## Facts

- Johnny Jones suffered a left-leg injury in an automobile accident and was treated surgically at Roseland Community Hospital.
- During hospitalization, he developed pseudomonas osteomyelitis in the fractured leg.
- Jones and his wife sued multiple physicians (orthopedic, general, and plastic surgery specialists) and alleged negligent diagnosis and treatment led to amputation of the left leg.
- Plaintiffs identified Dr. Malcolm Deam, a physician board-certified in internal medicine and infectious diseases, as their standard-of-care expert.
- Defendants moved in limine to bar Dr. Deam from testifying on the surgeons’ standard of care because he was not a surgical specialist.
- After a qualification hearing, the trial court excluded Dr. Deam’s standard-of-care testimony based on a same-specialty approach and certified a question for interlocutory review.

## Issues

1. In a medical malpractice action against surgical specialists, must a plaintiff’s expert practice in the same specialty to testify on the applicable standard of care, or may a physician from another specialty testify if sufficiently familiar with that standard?

## Decision

- The Illinois Supreme Court held that an expert witness need not practice in the same specialty as the defendant to testify on the standard of care.
- The trial court erred by excluding Dr. Deam solely because he was not a surgeon, applying an overly restrictive legal standard.
- The case was remanded for reconsideration of Dr. Deam’s qualifications under the correct, knowledge-based test.

## Legal Principles

- Expert qualification in medical malpractice turns on the witness’s knowledge of, and familiarity with, the applicable standard of care, not formal identity of specialty.
- A physician may testify on another field’s standard of care if the physician is licensed and demonstrates familiarity with the methods, procedures, and treatments ordinarily used in that field and sufficient knowledge of the relevant standard.
- Trial courts have broad discretion over expert admissibility, but that discretion must be exercised using the proper legal standard and a foundation-focused inquiry rather than a categorical same-specialty rule.

## Conclusion

The court rejected a rigid same-specialty requirement for standard-of-care experts and required a functional inquiry into whether the proposed expert has demonstrated sufficient familiarity with the defendant’s field and the relevant treatment to give reliable standard-of-care testimony.


Jones v. O'Young, 607 N.E.2d 224 (Ill. 1992)