The employee appeals from the judge’s decision that the employee did not sustain a consequential injury to his right knee.  We affirm.

The employee sustained a work-related injury to his left knee on April 4, 1986, while employed by Marlow Floor Covering [the employer].  The employer and its insurer admitted liability.  In about 1998, Dr. Jack Bert became the employee’s treating doctor for this injury.

The employee had ongoing left knee symptoms after that injury and underwent numerous related surgical procedures, including arthroscopic knee surgeries and a total knee replacement.  Following the knee replacement, performed on February 13, 2007, the employee continued to have limited range of motion, and Dr. Bert performed left knee manipulations on May 15, 2007, and August 7, 2007.

The first notation in any medical record regarding the employee’s right knee was the May 15, 2007, operative report by Dr. Bert.  That report documented the left knee manipulation performed at that time but also reflected, “[w]ith respect to the right knee, 15 cc of fluid were aspirated and the right knee was injected with 3 cc of Celestone and 1 cc of Marcaine.”  A form completed by the employee at the time of a July 24, 2007, visit to Dr. Bert indicated that the employee had been experiencing a new problem - - sharp right knee pain.  This complaint was not discussed in Dr. Bert’s treatment note of that date but is noted in his treatment note of September 5, 2007, and Dr. Bert ordered an MRI of the employee’s right knee at that time.

The employee recalled having first experienced right knee pain in October of 2007, while trying to walk with a crutch or a cane.  He sustained no specific right knee injury.

The employee has been diagnosed with a degenerative condition in his right knee, including patellofemoral arthrosis, and medical compartment arthrosis with a degenerative medial meniscus tear and patellofemoral chondromalacia.  Treatment has included Synvisc injections and arthroscopic right knee surgery.

On January 11, 2008, Dr. Bert opined that the employee’s original left knee injury had resulted in ongoing complaints of right knee pain and degenerative changes.

Dr. Loren Vorlicky performed an independent medical examination for the employer and insurer on February 25, 2008.  According to his report, the employee related that he had developed right knee swelling over the course of using crutches to treat his left knee.  The employee also stated that he had favored his left knee for many years and had therefore overused his right knee.  It was Dr. Vorlicky’s opinion that the employee’s right knee condition had no relationship to the 1986 injury and that there was no evidence that the employee had developed a right knee injury due to his work-related left knee condition.

In June of 2008, Dr. Bert was asked to clarify his opinion in light of Dr. Vorlicky’s report.  In a letter dated June 27, 2008, Dr. Bert stated that the employee’s right knee condition was causally related to the employee’s original left knee injury due to the fact that the employee had been walking with an abnormal gait.

An amended claim petition was filed on September 3, 2009, seeking temporary total disability benefits, medical expenses, and rehabilitation services as a result of an alleged consequential right knee injury.  The employer and insurer denied liability for the employee’s right knee condition.

On March 2, 2010, Dr. Vorlicky performed a repeat independent medical examination.  In his report of March 31, 2010, Dr. Vorlicky stated, “I do not believe that his gait pattern difficulties would result in significant alteration in the weight bearing status of his right knee and thereby the kinematics of his right knee.”  He went on to state that no literature would support the conclusion that the employee’s right knee condition was consequent to the left.  In Dr. Vorlicky’s opinion, osteoarthritis is idiopathic and would likely have developed independent of the work injury.

Dr. Bert subsequently responded to Dr. Vorlicky’s March 31, 2010, report.  He agreed that there were no studies to support the concept of degenerative arthritis developing in a right knee resulting from surgery on the left, “because it would be impossible to prove in a randomized fashion.  This is due to the fact, as noted by Dr. Vorlicky, that degenerative arthritis can develop ideopathically.”  According to Dr. Bert, patients that have surgery on one knee develop contralateral knee pain “as a result of unweighing the operative knee and putting the majority of weight on the contralateral knee thus resulting in degenerative changes in the non-operative knee.”

The matter proceeded to hearing, and, in findings and order filed on October 15, 2010, the compensation judge denied the employee’s claim for benefits related to his right knee condition on causation grounds.  The employee appeals.

The compensation judge made the following finding:

In his memorandum, the judge indicated that he was not persuaded by the opinion of Dr. Bert, stating:

The employee contends that the compensation judge erred in requiring the employee’s treating doctor to quantify the amount of time that the employee stood or walked with an altered gait, requiring him to quantify the amount of time that the employee spent with all of his weight on his right leg, requiring him to identify medical studies supporting the treating doctor’s opinion, and requiring him to rule out other possible causes for the employee’s right knee condition.  We conclude, however, that the compensation judge did not reject Dr. Bert’s opinion on foundation grounds, which, we agree, would have been improper.  Rather, the comments in the judge’s memorandum merely explain why he found Dr. Bert’s opinion unpersuasive.

The judge’s denial of the employee’s claim was based on his conclusion that the employee failed to meet his burden of proving that his admitted left knee injury was a substantial contributing cause of the degenerative condition in his right knee.  In that regard, the judge noted in his memorandum:

The employee argued in his brief on appeal, and at oral argument, that he met his burden of proof by providing the opinions of Dr. Bert.  However, the question before this court is not whether the evidence might have supported a contrary finding, but whether the finding actually made by the compensation judge was adequately supported by the record.  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Furthermore. a causation opinion rendered by a treating doctor “may be legally sufficient to initiate a claim but it may not have the persuasiveness necessary to establish a claim in a contested hearing.”  Wienan v. Carlton Co., No. WC07-252 (W.C.C.A. May 5, 2008).  The burden of proof is generally on the employee, and a claim must be proven by a preponderance of the evidence.  Minn. Stat. §176.021, subd. 1.  “Where two opposing inferences can be drawn with equal justification from the same circumstantial evidence, it cannot be said that one preponderates over the other, and in that event the party having the burden of proof must lose.”  Dille v. Knox Lumber/Div. of SW. Forest, 452 N.W.2d 679, 681, 42 W.C.D. 819, 823 (Minn. 1990).

In this case, where Dr. Bert offered the opinion that altered gait related to the employee’s knee injury led to degeneration in the opposite knee, but Dr. Vorlicky provided an equally plausible opinion that the degeneration in the employee’s opposite knee was ideopathic, substantial evidence supports the judge’s finding that the employee did not meet his burden of proof.  See also Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  We therefore affirm the judge’s findings in their entirety.