Evaluation of cementless acetabular component migration

Background Computer-assisted surgery (CAS) for cup placement has been developed to improve the functional results and to reduce the dislocation rate and wear after total hip arthroplasty (THA). Previously published studies demonstrated radiographic benefits of CAS in terms of implant position, but whether these improvements result in clinically important differences that patients might perceive remains largely unknown.Questions/purposes We hypothesized that THA performed with CAS would improve 10-year patient-reported outcomes measured by validated scoring tools, reduce acetabular polyethylene wear as measured using a validated radiological method, and increase survivorship. Methods Sixty patients operated on for a THA between April 2004 and April 2005 were randomized into two groups using either the CAS technique or a conventional technique for cup placement. All patient candidates for a THA with the diagnosis of primary arthritis or avascular necrosis were eligible for the CAS procedure and randomly assigned to the CAS group by the Hospital Informatics Department with use of a systematic sampling method. The patients assigned to the freehand cup placement group were matched for sex, age within 5 years, pathological condition, operatively treated side, and body mass index within 3 points. All patients were operated on through an anterolateral approach (patient in the supine position) using cementless implants. In the CAS group, a specific surgical procedure using an imageless cup positioning computerbased navigation system was performed. There were 16 men and 14 women in each group; mean age was 62 years (range, 24-80 years), and mean body mass index was 25 ± 3 kg/m 2 . No patient was lost to followup at 10 years, but five patients have died (two in the CAS group and three in the control group). At the 10-year followup, an independent observer blinded to the type of technique performed patients' evaluation. Cup positioning was evaluated postoperatively using a CT scan in the two groups with results previously published. At 10 years, we assessed subjective functional outcome and quality of life using validated questionnaires (SF-12, Harris hip score [HHS], Hip injury and Osteoarthritis Outcome Score). Wear rate was then evaluated on standardized radiographs using a previously validated semiautomated computer analogic measurement Each author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any dr...

Section: Methodsmentioning

confidence: 99%

No Benefit After THA Performed With Computer-assisted Cup Placement: 10-year Results of a Randomized Controlled Study

Parratte

Ollivier

Lunebourg

et al. 2016

“…The HXLPE was analyzed using the Martell technique for measuring wear [28]. Radiographs were evaluated for loosening defined as a change in component position of greater than 5 mm or a circumferential radiolucent line of 2 mm or greater [31]. The acetabulum and femur were evaluated for evidence of osteolysis defined as a nonlinear radiolucency greater than 5 mm of the bone adjacent to the prosthesis.…”

Section: Methodsmentioning

confidence: 99%

Low Wear Rates Seen in THAs With Highly Crosslinked Polyethylene at 9 to 14 Years in Patients Younger Than Age 50 Years

Garvin

White

Dusad

et al. 2015

Background Patients 50 years or younger are at high risk for wear-related complications of their total hip arthroplasty (THA) because of their generally higher levels of activity. Highly crosslinked polyethylene (HXLPE) is believed to be more durable for this population than conventional polyethylene because of its improved wear; however, limited information is available on the wear of HXLPE in this population, particularly the wear of HXLPE when it articulates with alternative bearings like Oxinium (Smith & Nephew, Memphis, TN, USA).Questions/purposes The purpose of this study was to evaluate two questions relative to this population of patients undergoing THA. First, what was the linear and volumetric wear rate of HXLPE in patients 50 years or younger at a minimum followup of 9 years and was osteolysis observed in any of these hips? Given the potential for damage to the Oxinium femoral head surface, was the wear of HXLPE in the patients with this material similar to the other bearings or was there accelerated or runaway wear that was visible in any of the patients? Methods From November 1999 to April 2005, 105 THAs were performed in 95 patients 50 years of age or younger (mean, 42 years; range, 20-50 years). The mean body mass index was 30 kg/m 2 (range, 17-51 kg/m 2 ).The mean followup was 12 years (range, 9-14 years). Two patients died, five patients (one bilateral) were lost to followup, and one hip was revised elsewhere for pain. The patients' information was not included in the study, which left 87 patients with 96 hips for analysis. Highly crosslinked polyethylene was the acetabular bearing for all of the hips. We analyzed the linear and volumetric wear of all of the hips using the Martell method. Eighty hips had the same diameter head (28 mm) allowing us to more accurately compare the different bearing materials. The type of femoral head used was related to our sequential use of materials beginning with cobalt chrome (14), ceramic (23) followed by Oxinium (43) in the hips with 28-mm heads. Although cobalt-chrome was used early in this study, our previous experience with ceramic on polyethylene encouraged us to use it as an alternative bearing. The Oxinium was used consecutively for the remaining hips. Results The mean wear of the HXLPE after 1 year of bedding-in (true linear wear)was 0.022 mm/year (95% confidence interval [CI], 0.015-0.030 mm/year). The mean volumetric wear of HXLPE after 1 year of bedding-in (true volumetric wear) was 9 mm 3 /year (95% CI, 4-14 mm 3

“…Definite loosening was defined as acetabular migration of 2 mm or more in the horizontal or vertical direction, with implant rotation or screw breakage. Probable loosening was defined by a radiolucent line greater than 1 mm through all three zones of the acetabulum without migration, rotation, or screw breakage [19]. The grafted bone was considered to be integrated if trabeculae were continuous between the host bone and the grafts, and grafts were considered fully absorbed when the grafted bone visible immediately after surgery no longer was visible [17].…”

Section: Postoperative Recovery and Assessment Of Outcomesmentioning

confidence: 99%

Custom Acetabular Cages Offer Stable Fixation and Improved Hip Scores for Revision THA With Severe Bone Defects

Mao

et al. 2016

Background Revision THA is particularly challenging in hips with severe acetabular bone loss. When the extent or geometry of the acetabular bone loss precludes morestraightforward techniques such as jumbo hemispheric cementless shells, reconstruction with morselized allograft protected by a custom cage may offer an alternative, but, to our knowledge, few series have reported on results with this approach. Questions/purposes For patients with severe (Paprosky IIIB) defects, we asked: do individualized custom cages result in (1) improved Harris hip scores; (2) restoration of hip center; and (3) a low incidence of surgical complications? Methods Twenty-six patients (26 hips) with a massive acetabular defect were involved in this study from 2003 to 2013. During this period, one patient was lost to followup and one died, leaving 24 patients (eight males, 16 females) in this retrospective analysis. The customized cages were individualized to each patient's bone defect based on rapidprototype three-dimensional printed models. Mean followup was 67 months (range, 24-120 months). Harris hip scores were assessed before surgery and at each followup. Postoperative radiographs were evaluated for cage position, migration, and graft incorporation. Complications and reoperations were assessed by chart review. Results The mean Harris hip score improved from 36 (SD,8; range, to 82 (SD, 18; range, 60-96) (p \ 0.001). Individualized custom cages resulted in generally reliable restoration of the hip center. No rerevisions have been performed. None of the cups showed radiographic migration, but one cage was believed to be loose, based on a circumferential 2-mm radiolucent line. Cancellous allografts appeared to be incorporated in 23 of 24 patients. One deep infection and one superficial infection were observed and treated with irrigation, débridement, and vacuumsealing drainage. One dislocation and one suspected injury of the superior gluteal nerve also were observed and treated conservatively. Conclusions Individualized custom cages using rapid prototyping and three-dimensional printing appeared to provide stable fixation and improved hip scores at shortterm followup in this small, single-center series. As further improvements in the design and manufacturing process are made, future studies should evaluate larger patient groups for longer times, and, ideally, compare this approach with alternatives for these complex bone defects.