INTRODUCTION:A stable osseointegration of an alumina-matrix-composite-ceramic (AMC) could facilitate the use of a thin-walled monoblock acetabular cup for hip arthroplasty with large ball-heads providing advantages like reduced risk of dislocation. The aim of the pilot study was to examine the osseointegration of porous-coated alumina-matrix-composite-ceramic-monoblock cups after implantation in a sheep model.MATERIAL AND METHODS:The porous coated AMC-ceramic cups were taken out after a healing period of 8 and 52 weeks after unilateral implantation in 5 and 6 sheep, respectively. The osseointegration was analysed histomorphologically and histomorphometrically by representative serial sections after dying according to Masson-Goldner. The examination was stratified according the pole and the rim areas as a press-fit cup with an extended rim was used. Two animals had a hip dislocation after 8 weeks and these animals were excluded from the study and replaced.RESULTS:The cups were appraised as stable in the bony bed. Histologically, the rim area of the acetabular cup showed a higher osseointegration rate than the pole area. The rate of osseointegration in total was 3% after 8 weeks and 7% after 52 weeks. The rim area furnished 5.1% after 8 and 8.6% after 52 weeks. At the pole the osseointegration was 1,2% after 8 and 5.5% after 52 weeks. No significant differences were seen between both assessed time periods regarding the osseointegration rates. The bone showed an interlocking aspect with the pores of the coating as bony tissue was determined in the pores.CONCLUSION:The presented pilot study revealed a stable osseointegration of porous-coated AMC-ceramic monoblock cups one year after surgery in a weight-bearing animal model. Interlocking of bone and porous coating may provide a stable osseointegration in the presence of low osseointegration rates, whose enhancement seems to be preferable.

Herbal medicine (phytotherapy) is increasingly used by the German population. But its use for children has been rarely analysed. This study determined prevalence, motivations and indications for the use of herbal medicine use. It also investigated parent-related variables associated with its use.An anonymized questionnaire was filled in by parents of children and adolescents who attended the general pediatric out-patient department of two German university children's hospitals and the practice of two general pediatricians.413 of 600 parents (68.8%) completed the questionnaire. Mean age of the children was 6.7 +/- 4.7 years. 353 (85.5%) were given one or more herbal products, chamomile (85.5%), fennel (81.3%), eucalyptus (43.9%). Bronchipret 43.1%) (thyme and primrose [tablets] or thyme with ivy [syrup] and Prospan (43.1%) (a syrup of ivy leaf extract) were the most commonly used, in the treatment of cough. Parents who give phytotherapeuticals to their children were significantly more often women, living in a large city, of good education and financially better off (p< 0.05).Herbal medicine is widely used in Germany during childhood and adolescence. To achieve high therapeutic safety it is important to ask parents explicitly about such use.

Background and objectives: Herbal medicine (phytotherapy) is increasingly used by the German population. But its use for children has been rarely analysed. This study determined prevalence, motivations and indications for the use of herbal medicine use. It also investigated parent-related variables associated with its use.Methods: An anonymized questionnaire was filled in by parents of children and adolescents who attended the general pediatric out-patient department of two German university children's hospitals and the practice of two general pediatricians.Results: 413 of 600 parents (68.8%) completed the questionnaire. Mean age of the children was 6.7 +/- 4.7 years. 353 (85.5%) were given one or more herbal products, chamomile (85.5%), fennel (81.3%), eucalyptus (43.9%). Bronchipret (R) 43.1%) (thyme and primrose [tablets] or thyme with ivy [syrup] and Prospan (R) (43.1%) (a syrup of ivy leaf extract) were the most commonly used, in the treatment of cough. Parents who give phytotherapeuticals to their children were significantly more often women, living in a large city, of good education and financially better off (p<0.05).Conclusion: Herbal medicine is widely used in Germany during childhood and adolescence. To achieve high therapeutic safety it is important to ask parents explicitly about such use.

INTRODUCTION:The aim of this study was to analyse mechanically and histologically the osteointegration of porous-surfaced ceramic implants made of an alumina matrix composite (AMC) by assessing maximum shear strength and histomorphometric bone ongrowth. METHODS:The surfaces of the cylindrically shaped AMC test implants were characterised by a porosity of 40% and a pore size of 150 to 300 microm. A total of 24 test cylinders was implanted bilaterally into the femurs of 6 female adult Goettinger minipigs. 12 weeks after surgery the animals were sacrificed. 12 test implants were used for a push-out test and 12 test implants were evaluated histologically. RESULTS:The mean maximum shear strength of the bone-implant interface was 7.6 +/- 2.0 MPa. Direct bone attachment was found in 7.4 +/- 3.4% of the histologically analysed surfaces. CONCLUSION:In summary, porous-surfaced AMC test implants demonstrated good mechanical stability in spite of a low percentage of bone ongrowth. This discrepancy could potentially be explained by bone ingrowth into the pores and subsequent interlocking mechanisms.

