Use of an Antibiotic Impregnated Polymethyl Methacrylate Intramedullary Spacer for Complicated Revision Total Hip Arthroplasty Matthew
J. K r a a y , M S , M D , V i c t o r M . G o l d b e r g , M D , a n d H a r r y E. F i g g i e I I I , M D
Abstract: Revision total hip arthroplasty is frequently necessary in the presence of significant proximal femoral bone loss, periprosthetic fracture, or infection. In these situations, optimal reconstruction may sometimes warrant the use of special implants, including bone grafts. The emergent presentation of these cases or unexpected findings at the time of surgery can preclude the use of these treatment options. In cases of periprosthetic sepsis, delayed reimplantation may be the most successful approach to eradicate infection. In seven of these complicated revision total hip arthroplasties, the authors used an antibiotic-impregnated intramedullary polymethyl methacrylate spacer with delayed prosthetic reimplantation to allow for the use of these methods. Benefits of this technique include uncompromised radiographic evaluation of the proximal femur for design of a custom implant, if needed, stabilization of the proximal femur facilitating early mobilization of the patient in the case of periprosthetic fracture, and local delivery of antibiotics to the wound in the case of infection. The author's ability to reconstruct these total hip arthroplasties complicated by bone deficiency, fracture, and sepsis, was significantly improved with this use of this technique. Key words: revision hip arthroplasty, polymethyl methacrylate, intramedullary spacer.
Total hip arthroplasty (THA) has proved to be a reliable and generally durable treatment for painful and disabling disorders of the hip. However, this procedure is not without challenging complications. Infection following THA can be difficult to eradicate without removal of the implant and treatment with an extended course of parenteral antibiotics. 3,5,1o Despite this rigorous approach, infection following staged reimplantation occurs all too frequently, and has stimulated interest in adjunctive treatments, including the use of antibiotic-impregnated polymethyl methacrylate (PMMA) beads. ~'2"1~ Frequently, cases of sepsis surrounding a hip prosthesis
are associated with significant b o n e deficits or other related complications, w h i c h m a k e later reconstruction even m o r e difficult. Bone loss surrounding femoral implants in cases of aseptic loosening can pose similar reconstructive problems, especially in the y o u n g patient. In these situations, m a n y authors h a v e advocated cementless revision THA to avoid further b o n e loss associated with the use of cement and to allow reconstitution of proximal femoral b o n e stock. 4'6-8"12 However, periprosthetic fractures can occur t h r o u g h these osteolytic areas before or during surgery and can m a k e revision even m o r e difficult. In aseptic loosening, as well as in other conditions associated with b o n e deficits of the proximal femur, successful reconstruction often requires the use of special implants or extensive b o n e grafting. Unfortu-
From the University Hospitals of Cleveland, Cleveland, Ohio.
Reprint requests: Matthew J. Kraay, MS, MD, UniversityHospitals of Cleveland, 2074 Abington Road, Cleveland, OH 44106.
397
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nately, the unplanned, emergent presentation of complications in some cases (eg, periprosthetic fracture) or unanticipated findings at the time of revision surgery can preclude the use of these treatment options and may compromise the results of the reconstruction. In the case of septic loosening, significant bone deficits are often present following removal of the implant and debridement of the proximal femur. In certain circumstances, we have fabricated an antibiotic-impregnated, intramedullary PMMA spacer that stabilizes and protects the fractured or deficient proximal femur, locally delivers antibiotics in the case of infection, and allows the patient to be mobilized while awaiting later reimplantation. In addition, surgical exposure and preparation of the proximal femur at the time of reimplantation is greatly facilitated with the use of this technique. Radiographic evaluation of the deficient proximal femur for design of a custom prosthesis can easily be accomplished without artifact with the intramedullary spacer in place. In this article we describe our experience with this technique at the University Hospitals of Cleveland.
Materials and Methods An antibiotic-impregnated PMMA spacer was inserted into the medullary canal of the proximal femur in seven hips (7 patients). The patients' records were reviewed retrospectively, and these data form the basis of our report.
