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J Am Acad Orthop Surg, Vol 16, No suppl_1, July 2008, S86-S93.
© 2008 the American Academy of Orthopaedic Surgeons
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How do alternative bearing surfaces influence wear behavior?

Ian C. Clarke, PhD and Michael T. Manley, PhD

Dr. Clarke is Professor in Research, Peterson Research Center, Loma Linda University, Loma Linda, CA. Dr. Manley is Academic Director, Homer Stryker Center, Mahwah, NJ.

*The Implant Wear Symposium 2007 Engineering Work Group included Donald L. Bartel, PhD, Thomas D. Brown, PhD, Ian C. Clarke, PhD, Roy D. Crowninshield, PhD, Darryl D’Lima, MD, PhD, A. Seth Greenwald, DPhil(Oxon), Steven M. Kurtz, PhD, Jack Lemons, PhD, Michael T. Manley, PhD, Harry A. McKellop, PhD, Orhun K. Muratoglu, PhD, Ebru Oral, PhD, Lisa Pruitt, PhD, Clare Rimnac, PhD, Peter S. Walker, PhD, and Timothy Wright, PhD.

Dr. Clarke or a member of his immediate family has received research or institutional support from Amedica, Biomet, CeramTec, Encore, Global, Smith & Nephew, Stryker, and Zimmer, and has received miscellaneous nonincome support from Biomet, Encore, and Stryker. Dr. Manley or a member of his immediate family has received research or institutional support from Stryker Orthopaedics, holds stock or stock options in Stryker, and is an employee of Stryker Orthopaedics.


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Metal, ceramic, and polyethylene liners represent contemporary bearing choices for total joint replacement. Each has limitations in terms of design, sensitivity to manufacturing, and surgical placement. With polyethylene, larger femoral heads represent a design restriction and a potential wear issue. One side benefit is that polyethylene does not click, squeak, or create stripe wear. The attraction of hard-on-hard bearings (metal-on-metal, ceramic-on-ceramic) is that their typically ultra-low wear alleviates concerns with large femoral head designs. However, hard-on-hard bearings produce stripe wear due to the effects of the rigid liner edge. Slight subluxation (microseparation) during swing phase of gait can result in stripe wear on the ball and liner rim. In addition, high levels of implant wear with vertically placed cups can be anticipated. Currently, only alumina-on-alumina bearings can claim virtually no biologic risk. Thus, the role of laboratory studies is to isolate relevant aspects of performance by cup design and to predict the risk-benefit ratios in patients requiring total hip replacement.

Contemporary bearing choices for total hip arthroplasty (THA) include metal, ceramic, and polyethylene (Table 1). Polyethylene bearings evolved from a non–cross-linked material to a moderately cross-linked material and, more recently, to a highly cross-linked material.1 For ceramics, the alumina-on-polyethylene bearings appear to provide long-term improvement over metal-on-polyethylene bearings.2 Many designs employing ceramic-on-polyethylene bearings have been cleared for use by the US Food and Drug Administration (FDA) and are available with 28- and 32-mm femoral head diameters. Following a confounded manufacturing and clinical experience, an yttria-stabilized zirconia ceramic femoral head was removed from the market around the year 2000.3-5 However, studies continue with the use of magnesia-stabilized zirconia in ceramic-on-polyethylene bearings.6 The alumina-zirconia composite bearing known as BIOLOX delta (CeramTec, Plochingen, Germany) received FDA clearance for use in ceramic-on-polyethylene THA designs with femoral head diameters of up to 36 mm. The BIOLOX forte alumina (CeramTec) used in alumina-on-alumina bearing designs has also received FDA clearance for head diameters of 28 and 32 mm. Two metal-on-metal bearings for hip resurfacing have recently been cleared by the FDA—the Birmingham Hip Replacement (BHR, Smith & Nephew, Memphis, TN) and Cormet (Corin Group, Gloucestershire, UK). A novel ceramic-on-metal bearing combination is currently under investigation in an FDA-monitored study.


