Hip fusion in young adults.

Hip arthrodesis remains an option for treatment of severe arthritis in young persons resulting primarily from osteonecrosis, congenital dysplasia, and joint sepsis. The authors reviewed six patients who underwent fusions as young adults (average age: 30.8 years) with an average follow-up period of 11.7 years. Solid arthrodesis without infection was noted in all cases. Patients who worked returned to prior employment without limitation. All patients complained of symptomatic low back pain and felt ambulation was limited by ipsilateral knee pain. Five of six noted impaired sexual function; although childbearing was not affected in one case. Four of six were satisfied with the operation, but only three of six would undergo it again given the alternative of total joint arthroplasty.

Inhibition of associates and activation of synonyms in the rare-word paradigm: Further evidence for a center--surround mechanism.

Two experiments investigated semantic priming effects in a modified version of the Dagenbach, Carr, and Barnhardt (1990) rare-word paradigm. After learning a list of rare words to a criterion of 50% recall, subjects participated in a lexical decision task in which the rare words served as primes. When the targets were associatively related to the primes, lexical decision responses were facilitated following recalled definitions and inhibited following unrecalled definitions. When the targets were synonyms of the rare words, facilitation occurred following both recalled and unrecalled definitions. The results were interpreted as supporting a center-surround model of attentional retrieval that may serve an adaptive role in new learning.

The psychological unconscious. Found, lost, and regained.

In response to Greenwald's article on contemporary research on unconscious mental processes, the authors address three issues: (a) the independence of much recent research and theory from psychodynamic formulations; (b) the broad sweep of the psychological unconscious, including implicit perception, memory, thought, learning, and emotion; and (c) the possibility that the analytic power of unconscious processing may depend both on the manner in which mental contents are rendered unconscious and the manner in which they are to be processed.

Posterior malleolar ankle fractures: an in vitro biomechanical analysis of stability in the loaded and unloaded states.

The use of internal fixation for posterior malleolar fractures remains controversial. This study assessed the contribution of the posterior malleolus/posterior tibiofibular (PM/PTF) complex to ankle stability in the loaded condition. Total plantarflexion and dorsiflexion, torsion, version, and drawer were measured with 15- and 70-kg loads before and after creation of posterior malleolar fractures that measured 25% of the distal articular surface. After internal fixation, specimens were retested. Fractures caused significant increases with internal rotation and posterior drawer at 15- and 70-kg loads in the neutral position. External rotation, anterior drawer, and dorsiflexion increased at 15-kg load. Fixation increased stability of fractured specimens, but not significantly. Fractures of the PM/PTF ligament complex may lead to excessive internal rotation and posterior instability in the loaded state.