Technique Following removal of the prosthesis and debridement of cement debris and pseudomembrane, the PMMA spacer is fabricated and inserted into the proximal femoral canal. Depending on the size of the endosteal cavity, two or three 40-g packages of bone cement are mixed with 2 g of powdered tobramycin. A 16-gauge cerclage wire is then bent back and forth several times to approximate the planned length of the spacer. The wire core serves to reinforce the PMMA spacer and the exposed proximal end of the wire facilitates removal of the spacer at the time of reimplantation. Once the cement has reached the dough state, the cement mass is shaped around the wire to the approximate shape of a cylinder or truncated cone. The doughy cement mass can be inserted into and withdrawn from the proximal canal and shaped by hand to fit the endosteal cavity more closely. After the spacer completely polymerizes outside of the endosteal cavity, it is inserted into the proximal femur. Additional shaping of the spacer to provide optimal fit, which is especially important to
obtain stability in the case of periprosthetic fractures, can be performed with a high-speed pneumatic burr.
Results Of the seven patients, two had septic loosening of a cemented THA and significant associated osteolysis. One of these two patients suffered a fall and subsequent fracture at the level of the midstem of the prosthesis just prior to the planned staged implant removal and delayed reimplantation. At the time of debridement and removal of the implants, extensive comminution at the intertrochanteric and subtrochanteric levels with extensive cortical bone loss was noted. The fracture was reduced and cerdaged around an antibiotic-impregnated rod, which acted as an internal splint to maintain the fragments reduced and aligned. This allowed the patient to be readily mobilized and circumvented the need for traction and prolonged bedrest until his staged reimplantation was performed. After 6 weeks of parenteral antibiotics, the patient's hip was reconstructed with both a segmental allograft and a cemented, long-stemmed prosthesis fixed with antibiotic-impregnated PMMA. The other patient, who had septic loosening and marked osteolysis, suffered a subtrochanteric fracture at the time of attempted hip dislocation during the debridement stage of the planned delayed reimplantation. After debridement, the fracture was internally splinted with an antibiotic-impregnated PMMA rod and the patient was treated with a 6-week course of parenteral antibiotics. Again, sufficient stability at the fracture site was obtained to allow the patient to be mobilized immediately after surgery. Following this, an aspirate of the hip was positive, and a repeat irrigation and debridement with placement of a new PMMA spacer was performed. After an additional 6-week course of i.v. antibiotics, the repeat aspirate was negative. At the time of surgery, the fracture was noted to be nearly healed in slight rotational malalignment (neutral anteversion). The patient was successfully reimplanted, however, with a standard uncemented total hip prosthesis. Two additional patients had recurrent deep infections. One followed irrigation and debridement of an acute infection surrounding a "hybrid" THA and the other followed a primary exchange of a previously infected bipolar hemiarthroplasty. Removal of a well-fixed, PMMA precoated cemented femoral component in one patient required the use of a long, narrow cortical window to allow for disruption of the distal cement-prothesis interface. The other patient had a significant open section defect already
Polymethyl Methacrylate Intramedullary Spacer present in the proximal femur, noted at revision surgery. Following removal of the components and debridement, an antibiotic-impregnated PMMA spacer was placed into the thin cortical shell of the proximal femur. The bone removed for the cortical window was held in place by cerclage sutures and the underlying intramedullary spacer. Both patients received 6 weeks of parenteral antibiotics, followed by 6 weeks of appropriate oral antibiotics, and were mobilized immediately after surgery without difficulty. Successful reimplantation with a cemented femoral component and antibiotic bone cement was performed in both cases. One 54-year-old patient with a broken femoral stem was noted to have significant proximal femoral bone loss and a fracture of the proximal medial femoral cortex at the time of revision surgery. Because of failure to obtain satisfactory stability with a standard uncemented implant, a delayed reimplantation with a custom femoral component was planned. The fractured fragment was cerclaged in place around an antibiotic-impregnated PMMA spacer and a computerized tomography scan of the involved hip was obtained after surgery, for the design of a custom uncemented femoral component. At the time of reimplantation, the femur was readily exposed and prepared for the uncemented custom component. Successful reimplantation with the custom, uncemented implant was performed without