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Otto Aufranc Award: Crosslinking Reduces THA Wear, Osteolysis, and Revision Rates at 15-year Followup Compared With Noncrosslinked Polyethylene. Clin Orthop Relat Res 2018; 476. [PMID: 29529656 PMCID: PMC6259699 DOI: 10.1007/s11999.0000000000000036] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Crosslinked polyethylene (XLPE) liners used for primary THA have demonstrated lower wear rates than noncrosslinked, conventional polyethylene (CPE) liners through the first decade of clinical service. However, little high-quality evidence is currently available regarding the second decade performance of these implants and it remains uncertain whether the onset of osteolysis has simply been delayed or if the wear associated with XLPE liners will remain low enough that osteolysis will not occur. It is also unknown how the potential reductions in wear and osteolysis will influence long-term revision rates. QUESTIONS/PURPOSES Do patients who underwent THA with XLPE liners demonstrate (1) a lower rate of revision for wear-related complications; (2) a reduced wear rate; and (3) a lower frequency of osteolysis compared with those with CPE liners? METHODS Over an 18-month period from 1999 to 2000, 226 patients who had 236 primary THAs consented to participate in a randomized controlled trial conducted at one institution. To be eligible for intraoperative randomization, patients had to be implanted with a 28-mm cobalt-chrome alloy femoral head, a 4-mm lateralized liner, and the same cup and stem design. Six patients with six THAs were excluded intraoperatively because they did not receive study components for reasons unrelated to the liner material. The remaining 230 THAs among 220 patients were randomized to XLPE liners or CPE liners. The mean age at surgery was 62 ± 11 years and there were no differences in age, gender, or body mass index among the groups. There was no differential loss to followup between the study groups; among patients not known to be deceased or having undergone revision, minimum 14-year radiographic followup is available for 85 THAs including 46 with XLPE and 39 with CPE liners. Polyethylene wear was measured radiographically using Martell's Hip Analysis Suite and areas of osteolysis were evaluated before revision or at most recent followup. Revision rates at 15 years using reoperation for any reason and revision for wear or osteolysis were calculated using cumulative incidence considering patient death as a competing risk. RESULTS The cumulative incidence of revision at 15 years using reoperation for wear-related complications as an endpoint was lower in the XLPE group than the CPE group (0%, 95% confidence interval [CI], 0%-0% versus 12%, 95% CI, 7%-19%; p < 0.001). Among unrevised THAs with minimum 14-year radiographic followup, the mean steady-state linear wear rate for THAs with XLPE liners was lower than the mean linear wear rate for the THAs with CPE liners (0.03 ± 0.05 versus 0.17 ± 0.09 mm/year; mean difference, 0.14; 95% CI, 0.11-0.17; p < 0.001). Osteolysis of any size was noted among 9% (four of 46) of the hips in the XLPE group and 46% (18 of 39) of the hips in the CPE group (odds ratio, 0.19; 95% CI, 0.07-0.51; p < 0.001). CONCLUSIONS This randomized study with followup into the second decade demonstrated reductions in revision, wear, and osteolysis associated with the use of XLPE. The low wear rates and absence of any mechanical failures among the XLPE liners at long-term followup affirm the durability of these components that did not incorporate antioxidants. Although osteolysis has not been eliminated, it occurs infrequently and has not caused any clinical problems to date. LEVEL OF EVIDENCE Level I, therapeutic study.
