By Mark W. Pagnano, MD
Background
Contemporary total hip prostheses with ceramic-on-ceramic, metal-on-metal, or highly cross-linked polyethylene bearing surfaces all appear to be associated with favorable midterm results with regard to wear1. Each bearing surface has a distinct set of advantages and disadvantages and, for that reason, a consensus on the appropriate use of each is unlikely to emerge in the near future. Some surgeons will undoubtedly choose one bearing surface and be comfortable in applying it to all patients. Other surgeons will selectively use each of the bearing surfaces in an effort to balance the pluses and minuses to the clinical circumstance of each patient.
Methods and Clinical Results
In both basic-science bench-testing and early to midterm clinical follow-up, each of the three bearing surfaces (ceramic-on-ceramic, metal-on-metal, or highly cross-linked polyethylene) demonstrates a substantial reduction in wear as compared with the wear that occurs in traditional polyethylene bearing surfaces. The reduction in wear that is seen with highly cross-linked polyethylene is not quite as dramatic as that seen with the hard-on-hard ceramic or metal bearings. Highly cross-linked polyethylene does present some distinct practical advantages over both ceramic and metal, however2. With use of highly cross-linked polyethylene, it is possible to avoid the catastrophic problem of ceramic fracture that can occur with use of ceramic bearings or the marked elevation in serum metal ion levels that can occur with use of metal bearings. Impingement of the hip-stem trunnion against a ceramic or metal articulation is a much higher cause for concern than is impingement of the trunnion against a polyethylene liner. In addition, when cross-linked polyethylene liners are used, surgeons have a much wider array of intraoperative choices with regard to head size (i.e., 28, 32, 36, and 40-mm head sizes), orientation (i.e., 0°, 10°, and 20° of elevation), and offset (standard or lateral offset). Finally, as cost pressures once again reemerge, it should be recognized that cross-linked polyethylene bearings are substantially less expensive than comparable ceramic or metal bearings.
Conclusions and Clinical Relevance
The majority of patients in my total hip practice have their needs met most appropriately with a highly cross-linked polyethylene bearing surface. For very young active women of child-bearing age, a ceramic-on-ceramic bearing has a role. For a subset of very active men, particularly those with posttraumatic arthritis, a metal-on-metal bearing is discussed.
Callaghan JJ, Cuckler JM, Huddleston JI, Galante JO; Implant Wear Symposium 2007 Clinical Work Group. How have alternative bearings (such as metal-on-metal, highly cross-linked polyethylene, and ceramic-on-ceramic) affected the prevention and treatment of osteolysis? J Am Acad Orthop Surg.2008;16 Suppl 1:S33-8.16S33
2008
[PubMed]
Jacobs CA, Christensen CP, Greenwald AS, McKellop H. Clinical performance of highly cross-linked polyethylenes in total hip arthroplasty. J Bone Joint Surg Am.2007;89:2779-86. Erratum in: J Bone Joint Surg Am. 2008;90:628.892779
2007
[CrossRef]
Alumina Ceramic Bearings for Total Hip Arthroplasty: A Ten-Year Experience
By James A. D'Antonio, MD, and Marybeth Naughton, BS
Background
Despite the great success of conventional ultra-high molecular weight polyethylene as a bearing surface for total hip prostheses, wear and resultant osteolysis has become one of the leading causes of failure and reoperation. As an alternative to conventional polyethylene bearings, three other types of bearings have become popular in the past decade: metal on metal, metal or ceramic on highly cross-linked polyethylene, and alumina ceramic on alumina ceramic. Alumina ceramic bearings are attractive because of their extreme hardness and scratch resistance, their hydrophilic nature with improved lubrication, the absence of metal ion release, their far-reduced volumetric wear debris in comparison with other types of bearings, and their superior wear resistance as compared with all other available bearing surfaces1.
Methods
In October 1996, a prospective, controlled, randomized multicenter trial was initiated to compare two ceramic-on-ceramic bearing systems (ABC Systems I and II; Stryker Orthopaedics, Mahwah, New Jersey) with a metal-on-conventional polyethylene bearing system (ABC System III; Stryker Orthopaedics)2. In September 1999, a third ceramic study group (Trident; Stryker Orthopaedics) was added3. Unlike the ceramic acetabular inserts of Systems I and II, the Trident insert was recessed within a titanium sleeve. Five surgeons at five independent sites have followed 475 patients divided among four cohorts (three cohorts received ceramic-on-ceramic bearings and one cohort received the control metal-on-polyethylene bearing). At the time of writing, the length of follow-up is now eleven years for the population that received Systems I, II, or III and nine years for the Trident population. There was no significant difference among the four study groups with regard to preoperative demographics or clinical data at the time of the latest follow-up2,3. The average age of the patients in the four study groups ranged from fifty-two to fifty-five years at the time of implantation.
