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Total Knee Arthroplasty in Osteopetrosis Using Patient-Specific Instrumentation
The Journal of Arthroplasty Vol. 27 No. 8 2012
Case Report
Total Knee Arthroplasty in Osteopetrosis Using Patient-Specific Instrumentation Stephanie W. Mayer, MD, Kevin T. Hug, BS, Benjamin J. Hansen, MD, and Michael P. Bolognesi, MD
Abstract: Osteopetrosis is an uncommon endocrine disease characterized by defective osteoclast resorption of bones. This causes a hard, sclerotic, and brittle bone throughout the skeleton. Fractures and unforgiving subchondral bone are common in this condition, both of which can lead to osteoarthritis. Total knee arthroplasty is often the treatment of choice but presents challenges due to the hard and sclerotic bone present throughout the metaphysis and diaphysis of the femur and the tibia. We present a case of knee osteoarthritis in a patient with osteopetrosis who underwent total knee arthroplasty using patient-specific instrumentation. This technique eliminates intramedullary alignment and minimizes drilling, reaming, and saw passes, making it attractive in the setting of diseases such as osteopetrosis to decrease operative time and potential complications. Keywords: total knee arthroplasty, osteopetrosis, patient-specific instrumentation. © 2012 Elsevier Inc. All rights reserved.
Osteopetrosis, also known as marble bone disease and Albers-Schonberg disease, is an uncommon, heritable skeletal condition first described in 1904 by Dr AlbersSchönberg, a German radiologist [1,2]. In most forms, it is characterized by defective osteoclasts, which are unable to form the acidic, ruffled border necessary to resorb calcified cartilage during childhood and bone during adulthood. This results in an inhibition of bone turnover and remodeling, leading to bones made of disorganized calcified cartilage with immature, thickened trabeculae and cortices. Despite its thickened and sclerotic nature, it is substantially weaker and more brittle than a normal bone. Disruption of bone metabolism results in clinical manifestations including multiple recurrent fractures, osteoarthritis, osteomyelitis, and obliteration of the medullary cavity [1,2]. The 3 main types of osteopetrosis are classified as infantile malignant, intermediate, and benign. The malignant autosomal recessive form of this disease results in death in the first decade of life. The From the Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC. Submitted July 10, 2011; accepted December 10, 2011. The Conflict of Interest statement associated with this article can be found at doi:10.1016/j.arth.2011.12.007. Reprint requests: Stephanie W. Mayer, MD, Department of Orthopaedic Surgery, Duke University Medical Center, 200 Trent Dr Box 3269, Durham, NC 27710. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0026$36.00/0 doi:10.1016/j.arth.2011.12.007
intermediate autosomal recessive form carries a life expectancy into adulthood and has the highest incidence of osteomyelitis of the jaw. The benign autosomal dominant form is the most common and typically carries a full life expectancy, however, with increased propensity for fractures and other musculoskeletal problems. Radiographic traits of osteopetrosis include increased bone density, osteosclerosis, metaphyseal widening, endobone formation, and skull-base and vertebral endplate thickening [3]. Degenerative osteoarthritis is a commonly encountered complication of long-standing osteopetrosis [4]. Total knee arthroplasty (TKA) remains a good option for these patients, but there are unique challenges even during what would otherwise be a routine procedure due to replacement of cancellous bone with hard, sclerotic trabeculae and cortical bone and, therefore, obliteration of the cancellous bone of the medullary canal and the metaphyseal regions. These challenges consist of reaming of the femoral canal, drilling for multiple pins to secure jigs, and challenging saw resections of the distal femur and proximal tibia. These obstacles can lead to malpositioned components and inadequate surfaces for cement interdigitation. To circumvent these obstacles, surgeons have used external alignment guides, customized implant components with smaller stems, and computer-assisted navigation techniques and have reported successful outcomes in shortand medium-term follow-up in several case reports
1580.e1
1580.e2 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 [5-7]. In each of these techniques, the intraoperative goal was to minimize the amount of drilling, reaming, and saw passes while still achieving appropriate alignment and ingrowth surfaces for the components. We report the use of patient-specific instrumentation (PSI; Zimmer, Warsaw, Ind) for TKA in an osteopetrosis patient as another alternative to minimize these difficult and time-consuming steps. PSI uses a preoperative longaxis magnetic resonance imaging (MRI), which is used to manufacture unique cutting jigs specific to a patient's femoral and tibial anatomy through the use of rapid prototyping technology (Fig. 1A-C). This allows the surgeon to use one set of jigs that are predesigned to contour to the patient's distal femur and proximal tibia to perform the appropriate femoral and tibial resections. This eliminates the need to ream the intramedullary canal for an alignment guide, minimizes the number of femoral and tibial pins necessary for securing cutting jigs, and reduces the number of saw blade passes because the guide is fabricated for a predetermined resection. Short-term results from a feasibility trial and case series using a similar approach for routine TKA suggest that the procedure achieves the same level of precision in component placement as the conventional TKA technique [8].
