Reversed and Remanded.

Unpublished opinion is below.

WILLIAM BLAKE, Claimant Below, Appellant, v. STATE OF DELAWARE, Employer Below, Appellee. No. 477, 2001 In the Supreme Court of the State of Delaware. Submitted: January 8, 2002 Decided: March 12, 2002

Before VEASEY, Chief Justice, WALSH and STEELE, Justices.

MYRON T. STEELE, Justice.

ORDER

This 12th day of March 2002, upon consideration of the briefs of the parties, it appears to the Court that:

(1) After conducting a hearing on Appellant, Claimant-below, William H. Blake's Petition to Determine Additional Compensation Due, the Industrial Accident Board granted Blake's petition and awarded him medical benefits associated with surgery performed in July 2000, total disability benefits during the post-operative recovery period, and certain fees relating to the prosecution of his claim. On appeal by Appellee, Employer-below, the State of Delaware, the Superior Court reversed the Board's determination. This is Blake's appeal of the Superior Court's decision.

(2) In April 1997, Appellant Blake injured his right knee while responding to a fire in an apartment complex in his capacity as a volunteer firefighter with the Christiana Fire Company. Blake's family physician referred him to Dr. William Newcomb, a board-certified orthopedic surgeon, for treatment of the knee injury. Dr. Newcomb had performed arthroscopic surgery on Blake's right knee in 1984 and had examined that knee again in 1991. As part of his 1991 examination, Dr. Newcomb ordered a set of X-rays that revealed no significant wear of Blake's joint space. When Dr. Newcomb examined Blake after the 1997 accident, X-rays revealed a narrowing of the lateral compartment of the right knee.

In August 1997, Dr. Newcomb performed an arthroscopy that confirmed what he termed a "moderately severe" degenerative condition. Over the next two years, periodic examinations showing continuing deterioration led Dr. Newcomb to conclude that an osteotomy was necessary to treat Blake's right knee. Dr. Newcomb performed the procedure in July 2000. In August 2000, Blake filed his petition with the Board.

(3) On appeal, the Superior Court judge correctly noted that the appropriate standard for determining causation in a worker's compensation claim is the same "but for" standard as would be applied in tort. In applying this rule, she held that the evidence presented through the deposition testimony of Dr. Newcomb did not support the requisite finding of causation necessary to prove Blake's claim. That analysis is based on Dr. Newcomb's statement that he was satisfied to a reasonable medical certainty that the 1997 accident was merely a "substantial cause" of the acceleration of Blake's condition, not the "but for" cause. However, Dr. Newcomb went on to state unequivocally that he was satisfied to a reasonable medical certainty that the accident in question accelerated the condition that required Blake to undergo an osteotomy. We find this second statement to be sufficient evidence for the Board to infer that the accident proximately caused the surgery and that the Superior Court judge erred by ruling to the contrary.

(4) The Superior Court judge further erred when she stated that the appropriate legal standard for causation was whether the surgery would ever have been required but for the accident. The proper standard, correctly applied by the Board, is whether the surgery would have been required at that time but for the accident. Therefore, Dr. Newcomb's concession during his deposition that Blake would have eventually required the same surgery regardless of the accident does not preclude recovery. Moreover, the duty to evaluate the credibility of a witness and weigh the evidence lies solely with the Board. Where that evidence is adequate to support the Board's conclusions, its decision should not be disturbed absent an error of law. By concluding that the surgery might have been necessary at the time it was performed, even if the accident had never taken place, the Superior Court judge chose to believe the testimony of the State's medical expert over that of Dr. Newcomb, thus improperly substituting her evaluation of the evidence for that of the Board. The fact that neither side's expert could precisely pinpoint the future date when it would have been necessary is irrelevant to this analysis.

(5) Finally, the Superior Court judge erred by concluding that the Board lacked "substantial competent evidence" to infer causation because Dr. Newcomb's opinion lacked a substantial factual basis. Dr. Newcomb testified that he based his opinion that a rapid change in the degeneration of the lateral joint space occurred as a result of the 1997 accident on his comparison of X-rays taken in 1991 and 1997 with the deterioration he found as a result of his examinations following the accident. An expert medical opinion based on the interpretation of appropriate objective test results does not lack a substantial factual basis. Because Dr. Newcomb's opinion had a substantial basis in fact, we find that the Superior Court judge again improperly substituted her analysis of the evidence for that of the Board when she held that Dr. Newcomb's testimony was conclusory.

NOW, THEREFORE, IT IS ORDERED that the Superior Court's judgment is REVERSED and this matter REMANDED to the Superior Court with direction to affirm the award of the Industrial Accident Board.