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An increasing number of treatment plans for individuals with attention-deficit/hyperactivity disorder (ADHD), as well as other disorders, include stimulant medication. The purpose of this study was to investigate the effects of stimulant medications on attention and impulsivity as measured by continuous performance tests (CPTs). The effect of other stimulants (e.g., caffeine, nicotine) on CPT performance was examined as well. Although various versions of the CPT were used in the studies reviewed, the research supports improvements in CPT performance with stimulant treatment. Implications for the use of CPTs in evaluating the effects of medications on attention are discussed. Also presented are implications for control of common substances like nicotine or caffeine when CPT is used and interpreted as a measure of attention.

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Lymphangiosarcoma of the pulmonary pleura was found to be the cause of persistent chylothorax in an eight-year-old, intact male golden retriever. After a two-month course of medical management, a lymphangiogram and thoracic duct ligation were performed with the objective of decreasing further effusion. At surgery, gross lung pathology was biopsied and yielded a histopathological diagnosis of pulmonary pleural lymphangiosarcoma. A relatively rare tumor, lymphangiosarcoma of the pulmonary pleura has not previously been documented as a source of chylothorax in the dog.

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To compare the fixation strengths of two arthroscopic anterior cruciate ligament reconstruction techniques, we harvested 10-mm bone-patellar tendon-bone grafts with 25-mm bone plugs from 12 fresh-frozen cadaveric knees. One knee of each pair was fixed using Acufex instruments and the two-incision technique; one knee was fixed using Arthrotek instruments and the one-incision technique. We used cannulated 9 x 25 mm Kurosaka screws for femoral and tibial tunnel fixation. All knees were mounted on the Instron Test System and were stressed to failure by recreating a pivot shift maneuver. The one-incision technique graft fixation was significantly stronger (mean failure, 695 N) than that with the two-incision technique (mean failure, 593 N). In all one-incision technique knees, either the patellar tendon graft avulsed off a bone plug or the plug broke. In five of six two-incision technique knees, the tibia bone plug pulled out around the interference screw. Patellar tendon graft length ranges from 90 to 105 mm, and the average two-incision technique tunnel length is 120 mm. The interference screw compressed the femoral bone plug into conical bone but compressed the tibial bone plug into cancellous bone in the two-incision technique, while in the one-incision technique the bone plug was compressed into cortical bone on both sides.

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Anatomical study of L4 nerve branch, L5 nerve root, and bony stock in the sacroiliac region was performed in cadaveric specimens to provide anatomical references for anterior fixation of the sacroiliac joint. At 1 cm intervals along the sacro-iliac joint, the distance to the lateral border of the L4 nerve branch (to the lumbosacral trunk) and the L5 nerve root was measured. Computed tomography scans and cadaveric sectioning of the sacro-iliac region were performed to evaluate the bony stock available for fixation and the optimal screw direction to prevent neurologic damage. At 4 cm above the pelvic brim, the L4 nerve branch was a mean distance of 23 mm medial to the sacro-iliac joint, whereas the L5 nerve root was 26 mm. At the pelvic brim, those distances decreased to 10 mm for both structures. Four centimeters cephalad to the pelvic brim, the AP dimension of Sl complex was decreased. Screws that were 1 cm medial to the Sl joint and directed posteriorly and parallel to the joint did not endanger neurologic structures. At four centimeters above the pelvic brim, there is less danger of neurologic injury; however, a decrease in sacral bony stock may affect fixation.

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Ten cadaveric sacroiliac joints were cleaned of soft tissue and analyzed to determine the average location of the sacroiliac joint on the outer table of the posterior ilium. The superior and inferior limbs of the joint were characterized according to length and width. The longitudinal axis for each limb was determined and located on the outer table of the posterior ilium. The location of the sacroiliac joint was then characterized with respect to established anatomic landmarks. The average lengths of the superior and inferior limbs were 4.4 and 5.6 cm, respectively. The width of each limb averaged 2.0 cm. The average distance from the longitudinal axis of the superior limb to the posterior superior iliac spine was 5.5 cm. The average longitudinal axis of the inferior limb was 1.2 cm superior to the inferior margin of the posterior inferior iliac spine. The angle between the two axes averaged 93 degrees.

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Irreducible lateral subtalar dislocation is associated with posterior tibialis tendon entrapment. Mulroy and Leitner have proposed conflicting theories regarding the exact mechanism of tendon entrapment. Cadaveric analysis of lateral subtalar dislocation supported Leitner's contention that tearing of the flexor retinaculum promotes posterior tibialis tendon entrapment. Retinacular disruption allowed tendon subluxation over the medial malleolus and talar head to the entrapped position. Entrapment of the flexor digitorum longus only occurred in the Leitner model. When the flexor retinaculum and deep posterior compartment fascia were preserved, the muscle failed at the musculotendinous junction. Flexor hallucis longus entrapment could not be produced in either experimental model. Plantarflexion of the great and lesser toes, noted on clinical presentation, is caused by functional lengthening of the route coursed by the flexor digitorum longus and flexor hallucis longus.

