Charnley Type Research Articles

Investigation for the Effects of Newly Designed Hip Prosthesis on Crack Propagation Using Probabilistic Methodology

In orthopedic prosthesis design, finite element method is one of the commonly used mathematical methods for performing structural analyzes and reducing test costs before it is applied to the patient. Surgeons and engineers should work together to design reliable durable and hip replacement. Desirable functional requirements for prosthesis design include high fatigue life, small relative displacement between the prosthesis-cement interface, and reduced stress on the bone and prosthesis. For this purpose, the progression of the fracture was calculated by applying the scenario of the presence of crack in the bone cement of the designed prosthesis using optimization methodology. The same conditions were analyzed in commercially available Charnley type prosthesis and the results were compared. When the obtained results are examined, it is seen that the newly designed prosthesis is more effective than the Charnley type prosthesis.

Assessment of efficacy of charnley type and modular type total hip prosthesis in patients undergoing total hip arthroplasty: A comparative study

Background: Arthroplasty is an operation to restore pain free motion to a joint and function to the muscles, ligaments and other soft tissue structures that control the joint. Evaluation of the long-term outcomes of an operative procedure is important to determine the durability of the results of the procedure. In addition, it provides a mean for comparison with the results of any changes in the procedure, including alterations in operative technique, implant design, type of joint - cemented and non-cemented hybrid that occur over times. Hence; we evaluated the results of total hip arthroplasty specially comparing most commonly performed modular type with charnley type i.e. fixed type of THR. In our institute modularity in respect to neck length is used.Materials & methods: 30 patients of either sex, who were operated for total hip replacement, were assessed. Each case was subjected to detailed history regarding age at operation, sex, indication of surgery, type of replacement, duration after replacement, any associated comorbid condition that may affect outcomes of total hip replacement, whether joint replacement was unilateral / bilateral. A scoring system used by Harris called as Harris hip scoring system was used to evaluate the patients. 100 points will be given to a person who can painlessly walk without any support or limp and the walkable distance should not be limited. All the results were analyzed by SPSS software. Results: 2(13.33%) patient in Charnley Group developed dislocation which was managed by closed reduction and traction for 6 weeks. 1(6.67%) Patient in Charnley Group developed peri prosthetic fracture which was managed by open reduction and internal fixation with plating and circlage wire. No patient in the group both groups had shortening more than 2 cms. There was no lengthening in any of the patients. The average Harris Hip Score in Modular Group patients was 85.67 and in Charnley Group was 79.87. Conclusion: Since appreciable limb length shortening and dislocation of hip after fixed type is seen in this study so our results shows that Modular type of hip prosthesis is better than fixed type prosthesis (Charnley type hip prosthesis).

The relationship between constitutional alignment and varus osteoarthritis of the knee.

The role of neutral alignment in total knee arthroplasty (TKA) on short- and long-term outcomes has become controversial. Based on the concept of constitutional varus, it has been suggested that under-correction in TKA in a varus osteoarthritis (OA) population might lead to better clinical outcomes. However, it is still unknown what the relationship between constitutional varus and the development of end-stage OA is. The goal of this study was to analyse the contribution of constitutional varus in a medial OA population and to define a correlation between the constitutional alignment and end-stage varus OA. Based on full-length radiographs, corrected for the intra-articular deformity of the knee, of 315 patients with unilateral end-stage medial OA of the knee (Charnley type A), a correlation in the coronal plane was made between medial end-stage OA and the contralateral non-arthritic side. With increasing varus alignment in the arthritic limb, the physiologic limb alignment also became more varus. The proportion of constitutional varus rose with increasing overall alignment and was found to be continuous for males. Constitutional varus was three times higher in men when the overall arthritic alignment was greater more than 6° varus. Constitutional varus significantly contributes to varus osteoarthritis and was found to be higher than in the general population. III.

