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A Novel Technique for the Removal of Well-Fixed Cementless, Large-Diameter Metal-on-Metal Acetabular Components
The Journal of Arthroplasty Vol. 23 No. 7 2008
Technical Note
A Novel Technique for the Removal of Well-Fixed Cementless, Large-Diameter Metal-on-Metal Acetabular Components Christophe Olyslaegers, MD, Tom Wainwright, BSc (Hons) MCSP, and Robert G. Middleton, MA FRCS (Tr &Orth)
Abstract: Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components often leads to acetabular bone loss and compromises reimplantation of a new socket. Instruments like the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) are developed to avoid such issues. We report a novel technique, cementing a polyethylene liner inside the uncemented metal-on-metal shell and using systems such as the Explant to safely extract it without the need for matching large-diameter heads. We successfully used this technique on 3 occasions and recommend its use. Key words: hip resurfacing, acetabular revision, removal of cementless component. © 2008 Elsevier Inc. All rights reserved.
bony ingrowth. Possible indications for application of this technique would include proven deep infection, which requires removal of all components, severe backside osteolysis, and a malpositioned socket with implant or bony impingement and subsequent hip pain. The implant industry has responded accurately to the needs of the revision surgeon and developed instruments such as the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) to overcome such issues with less effort. It was designed to minimize acetabular bone loss at the bone-cup interface and uses 2 blade styles for each cup size to facilitate progressive removal of the cup. The blades closely match the acetabular cup's outer diameter, and centering heads, which match the acetabular cup inner diameter, are used to stabilize and guide the blades during cutting. Well-fixed, medialized sockets should be approached very cautiously so as to avoid damage to the medial wall. However, with large-diameter metal-on-metal (MoM) articulations becoming more popular, removing a well-fixed cementless acetabular component remains a challenge. Matching large-diameter centering heads for
Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components using curved gouges and osteotomes often leads to extended acetabular bone loss and compromises reimplantation of a new socket whether it is cemented or uncemented. The importance of using a more boneconservative technique has been emphasized in the literature [1-4,10], and several techniques have been described to address the difficulty of this task [5-7]. Fortunately, indications for implant removal are scarce, and most of the contemporary cementless components perform very well through improved
From the Orthopaedic Department, The Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Bournemouth, UK. Submitted July 20, 2007; accepted April 8, 2008. No benefits or funds were received in support of the study. Reprint requests: Christophe Olyslaegers, MD, Orthopaedic Department, Royal Bournemouth Hospital, Castle Lane East, Bournemouth, BH7 7DW Dorset, UK. © 2008 Elsevier Inc. All rights reserved. 0883-5403/08/2307-0020$34.00/0 doi:10.1016/j.arth.2008.04.006
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1072 The Journal of Arthroplasty Vol. 23 No. 7 October 2008
Fig. 1. Dissociated Birmingham shell and Palacos cemented Zimmer cemented acetabulum liner.
these components are not as widely available as the more common head sizes. A trial liner could be used, but it would lack stability and spin or move when it is introduced in the polished surface of the MoM articulation. We report a novel technique using a cemented polyethylene liner inside the uncemented shell that facilitates component removal, is quick and easy to use, and reduces acetabular bone loss (Fig. 1).
Fig. 3. Precise fit of the Explant blades around a resurfacing shell.
A default technique is used to dissect the hip joint, and the acetabular component is exposed circum-
ferentially. When implant details are available, the matching-size Explant blades and centering head can be mounted. With this system, sizes ranging from 42 mm up to 72 mm outer diameter can be addressed. All sizes of common heads (22, 26, 28, and 32 mm) can be used, but we recommend using a 32-mm-diameter head. It provides better stability and a bigger pivoting surface. Bone cement is mixed and manually pressurized in its late phase, followed by insertion of a polyethylene liner closely matching the inner diameter of the exposed MoM shell. The
Fig. 2. Polyethylene liner cemented into a resurfacing shell.
Fig. 4. The acetabulum after removal of a resurfacing shell. Well-preserved bone stock and footprint of the shell are clearly visible.
