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PubMedDate not supplied

Five-year report on partial ossicular replacement prostheses and total ossicular replacement prostheses.

Although much progress has been achieved in the functional restoration of ears damaged by chronic suppurative otitis media since the introduction of tympanoplasty 30 years ago, adequate hearing improvements in ears with loss of the stapedial arch have been the most elusive. It is now recognized that such ears present the surgeon with numerous associated problems that require control for a satisfactory outcome; the problem of establishing an efficient link between the tympanic membrane and oval window has proved the most difficult. The introduction of biocompatible materials was heralded as a possible solution. In order to evaluate the claims for these new materials, the five-year results obtained with one of these, porous polyethylene, were evaluated. The one-year success rate with partial ossicular replacement prostheses was 64%; the five-year success rate was 43%. With total ossicular replacement prostheses the success rate was 59% at one year and 22% at five years. These poor results, coupled with evidence of digestion of porous polyethylene, give little justification for the continued use of this material in tympanoplasty.

Ear Ossicles↗
PubMed1978

[Diagnosis for the localization of cemented intramedullar stem prostheses and ICLH-prostheses of the hip by means of stereo X-ray prints (author's transl)].

It is known that the loosening of artificial hip joints leads to their shift relative to the carrying bone structure. For a quantitative radiological detection of even minimal dislocations fix-points both in the carrying bone structure as well as in the prostheses have to be defined. While for the stem prostheses and cups such points can be defined directly from their geometrical structure, they have to be generated artificially for the carrying bone structure by implanted metal pins, which can easily be detected in the X-ray print. Having defined in this way a complete and appropriate set of fix-points, the position of the prosthesis relative to the bone structure is uniquely defined by the distance vectors between the different fix-points. The main biometrical steps of such a concept as well as their computational formulation and realization are derived; the main advantages and the accuracy of the technique are elucidated and critically discussed.

Biomechanical Phenomena↗
PubMed1998

[Ankle prostheses. Mid-term results after Thompson-Richards and STAR prostheses].

Thirty-seven patients with 20 cemented Thompson-Richards prostheses and 19 cementless S.T.A.R. prostheses (2 bilateral cases) were followed up after 1-12 years. Rheumatoid arthritis was the main diagnosis in both populations, with females dominating. The investigation was based on the Kofoed ankle score. At follow-up the total scoring improved to 86.9 pts. in S.T.A.R. and to 77.7 pts. in T.R.P. replacement. The radiological examination showed a high rate of radiolucency for the tibial component (53.3%) in cemented T.R.P.; subsidence of talar component was seen in 3 cases with T.R.P. In cementless S.T.A.R. prothesis only 3 cases showed small radiolucent lines of the flat tibial component. Talar subsidence was not seen at all. In T.R.P. we had two revisions due to prothesis loosening and one maleollar fracture, giving a cumulative estimated survival rate of 87% at 12 years. In the S.T.A.R. prosthesis group two revisions had to be performed because of one meniscal breakage and correction of meniscal height. The estimated survival rate at 6 years was 94.3%.

Ankle Joint↗
PubMed1996

Follow up and maintenance of implant supported prostheses: a comparison of 20 complete mandibular overdentures and 20 complete mandibular fixed cantilever prostheses.

Two independently selected groups of 20 patients who were edentulous in te mandible, were followed up on a regular basis over a 5-year period following restoration with a lower implant stabilised prosthesis and conventional upper denture. Significantly more treatment was required by those who received complete mandibular overdentures than those provided with complete fixed mandibular prostheses. In addition to adjustment for the relief of denture trauma to the mucosa, more mechanical problems arose with overdenture implant prostheses.

Dental Abutments↗
PubMed2000

Hearing results in pediatric patients with chronic otitis media after ossicular reconstruction with partial ossicular replacement prostheses and total ossicular replacement prostheses.