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  		Table 1  Comparison of Ceramic-on-Ceramic, Metal-on-Metal, and Ceramic-on–Cross-linked UHMWPE Bearings
 
Each alternative bearing has considerations in terms of its design features and sensitivity to manufacturing variables, surgical technique, patient activity, wear rates, and patient outcomes. As designs and materials evolve, clinical outcomes tend to be snapshots taken in the first decade of use. Thus, long-term risk-benefit ratios are seldom well defined (Figure 1). The role of laboratory wear studies is, therefore, to provide an estimate of future performance to the greatest extent possible in a nonclinical setting. Contemporary wear studies of implant bearings are typically conducted using bovine serum as a joint lubricant, that is, as a surrogate for synovial fluid. In general, such serum data have to be carefully studied for clinical relevance. Although many serum protein artifacts have been uncovered for metal-on-polyethylene and ceramic-on-polyethylene bearings, less is known for the metal-on-metal and ceramic-on-ceramic bearings. Thus, the majority of laboratory wear studies should feature control implants with well-established clinical performance.


Figure 1
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  		Figure 1 Limitations and benefits of contemporary combinations of hip bearings. A, Metal (cobalt-chromium) cup. B, Ceramic cup. C, Ultra-high—molecular-weight polyethylene cup. dia = diameter, THR = total hip replacement

 
Although many parameters influence wear, a basic tenet in tribology is that the harder the surface, the greater the wear resistance. As a ceramic, alumina is the most wear-resistant of all biomaterials.7-9 The much softer titanium alloy was abandoned as a bearing surface in joint arthroplasty due to wear issues.10 Thus, metal-on-metal and ceramic-on-ceramic bearings both offer the potential for higher abrasion resistance than do polyethylene bearings because of their greater resistance to wear. The attractive feature of metal-on-metal and ceramic-on-ceramic bearings is that the lower wear rates may alleviate some concerns relating to use of larger femoral head diameters. With polyethylene bearings, the opposite has held true since publication of the milestone article by Charnley et al11 in 1969; larger head diameters increased polyethylene wear. Polyethylene bearings are often reinforced by metallic acetabular shells (Figure 1, A), which add the negative variables of third-body wear, backside wear, and disassociation between the polyethylene insert and the shell.12-14

The benefit of a polyethylene bearing over a hard-on-hard bearing is that it does not click, squeak, or produce stripe wear. Hard-on-hard bearings have been reported to produce stripe wear due to edge effects in rigid ceramic-on-ceramic THA.15-17 For example, if slight subluxation is possible during the swing phase of gait, the cup edge might create an inferior and somewhat equatorial stripe on the femoral head along with a circumferential stripe along the cup rim.18 During forced reduction at heel-strike, a superior and somewhat equatorial stripe would then be created on the head and the mating cup rim (Figure 2). Such "microseparation" events could result in ceramic debris. In addition, during any impingement event, the destabilizing hip joint forces could produce femoral neck–acetabular cup impingement and additional stripe wear. Thus, ceramic debris could be produced from both the bearing surface of the head and the area where the ceramic interface mates with the metallic femoral trunnion; metallic debris also could be generated at this interface.19 The opposing hip forces might also compress the femoral head against the edge of the cup opposite the impingement site, which could cause formation of a more polar stripe and additional ceramic debris. If a skirted ceramic-on-ceramic head is used, the effect will be to notch the skirt instead of the femoral neck. These additional modes of debris formation raise several impingement issues that may be partly due to design complexity (Figure 3).


Figure 2
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  		Figure 2 Schematic of stripe wear modes with rigid cup rims wearing on the ball counterface and resulting in a wear stripe on the cup bevel. A, With slight subluxation in the swing phase of gait, the cup edge will create an inferior and somewhat equatorial ball stripe. During reduction at heel-strike, a superior but equatorial stripe will be created. Both stripes will produce ceramic-on-ceramic debris. B, At any impingement event, the destabilizing forces will produce a more polar stripe on the ball, and the neck-cup impingement will produce debris from both the metallic femoral neck and the ceramic ball. CoCr = cobalt chromium, Ti-6-4 = grade 5 titanium

 

Figure 3
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  		Figure 3 Possible modes of debris formation with rigid cups (metal-on-metal and ceramic-on-ceramic) that may occur as a result of microseparation, impingement, and dislocation events. CoCr = cobalt chromium, Ti-6-4 = grade 5 titanium, XLPE = cross-linked polyethylene

