone is predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place. Current treatment modalities include core decompression and various adjuncts such as bone graft, mesenchymal stem cells and tantalum implants to provide structural integrity and to speed bony creeping substitution. Calcium phosphate cement has been reported in the treatment of fractures, especially depressed tibial plateau fractures. It is slow to resorb and is gradually replaced by bone, allowing prolonged support of periarticular fractures during healing. We hypothesize that calcium phosphate cement in conjunction with standard decompression of osteonecrotic femoral head lesions can prevent collapse. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction Nontraumatic osteonecrosis of the femoral head typically affects males between the ages of 20 and 40 years. Often presenting as deep-seated groin pain, symptomatic osteonecrosis progresses to collapse in 75–85% of untreated patients [1–3]. Collapse leads to osteoarthritis and eventual total hip arthroplasty or salvage procedure in 80% of cases [3]. Because treatment options for advanced osteonecrosis are mainly limited to arthroplasty in this relatively young population, less invasive modalities have been developed to prevent collapse in early lesions. Originally described by Ficat and Arlet in 1964, core decompression reduces intra-osseous pressure, improves vascular flow to prevent further ischemia, and potentially enhances creeping substitution of necrotic areas [4]. It is successful in preventing collapse in 63% of patients [3]. Collapse of the articular surface of the femoral head is heralded by the collapse of subchondral trabeculae giving rise to the radiolucent crescent sign. Early attempts at remodeling of the osteonecrotic areas by adjacent normal bone are predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place [5]. Multiple adjuncts to core decompression, such as vascularized bone grafts, cancellous and cortical bone grafts, bone marrow aspirate, mesenchymal stem cells, bone morphogenic proteins (BMP), and porous tantalum implants, have been developed to quicken
* Corresponding author. Tel.: +1 614 293 3541; fax: +1 614 293 2910. E-mail address: [email protected] (T.J. Ellis). 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.10.039
the healing process in addition to providing structural support in some cases [4,6–9]. Hypothesis In this paper, we hypothesize that injectable calcium phosphate cement can be used to prevent collapse of the articular surface in patients with atraumatic osteonecrosis of the femoral head. Unlike current treatment modalities, it would both provide structural support and allow for bony substitution over time. Current treatment for osteonecrosis of the femoral head A recent survey of the American Association of Hip and Knee Surgeons revealed that among the wide array of treatments described for symptomatic pre-collapse osteonecrosis of the femoral head in young patients, core decompression was the most commonly offered intervention [12]. For Steinberg stage IIB, which correlates to moderate lucent and sclerotic changes in the femoral head without collapse and associated symptoms, 69% of surgeons offered core decompression, 30% with and 39% without bone graft or bone graft substitute, and a lesser percentage offered total hip arthroplasty or hip resurfacing [12]. Failure rates of adjuncts with core decompression have been reported from 0% to 18% for bone marrow cells or BMP, 14% to 16% for tantalum implants, 13% to 69% for nonvascularized bone grafting, and 0% to 88% for vascularized bone grafting [8]. There is a wide range of morbidity associated with the different adjunctive modalities; multiple
726
V.Y. Ng et al. / Medical Hypotheses 74 (2010) 725–726