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Ding L, Gao YH, Li YR, Liu JG, Li SQ, Qi X. Determinants of satisfaction following total hip arthroplasty in patients with ankylosing spondylitis. INTERNATIONAL ORTHOPAEDICS 2017; 42:507-511. [DOI: 10.1007/s00264-017-3589-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/14/2017] [Indexed: 11/24/2022]
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Saglam Y, Ozturk I, Cakmak MF, Ozdemir M, Yazicioglu O. Total hip arthroplasty in patients with ankylosing spondylitis: Midterm radiologic and functional results. ACTA ORTHOPAEDICA ET TRAUMATOLOGICA TURCICA 2016; 50:443-7. [PMID: 27492583 PMCID: PMC6197352 DOI: 10.1016/j.aott.2016.06.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 01/10/2016] [Accepted: 01/24/2016] [Indexed: 02/06/2023]
Abstract
Introduction The aim of this study was to evaluate the clinical and radiological outcomes of total hip arthroplasty (THA) in patients with Ankylosing Spondylitis (AS). Patients and methods One hundred five hips of 61 AS patients (mean age: 41.3 ± 10.2 years) who underwent THA between 1997 and 2012 were included into the study. Dorr's classification of proximal femoral geometry, acetabular protrusio, bone ankylosis, acetabular protrusion, Brooker classification of heterotopic ossification (HO), Gruen and Charnley classifications of implant loosening were used in radiographic assessments. Patients were called back to return for an additional long-term follow-up for functional assessment. Results Cementless total hip arthroplasty was used in 83 hips (79%) and cemented TKA was used in 22 hips (21%). The overall rate of aseptic loosening was 7.6% at a mean follow-up of 5.4 years. Femoral loosening was statistically similar in cemented and cementless femoral components (14% vs. 8%, p = 0.089). Acetabular component loosening was statistically higher in patients with any degree of HO (p = 0.04). Regardless of the type of femoral implant (cemented or cementless), femoral component loosening was higher in Dorr's type C patients (p = 0.005). The average pre-operative HSS was 46.6 ± 16.3, and it improved to 80.7 ± 18.7 at last follow-up (p < 0.01). Conclusion Revision incidence was similar in between ankylosed and non-ankylosed hips. While complication rates are high, significant functional improvement can be achieved after THA in patients with AS.
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Affiliation(s)
- Yavuz Saglam
- Biruni University Hospital, Orthopedics and Traumatology Department, Istanbul, Turkey.
| | - Irfan Ozturk
- Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey
| | - Mehmet Fevzi Cakmak
- Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey
| | - Mustafa Ozdemir
- Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey
| | - Onder Yazicioglu
- Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey
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How Does Wear Rate Compare in Well-functioning Total Hip and Knee Replacements? A Postmortem Polyethylene Liner Study. Clin Orthop Relat Res 2016; 474:1867-75. [PMID: 26891896 PMCID: PMC4925408 DOI: 10.1007/s11999-016-4749-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/10/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND The longevity of total hip (THR) and knee replacements (TKR) that used historical bearing materials of gamma-in-air sterilized UHMWPE was affected more by osteolysis in THRs than in TKRs, although osteolysis remains a concern in TKRs. Therefore, the study of polyethylene wear is still of interest for the knee, particularly because few studies have investigated volumetric material loss in tibial knee inserts. For this study, a unique collection of autopsy-retrieved TKR and THR components that were well-functioning at the time of retrieval was used to compare volumetric wear differences between hip and knee polyethylene components made from identical material. QUESTIONS/PURPOSES The following questions were addressed: (1) How much did the hip liners wear and what wear patterns did they exhibit? (2) How much did the knee inserts wear and what wear patterns did they exhibit? (3) What is the ratio between TKR and THR wear after controlling for implantation time and patient age? METHODS We compared 23 THR components (Harris-Galante [HG] and HG II) and 20 TKR components (Miller-Galante [MG II]) that were retrieved postmortem. The components were made from the same polyethylene formulation and with similar manufacturing and sterilization (gamma-in-air) processes. Twenty-one patients (12 males, nine females) had THRs and 16 (four males, 12 females) had TKRs. Patients who had TKRs had an older (p = 0.001) average age than patients who had THRs (age, 75 years; SD, 10, versus 66 years; SD, 12, respectively). Only well-functioning components were included in this study. Therefore, implants retrieved postmortem from physically active patients and implanted for at least 2 years were considered. In addition, only normally wearing TKR components were considered, ie, those with fatigue wear (delamination) were excluded. The wear volume of each component was measured using metrology. For the tibial inserts an autonomous mathematic reconstruction method was used for quantification. RESULTS The acetabular liners of the THR group had a wear rate of 38 mm(3) per year (95% CI, 29-47 mm(3)/year). Excluding patients with low-activity, the wear rate was 47 mm(3) per year (95% CI, 37-56 mm(3)/year). The wear rate of normally wearing tibial inserts was 17 mm(3) per year (95% CI, -6 to 40 mm(3)/year). After controlling for the relevant confounding variable of age, we found a TKR/THR wear rate ratio of 0.5 (95% CI, 0.29-0.77) at 70 years of age with a slightly increasing difference with increasing age. CONCLUSIONS Excluding delamination, TKRs exhibited lower articular wear rates than THRs for historical polyethylene in these two unique cohorts of postmortem retrievals. CLINICAL RELEVANCE The lower TKR wear rate is in line with the lower incidence of osteolysis in TKRs compared with THRs.