 
Fortunately, 30 years of clinical experience with metal-on-metal and ceramic-on-ceramic designs has demonstrated that these materials are very resistant to wear unless exceptional clinical conditions are present. Excellent clinical survivorship and lack of osteolysis are reported with hard-on-hard bearing couples.7,16,20,21 Both ceramic-on-ceramic and metal-on-metal couples produce substantially less wear debris than traditional metal-on-polyethylene bearings during congruent articulation.16 Up to 3 mm of linear ceramic wear has been reported on occasion, but only for the one-piece ceramic acetabular components of the 1970s.22 Reports of patients continuing to walk on ceramic cups that were migrating and tilting (1- to 15-year follow-up) were probably related to a combination of inadequate fixation, suboptimal positioning, impingement, and loosening. Thus, these cases represented extreme examples of the stripe wear process. No such reports have occurred since the introduction of modular, metal-backed ceramic cups in the 1990s, and osteolysis appears to be absent. There are examples of rim chipping and other adverse events in some ceramic series. These may reflect cultural differences, for example, squatting and kneeling in Korean patients.23 Stripe wear mapping on both couples with clinical follow-up reveals three prevalent wear types: a primary or habitual wear zone, stripe wear, and transition regions.9,15,19 Thus, hard-on-hard bearings would be expected to provoke stripe wear caused by, for example, microseparation during the swing phase of gait and relocation during heel-strike.

For ceramic-on-ceramic bearings, a prospective, randomized study of 514 THAs in 458 patients (initiated at 16 clinical centers in 1996) examined outcomes with both ceramic-on-ceramic bearings and metal-on-polyethylene controls.7 Small lesions at the resection level of the femoral neck seen on follow-up radiographs were taken to be associated with debris release from the bearing surfaces. Lesions were seen in 3 of 194 (1.5%) ceramic-on-ceramic bearings and in 19 of 95 (20%) metal-on-polyethylene controls (Figure 4). The difference was significant (P = 0.001), as was the superior survivorship of the ceramic-on-ceramic bearings at a more than 5-year follow-up (P = 0.02).


Figure 4
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  		Figure 4 Midterm follow-up of a ceramic-on-ceramic bearing (A) and a ceramic-on-polyethylene bearing (B). A region of reduced radiographic density at the femoral resection level (scalloping) is seen with the polyethylene bearing and is almost certainly a reaction to bearing debris.

 
One unexpected finding from studies of hard-on-hard THA bearings is the occurrence of complications arising from head and liner separation during activity.24 Loss of articular congruency may be caused by neck/cup impingement during flexion in either sitting or stair-rise, in extension at toe-off during gait, or in the swing phase in the presence of loose soft-tissue structures. Damage to the bearing surfaces may occur during impingement or because of edge loading between the head and liner as the head reseats under load.19 In a metal-on-polyethylene bearing, edge loading may not be evident clinically for many years, until wear-through of the polyethylene liner occurs or until the patient presents with osteolysis.

Retrieved hard-on-hard components show evidence of edge loading as a dull, elliptically shaped region on the polished finish of the head and a dull region on the insert rim. These wear stripes are reported for ceramic-on-ceramic19,21,24-26 and metal-on-metal bearings.15 Walter et al,27 in a clinical study of 2,384 ceramic-on-ceramic bearings, noted wear stripes on retrieved components with an incidence of noise of 0.5% (13 hips). The authors concluded that THAs that squeak have too much or too little acetabular anteversion. Other authors suggested that wear stripes are related to implant design,28 metallic particle entrapment, or intraoperative damage during joint reduction.17,19,21 Squeaking of ceramic-on-ceramic bearings always follows some months of clinical use.27 This delayed onset strongly suggests that wear, surface damage, or fluid-film breakdown must occur during use and that some adverse event, such as impingement, subluxation, and/or stripe wear, is a necessary precursor.

