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The Revision Femur: A Potpourri of Options—Proximal Bone Loss: Distal Modular Fixation
The Revision Femur: A Potpourri of Options—Proximal Bone Loss: Distal Modular Fixation John J. Callaghan, MD,† Steve S. Liu, MD,* and Christopher W. Wells, BA* There are many options in revision total hip arthroplasty with cases of proximal femoral bone loss (Paprosky Type IIB and Type IV femurs). The gold standard has been the use of extensively coated stems with a track record of 90%-95% survivorship at 10 years following revision surgery. Modular tapered stems can address problems that were somewhat problematic with extensively coated stems. Specifically, it is an option in the revision situation where distal diaphyseal fixation is less than 4 cm, in cases of large femoral canals, and in cases with stability concerns (ie, retention of acetabular components). Semin Arthro 21:48-50 © 2010 Elsevier Inc. All rights reserved. KEYWORDS total hip revision, proximal femoral bone loss, modular fixation
T
here are many options in revision total hip arthroplasty with cases of proximal femoral bone loss (Paprosky Type IIB and Type IV femurs).1 The gold standard has been the use of extensively coated stems with a track record of 90%-95% survivorship at 10 years following revision surgery.2,3 The advantages of extensively coated stems are the relative ease of use, versatility, and a proven track record. The potential disadvantages are limited range of anteversion, difficulty with leg length equality, and stability becomes an issue when using larger sizes or in cases of less than 4 cm of diaphyseal fixation. Given the above choices and compromises, extensively coated stems are still my choice in 90%-95% of my femoral revisions. Fluted distal fixation with Wagner type stems have had reports of excellent fixation as well as bone preservation.4-6 Grit blasting promotes bone on growth and mechanical stability was provided by flutes (rotational stability) as well as tapered cones (axial stability). Bohm and Bischel4 have one of the best follow-ups of the Wagner monolithic fluted stems. They reported a 4.7% revision rate at 4.8 year follow-up with 88% restoration of proximal femoral bone. They also reported a 20% subsidence rate. Thus, the potential problems with Wagner stems are that if they were too loose, subsidence could be an issue and if they were too tight, leg length could be a concern.
Distal Modular Fixation
*Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USA. †VA Medical Center, Iowa City, IA, USA. J.J.C. is a Consultant and receives Royalties from DePuy. Address reprint requests to John J. Callaghan, MD, 200 Hawkins Drive, UIHC, 01029 JPP, Iowa City, IA 52242. E-mail: john-callaghan@ uiowa.edu
Indications for Distal Modular Fixation
48
1045-4527/10/$-see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1053/j.sart.2009.12.002
Modular fluted stems can address many of the potential problems with Wagner type stems. The distal taper provides stability, anteversion can be dialed in and the proximal body can address leg length. The advantages of modular tapered fluted stems are relative ease of use (pot the stem distally, put on the proximal piece, and adjust anteversion and length through the modular junctions), versatility, and ability to be used in cases of poor bone stock since less diaphyseal fixation is needed. The potential disadvantages include breakage of tapers, fretting and debris, expense, and risk of anterior perforation (no bow to the prosthesis). The concerns for the modular junction are because these stems are used in cases with little to no proximal bone. Thus, the stems are potted distally without proximal support. Combine that with the extreme bending and rotational loads over millions of cycles (especially in cases of revisions in the young active patient) and it is not difficult to see the reasons for concern. It is important to note that when using fluted grit blasted stems, creating a tapered cone requires the use of straight reamers (I recommend using hand held reamers). Be wary of the risk of anterior perforation due to the anterior femoral bow. Even Wagner would do a more anterior-posterior osteotomy rather than the lateral extended osteotomy.
Periprosthetic fractures are one of the main reasons for using distal modular fixation (Fig. 1). There is less of a concern for fracture of the tapers, especially with older and thinner patients.
Proximal bone loss
49
Figure 1 (A-D) A, and B are prerevision radiographs demonstrating a periprosthetic fracture distal to the tip of the femoral stem. (C, D) demonstrate the same hip revised with a distal modular stem and a constrained liner at 10 months follow-up.