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Noble PC, Durrani SK, Usrey MM, Mathis KB, Bardakos NV. Constrained cups appear incapable of meeting the demands of revision THA. Clin Orthop Relat Res 2012; 470:1907-16. [PMID: 22179979 PMCID: PMC3369098 DOI: 10.1007/s11999-011-2212-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Failure rates of constrained cups for treating recurrent dislocation in revision THA range from 40% to 100%. Although constrained liners are intended to stabilize the hip by mechanically preventing dislocation, the resulting loss of range of motion may lead to impingement and, ultimately, implant failure. QUESTIONS/PURPOSES We therefore documented the mechanisms of failure of constrained acetabular cups in revision THA and determined the type and severity of damage (wear, fracture, and impingement) that occurs in situ. METHODS We retrieved 57 constrained components of four different designs at revision THA and examined for the presence of rim impingement, oxidation, cracks within the liner, backside wear, pitting, scratching, abrasion, burnishing, and the presence of embedded particles. Articular wear was calculated from the volume of the concave articular bearing surface, which was measured using the fluid displacement method. RESULTS Failure of the locking ring was responsible for 51% of failures, whereas 28% of revisions were the result of acetabular cup loosening, 6% backside wear, and 22% infection. Impingement damage of the rim of the polyethylene liner was seen in all retrievals with moderate or severe damage in 54%. The average volumetric wear rate of the articular surface was 95 mm(3)/year. CONCLUSIONS Failure of the locking liner ring and loosening of the acetabular cup are the primary causes of mechanical failure with constrained liners; polyethylene is an inadequate material for restricting motion of the hip to prevent instability. The durability of these devices is unlikely to improve unless the mechanical demands are modified through increased range of motion leading to less frequent rim impingement.
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Affiliation(s)
- Philip C. Noble
- The Institute of Orthopedic Research and Education, Baylor College of Medicine, 6550 Fannin Street, Suite 2501, Houston, TX 77030 USA
- The Methodist Hospital, Houston, TX USA
| | - Salim K. Durrani
- The Institute of Orthopedic Research and Education, 6550 Fannin Street, Suite 2501, Houston, TX 77030 USA
| | - Molly M. Usrey
- The Institute of Orthopedic Research and Education, 6550 Fannin Street, Suite 2501, Houston, TX 77030 USA
| | - Kenneth B. Mathis
- The Methodist Hospital, Houston, TX USA
- Orthopedic Surgery, Weill Cornell Medical College of Cornell University, New York, NY USA
| | - Nikolaos V. Bardakos
- The South West London Elective Orthopaedic Centre, Epsom and St. Helier University Hospitals NHS Trust, Dorking Road, Epsom, KT18 7EG Surrey UK
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Engh CA, Ho H, Powers CC, Huynh C, Beykirch SE, Hopper RH. Osteolysis propensity among bilateral total hip arthroplasty patients. J Arthroplasty 2011; 26:555-61. [PMID: 21575791 DOI: 10.1016/j.arth.2010.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 05/18/2010] [Indexed: 02/01/2023] Open
Abstract
Because some patients with high wear rates demonstrate extensive osteolysis whereas other patients with similarly high wear rates show little or no evidence of osteolysis, we hypothesized that both polyethylene wear and a patient-specific propensity mediate the development of osteolysis. We evaluated wear and osteolysis using computed tomography and radiographs among 46 patients who had undergone bilateral total hip arthroplasties (THAs). A radiographic patient-specific propensity for osteolysis associated with each THA was quantified by dividing the amount of osteolysis by the volumetric wear. Using a multivariate regression analysis to simultaneously consider the influence of polyethylene wear and patient propensity, we found that both factors are associated with the amount of osteolysis around a THA and that they appear to be of similar importance.