Case Report We report on a 58-year-old man with osteopetrosis who presented to the orthopaedic clinic at our institution with bilateral, right greater-than-left, knee pain. His pain and effusions had been persistent for several years, beginning during a period of increased physical activity. He had previously been evaluated by an outside orthopedist who initially suspected meniscal pathology and, after an MRI, recommended right knee arthroscopy. At the time of surgery, degenerative meniscal tears,
as well as extensive lateral compartment chondral loss, was noted. He was subsequently managed with aspirations for recurrent effusions and steroid injections, both of which provided short-lived relief. He was referred to our institution for consideration of TKA, given his diagnosis of osteopetrosis. At the time of our initial evaluation, he was noted to have a partially correctable clinical valgus deformity and a 7° flexion contracture with active flexion to 120°. He had no neurovascular compromise in either lower extremity. On plain film imaging, approximately 10° of overall valgus deformity with mild osteophyte formation and mild lateral joint space narrowing was observed (Fig. 2A). Because of his localizing symptoms and history of failed conservative management in the face of known full-thickness chondral lesions by arthroscopy, a TKA was recommended. His history of osteopetrosis caused concern for challenges with intramedullary guide rod placement for positioning of femoral component cutting jigs, placement of the tibial component keel, drilling for pins, and the possibility of multiple resections for soft tissue balancing. It was felt that PSI was a good option in this case. After the risks and benefits of the procedure were explained to the patient, he was consented for TKA using PSI. He underwent a routine MRI for preoperative fabrication of custom-cutting blocks (Figs. 1B, C) and was taken to the operating room where a right TKA was performed using a standard medial parapatellar approach. Zimmer Gender Solutions NexGen High-Flex Knee Implants and posterior cruciate ligament–sacrificing NexGen High-Flex Knee Implants were used. The implanted components consisted of a size 4 genderspecific male femur, size 3 tibia, and 9-mm ultracongruent high-molecular-weight highly cross-linked tibial polyethylene insert. Despite the use of PSI, there was difficulty in drilling even for the limited numbers of pins
Fig. 1. (A) Screenshot of the PSI planning software for cutting jig design. Completed patient-specific cutting jigs fabricated for our patient's distal femur (B) and (C) tibial plateau.
TKA in Osteopetrosis Using Patient-Specific Instrumentation Mayer et al
1580.e3
Fig. 2. (A) Preoperative long-standing radiograph. Note the sclerosis and medullary canal obliteration of the femur and tibia characteristic of osteopetrosis. (B) Three-month long-standing radiograph after TKA using the PSI technique. (C) Six-month postoperative anteroposterior view. (D) Six-month postoperative lateral view.
required for the femoral and tibial cutting guides. In total, three drill bits were used for this purpose. Similarly, the tibial and femoral cuts through the subchondral bone were challenging, and four saw blades were needed. Nine batteries were used during the case for the drills, reamers, and saw. Preparing the tibial canal for the keel required a high-speed burr rather than the standard reamer and punch to adequately create space and prevent fracture when placing the final tibial implant. No significant patellar chondromalacia or cartilage loss was noted, and it was decided that the patella would be left unresurfaced. Trial components were placed, and the sizing and soft tissue balancing were felt to be satisfactory. After the removal of the femoral trial component, a fracture of the medial condyle was noted emanating from the femoral component lug hole used in this system for femoral component positioning. This fracture was captured nicely by the final femoral component and did not cause problems with the final component fit, and the components were able to be cemented in appropriate alignment. The usual postoperative protocol was changed from weight bearing as tolerated to partial weight bearing with range of motion as tolerated for six weeks to protect the medial condyle fracture, and the patient recovered uneventfully and was discharged home on postoperative day three. At six weeks postoperatively, he was transitioned to weight bearing as tolerated with no further complications. At the time of this manuscript, he was doing well six months postoperatively. His range of motion was reported by physical therapy at 0° to 130°; he rated his pain as a 2 of 10 and described it as
occasional and worst at night after a day of activity. He was able to walk an unlimited distance and was using no assistive device. His implants remained in good alignment without radiographic evidence of loosening. (Figs. 2B, D). His medial condyle fracture appeared healed radiographically. Permission was granted by the patient for use of medical information in this case report.
