Mechanics of retrograde nail versus plate fixation for supracondylar femur fractures.

Two common types of internal fixations for the supracondylar femur fractures--the retrograde intramedullary nail and the 95 degrees sideplate and screw--were mechanically tested in synthetic composite femur bones to determine the quantitative differences in their inherent rigidity. The medial and lateral femoral condyles were separated by a sagittal osteotomy, and a standardized medial segmental shaft defect was created at the distal shaft. The osteotomized specimens were stabilized using one of the two implants and were tested in different modes of loading. The bending stiffness of both constructs were not significantly different in varus compression, medial bending (pure varus), and bending in flexion. The plate and screw implant was three times stiffer in lateral bending (pure valgus) and 1.2 times stiffer in valgus compression than the retrograde supracondylar nail (p < 0.01). The torsional stiffness of the plate and screw implant was significantly higher, 1.6 times that of the nail. Clinically, the most important and common cause of implant failure is varus loadings due to loss of medial cortical contact. Although the retrograde nail was less rigid in other physiologically less critical modes of loading, it had a rigidity comparable to that of the plate in varus loading. Therefore, a supracondylar nail may be considered a mechanically possible alternative to plate fixation.

Interpersonal conflict and emotions in an Iranian cultural practice: qahr and ashti.

qahr (not to be on speaking terms with someone) and ashti (to make up) represent a complex culture-specific fusion of emotional dynamics, cognitive evaluations, and behavioral tendencies, which both codes negative and "distancing" emotions and initiates a set of social actions and gestures that lead to amelioration of that emotional state. The causes, experience, and expressions of qahr and ashti were studied in the context of parent-child as well as inter-adult relationships. Of the ninety-two participants, forty-six mothers and 5 fathers (aged 25 to 52) constituted the Parent Sample, and 27 females and 14 males (aged 17 to 39) the Adult Sample. Qahr is a brief temporary rupture in the relationship of parent-child that is followed by ashti. The duration of qahr increases drastically in the inter-adult experience of qahr, yet it is a temporary rupture and not a break-up. Qahr is typically expressed in the form of a non-verbal ritualized sign system that indicates a lack of desire for any further interaction between the initiator and another person. The fusion of an emotional element of "being hurt," cognitive element of "being criticized," and being punished for "wrongdoing" constitute the core meaning of qahr for the child in her/his early experience of this cultural practice, which is internalized as an emotional-cognitive-behavioral cultural script by the child and later re-enacted in his/her relationships to siblings, parents, close relatives, and friends. Interpersonally, qahr has an expressive as well as instrumental function. Qahr is an indirect expression of a cluster of negative emotions such as hate, anger, dislike, and hurt. Qahr also evokes feelings of guilt, shame, regret, compassion, and love in others so that they are motivated to "correct" the "wrong-doing," and it sends a signal to the concerned others to intervene and bring about reconciliation. Ashti is the last stage of qahr. Ashti is reconciliation and mediation plays an important role in the process of ashti.