Bilateral congenital absence of the patella in an adult: case report

Bilaterally absent patella is a rare clinical entity. Most documented cases occur in association with Nail- Patella Syndrome. This patient presented at 60 years of age with severe bilateral knee arthritis and was found to have bilaterally absent patella which had previously been undiagnosed. The patient was managed with bilateral knee replacements. This presentation highlights the need for vigilance of the condition in patients presenting with knee arthritis.Key words: Congenital absence patella knee arthroplast

Normal values of hertel exophthalmometry in children, teenagers, and adults from Tehran, Iran

PURPOSE.: The aim of this study was to present normative values of exophthalmometry in Iranian children, teenagers, and adults and find the effect of age, gender, height, weight, and laterality (right vs. left eye) on normal values of protrusion. METHODS.: In a population-based epidemiological study, ocular protrusion values (mm) were measured in 1063 randomly selected (stratified sampling method) normal subjects using the Hertel exophthalmometer. Weight and height were measured in all subjects. RESULTS.: There were 462 (43.5) females and 601 (56.5) males. The age ranged from 6 to 70 years (mean ± SD = 20.3 ± 10.9). Subjects were divided into three age groups (years); children (range: 6 to 12, mean: 9.2 ± 1.6), teenagers (range: 13 to 19, mean: 15 ± 1.4), and adults (range: 20 to 70, mean: 31 ± 7.9). The mean (±SD) absolute ocular protrusion value was 14.2 ± 1.8 in children, 15.2 ± 1.9 for teenagers, and 14.7 ± 2.3 for adults. Right and left eye protrusions were well correlated (r = 0.97, p < 0.0005 in children and adults and r = 0.95, p < 0.0005 in teenagers). However, right eye protrusion was significantly more than on the left side (p < 0.0005). Although males had more eye protrusion, the gender difference was not significant except for teenagers. Weight and height did not have a significant effect on eye protrusion. No individual had more than 2 mm of asymmetry (relative eye protrusion). Increasing age had a significant effect on the eye protrusion (r = +0.32 for children, r = +0.13 for teenagers, and r = -0.30 for adults; 0.001 < p < 0.0005). The ocular protrusion was positively correlated with increasing distance between the two lateral orbital rims (base) in all age groups (p < 0.0005). CONCLUSIONS.: Any eye protrusion of more than 17.8 mm for Iranian children, 19 mm for Iranian teenagers, and 19.3 mm for Iranian adults and relative eye protrusion of more than 2 mm warrants further clinical examination. Age and base value had a significant impact on normal eye protrusion values. © 2008 American Academy of Optometry

Robust projective lag synchronization in drive-response dynamical networks via adaptive control

This paper investigates the problem of projective lag synchronization behavior in drive-response dynamical networks (DRDNs) with identical and non-identical nodes. An adaptive control method is designed to achieve projective lag synchronization with fully unknown parameters and unknown bounded disturbances. These parameters were estimated by adaptive laws obtained by Lyapunov stability theory. Furthermore, sufficient conditions for synchronization are derived analytically using the Lyapunov stability theory and adaptive control. In addition, the unknown bounded disturbances are also overcome by the proposed control. Finally, analytical results show that the states of the dynamical network with non-delayed coupling can be asymptotically synchronized onto a desired scaling factor under the designed controller. Simulation results show the effectiveness of the proposed method