difficulty. One 40-year-old patient with ankylosing spondylitis and extensive osteolysis around a cemented femoral c o m p o n e n t suffered a minimally displaced but comminuted periprosthetic fracture after a fall (Fig. 1). Cultures and pathologic specimens taken at the time of c o m p o n e n t removal and debridement later failed to demonstrate infection surrounding the implant. Because of this patient's young age and the osteolysis associated with his previous cemented THA, revision with a custom, uncemented prosthesis was planned. The fracture fragments were accurately reduced and internally fixed with cerclage wires around an antibiotic-impregnated PMMA spacer, which served as an intramedullary splint (Fig. 2). The patient was mobilized after surgery without difficulty, and a CT scan was obtained for design of a custom prosthesis. While awaiting design and manufacture of the implant, the patient remained ambulatory with crutches and non-weight bearing. Reduction and alignment of the fracture was wellmaintained with this technique until reimplantation with the custom device was performed 10 weeks later (Figs. 3, 4). Excellent fit and stability of the implant was achieved at the time of surgery. The last patient had persistent pain in the right hip following uncemented revision THA. Aspiration of
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Fig. 1. Periprosthetic fracture surrounding a cemented THA in a 40-year-old patient with ankylosing spondylitis and significant osteolysis. Significant fracture comminution was noted at the time of surgery.
the painful hip demonstrated Staphylococcus epidermidis and the implant was subsequently removed. Although no significant bone deficit was present following debridement, a spacer was placed to provide local antibiotics to the wound. The patient was eventually reimplanted without difficulty. At an average follow-up period of 15 months after reimplantation; there were no recurrences of deep infection in any patient. All periprosthetic fractures healed. No patient required any additional surgery on the involved hip following revision. There were no complications attributable to the use of this technique.
Discussion Bone deficits associated with aseptic or septic loosening, or following removal of a total hip prosthesis for other reasons, is a frequently encountered problem complicating revision hip surgery. In m a n y situations, satisfactory reconstruction with the standard armamentarium of implants and methods can be achieved. In certain circumstances, however, the extent of bone loss, presence of an unstable periprosthetic fracture, or premature failure of a cemented prosthesis in a young patient m a y best be managed with the use of special implants or techniques. Because of the unanticipated occurrence of these corn-
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Fig. 2. (A) Anteroposterior and (B) lateral radiographs of the hip following removal of components and debridement of the wound. The comminuted fracture fragments were reduced and cerclage-wired in place around the PMMA spacer, which maintained reduction and alignment.
Fig. 3. Anteroposterior radiograph of the same patient shortly following reimplantation with an uncemented custom femoral component. Note the maintenance of alignment and reduction of the fracture.
plicated situations, many of these therapeutic options may not be readily available at the time of surgery. Rather than risk potential compromise of the results of these reconstructions, we have used the technique described above as a temporizing measure until optimal treatment with special implants or techniques can be implemented. In patients with infection associated with a prosthetic implant, we have generally preferred the staged debridement and delayed reimplantation approach. In this situation, insertion of the PMMA spacer described above serves to deliver antibiotic locally to the wound. Occasionally, intraoperative findings may suggest infection despite negative preoperative aspiration. In this situation, debridement and placement of an antibiotic spacer can be performed and prosthetic insertion delayed until final culture and pathology results are obtained. Regardless of the situation, this technique offers several potential advantages. Radiographic imaging of the proximal femur with the PMMA spacer in place, for design of a custom prosthesis, can be accomplished without difficulty. We feel that the availability of an optimally fit uncemented prosthesis, which often can be obtained only by design of a custom implant, is advantageous in revision THA in the face of femoral deficiency and previous failure of cemented implants in young patients. Obviously, this potential advantage must be weighed against the disadvantage of an additional surgical procedure on the involved hip.
Polymethyl Methacrylate Intramedullary Spacer
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Fig. 4. (A) Anteroposterior and (B) lateral radiographs of the same patient 6 weeks following reimplantation. Note healing of the fracture.
