Autophor cementless total hip arthroplasty for osteoarthrosis secondary to congenital hip dysplasia

Long-term results of cementless hip arthroplasty with ceramic-on-ceramic articulation

PURPOSE

The goal of the study was to evaluate long-term results of hip arthroplasty in patients with ceramic-on-ceramic articulation.

METHODS

The follow-up involved 220 primary total hip arthroplasty procedures (188 patients, 101 women and 87 men) after implantation of the Mittelmeier cementless hip endoprosthesis. The mean age of patients at surgery was 44.5 years and the mean follow-up was 19.6 years, with a minimum of 12.3 years. Dysplastic, idiopathic and post-traumatic coxarthrosis were the most frequent forms of degenerative hip changes. The Merle d'Aubigné and Postel classification, as modified by Charnley, was used for clinical evaluation.

RESULTS

Very good results were obtained in 39.5 % of the patients, good results in 43.6 %, satisfactory results in 9.1 % and poor results in 7.8 %. Twelve-year survival for the whole prosthesis was 86.36 %, for the acetabulum 89.99 % and for the stem 91.36 %.

CONCLUSIONS

Long-term results of hip arthroplasty using the Mittelmeier prosthesis are fairly encouraging with their low incidence of loosened prosthesis components after surgery.

The Eftekhar and Kerboul classifications in assessment of developmental dysplasia of the hip in adult patients. Measurement of inter- and intraobserver reliability

AIM

To measure the inter- and intraobserver reliability of two radiologic classification systems in the evaluation of severity of osteoarthritis secondary to developmental dysplasia of the hip in adult patients and to compare these systems to historically published data on two more commonly used classification systems described by Crowe and by Hartofikakidis.

MATERIAL AND METHODS

Eighty-six dysplastic hips on 66 anteroposterior standard pelvic x-rays were rated according to the criteria of Eftekhar and Kerboul by three observers with different levels of clinical training. To assess intraobserver reliability, the measurement was repeated 3 months later. Statistical analysis was performed by calculating the weighted kappa correlation coefficient and the overall kappa coefficient.

RESULTS

Both classification systems showed a sufficient interobsever reliability, reaching a kappa coefficient of 0.73 for the system according to Eftekhar and 0.716 for the Kerboul classification system. Intraobserver reliability revealed a kappa coefficient of 0.778 for the Eftekhar system and 0.697 for the classification according to Kerboul.

CONCLUSION

Both systems showed good inter- and intraobserver reliability for use in daily practice. However, they did not reach the known reliability of the grading systems published by Crowe and by Hartofikakidis. Because these systems are more frequently used, we would recommend one of them to grade the severity of osteoarthritis secondary to developmental dysplasia of the hip in adult patients instead of the ones described by Eftekhar or by Kerboul.

The S-ROM stem and its use with alternative bearings

Many long-term studies of total hip arthroplasty (THA) show excellent results. This long-term success depends on many factors, including implant fixation and bearing surface wear. As THA is commonly performed on patients with a steadily increasing life span and activity level, the issue of wear has become critical. Advances in the wear properties of polyethylene have been significant, but, in the search for low long-term wear rates, hard bearing surfaces are frequently used.

Primary total-hip arthroplasty with the autophor 900-s fully porous coated stem in young patients seven to seventeen years of follow-up

A total of 233 Autophor 900-S fully porous coated stems were implanted in 220 patients with an average age of 47.5 years and an average follow-up of 13.5 years. The mean d' Aubigne-Postel score improved from 7.9 points preoperatively to 16.9 points postoperatively (P < .001). The overall result was excellent in 74.6%, good in 18.1%, fair in 5.8%, and poor in 1.5% of cases. One hip was revised for septic and two for aseptic loosening. The overall survival rate of this prosthesis was 98.1% in 17 years. The Autophor 900-S femoral stem has offered a very satisfactory clinical outcome together with considerable prosthesis longevity in the young patient population studied. It combines adequate initial stability, satisfactory subsequent bone ingrowth, smooth load transfer, and low-friction bearing surfaces.

