Healio
Healio
August 01, 2005
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New Technology in Cemented Total Hip Arthroplasty

Abstract

The long-term results of total hip arthroplasty (THA) are predicated by excellent surgical techniques. New technology offers the hope of improving outcomes by providing to surgeons tools that make surgical procedures predictable. Techniques that improve the bone-cement-prosthesis composite should enhance long-term fixation. Less invasive surgical techniques that allow rapid recovery from THA have been recently described. Image-guided surgery may enable surgeons to accurately reconstruct the arthritic hip and improve outcomes.

With >40 years of clinical use, total hip arthroplasty (THA) remains the treatment of choice for end-stage arthrosis of the hip. The evolution of the procedure has continued through that time with various implant and bearing designs, surgical approaches, and fixation options. In many areas of the world, cemented THA remains the procedure of choice with all-polyethylene acetabular cups and metallic stems of various designs. The long-term clinical results continue to support cemented THA as an excellent option for treating degenerative conditions of the hip.1-3

Although excellent long-term results have been reported with cemented THA, early and late complications can occur. Dislocation can be a troublesome complication caused by prosthetic malposition or impingement.4-9 Long-term complications can occur from polyethylene wear including osteolysis and aseptic loosening.10,11 Although some complications are related to the surgical technique, implant design and manufacturing, as well as a variable biologic response, may also contribute to the observed long-term complications. Much research has been dedicated to these issues to identify causes and solutions.

Polymethylmethacrylate

Polymethylmethacrylate (PMMA) has been used for >40 years as a means of primary fixation of cemented hip components. Although PMMA is biocompatible in bulk form, its particulate debris can induce an inflammatory response with granuloma formation and osteolysis.12 The composite created when using PMMA must respect the bone-cement and prosthesis-cement interfaces to maintain long-term fixation. Therefore, care must be taken in each phase of the operative process including bone preparation, cement introduction, and prosthesis insertion. Third-generation cement techniques involve vacuum mixing the cement to remove porosity, irrigation and drying of the femoral canal, plugging the femoral canal to contain the PMMA, and pressurization of the PMMA to force intrusion into the cancellous endosteal bone.13-15

A simple way to improve the prosthesis-cement interface is by preheating the femoral stem to 37° C. This technique has been shown in the laboratory to reduce porosity in the cement and reduce setting times.16

Although the basic chemicals in PMMA have not changed, the composition of monomer, powder, and additives has allowed the customization of the product for different uses. For instance, various brands of PMMA with altered handling characteristics are now available. These can allow variable setting times ranging from 5 to 14 minutes. The viscosity of the cement during the working stage can also now be controlled creating ideal cement-handling properties for different applications. Figure 1 provides an overview of some PMMA brands and their handling characteristics and applications.

Figure 1
Figure 1: Various cement types and their setting characteristics.

The use of antibiotics mixed with cement has been a popular way of delivering high doses of antibiotics to a site of deep infection, including septic total joints.17-20 In the past, this delivery required hand mixing antibiotic powder with the PMMA powder before mixing with the monomer. Polymethylmetha-crylate formulas now exist with premixed antibiotic powder. Although concerns exist about using antibiotic cement in all patients, their selective use in patients who are at an elevated risk of sepsis may be appropriate. Patients at elevated risk include those with rheumatoid arthritis, diabetes, or renal disease, and other immunocompromised patients.

PMMA Delivery

A common method for delivering PMMA to the femoral canal has been with the use of injection guns. The ideal use of this technology includes the delivery of appropriately viscous cement into the femur with a controlled and sustainable pressure.21,22 Temperature and viscosity monitors that can assist the surgeon in injecting the cement at the right time with the right pressure to optimize interdigitation at the bone-cement interface are under development. In addition, cement delivery systems that seal the proximal femur and improve the intramedullary pressure distribution are available.

Bone Preparation

Bone preparation for cemented stem insertion includes transecting the femoral neck, instrumenting the femoral canal, removing blood and debris, and plugging the canal.