Discussion Degenerative osteoarthritis is common in patients with osteopetrosis [4]. This may develop as a result of skeletal deformities such as coxa vara, anomalous fracture callous causing malunion, and nonunion [9]. It can also occur in the absence of deformity due to compression of articular cartilage onto hard and unforgiving subchondral bone seen in this disease [3,14]. Symptomatic osteoarthritis in this patient population may be considered for treatment with total joint arthroplasty. However, osteopetrosis is recognized to create unique technical difficulties and possible complications in arthroplasty. Obliteration of the medullary canal can make intramedullary guide placement and reaming challenging and can compromise the final femoral or tibial stem placement. The cancellous bone presented after resection is abnormal and sclerotic; therefore, a proper cementing technique is important. Brittle bone can increase the risk for iatrogenic fracture, and disordered bone turnover impedes fracture healing should it occur. In addition, overheating and breakage of drill bits, as well as longer surgical time, are often encountered. For total hip arthroplasty, the average surgical time was reported as nearly 5 hours in one article [10].
1580.e4 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Finally, these patients are known to be at higher risk of osteomyelitis because of poor blood flow through the obliterated medullary canal and relative neutropenia. It should be noted, however, that in the few published reports on total joint arthroplasty in osteopetrosis, there are no cases of postoperative osteomyelitis. At this time, there is a paucity of information available about hip and knee arthroplasty in patients with osteopetrosis. Currently, there are 11 articles in English literature reporting joint arthroplasty in patients with osteopetrosis consisting of case reports and case series only. These articles consist of 19 hip arthroplasties in 13 patients [4-7,10-13], one hip resurfacing [14], and three knee arthroplasties in three patients [10,15]. Overall, these procedures have proven difficult but have shown successful outcomes. A review of these cases demonstrated stable implants and no major complications with follow-up as long as six years [10]. Surgical technique differed considerably among the case reports because surgeons attempted to circumvent the problems associated with osteopetrosis in arthroplasty. For total hip arthroplasty, one author described shortened femoral stems to minimize reaming of the femoral canal [4]. Egawa et al [5] reported the use of computer-assisted fluoroscopic navigation to aid in the creation of a femoral canal with a high-speed burr. Benum et al [7] designed a computed tomography– based customized femoral component for use in total hip arthroplasty, which was compatible with the patient's unique bone geometry. No advanced technology has been described for TKA; however, changes in instrumentation and surgical tools are described. External femoral alignment guides were implemented in two cases of primary cemented TKA [10]. These authors discussed the use of external alignment guides due to the hard medullary canal, difficult bone cuts, and the use of a high-speed burr instead of the standard broach for the tibial keel. Outcomes included one patient with an uncomplicated postoperative course and a good motion and pain relief at 2-year follow-up, and the need for postoperative manipulation under anesthesia in the other patient with subsequent excellent outcome at 20year follow-up. One previous report of TKA in a patient with osteopetrosis reported similar challenges but stable implants with pain relief at two-year follow-up [15]. We report the use of PSI in TKA to minimize the difficulty caused by the characteristics of bones in patients with osteopetrosis. The use of prefabricated cutting jigs eliminates the need to ream the femoral canal and reduces the number of pin sites to be drilled. In addition,
the MRI-based design system provides accurate bone resections built into the customized jigs, which are often difficult to achieve through conventional methods and often need intraoperative revisions resulting in multiple difficult saw passes. This technique provides innovative solutions to the unique challenges encountered while performing TKA in patients with osteopetrosis and, given the satisfactory outcome in this patient, appears to be an option in this situation.