Typically following implant removal from the hip, the "joint space" becomes obliterated by dense fibrous scar tissue, which must be excised at the time of reimplantation. Presence of the spacer in the femoral canal at the time of reimplantation can serve as a landmark guiding the safe exposure of the proximal femur. Placement of a hemispheric acetabular cement spacer, which we have also concurrently used on two occasions, also helps in this regard. Preparation of the proximal femur for insertion of the femoral component is also facilitated with use of this technique by preventing fibrous tissue ingrowth into the canal and maintaining reduction of any fracture fragments. We have not had any difficulties with removal of the spacer at the time of reimplantation, presumably because the cement is allowed to polymerize before final insertion into the femur. In the case of a periprosthetic fracture, delayed reimplantation would normally require treatment with traction or some other type of immobilization until special implants were made available. With use of the intramedullary spacer technique described above, we have been able to mobilize the patients immediately after surgery without difficulty. Configuration of the fracture and fit of the spacer within the proximal femur are important factors influencing adequacy and maintenance of fracture reduction and alignment. Maintenance of reduction and alignment of the fractures facilitated later reimplantation in our patients treated with this technique. Control of rotational alignment with this technique is probably less
secure than axial alignment, as one would expect, even with a femoral implant. Unless taken into account in the design of the femoral component, this could potentially complicate reimplantation if complete healing of the fracture occurred in a malrotated position. Krackow et al. have reported a technique in which PMMA spacers in the acetabulum and proximal femur serve to maintain fascial planes and prevent soft tissue contracture following staged revision THA. 9 Although their technique does not provide for intramedullary splinting of periprosthetic fractures, the authors felt that surgical exposure at the time of reimplantation was facilitated with the use of this method. In the case of septic loosening and deep infection following THA, most recent studies would support such a staged approach to this problem with delayed reimplantation. 3,5,zoIn these situations, antibiotic incorporation into the PMMA spacer described above provides an adjunct to the standard parenteral antibiotic regimen. The spacer may also protect the often thin, fragile shell of cortical bone remaining after removal of the implant while the patient awaits reimplantation. Release of antibiotics from the PMMA, and thus local tissue antibiotic levels and efficacy, deteriorates over a variable period of time in vitro and in vivo. ~~ When local tissue levels of antibiotics decrease sufficiently, such that antibacterial activity is absent, the PMMA spacer may act as a large foreign body and become secondarily infected. For this rea-
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son, we do not r e c o m m e n d using this technique w h e n reimplantation is to be delayed more than 3 - 4 months after implant removal. Obviously, reconstruction of most failed hip arthroplasties can be satisfactorily accomplished without the use of this technique. Patients treated with this technique typically had complex or extensive femoral deficiencies, complicated by the presence of a periprosthetic fracture or sepsis. In certain situations involving bone deficiency or complications related to bone deficiency (eg, periprosthetic fracture) or aseptic or septic loosening, the above-described technique can be useful in optimizing the results of treatment. The use of an antibiotic-impregnated intramedullary spacer in the proximal femur m a y also improve the results of treatment in cases of periprosthetic infection.
4.
5.
6.
7.
8.
9.
References I. Buchholz HW, Elson RA, Engelbrecht E et al: Management of deep infection of total hip replacement. J Bone Joint Surg 63B:342, 1981 2. Buchholz HW, Elson RA, Heinert K: Antibiotic-loaded acrylic bone cement: current concepts. Clin Orthop 190:96, 1984 3. Canner GC, Steinberg ME, Heppenstall RB, Balderson
10.
1i.
12.