The critical elements of these steps are retaining endosteal cancellous bone for PMMA interdigitation, adequately occluding the canal to allow pressurization of the PMMA, and creating a dry bone canal.

Several techniques have been described to occlude the femoral canal prior to cement insertion. These techniques include the use of a bone plug, bone cement, various plastic devices, and most recently bioresorbable plugs.23-26 The latter devices are manufactured from polyactive or polygalactic acid, are available in multiple sizes, and completely dissolve within several weeks of implanting. The author has used >250 Biostop G resorbable plugs (DePuy Orthopaedics, Warsaw, Ind) with cemented femoral stems. In a study of 104 of the Biostop plugs with >2 years’ follow-up, no adverse clinical or radiographic changes occurred and the effectiveness of the plugs at preventing plug migration (80%) or cement escape (94%) was better than the author’s previous experience with nonresorbable plastic devices.

Femoral canal preparation for PMMA insertion can be technically challenging. This is primarily because of the ongoing bleeding that tends to occur within the femoral canal after instrumentation. Hypotensive and/or spinal anesthesia result in a lowered blood pressure, significantly reducing the bleeding and facilitating the cement technique.27,28

Pulsed irrigation systems exist that can facilitate removal of blood and debris, leaving the challenge of drying the canal before cement introduction.29-31 Dry sponges packed into the canal can help in this process, as can negative pressure to suck the fluid out of the canal. The drawback of suction devices is that they tend to suck blood into the femoral canal and occlude the cancellous interstices. A novel technique has been recently introduced whereby carbon dioxide is introduced under pressure to the bone surface to dry the canal (Carbojet CO2 lavage system, Kinamed, Camarillo, Calif). Clinical experience with this technique in the United States is limited, but improved bone-cement interfaces have been reported (personal communication with HM Reynolds, MD).

Cement Mantle

Figure 2
Figure 2: Summit cemented stem (DePuy Orthopaedics) with proximal and distal centralizing PMMA spacers.

In the ideal cemented femoral stem, an even cement mantle surrounds the prosthesis, with the implant positioned in a neutral orientation relative to the femoral axis in both the anteroposterior and lateral planes. Freehand placement of the stem into the canal can lead to malposition and cement mantle defects. The use of centralizing devices has become popular to assist in stem placement (Figures 2 and 3).32-36

The majority of these devices have been PMMA devices that plug into the tip of the stem. Although the devices can improve distal stem position in the femoral canal, a trade off exists. Because of the fluid dynamics during insertion, air bubbles can form around these devices creating potential stress risers in a high-stress region at the tip of the stem.37-41 Devices that improve the flow of PMMA around the centering arms and eliminate stress risers around the stem tip will be advantageous. In addition, proximal centering devices such as PMMA beads can also aid in stem placement and ensure appropriate cement mantle thickness.

Surgical Approach

Minimally invasive surgical approaches to the hip have become popular over the past 2 years.42-44 Much controversy has been generated about the definition and efficacy of these approaches. At this time, minimally invasive implies a smaller incision with less soft tissue dissection than with a standard THA. Four approaches have been described as minimally invasive including single small-incision anterior, anterolateral, or posterolateral approaches, and a two-incision technique.

The small-incision procedures require precise incision placement, creating a “mobile window” that allows access to both the femur and acetabulum. These procedures are basically shortened incisions for a Watson-Jones anterior, modified Hardinge anterolateral, or Gibson posterolateral approach.45-47

The small-incision anterior approach has been reported by Kennon et al48 to offer adequate exposure for THA and maintain the gluteus medius attachment to the trochanter. In this approach, the gluteus medius and minimus are retracted superiorly with the hip dislocated through an anterior arthrotomy. Acetabular preparation is fairly straightforward, whereas femoral preparation requires hip extension and external rotation to gain access to the femoral canal. Care must be taken to protect the gluteus medius muscle during femoral preparation. Kennon has also reported using a second stab incision proximally to allow access to the femoral canal through the gluteus musculature. Curved broaches and handles facilitate canal preparation with this technique.

Figure 3A Figure 3B

Figure 3: Radiographs of Summit cemented stem.