Surgical Technique
Removal of Well-Fixed Cementless Acetabular Components Olyslaegers et al
liner is oriented in the same plane as the receiving socket (Fig. 2). Avoid cement leaking around the circumference of the cementless shell as this will block the Explant blades. We recommend downsizing the polyethylene liner one size because this will facilitate the centering process and it avoids a too big cement mantle. A smaller implant will create an unnecessary thick cement mantle and the central position of the liner is more difficult to control. Positioning a liner eccentrically may cause oversized blades to be used and will potentially remove more bone than necessary. It is therefore important to have a clear view on the entire socket to optimize liner positioning to be able to use blades that will closely match the shells' outer diameter (Fig. 3). For improved stability of the socket-cement interface, the inner surface of the socket can be roughened with a high-speed carbide burr. After cement has set, the liner can then be used as it was the case with a contemporary cementless acetabular component.
Discussion The concept of cementing a polyethylene liner into a metal shell is not a new concept because it has been used as a treatment method in revision hip arthroplasty. Beaule et al [8] used this double-socket technique as an alternative technique when confronted with a deficient locking mechanism or the unavailability of matching liners for a well-fixed uncemented shell. In their article, they reported a 5-year survival rate of 78% with revision as an end point, but they emphasize that this technique should not be used when there is a history of instability. More important, retaining the socket preserves acetabular bone stock and still permits conversion to alternate bearing surfaces [8]. Springer et al [9] reviewed their series and published early results using this technique. They did not see polyethylene dissociation or acetabular loosening and found it to be a successful technique at providing secure fixation while preventing bone loss. We used this technique to remove rather than preserve a wellfixed acetabular component. Removing a well-fixed acetabular component may lead to significant bone loss and subsequently result in a higher incidence of component loosening [10]. Furthermore, MoM arthroplasties are frequently used in the younger patient where preservation of bone stock is of particular importance. In our experience of 3 cases (2 infected and 1 malpositioned resurfacing arthroplasty), with blades closely matching the shell's outer diameter, the implant at time of revision averaged 4 mm
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more than the extracted cup's diameter with a 2-mm press fit (Fig. 4). These results are comparable with the results of articles using the same technique [1] and less than results obtained by conventional methods [11]. Several companies have already developed modular big heads to fit on Explant-like systems, but availability and cost of hiring one of these sets of instruments can be a concern. We found the combination of the Explant Acetabular Cup Removal System and a polyethylene liner cemented inside a large-diameter MoM socket to be technically reproducible, quick, and efficient in preserving host bone. The Explant system is a reliable and safe tool on its own, and we would recommend its use in the revision of well-fixed acetabular components.
References 1. Mitchell PA, Masri BA, Garbuz DS, et al. Removal of well-fixed, cementless, acetabular components in revision hip arthroplasty. J Bone Joint Surg Br 2003;85:949. 2. Blaha JD. Well-fixed acetabular component retention or replacement: the whys and the wherefores. J Arthroplasty 2002;17(4 Suppl 1):157. 3. Gross AE. Restoration of acetabular bone loss 2005. J Arthroplasty 2006;21(4 Suppl 1):117. 4. Burstein G, Yoon P, Saleh KJ. Component removal in revision total hip arthroplasty. Clin Orthop 2004;420:48. 5. Della Valle CJ, Stuchin SA. A novel technique for the removal of well-fixed, porous-coated acetabular components with spike fixation. J Arthroplasty 2001;16:1081. 6. Daum WJ, Calhoun JH. Removal of the acetabular component minimizing destruction of the bone bed. J Arthroplasty 1988;3:379. 7. Markovich GD, Banks SA, Hodge WA. A new technique for removing noncemented acetabular components in revision total hip arthroplasty. Am J Orthop 1999;28:35. 8. Beaule PE, Ebramzadeh E, LeDuff M, et al. Cementing a liner into a stable cementless acetabular shell: the double-socket technique. J Bone Joint Surg Am 2004;86-A:929. 9. Springer BD, Hanssen AD, Lewallen DG. Cementation of an acetabular liner into a well-fixed acetabular shell during revision total hip arthroplasty. J Arthroplasty 2003;18(7 Suppl 1):126. 10. Paprosky W. Treatment of progressive periacetabular osteolysis: cup revision versus liner exchange and bone grafting. Instructional course lecture. 66th Annual Meeting of the American Academy of Orthopaedic Surgeons, February; 1999. 11. Paprosky W, Martin EL. Removal of well-fixed femoral and acetabular components. Am J Orthop 2002;31:476.