References 1. Tolar J, Teitelbaum SL, Orchard PJ. Osteopetrosis. N Engl J Med 2004;351:2839. 2. Shapiro F. Osteopetrosis. Current clinical considerations. Clin Orthop Relat Res 1993;294:34. 3. Landa J, Margolis N, Di Cesare P. Orthopaedic management of the patient with osteopetrosis. J Am Acad Orthop Surg 2007;15. 4. Cameron HU, Dewar FP. Degenerative osteoarthritis associated with osteopetrosis. Clin Orthop Relat Res 1977;127:148. 5. Egawa H, Nakano S, Hamada D, et al. Total hip arthroplasty in osteopetrosis using computer-assisted fluoroscopic navigation. J Arthroplasty 2005;20:1074. 6. Gwynne Jones DP, Hodgson BF, et al. Bilateral, uncemented total hip arthroplasty in osteopetrosis. J Bone Joint Surg Br 2004;86:276. 7. Benum P, Aamodt A, Nordsletten L. Customised femoral stems in osteopetrosis and the development of a guiding system for the preparation of an intramedullary cavity: a report of two cases. J Bone Joint Surg Br 2010;92:1303. 8. Lombardi AV, Berend KR, Adams JB. Patient-specific approach in total knee arthroplasty. Orthopedics 2008;31: 927. 9. de Palma L, Tulli A, Maccauro G, et al. Fracture callus in osteopetrosis. Clin Orthop Relat Res 1994;308:85. 10. Strickland JP, Berry DJ. Total joint arthroplasty in patients with osteopetrosis: a report of 5 cases and review of the literature. J Arthroplasty 2005;20:815. 11. Matsuno T, Katayama N. Osteopetrosis and total hip arthroplasty. Report of two cases. Int Orthop 1997;21:409. 12. Janecki CJ, Nelson CL. Osteoarthritis associated with osteopetrosis treated by total hip replacement arthroplasty. Report of a case. Clevel Clin Q 1971;38:169. 13. Ashby ME. Total hip arthroplasty in osteopetrosis. A report of two cases. Clin Orthop Relat Res 1992;214. 14. Girard J, Vendittoli PA, Lavigne M, et al. Resurfacing arthroplasty of the hip in osteopetrosis. J Bone Joint Surg Br 2006;88:818. 15. Casden AM, Jaffe FF, Kastenbaum DM, et al. Osteoarthritis associated with osteopetrosis treated by total knee arthroplasty. Report of a case. Clin Orthop Relat Res 1989; 202.
Case Report
Total Knee Arthroplasty in Osteopetrosis Using Patient-Specific Instrumentation Stephanie W. Mayer, MD, Kevin T. Hug, BS, Benjamin J. Hansen, MD, and Michael P. Bolognesi, MD
Abstract: Osteopetrosis is an uncommon endocrine disease characterized by defective osteoclast resorption of bones. This causes a hard, sclerotic, and brittle bone throughout the skeleton. Fractures and unforgiving subchondral bone are common in this condition, both of which can lead to osteoarthritis. Total knee arthroplasty is often the treatment of choice but presents challenges due to the hard and sclerotic bone present throughout the metaphysis and diaphysis of the femur and the tibia. We present a case of knee osteoarthritis in a patient with osteopetrosis who underwent total knee arthroplasty using patient-specific instrumentation. This technique eliminates intramedullary alignment and minimizes drilling, reaming, and saw passes, making it attractive in the setting of diseases such as osteopetrosis to decrease operative time and potential complications. Keywords: total knee arthroplasty, osteopetrosis, patient-specific instrumentation. © 2012 Elsevier Inc. All rights reserved.