In the case of the anterolateral approach, the anterior one-third of the gluteus medius is released in addition to the gluteus minimus tendon. An anterior capsulotomy allows hip dislocation and access to the acetabulum for reaming and implant insertion. External rotation and elevation of the proximal femur allow standard instrumentation of the femur. Repair of the minimus and medius tendons are required and can be performed with direct suture repair, through drill holes in the trochanter, or with wires if a sliver of trochanteric bone is removed with the tendons attached.

The posterolateral approach involves a small posterolateral incision, with release of only the piriformis and short external rotator muscles. A posterior capsulotomy allows dislocation and subsequent acetabular and femoral bone preparation and implant insertion. Posterior capsular retention and repair is recommended and seems to reduce the incidence of dislocation.49 The capsule and external rotators can be sutured to the trochanter through drill holes placed posterior in the trochanter.

The technical challenges of these two procedures involve bone exposure and preparation. Specially designed retractors and instruments are helpful and can facilitate the procedure. Particularly, acetabular preparation and correct cup placement is more difficult with the minimally invasive posterolateral approach. Curved reamers and cup insertion devices make this part of the procedure much more feasible.

The two-incision approach has been reported by Berger50 to be a new minimally invasive approach to THA. This procedure requires an anterior incision for femoral head removal and acetabular preparation, and a small posterolateral incision for femoral preparation and stem insertion. Fluoroscopy is used to confirm implant placement because visualization is limited. The reported advantage of this technique is the fact that soft tissue dissection is in intramuscular planes and no muscles are cut. A faster recovery is reported and some arthroplasties have been performed as outpatient procedures.

The author has had experience with three approaches (anterolateral, posterolateral, and two-incision) and has found the two-incision technique to be the most challenging. Additionally, because of the limited femoral exposure, implanting a cemented femoral stem through this approach is nearly impossible; less muscle release may speed recovery as all but one of the author’s patients were discharged within 36 hours. However, these patients were preselected and it is unclear how patients’ expectations affected their recovery.

The two-incision technique has a steep learning curve, and increased operating times, surgeon frustration, and blood loss were documented in the author’s institution. Although no complications have occurred in the author’s series, a significant complication rate has occurred at other institutions attempting this procedure.51 Additionally, no randomized controlled series have been performed to demonstrate a clear advantage of the two-incision technique over other techniques.

The small-incision posterolateral appro-ach has allowed similar recovery with shorter operating times and less blood loss, without the need for intraoperative fluoroscopy. Otherwise healthy patients <60 years old have been discharged within 24 hours following a THA with this approach. At this time, no clear clinical difference exists between the small-incision posterolateral group and the two-incision group. Length of stay, time on crutches or cane, and 6-week hip scores have been comparable, whereas operating time and blood loss have been greater for the two-incision technique.

The purpose of smaller incision surgery is to limit soft tissue damage, minimize scarring and blood loss, and facilitate patient recovery from surgery. Although the results are aesthetically pleasing, short-term complications may occur, and the long-term performance of the arthroplasty should not be jeopardized by the use of a small incision. Although modifications in instruments have been made to facilitate the use of a smaller incision, the implants have not changed and bone preparation remains the same. Further research is needed to document appropriate implant placement, short-term complications, and long-term results with minimally invasive techniques.

Image-Guided Surgery

One of the newest techniques in total joint arthroplasty is the use of computer navigation to guide bone preparation and implant placement.52-59 Computer navigation involves the registration of the bony skeleton as points in space, tracked by infrared tracking devices and registered by a computer. Fixed pins with triangular positioned arrays are attached to the pelvis and femur. With arrays attached to the skeleton, the orientation of the acetabulum and proximal femur can be registered and tracked during bone preparation and implant insertion. This technology can provide the surgeon with information that leads to accurate recreation of leg length and hip offset, as well as optimal orientation of the acetabular cup and femoral stem.

