Appeal by the employer and its carrier from a decision and award of the Workmen’s Compensation Board on the ground that there is no substantial evidence to support the board’s finding of a continuing causal relationship. On June 2, 1969 claimant, a mechanic, sustained an injury to his knee when the step of the tractor cab on which he was working collapsed and he fell striking his knee cap against the steel step. The board found that this accidental injury aggravated a pre-existing osteoarthritic condition, and that claimant’s disability subsequent to October 9, 1969 and the recommended surgery were causally related thereto. In our opinion, the record contains sufficient medical testimony to sustain the board’s finding of continuing causally related disability. Decision affirmed, with costs to the Workmen’s Compensation Board. Herlihy, P. J., Staley, Jr., Greenblott, Sweeney and Main, JJ., concur.