Osteopetrosis, also known as marble bone disease and Albers-Schonberg disease, is an uncommon, heritable skeletal condition first described in 1904 by Dr AlbersSchönberg, a German radiologist [1,2]. In most forms, it is characterized by defective osteoclasts, which are unable to form the acidic, ruffled border necessary to resorb calcified cartilage during childhood and bone during adulthood. This results in an inhibition of bone turnover and remodeling, leading to bones made of disorganized calcified cartilage with immature, thickened trabeculae and cortices. Despite its thickened and sclerotic nature, it is substantially weaker and more brittle than a normal bone. Disruption of bone metabolism results in clinical manifestations including multiple recurrent fractures, osteoarthritis, osteomyelitis, and obliteration of the medullary cavity [1,2]. The 3 main types of osteopetrosis are classified as infantile malignant, intermediate, and benign. The malignant autosomal recessive form of this disease results in death in the first decade of life. The From the Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC. Submitted July 10, 2011; accepted December 10, 2011. The Conflict of Interest statement associated with this article can be found at doi:10.1016/j.arth.2011.12.007. Reprint requests: Stephanie W. Mayer, MD, Department of Orthopaedic Surgery, Duke University Medical Center, 200 Trent Dr Box 3269, Durham, NC 27710. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0026$36.00/0 doi:10.1016/j.arth.2011.12.007
intermediate autosomal recessive form carries a life expectancy into adulthood and has the highest incidence of osteomyelitis of the jaw. The benign autosomal dominant form is the most common and typically carries a full life expectancy, however, with increased propensity for fractures and other musculoskeletal problems. Radiographic traits of osteopetrosis include increased bone density, osteosclerosis, metaphyseal widening, endobone formation, and skull-base and vertebral endplate thickening [3]. Degenerative osteoarthritis is a commonly encountered complication of long-standing osteopetrosis [4]. Total knee arthroplasty (TKA) remains a good option for these patients, but there are unique challenges even during what would otherwise be a routine procedure due to replacement of cancellous bone with hard, sclerotic trabeculae and cortical bone and, therefore, obliteration of the cancellous bone of the medullary canal and the metaphyseal regions. These challenges consist of reaming of the femoral canal, drilling for multiple pins to secure jigs, and challenging saw resections of the distal femur and proximal tibia. These obstacles can lead to malpositioned components and inadequate surfaces for cement interdigitation. To circumvent these obstacles, surgeons have used external alignment guides, customized implant components with smaller stems, and computer-assisted navigation techniques and have reported successful outcomes in shortand medium-term follow-up in several case reports
1580.e1
1580.e2 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 [5-7]. In each of these techniques, the intraoperative goal was to minimize the amount of drilling, reaming, and saw passes while still achieving appropriate alignment and ingrowth surfaces for the components. We report the use of patient-specific instrumentation (PSI; Zimmer, Warsaw, Ind) for TKA in an osteopetrosis patient as another alternative to minimize these difficult and time-consuming steps. PSI uses a preoperative longaxis magnetic resonance imaging (MRI), which is used to manufacture unique cutting jigs specific to a patient's femoral and tibial anatomy through the use of rapid prototyping technology (Fig. 1A-C). This allows the surgeon to use one set of jigs that are predesigned to contour to the patient's distal femur and proximal tibia to perform the appropriate femoral and tibial resections. This eliminates the need to ream the intramedullary canal for an alignment guide, minimizes the number of femoral and tibial pins necessary for securing cutting jigs, and reduces the number of saw blade passes because the guide is fabricated for a predetermined resection. Short-term results from a feasibility trial and case series using a similar approach for routine TKA suggest that the procedure achieves the same level of precision in component placement as the conventional TKA technique [8].
Case Report We report on a 58-year-old man with osteopetrosis who presented to the orthopaedic clinic at our institution with bilateral, right greater-than-left, knee pain. His pain and effusions had been persistent for several years, beginning during a period of increased physical activity. He had previously been evaluated by an outside orthopedist who initially suspected meniscal pathology and, after an MRI, recommended right knee arthroscopy. At the time of surgery, degenerative meniscal tears,
as well as extensive lateral compartment chondral loss, was noted. He was subsequently managed with aspirations for recurrent effusions and steroid injections, both of which provided short-lived relief. He was referred to our institution for consideration of TKA, given his diagnosis of osteopetrosis. At the time of our initial evaluation, he was noted to have a partially correctable clinical valgus deformity and a 7° flexion contracture with active flexion to 120°. He had no neurovascular compromise in either lower extremity. On plain film imaging, approximately 10° of overall valgus deformity with mild osteophyte formation and mild lateral joint space narrowing was observed (Fig. 2A). Because of his localizing symptoms and history of failed conservative management in the face of known full-thickness chondral lesions by arthroscopy, a TKA was recommended. His history of osteopetrosis caused concern for challenges with intramedullary guide rod placement for positioning of femoral component cutting jigs, placement of the tibial component keel, drilling for pins, and the possibility of multiple resections for soft tissue balancing. It was felt that PSI was a good option in this case. After the risks and benefits of the procedure were explained to the patient, he was consented for TKA using PSI. He underwent a routine MRI for preoperative fabrication of custom-cutting blocks (Figs. 1B, C) and was taken to the operating room where a right TKA was performed using a standard medial parapatellar approach. Zimmer Gender Solutions NexGen High-Flex Knee Implants and posterior cruciate ligament–sacrificing NexGen High-Flex Knee Implants were used. The implanted components consisted of a size 4 genderspecific male femur, size 3 tibia, and 9-mm ultracongruent high-molecular-weight highly cross-linked tibial polyethylene insert. Despite the use of PSI, there was difficulty in drilling even for the limited numbers of pins
Fig. 1. (A) Screenshot of the PSI planning software for cutting jig design. Completed patient-specific cutting jigs fabricated for our patient's distal femur (B) and (C) tibial plateau.
