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At least 451 records · Page 25Linked to original sources
PubMed1996

The Rotaglide total knee arthroplasty. Prosthesis design and early results.

The Rotaglide knee (Cozim Medical, UK) is a three-part knee containing a mobile polyethylene meniscal platform, imparting reduced loosening forces to the tibia. The femoral component design provides a high degree of congruency throughout the range of motion from 0 degree to 110 degrees, and both femoral and tibial components ensure minimal bone removal. The system is versatile, including a large number of component options, and it may be used in both primary and revision arthroplasties. The first results in 170 cemented knees (161 patients) with 2- to 5-year follow-up periods (average, 3.1 years) were very encouraging (excellent or good in 95% of knees, based on the British Orthopaedic Association knee assessment system). Poor results were seen only in revision cases. There have been no mechanical implant failures and no platform bearing dislocations, and the platforms continue to move as documented by postoperative roentgenograms, which show the metal markers of the platforms moving anteriorly in flexion and posteriorly in extension.

Aged↗
PubMed1993

Parametric modelling of a knee joint prosthesis.

This paper presents an approach for the establishment of a parametric model of knee joint prosthesis. Four different sizes of a commercial prosthesis are used as an example in the study. A reverse engineering technique was employed to reconstruct the prosthesis on CATIA, a CAD (computer aided design) system. Parametric models were established as a result of the analysis. Using the parametric model established and the knee data obtained from a clinical study on 21 pairs of cadaveric Asian knees, the development of a prototype prosthesis that suits a patient with a very small knee joint is presented. However, it was found that modification to certain parameters may be inevitable due to the uniqueness of the Asian knee. An avenue for rapid modelling and eventually economical production of a customized knee joint prosthesis for patients is proposed and discussed.

Asian People↗
PubMed1997

Psoriasis is a risk factor for hip-prosthesis infection.

Risk factors for hip and knee prosthesis infection have been described, but not psoriasis. Eighty five infected patients from different centers and 202 non infected patients were included in a case-control study. Fifteen of 85 infected patients (17.6%), and 2 of 202 (1%) non infected patients had psoriasis. Odds ratio for infection in patients with psoriasis is 21.4 (4.7-195.5), and 39.7 (5.3-1718.8) in patients with hip prosthesis and psoriasis. No significant difference was found in patients with knee prosthesis. These data indicate that psoriasis is a risk factor for hip prostheses infection.

Case-Control Studies↗
PubMed1980

Review of a failed knee replacement and some observations on the design of a knee resurfacing prosthesis.

In a review of failed knee replacements, one design was found to have a seventy-three percent failure rate at three years. In this design the tibial component resembled the MacIntosh prosthesis and the femoral component was polyester. Failure in most cases resulted from generation of wear debris resulting in a severe synovitis and loosening of the femoral component. These findings suggest that the femoral component should be metal and the tibial component plastic, and that if the tibial component is backed with metal, in most cases it need not be cemented in place.

Humans↗
PubMed1990

The APS knee joint prosthesis. A review of 32 patients.

First clinical and radiographic results with a new knee joint prosthesis, implanted without cement, are reported and the characteristics of the implant (dowel fixation and special instrumentation) presented. The first series of 35 joints with a follow-up period of 1-3 years shows excellent results. Radiographically, primary osseous integration cannot be positively identified in all cases, but it could be proved in most instances. Cement-free implantation requires good preoperative bone quality and an operative technique which inserts the implant anatomically. If these two conditions are met, there is every probability of successful implantation. No problems specific to the implant have been encountered.

Adult↗
PubMed1984

Torsion and bending imposed on a new anterior cruciate ligament prosthesis during knee flexion: an evaluation method.

A new composite prosthesis was recently proposed for the anterior cruciate ligament. It is implanted in the femur and the tibia through two anchoring channels. Its intra-articular portion, composed of a fiber mesh sheath wrapped around a silicone rubber cylindrical core, reproduces satisfactorily the ligament response in tension. However, the prosthesis does not only undergo elongation. In addition, it is submitted to torsion in its intra-articular portion and bending at its ends. This paper presents a new method to evaluate these two types of deformations throughout a knee flexion by means of a geometric model of the implanted prosthesis. Input data originate from two sources: (i) a three-dimensional anatomic topology of the knee joint in full extension, providing the localization of the prosthesis anchoring channels, and ii) a kinematic model of the knee describing the motion of these anchoring channels during a physiological flexion of the knee joint. The evaluation method is independent of the way input data are obtained. This method, applied to a right cadaveric knee, shows that the orientation of the anchoring channels has a large effect on the extent of torsion and bending applied to the implanted prosthesis throughout a knee flexion, especially on the femoral side. The study suggests also the best choice for the anchoring channel axes orientation.