Analysis of the Non-union of the Greater Trochanter after Total Hip Replacement (Charnley Type)

Analysis of the Non-union of the Greater Trochanter after Total Hip Replacement (Charnley Type)

Follow-up Study of Charnley Type Total Hip Replacement

Follow-up Study of Charnley Type Total Hip Replacement

高齢者 (75歳以上) に対する Charnley 型全人工股関節置換術の治療成績

高齢者 (75歳以上) に対する Charnley 型全人工股関節置換術の治療成績

Faut-il systématiquement changer une pièce fémorale monobloc cimentée lors d’une reprise d’arthroplastie totale ? Évaluation prospective

The main reason for revision of Charnley type total hip arthroplasty is socket loosening related to high polyethylene wear and periacetabular osteolysis. In these situations, the monobloc cemented stem is frequently not loosened and it is not clear whether the femoral component can be retained during the revision procedure. The aim of this study was to evaluate surface and sphericity damage to the femoral head of a prospective and consecutive series of revision total hip arthroplasties during which the cemented monobloc femoral component has been systematically revised. We performed 22 revisions of both components of Charnley type cemented total hip arthroplasties. In all cases, the 22.2 mm head of the monobloc femoral component was made of 316 L stainless steel. The international standard for such femoral heads includes an average surface roughness (Ra) of 0.05 microm, a total roughness (Rt) value of 0.5 microm and a sphericity of +/-5 microm. The mean age of the patients at the time of the index arthroplasty was 51.3 years. The average time to revision was 14.8 years (seven to 25 years). The reasons for revision included isolated socket loosening (12), extensive periacetabular osteolysis without socket loosening (two), recurrent dislocation associated with socket loosening (one), sepsis without implant loosening (one), loosening of both components (one), and isolated loosening of the femoral component (five). Hence, 15 of the 22 (68.2%) femoral components could theoretically have been retained. The surface roughness of the femoral heads was evaluated using a contact-type profilometer. For each head, the apex and two zones, either macroscopically scratched or with loss of the mirror finish, were analyzed. Moreover, the sphericity of the heads was measured using a spherometer. The stem explanted after recurrent dislocation was analyzed separately as the femoral head had major scratches. The mean Ra and Rt of the series at the apex was 0.029 and 0.876 microm, respectively. The mean Ra and Rt of the series for the macroscopically damaged areas was 0.05 microm and 1.540 microm, respectively. The mean sphericity of the series was 7.2 microm. Hence among the 22 explanted stems, 10 femoral heads (45.4%) had Ra or Rt apex and 18 (81.8%) Ra or Rt scratched area values beyond ISO standards, respectively. Sphericity was greater than +/-5mm for 13 of the 22 femoral heads (59.1%). With the numbers available, the age at the time of the index arthroplasty, the BMI, the time and the reason for revision were not significantly associated with the degree of femoral head damage for both roughness and sphericity parameters. Retaining the femoral component during revision of the total hip arthroplasty including a monobloc femoral component is theoretically an interesting alternative. However, femoral head surface damage occurring in vivo would have lead us to retain severely scratched heads in over 80% of the hips, and heads with abnormal roughness and sphericity values in over 90% of the hips. Bases upon our results, we recommend systematically revising the femoral component during revision THA including a monobloc stem, irrespective of the reason for revision.

Survie à 16,5 ans de recul moyen de la cupule, double mobilité, non scellée de Bousquet dans l’arthroplastie totale de hanche. Série historique de 437 hanches