Improving implant position may reduce the risk of dislocation, impingement, and premature wear in the arthroplasty. Currently, several software systems are available for hip navigation. Research and development in this field is ongoing and improved software and hardware applications can be expected. Valuable research information on the function and failure mechanisms in THA is likely to lead to even better long-term results in the future.

The coupling of computer navigation and minimally invasive techniques would seem to be a natural evolution in the field of total joint arthroplasty.60 This trend will continue in the future. Surgeons must develop new skills to utilize computers in the operating room. In addition, new teaching methods and surgical instruments must be developed and validated to help surgeons learn these new arthroplasty techniques.

References

  1. Ebramzadeh E, Sarmiento A, McKellop HA, et al. The cement mantle in total hip arthroplasty: analysis of long-term radiographic results. J Bone Joint Surg Am. 1994; 76:77-87.
  2. Ranawat CS, Ranawat AS, Rasquinha VJ. Mastering the art of cemented femoral stem fixation. J Arthroplasty. 2004; 19(Suppl 1):85-91.
  3. Schulte KR, Callaghan JJ, Kelly SS, et al. The outcome of Charnley total hip arthroplasty with cement after a minimum twenty-year
    follow-up. J Bone Joint Surg Am. 1993; 75:961-975.
  4. Barrack RL. Dislocation after total hip arthroplasty: implant design and orientation. Am Acad Orthop Surg. 2003;11:89-99.
  5. Jolles BM, Zangger P, Layvraz P-F. Factors predisposing to dislocation after primary total hip arthroplasty: a multivariate analysis. J Arthroplasty. 2002; 17:282-288.
  6. McCollum DE, Gray WJ. Dislocation after total hip arthroplasty: causes and prevention. Clin Orthop. 1990; 261:159-170
  7. Turner RS. Postoperative total hip prosthetic femoral head dislocations: incidence, etiologic factors, and management. Clin Orthop. 1994; 301:196-204.
  8. Woo RY, Morrey BF. Dislocations after total hip arthroplasty. J Bone Joint Surg Am. 1982; 64:1295-1306.
  9. Woolson ST, Rahimtoola ZO. Risk factors for dislocation during the first 3 months after primary total hip replacement. J Arthroplasty. 1999; 14:662-668.
  10. Howell JR, Blunt LA, Doyle C, et al. In vivo surface wear mechanisms of femoral components of cemented total hip arthroplasties: the influence of wear mechanism of clinical outcome. J Arthroplasty. 2004; 19:88-101.
  11. Star MJ, Colwell CW Jr, Kelman GJ, et al. Suboptimal (thin) distal cement mantle thickness as a contributory factor in total hip arthroplasty femoral component failure. J Arthroplasty. 1994; 9143-149.
  12. Barrack RL, Mulroy R Jr, Harris WH. Improved cementing techniques and femoral component loosening in young patients with hip arthroplasty: a 12 year radiographic review. J Bone Joint Surg Br. 1992; 74:385-389.
  13. Dozier JK, Harrigan T, Kutz WH, Hawkins C. Hill R. Does increased cement pressure produce superior femoral component fixation? J Arthroplasty. 2000; 15:488-495
  14. Noble PC, Collier MB, Maltry JA, et al. Pressurization and centralization enhance the quality and reproducibility of cement mantles. Clin Orthop. 1998; 355:77-89.
  15. Schelling K, Heisel C, Schnurer SM, et al. New PMMA bone cements for vacuum mixing systems. Orthopedics. 2002; 31:556-562.
  16. Iesaka K, Jaffe W, Kummer F. Effects of preheating of hip prostheses on stem-cement interface. J Bone Joint Surg Am. 2003; 85:421-427.
  17. Bourne RB. Prophylactic use of antibiotic bone cement: an emerging standard -- in the affirmative. J Arthroplasty. 2004; 19(Suppl1):73-77.