Biomechanical Phenomena↗
PubMed1982

[The Anatomical sliding-axis knee-joint prosthesis (author's transl)].

In order to avoid the disadvantages of a fixed axis the newly-designed knee-joint prosthesis was equipped with a sliding one. This is not a load-bearing component; its main purpose is to guide the movement of the endoprosthesis. The design permits almost physiological movement, thus diminishing the detrimental forces at the anchor points. To further improve anchoring the shafts of the prosthesis were designed with an anatomical cross-section. The design of the anatomical sliding-axis prosthesis is described and the results of the first 36 implantations are presented.

Biomechanical Phenomena↗
PubMed1996

Total replacement of the metatarsophalangeal joint in the horse. A single pilot study.

In this paper the successful replacement of an equine metatarsophalangeal joint by a human total condylar knee prosthesis is reported. In the period of observation following implantation of the endoprosthesis the experimental animal showed almost no lameness when exercised at walk, bearing weight on the operated limb. Flexion and extension of the joint were markedly reduced. The clinical and histological observations clearly support further investigation into the equine metatarsophalangeal joint replacement by an endoprosthesis.

Animals↗
PubMed1976

Hyperextension complicating total knee replacement.

An elderly man with bilateral total knee replacements had an unusual hyperextension probelm complicating one knee prosthesis. A new type of orthosis which was fitted to the patient corrected the hyperextension. The management of the patient is described. The goal of treatment was to help this man become ambulatory and independent in activities of daily living. He progressed sufficiently to return to his own apartment in the city where he lives alone.

Aged↗
PubMed1992

The exposed total knee replacement prosthesis: a new classification and treatment algorithm.

The increased frequency of total knee replacement arthroplasty (TKRA) has been reflected in the number of patients with exposed prostheses referred to this unit. An algorithm has been developed to assist in the preoperative assessment of the wound and this has been tested on 25 patients with wound breakdown following TKRA. The grade of exposure so derived predicts the most appropriate surgical management. The algorithm, grading system and proposed management are described.

Algorithms↗
PubMed1998

Can a total knee replacement prosthesis be made entirely of polymers?

We have prospectively studied 63 total knee replacements (TKR) in which the femoral component was polyacetal, and 138 TKRs in which the femoral component was conventional cobalt chrome. The tibial and patellar components were of ultrahigh molecular weight polyethylene (UHMWPE). Patients were followed-up for at least 10 years. In the polyacetal group, a number of patients have died or have been revised, for reasons unrelated to the presence of polyacetal. There were no instances of femoral component fracture, nor failure by wear. One postmortem specimen, retrieved at 9 years after surgery, showed no measurable polyacetal wear and negligible HDP wear. The histology of tissue in contact with polyacetal was indistinguishable from that adjacent to polymethyl methacrylate and UHMWPE in the same knee. We believe that polyacetal could be used for the femoral component of a TKR and that a further trial should be undertaken.

Acetals↗
PubMed2001

Comparison of fixed-bearing and mobile-bearing total knee arthroplasties.

The purpose of the current study was to directly compare the results of fixed-bearing and mobile-bearing total knee arthroplasties in the same patient who had bilateral simultaneous total knee replacements. A fixed-bearing total knee prosthesis (AMK) was implanted in one knee and a mobile-bearing total knee prosthesis (LCS) was implanted in the other knee in 116 patients. The average age of the patients was 65 years (range, 33-70 years). The average followup was 7.4 years (range, 6-8 years). Clinical and radiographic followup was done using Knee Society and Hospital for Special Surgery knee rating systems at 6 weeks, 3 months, 6 months, 1 year after surgery, and yearly thereafter. Total knee score, pain score, mean functional score, and range of motion were comparable in both groups. Two knee replacements (2%) in one patient with AMK prostheses were revised because of complete wear of tibial bearing polyethylene. One knee replacement (1%) in one patient with an LCS prosthesis was revised because of dislocation of the medial tibial bearing polyethylene and one knee replacement (1%) in one patient with an LCS prosthesis was revised because of complete wear of the medial tibial bearing polyethylene. No knee had aseptic loosening or osteolysis in either group. After a minimum followup of 6 years, the results of fixed- and mobile-bearing total knee prostheses in the current series are favorable. However, there is no evidence to prove the superiority of the mobile-bearing total knee design.

Adult↗