Clinical Results
Kaplan-Meier survivorship4, with failure defined as revision of either component for any reason as the end point (Figs. 1 and 2), is as follows: the ten-year rate of survivorship of ceramic implants (Systems I and II) was significantly higher than that of the metal-on-polyethylene implants (96.6% and 91.3%, respectively; p = 0.0200). The eight-year rate of survivorship of the Trident implants (97.7%) was also significantly higher than that of the control implants (p = 0.0141). One percent of the patients who received ceramic implants had occasional squeaking of the hip, but this squeaking was considered to be mild and did not result in revision. The only bearing-surface related failures for the ceramic implants (0.5%) were with regard to a liner fracture at six years and an anterior chip fracture that was recognized at nine years. Bearing-surface related failures (2.1%) for the polyethylene control implants were due to osteolysis. Osteolysis was found in 19.4% of the metal-on-polyethylene group and in 1.7% of the ceramic-on-ceramic group. The osteolysis was confined to the proximal femoral resection level in all affected hips.
Conclusions and Clinical Relevance
Increased volumetric wear debris generated at the bearing surface in total hip arthroplasty can lead to osteolysis and a need for reoperation. Ceramic-on-ceramic bearings have superior wear resistance when compared with all other available alternative bearing surfaces, thereby providing an excellent alternative for young and very active patients. With revision for any reason as the end point, we found significantly higher survivorship in hips that received ceramic implants. Only time will determine whether other alternative bearings are equal or superior to ceramic-on-ceramic bearings.
Clarke IC. Role of ceramic implants. Design and clinical success with total hip prosthetic ceramic-to-ceramic bearings. Clin Orthop Relat Res.1992;282:19-30.28219
1992
[PubMed]
D'Antonio J, Capello W, Manley M, Naughton M, Sutton K. Alumina ceramic bearings for total hip arthroplasty: five-year results of a prospective randomized study. Clin Orthop Relat Res.2005;436:164-71.436164
2005
D'Antonio JA, Capello WN, Manley MT, Naughton M, Sutton K. A titanium-encased alumina ceramic bearing for total hip arthroplasty: 3- to 5-year results. Clin Orthop Relat Res.2005;441:151-8.441151
2005
[CrossRef]
Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc.1958;53:457-81.53457
1958
[CrossRef]
Metal-on-Metal Articulations with Large-Diameter Heads
By Adolph V. Lombardi Jr., MD, Keith R. Berend, MD, Michael D. Skeels, DO, and Orlando J. Franchi, MD
With the introduction of alternative bearings in recent years, surgeons have moved from the traditional utilization of 22, 26, 28, and 32-mm heads to the use of larger-diameter heads in total hip arthroplasty. The reported benefits of large femoral heads are enhanced stability secondary to increased range of motion prior to impingement and increased jump distance required for subluxation of the head. It is only with metal-on-metal articulations that femoral heads can be offered in sizes that closely replicate normal anatomy. Following our initial experience with 28 and 32-mm metal-on-metal articulations, we performed a series of total hip arthroplasties with 38-mm metal-on-metal articulations. We have reported our success with this particular device with regard to enhanced stability1,2. In November 2004, a system of large modular head, monoblock shell, metal-on-metal acetabular components was introduced (data on file with manufacturer, Biomet, Inc.). In this system, head sizes range from 38 mm to 60 mm and the acetabular components are 6 mm larger than the femoral head components. As of October 2008, we have used these devices in 886 primary total hip arthroplasties in a total of 786 patients. During eighty-nine randomly selected total hip procedures, the resected femoral head was measured intraoperatively with a caliper by an independent observer. The surgeon was blinded to the measurement and proceeded to complete the arthroplasty according to standard protocol. For the femoral heads that were measured intraoperatively, the femoral head size was restored to within 6 mm larger or smaller than the size of the resected femoral head (average restoration, 0.7 mm larger). To date, there have been no dislocations in this series.
Metal Hypersensitivity Testing in Total Joint Arthroplasty Patients
It has been reported that lymphocytic reactivity to metal may predict poor implant performance or failure in total hip and total knee arthroplasty3. Reports also note an increased prevalence of perivascular lymphocytic infiltration in the soft tissues surrounding failed implants in patients with metal hypersensitivity4.
Serum samples from twenty-one patients who presented to our practice with a painful or failed total joint arthroplasty and from one patient with a painful knee preoperative to surgical intervention were obtained at the time of the office visit and sent for immune response testing at a national laboratory that had a previously validated and published methodology. Arthroplasty types were thirteen metal-on-metal total hip, one metal-on-polyethylene total hip, one ceramic-on-polyethylene total hip, five total knee, and one unicompartmental knee. Capsular tissue from 140 hips undergoing revision total hip arthroplasty at our practice and 137 knees undergoing revision total knee arthroplasty was sent to the pathology laboratory to rule out perivascular lymphocytic infiltration.