  18. Bourne RB. Prophylactic use of antibiotic bone cement. J Arthroplasty. 2004; 19(Suppl1);69-72.
  19. Hanssen AD. Prophylactic use of antibiotic bone cement: an emerging standard -- in opposition. J Arthroplasty. 2004; 19(Suppl1):73-77.
  20. Klekamp J, Dawson JM, Haas DW, et al. The use of vancomycin and tobramycin in acrylic bone cement. J Arthroplasty. 1999; 14:339-346.
  21. Dayton MR, Incavo SJ, Churchill DL, et al. Effects of early and late stage cement intrusion into cancellous bone. Clin Orthop. 2002; 405:39-45.
  22. McWilliams TG, Binns MS. The timing of femoral component insertion in cemented hip arthroplasty. J Arthroplasty. 2003; 18:51-55.
  23. Bulstra SK, Geesink RGT, Bakker D, et al. Femoral canal occlusion in total hip replacement using a resorbable and flexible cement restrictor. J Bone Joint Surg Br. 1996; 78:892-898.
  24. Freund KG, Herold N, Rock ND, et al. Poor results with the shuttle stop: resorbable versus non-resorbable intramedullary cement restrictor in a prospective and randomized study with a 2 year follow-up. Acta Orthop Scand. 2003; 74:37-41.
  25. Heisel C, Norman T, Rupp R, et al. In vitro performance of intramedullary cement restrictors in total hip arthroplasty. J Biomech. 2003; 36:835-843.
  26. Oh I, Carlson CE, Tomford W, et al. Improved fixation of the femoral component after total hip replacement using a methylmethacrylate intramedullary plug. J Bone Joint Surg Am. 1978; 60:608-613.
  27. Niemi TT, Pitkanen M, Syrjala M, et al. Comparison of hypotensive epidural anesthesia and spinal anesthesia on blood loss and coagulation during total hip arthroplasty. Acta Anaesthiol Scand. 2000; 44:457-464.
  28. Sharrock NE, Salvati EA. Hypotensive epidural anesthesia for total hip arthroplasty: a review. Acta Orthop Scand. 1996; 67:91-107.
  29. Byrick RJ, Byrick RJ, Bell RS, Kay JC, Waddell JP, Mullen JB. High-volume, high pressure pulsatile lavage during cemented arthroplasty. J Bone Joint Surg Am. 1989; 71:1331-1336.
  30. Christie J, Robinson CM, Singer B, et al. Medullary lavage reduces embolic phenomena and cardiopulmonary changes during cemented hemiarthroplasty. J Bone Joint Surg Br. 1995; 77:456-459.
  31. Morgan J, Holder G, Desoutter G. The measurement and comparison of set characteristics of surgical lavage devices. J Arthroplasty. 2003; 18:45-50.
  32. Berger RA, Seel MJ, Wood MD, et al. Effect of a centralizing device on cement mantle deficiencies and initial prosthetic alignment in total hip arthroplasty. J Arthroplasty. 1997; 12:434-443.
  33. Breusch SJ, Lukoschek M, Kreutzer J, et al. Dependency of cement mantle thickness on femoral stem design and centralizer. J Arthroplasty. 2001; 16:648-657.
  34. Hanson PB, Walker RH. Total hip arthroplasty cemented femoral component distal stem centralizer: effect on stem centralization and cement mantle. J Arthroplasty. 1995; 10:683-688.
  35. Kawate K, Maloney AJ, Bragdon CR, et al. Importance of a thin cement mantle: autopsy studies of eight hips. Clin Orthop. 1998; 355:70-78.
  36. Kawate K, Ohmura T, Nakajima H, et al. Distal cement mantle thickness with a triangular distal centralizer inserted into the stem tip in cemented total hip arthroplasty. J Arthroplasty. 2001; 16:998-1003.
  37. Estok D, Orr T, Harris W. Factors affecting cement strains near the tip of a cemented femoral component. J Arthroplasty. 1997; 12:40-48.
  38. Markolf KL, Amstutz HC. Penetration and flow of acrylic bone cement. Clin Orthop. 1976; 121:99-102.
  39. Murphy BP, Prendergast PJ. The relationship between stress, porosity, and nonlinear damage accumulation in acrylic bone cement. J Biomed Mater Res. 2002; 59:646-654.