Another indication is in cases of poor diaphyseal bone. It is not always possible to have the critical 4 cm of diaphyseal bone needed for extensively coated stems. The axial loading of the distal modular stems is ideal for these cases. Finally, failures of cementless revisions (nonunions, unstable fibrous ingrowth) are another time to consider distal modular fixation.
Results of Revision Modular Tapered Stems Results of modular tapered stems are promising. Lubinus and Klauser7 reported on the Link MP stem and had no aseptic loosening and no subsidence at 3.5 years follow-up. Sporer and Paprosky8 reported 3% aseptic loosening and 3% radiographic subsidence at minimum 3 year follow-up. At average 45 month follow-up, Rodriguez et al9 reported less than 4% revision and subsidence of 7%.
Conclusions Modular tapered stems can address problems that were somewhat problematic with extensively coated stems. Specifically, it is an option in the revision situation where distal diaphyseal fixation is less than 4 cm, in cases of large femoral canals, and in cases with stability concerns (ie, retention of acetabular components).
References 1. Valle CJ, Paprosky WG: Classification and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. J Bone Joint Surg Am 85:1-6, 2003 (suppl 4) 2. Hamilton WG, Cashen DV, Ho H, et al: Extensively porous-coated stems for femoral revision: A choice for all seasons. J Arthroplasty 22:106-110, 2007 (4 suppl 1) 3. Weeden SH, Paprosky WG: Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty 17:134-137, 2002 (4 suppl 1)
50 4. Bohm P, Bishcel O: Femoral revision with the Wagner SL revision stem. J Bone Joint Surg Am 83:1023-1031, 2001 5. Bohm P, Bischel O: The use of tapered stems for femoral revision surgery. Clin Orthop 420:148-159, 2004 6. Gutierrez Del Alamo J, Garcia-Cimbrelo E, Castellanos V, et al: Radiographic bone regeneration and clinical outcome with the Wagner SL revision stem: A 5-year to 12-year follow-up study. J Arthroplasty 22:515-524, 2007
J.J. Callaghan, S.S. Liu, and C.W. Wells 7. Lubinus P, Klauser W: A modular option for proximal bone loss. Orthopedics 23:953-954, 2000 8. Sporer SM, Paprosky WG: Femoral fixation in the face of considerable bone loss: The use of modular stems. Clin Orthop 429:227-231, 2004 9. Rodriguez JA, Fada R, Murphy SB, et al: Two-year to five-year follow-up of femoral defects in femoral revision treated with the link MP modular stem. J Arthroplasty 24:751-758, 2009
T
here are many options in revision total hip arthroplasty with cases of proximal femoral bone loss (Paprosky Type IIB and Type IV femurs).1 The gold standard has been the use of extensively coated stems with a track record of 90%-95% survivorship at 10 years following revision surgery.2,3 The advantages of extensively coated stems are the relative ease of use, versatility, and a proven track record. The potential disadvantages are limited range of anteversion, difficulty with leg length equality, and stability becomes an issue when using larger sizes or in cases of less than 4 cm of diaphyseal fixation. Given the above choices and compromises, extensively coated stems are still my choice in 90%-95% of my femoral revisions. Fluted distal fixation with Wagner type stems have had reports of excellent fixation as well as bone preservation.4-6 Grit blasting promotes bone on growth and mechanical stability was provided by flutes (rotational stability) as well as tapered cones (axial stability). Bohm and Bischel4 have one of the best follow-ups of the Wagner monolithic fluted stems. They reported a 4.7% revision rate at 4.8 year follow-up with 88% restoration of proximal femoral bone. They also reported a 20% subsidence rate. Thus, the potential problems with Wagner stems are that if they were too loose, subsidence could be an issue and if they were too tight, leg length could be a concern.