TKA in Osteopetrosis Using Patient-Specific Instrumentation Mayer et al
1580.e3
Fig. 2. (A) Preoperative long-standing radiograph. Note the sclerosis and medullary canal obliteration of the femur and tibia characteristic of osteopetrosis. (B) Three-month long-standing radiograph after TKA using the PSI technique. (C) Six-month postoperative anteroposterior view. (D) Six-month postoperative lateral view.
required for the femoral and tibial cutting guides. In total, three drill bits were used for this purpose. Similarly, the tibial and femoral cuts through the subchondral bone were challenging, and four saw blades were needed. Nine batteries were used during the case for the drills, reamers, and saw. Preparing the tibial canal for the keel required a high-speed burr rather than the standard reamer and punch to adequately create space and prevent fracture when placing the final tibial implant. No significant patellar chondromalacia or cartilage loss was noted, and it was decided that the patella would be left unresurfaced. Trial components were placed, and the sizing and soft tissue balancing were felt to be satisfactory. After the removal of the femoral trial component, a fracture of the medial condyle was noted emanating from the femoral component lug hole used in this system for femoral component positioning. This fracture was captured nicely by the final femoral component and did not cause problems with the final component fit, and the components were able to be cemented in appropriate alignment. The usual postoperative protocol was changed from weight bearing as tolerated to partial weight bearing with range of motion as tolerated for six weeks to protect the medial condyle fracture, and the patient recovered uneventfully and was discharged home on postoperative day three. At six weeks postoperatively, he was transitioned to weight bearing as tolerated with no further complications. At the time of this manuscript, he was doing well six months postoperatively. His range of motion was reported by physical therapy at 0° to 130°; he rated his pain as a 2 of 10 and described it as
occasional and worst at night after a day of activity. He was able to walk an unlimited distance and was using no assistive device. His implants remained in good alignment without radiographic evidence of loosening. (Figs. 2B, D). His medial condyle fracture appeared healed radiographically. Permission was granted by the patient for use of medical information in this case report.
Discussion Degenerative osteoarthritis is common in patients with osteopetrosis [4]. This may develop as a result of skeletal deformities such as coxa vara, anomalous fracture callous causing malunion, and nonunion [9]. It can also occur in the absence of deformity due to compression of articular cartilage onto hard and unforgiving subchondral bone seen in this disease [3,14]. Symptomatic osteoarthritis in this patient population may be considered for treatment with total joint arthroplasty. However, osteopetrosis is recognized to create unique technical difficulties and possible complications in arthroplasty. Obliteration of the medullary canal can make intramedullary guide placement and reaming challenging and can compromise the final femoral or tibial stem placement. The cancellous bone presented after resection is abnormal and sclerotic; therefore, a proper cementing technique is important. Brittle bone can increase the risk for iatrogenic fracture, and disordered bone turnover impedes fracture healing should it occur. In addition, overheating and breakage of drill bits, as well as longer surgical time, are often encountered. For total hip arthroplasty, the average surgical time was reported as nearly 5 hours in one article [10].
