Iris Schleicher

Biphasic scaffolds for repair of deep osteochondral defects in a sheep model

BACKGROUND To oppose the disadvantages of autologous osteochondral transplantation in the treatment of deep osteochondral defects such as donor site morbidity, size limitation, and insufficient chondral integration, we developed two biphasic scaffolds of either hydroxylapatite/collagen (scaffold A) or allogenous sterilized bone/collagen (scaffold B) and tested their integration in a sheep model. METHODS We collected chondral biopsies from 12 sheep for the isolation of chondroblasts and cultured them for 4 wk. We created defects at the femoral condyle and implanted either scaffold A or B with chondrocytes or cell free. After 6 wk, animals were euthanized, we explanted the condyles, and evaluated them using histological, immunohistochemical, molecular biological, and histomorphometrical methods. RESULTS Specimens with scaffold A showed severe lowering of the surface, and the defect size was larger than for scaffold B. We found more immune-competent cells around scaffold A. Chondrocytes were scarcely detected on the surface of both scaffolds. Histomorphometry of the interface between scaffold and recipient showed no significant difference regarding tissue of chondral, osseous, fibrous or implant origin or tartrate-resistant acid phosphatase-positive cells. Real-time reverse transcriptase-polymerase chain reaction analysis revealed significant up-regulation for collagen II and SOX-9 messenger ribonucleic acid expression on the surface of scaffold B compared with scaffold A. CONCLUSIONS Scaffold B proved to be stable and sufficiently integrated in the short term compared with scaffold A. More extensive evaluations with scaffold B appear to be expedient.

Einfluß der arthroskopischen Therapie auf den Verlauf der Osteochondrosis dissecans des Knie- und oberen Sprunggelenks

In der vorliegenden Studie wird die Entwicklung der Osteochondrosis dissecans (OD) im Bereich 2er häufiger Lokalisationen, an den Femurkondylen des Kniegelenks und der Talusrolle des oberen Sprunggelenks, einerseits nach konservativer Therapie (40 Patienten) und andererseits nach operativer, arthroskopischer Therapie (72 Patienten) im mittelfristigen Verlauf geprüft und miteinander verglichen. Als Beurteilungskriterium wurde die MRT herangezogen, die eine enge Korrelation mit den arthroskopischen Stadien der OD aufweist. Die Stadieneinteilung in der MRT erfolgte anhand der Morphologie des sog. Grenzsaums, d. h. der Zone zwischen osteochondralem Herd und Mausbett, in der T1- und T2-gewichteten Spinechosequenz. Wesentliche Unterschiede zwischen den beiden Behandlungsgruppen bezüglich der Darstellung in der MRT zeigten sich im mittelfristigen Verlauf (18 bzw. 24 Monate) nicht. In der Mehrzahl der Fälle, (> 60%) blieb der kernspintomographische Befund trotz der durchgeführten Therapie unverändert. Die arthroskopische Behandlung führte, im Vergleich zur konservativen Therapie, in einem geringfügig höheren Prozentsatz (36% im Vergleich zu 30%) zu einer kernspintomographisch nachgewiesenen Reintegration im Sinn eines upgradings, sie konnte eine Desintegration der OD jedoch nicht in allen Fällen verhindern (4%). In beiden Behandlungsgruppen nahm das Lebensalter Einfluß auf den Verlauf der OD mit günstigeren Verläufen bei der juvenilen als bei der adulten Form.In this study the course of osteochondritis dissecans at two often affected areas, the femoral condyles of the knee joint and the talus at the upper ankle joint, is evaluated by studying and comparing the medium-term outcome in 40 patients treated conservatively and 72 patients treated surgically by arthroscopy. The criterion of assessment was magnetic resonance imaging (MRI), which shows a close correlation to the arthroscopic stages of osteochondritis. The stages on MRI follow the morphology of the interface, i.e., the zone between the osteochondral fragment and the parent bone, on T1- and T2-weighted images. After 18 and 24 months there were no substantial differences visible on MRI between the two different treatment groups. In fact, in the majority of cases (> 60%) the MRI result was the same in spite of the treatment that had been carried out. Arthroscopic treatment compared to conservative treatment resulted in a small percentage in a reintegration in the sense of upgrading on the MRI (36% to 30%); nevertheless, a disintegration could not be avoided in all cases (4%). In both treatment groups the age of the patient seems to play an important role in the course of osteochondritis, juvenile forms following a milder course than adult forms.