The situation, described in this casuistry, shows the fatal consequences of the huge amount of wear particles from the PE-PMMA-components of a total hip prosthesis. The prosthesis had been implanted in Russia. It was made of a PE-ball fixed to a titanium stem and a socket, which had been molded intraoperatively in situ. The combination of PMMA and PE in the bearing surface caused an extrem osteolysis in the proximal femur and the acetabulum and the loosening of the cup and the stem within only a few months.

Treatment of spondylolysis and minor form of spondylolisthesis in childhood is usually conservative and includes physical therapy, a temporary reduction in sport activities or the use of an orthesis. Persisting pain despite conservative therapy, neurological symptoms and progressive sliding on x-ray may indicate surgical treatment. We report about the results in 25 patients operated by direct repair of the isthmus between 1982 and 1990 in the Orthopaedic Hospital in Mannheim. In 75% of the cases the special hook-screw by Morscher was used. The other patients were operated according to the original method described by Buck or by the Scott procedure with wire fixation. The clinical and radiological results were available in all patients by a mean follow-up of 8.9 years (4-12 years). All juvenile patients had good or very good clinical results. Within the adult group half of the patients had fair or worse clinical results. Only in 3 out of 14 cases we found bony consolidation of both arches. In 6 cases the x-ray showed pseudoarthrosis on both sides. In 3 of these patients spondylodesis had to be performed. Because of the bad results of direct repair in adult patients, we looked for further criteria, which are necessary to achieve good clinical and radiological results. In addition of the age, the condition of the disc is important. In adolescent patients (more than 16 years old) we documented a degeneration of the disc by NMR or by intraoperative discography.

Aim: This study investigated the fusion properties of a new intervertebral spacer that is directly fixed to the adjacent vertebrae by screws. The new spacer was compared with an identical spacer without direct fixation but with an additional plate and with an autologous bone graft.Methods: A single-level, cervical fusion was performed on 18 mature Merino sheep. Three treatment groups of six sheep each were used. Group A used an autogenous bone graft and an additional anterior plate. Group B used a titanium solid spacer with a titanium plasmasprayed (TPS) surface and an additional anterior plate. Group C used a similar spacer as group B that was directly fixed with the adjacent vertebrae with 4 screws. The standing period was 12 weeks. The substrates were evaluated radiographically and histologically.Results: Dislocation of the spacer or the bone graft occurred in one of the 6 cases in each group A and B, while 5 of the 6 spacers were dislocated in group C. Successful fusion was found in 4 of the 6 cases in groups A and C and in 5 of the 6 cases in group B. The histomorphometry revealed a direct bone apposition at the interface of the bone graft (group A) at 11.6% of the surface. The surfaces of the spacers were osseointegrated in 1.1 % in group B and 1.0% in group C.Discussion: As the dislocation rate shows, the fixation of the new spacer (group C) seems to be less stable than the fixation of the bone graft or the spacer with the additional plate. Although the intervertebral fusion is comparable for all groups, the extent of the osseointegration is much higher for the bone graft than for the spacers. In conclusion, the bone graft may offer a much better long-term stability than do the spacers.

AIM This study investigated the fusion properties of a new intervertebral spacer that is directly fixed to the adjacent vertebrae by screws. The new spacer was compared with an identical spacer without direct fixation but with an additional plate and with an autologous bone graft. METHODS A single-level, cervical fusion was performed on 18 mature Merino sheep. Three treatment groups of six sheep each were used. Group A used an autogenous bone graft and an additional anterior plate. Group B used a titanium solid spacer with a titanium plasma-sprayed (TPS) surface and an additional anterior plate. Group C used a similar spacer as group B that was directly fixed with the adjacent vertebrae with 4 screws. The standing period was 12 weeks. The substrates were evaluated radiographically and histologically. RESULTS Dislocation of the spacer or the bone graft occurred in one of the 6 cases in each group A and B, while 5 of the 6 spacers were dislocated in group C. Successful fusion was found in 4 of the 6 cases in groups A and C and in 5 of the 6 cases in group B. The histomorphometry revealed a direct bone apposition at the interface of the bone graft (group A) at 11.6% of the surface. The surfaces of the spacers were osseointegrated in 1.1% in group B and 1.0% in group C. DISCUSSION As the dislocation rate shows, the fixation of the new spacer (group C) seems to be less stable than the fixation of the bone graft or the spacer with the additional plate. Although the intervertebral fusion is comparable for all groups, the extent of the osseointegration is much higher for the bone graft than for the spacers. In conclusion, the bone graft may offer a much better long-term stability than do the spacers.