R: The infected hip after total hip arthroplasty. J Bone Joint Surg 66A:1393, 1984 Engh CA, Glassman AH, Griffin WL, Mayer JG: Resuits of cementless revision for failed cemented total hip arthroplasty. Clin Orthop 235:91, 1988 Gristina AG, Kolkin J: Current concepts review: total joint replacement and sepsis. J Bone Joint Surg 65A: 128, 1983 Gustilo RB, Pastemak HS: Revision total hip arthroplasty with titanium ingrowth prosthesis and bone grafting for failed cemented femoral component loosening. Clin Orthop 235:111, 1988 Hedley AK, Gruen TA, Ruoff DP: Revision of failed total hip arthroplasties with uncemented rorouscoated anatomic components. Clin Orthop 235:75, 1988 Hungerford DS, Jones LC: The rationale of cementless revision of cemented arthroplasty failures. Clin Orthop 235:12, 1988 Krackow KA, Cohn BT, Eschenroeder HC Jr: Preservation of fascial planes and soft tissue tension in revision joint surgery. Orthopedics 11:803, I988 McDonald DJ, Fitzgerald RH, Ilstrup DM: Two-stage reconstruction of a total hip arthroplasty because of infection. J Bone Joint Surg 71A:828, 1989 Trippel SB: Current concepts review: antibiotic-impregnated cement in total joint arthroplasty. J Bone Joint Surg 68A:1297, 1986 Wilson PD Jr: Revision total hip arthroplasty: current role of polymethylmethacrylate. Clin Orthop 225:218, 1987
J. K r a a y , M S , M D , V i c t o r M . G o l d b e r g , M D , a n d H a r r y E. F i g g i e I I I , M D
Abstract: Revision total hip arthroplasty is frequently necessary in the presence of significant proximal femoral bone loss, periprosthetic fracture, or infection. In these situations, optimal reconstruction may sometimes warrant the use of special implants, including bone grafts. The emergent presentation of these cases or unexpected findings at the time of surgery can preclude the use of these treatment options. In cases of periprosthetic sepsis, delayed reimplantation may be the most successful approach to eradicate infection. In seven of these complicated revision total hip arthroplasties, the authors used an antibiotic-impregnated intramedullary polymethyl methacrylate spacer with delayed prosthetic reimplantation to allow for the use of these methods. Benefits of this technique include uncompromised radiographic evaluation of the proximal femur for design of a custom implant, if needed, stabilization of the proximal femur facilitating early mobilization of the patient in the case of periprosthetic fracture, and local delivery of antibiotics to the wound in the case of infection. The author's ability to reconstruct these total hip arthroplasties complicated by bone deficiency, fracture, and sepsis, was significantly improved with this use of this technique. Key words: revision hip arthroplasty, polymethyl methacrylate, intramedullary spacer.
Total hip arthroplasty (THA) has proved to be a reliable and generally durable treatment for painful and disabling disorders of the hip. However, this procedure is not without challenging complications. Infection following THA can be difficult to eradicate without removal of the implant and treatment with an extended course of parenteral antibiotics. 3,5,1o Despite this rigorous approach, infection following staged reimplantation occurs all too frequently, and has stimulated interest in adjunctive treatments, including the use of antibiotic-impregnated polymethyl methacrylate (PMMA) beads. ~'2"1~ Frequently, cases of sepsis surrounding a hip prosthesis
are associated with significant b o n e deficits or other related complications, w h i c h m a k e later reconstruction even m o r e difficult. Bone loss surrounding femoral implants in cases of aseptic loosening can pose similar reconstructive problems, especially in the y o u n g patient. In these situations, m a n y authors h a v e advocated cementless revision THA to avoid further b o n e loss associated with the use of cement and to allow reconstitution of proximal femoral b o n e stock. 4'6-8"12 However, periprosthetic fractures can occur t h r o u g h these osteolytic areas before or during surgery and can m a k e revision even m o r e difficult. In aseptic loosening, as well as in other conditions associated with b o n e deficits of the proximal femur, successful reconstruction often requires the use of special implants or extensive b o n e grafting. Unfortu-
From the University Hospitals of Cleveland, Cleveland, Ohio.
Reprint requests: Matthew J. Kraay, MS, MD, UniversityHospitals of Cleveland, 2074 Abington Road, Cleveland, OH 44106.
