Plaintiffs are entitled to be reimbursed for all of the medical expenses attributable to their injuries. They must first prove that the expenses were due to the defendant’s conduct rather than a preexisting or coincidental condition. They must then prove that the expenses were reasonable and necessary. Finally, they must project the cost of future medical care necessitated by the injury. Each of these issues requires expert testimony, usually available from the plaintiff’s treating physician. (This is true even in medical malpractice cases because it does not require questioning the competence of a fellow physician.) The defendant must then contest the plaintiff’s need for medical care. This is complicated by the general assumption that a plaintiff has no incentive to submit to unnecessary medical care. Unfortunately for the defense, medical expenses have great strategic value.

Unlike medical malpractice litigation, most personal injury cases begin with a plaintiff who was in good health and suffered an acute injury. In an automobile accident case, the plaintiff must prove that the accident was due to the defendant’s negligence. The plaintiff also must put on evidence that the accident caused the injuries in question. This is usually a perfunctory matter because the link between the accident and the plaintiff’s injuries is obvious. The only question is whether some of the medical expenses are attributable to a preexisting condition and would have been incurred without the accident. Even if the plaintiff has chronic back pain, she may still claim that the accident aggravated her problems. The defendant will be liable for the additional expense of treating the now-worsened back pain. Determining the extent that a defendant’s conduct aggravated a plaintiff’s preexisting condition is difficult even in simple automobile accidents. It is frequently the pivotal issue in medical malpractice litigation.