small-diameter core decompression can be performed as an outpatient procedure, while vascularized fibular graft surgery typically requires 7 h of operative time [8]. Porous tantalum implants are designed to provide structural advantages of bone graft without the risk of disease transmission in allograft or the donor site morbidity of autograft. Long-term follow-up is lacking and there is concern regarding the conversion to total hip arthroplasty and the production of intra-articular metal debris [9]. The rationale and evidence for calcium phosphate cement Injectable bioresorbable calcium phosphate cement currently is used as a bone substitute in periarticular fracture fixation. Providing both immediate and lasting mechanical support, calcium phosphate cement prevents articular surface subsidence while it is gradually replaced by normal bone. The subchondral void created after elevation of the articular surface in depressed tibial plateau fractures may not be dissimilar to the decompressed defect or subchondral collapse seen in osteonecrosis of the femoral head. To our knowledge, calcium phosphate cement used in conjunction with decompression of osteonecrosis of the femoral head to prevent collapse has not been reported previously in the English-language literature. HydroSetÒ is a blend of powder tetracalcium phosphate and liquid sodium phosphate with several other ingredients that hardens without an exothermic reaction to form hydroxyapatite. As the cement is injected, it interdigitates with the surrounding bone, achieving its full compressive strength of 15–17 mPA at 24 h. This is stronger than cancellous bone, but weaker than cortical bone [13,14]. Welch et al. found that calcium phosphate cement maintained articular congruency better than autologous bone graft in experimentally created subchondral tibial plateau defects in goats [15]. This finding was confirmed in humans by Russell et al. [16]. Gradual resorption by vascular penetration and bone formation is an important component of using calcium phosphate cement. Wood et al. found a high failure rate, 27% at 1.7 years, in patients with stage III osteonecrosis of the femoral head treated with the more permanent and less osteotransductive methylmethacrylate cement [17]. Rijnen et al. created experimental subchondral defects in the femoral heads of goats and filled them with a mixture of morsellized cancellous bone and calcium phosphate [14]. Unfortunately, while the calcium phosphate cement/morsellized cancellous bone mixture was resorbed as rapidly as plain morsellized cancellous bone, there was less formation of new trabecular bone in the mixture group at 12 weeks. The outcome of calcium phosphate cement alone, however, was not examined [14]. Huang et al., in a Chineselanguage study on patients with stages I–III osteonecrosis, used core decompression and calcium phosphate cement as a drug delivery system for a traditional herbal medicine, Danshen (Salvia miltiorrhiza), thought to improve blood circulation [18,19]. Their results were described as excellent or good in 92.6% of cases [18]. Perspectives Currently, successful treatment with decompression of early stage atraumatic osteonecrosis of the femoral head depends on
re-ossification of the subchondral void occurring before articular collapse. Based on the trauma literature for periarticular fractures in other body locations, we expect injectable calcium phosphate cement would provide long lasting structural support and at the same time allow for eventual substitution of bone. Evaluation of our hypothesis would require a long-term study as the natural history of this disease process can take several years. Calcium phosphate and other osteoconductive materials have recently played an important role in other areas of orthopaedics and we believe the trend can extend to this field as well. Conflict of interest statement None declared. Appendix A. Supplementary material Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.mehy.2009.10.039. References [1] Mont MA, Hungerford DS. Non-traumatic avascular necrosis of the femoral head. J Bone Joint Surg Am 1995;77(3):459–74. [2] Merle D’Aubigne R, Postel M, Mazabraud A, Massias P, Gueguen J, France P. Idiopathic necrosis of the femoral head in adults. J Bone Joint Surg Br 1965;47(4):612–33. [3] Mont MA, Carbone JJ, Fairbank AC. Core decompression versus nonoperative management for osteonecrosis of the hip. Clin Orthop Relat Res 1996;324(3):169–78. [4] Parsons S, Steele N. Osteonecrosis of the femoral head: part 2 – options for treatment. Curr Ortho 2008;22(5):349–58. [5] Parsons S, Steele N. Osteonecrosis of the femoral head: part 1 – aetiology, pathogenesis, investigation, classification. Curr Ortho 2007;21(6):457–63. [6] Keizer SB, Kock NB, Dijkstra PD, Taminiau AH, Nelissen RG. Treatment of avascular necrosis of the hip by a non-vascularised cortical graft. J Bone Joint Surg Br 2006;88(4):460–6. [7] Mont MA, Einhorn TA, Sponseller PD, Hungerford DS. The trapdoor procedure using autogenous cortical and cancellous bone grafts for osteonecrosis of the femoral head. J Bone Joint Surg Br 1998;80(1):56–62. [8] Marker DR, Seyler TM, McGrath MS, Delanois RE, Ulrich SD, Mont MA. Treatment of early stage osteonecrosis of the femoral head. J Bone Joint Surg Am 2008;90(Suppl. 