397
398
The Journal of Arthroplasty Vol. 7 Supplement 1992
nately, the unplanned, emergent presentation of complications in some cases (eg, periprosthetic fracture) or unanticipated findings at the time of revision surgery can preclude the use of these treatment options and may compromise the results of the reconstruction. In the case of septic loosening, significant bone deficits are often present following removal of the implant and debridement of the proximal femur. In certain circumstances, we have fabricated an antibiotic-impregnated, intramedullary PMMA spacer that stabilizes and protects the fractured or deficient proximal femur, locally delivers antibiotics in the case of infection, and allows the patient to be mobilized while awaiting later reimplantation. In addition, surgical exposure and preparation of the proximal femur at the time of reimplantation is greatly facilitated with the use of this technique. Radiographic evaluation of the deficient proximal femur for design of a custom prosthesis can easily be accomplished without artifact with the intramedullary spacer in place. In this article we describe our experience with this technique at the University Hospitals of Cleveland.
Materials and Methods An antibiotic-impregnated PMMA spacer was inserted into the medullary canal of the proximal femur in seven hips (7 patients). The patients' records were reviewed retrospectively, and these data form the basis of our report.
Technique Following removal of the prosthesis and debridement of cement debris and pseudomembrane, the PMMA spacer is fabricated and inserted into the proximal femoral canal. Depending on the size of the endosteal cavity, two or three 40-g packages of bone cement are mixed with 2 g of powdered tobramycin. A 16-gauge cerclage wire is then bent back and forth several times to approximate the planned length of the spacer. The wire core serves to reinforce the PMMA spacer and the exposed proximal end of the wire facilitates removal of the spacer at the time of reimplantation. Once the cement has reached the dough state, the cement mass is shaped around the wire to the approximate shape of a cylinder or truncated cone. The doughy cement mass can be inserted into and withdrawn from the proximal canal and shaped by hand to fit the endosteal cavity more closely. After the spacer completely polymerizes outside of the endosteal cavity, it is inserted into the proximal femur. Additional shaping of the spacer to provide optimal fit, which is especially important to
obtain stability in the case of periprosthetic fractures, can be performed with a high-speed pneumatic burr.
Results Of the seven patients, two had septic loosening of a cemented THA and significant associated osteolysis. One of these two patients suffered a fall and subsequent fracture at the level of the midstem of the prosthesis just prior to the planned staged implant removal and delayed reimplantation. At the time of debridement and removal of the implants, extensive comminution at the intertrochanteric and subtrochanteric levels with extensive cortical bone loss was noted. The fracture was reduced and cerdaged around an antibiotic-impregnated rod, which acted as an internal splint to maintain the fragments reduced and aligned. This allowed the patient to be readily mobilized and circumvented the need for traction and prolonged bedrest until his staged reimplantation was performed. After 6 weeks of parenteral antibiotics, the patient's hip was reconstructed with both a segmental allograft and a cemented, long-stemmed prosthesis fixed with antibiotic-impregnated PMMA. The other patient, who had septic loosening and marked osteolysis, suffered a subtrochanteric fracture at the time of attempted hip dislocation during the debridement stage of the planned delayed reimplantation. After debridement, the fracture was internally splinted with an antibiotic-impregnated PMMA rod and the patient was treated with a 6-week course of parenteral antibiotics. Again, sufficient stability at the fracture site was obtained to allow the patient to be mobilized immediately after surgery. Following this, an aspirate of the hip was positive, and a repeat irrigation and debridement with placement of a new PMMA spacer was performed. After an additional 6-week course of i.v. antibiotics, the repeat aspirate was negative. At the time of surgery, the fracture was noted to be nearly healed in slight rotational malalignment (neutral anteversion). The patient was successfully reimplanted, however, with a standard uncemented total hip prosthesis. Two additional patients had recurrent deep infections. One followed irrigation and debridement of an acute infection surrounding a "hybrid" THA and the other followed a primary exchange of a previously infected bipolar hemiarthroplasty. Removal of a well-fixed, PMMA precoated cemented femoral component in one patient required the use of a long, narrow cortical window to allow for disruption of the distal cement-prothesis interface. The other patient had a significant open section defect already
