Aims. Radiostereometric analysis (RSA) is the most accurate radiological method to measure in vivo wear of highly cross-linked polyethylene (XLPE) acetabular components. We have previously reported very low wear rates for a sequentially irradiated and annealed X3 XLPE liner (Stryker Orthopaedics, USA) when used in conjunction with a 32 mm femoral heads at ten-year follow-up. Only two studies have reported the long-term wear rate of X3 liners used in conjunction with larger heads using plain radiographs which have poor sensitivity. The aim of this study was to measure the ten-year wear of thin X3 XLPE liners against larger 36 or 40 mm
Purpose. The results of ceramic-on-ceramic (CoC) bearing surfaces in primary total hip arthroplasty (THA) were well known. However, it was not known in revision THA. The purpose of this study is to report the results of revision THA with ceramic
Late aseptic loosening of total hip arthroplasty (THA) components due to wear debris especially sub-micron Polyethylene induced osteolysis has been identified to be the major cause for revision. Therefore, the use of wear resistant designs and materials is imperative for the long-term success of articulating implants. One of the most promising
Early revision is an important risk factor for repeated revision and poor results after primary total hip replacement and instability is a major cause of early revision. Larger
Background: Metal on metal
The anatomy of the first metatarsophalangeal (MTP) joint and, in particular, the metatarsosesamoid
Introduction. The Metasul
Introduction: Total hip replacements (THR) with the first generation metal-on-metal
Introduction. Mobility at insert-tray
Background. The anatomy of the human knee is very different than the tibiofemoral surface geometry of most modern total knee replacements (TKRs). Many TKRs are designed with simplified articulating surfaces that are mediolaterally symmetrical, resulting in non-natural patterns of motion of the knee joint [1]. Recent orthopaedic trends portray a shift away from basic tibiofemoral geometry towards designs which better replicate natural knee kinematics by adding constraint to the medial condyle and decreasing constraint on the lateral condyle [2]. A recent design concept has paired this theory with the concept of guided kinematic motion throughout the flexion range [3]. The purpose of this study was to validate the kinematic pattern of motion of the surface-guided knee concept through in vitro, mechanical testing. Methods. Prototypes of the surface-guided knee implant were manufactured using cobalt chromium alloy (femoral component) and ultra-high molecular weight polyethylene (tibial component). The prototypes were installed in a force-controlled knee wear simulator (AMTI, Watertown, MA) to assess kinematic behavior of the tibiofemoral
A ceramic is currently considered as the most ideal
Osteolysis caused by polyethylene wear particles leads to loosening or bone destruction. Attempts to minimise wear rely largely on selection of the most suitable materials for the purpose. This is typically stainless steel, cobalt chromium or ceramic for the femoral head and primarily polyethylene on the acetabular side. However, there is increased use of both ceramic-on-ceramic and metal-on-metal
Aims: A polyethylene free, metal on metal acetabular system (Hofer-Imhof cup; Lubrimet metal on metal
Aims: A polyethylene free, metal on metal acetabular system (Hofer-Imhof cup; Lubrimet¨ metal on metal
Introduction. There is interest in minimally invasive solutions that reduce osteoarthritic symptoms and restore joint mobility in the early stages of cartilage degeneration or damage. The aim of the present study was to evaluate the Biolox®delta alumina-zirconia composite as a counterface for
Introduction: Ceramic/ceramic
Introduction: There has been a renewed interest in metal-on-metal
Purpose. This study was undertaken to assess the result of total hip arthroplasty (THA) performed for fused hips. Patients and Methods. Twenty nine patients (31 hips), aged 21 to 70 years (average 46 years), underwent THA conversion surgery and were followed for an average of 4.6 years (2.4-12.0 years). There were 23 cases of spontaneous fusion and 8 case of surgical fusion. The causes of joint fusion were tuberculosis in 6 hips, childhood coxitis in 13, ankylosing spondylitis in 6 and childhood trauma in 4. Modified two incision technique was used in 9 hips and in 22 hips, the surgery was performed through a posterolateral approach combined with anterior capsulotomy through gluteus medius and tensor fasica lata interval. In 1 case, greater trochanter osteotomy was done. All acetabular components were inserted at the true acetabulum and the
Purpose: A single blind prospective randomised controlled trial comparing the Metal-on-polyethylene
Aspetic loosening is a major problem of total hip arthroplasty, especially in young and/or active patients. This study was performed to assess the clinical performance of non-cemented, metal-on-metal implant and complications including loosening and osteolysis at medium-term follow-up. Between 1994 and 1998, 38 patients (45 hips) had a THA with a Metasul