A laboratory study has generated ceramic-on-ceramic wear stripes by dragging ceramic heads across the rim of a ceramic liner under load.29 Once a wear stripe formed, audible squeaking occurred with all specimens, whether lubricated or not. The experimental set-up was adjusted so that wear stripes were formed on the femoral head at one of the locations corresponding to damage observed in clinical retrievals. These damaged heads were tested in a joint simulator with bearing couples assigned various wear stripe, clearance, and cup inclination settings. Pristine bearings tested as controls at extremes of manufacturing tolerances did not generate noise. For the damaged heads, certain conditions of load and cup inclination angle routinely developed audible squeaks. Timing of the onset of squeaking occurred during peak compressive load while the wear stripe was in the line of load application and translating along its major axis (Figure 5). Thus, the clinical complication of noise in a small number of ceramic-on-ceramic bearings most likely occurs in the presence of a wear stripe, and formation of a wear stripe requires edge loading between the head and insert. The simulator data suggest that squeaking occurs under specific biomechanical conditions (translation along the wear stripe under load).


Figure 5
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  		Figure 5 Representation of the geometry of a wear stripe on a ceramic-on-ceramic bearing tested in the hip simulator. Squeaking occurred when motion was along the major axis of the stripe when load was applied.

 
Whether or not the severity of squeaking in an already noisy bearing can be moderated by a change in patient biomechanics (eg, shoe lifts or weight reduction) is unknown. The wide variation in the reported proportion of squeaking suggests that variation in surgical technique may also be associated with edge loading and noise. With any rigid cup design, a higher risk of impingement and damage exists,27,30 with accompanying clicking, squeaking, and stripe wear, and a small risk of brittle fracture.31 The latest simulator studies of severe stripe wear demonstrated low wear rates (0.5 to 2 mm3/million cycles) in the clinically relevant range.3,32,33

As with highly cross-linked polyethylene bearings, alumina ceramic bearings have a head diameter limitation. A larger range of femoral head diameters was expected with the high-strength zirconia bearings, but poor clinical experience was linked to an adverse phase transformation within the ceramic material that was not predicted by laboratory models.4,5,32 The introduction of alumina-zirconia composites in the year 2000 now provides more options for ceramic-on-polyethylene and ceramic-on-ceramic bearing combinations. However, clinical data from these ceramic composite bearings are scant at present.

Long-term studies of metal-on-metal bearings have shown good results.34,35 Although geometry/tolerance effects are evident during "run-in," the long-term steady-state wear is very low in simulator studies, ranging close to or <1 mm3/million cycles.36 Short-term, adverse clinical results have been reported in metal-on-metal THA cases; these included lymphocytic reactions, large pseudotumors, and osteolysis.37-39 Such short-term results were unanticipated, given laboratory predictions of very low metal-on-metal wear rates. As with ceramic designs, the rigid metal-on-metal cups may create impingement in some patients that provokes adverse second- and third-body wear effects.40,41 A novel approach is to combine ceramic femoral heads with metal liners. Data now exist from two university laboratories, and the ceramic-on-metal concept is under clinical study around the world.42,43

The role of ceramic-on-ceramic and metal-on-metal bearings continues to be explored, each couple having attendant risks and benefits (Figure 1). One limitation has been that ceramic-on-ceramic, metal-on-metal, and ceramic-on-metal simulator wear studies share limitations in the number of specimens under test (typically a dozen or fewer), large data variations, and no clear reproducibility from one set of tests to another. For example, the initial run-in phase with hard-on-hard bearings dominates the overall wear, and five- to tenfold wear variations are common in apparently identical specimens.44 But how robust are the data? Are the conclusions justified for small test numbers and large data variations? What would happen if the experiment were repeated? Unfortunately, results of such replicate tests have never been published.

Currently, only alumina-on-alumina bearings can claim virtually no biologic risk over 20 to 30 years of clinical use (Figure 1, B). Although ceramic-on-ceramic is the only alternative bearing to demonstrate lack of adverse biology, it has attendant design limitations, is sensitive to surgical placement, and has a small risk of bearing fracture.

Overall, conventional and highly cross-linked polyethylene THA acetabular liners may offer advantages in being more forgiving to insult by third-body wear and lessened (or delayed) clinical consequences of impingement. Metal-on-metal bearings with large head diameters offer the unique clinical advantage of improved motion and stability; however, they may trigger adverse biology in some patients while still sustaining bearing separation in extreme ranges of motion due to bone-on-bone impingement.