La mobilizzazione asettica di un’artroprotesi totale cementata dell’anca nei follow-up a lungo termine ha indotto i chirurghi ortopedici a sviluppare impianti per il fissaggio biologico non cementato. In questo capitolo vengono discussi il disegno, gli aspetti della superficie e i prerequisiti della tecnica chirurgica dell’integrazione ossea delle coppe e degli steli. Dopo la presentazione del planning preoperatorio, vengono spiegate le tecniche chirurgiche con l’uso di una coppa filettata, una coppa con inserimento a pressione e uno stelo conico

In the 1970ies cementless ceramic implants were introduced into total hip arthroplasty as monolithic ceramic screwed cups for the first time. Clinical and radiographical follow-ups revealed cup migration as a hint of instability of the implant and lack of osseointegration.

Four threaded cups were tested up to their lever-out moments, torque-in moments and their resistance to failure. A was a parabolic-shaped, B was a spherical, C was a spherical-shaped too, and D was a conical shaped cup. Cup A and D represent cups which have proven themselves in clinical applications, but not cup B. The threads were determined and showed different constructive features.The cups were torqued into precise cavities in PVC foam cubes, after that they were levered out in a testing machine.The lever-out moments of all the cups showed significant differences; the results were: A: 78.4 Nm, B: 88.7 Nm, C: 117.5 Nm, D: 136.6 Nm. In the case of the torque-in moments there were no significant differences between A and B, neither between C and D. The differences in stiffness between B and C were not significant, but they were between the others.The primary stability against lever-out and the torque-in moment of threaded cups for artificial hip replacement can be basically influenced by different constructive features. Hence lever-out moment and torque-in moment should be understood and tested as independent variables.

Four threaded cups were tested up to their lever-out moments, torque-in moments and their resistance to failure. A was a parabolic-shaped, B was a spherical, C was a spherical-shaped too, and D was a conical shaped cup. Cup A and D represent cups which have proven themselves in clinical applications, but not cup B. The threads were determined and showed different constructive features. The cups were torqued into precise cavities in PVC foam cubes, after that they were levered out in a testing machine. The lever-out moments of all the cups showed significant differences; the results were: A: 78.4 Nm, B: 88.7 Nm, C: 117.5 Nm, D; 136.6 Nm. In the case of the torque-in moments there were no significant differences between A and B, neither between C and D. The differences in stiffness between B and C were not significant, but they were between the others. The primary stability against lever-out and the torque-in moment of threaded cups for artificial hip replacement can be basically influenced by different constructive features. Hence lever-out moment and torque-in moment should be understood and tested as independent variables.

The aim of this experimental study was to screen different surface structures of alumina and zirconia ceramic implants for their osteointegration properties. Alumina and zirconia ceramic test implants having different surface structures (smooth, macro-structured, corundum-blasted, porous) were implanted in the femora of mini-pigs, and left in situ for 12 weeks. After removal, the implants were evaluated macroradiographically and histologically. The smooth and macro-structured ceramic surfaces showed virtually no bony ingrowth, neither in the cortical nor the cancellous bone areas. In contrast, a rough surface finish or a porous surface structure allowed extensive bony ingrowth. The osteointegration rates varied between 20.5% and 41.7% (cancellous bone), and between 26.0% and 52.8% (cortical bone). With regard to the development of ceramic implants for clinical use, for example in the field of total hip replacement, these data provide a basis for further, more comprehensive studies.

The aim of this experimental study was to screen different surface structures of alumina and zirconia ceramic implants for their osteointegration properties.Alumina and zirconia ceramic test implants having different surface structures (smooth, macrostructured, corundum-blasted, porous) were implanted in the femora of mini-pigs, and left in situ for 12 weeks. After removal, the implants were evaluated macroradiographically and histologically. The smooth and macro-structured ceramic surfaces showed virtually no bony ingrowth, neither in the cortical nor the cancellous bone areas.In contrast, a rough surface finish or a porous surface structure allowed extensive bony ingrowth. The osteointegration rates varied between 20.5 % and 41.7 % (cancellous bone), and between 26.0 % and 52.8 % (cortical bone).With regard to the development of ceramic implants for clinical use, for example in the field of total hip replacement, these data provide a basis for further, more comprehensive studies.

The aim of this experimental study was to screen different surface structures of alumina and zirconia ceramic implants for their osteointegration properties. Alumina and zirconia ceramic test implants having different surface structures (smooth, macro-structured, corundum-blasted, porous) were implanted in the femora of mini-pigs, and left in situ for 12 weeks. After removal, the implants were evaluated macroradiographically and histologically. The smooth and macro-structured ceramic surfaces showed virtually no bony ingrowth, neither in the cortical nor the cancellous bone areas. In contrast, a rough surface finish or a porous surface structure allowed extensive bony ingrowth. The osteointegration rates varied between 20.5 % and 41.7 % (cancellous bone), and between 26.0 % and 52.8 % (cortical bone). With regard to the development of ceramic implants for clinical use, for example in the field of total hip replacement, these data provide a basis for further, more comprehensive studies.