Introduction. In Mid-Europe developmental dysplasia of the hip (DDH) is diagnosed using the sonographic hip screening described by Graf. To learn the necessary standards three courses are mandatory. However, little is known about learning curves and measurement errors of doctors at different levels of training and experience.

Material and Methods. Between 1997 and 2002 participants of the basic, advanced and final hip ultrasonogra-phy course were evaluated by a questionnaire and 34 normal and pathological sonograms. They were asked to measure the alpha and beta angle. “Normal” angles of each hip were created through the mean values of two experienced course organizers.

Results. 186 doctors (40% orthopedic surgeons, 60% pediatricians) were evaluated. The group included 20% interns, 60% residents and 20% consultants. An average time of 6.3 months lay between the basic and the advanced, and of 16.7 months between the advanced and the final course. The evaluation of the sonograms according to Graf showed major inter-observer differences of up to 30°. Participants had more difficulties in evaluating a correct beta angle than an alpha angle. Sonographic pictures of minor quality and pathological hips produced more difficulties than pictures of Graf type I and II hips. In the basic course all measurements showed an average difference of 3,6°, in the advanced course of 3,1° and in the final course of 4,2°. The number of examinations between courses did not correlate with good measurements.

Conclusion. Even participants of all three courses seem to develop major systemic errors if ultrasonography is regularly applied without supervision. Therefore, regular training and supervision should be mandatory in order to guarantee good quality.

Introduction: Hemiplegic cerebral palsy (CP) children are often treated with ankle-foot orthoses (AFO′s) in order to resist abnormal motion patterns and to restore normal function. It has been shown that AFOs are successful in improving pre-positioning of the foot for initial heel strike in CP patients. The myoelectric signal (EMG) during gait provides valuable information with respect to timing of muscular activity. The aim of this study was to evaluate changes in timing of muscle activation in children with hemipelegic CP during gait with and without wearing AFOs.

Patients/Materials and Methods: Eight Children (5 boys, 3 girls; mean age 9.5±1.4 years) with mild to moderate hemiplegic CP and no prior surgeries or fixed contractures were studied. The children were tested barefoot and wearing a hinged AFO and shoes. Only children with an initial toe-strike barefoot and a physiological heel-strike with the AFO were included. All children performed a 3-dimensional gait analysis. At least six trials with clear forceplate data have to be collected for each of the two testing condition. Frontal and sagittal video recording took place. A sSurface EMG of vastus medialis/lateralis, rectus femoris, biceps fem-oris, semimembranosus/semitendinosus, gastrocnemius lateralis (only barefoot), and tibialis anterior was collected.

Results: Mean ankle plantarflexion at initial foot contact was 16.1° when walking barefoot and 3.4° with the AFO. EMG data showed reduced tibialis anterior muscle activity with the AFO in all patients, especially in early to mid swing phase. Muscle activation pattern was corrected towards normal for knee extensors and hamstrings.

Discussion: Our results show that tibialis anterior muscle activity is reduced by a hinged AFO with plantarflexion block in hemiplegic CP children. These results indicate that the pathological muscle activation pattern present in CP patients are not only due to spastic activation but also to a compensation for the abnormal gait pattern.