The purpose of this study was to evaluate the long-term results of a retrospective series of primary arthroplasty with a cementless dual mobility socket and a cemented Charnley type femoral component. This study included 437 hip replacements performed between 1984 and 1990, in 388 patients. The Bousquet's acetabular component, an original concept of cementless dual mobility socket has been used, associated with a cemented Charnley type femoral component. A clinical and radiologic analysis was done. The outcome is known for 345 hips (79%): 164 alive without revision at a mean of 16,5 years follow-up, 137 died without revision and 44 failures. Ninety-two (21%) were lost at follow-up. According to Kaplan-Meier analysis, the 5-year survival rate, was 84,4%+/-4,5 with revision for any reason (infection, dislocation, osteolysis...) for end point. Revision, for aseptic loosening of femoral or acetabular component, was performed in 30 hips (6,8%). Five dislocations occurred and were revised: two early related to technical errors and three after 10 years or more of follow-up. The young age of the patients at the time of the index surgery was correlated with higher rate of aseptic loosening. The prevalence of revision for dislocation is very low in our series. This concept does not avoid wear, osteolysis and aseptic loosening, especially in young active patients but the long-term stability is confirmed. We recommend this type of prosthesis for patients over 70 years and for younger patients with high risk of dislocation Q.

Simulated crack propagation in cemented total hip replacements

The purpose of this investigation was to determine the specific fracture mechanics response of cracks that initiate at the stem–cement interface and propagate into the cement mantle. Two-dimensional finite element models of idealized stem–cement–bone cross-sections from the proximal femur were developed for this study. Two general stem types were considered: rectangular shape and Charnley type stem designs. The FE results showed that the highest principal stress in the cement mantle for each case occurred in the upper left and lower right regions adjacent to the stem–cement interface. There was also a general decrease in maximum tensile stress with increasing cement mantle thickness for both rectangular and Charnley-type stem designs. The cement thickness is found to be one of the important fatigue failure parameters which affect the longevity of cemented femoral components, in which the thinner cement was significantly associated with early mechanical failure for short-time period.

Common Features on Damage Mechanisms Identified on Various Metal and Ceramic on Polyethylene Articulating Surfaces of Total Hip Prostheses

This paper presents a methodology for assessing the in-vivo degradation mechanisms of articular components of total hip replacement (THR) prostheses of Charnley type. The experimental procedure revealed that common features can be observed even if the clinical cases under investigation were quite different with regard to the demographic data. It particularly emphasises the detrimental effects of foreign bodies on the damage of the articulating surfaces. These foreign bodies can migrate into the joint space before embedding definitely into the Ultra High Molecular Weight Polyethylene (UHMWPE) acetabular cup surface where they further participate to a third body wear mechanism accelerated by a progressive increase of the femoral head roughness. Our experimental results underline, from a practical point of view, the need for careful manufacturing and clinical handling of porous surfaces, advocate for a systematic assessment of retrieved components, particularly when changed because of unexplained wear, and make questionable the clinical use of multifilament trochanteric cables.

A case report of dislocations after Charnley type total hip replacement

A case report of dislocations after Charnley type total hip replacement

Biomechanical finite element analysis of bone cemented hip crack initiation according to stem design

The purpose of this investigation was to determine the specific fracture mechanics response of cracks that initiate at the stem-cement interface and propagate into the cement mantle. Two-dimensional finite element models of idealized stem-cement-bone cross-sections from the proximal femur were developed for this study. Two general stem types were considered; Rectangular shape and Charnley type stem designs. The FE results showed that the highest principal stress in the cement mantle for each case occurred in the upper left and lower right regions adjacent to the stem-cement interface. There was also a general decrease in maximum tensile stress with increasing cement mantle thickness for both Rectangular and Charnley-type stem designs. The cement thickness is found to be one of the important fatigue failure parameters which affect the longevity of cemented femoral components, in which the thinner cement was significantly associated with early mechanical failure for shot-time period.

