On April 25, 2012, the United States District Court for the Eastern District of Pennsylvania issued an opinion in Mertzig v. Booth, et al., ruling that patient plaintiff would not be allowed to present expert testimony to bolster a medical malpractice claim under res ipsa loquitur, given that she had previously certified that such testimony was unnecessary to prove her claim.

In the underlying case, plaintiff underwent a knee replacement surgery performed by defendant physician on May 29, 2007. Following surgery, the prosthetic components began to loosen, and she was informed that the prosthetic knee had actually been infected when it was initially placed into her body.

After filing suit against defendant, plaintiff filed certificates of merit under Pa.R.C.P. 1042.3(a)(3), certifying that expert testimony was not required to prove her claims against defendant. However, plaintiff subsequently produced expert reports in support of a theory of res ipsa loquitur. In response, defendant filed motions for summary judgment, contending that such testimony was barred pursuant to plaintiff’s previous certification under Rule 1042.3(a). Acknowledging that expert testimony was required to pursue her claims, plaintiff then argued that such certifications did not apply, given that res ipsa loquitur had been invoked.

On review, the court noted that according to the Note to Rule 1042.3(a), certifications that expert testimony is not required may not be revoked, except in the case of “exceptional circumstances.” Observing that plaintiff had failed to cite any case law stating that expert testimony may be used to establish res ipsa loquitur after such a certification had been filed, the court deferred to the guidance of the Note, and concluded that the discovery that expert testimony was required to support plaintiff’s claims did not qualify as “exceptional circumstance.”

Holding that plaintiff would be bound to her certification under Rule 1042.3(a)(3), the court further explained that under the elements of res ipsa loquitur, expert testimony must be presented in medically complex cases, in order to effectively eliminate alternate causal factors, such as, for example, the conduct of third persons. Notably, the expert reports submitted by plaintiff confirmed that the issues of causation were complex and not within the comprehension of laypersons. However, because plaintiff had certified that expert testimony was unnecessary, she was precluded under Rule 1042.3(a)(3) from relying on such testimony.

After analysis of the expert reports, the court concluded that the opinions therein failed to sufficiently eliminate other causes of plaintiff’s injury. Therefore, because plaintiff was ultimately unable to prove her case without or without the expert testimony at issue, the court granted the defendant’s motion for summary judgment.