4):175–87. [9] Petrigliano FA, Lieberman JR. Osteonecrosis of the hip: novel approaches to evaluation and treatment. Clin Orthop Relat Res 2007;465:53–62. [12] McGrory BJ, York SC, Iorio R, et al. Current practices of AAHKS members in the treatment of adult osteonecrosis of the femoral head. J Bone Joint Surg Am 2007;89(6):1194–204. [13] Larsson S, Bauer TW. Use of injectable calcium phosphate cement for fracture fixation: a review. Clin Orthop Relat Res 2002;395:23–32. [14] Rijnen WH, Gardeniers JW, Schreurs BW, Buma P. Impacted bone and calcium phosphate cement for repair of femoral head defects: a pilot study. Clin Orthop Relat Res 2007;459:216–21. [15] Welch RD, Zhang H, Bronson DG. Experimental tibial plateau fractures augmented with calcium phosphate cement or autologous bone graft. J Bone Joint Surg Am 2003;85-A(2):222–31. [16] Russell TA, Leighton RK. Comparison of autogenous bone graft and endothermic calcium phosphate cement for defect augmentation in tibial plateau fractures. A multicenter, prospective, randomized study. J Bone Joint Surg Am 2008;90(10):2057–61. [17] Wood ML, Dowell CM, Kelley SS. Cementation for femoral head osteonecrosis: a preliminary clinic study. Clin Orthop Relat Res 2003;412:94–102. [18] Huang X, Jiang H, Liu D, Zhou Z, Wang L. Implantation of calcium phosphate cement/Danshen drug delivery system for avascular necrosis of femoral head. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2008;22(3):307–10. [19] Zhou L, Zuo Z, Chow MS. Danshen: an overview of its chemistry, pharmacology, pharmacokinetics, and clinical use. J Clin Pharmacol 2005;45(12):1345–59.
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Calcium phosphate cement to prevent collapse in avascular necrosis of the femoral head Vincent Y. Ng, Jeffrey F. Granger, Thomas J. Ellis * Department of Orthopaedics, The Ohio State University Medical Center, 2050 Kenny Road, Columbus, OH 43221, United States
a r t i c l e
i n f o
Article history: Received 21 October 2009 Accepted 26 October 2009
s u m m a r y Subchondral and articular collapse following nontraumatic osteonecrosis of the femoral head is an important cause of osteoarthritis in patients between ages 20 and 40. Because hip arthroplasty in the younger population is prone to early wear and failure, it is paramount to prevent collapse once osteonecrosis is detected. Natural remodeling of the osteonecrotic areas by adjacent normal bone is predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place. Current treatment modalities include core decompression and various adjuncts such as bone graft, mesenchymal stem cells and tantalum implants to provide structural integrity and to speed bony creeping substitution. Calcium phosphate cement has been reported in the treatment of fractures, especially depressed tibial plateau fractures. It is slow to resorb and is gradually replaced by bone, allowing prolonged support of periarticular fractures during healing. We hypothesize that calcium phosphate cement in conjunction with standard decompression of osteonecrotic femoral head lesions can prevent collapse. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction Nontraumatic osteonecrosis of the femoral head typically affects males between the ages of 20 and 40 years. Often presenting as deep-seated groin pain, symptomatic osteonecrosis progresses to collapse in 75–85% of untreated patients [1–3]. Collapse leads to osteoarthritis and eventual total hip arthroplasty or salvage procedure in 80% of cases [3]. Because treatment options for advanced osteonecrosis are mainly limited to arthroplasty in this relatively young population, less invasive modalities have been developed to prevent collapse in early lesions. Originally described by Ficat and Arlet in 1964, core decompression reduces intra-osseous pressure, improves vascular flow to prevent further ischemia, and potentially enhances creeping substitution of necrotic areas [4]. It is successful in preventing collapse in 63% of patients [3]. Collapse of the articular surface of the femoral head is heralded by the collapse of subchondral trabeculae giving rise to the radiolucent crescent sign. Early attempts at remodeling of the osteonecrotic areas by adjacent normal bone are predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place [5]. Multiple adjuncts to core decompression, such as vascularized bone grafts, cancellous and cortical bone grafts, bone marrow aspirate, mesenchymal stem cells, bone morphogenic proteins (BMP), and porous tantalum implants, have been developed to quicken
