Comparison of insertion characteristics of tapered and cylindrical transfixation pins in third metacarpal bones of equine cadavers.

OBJECTIVE To compare heat generation and mechanical bone damage for tapered and cylindrical transfixation pins during drilling, tapping, and pin insertion in equine third metacarpal bones. SAMPLE 16 pairs of cadaveric equine third metacarpal bones. PROCEDURES For cylindrical pin insertion, a 6.2-mm hole was drilled and tapped with a cylindrical tap, and then a standard 6.3-mm pin was inserted. For tapered pin insertion, a 6.0-mm hole was drilled, reamed with a tapered reamer, and tapped with a tapered tap, and then a 6.3-mm tapered pin was inserted. Paired t tests and 1-way ANOVAs were used to compare heat generation (measured by use of thermocouples and thermography), macrodamage (assessed by use of stereomicroscopy), and microdamage (assessed by examination of basic fuchsin-stained histologic specimens) between cylindrical and tapered pins and between tapered pins inserted to various insertion torques. RESULTS Tapered pin insertion generated less heat but resulted in more bone damage than did cylindrical pin insertion when pins were inserted to the same insertion torque. Insertion of tapered pins to increasing insertion torques up to 16 N•m resulted in increased heat generation and bone damage. CONCLUSIONS AND CLINICAL RELEVANCE Tapered pin insertion resulted in lower heat production than did cylindrical pin insertion. However, tapered pin insertion resulted in greater bone damage, which likely was attributable to differences in the tapered and cylindrical taps. A tapered pin may be preferable to a cylindrical pin for insertion in equine cortical bone provided that improvements in tap design can reduce bone damage during insertion.

HSA programs for groups: employer versus employee responsibilities.

Employers implementing a health savings account (HSA) program face a shared compliance burden with their employees. The law dictates that all HSAs are individual accounts that must be opened by an Internal Revenue Service (IRS)-approved custodian or trustee. The individual account features combined with a required third-party custodian place much of the compliance burden for HSAs on the employee and custodian rather than the employer. Employees are compensated for the additional burden because HSAs give them more control over their health care money, and employers are generally pleased with their own reduced compliance burden. The shared compliance responsibilities, however, create confusion and misunderstanding for both employers and employees. This article distinguishes between the responsibilities of the employer and the employees for HSAs.

The impact of health reform on HSAs.

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