Polymethyl Methacrylate Intramedullary Spacer present in the proximal femur, noted at revision surgery. Following removal of the components and debridement, an antibiotic-impregnated PMMA spacer was placed into the thin cortical shell of the proximal femur. The bone removed for the cortical window was held in place by cerclage sutures and the underlying intramedullary spacer. Both patients received 6 weeks of parenteral antibiotics, followed by 6 weeks of appropriate oral antibiotics, and were mobilized immediately after surgery without difficulty. Successful reimplantation with a cemented femoral component and antibiotic bone cement was performed in both cases. One 54-year-old patient with a broken femoral stem was noted to have significant proximal femoral bone loss and a fracture of the proximal medial femoral cortex at the time of revision surgery. Because of failure to obtain satisfactory stability with a standard uncemented implant, a delayed reimplantation with a custom femoral component was planned. The fractured fragment was cerclaged in place around an antibiotic-impregnated PMMA spacer and a computerized tomography scan of the involved hip was obtained after surgery, for the design of a custom uncemented femoral component. At the time of reimplantation, the femur was readily exposed and prepared for the uncemented custom component. Successful reimplantation with the custom, uncemented implant was performed without difficulty. One 40-year-old patient with ankylosing spondylitis and extensive osteolysis around a cemented femoral c o m p o n e n t suffered a minimally displaced but comminuted periprosthetic fracture after a fall (Fig. 1). Cultures and pathologic specimens taken at the time of c o m p o n e n t removal and debridement later failed to demonstrate infection surrounding the implant. Because of this patient's young age and the osteolysis associated with his previous cemented THA, revision with a custom, uncemented prosthesis was planned. The fracture fragments were accurately reduced and internally fixed with cerclage wires around an antibiotic-impregnated PMMA spacer, which served as an intramedullary splint (Fig. 2). The patient was mobilized after surgery without difficulty, and a CT scan was obtained for design of a custom prosthesis. While awaiting design and manufacture of the implant, the patient remained ambulatory with crutches and non-weight bearing. Reduction and alignment of the fracture was wellmaintained with this technique until reimplantation with the custom device was performed 10 weeks later (Figs. 3, 4). Excellent fit and stability of the implant was achieved at the time of surgery. The last patient had persistent pain in the right hip following uncemented revision THA. Aspiration of
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Fig. 1. Periprosthetic fracture surrounding a cemented THA in a 40-year-old patient with ankylosing spondylitis and significant osteolysis. Significant fracture comminution was noted at the time of surgery.
the painful hip demonstrated Staphylococcus epidermidis and the implant was subsequently removed. Although no significant bone deficit was present following debridement, a spacer was placed to provide local antibiotics to the wound. The patient was eventually reimplanted without difficulty. At an average follow-up period of 15 months after reimplantation; there were no recurrences of deep infection in any patient. All periprosthetic fractures healed. No patient required any additional surgery on the involved hip following revision. There were no complications attributable to the use of this technique.
Discussion Bone deficits associated with aseptic or septic loosening, or following removal of a total hip prosthesis for other reasons, is a frequently encountered problem complicating revision hip surgery. In m a n y situations, satisfactory reconstruction with the standard armamentarium of implants and methods can be achieved. In certain circumstances, however, the extent of bone loss, presence of an unstable periprosthetic fracture, or premature failure of a cemented prosthesis in a young patient m a y best be managed with the use of special implants or techniques. Because of the unanticipated occurrence of these corn-
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Fig. 2. (A) Anteroposterior and (B) lateral radiographs of the hip following removal of components and debridement of the wound. The comminuted fracture fragments were reduced and cerclage-wired in place around the PMMA spacer, which maintained reduction and alignment.