Identification of scratch mechanisms on a retrieved metallic femoral head

The degradation of the femoral head roughness caused by scratching is known to increase the wear rate of the polyethylene counterface of the Charnley total hip prostheses and therefore to have an impact on osteolysis. The knowledge of the scratching mechanism is hence of paramount importance to improve the long-term clinical performance of these prostheses. The aim of this study is to identify the mechanism of scratch generation of a retrieved titanium (TA6V) femoral head through an accurate characterisation of its surface topography. The surface topography features have been assessed both qualitatively and quantitatively by respectively using an optical microscope and a three dimensional contacting profilometer. Based on the scanning of about 80 areas spread over the entire surface of the retrieved femoral head, hypotheses on the mechanism of scratch generation have been formulated after analysing the observed topographical patterns, the arithmetic mean roughness and the amplitude density function (ADF). The formulated hypotheses have finally been verified comparing the ADF and the bearing area curves of profiles related to the most severely scratched areas with those of simulated worn profiles. This study highlights the major influence of foreign third bodies on the scratching of metallic femoral heads of the Charnley type prostheses.

Faulty design increases the risk of neck fracture in a hip prosthesis.

From October 1993 to May 1994, we performed 35 total hip arthroplasties (20 women) using a Charnley type modular 28 head manufactured by Medical Tee Brazil. 9 fractures through the neck of the stem prostheses occurred, all but 1 in men, after mean 4 (0.3-6) years. All fractures were due to an inadequate confluent radius causing abnormal transmission forces through the neck. The higher the load (men, heavy body weight), the greater the risk of fracture. The metallographic, chemical and microhardness analyses showed no abnormalities. We ascribe these fractures to faulty design of the stem prosthesis.

Infected Total Hip Replacement of Charnley type (11 Hips)

Infected Total Hip Replacement of Charnley type (11 Hips)

A Study of the Total Hip Replacement

Since 1971, eighteen total hip replacements in seventeen patients have been performed in our clinic. The age ranged from thirty eight to seventy seven years. Eleven joints in ten patients were replaced by McKee type, six Charnley type, and one Weber-Huggler type. The operation was most effective for the relief of pain. The improvement of gait was good. There was no infection, but the loosening of acetabular component was three cases. Four cases treated with arthrodesis in contralateral hip and one rheumatoid arthritis with bilateral total hip replacement were unsatisfactory to improvement of gait and A. D. L.

Review of the Total Hip Arthroplasty

We have performed the thirty-three total hip arthroplasties. We described the results of the analization of the cases. Seven of the prostheses has been of the Charnley type. Nine Charnley-Muller type, three Judet's Monobloc type and fourteen Lagrange-Letournel type have been carried out the same proccdure that described by Muller, without trochant eric osteotomy.1. The average of the operative time was 2.9 hours and the blood loss during operation was approximately 1763 gram.2. Except for the cases with infection, the temperature gradually return to normal within the third or fourth day post-operatively and the normalisation of ESR was seen within the six week.3. According to Judet's assessment method, excellent and good cases were 84% in pain, 70% in range of motion and only 40% in ability of walking.

Wear of solid phase formed high density polyethylene in relation to the life of artificial hips and knees

Factors affecting the life of ultra high molecular weight high density polyethylene (HDPE) bearing components of artificial hips and knees are discussed A programme of wear tests is described and the results are discussed in relation to the life of the HDPE acetabular cup of hip protheses and the plastic component of the Leeds knee. Under favourable conditions of moulding, HDPE has very low wear rates. On the basis of the wear coefficient of the unmoulded material it was found that the reduction in the thickness of a Charnley type acetabulum was close to results obtained from in vivo measurements. It was estimated that the rate of reduction in the thickness of the plastic component of the Leeds knee prothesis would be less than one millimetre every twenty years, which is acceptable.

Total hip replacement. First year's experience.

Developed techniques of total prosthetic replacement of diseased hip joints have led to a study of 92 patients (110 hips) who underwent total hip replacement of the Charnley type during the one-year period from October 1969 to October 1970. The majority of patients were over 60 years of age and degenerative joint disease was the largest diagnostic category. The major complications encountered were dislocation of prosthetic components (seven patients) and thromboembolic disease (three patients). No harmful effects from the use of polymethylacrylate to cement the prostheses into bone have yet been recognized. Study of the prosthetic components, technique of this procedure, and method of treatment has initiated several potentially serious questions which can only be answered by continued, long-term study.