The issue in this workers’ compensation case is whether claimant’s right knee condition is compensable and, if it is, which of two carriers is responsible.
Claimant is a 60-year old heavy equipment operator. An operation to remove cartilage from the inside of his right knee was performed in 1947; a second operation for the same purpose was performed on the left knee in 1967. In May, 1978, while climbing down from the road grader he normally operated. for his employer, claimant slipped and injured his left knee. SAIF accepted responsibility for the injury and paid time loss benefits. Claimant testified that his right knee began to cause him pain within a day or two after the injury to the left knee, although his treating physician did not document any symptoms in the right knee until August, 1978. On July 1, 1978, Multnomah County became a direct responsibility employer. On January 17, 1979, SAIF denied responsibility for the right knee condition; the county denied responsibility on January 23,1979.
The referee, relying on testimony by claimant’s treating physician, an orthopedic surgeon, found “a direct causal connection” between the injury to the left knee and claimant’s right knee problems. The treating physician, Dr. Eilers, had stated that two work-related factors caused the onset of symptoms in claimant’s right knee. First, he said, the pain from the injury to the left knee caused claimant to shift more weight to the right knee, which was already weakened by degenerative arthritis; second, claimant’s ordinary position in the operation of the road grader, leaning on the right leg to look out and observe the blade, placed stress on the right knee. Dr. Pasquesi, a consulting physician, agreed. He described claimant as a man with a preexisting degenerative arthritic condition in the right knee, which was “undoubtedly aggravated” by the May, 1978, injury.
The Workers’ Compensation Board, citing Weller v. Union Carbide Corporation, 288 Or 27, 602 P2d 259 (1979), reversed the referee, finding that claimant had not shown that his “underlying condition was worsened by his work activity.”
*470In view of the evidence we have cited, the Board’s resort to Weller is obscure. The Weller test is the standard of proof relating to a claim for an occupational disease. In the case before us, however, claimant has not filed an occupational disease claim. SAIF and the employer were advised of claimant’s problem with his right knee through the medical reports they received from claimant’s treating physician relating to the May, 1978, injury to claimant’s left knee and an injury to his left elbow suffered in another fall from his grader in September, 1978; no new claim was filed. Claimant’s attorney, at the hearing before the referee, said the treating doctor had never told claimant he had an occupational disease, and claimant testified he had never heard the words “occupational disease” before the day of the hearing. Following the hearing before the referee, claimant’s attorney wrote to the referee, stating that claimant was, by that letter, making an occupational disease claim. Both carriers were allowed to respond. Before us, claimant maintains that he should prevail either on his claim that the right knee condition is “a part of the accepted industrial injury to the left knee” or on a claim for an occupational disease.
As we view this case, the Board’s application of an occupational disease/ Weller analysis was misplaced. It was the injury to his other knee which materially contributed to the symptomatology which is before us now; the testimony of claimant’s treating physician clearly establishes that fact. Claimant is entitled to receive medical services for the right knee. See Smith u. Brooks-Scanlon, 54 Or App 730, 636 P2d 433 (1981); Wood v. SAIF, 30 Or App 1103, 1108, 569 P2d 648 (1977), rev den 282 Or 189 (1978).
In view of our conclusion that the right knee condition is to be treated as arising out of the compensable injury to the left knee, SAIF is the responsible carrier. See Eber v. Royal Globe, 54 Or App 940, 636 P2d 1007 (1981).
The order of the Board is reversed and remanded with instructions to reinstate the referee’s opinion.