OBJECTIVE: To examine hearing results in pediatric patients after ossicular reconstruction with partial ossicular replacement prostheses (PORPs) and total ossicular replacement prostheses (TORPs) in children with chronic otitis media. METHODS: A retrospective chart review was performed on 55 pediatric patients with chronic otitis media who underwent ossicular reconstruction from 1991 to 1998. Patients' audiograms were evaluated preoperatively and postoperatively for pure-tone average (PTA), air-bone gap (ABG), speech reception threshold (SRT), method of ossicular reconstruction, and management of the mastoid. RESULTS: Twenty-seven patients underwent ossicular reconstruction with TORPs. The average preoperative ABG was 40.1 dB, and the average postoperative ABG was 31.6 dB. Forty-one percent of the children improved their PTA greater than 10 dB postoperatively, and 52% of children did not change their ABG by more than 10 dB postoperatively. Nineteen percent of children with TORPs had a postoperative ABG less than 20 dB, and 44% of children with TORPs had a postoperative ABG less than 30 dB. Twenty-eight patients underwent ossicular reconstruction with PORPs. The average preoperative ABG was 29.7 dB, and the average postoperative ABG was 22.5 dB. Thirty-two percent of patients improved their PTA by greater than 10 dB, while 57% of children with PORPs did not change their ABG by more than 10 dB postoperatively. Forty-three percent of children with PORPs had an ABG of less than 20 dB postoperatively, and 71% of children with PORPs had a postoperative ABG less than or equal to 30 dB. CONCLUSIONS: Children who underwent ossicular reconstruction with PORPs had slightly better postoperative hearing than did children with TORPs. Postoperative hearing was essentially unchanged in approximately 55% of both groups. Preoperative hearing levels may be the most important factor determining postoperative hearing in nonstaged surgery for children with chronic otitis media Long-term hearing results in children with single-stage surgery were not as good as those reported in the literature for staged surgery. Severe mucosal disease and eustachian tube dysfunction may contribute to poorer hearing results in children.

Audiometry, Pure-Tone↗
PubMed1979

[A study of the potential corrosion of the madreporic prostheses compared with plane surface prostheses (author's transl)].

The authors have studied several methods of obtaining self-locking of hip prostheses without cement. They have selected a particular type of prosthesis with a "madreporic" surface and have studied the potential danger or corrosion in such types of prosthesis as compared with prostheses with a plane surface. They have demonstrated that, in madreporic types, the surface of the prosthesis is multiplied less than four times and that this is not dangerous provided that the metal alloy is of good quality. The methods of calculation of the surface area are described as well as experiments for testing for corrosion. These methods can be applied to other types of prosthesis.

Alloys↗
PubMed1989

An analysis of the changes in the surfaces of metallic femoral components in hip prostheses. A study of 60 prostheses removed after 1-20 years.

A study of 60 femoral prosthetic components removed after 1-20 years allowed us to study the behaviour of the metallic surface in real life conditions. Changes were observed exclusively in cemented prostheses. They consisted of corrosion phenomena characteristic of the components of steel EN 58 J and 316 S, and wear phenomena secondary to mobilisation. The latter were observed in steel components as well as in those in Co-Cr alloy. The areas of corrosion in the steel prostheses were characteristically distributed, indicating a combination of causal factors, including an insufficient capacity of passivation of the metal and the particular situation of the cement-to-metal interface.

Chromium Alloys↗
PubMed1992

Results of reaugmentation with MISTI prostheses after failure of smooth silicone prostheses.

In 1988 and 1989, we replaced smooth silicone double-lumen implants with Molecular Impact Surface Textured Implants (MISTIs) in 28 of our patients. Of these, 20 had experienced recurrent capsular contracture and sought an alternative prosthesis that would provide long-term relief from this problem, and 8 simply wanted larger prostheses. Among the reaugmentation patients who had experienced recurrent contractures, 4 have had problems with the texturized implants; 1 developed an infection, and 3 developed unilateral fibrosis within weeks of surgery. The infection was resolved with antibiotics, and the fibrosis was resolved with capsulectomy, biweekly methylprednisolone irrigation in the surgical pocket, and lenticular suction drainage over a 3-week period. After a 2-year follow-up, these 4 problematic patients have remained soft and asymptomatic following their treatment, and the remaining 16 patients have remained soft and asymptomatic since their surgery.

Adult↗
PubMed1983

Polyester prostheses as substitutes in the thoracic aorta of dogs. I. Evaluation of commercial prostheses.

