Safe screw placement in acetabular revision surgery.

Revision of an acetabular component with extensive bone loss is a procedure that sometimes includes allografting or the placement of an unusually sized or positioned uncemented acetabular component. We evaluated the quadrant system used to guide screw placement in primary uncemented total hip surgery in the high hip center, jumbo component, and 3 designs of reinforcement rings. We used 14 pairs of cadaver hemipelves, which were prepared by removing all soft tissues except the medial neurovascular structures. With each implant, all screw holes were tested to determine if they followed the safe quadrant recommendations. In the high hip center, the center and anterior of the superoposterior quadrant was dangerous. All of the other implants met the quadrant recommendations.

A modified internal rotation stretching technique for overhand and throwing athletes.

Strength, stretching, and rehabilitation methods for the shoulder have been previously described and have been universally applied; nevertheless, many throwing athletes continue to develop overuse injuries. The pitching process tends to increase external rotation and limit internal rotation of the shoulder joint. Our technique involves a modified stretching method of the posterior shoulder musculature. The athlete lies prone with the elbow flexed 90 degrees. With the shoulder abducted 90 degrees, in neutral flexion/extension, and 90 degrees or more of internal rotation, the scapula protrudes posteriorly. By depressing the inferior angle of the scapula toward the thoracic wall, the infraspinatus muscle and posterior joint capsule are effectively isolated and stretched. Manual stabilization of the scapula onto the chest wall transfers the internal rotation movements to the glenohumeral joint, as opposed to sharing the movement with the scapulothoracic articulation. This method improves the efficacy of the internal rotation stretching exercise for the glenohumeral joint. Such an addition to traditional stretching methods may increase the efficiency of the least effective component. We conclude that this modification to traditional programs should be an integral part of the training and rehabilitation program of any athlete requiring near maximal performance of the shoulder.

Effects of gossypol on the hepatic drug metabolizing system in rats.

Gossypol, a polyphenolic pigment found in cotton plants, has been implicated as an antifertility agent. This pigment has been shown to alter myriad metabolic pathways. The objective of this study was to determine the effect of gossypol acetic acid on the hepatic microsomal drug metabolizing enzyme system in adult female Fisher 344 rats. Subcutaneous administration in both low (15 mg/kg) and high (30 mg/kg) doses of gossypol acetic acid for five consecutive days significantly (P less than 0.00001) reduced hepatic aniline hydroxylase activity, as well as cytochrome P-450 and b5 levels. Thus, compared to the controls, the low doses of gossypol decreased the hepatic aniline hydroxylase activity and cytochrome P-450 and b5 content by 73, 54, and 43 percent, respectively. The high doses of gossypol decreased the aniline hydroxylase, cytochrome P-450, and b5 levels by 60, 51, and 46 percent, respectively, as compared to controls. These data indicate that alteration of the hepatic metabolizing system may, in part, be responsible for the secondary toxemic effects seen when gossypol is used to provide antifertility action.