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The danger zone of the acetabulum is defined by Marvin Tile as that part of the posterior wall and column at the mid-acetabulum lying above the ischial spine. Screws inserted in the danger zone are at risk of violating the hip joint. Unfortunately, this zone is frequently used in the fixation of posterior wall and column fractures. Cadaveric studies were performed analyzing 1-cm cross-sections through the acetabulum for the purpose of studying the anatomical configuration of the danger zone. The plane of the cross-section was perpendicular to the posterior column. Each cross-section had the medial boundary of the acetabulum projected onto the posterior column. The cross-sections were then assembled to form the original acetabulum. By analyzing the projections on the posterior column, the exact configuration of the danger zone was determined. Screws placed at the margin of the danger zone and directed perpendicular to the posterior column violated the hip joint. Through analysis of the cross-sections, safe anatomic pathways were developed for screw placement. Cortical screws (4.5 mm), placed at entry points of 2 cm and 3 cm medial to the lateral acetabular margin and angled medially 45 degrees and 15 degrees, respectively, did not violate the hip joint. The angulation was respective to the perpendicular to the posterior column. In this study, the average width of the posterior column at the mid-acetabular level was 4.8 cm. Computed tomography scan of the acetabulum yielded valuable information regarding screw placement in the posterior column.(ABSTRACT TRUNCATED AT 250 WORDS)

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Acute rupture of tendons on the dorsum of the foot is rare and the diagnosis can be difficult. We present the case of a 51-year-old man who sustained an acute rupture of the tibialis anterior tendon. Pain about the medial aspect of the midfoot and ambulation with a steppage gait were the keys to formulating a correct diagnosis. The tendon was repaired primarily 10 days after injury. At his final follow-up examination 6 months after surgery, the patient was asymptomatic and ambulated with a normal gait.

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External fixation of unstable fractures of the distal radius yields satisfactory results but has a high complication rate. We studied thirty-five fractures in thirty-four patients to determine whether the results obtained with external fixation warranted it use. At a mean follow-up period of 31 months, the results of treatment were assessed by interviews and clinical and radiographic examination of both wrists. Twelve fractures had an excellent result, twelve had a good result, ten had a fair result, and one had a poor result. Radiographic results were graded excellent in ten fractures, good in thirteen, fair in five, and poor in seven. No correlation was found between the anatomical results and the clinical results or the patients' subjective ratings. Complications that were related directly to the fixation pins occurred in fourteen of the fractures. There were forty-five additional complications. The frequency of complications and the limitations of external fixation demand caution on the part of the surgeon to prevent iatrogenic morbidity, which would limit the benefits of the technique.

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We reviewed the clinical records and operative notes of 28 patients with fractures of the posterolateral tibial plateau seen at our institution from 1949 to 1982. Five of the 28 patients had chronic depressions of the posterolateral tibial plateau after initial treatment elsewhere. All five were disabled because of significant functional instability when the knee was in flexion. There were 23 acute fractures, of which 4 were initially nondisplaced and treated nonoperatively. One nonoperative patient was lost to followup; the remaining three were rated as having had good or excellent results. Nineteen patients had acute depressed fractures and were treated operatively with open reduction, elevation of the depressed area, and bone grafting, with or without internal fixation. All patients treated operatively at the time of injury were seen for followup from 24 to 145 months postoperatively, with a mean followup of 59 months. One patient was lost to followup; the other 18 were rated using both objective and subjective criteria. Seventeen (94%) achieved a final rating of excellent or good; one patient (6%) achieved a rating of fair. We have observed these fractures occurring in a younger population and producing significant disability in activities requiring a stable knee in flexion. The depressed posterolateral tibial plateau fracture is best assessed by AP, lateral, and 45 degrees internal oblique views on radiographic examination. Because of continued disability caused by chronic, depressed fractures of this type, we recommend open reduction and bone grafting in acute cases to eliminate instability in flexion. This procedure produces good or excellent results in most cases.

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Although the acromioclavicular joint is frequently injured in both contact and noncontact sports, the treatment is nonspecific, as demonstrated by the numerous methods of treatment currently employed. Despite treatment, some shoulders still develop chronic symptoms and disability during overhead lifting, throwing, and swinging. Perhaps these difficulties develop as a result of an incomplete evaluation of the joint and because the exact nature of the injury is not appreciated. Therefore, the shoulder develops chronic problems. We have routinely utilized a lateral roentgenogram of the acromion to evaluate the acromioclavicular joint. This has significantly aided us in the diagnosis and treatment of acromioclavicular joint injuries, especially when there was posterior dislocation of the distal clavicle. This presentation reviews standard roentgenography of the acromioclavicular joint and illustrates the method of obtaining the lateral projection as described by O. M. Alexander. We will also show how this method has helped us clinically in detecting posterior dislocations of the distal end of the clavicle.

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An analysis of 1004 X-rays has demonstrated that the medial patella facet is significantly smaller in patients with patellofemoral instability. There is no such significant difference in the width of the whole patella. Therefore the longitudinal ridge separating the smaller medial facet from the larger lateral facet must be closer to the medial patella border. As this ridge articulates with the groove between the femoral condyles, its medial position is accounted for by the patella being more laterally positioned in patients with patellofemoral instability.

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