Using canine models, a representative selection of polyester or Dacron vascular prostheses, including woven, knitted, and velour types, were evaluated for their relative healing characteristics and for their structural changes during implantation. Following residence periods ranging from 4 h to 6 months at the site of the thoracic aorta, the dogs were sacraficed, and the grafts were excized for measurement of the thrombogenicity of the flow surface and for pathological examination by light microscopy and SEM. The kidneys were also removed and examined for infarcts caused by any trapped circulating emboli. The extent of healing, the presence of embolizing nuclei, and the thrombogenicity and morphology of the lumen surface were also assessed. The healing characteristics of each type of device proved similar. Velour fabrics exhibited more extensive encapsulation, but frequently their internal capsules failed to incorporate all the fibers. In all cases, cellular development on the lumen was limited to areas contiguous to the anastomoses. The initial porosity of the devices as measured by water permeability did not appear to influence the healing sequence to a significant extent. The grafts did exhibit differences in structural stability depending on whether they were of a knitted or woven construction. We suggest that users consider these different mechanical and structural properties when making their choice of a graft. Despite these differences, we believe that the healing process is far more host dependent than graft dependent.

Angiography↗
PubMed1991

Measurement of oral status and treatment need among subjects with dental prostheses: are the measures less reliable than the prostheses? Part I: Oral status in removable prosthodontics.

Indices used to measure the oral status of removable dental prostheses generally do not conform to criteria essential to high-quality measures. Existing indices fail to meet accepted standards of reliability and validity, and most lack specified training protocols, use ambiguous terminology, are limited to nominal, ordinal, or dichotomous level data, and require high levels of observer inference. As a result it is virtually impossible to compare one study with another, to combine data from more than one study to broaden the results obtained, and even to collect longitudinal data without being able to rule out examiner drift. More successful measures, in particular for vertical dimension of occlusion, maxillary denture retention, and arch size and shape, hold promise for future developments in research data collection and quality assessment. These improvements, combined with a growing awareness of the importance of measuring nondental factors, should lead to more reliable, valid measures of need for treatment.

Denture, Complete↗
PubMed1993

Doppler haemodynamic assessment of clinically and echocardiographically normal mitral and aortic Allcarbon valve prostheses. Valve Prostheses Ligurian Cooperative Doppler Study.

Doppler echocardiographic characteristics of normally functioning Allcarbon prostheses were studied in 149 consecutive patients with 157 valves in the mitral (n = 73) and aortic (n = 84) positions whose function was considered normal by clinical and echocardiographic evaluation. In the mitral position, the mean gradient and the effective mitral orifice area were not significantly different in either the 25-mm or the 31-mm size valves (from 5 +/- 1 to 4 +/- 1 mmHg and from 2.2 +/- 0.6 to 2.8 +/- 0.9 cm2, respectively; P = ns for both). Conversely, peak gradient was significantly and inversely correlated to actual orifice area (r = -0.70; P < 0.0006), decreasing from 15 +/- 3 mmHg in the 25-mm size valve to 9 +/- 1 mmHg in the 31-mm size. In the aortic position, the mean gradient was 29 +/- 8 mmHg in the 19-mm size valve; it decreased to 8 +/- 2 mmHg in the 29-mm size. Effective prosthetic aortic valve area, calculated using the continuity equation, ranged between 0.9 +/- 0.1 cm2 for the 19-mm size valve to 4.1 +/- 0.7 cm2 for the 29-mm size. By analysis of variance, effective prosthetic aortic valve area differentiated various valve sizes (F = 25.3; P < 0.0001) better than peak (F = 5.34; P = 0.012) or mean (F = 4.34; P = 0.0052) gradients alone, and it correlated better with actual orifice area (r = 0.89, r = -0.70 and r = -0.65, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Two-year outcome of hydroxyapatite-coated prostheses. Two femoral prostheses retrieved at autopsy.

We performed a histological study of the bone-implant interface on 2 human femurs implanted with a hydroxyapatite-coated self-locking stem for 2 years. Extensive bone formation with no intervening fibrous tissue was noted around the entire circumference of the 2 prostheses. The newly-formed bone had 2 morphotypes: an alveolar disposition with a continuous contact between bone and hydroxyapatite, and a digitiform one where distinct bony trabeculae were in contact with the ceramic coating or with the bone marrow. Partial or even total resorption of the hydroxyapatite coating was clearly identified, these areas showing bone in contact with the metal.