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In spite of the many developments in bearing technology, mechanical complications caused by impingement and bearing malpositioning remain a challenge. High levels of implant wear with vertically placed cups are to be expected with all bearing types. Damage caused by femoral neck/acetabular shell impingement may become evident early in some patients with ceramic-on-ceramic and metal-on-metal bearings and as seen in clinical retrievals. Because metal-on-metal wear cannot be detected by standard radiographic means, further work is required using cobalt and chromium ion analyses as a surrogate wear measurement method. Impingement may not be apparent in metal-on-polyethylene bearings until excessive wear leads to osteolysis and revision. In this regard, comparison of titanium ions with cobalt and chromium ion concentrations offers a further diagnostic method. In addition, a better understanding of how to simulate such adverse clinical situations in the laboratory would greatly improve the predictability of performance with each new material and design concept. Understanding the strategies that lead to optimal placement of acetabular implants is another area that could yield rapid improvement in patient satisfaction and implant longevity.

Scant attention has been paid to the effects of stress shielding on the bony structures expected to support acetabular implants in the long term. Densitometry and in vitro studies have demonstrated that stresses in retroacetabular bone following contemporary cup placement are not physiologic.45-47 The effects of bone density changes on the long-term stability of hemispherical acetabular implants are of concern. A recent analytical model predicted that stress shielding of acetabular structures cannot be prevented unless the bearing geometry and the housing geometry are designed to allow flexing of the construct.48 With hip implants now expected to survive for the long term in younger, heavier, and more active patients, preservation of bone stock in the replaced hip will become more important. Prevention of such bone loss may require bearings that are flexible while providing optimal wear resistance. This is another area worthy of investigation.

Finally, the adverse patient reaction to noise from hard-on-hard bearings and its effect on surgical choice has shown that patient acceptance is a design input for development of new bearing materials. The "forgotten" total hip—a construct that allows normal patient activity and normal patient proprioception, minimal adverse bone reaction, and silent operation while at the same time providing a very low-wear bearing—has yet to be developed. Development of soft/soft bearings as a first step to the replacement of articular cartilage itself may also be a worthwhile goal to pursue.