* Corresponding author. Tel.: +1 614 293 3541; fax: +1 614 293 2910. E-mail address: [email protected] (T.J. Ellis). 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.10.039
the healing process in addition to providing structural support in some cases [4,6–9]. Hypothesis In this paper, we hypothesize that injectable calcium phosphate cement can be used to prevent collapse of the articular surface in patients with atraumatic osteonecrosis of the femoral head. Unlike current treatment modalities, it would both provide structural support and allow for bony substitution over time. Current treatment for osteonecrosis of the femoral head A recent survey of the American Association of Hip and Knee Surgeons revealed that among the wide array of treatments described for symptomatic pre-collapse osteonecrosis of the femoral head in young patients, core decompression was the most commonly offered intervention [12]. For Steinberg stage IIB, which correlates to moderate lucent and sclerotic changes in the femoral head without collapse and associated symptoms, 69% of surgeons offered core decompression, 30% with and 39% without bone graft or bone graft substitute, and a lesser percentage offered total hip arthroplasty or hip resurfacing [12]. Failure rates of adjuncts with core decompression have been reported from 0% to 18% for bone marrow cells or BMP, 14% to 16% for tantalum implants, 13% to 69% for nonvascularized bone grafting, and 0% to 88% for vascularized bone grafting [8]. There is a wide range of morbidity associated with the different adjunctive modalities; multiple
726
V.Y. Ng et al. / Medical Hypotheses 74 (2010) 725–726
small-diameter core decompression can be performed as an outpatient procedure, while vascularized fibular graft surgery typically requires 7 h of operative time [8]. Porous tantalum implants are designed to provide structural advantages of bone graft without the risk of disease transmission in allograft or the donor site morbidity of autograft. Long-term follow-up is lacking and there is concern regarding the conversion to total hip arthroplasty and the production of intra-articular metal debris [9]. The rationale and evidence for calcium phosphate cement Injectable bioresorbable calcium phosphate cement currently is used as a bone substitute in periarticular fracture fixation. Providing both immediate and lasting mechanical support, calcium phosphate cement prevents articular surface subsidence while it is gradually replaced by normal bone. The subchondral void created after elevation of the articular surface in depressed tibial plateau fractures may not be dissimilar to the decompressed defect or subchondral collapse seen in osteonecrosis of the femoral head. To our knowledge, calcium phosphate cement used in conjunction with decompression of osteonecrosis of the femoral head to prevent collapse has not been reported previously in the English-language literature. HydroSetÒ is a blend of powder tetracalcium phosphate and liquid sodium phosphate with several other ingredients that hardens without an exothermic reaction to form hydroxyapatite. As the cement is injected, it interdigitates with the surrounding bone, achieving its full compressive strength of 15–17 mPA at 24 h. This is stronger than cancellous bone, but weaker than cortical bone [13,14]. Welch et al. found that calcium phosphate cement maintained articular congruency better than autologous bone graft in experimentally created subchondral tibial plateau defects in goats [15]. This finding was confirmed in humans by Russell et al. [16]. Gradual resorption by vascular penetration and bone formation is an important component of using calcium phosphate cement. Wood et al. found a high failure rate, 27% at 1.7 years, in patients with stage III osteonecrosis of the femoral head treated with the more permanent and less osteotransductive methylmethacrylate cement [17]. Rijnen et al. created experimental subchondral defects in the femoral heads of goats and filled them with a mixture of morsellized cancellous bone and calcium phosphate [14]. Unfortunately, while the calcium phosphate