1580.e4 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Finally, these patients are known to be at higher risk of osteomyelitis because of poor blood flow through the obliterated medullary canal and relative neutropenia. It should be noted, however, that in the few published reports on total joint arthroplasty in osteopetrosis, there are no cases of postoperative osteomyelitis. At this time, there is a paucity of information available about hip and knee arthroplasty in patients with osteopetrosis. Currently, there are 11 articles in English literature reporting joint arthroplasty in patients with osteopetrosis consisting of case reports and case series only. These articles consist of 19 hip arthroplasties in 13 patients [4-7,10-13], one hip resurfacing [14], and three knee arthroplasties in three patients [10,15]. Overall, these procedures have proven difficult but have shown successful outcomes. A review of these cases demonstrated stable implants and no major complications with follow-up as long as six years [10]. Surgical technique differed considerably among the case reports because surgeons attempted to circumvent the problems associated with osteopetrosis in arthroplasty. For total hip arthroplasty, one author described shortened femoral stems to minimize reaming of the femoral canal [4]. Egawa et al [5] reported the use of computer-assisted fluoroscopic navigation to aid in the creation of a femoral canal with a high-speed burr. Benum et al [7] designed a computed tomography– based customized femoral component for use in total hip arthroplasty, which was compatible with the patient's unique bone geometry. No advanced technology has been described for TKA; however, changes in instrumentation and surgical tools are described. External femoral alignment guides were implemented in two cases of primary cemented TKA [10]. These authors discussed the use of external alignment guides due to the hard medullary canal, difficult bone cuts, and the use of a high-speed burr instead of the standard broach for the tibial keel. Outcomes included one patient with an uncomplicated postoperative course and a good motion and pain relief at 2-year follow-up, and the need for postoperative manipulation under anesthesia in the other patient with subsequent excellent outcome at 20year follow-up. One previous report of TKA in a patient with osteopetrosis reported similar challenges but stable implants with pain relief at two-year follow-up [15]. We report the use of PSI in TKA to minimize the difficulty caused by the characteristics of bones in patients with osteopetrosis. The use of prefabricated cutting jigs eliminates the need to ream the femoral canal and reduces the number of pin sites to be drilled. In addition,
the MRI-based design system provides accurate bone resections built into the customized jigs, which are often difficult to achieve through conventional methods and often need intraoperative revisions resulting in multiple difficult saw passes. This technique provides innovative solutions to the unique challenges encountered while performing TKA in patients with osteopetrosis and, given the satisfactory outcome in this patient, appears to be an option in this situation.
References 1. Tolar J, Teitelbaum SL, Orchard PJ. Osteopetrosis. N Engl J Med 2004;351:2839. 2. Shapiro F. Osteopetrosis. Current clinical considerations. Clin Orthop Relat Res 1993;294:34. 3. Landa J, Margolis N, Di Cesare P. Orthopaedic management of the patient with osteopetrosis. J Am Acad Orthop Surg 2007;15. 4. Cameron HU, Dewar FP. Degenerative osteoarthritis associated with osteopetrosis. Clin Orthop Relat Res 1977;127:148. 5. Egawa H, Nakano S, Hamada D, et al. Total hip arthroplasty in osteopetrosis using computer-assisted fluoroscopic navigation. J Arthroplasty 2005;20:1074. 6. Gwynne Jones DP, Hodgson BF, et al. Bilateral, uncemented total hip arthroplasty in osteopetrosis. J Bone Joint Surg Br 2004;86:276. 7. Benum P, Aamodt A, Nordsletten L. Customised femoral stems in osteopetrosis and the development of a guiding system for the preparation of an intramedullary cavity: a report of two cases. J Bone Joint Surg Br 2010;92:1303. 8. Lombardi AV, Berend KR, Adams JB. Patient-specific approach in total knee arthroplasty. Orthopedics 2008;31: 927. 9. de Palma L, Tulli A, Maccauro G, et al. Fracture callus in osteopetrosis. Clin Orthop Relat Res 1994;308:85. 10. Strickland JP, Berry DJ. Total joint arthroplasty in patients with osteopetrosis: a report of 5 cases and review of the literature. J Arthroplasty 2005;20:815. 11. Matsuno T, Katayama N. Osteopetrosis and total hip arthroplasty. Report of two cases. Int Orthop 1997;21:409. 12. Janecki CJ, Nelson CL. Osteoarthritis associated with osteopetrosis treated by total hip replacement arthroplasty. Report of a case. Clevel Clin Q 1971;38:169. 13. Ashby ME. Total hip arthroplasty in osteopetrosis. A report of two cases. Clin Orthop Relat Res 1992;214. 14. Girard J, Vendittoli PA, Lavigne M, et al. Resurfacing arthroplasty of the hip in osteopetrosis. J Bone Joint Surg Br 2006;88:818. 15. Casden AM, Jaffe FF, Kastenbaum DM, et al. Osteoarthritis associated with osteopetrosis treated by total knee arthroplasty. Report of a case. Clin Orthop Relat Res 1989; 202.