Distal Modular Fixation
*Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USA. †VA Medical Center, Iowa City, IA, USA. J.J.C. is a Consultant and receives Royalties from DePuy. Address reprint requests to John J. Callaghan, MD, 200 Hawkins Drive, UIHC, 01029 JPP, Iowa City, IA 52242. E-mail: john-callaghan@ uiowa.edu
Indications for Distal Modular Fixation
48
1045-4527/10/$-see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1053/j.sart.2009.12.002
Modular fluted stems can address many of the potential problems with Wagner type stems. The distal taper provides stability, anteversion can be dialed in and the proximal body can address leg length. The advantages of modular tapered fluted stems are relative ease of use (pot the stem distally, put on the proximal piece, and adjust anteversion and length through the modular junctions), versatility, and ability to be used in cases of poor bone stock since less diaphyseal fixation is needed. The potential disadvantages include breakage of tapers, fretting and debris, expense, and risk of anterior perforation (no bow to the prosthesis). The concerns for the modular junction are because these stems are used in cases with little to no proximal bone. Thus, the stems are potted distally without proximal support. Combine that with the extreme bending and rotational loads over millions of cycles (especially in cases of revisions in the young active patient) and it is not difficult to see the reasons for concern. It is important to note that when using fluted grit blasted stems, creating a tapered cone requires the use of straight reamers (I recommend using hand held reamers). Be wary of the risk of anterior perforation due to the anterior femoral bow. Even Wagner would do a more anterior-posterior osteotomy rather than the lateral extended osteotomy.
Periprosthetic fractures are one of the main reasons for using distal modular fixation (Fig. 1). There is less of a concern for fracture of the tapers, especially with older and thinner patients.
Proximal bone loss
49
Figure 1 (A-D) A, and B are prerevision radiographs demonstrating a periprosthetic fracture distal to the tip of the femoral stem. (C, D) demonstrate the same hip revised with a distal modular stem and a constrained liner at 10 months follow-up.
Another indication is in cases of poor diaphyseal bone. It is not always possible to have the critical 4 cm of diaphyseal bone needed for extensively coated stems. The axial loading of the distal modular stems is ideal for these cases. Finally, failures of cementless revisions (nonunions, unstable fibrous ingrowth) are another time to consider distal modular fixation.
Results of Revision Modular Tapered Stems Results of modular tapered stems are promising. Lubinus and Klauser7 reported on the Link MP stem and had no aseptic loosening and no subsidence at 3.5 years follow-up. Sporer and Paprosky8 reported 3% aseptic loosening and 3% radiographic subsidence at minimum 3 year follow-up. At average 45 month follow-up, Rodriguez et al9 reported less than 4% revision and subsidence of 7%.
Conclusions Modular tapered stems can address problems that were somewhat problematic with extensively coated stems. Specifically, it is an option in the revision situation where distal diaphyseal fixation is less than 4 cm, in cases of large femoral canals, and in cases with stability concerns (ie, retention of acetabular components).
References 1. Valle CJ, Paprosky WG: Classification and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. J Bone Joint Surg Am 85:1-6, 2003 (suppl 4) 2. Hamilton WG, Cashen DV, Ho H, et al: Extensively porous-coated stems for femoral revision: A choice for all seasons. J Arthroplasty 22:106-110, 2007 (4 suppl 1) 3. Weeden SH, Paprosky WG: Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty 17:134-137, 2002 (4 suppl 1)
50 4. Bohm P, Bishcel O: Femoral revision with the Wagner SL revision stem. J Bone Joint Surg Am 83:1023-1031, 2001 5. Bohm P, Bischel O: The use of tapered stems for femoral revision surgery. Clin Orthop 420:148-159, 2004 6. Gutierrez Del Alamo J, Garcia-Cimbrelo E, Castellanos V, et al: Radiographic bone regeneration and clinical outcome with the Wagner SL revision stem: A 5-year to 12-year follow-up study. J Arthroplasty 22:515-524, 2007
J.J. Callaghan, S.S. Liu, and C.W. Wells 7. Lubinus P, Klauser W: A modular option for proximal bone loss. Orthopedics 23:953-954, 2000 8. Sporer SM, Paprosky WG: Femoral fixation in the face of considerable bone loss: The use of modular stems. Clin Orthop 429:227-231, 2004 9. Rodriguez JA, Fada R, Murphy SB, et al: Two-year to five-year follow-up of femoral defects in femoral revision treated with the link MP modular stem. J Arthroplasty 24:751-758, 2009