cement/morsellized cancellous bone mixture was resorbed as rapidly as plain morsellized cancellous bone, there was less formation of new trabecular bone in the mixture group at 12 weeks. The outcome of calcium phosphate cement alone, however, was not examined [14]. Huang et al., in a Chineselanguage study on patients with stages I–III osteonecrosis, used core decompression and calcium phosphate cement as a drug delivery system for a traditional herbal medicine, Danshen (Salvia miltiorrhiza), thought to improve blood circulation [18,19]. Their results were described as excellent or good in 92.6% of cases [18]. Perspectives Currently, successful treatment with decompression of early stage atraumatic osteonecrosis of the femoral head depends on
re-ossification of the subchondral void occurring before articular collapse. Based on the trauma literature for periarticular fractures in other body locations, we expect injectable calcium phosphate cement would provide long lasting structural support and at the same time allow for eventual substitution of bone. Evaluation of our hypothesis would require a long-term study as the natural history of this disease process can take several years. Calcium phosphate and other osteoconductive materials have recently played an important role in other areas of orthopaedics and we believe the trend can extend to this field as well. Conflict of interest statement None declared. Appendix A. Supplementary material Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.mehy.2009.10.039. References [1] Mont MA, Hungerford DS. Non-traumatic avascular necrosis of the femoral head. J Bone Joint Surg Am 1995;77(3):459–74. [2] Merle D’Aubigne R, Postel M, Mazabraud A, Massias P, Gueguen J, France P. Idiopathic necrosis of the femoral head in adults. J Bone Joint Surg Br 1965;47(4):612–33. [3] Mont MA, Carbone JJ, Fairbank AC. Core decompression versus nonoperative management for osteonecrosis of the hip. Clin Orthop Relat Res 1996;324(3):169–78. [4] Parsons S, Steele N. Osteonecrosis of the femoral head: part 2 – options for treatment. Curr Ortho 2008;22(5):349–58. [5] Parsons S, Steele N. Osteonecrosis of the femoral head: part 1 – aetiology, pathogenesis, investigation, classification. Curr Ortho 2007;21(6):457–63. [6] Keizer SB, Kock NB, Dijkstra PD, Taminiau AH, Nelissen RG. Treatment of avascular necrosis of the hip by a non-vascularised cortical graft. J Bone Joint Surg Br 2006;88(4):460–6. [7] Mont MA, Einhorn TA, Sponseller PD, Hungerford DS. The trapdoor procedure using autogenous cortical and cancellous bone grafts for osteonecrosis of the femoral head. J Bone Joint Surg Br 1998;80(1):56–62. [8] Marker DR, Seyler TM, McGrath MS, Delanois RE, Ulrich SD, Mont MA. Treatment of early stage osteonecrosis of the femoral head. J Bone Joint Surg Am 2008;90(Suppl. 4):175–87. [9] Petrigliano FA, Lieberman JR. Osteonecrosis of the hip: novel approaches to evaluation and treatment. Clin Orthop Relat Res 2007;465:53–62. [12] McGrory BJ, York SC, Iorio R, et al. Current practices of AAHKS members in the treatment of adult osteonecrosis of the femoral head. J Bone Joint Surg Am 2007;89(6):1194–204. [13] Larsson S, Bauer TW. Use of injectable calcium phosphate cement for fracture fixation: a review. Clin Orthop Relat Res 2002;395:23–32. [14] Rijnen WH, Gardeniers JW, Schreurs BW, Buma P. Impacted bone and calcium phosphate cement for repair of femoral head defects: a pilot study. Clin Orthop Relat Res 2007;459:216–21. [15] Welch RD, Zhang H, Bronson DG. Experimental tibial plateau fractures augmented with calcium phosphate cement or autologous bone graft. J Bone Joint Surg Am 2003;85-A(2):222–31. [16] Russell TA, Leighton RK. Comparison of autogenous bone graft and endothermic calcium phosphate cement for defect augmentation in tibial plateau fractures. A multicenter, prospective, randomized study. J Bone Joint Surg Am 2008;90(10):2057–61. [17] Wood ML, Dowell CM, Kelley SS. Cementation for femoral head osteonecrosis: a preliminary clinic study. Clin Orthop Relat Res 2003;412:94–102. [18] Huang X, Jiang H, Liu D, Zhou Z, Wang L. Implantation of calcium phosphate cement/Danshen drug delivery system for avascular necrosis of femoral head. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2008;22(3):307–10. [19] Zhou L, Zuo Z, Chow MS. Danshen: an overview of its chemistry, pharmacology, pharmacokinetics, and clinical use. J Clin Pharmacol 2005;45(12):1345–59.