Aged↗
PubMedDate not supplied

[Complications after implantation of a modular total hip prostheses compared with fixed head prostheses].

164 total hip prostheses of different manufacturers were implanted over an 8-year period. Clinical records were evaluated with a complication rate of 29.0% (42 of 145 joints) or 31.7% (39 of 123 dogs). The complications encountered in dogs that received the modular hip prosthesis (Biomécanique, Bretigny-sur-orge, France) amounted to 16.3% (15 of 92), dogs that received a fixed head prosthesis (5 different manufactures) had 39% complications (28 of 72). Although the complication rate was influenced by different surgeons (n = 5) with different system predelictions and a different learning curve it was obvious that luxations (n = 6 of 10) and stem fractures (n = 5) more often occurred with the fixed head prosthesis systems. These stem fractures might be due to implant material failure or due to improper cementation followed by fatigue material failure. Femur fracture or infection were encountered with both prosthesis systems.

Animals↗
PubMed1991

[Failures of knee joint prostheses. An analysis of knee prostheses and component revisions, 1980-1987].

Total knee arthroplasty has become more common in the last 20 years as a result of the continuous improvement in prosthetic design and operative techniques. Therefore, there have also been more failures. To show the reasons for these failures and the difficulties and results of revision surgery we studied the 48 uni- or tricompartmental revisions of total knee arthroplasties we performed in our institute between 1980 and 1987. Twelve to 94 months (mean 40.4) after revision we found 66% good or very good results. The main reason for failure was a poor surgical technique, which we found in 69% in unicompartmental, and in 28% in tricompartmental prostheses. Revision surgery needs a high level of practical knowledge and flexibility. The main problems consist of correction of the alignment and the filling of bone defects. Thus, we reconstructed ten large defects at the tibial plateau, which resulted in one very good, seven good and two moderate results.

Aged↗
PubMed1987

[Rupture of the anterior cruciate ligament: a frequently unrecognized cause of failure of unicompartmental knee prostheses. Apropos of a series of 79 Lotus prostheses with a follow-up of more than 5 years].

Out of 386 unicompartmental prostheses inserted in the Orthopaedic Centre in Dracy Le Fort between 1977 and 1986, 79 cases in 68 patients with a follow-up equal to or more than five years and a mean of seven years were able to be reviewed. This study showed that 75 per cent of knees had a satisfactory result and 25 per cent were failures. Apart from well-recognised causes of failure such as rheumatoid arthritis, overcorrection or the use of a six millimetre tibial plateau, the authors discovered a frequent cause not clearly recorded in the literature--that is anterior cruciate laxity. This situation was found retrospectively in the pre-operative weight-bearing radiographs. Out of 15 knees showing a pre-operative laxity equal to or greater than 10 mm in the lateral radiograph, 13 were failures and 10 were operated on again after a mean of three-and-a-half years. An investigation of anterior cruciate laxity should be made systematically by weight-bearing lateral radiographs, if necessary with stress views, before recommending a unicompartmental prosthesis.

Aged↗
PubMed1983

[Sound spectrographic studies in the diagnosis of dysfunctions of mechanical heart valve prostheses (Björk-Shiley prostheses)].

A newly developed real-time sound spectroanalyzer was found to be capable of diagnosing malfunction of prosthetic heart valves (Björk-Shiley prostheses). Sound spectroanalysis was carried out 430 times on 257 patients with a prosthetic heart valve. The valvular click of prosthetic heart valves shows a typical sound spectroanalysis pattern in real time, with a high-frequency peak which diminishes beyond 25 kHz. Thrombosis of the prosthetic heart valve causes loss of the valvular click and reduction in the intensity of the high-frequency components, as shown in 4 patients. Thus the sound spectroanalysis appears to be a noninvasive technique which may allow early diagnosis of a thrombosed prosthetic heart valve. We believe this method to be superior to phonocardiography and echocardiography.

Aortic Valve↗