  40. Reading AD, McCaskie AW, Barnes MR, et al. A comparison of two modern femoral cementing techniques. J Arthroplasty. 2000; 15:479-487.
  41. Smeds S, Goertzen D, Iverson I. Influence of temperature and vacuum mixing on bone cement properties. Clin Orthop. 1997; 334:326-334.
  42. Hartzband MA. Posterolateral minimal incision for total hip replacement: technique and early results. Orthop Clin North Am. 2004; 35:119-129.
  43. Wenz JF, Gurkan I, Jibodh SR. Mini-incision total hip arthroplasty: a comparative assessment of peri-operative outcomes. Orthopedics. 2002; 25:1031-1043.
  44. Wright JM, Crockett HC, Delgado S, Lyman S, Madsen M, Sculco TP. Mini-incision for total hip arthroplasty: a prospective, controlled investigation with 5-year follow-up evaluation. J Arthroplasty. 2004; 19:538-545.
  45. Hardinge K. The direct lateral approach to the hip. J Bone Joint Surg Br. 1982; 64:17-19.
  46. Moore AT. The Moore self-locking vitallium prosthesis in fresh femoral neck fractures: a new low posterior approach (the southern approach) Instructional. Int Course Lect. 1959; 16:309.
  47. Roberts JM, Fu FH, McClain EJ, et al. A comparison of the posterolateral and anterolateral approaches to total hip arthroplasty. Clin Orthop. 1984; 187:205-210.
  48. Kennon RE, Keggi JM, Wetmore RS, et al. Total hip arthroplasty through a minimally invasive anterior approach. J Bone Joint Surg Am. 2003; 85(Suppl):439-448.
  49. Pellicci PM, Bostrom M, Poss R. Posterior approach to total hip replacement using enhanced posterior soft tissue repair. Clin Orthop. 1998; 355:224-228.
  50. Berger RA. Total hip arthroplasty using the minimally invasive two-incision approach. Clin Orthop. 2003; 417:232-241.
  51. White RE, Archibeck MJ. Learning curve for the two-incision, minimally invasive total hip replacement. Presented at the Hip Society annual meeting. San Francisco, Calif; 2004.
  52. DiGioia AM, Jaramaz B, Blackwell M, et al. Image guided navigation system to measure intraoperatively acetabular implant alignment. Clin Orthop. 1998; 355:8-22.
  53. Haaker RG, Stiehl JB, Stockheim M, et al. Comparison of conventional versus computer assisted acetabular component insertion. Paper No. 31 presented at the American Academy of Orthopaedic Surgeons, San Francisco, Calif; 2004.
  54. Köster G, Willert H-G., Ernstberger T, et al. Centralization of the femoral component in cemented hip arthroplasty using guided stem insertion. Arch Orthop Trauma Surg. 1998; 117:425-429.
  55. Langlotz F. Potential pitfalls of computer aided orthopedic surgery. Injury. 2004; 35:S-A17-S-A23.
  56. Noble PC, Sugano N, Johnston JD, et al. Computer simulation: how can it help the surgeon optimize implant position? Clin Orthop. 2003; 417:242-252.
  57. Nogler M, Rachbauer F, Moyr E, et al. Stem and cup placement in navigated minimally invasive total hip arthroplasty - results of a cadaver study. Soc. Intl. Computer Assisted Orthopaedic Surgery, Chicago, Ill; 2004.
  58. Swank ML. Computer assisted total hip replacement - planning and outcome. Intl. Soc. Computer Assisted Orthopaedic Surgery, Chicago, Ill. 2004
  59. Widmer KH, Grutzner PA. Joint replacement-total hip replacement with CT-based navigation. Injury. 2004; 35(Supp1):S-A84-S-A89.
  60. Wixson RL, MacDonald MD. Imageless computer navigated total hip replacement with a limited posterior approach. Intl. Society for Computer Assisted Orthopaedic Surgery. Chicago, Ill; 2004.

Author

From Methodist Hospital, Clarian Health Care, Indianapolis, Ind.

The author thanks Carol Koetke and Margie LeClaire for their assistance in preparing this manuscript.