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Affiliation(s)
- Charles A Engh
- Anderson Orthopaedic Research Institute, Alexandria, Virginia 22307, USA
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Kampa RJ, Hacker A, Griffiths E, Rosson JW. In vivo polyethylene wear of bilateral total hip replacements - cemented versus uncemented modular sockets. Hip Int 2011; 20:447-52. [PMID: 21157748 DOI: 10.1177/112070001002000406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/19/2010] [Indexed: 02/04/2023]
Abstract
We assessed polyethylene wear and osteolysis in 15 patients (30 hips) undergoing staged bilateral total hip arthroplasties, who had a cemented arthroplasty on one side and a hybrid arthroplasty on the other. All factors apart from mode of acetabular component fixation were matched. Wear was measured radiographically using Livermore's technique. The mean clinical and radiological follow-up was 11.2 years for the cemented and 10.7 years for the hybrid arthroplasties. Mean annual linear wear rate was 0.09mm/year in the cemented sockets and 0.14mm/year in the uncemented sockets. This difference was statistically significant (p=0.03), confirming previous reports that the rate of polyethylene wear is increased in uncemented sockets. No periacetabular osteolysis was noted. Femoral osteolysis in zone 7 occurred in 3 hybrid arthroplasties. It appears not all patients are equally affected. These results are further discussed.
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Affiliation(s)
- Rebecca J Kampa
- Department of Orthopaedics, Royal Surrey County Hospital, Guildford, Surrey, UK.
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Thirion T, Georis P, Gillet P. Migration and wear of the Duraloc "1200 series" cup associated with Enduron UHWMPE using the EBRA method and the Imagika software. Hip Int 2010; 20:198-203. [PMID: 20544643 DOI: 10.1177/112070001002000210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/23/2009] [Indexed: 02/04/2023]
Abstract
We report a retrospective study on 122 THA using Duraloc "1200 series" cups. All patients received a 28-mm head (107 Al2O3, 15 CoCr). The mean age of the patients at surgery was 56.3 years and the mean follow-up was 137 months.Mean migration at two years using the EBRA method was 0.18 mm cranially and 0.16 mm medially. Mean polyethylene wear was 0.03 mm/year using the Imagika software and 0.06 mm/year using EBRA. Only one patient presented with abnormal polyethylene wear of 1.7 mm at 90 months with Imagika and 2.4 mm with EBRA. The Duraloc cup seems to be a reliable implant in respect of bone fixation and resistance to wear.
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Affiliation(s)
- Thierry Thirion
- Orthopaedic Department, University Hospital Sart-Tilman, Liège, Belgium.
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Marks R. Body mass characteristics of hip osteoarthritis patients experiencing aseptic loosening, periprosthetic fractures, dislocation, and infections after total hip replacement. CLINICOECONOMICS AND OUTCOMES RESEARCH 2009; 1:7-16. [PMID: 21935302 PMCID: PMC3169987 DOI: 10.2147/ceor.s4280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Indexed: 01/14/2023] Open
Abstract
This work assessed the body mass characteristics of a cohort of community dwelling adults requiring surgery for complications related to primary hip arthroplasty, among other factors. The specific aim was to identify the extent to which high body mass prevailed in the cohort as a whole, to identify a role for subnormal body mass in the pathogenesis of post-operative complications following hip joint arthroplasty, and to identify whether different complication types could be differentiated on the basis of body mass profiles. The subjects were males and females drawn from a representative sample of 1,040 hip osteoarthritis patients between the ages of 30-89 years hospitalized for purposes of primary hip arthroplasty or complications related to prior replacement surgery. An analysis of their medical records showed: 1) Approximately 20% of the present cohort was constituted by patients with various complications related to prior arthroplasties, or to general deterioration of their condition; 2) The most common reasons for their re-hospitalization were aseptic prosthetic loosening followed by infection, prosthetic dislocations, prosthetic and periprosthetic fractures, and second surgeries on the opposite hip; 3) The presence of a high body mass index differentiated those presenting with aseptic prosthetic loosening, periprosthetic fractures, and those with infected hips (p < 0.007). Those with infection diagnoses were significantly heavier on average than those with no infection, regardless of diagnosis, and more cases with a dislocation history were underweight, rather than overweight (p < 0.05). It is concluded, a small but clinically relevant proportion of obese or underweight adults with hip osteoarthritis who undergo primary total hip replacement may experience complications at higher rates than cases with normal body weight, despite the generally successful outcomes experienced by the majority of hip arthroplasty patients.