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  1. Dumbleton JH, Manley MT, D’Antonio JA, Capello WN, Wang A: The basis for second-generation highly cross-linked UHMWPE. Clin Orthop Relat Res 2006; 453:265-271. [Medline]
  2. Urban JA, Garvin KL, Boese CK, et al: Ceramic-on-polyethylene bearing surfaces in total hip arthroplasty: Seventeen to twenty-one-year results. J Bone Joint Surg Am 2001; 83:1688-1694. [Abstract/Free Full Text]
  3. Brown SS, Green DD, Pezzotti G, Donaldson TK, Clarke IC: Possible triggers for phase transformation in zirconia hip ball. J Biomed Mater Res B Appl Biomater 2007. [Epub ahead of print]. [Medline]
  4. Clarke IC, Manaka M, Green DD, et al: Current status of zirconia used in total hip implants. J Bone Joint Surg Am 2003; 85 (suppl 4):73-84. [Medline]
  5. Haraguchi K, Sugano N, Nishii T, Miki H, Oka K, Yoshikawa H: Phase transformation of a zirconia ceramic head after total hip arthroplasty. J Bone Joint Surg Br 2001; 83:996-1000. [Medline]
  6. Roy ME, Whiteside LA, Katerberg BJ, Steiger JA: Phase transformation, roughness, and microhardness of artificially aged yttria- and magnesia-stabilized zirconia femoral heads. J Biomed Mater Res A 2007; 83:1096-1102. [Medline]
  7. 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; 441:151-158. [Medline]
  8. Nizard RS, Sedel L, Christel P, Meunier A, Soudry M, Witvoet J: Ten-year survivorship of cemented ceramic-ceramic total hip prosthesis. Clin Orthop Relat Res 1992; 282:53-63. [Medline]
  9. Sedel L, Nizard R, Bizot P, Meunier A: Perspective on a 20-year experience with ceramic-on-ceramic articulation in total hip replacement. Semin Arthroplasty 1998; 9:123.
  10. McGovern TE, Black J, Jacobs JJ, Graham RM, LaBerge M: In vivo wear of Ti6A14V femoral heads: A retrieval study. J Biomed Mater Res 1996; 32:447-457. [ISI][Medline]
  11. Charnley J, Kamangar A, Longfield MD: The optimum size of prosthetic heads in relation to the wear of plastic sockets in total replacement of the hip. Med Biol Eng 1969; 7:31-39. [ISI][Medline]
  12. Collier JP, Mayor MB, Jensen RE, et al: Mechanisms of failure of modular prostheses. Clin Orthop Relat Res 1992; 285:129-139. [Medline]
  13. Kligman M, Furman BD, Padgett DE, Wright TM: Impingement contributes to backside wear and screw-metallic shell fretting in modular acetabular cups. J Arthroplasty 2007; 22:258-264. [ISI][Medline]
  14. McKellop HA: The lexicon of polyethylene wear in artificial joints. Biomaterials 2007; 28:5049-5057. [ISI][Medline]
  15. Dorr LD, Zhinian W, Longjohn DB, Dubois B, Murken R: Total hip arthroplasty with use of the Metasul metal-on-metal articulation: Four to seven-year results. J Bone Joint Surg Am 2000; 82:789-798. [Abstract/Free Full Text]
  16. Huo MH, Parvizi J, Gilbert NF: What’s new in hip arthroplasty. J Bone Joint Surg Am 2006; 88:2100-2113. [Free Full Text]
  17. Walter WL, Lusty PJ, Watson A, et al: Stripe wear and squeaking in ceramic total hip bearings. Semin Arthroplasty 2006; 17:190-195.
  18. Nevelos J, Ingham E, Doyle C, et al: Microseparation of the centers of alumina-alumina artificial hip joints during simulator testing produces clinically relevant wear rates and patterns. J Arthroplasty 2000; 15:793-795. [ISI][Medline]
  19. Walter WL, Insley GM, Walter WK, Tuke MA: Edge loading in third generation alumina ceramic-on-ceramic bearings: Stripe wear. J Arthroplasty 2004; 19:402-413. [ISI][Medline]
  20. 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; 436:164-171. [Medline]
  21. Shishido T, Clarke I, Williams P, et al: Clinical and simulator wear study of alumina ceramic THR to 17 years and beyond. J Biomed Mater Res B Appl Biomater 2003; 67:638-647. [Medline]
  22. Nevelos JE, Ingham E, Doyle C, Nevelos AB, Fisher J: Wear of HIPed and non-HIPed alumina-alumina hip joints under standard and severe simulator testing conditions. Biomaterials 2001; 22:2191-2197. [ISI][Medline]
  23. Yoon TR, Rowe SM, Jung ST, Seon KJ, Maloney WJ: Osteolysis in association with a total hip arthroplasty with ceramic bearing surfaces. J Bone Joint Surg Am 1998; 80:1459-1468. [Abstract/Free Full Text]
  24. Barrack RL, Burak C, Skinner HB: Concerns about ceramics in THA. Clin Orthop Relat Res 2004; 429:73-79. [Medline]
  25. Manaka M, Clarke IC, Yamamoto K, Shishido T, Gustafson A, Imakiire A: Stripe wear rates in alumina THR: Comparison of microseparation simulator study with retrieved implants. J Biomed Mater Res B Appl Biomater 2004; 69:149-157. [Medline]