Debris from failed ceramic-on-ceramic and ceramic-on-polyethylene hip prostheses

To compare the properties of wear debris between ceramic-on-ceramic and ceramic-on-polyethylene total hip prostheses, particles were isolated and characterized from tissue biopsies obtained at revision arthroplasty or autopsy from two similar uncemented modular hip systems. Group A hips (11 patients; mean, 31 months in vivo) had titanium shells with alumina inserts, alumina femoral heads, and titanium alloy stems. Group B hips (seven patients; mean, 42 months) were the same as Group A but with polyethylene acetabular inserts. Particles were characterized using an electrical resistance particle analyzer, scanning electron microscope, and energy dispersive xray spectroscope. Most of the particles in Group A were ceramic, whereas most of the particles in Group B were polyethylene. Metal particles from the femoral stem and the acetabular shell also were present. If one Group A hip with impingement is excluded, the rate of particle production is significantly lower in the ceramic-on-ceramic group than in the ceramic-on-polyethylene group. With the number of samples available, no significant difference in average size could be detected among the different types of particles or among the groups.

Ceramic/ceramic total hip arthroplasty

Alumina-on-alumina total hip arthroplasty has been used for 30 years, mainly in Europe. The theoretical advantages of this combination are represented by its remarkable sliding characteristics, its very low wear debris generation, and its sufficient fracture toughness. These advantages are achieved if the material is properly controlled with high density, high purity, and small grains. The authors summarize the results obtained with ceramic/ceramic total hip arthroplasty. Information is provided about in vivo behavior regarding wear debris characterization and quantification, and histological tissue examinations for inflammatory reactions, which were not encountered except when alumina debris was mixed with metal or cement. Modification of socket fixation resulted in improved clinical outcomes. With a press-fit metal shell and an alumina liner utilized for 10 years, the results are excellent especially in a young and active population. Alumina-on-alumina seems at the moment to be one of the best choices when a total hip arthroplasty has to be performed in young and active patients.

Evolution of alumina-on-alumina implants: a review

The use of alumina-on-alumina sliding surfaces for total hip replacement is becoming increasingly popular. The author has reviewed the 30-year history of this material. Technical aspects such as the quality of the material, quality of the design, and the risk of fracture are presented. The clinical results observed by the author are summarized with additional references to the results of other surgeons. The overall conclusion is that this material is very safe if all the quality requirements are met. The extremely low generation of wear debris and the excellent biologic tolerance of the material impart a long lifetime to the implant in young and active patients.

Medial protrusio technique for placement of a porous-coated, hemispherical acetabular component without cement in a total hip arthroplasty in patients who have acetabular dysplasia

Twenty-four hip replacements were performed with use of a medial protrusio technique to stabilize the fit of a hemispherical metal shell in the acetabulum in nineteen patients who had dysplasia of the hip. All of the hips were followed for a minimum of five years (average, seven years; range, five to thirteen years). Six of the hips were type I, seven were type II, eight were type III, and three were type IV according to the criteria of Crowe et al. The acetabular cup was implanted with the medial aspect of its dome beyond the Kohler line (drawn from the ischium along the ilioischial line) in all hips. An autogenous graft sculpted from the femoral head was used to cover 15 to 30 percent of the superolateral portion of the cup in one type-I hip, four type-III hips, and one type-IV hip. The need for these six bone grafts could have been avoided by reaming two to three millimeters more medially or by allowing 20 percent of the superolateral portion of the cup to be uncovered. Sixty to 84 percent of each bone graft was resorbed, effectively leaving the superolateral portion of the cup uncovered. The amount of the surface of the cup that was beyond the Kohler line averaged 41 percent for the six type-I hips, 43 percent for the seven type-II hips, 41 percent for six of the type-III hips, and 44 percent for one of the type-IV hips. Crossing of the ilioischial and iliopubic lines was noted on the radiographs of two type-III and two type-IV hips. Radiographs of two type-I hips and one type-II hip showed 7 to 17 percent of the surface of the dome of the cup through the internal pelvic wall (beyond the iliopubic line). None of the twenty-four metal shells were revised. A reoperation was performed on two hips to exchange a worn polyethylene insert, and three femoral components that had been fixed without cement were revised because of mechanical loosening. Wear averaged 0.26 millimeter per year in the fourteen hips that had a titanium femoral head and 0.09 millimeter per year in the nine hips that had a cobalt-chromium femoral head. The remaining hip had a ceramic femoral head, and the wear rate was 0.09 millimeter per year. The medial protrusio technique is a predictable, reproducible method for obtaining fixation of a porous-coated, hemispherical acetabular component in a dysplastic acetabulum. The technique permits the use of a porous-coated (bone-ingrowth) component; avoids the use of support bone graft and thereby reduces the operative time; facilitates rehabilitation by permitting earlier weight-bearing of the hip; and permits the use of a modular bearing surface, which may allow future exchange of only this surface rather than revision of the entire acetabular component because of excessive wear.