Technical Note
A Novel Technique for the Removal of Well-Fixed Cementless, Large-Diameter Metal-on-Metal Acetabular Components Christophe Olyslaegers, MD, Tom Wainwright, BSc (Hons) MCSP, and Robert G. Middleton, MA FRCS (Tr &Orth)
Abstract: Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components often leads to acetabular bone loss and compromises reimplantation of a new socket. Instruments like the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) are developed to avoid such issues. We report a novel technique, cementing a polyethylene liner inside the uncemented metal-on-metal shell and using systems such as the Explant to safely extract it without the need for matching large-diameter heads. We successfully used this technique on 3 occasions and recommend its use. Key words: hip resurfacing, acetabular revision, removal of cementless component. © 2008 Elsevier Inc. All rights reserved.
bony ingrowth. Possible indications for application of this technique would include proven deep infection, which requires removal of all components, severe backside osteolysis, and a malpositioned socket with implant or bony impingement and subsequent hip pain. The implant industry has responded accurately to the needs of the revision surgeon and developed instruments such as the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) to overcome such issues with less effort. It was designed to minimize acetabular bone loss at the bone-cup interface and uses 2 blade styles for each cup size to facilitate progressive removal of the cup. The blades closely match the acetabular cup's outer diameter, and centering heads, which match the acetabular cup inner diameter, are used to stabilize and guide the blades during cutting. Well-fixed, medialized sockets should be approached very cautiously so as to avoid damage to the medial wall. However, with large-diameter metal-on-metal (MoM) articulations becoming more popular, removing a well-fixed cementless acetabular component remains a challenge. Matching large-diameter centering heads for
Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components using curved gouges and osteotomes often leads to extended acetabular bone loss and compromises reimplantation of a new socket whether it is cemented or uncemented. The importance of using a more boneconservative technique has been emphasized in the literature [1-4,10], and several techniques have been described to address the difficulty of this task [5-7]. Fortunately, indications for implant removal are scarce, and most of the contemporary cementless components perform very well through improved
From the Orthopaedic Department, The Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Bournemouth, UK. Submitted July 20, 2007; accepted April 8, 2008. No benefits or funds were received in support of the study. Reprint requests: Christophe Olyslaegers, MD, Orthopaedic Department, Royal Bournemouth Hospital, Castle Lane East, Bournemouth, BH7 7DW Dorset, UK. © 2008 Elsevier Inc. All rights reserved. 0883-5403/08/2307-0020$34.00/0 doi:10.1016/j.arth.2008.04.006
1071
1072 The Journal of Arthroplasty Vol. 23 No. 7 October 2008
Fig. 1. Dissociated Birmingham shell and Palacos cemented Zimmer cemented acetabulum liner.
these components are not as widely available as the more common head sizes. A trial liner could be used, but it would lack stability and spin or move when it is introduced in the polished surface of the MoM articulation. We report a novel technique using a cemented polyethylene liner inside the uncemented shell that facilitates component removal, is quick and easy to use, and reduces acetabular bone loss (Fig. 1).
Fig. 3. Precise fit of the Explant blades around a resurfacing shell.
A default technique is used to dissect the hip joint, and the acetabular component is exposed circum-
ferentially. When implant details are available, the matching-size Explant blades and centering head can be mounted. With this system, sizes ranging from 42 mm up to 72 mm outer diameter can be addressed. All sizes of common heads (22, 26, 28, and 32 mm) can be used, but we recommend using a 32-mm-diameter head. It provides better stability and a bigger pivoting surface. Bone cement is mixed and manually pressurized in its late phase, followed by insertion of a polyethylene liner closely matching the inner diameter of the exposed MoM shell. The
Fig. 2. Polyethylene liner cemented into a resurfacing shell.
Fig. 4. The acetabulum after removal of a resurfacing shell. Well-preserved bone stock and footprint of the shell are clearly visible.