Fig. 3. Anteroposterior radiograph of the same patient shortly following reimplantation with an uncemented custom femoral component. Note the maintenance of alignment and reduction of the fracture.
plicated situations, many of these therapeutic options may not be readily available at the time of surgery. Rather than risk potential compromise of the results of these reconstructions, we have used the technique described above as a temporizing measure until optimal treatment with special implants or techniques can be implemented. In patients with infection associated with a prosthetic implant, we have generally preferred the staged debridement and delayed reimplantation approach. In this situation, insertion of the PMMA spacer described above serves to deliver antibiotic locally to the wound. Occasionally, intraoperative findings may suggest infection despite negative preoperative aspiration. In this situation, debridement and placement of an antibiotic spacer can be performed and prosthetic insertion delayed until final culture and pathology results are obtained. Regardless of the situation, this technique offers several potential advantages. Radiographic imaging of the proximal femur with the PMMA spacer in place, for design of a custom prosthesis, can be accomplished without difficulty. We feel that the availability of an optimally fit uncemented prosthesis, which often can be obtained only by design of a custom implant, is advantageous in revision THA in the face of femoral deficiency and previous failure of cemented implants in young patients. Obviously, this potential advantage must be weighed against the disadvantage of an additional surgical procedure on the involved hip.
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Fig. 4. (A) Anteroposterior and (B) lateral radiographs of the same patient 6 weeks following reimplantation. Note healing of the fracture.
Typically following implant removal from the hip, the "joint space" becomes obliterated by dense fibrous scar tissue, which must be excised at the time of reimplantation. Presence of the spacer in the femoral canal at the time of reimplantation can serve as a landmark guiding the safe exposure of the proximal femur. Placement of a hemispheric acetabular cement spacer, which we have also concurrently used on two occasions, also helps in this regard. Preparation of the proximal femur for insertion of the femoral component is also facilitated with use of this technique by preventing fibrous tissue ingrowth into the canal and maintaining reduction of any fracture fragments. We have not had any difficulties with removal of the spacer at the time of reimplantation, presumably because the cement is allowed to polymerize before final insertion into the femur. In the case of a periprosthetic fracture, delayed reimplantation would normally require treatment with traction or some other type of immobilization until special implants were made available. With use of the intramedullary spacer technique described above, we have been able to mobilize the patients immediately after surgery without difficulty. Configuration of the fracture and fit of the spacer within the proximal femur are important factors influencing adequacy and maintenance of fracture reduction and alignment. Maintenance of reduction and alignment of the fractures facilitated later reimplantation in our patients treated with this technique. Control of rotational alignment with this technique is probably less
secure than axial alignment, as one would expect, even with a femoral implant. Unless taken into account in the design of the femoral component, this could potentially complicate reimplantation if complete healing of the fracture occurred in a malrotated position. Krackow et al. have reported a technique in which PMMA spacers in the acetabulum and proximal femur serve to maintain fascial planes and prevent soft tissue contracture following staged revision THA. 9 Although their technique does not provide for intramedullary splinting of periprosthetic fractures, the authors felt that surgical exposure at the time of reimplantation was facilitated with the use of this method. In the case of septic loosening and deep infection following THA, most recent studies would support such a staged approach to this problem with delayed reimplantation. 3,5,zoIn these situations, antibiotic incorporation into the PMMA spacer described above provides an adjunct to the standard parenteral antibiotic regimen. The spacer may also protect the often thin, fragile shell of cortical bone remaining after removal of the implant while the patient awaits reimplantation. Release of antibiotics from the PMMA, and thus local tissue antibiotic levels and efficacy, deteriorates over a variable period of time in vitro and in vivo. ~~ When local tissue levels of antibiotics decrease sufficiently, such that antibacterial activity is absent, the PMMA spacer may act as a large foreign body and become secondarily infected. For this rea-
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son, we do not r e c o m m e n d using this technique w h e n reimplantation is to be delayed more than 3 - 4 months after implant removal. Obviously, reconstruction of most failed hip arthroplasties can be satisfactorily accomplished without the use of this technique. Patients treated with this technique typically had complex or extensive femoral deficiencies, complicated by the presence of a periprosthetic fracture or sepsis. In certain situations involving bone deficiency or complications related to bone deficiency (eg, periprosthetic fracture) or aseptic or septic loosening, the above-described technique can be useful in optimizing the results of treatment. The use of an antibiotic-impregnated intramedullary spacer in the proximal femur m a y also improve the results of treatment in cases of periprosthetic infection.
4.
5.
6.
7.
8.
9.
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