Ten (67%) of the fifteen patients with a painful or failed total hip arthroplasty and six (86%) of the seven patients with a painful or failed knee or knee arthroplasty tested positive, but this difference was not significant. Eight (62%) of thirteen patients who had undergone metal-on-metal total hip arthroplasty had positive reactions, which was no different statistically in comparison with the patients with metal-on-polyethylene and ceramic-on-polyethylene articulations. Surgical pathology results revealed a significantly higher number of failed total knee arthroplasties (sixty-five of 137, or 47%) with evidence of perivascular lymphocytic infiltration as compared with the number of failed total hip arthroplasties (forty-six of 140, or 33%; p = 0.0132, Pearson chi-square).
These findings cast a question on the utility of serum metal-sensitivity testing in the diagnosis and management of possible metal hypersensitivity as they show a prevalence of positive results that are similar to those reported for osteoarthritic control patients in previously published papers5. Additionally, findings of perivascular lymphocytic infiltration do not appear to hallmark metal hypersensitivity associated with metal-on-metal total hip arthroplasty, as the prevalence is higher with failed total knee arthroplasty than with failed total hip arthroplasty.
Smith TM, Berend KR, Lombardi AV Jr, Emerson RH Jr, Mallory TH. Metal-on-metal total hip arthroplasty with large heads may prevent early dislocation. Clin Orthop Relat Res.2005;441:137-42.441137
2005
[PubMed][CrossRef]
Cuckler JM, Moore KD, Lombardi AV Jr, McPherson E, Emerson R. Large versus small femoral heads in metal-on-metal total hip arthroplasty. J Arthroplasty.2004;19(8 Suppl 3):41-4.1941
2004
Thomas P, Braathen LR, Dörig M, Auböck J, Nestle F, Werfel T, Willert HG. Increased metal allergy in patients with failed metal-on-metal hip arthroplasty and peri-implant T-lymphocytic inflammation. Allergy. 2009 Feb 12. [Epub ahead of print]
2009
Davies AP, Willert HG, Campbell PA, Learmonth ID, Case CP. An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements. J Bone Joint Surg Am.2005;87:18-27.8718
2005
[CrossRef]
Hallab NJ, Caicedo M, Finnegan A, Jacobs JJ. Th1 type lymphocyte reactivity to metals in patients with total hip arthroplasty. J Orthop Surg Res.2008;3:6.36
2008
[CrossRef]
What Are the Evidence-Based Data for Bearing Surfaces?
By David Backstein, MD
Modern total hip bearing surfaces include metal on metal, ceramic, and highly cross-linked polyethylene. The harder the bearing surface, the greater the wear resistance; therefore, metal-on-metal and ceramic-on-ceramic bearings have the potential to exhibit better wear resistance than polyethylene does.
Highly cross-linked polyethylene studies with greater than four years of follow-up have demonstrated reduced proximal femoral head penetration and wear rates1,2. Studies have shown a 42% to 72% reduction in wear rates for annealed cross-linked polyethylene at two to five years of follow-up1,2. Earlier generations of highly cross-linked polyethylene suffered from fatigue, reduced toughness, and reduced tensile strength. Liner fractures appear to be related to high acetabular abduction angles combined with thin polyethylene.
Studies of alumina ceramic heads on ceramic acetabular components demonstrate excellent long-term wear properties3. Wear has been related to positioning of the cup in <15° of anteversion4. Two primary concerns related to ceramic components have been squeaking and chip fractures and cracks at the rim of the acetabular liners, particularly when the components are malpositioned.
Metal-on-metal designs allow for low wear rates and the use of large heads, which improve stability and range of motion. Concerns related to metal-on-metal components include elevated serum ion concentrations, metal allergy, pseudotumors, osteolysis, and so-called runaway wear related to malpositioned acetabular components.
In summary, all three bearing surfaces (metal on metal, ceramic, and highly cross-linked polyethylene) have demonstrated substantial reductions in wear in comparison with that sustained by traditional polyethylene bearing surfaces, but with potential complications when sockets are malpositioned. Clinical decision-making must take into account not only patient activity level, but tolerance for potential ion elevations, squeaking, and the need for features such as elevated rims or large heads.
Martell JM, Verner JJ, Incavo SJ. Clinical performance of a highly cross-linked polyethylene at two years in total hip arthroplasty: a randomized prospective trial. J Arthroplasty.2003;18(7 Suppl 1):55-9.1855
2003
D'Antonio JA, Manley MT, Capello WN, Bierbaum BE, Ramakrishnan R, Naughton M, Sutton K. Five-year experience with Crossfire highly cross-linked polyethylene. Clin Orthop Relat Res.2005;441:143-50.441143
2005
[PubMed][CrossRef]
Garcia-Cimbrelo E, Garcia-Rey E, Murcia-Mazón A, Blanco-Pozo A, Martí E. Alumina-on-alumina in THA: a multicenter prospective study. Clin Orthop Relat Res.2008;466:309-16.466309
2008
[CrossRef]
Koo KH, Ha YC, Jung WH, Kim SR, Yoo JJ, Kim HJ. Isolated fracture of the ceramic head after third-generation alumina-on-alumina total hip arthroplasty. J Bone Joint Surg Am.2008;90:329-36.90329
2008
[CrossRef]