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 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of the European total hip arthroplasty in the sixties of 20th century is associated mainly with the names of G. K. McKee, J. Charnley and M. E. Muller. The SICOT meeting in Paris in 1966 introduced THA as a new method of treatment of osteoarthritis of the hip and paved the way for the commercialization of the manufacturing of prostheses. The success of this method consisted primarily in the fixation of individual components by bone cement and application of metal-to-polyethylene and metal-to-metal joints. The book presents these historical events as they have been reflected in the development of THA in the countries of the former Czechoslovakia and in the development of implants of domestic provenance. The development of THA in the former Czechoslovakia started in 1969 and was based on the Swiss school established by M. E. Muller. The Muller component with the "banana-shaped" stem was implanted using the Watson-Jones approach, the proximal femur canal was prepared by a rasp and the Palacos cement was used. This prosthesis served also as the model for the first Czech implant Poldi-Cech of I generation (the Chirulen cup available in three sizes, the "banana- shaped" femoral component with a 32 mm head-diameter and 130 degree neck-shaft angle) the development of which started in 1969 and the serial production began in 1972 in the Poldi Kladno steel company. Fatigue fractures of the "banana-shaped" stem led to the development of the concept of a femoral component with an "anatomical" stem. In Switzerland, this concept was developed by B. G. Weber. In the former Czechoslovakia the development of a new femoral component with an "anatomical" stem following the shape of the intramedullary canal with an ovoid profile and without sharp edges started in 1972. Due to the incidence of fatigue fractures of the "banana-shaped"stem and material that was not sufficiently strong (steel used for the production of osteosynthetic components), 144 degree neck-shaft angle was chosen. Reduction of the effect of bending forces on the valgus stem had eliminated fatigue fractures. This Poldi-Cech prosthesis of II generation was provided in nine sizes. The diameter of the head remained the same. Three Chirulen cups were supplemented with a "flat" cup for implantation in a dysplastic acetabulum. The prosthesis was implanted with an exact instrument set (reamer for acetabular preparation, rasp for proximal femoral preparation, alignment device for accurate positioning of both the cup and the femoral component) with the use of the Palacos cement. The production of the Poldi-Cech prosthesis of II. generation started in 1974 with the fabrication of a monoblock. Since 1986 it has been developed into a modular system (14/16 cone) with the possibility to use a ceramic head of 32 mm diameter (only in the nineties the cone size was changed to 12/14 and the heads were provided also in the 28 mm diameter). The Poldi-Cech prosthesis of II generation with the "anatomical" stem has been implanted since 1974 (i. e. during 30 years) in more than 140 000 patients in the Czech and Slovak Republics. In the same year cemented monoblock hemiarthroplasty was developed on the same basis as THA using the same "anatomical" stem and 36 to 60mm head diameter. Until now more than 35,000 of these hemiarthroplasty systems have been implanted. Until 1992 the Poldi-Cech implant was practically the only available cemented total hip replacement in the former Czechoslovakia and retrospectively it may be considered a highly successful implant. In the authors' view, the further development of THA will lead in the following years to the use of implants proved by a long-term follow-up. Preference will be given to prostheses the implantation of which will require a minimal loss of the bone stock during primary surgery and which will allow a technically easy reimplantation. The continental Europe has been recently preferring hybrid prostheses while Scandinavia witnesses an evident increase in the number of implanted cemented prostheses to the detriment of the cementless and hybrid ones. Naturally, cementless prostheses will keep dominating in young patients.
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PMID:The European school of total hip arthroplasty and 35 years of total hip arthroplasty in the Czech Republic. 1586 Jan 55

The use of cementless threaded cups in THA is a well-established treatment. Fractures of the cups are rare complications recorded in individual cases with material defects being discussed as the primary cause. We analyzed three cases of fractured cups. Although all three cups were well fixed to existing bone, we observed deficient osseous backing dorsocranially and abrasion particles. There were no signs of femoroacetabular impingement or infection. The cups showed corrosion debris. Scanning electron microscopic investigations showed characteristics of fretting and fretting-related corrosion. We concluded the fractures occurred because of fretting combined with inadequate bony support leading to fatigue of the material and subsequent fracture.
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PMID:Case reports: fractures of threaded cups: rare complications of a well-established implant. 1882 Sep 84

Bone loss around femoral implants used for THA is a persistent clinical concern. It may be caused by stress shielding, generally attributed to a mismatch in stiffness between the implants and host bone. In this regard, a fatigue resistant, carbon fiber (CF) composite femoral implant with bone-matching stiffness has been developed. This study evaluated the tissue response to the three material components of this implant in normal and textured (blasted with 24 grit alumina) surfaces: the hydroxyapatite (HA) coating, the CF composite and the intermediate crystalline HA particulate composite layer to bond to the HA coating (blended). Sprague-Dawley rats underwent bilateral femoral implantation each receiving two rod-like implants. Bone apposition to the HA (37%) and textured Ti (41%) implants was not significantly different. Bone apposition to the untextured CF (14%) and blended (19%) implants and polished Ti (8%) implants was significantly lower. Bone apposition to the textured CF (9%) and blended (11%) implants was lower (but not statistically from the as received or untextured counterparts). Nearly all sections from femurs containing CF implants presented CF debris. There was no evidence of localized bone loss or any strong immune response associated with any of the implant materials. All materials were well tolerated with minimal inflammation despite the presence of particulate debris. The high degree of bone apposition to the HA-coated composite implants and the lack of short-term inflammation and adverse tissue response to the three material implant component support continued evaluation of this composite technology for use in THA.
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PMID:Tissue response to the components of a hydroxyapatite-coated composite femoral implant. 2073 Sep 32

In order to verify whether orthostatic posturography (OP) can support clinical assessment of total hip (THA) and knee arthroplasty (TKA), 81 subjects with THA and 100 with TKA were recruited and compared with 59 healthy volunteers. All patients were tested one or two days prior to surgery; 42 subjects (20 THA and 22 TKA) were tested again after six months, and 34 (14 THA and 20 TKA) yet again after 12 months. OP was performed using a Kistler 9286A piezoelectric force plate and the following postural parameters (PPs) were adopted on account of their functional meaning: mean velocity and the root mean square of the distance of the centre of pressure (CoP), sway area, and 95% of the CoP power frequency. Eye condition and fatigue related to the test duration were also examined. The three most meaningful PPs were identified and a logarithmic transformation was then applied to these, as well as standardization. Almost all the PP values were higher preoperatively in the patients as compared with the healthy subjects and it was possible to detect many statistically significant differences between patients and healthy subjects. However, when examining the 181 subjects at the preoperative stage, the PPs did not show congruence with the clinical scores as well as they did during follow-up. Therefore, the use of the OP is not recommended to monitor patients undergoing THA or TKA.
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PMID:Relevance of orthostatic posturography for clinical evaluation of hip and knee joint arthroplasty patients. 2148 15