Examiner effect on the objective structured clinical exam - a study at five medical schools

BackgroundThe Objective Structured Clinical Examination (OSCE) is increasingly used at medical schools to assess practical competencies. To compare the outcomes of students at different medical schools, we introduced standardized OSCE stations with identical checklists.MethodsWe investigated examiner bias at standardized OSCE stations for knee- and shoulder-joint examinations, which were implemented into the surgical OSCE at five different medical schools. The checklists for the assessment consisted of part A for knowledge and performance of the skill and part B for communication and interaction with the patient. At each medical faculty, one reference examiner also scored independently to the local examiner. The scores from both examiners were compared and analysed for inter-rater reliability and correlation with the level of clinical experience. Possible gender bias was also evaluated.ResultsIn part A of the checklist, local examiners graded students higher compared to the reference examiner; in part B of the checklist, there was no trend to the findings. The inter-rater reliability was weak, and the scoring correlated only weakly with the examiner’s level of experience. Female examiners rated generally higher, but male examiners scored significantly higher if the examinee was female.ConclusionsThese findings of examiner effects, even in standardized situations, may influence outcome even when students perform equally well. Examiners need to be made aware of these biases prior to examining.

Follow up of complete subtalar release for clubfoot—Evolution of different scores

BACKGROUND Even today there are still some cases of clubfoot that require a more extensive form of treatment. Thus, it is still essential to ascertain the development of the clubfoot after extensive release operations. METHOD 70 children presenting 99 cases of primary clubfoot (age 8 months-10 years) were followed up after 4.5 and 9 years following complete subtalar release. Function, clinical and radiological results as well as 3 scores were assessed at both dates. RESULTS Function and pain worsened between the two follow-up periods, whereas objective clinical and radiological results remained equivalent. 44-79% were rated good or excellent depending on the scoring system applied.Older children with primary clubfoot had comparable results to children operated on at a younger age; also pre-operated feet achieved similar results. CONCLUSION In our opinion the results justify keeping complete release in mind as an alternative method in cases of severe residual and recurrent clubfoot.

Accuracy of navigation in hip resurfacing with different surgeons and varying anatomy

The accuracy of a commercial imageless navigation system for hip resurfacing and its reproducibility among different surgeons and for varying femoral anatomy was tested by comparing conventional and navigated implantation of the femoral component on different sawbones in a hip simulator. The position of the component was measured on postoperative radiographs. Variance for varus/valgus alignment and anteversion was higher for conventional implantation. Among the three surgeons, operation time, chosen implant size and anteversion were significantly different for conventional implantation but not for the navigated method. Using navigation, no difference was found for normal and abnormal anatomy. Values obtained with the navigation system were consistent with those measured on radiographs. Navigation appeared to be accurate and helped to reduce outliers. This was true for the three different surgeons and in varying anatomical situations.

Does quantity ensure quality? Standardized OSCE-stations for outcome-oriented evaluation of practical skills at different medical faculties

BACKGROUND Practical skills are often assessed using Objective Structured Clinical Skill Exams (OSCE). Nevertheless, in Germany, interchange and agreement between different medical faculties or a general agreement on the minimum standard for passing is lacking. METHODS We developed standardized OSCE-stations for assessing structured clinical examination of knee and shoulder joint with identical checklists and evaluation standards. These were implemented into the OSCE-course at five different medical faculties. Learning objectives for passing the stations were agreed beforehand. At each faculty, one reference examiner scored independently of the local examiner. Outcome of the students at the standardized station was compared between faculties and correlated to their total outcome at the OSCE, to their results at the Part One of the National Medical Licensing Examination as a reference test during medical studies and to their previous amount of lessons in examining joints. RESULTS Comparing the results of the reference examiner, outcome at the station differed significantly between some of the participating medical faculties. Depending on the faculty, mean total results at the knee-examination-station differed from 64.4% to 77.9% and at the shoulder-examination-station from 62.6% to 79.2%. Differences were seen in knowledge-based items and also in competencies like communication and professional manner. There was a weak correlation between outcome at the joint-examination-OSCE-station and Part One of the National Medical Licensing Examination, and a modest correlation between outcome at the joint-examination-station and total OSCE-result. Correlation to the previous amount of lessons in examining joint was also weak. CONCLUSION Although addressing approved learning objectives, different outcomes were achieved when testing a clinical skill at different medical faculties with a standardized OSCE-station. Results can be used as a tool for evaluating lessons, training and curricula at the different sites. Nevertheless, this study shows the importance of information exchange and agreement upon certain benchmarks and evaluation standards when assessing practical skills.