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Affiliation(s)
- Ray Marks
- City University of New York and Columbia University, New York, NY, USA
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Heiner AD, Lundberg HJ, Baer TE, Pedersen DR, Callaghan JJ, Brown TD. Effects of episodic subluxation events on third body ingress and embedment in the THA bearing surface. J Biomech 2008; 41:2090-6. [PMID: 18561936 DOI: 10.1016/j.jbiomech.2008.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 04/30/2008] [Accepted: 05/01/2008] [Indexed: 11/25/2022]
Abstract
In total joint arthroplasty, third body particle access to the articulating surfaces results in accelerated wear. Hip joint subluxation is an under-recognized means by which third body particles could potentially enter the otherwise closely conforming articular bearing space. The present study was designed to test the hypothesis that, other factors being equal, even occasional events of femoral head subluxation greatly increase the number of third body particles that enter the bearing space and become embedded in the acetabular liner, as compared to level-walking cycles alone. Ten metal-on-polyethylene hip joint head-liner pairs were tested in a multi-axis joint motion simulator, with CoCrMo third body particles added to the synovial fluid analog. All component pairs were tested for 2h of level walking; half were also subjected to 20 intermittent subluxation events. The number and location of embedded particles on the acetabular liners were then determined. Subluxation dramatically increased the number of third body particles embedded in the acetabular liners, and it considerably increased the amount of scratch damage on the femoral heads. Since both third body particles and subluxation frequently occur in contemporary total hip arthroplasty, their potent synergy needs to be factored prominently into strategies to minimize wear.
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Affiliation(s)
- Anneliese D Heiner
- Department of Orthopaedics and Rehabilitation, Biomechanics Laboratory, University of Iowa, 2181 Westlawn, Iowa City, IA 52242, USA.
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Hamilton WG, Hopper RH, Ginn SD, Hammell NP, Engh CA, Engh CA. The effect of total hip arthroplasty cup design on polyethylene wear rate. J Arthroplasty 2005; 20:63-72. [PMID: 16214005 DOI: 10.1016/j.arth.2005.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Accepted: 05/10/2005] [Indexed: 02/01/2023] Open
Abstract
Using 743 total hip arthroplasties that included 6 hemispheric porous-coated cup designs, this study used a multiple linear regression to identify those factors that influenced polyethylene wear rates. Wear rates for each hip were based on serial head penetration measurement made with computer-assisted techniques. Implant factors associated with an increased wear rate included terminal sterilization with a non-cross-linking chemical surface treatment, a 4-mm lateralized liner, a cobalt-chrome femoral head, and a longer shelf life for liners gamma-irradiated in air. After accounting for these implant characteristics and patient factors, wear rates among the 6 cup designs were not significantly different (P = .89). Although polyethylene wear is frequently characterized for specific implant designs, this study demonstrated that there are several common factors that influence polyethylene wear rates.
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Affiliation(s)
- William G Hamilton
- Anderson Orthopaedic Research Institute, Alexandria, Virginia 22307, USA
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12
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Abstract
This retrospective study evaluated the implant, patient and surgical factors associated with polyethylene wear for one type of porous-coated hemispheric total hip arthroplasty cup. Radiographic wear measurements among 567 Duraloc cups (512 patients) revealed that liners sterilized by gamma-irradiation wore 0.085 mm/year less than those that were sterilized by gas-plasma, a noncross-linking chemical surface treatment. The substantially decreased wear rate associated with gamma-irradiation was attributed to sterilization-induced polyethylene cross-linking. Shelf-aging adversely affected liners that were gamma irradiated in air. On average, highly crystalline Hylamer liners showed a 0.064 mm/year increase in wear rates for each year of shelf storage after terminal sterilization with gamma-irradiation in air. Among conventional Enduron liners, the effect of shelf aging after gamma-irradiation in air was more modest, increasing wear rates by 0.014 mm/year for each year of shelf storage. Because Hylamer's wear performance degraded at about five times the rate of Enduron's, the improved wear resistance associated with gamma-irradiation in air would be lost after 1.3 years of shelf aging for Hylamer compared with 6.1 years for Enduron. For every additional year of age at the time of surgery, the wear rate decreased by 0.003 mm/year. Increased body mass index, a preoperative diagnosis of inflammatory arthritis, and a ceramic femoral head also were associated with decreased wear rates.