Surgical Technique
Removal of Well-Fixed Cementless Acetabular Components Olyslaegers et al
liner is oriented in the same plane as the receiving socket (Fig. 2). Avoid cement leaking around the circumference of the cementless shell as this will block the Explant blades. We recommend downsizing the polyethylene liner one size because this will facilitate the centering process and it avoids a too big cement mantle. A smaller implant will create an unnecessary thick cement mantle and the central position of the liner is more difficult to control. Positioning a liner eccentrically may cause oversized blades to be used and will potentially remove more bone than necessary. It is therefore important to have a clear view on the entire socket to optimize liner positioning to be able to use blades that will closely match the shells' outer diameter (Fig. 3). For improved stability of the socket-cement interface, the inner surface of the socket can be roughened with a high-speed carbide burr. After cement has set, the liner can then be used as it was the case with a contemporary cementless acetabular component.
Discussion The concept of cementing a polyethylene liner into a metal shell is not a new concept because it has been used as a treatment method in revision hip arthroplasty. Beaule et al [8] used this double-socket technique as an alternative technique when confronted with a deficient locking mechanism or the unavailability of matching liners for a well-fixed uncemented shell. In their article, they reported a 5-year survival rate of 78% with revision as an end point, but they emphasize that this technique should not be used when there is a history of instability. More important, retaining the socket preserves acetabular bone stock and still permits conversion to alternate bearing surfaces [8]. Springer et al [9] reviewed their series and published early results using this technique. They did not see polyethylene dissociation or acetabular loosening and found it to be a successful technique at providing secure fixation while preventing bone loss. We used this technique to remove rather than preserve a wellfixed acetabular component. Removing a well-fixed acetabular component may lead to significant bone loss and subsequently result in a higher incidence of component loosening [10]. Furthermore, MoM arthroplasties are frequently used in the younger patient where preservation of bone stock is of particular importance. In our experience of 3 cases (2 infected and 1 malpositioned resurfacing arthroplasty), with blades closely matching the shell's outer diameter, the implant at time of revision averaged 4 mm
1073
more than the extracted cup's diameter with a 2-mm press fit (Fig. 4). These results are comparable with the results of articles using the same technique [1] and less than results obtained by conventional methods [11]. Several companies have already developed modular big heads to fit on Explant-like systems, but availability and cost of hiring one of these sets of instruments can be a concern. We found the combination of the Explant Acetabular Cup Removal System and a polyethylene liner cemented inside a large-diameter MoM socket to be technically reproducible, quick, and efficient in preserving host bone. The Explant system is a reliable and safe tool on its own, and we would recommend its use in the revision of well-fixed acetabular components.
References 1. Mitchell PA, Masri BA, Garbuz DS, et al. Removal of well-fixed, cementless, acetabular components in revision hip arthroplasty. J Bone Joint Surg Br 2003;85:949. 2. Blaha JD. Well-fixed acetabular component retention or replacement: the whys and the wherefores. J Arthroplasty 2002;17(4 Suppl 1):157. 3. Gross AE. Restoration of acetabular bone loss 2005. J Arthroplasty 2006;21(4 Suppl 1):117. 4. Burstein G, Yoon P, Saleh KJ. Component removal in revision total hip arthroplasty. Clin Orthop 2004;420:48. 5. Della Valle CJ, Stuchin SA. A novel technique for the removal of well-fixed, porous-coated acetabular components with spike fixation. J Arthroplasty 2001;16:1081. 6. Daum WJ, Calhoun JH. Removal of the acetabular component minimizing destruction of the bone bed. J Arthroplasty 1988;3:379. 7. Markovich GD, Banks SA, Hodge WA. A new technique for removing noncemented acetabular components in revision total hip arthroplasty. Am J Orthop 1999;28:35. 8. Beaule PE, Ebramzadeh E, LeDuff M, et al. Cementing a liner into a stable cementless acetabular shell: the double-socket technique. J Bone Joint Surg Am 2004;86-A:929. 9. Springer BD, Hanssen AD, Lewallen DG. Cementation of an acetabular liner into a well-fixed acetabular shell during revision total hip arthroplasty. J Arthroplasty 2003;18(7 Suppl 1):126. 10. Paprosky W. Treatment of progressive periacetabular osteolysis: cup revision versus liner exchange and bone grafting. Instructional course lecture. 66th Annual Meeting of the American Academy of Orthopaedic Surgeons, February; 1999. 11. Paprosky W, Martin EL. Removal of well-fixed femoral and acetabular components. Am J Orthop 2002;31:476.