The recommended safe dosage of erythromycin for a child is 20 mg/kg/day in four equal doses. The child weighs 33 lb. The medication is supplied in 125 mg/mL. What is the safe and therapeutic dosage for this child?

Choice A reason: Stress fractures result from repetitive microtrauma, common in athletes, not typically associated with abuse. In children, they occur from overuse (e.g., sports), not acute trauma, making them less suspicious for non-accidental injury compared to other fracture types.
Choice B reason: Compound fractures, where bone pierces the skin, result from high-impact trauma (e.g., falls). While possible in abuse, they are less specific, as they occur in accidents, making them less indicative of non-accidental injury than spiral fractures.
Choice C reason: Spiral fractures occur from twisting forces, often seen in abuse when a limb is forcefully twisted (e.g., by an adult). In children, whose bones are flexible, spiral fractures suggest significant force, raising suspicion of non-accidental trauma.
Choice D reason: Greenstick fractures, where the bone bends and partially breaks, are common in children due to pliable bones. They occur in accidents or minor trauma, making them less specific to abuse compared to spiral fractures’ association with twisting mechanisms.

Choice A reason: Washing the fixator frame may maintain hygiene but does not directly address the primary infection risk at pin sites, where skin breaks allow bacterial entry. Pin sites are more critical, as infections like osteomyelitis can develop from poor pin care.
Choice B reason: Releasing fixator tension disrupts the device’s stability, risking bone misalignment and delayed healing. It does not reduce infection risk and may increase tissue trauma, potentially creating more entry points for bacteria at the pin sites.
Choice C reason: Avoiding movement by holding the fixator prevents normal joint mobility, risking stiffness, but does not address infection risk. Pin sites remain the primary infection source, as bacteria can enter through skin breaks, requiring specific cleaning protocols.
Choice D reason: Regular pin care (every shift) with sterile technique (e.g., chlorhexidine) removes debris and bacteria from pin sites, reducing the risk of osteomyelitis. External fixators penetrate skin, creating infection-prone areas, making frequent, meticulous pin care the most effective intervention to prevent infection.