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Affiliation(s)
- Robert H Hopper
- Anderson Orthopaedic Research Institute, PO Box 7088, Alexandria, VA 22307, USA.
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14
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Hopper RH, Young AM, Orishimo KF, Engh CA. Effect of terminal sterilization with gas plasma or gamma radiation on wear of polyethylene liners. J Bone Joint Surg Am 2003; 85:464-8. [PMID: 12637432 DOI: 10.2106/00004623-200303000-00010] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Although terminal sterilization with gamma radiation in air promotes cross-linking, which improves wear resistance, it also results in free radicals, which can oxidize and degrade the mechanical properties of polyethylene liners used for total hip arthroplasty. For this reason, non-cross-linked polyethylene components have also been sterilized with chemical surface treatments, such as gas plasma. In this study, we tested the hypothesis that conventional polyethylene liners cross-linked by sterilization with gamma radiation in air had better in vivo wear performance than non-cross-linked liners sterilized with gas plasma. METHODS We retrospectively reviewed the wear rates in a series of hips treated with a Duraloc 100 cup, a 28-mm femoral head, and an Enduron liner that had been sterilized with either gamma radiation (sixty-one hips followed for a mean of 5.2 years) or gas plasma (sixty-three hips followed for a mean of 3.9 years). The irradiated liners had been stored with access to ambient oxygen for an average of 1.0 year (range, 0.05 to 5.72 years) prior to implantation. Multiple linear regression was used to assess the effect of the sterilization method on the wear rate while accounting for the possible influence of other factors, including liner geometry, femoral head material, patient gender, cup abduction angle, and age at surgery. RESULTS The polyethylene liners that had been sterilized with gamma radiation in air had a significantly lower wear rate than did the gas-plasma-sterilized liners (0.097 compared with 0.19 mm/yr, p < 0.001). The sterilization method (p < 0.001) and age at surgery (p = 0.001) were the only factors that we analyzed that correlated with the wear rate. CONCLUSIONS The in vivo wear of conventional polyethylene liners that had been sterilized with gamma radiation in air was, on the average, 50% less than that of non-cross-linked liners sterilized with gas plasma. LEVEL OF EVIDENCE Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence.
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Affiliation(s)
- Robert H Hopper
- Anderson Orthopaedic Research Institute, Alexandria, Virginia 22307, USA.
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Orishimo KF, Sychterz CJ, Hopper RH, Engh CA. Can component and patient factors account for the variance in wear rates among bilateral total hip arthroplasty patients? J Arthroplasty 2003; 18:154-60. [PMID: 12629604 DOI: 10.1054/arth.2003.50023] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The purpose of this study was to indirectly quantify the effect of patient and component factors on polyethylene wear in patients with bilateral hip arthroplasties. Assuming that both hips experience similar levels of activity, the confounding influence of activity on wear can be removed by comparing wear rates within subjects. We studied temporal wear patterns in 21 patients with bilateral hip arthroplasty with a mean follow-up of 102 months. Each patient had matching acetabular cup and femoral head components implanted in both hips. Regression analyses were used to assess the variation in wear rates between the first and second implanted hips. The r(2) value demonstrated that matched components and patient factors accounted for 61% of the variance in wear rates. The remaining 39% of the variance, which is unaccounted for, indicates that factors other than those related to the components and patient also play a role.
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Affiliation(s)
- Karl F Orishimo
- Anderson Orthopaedic Research Institute, Alexandria, Virginia 22306, USA
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