Authors: Rocco Paolo Pitto, N. Schikora, Gerd Willmann, B. Graef, R. Schmidt
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Authors: Clifford W. Colwell, J.A. D'Antonio, W.N. Capello, M.E. Hardwick
Abstract: Alumina ceramic is an excellent material for biologic implantation. Decreased particulate wear debris should increase implant longevity. The purpose of this study is to examine clinical and radiological results of ceramic-on-ceramic hip implants compared to cobalt chrome on polyethylene.
Four cementless systems were compared, three alumina-on-alumina bearing systems: System I, porous coated cup; System II, hydroxyapatite-coated cup; Trident system, hydroxyapatite-coated cup with metal sleeve backing on ceramic cup liner; and System III (control), porous-coated cup with polyethylene and cobalt chromium bearing system. Patients were randomized to receive System I,
II, or III. Trident patients were not randomized. Examinations are performed at 6 months, 1 year and yearly thereafter including x-rays, clinical exam and Harris Hip Score (HHS). Minimum 24-month followup was performed in 562 ceramic hips and 154 control hips. Age, height, weight, gender and diagnosis were similar in all groups. HHS was rated good/excellent by 95 percent of ceramic hips and 97 percent of control hips. Radiographic results demonstrated radiolucency in Femoral Gruen Zone 1 in 3.8 percent (18/474) of ceramic hips and in 8 percent
(10/128) of control hips. Unstable acetabular components were reported in none of ceramic hips and in 3.2 percent (5/154) of control hips. Revision was performed in 7 (1.2 percent) ceramic hips, none due to failure of ceramic materials, and in 9 (5.8 percent) control hips. Alumina ceramic materials
show promise, but continued evaluation of long-term clinical results is needed.
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Authors: Gregory Y. Lee, Ajay Srivastava, Darryl D. D'Lima, Pam Pulido, Clifford W. Colwell
Abstract: The Omnifit-HA femoral stem component has shown excellent results in early clinical
studies. This is an independent prospective study of the outcome of a ydroxyapatite-coated femoral component implanted by one surgeon with an intermediate-term follow up. The senior author performed 103 consecutive uncemented total hip arthroplasties in 96 patients from July 1991 to December 1996. The components implanted were the Omnifit-HA femoral stem and the Omnifit PSL porous-coated acetabular shell. The mean age at the time of the index procedure was 52 years old
(range, 27–78) and male:female ratio was 54:42. Three patients were deceased and four patients were lost to follow-up. The mean follow up was 10.3 years (range, 7.3–12.7 years). Clinical and radiographic evaluations were performed by an independent observer. The average preoperative and postoperative Harris Hip Scores were 55 and 92, respectively. The overall survivorship of the
Omnifit-HA stem was 100% with no femoral revisions. The survivorship of the Omnifit PSL cup was 89.7% with 4 acetabular revisions for aseptic loosening and 6 polyethelene liner exchanges for osteolysis or late instability. The mean polyethylene wear rate was 0.24 mm per year. This long-term follow up shows that the use of circumferentially coated hydroxyapatite stems can protect against the
migration of wear debris along the femoral stem.
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Authors: Jeong Joon Yoo, Hee Joong Kim, Young Min Kim, Kang Sup Yoon, Kyung Hoi Koo, Kwang Woo Nam, Sang Ik Shin
Abstract: Limitation in liner and head options available to the surgeon may be the most practical
disadvantage of alumina-on-alumina total hip arthroplasty (THA). This may be more problematic in the revision THA. We evaluated the results of 57 revision THAs (average, 46.2 years old) performed with a contemporary alumina-on-alumina bearing surface after a 5-year minimum follow-up (average, 67 months; range, 60-85 months). A third generation alumina-on-alumina bearing (BIOLOX® forte, CeramTec AG) and a cementless PLASMACUP®-BiCONTACT® hip
revision system (AESCULAP AG & Co.) had been used in all patients. Alumina bearing was chosen for a relatively young active patient in whom an acetabular bone defect was not severe and an extremely long neck of artificial head was not required for the restoration of hip joint mechanics. The average Harris hip score improved from 65.0 points to 88.9 points. No implant loosened, no stem or cup was re-revised, and no additional reoperations were required. Ceramic wear was
undetectable in 14 hips where differentiation of the femoral head from the cup was possible on radiographs and no osteolysis was observed. During the follow-up period, no hip demonstrated signs of infection or ceramic failure. Short-term results of revision THAs performed with analumina-on-alumina bearing are encouraging. We believe that physiological age and activity level of a patient, severity of acetabular bone loss, and availability of alumina head and liner options
required for the restoration of proper limb length and joint stability should be considered to choose this alumina bearing surface during the revision THA.
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Authors: Jeong Joon Yoo, Hee Joong Kim, Young Min Kim, Kang Sup Yoon, Kyung Hoi Koo, Kwang Woo Nam, Yong Lae Kim
Abstract: Medial placement of a cementless acetabular component into or beyond the medial wall of
a shallow, dysplastic acetabulum is a technique to enhance its coverage during difficult total hip
arthroplasty (THA). Dysplastic hips almost always need small size of acetabular component, so an
accelerated polyethylene wear can occur when a conventional bearing surface is used. Modern
alumina-on-alumina couplings can be an alternative for these patients. We evaluated the clinical
results of 43 medially placed cementless acetabular components (PLASMACUP®SC) incorporating a
modern alumina bearing surface (BIOLOX® forte). Acetabular components were inserted medially
beyond the ilioischial line and, therefore, beyond the level of the cortical bone of the cotyloid notch,
and followed up for more than 5 years (range, 60 – 93 months). In 14 hips, the medial acetabular wall
was perforated purposefully and the medial aspect of the cup was placed beyond both the ilioischial
and the iliopubic line on radiographs. The mean Harris hip score improved from 55.3 points
preoperatively to 94.5 points postoperatively. Postoperatively, the hip center migrated 12.1 mm
medially and 1.5 mm inferiorly. The average amount of cup protrusion beyond the ilioischial and the
iliopubic line was 3.1 mm and 1.9 mm, respectively. The average superolateral coverage of the cup
was 98.5 percent. During follow-up, no osteolysis or loosening of acetabular components was
observed and no revision was required. Medial placement of a cementless acetabular component into
or beyond the medial acetabular wall offers predictable clinical results and durable fixation in modern
alumina-on-alumina THA.
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