  26. Shishido T, Yamamoto K, Tanaka S, Masaoka T, Clarke IC, Williams P: A study for a retrieved implant of ceramic-on-ceramic total hip arthroplasty. J Arthroplasty 2006; 21:294-298. [ISI][Medline]
  27. Walter WL, O’Toole GC, Walter WK, Ellis A, Zicat BA: Squeaking in ceramic-on-ceramic hips: The importance of acetabular component orientation. J Arthroplasty 2007; 22:496-503. [ISI][Medline]
  28. Yang CC, Kim RH, Dennis DA: The squeaking hip: A cause for concern-disagrees. Orthopedics 2007; 30:739-742. [ISI][Medline]
  29. Taylor S, Manley M, Sutton K: The role of stripe wear in causing acoustic emissions from alumina ceramic-on-ceramic bearings. J Arthroplasty 2007; 22( 7 suppl 3 ):47-51. [ISI][Medline]
  30. 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. [Medline]
  31. Colwell CWJ, Hozack WJ, Mesko JW, et al: Ceramic-on-ceramic total hip arthroplasty early dislocation rate. Clin Orthop Relat Res 2007; 465:155-158. [Medline]
  32. Clarke IC: Metastable nature of zirconia femoral heads from a 20-year perspective of clinical and simulator wear study. Semin Arthroplasty 2006; 17:165-178.
  33. Green DD, Williams P, Pezzotti G, Clarke IC: Stripe wear analyses in large diameter ceramic-on-ceramic bearings in microseparation simulator mode. Presented at the Society for Biomaterials Annual Meeting, Chicago, Illinois, April 18-21, 2007.
  34. Dorr LD, Long WT: Metal-on-metal: Articulations for the new millennium. Instr Course Lect 2005; 54:177-182. [Medline]
  35. Learmonth ID, Gheduzzi S, Vail TP: Clinical experience with metal-on-metal total joint replacements: Indications and results. Proc Inst Mech Eng [H] 2006; 220:229-237. [ISI][Medline]
  36. Firkins PJ, Tipper JL, Ingham E, Stone MH, Farrar R, Fisher J: Influence of simulator kinematics on the wear of metal-on-metal hip prostheses. Proc Inst Mech Eng [H] 2001; 215:119-121. [ISI][Medline]
  37. Boardman DR, Middleton FR, Kavanagh TG: A benign psoas mass following metal-on-metal resurfacing of the hip. J Bone Joint Surg Br 2006; 88:402-404. [Medline]
  38. Milosev I, Trebse R, Kovack S, Cör A, Pisot V: Survivorship and retrieval analysis of Sikomet metal-on-metal total hip replacements at a mean of seven years. J Bone Joint Surg Am 2006; 88:1173-1182. [Abstract/Free Full Text]
  39. Willert HG, Buchhorn GH, Fayyazi A, et al: Metal-on-metal bearings and hypersensitivity in patients with artificial hip joints: A clinical and histomorphological study. J Bone Joint Surg Am 2005; 87:28-36. [Abstract/Free Full Text]
  40. Cosmi F, Hoglievina M, Fancellu G, Martinelli B: A finite element method comparison of wear in two metal-on-metal total hip prostheses. Proc Inst Mech Eng [H] 2006; 220:871-879. [ISI][Medline]
  41. Passuti N, Terver S: Metal on metal bearing surfaces in total hip arthroplasty: A survey of material incidents. Rev Chir Orthop Reparatrice Appar Mot 2007; 93:288-312. [ISI][Medline]
  42. Brockett C, Williams S, Jin Z, Isaac G, Fisher J: Friction of total hip replacements with different bearings and loading conditions. J Biomed Mater Res B Appl Biomater 2007; 81:508-515. [Medline]
  43. Williams S, Isaac G, Hardaker C, et al: The 2007 Otto Aufranc Award: A comparative in vitro and in vivo study. Clin Orthop Relat Res 2007; 465:23-32.[Medline]
  44. Clarke IC, Donaldson T, Bowsher JG, Nasser S, Takahashi T: Current concepts of metal-on-metal hip resurfacing. Orthop Clin North Am 2005; 36:143-162. [ISI][Medline]
  45. Schmidt R, Muller L, Kress A, Hirschfelder H, Alplas A, Pitto RP: A computed tomography assessment of femoral and acetabular bone changes after total hip arthroplasty. Int Orthop 2002; 26:299-302. [ISI][Medline]
  46. Widmer KH, Zurfluh B, Morscher EW: Load transfer and fixation mode of press-fit acetabular sockets. J Arthroplasty 2002; 17:926-935. [ISI][Medline]
  47. Wright JM, Pellicci PM, Salvati EA, Ghelman B, Roberts MM, Koh JL: Bone density adjacent to press-fit acetabular components: A prospective analysis with quantitative computed tomography. J Bone Joint Surg Am 2001; 83:529-536. [Abstract/Free Full Text]
  48. Manley MT, Ong KL, Kurtz SM: The potential for bone loss in acetabular structures following THA. Clin Orthop Relat Res 2006; 453:246-253. [Medline]




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