???Modes of Failure??? of Cemented Stem-type Femoral Components

Background Reports in the literature have linked high acetabular inclination angles to increased wear of ceramicon-ceramic bearings. However, many of these studies were only conducted in vitro and did not address the clinical relevance of such findings. Questions/purposes We therefore determined: (1) whether the cup inclination angle influences survival or function in patients with ceramic-on-ceramic implants; (2) the incidence of radiolucencies, osteolysis, and subsidence of ceramic-on-ceramic implants; and (3) whether the survival rate higher for ceramic-on-ceramic THAs than for conventional metal-on-polyethylene THAs.Methods We retrospectively reviewed 537 THAs performed in 512 prospectively followed patients having THA between October 1996 and October 2000. Eleven patients (12 hips) were lost to followup before 2 years, leaving 501 patients (525 THAs); of these, 421 were alumina ceramic-on-ceramic articulations and 104 cobaltchromium-on-polyethylene. The mean age was 54 years. We determined acetabular cup inclination angles, Harris hip scores, Health-Status-Questionnaire-12 scores, and presence and location of any radiolucencies, osteolysis, or radiographic subsidence. We compared survival using the Kaplan-Meier method. The minimum followup was 24 months (mean, 59 months; range, 24-120 months). Results Twenty-two of the 424 THAs (4.2%) were revised. We observed no difference in clinical or radiographic outcomes with respect to cup inclination angles. Radiographically, two loose acetabular components and two femoral components had subsided. The 5-year survival rate was slightly higher for ceramic-on-ceramic bearings (98%) than for metal-on-polyethylene (92%).

Section: Methodsmentioning

confidence: 99%

Does Acetabular Inclination Angle Affect Survivorship of Alumina-ceramic Articulations?

Johansson

Johnson

Zywiel

et al. 2011

“…Future research might correlate radiographic signs with histologic and mechanical parameters to create a grading scale for osseointegration, which could have a similar clinical relevance to total joint arthroplasty grading systems [4,6,10,19]. Clinical applications of this approach might include assessment of whether implant design intentions are being met in animal translational studies and human preclinical trials.…”

Section: Discussionmentioning

confidence: 99%

Radiographic Evaluation of Bone Adaptation Adjacent to Percutaneous Osseointegrated Prostheses in a Sheep Model

Jeyapalina

Beck

Bachus

et al. 2014

Background Percutaneous osseointegrated prostheses (POPs) are being investigated as an alternative to conventional socket suspension and require a radiographic followup in translational studies to confirm that design objectives are being met. Questions/purposes In this 12-month animal study, we determined (1) radiographic signs of osseointegration and (2) radiographic signs of periprosthetic bone hypertrophy and resorption (adaptation) and (3) confirmed them with the histologic evidence of host bone osseointegration and adaptation around a novel, distally porous-coated titanium POP with a collar. Methods A POP device was designed to fit the right metacarpal bone of sheep. Amputation and implantation surgeries (n = 14) were performed, and plane-film radiographs were collected quarterly for 12 months. Radiographs were assessed for osseointegration (fixation) and bone adaptation (resorption and hypertrophy). The cortical wall and medullary canal widths were used to compute the cortical index and expressed as a percentage. Based on the cortical index changes and histologic evaluations, bone adaptation was quantified. Results Radiographic data showed signs of osseointegration including those with incomplete seating against the collar attachment. Cortical index data indicated distal cortical wall thinning if the collar was not seated distally. When implants were bound proximally, bone resorbed distally and the diaphyseal cortex hypertrophied. Conclusions Histopathologic evidence and cortical index measurements confirmed the radiographic indications of adaptation and osseointegration. Distal bone loading,

“…These were assessed independently by two reviewers (MDS, SAH) for the presence of progressive radiolucent lines at the acetabular bone-prosthesis interface in the zones described by DeLee and Charnley [11] and at the femoral bone-prosthesis interface in the zones described by Gruen et al [17]. Periprosthetic radiolucencies were considered clinically important if they were greater than 2 mm [26].…”

Section: Methodsmentioning

confidence: 99%

Custom Cementless THA in Patients with Skeletal Dysplasia Results in Lower Apparent Revision Rates than Other Types of Femoral Fixation

Sewell

Hanna

Muirhead-Allwood

et al. 2011

Background Patients with skeletal dysplasia are prone to degenerative hip disease thus requiring THA at a younger age than the general population. This is a technically demanding procedure with high complication and revision rates. Achieving good femoral fixation can be challenging because of the abnormal features of the hip. Questions/purposes We therefore determined: (1) survivorship, (2) function, (3) radiographic findings, and (4) complications associated with a cementless custommade femoral component used in THAs for patients with skeletal dysplasia and compared these parameters with those from other types of femoral fixation. Patients and Methods Between 1992 and 2005, 40 THAs were performed in 25 patients with skeletal dysplasia using custom-made cementless femoral components. There were 15 men and 10 women with a mean age of 37.5 years (range, 18-61 years) and a mean height of 145 cm (range, 120-173 cm). Patients were followed clinically and radiographically for a minimum of 4.3 years (mean, 10.1 years; range, 4.3-18.2 years). ResultsThe survivorship rates for the femoral and acetabular components were 92% and 70%, respectively, at 220 months. Revision arthroplasty was performed in four of 40 hips (10%). In two, the acetabular component was revised for aseptic loosening, one had both components revised for aseptic loosening, and one had an isolated femoral component revision for deep infection. The mean Harris hip score improved from 41 (range, 27-57) preoperatively to 80 (range, 51-94) at final followup. There were two intraoperative proximal femoral fractures and one dislocation. Conclusions When compared with studies with equal followup, custom-made cementless components in THAs for patients with skeletal dysplasia apparently had lower revision and complication rates with comparable function and higher midterm survival.