The self-insured employer, Hibbing Taconite Mining Company, appeals from the compensation judge’s determination that the employee’s March 30, 1999, work injury was a substantial contributing cause of his right elbow symptoms treated from August 31, 2007, and thereafter. We affirm.

The employee, Kent Drewelow, began working for the employer, the Hibbing Taconite Mining Company, in March 1989. He subsequently worked in a variety of different jobs for this employer.

In February 1990, the employee was seen by Dr. David Johnsrud at the Mesaba Clinic for several non work-related problems, including a right elbow problem. He told the doctor that he suspected a bone spur might be present in his right elbow as a result of having fallen several years earlier while engaged in pheasant hunting. An x-ray revealed a bone spur on the olecranon. The employee was given an elbow pad but apparently received no further treatment for this spur or for his right elbow.

In 1994 the employee sustained an injury to his right arm and elbow while throwing steel at work. He was seen by Dr. Johnsrud and treated with a tennis elbow splint, a steroid injection, and physical therapy, which helped temporarily. A right elbow x-ray taken in December 1994, showed a possible loose body on the olecranon. He was later referred to Dr. Peter Goldschmidt, an orthopaedic surgeon, who saw the employee on August 22, 1995. Dr. Goldschmidt diagnosed right elbow epicondylitis. The employee’s right elbow was treated by corticosteroid injection, but this gave only temporary improvement. The employee underwent right epicondylar release surgery sometime in late 1995 or early January 1996.

When the employee was seen in April 1996 by Dr. Goldschmidt in follow up for his epicondylar release, his right elbow symptoms had fully resolved. However, the employee returned to Dr. Goldschmidt in September 1996 complaining of left elbow discomfort for about four months. The left elbow was noted to be tender over the lateral epicondyle. On October 28, 1996, Dr. Goldschmidt tried injecting the employee’s left elbow. The employee also received physical therapy during October and November 1996.

On March 30, 1999, the employee was sitting on an inverted five-gallon bucket using a two-inch diameter hose to clear spilled material from a concrete floor into a drain, when the control nozzle broke off the hose, causing the water to flow through the hose at full pressure. The employee struggled unsuccessfully to retain control of the hose, and was knocked to the floor. He testified at the hearing below that he fell on both elbows. The hose continued to whip back and forth striking the employee’s lower body several times between the ankles and crotch. The employee was eventually able to escape the flailing hose and close the water valve.

The employee immediately reported the injury to his supervisor. A preliminary investigation report completed by the employer listed bruises to the employee’s wrist, finger, knee and ankle, but did not report any further injury. The employee was taken to the emergency room at the University Hospital in Hibbing, where he was treated for a right knee contusion and soft tissue contusions of his left knee and forearm. No mention was made of any injury to either elbow. He was advised to follow up with his family physician, Dr. Johnsrud. When the employee saw Dr. Johnsrud the next day, March 31, 1999, he again failed to mention any problem with his right elbow. He was treated for leg contusions.

In 2001, the employee sought treatment for his left elbow at the Mesaba Clinic, and was referred to Dr. Goldschmidt, with whom he had previously treated in 1994. The employee told Dr. Goldschmidt that he had injured his left elbow in 1999 at work when he was handling a large hose and was thrown to the ground, after which he had continued to note waxing and waning symptoms in the left elbow, including pain over the tip of the olecranon. Dr. Goldschmidt diagnosed possible loose fragments in the olecranon bursa after the employee’s fall. An x-ray study of the employee’s left elbow on February 20, 2001, showed an olecranon spur.

The employer initially denied liability for the left elbow condition. The employee then wrote a letter to the employer on April 25, 2002, in which he stated that, during the 1999 incident with the hose, he “had a hard fall on both my elbows to the floor.” The self-insured employer subsequently accepted liability for the left elbow problem.

By some time in 2006, the employee started to have pain in the right elbow. He testified that the pain gradually continued to worsen but that he had delayed seeking treatment because it did not initially affect his ability to work. He returned to Dr. Goldschmidt on August 31, 2007, for treatment for the right elbow. Dr. Goldschmidt recommended an excision of the olecranon spur in the employee’s right elbow.

In December 2007, the employee underwent the suggested surgery. The pre-operative and post-operative diagnoses on the surgical report both read “symptomatic olecranon spur right elbow.” Procedure details in the surgical report noted that “there was a bony spur which was mobile in the soft tissue which was carefully dissected free measuring about 1 cm x 0.5 cm.” In a chart note dated December 21, 2007, Dr. Goldschmidt noted that “[a]t the time of surgery, he was found to have a loose body which likely was related to his previous fall.” In a letter dated January 30, 2008, Dr. Goldschmidt further elaborated on his opinion, stating, “I believe that the bone chip removed [from the employee’s elbow] was a result of the fall and this represented a small piece of bone which had broken away from the elbow bone.”

On December 17, 2007, the employee filed a medical request seeking payment of the bills and expenses related to his right elbow treatment in 2007, alleging that the treatment was related to the 1999 work injury. The employer denied liability on the basis that the disputed treatment was not related to the work injury. The matter was referred to the Office of Administrative Hearings. The employee then retained counsel and filed a request for formal hearing. Following the hearing, a compensation judge found that the 1999 work injury was a substantial contributing cause of the employee’s right elbow symptoms as treated from August 31, 2007. The self-insured employer appeals.

The compensation judge found that the employee’s March 30, 1999 work injury was a substantial contributing cause of his right elbow symptoms treated from August 31, 2007. This finding was supported by the employee’s testimony describing his injury, and by the expert medical opinion of Dr. Goldschmidt.

The self-insured employer argues that the compensation judge’s finding should be reversed in light of the following: 1) there was no mention of a right elbow injury at the time of the initial report or treatment for the 1999 work injury and the employee did not claim that the work injury resulted in right elbow problems until more than eight years after the work injury; 2) the surgery performed for the employee’s right elbow consisted of an excision of a right olecranon spur, and the medical records clearly show that such a spur was present in the employee’s right elbow as early as 1990, nine years prior to the occurrence of the work injury. The employer argues that in light of these undisputed facts, the evidence overwhelmingly supports a determination contrary to that reached by the compensation judge.

The compensation judge accepted the employee’s testimony that he fell on both elbows onto a concrete floor at the time of the 1999 work injury. The probable validity of this testimony with respect to the right elbow here at issue was bolstered by the fact that the employee described striking both elbows in this manner in 2002, long before the emergence of any right elbow symptoms or any claim for compensation related to the right elbow. The employee also testified that he did not initially have reason to believe that he had sustained injury to his elbows, as they did not become symptomatic until much later, so that there was no reason for him to have reported elbow injuries at the time of his initial treatment immediately after the 1999 injury. Credibility determinations are for the compensation judge. Even v. Kraft, Inc., 445 N.W.2d 831, 42 W.C.D. 220 (Minn. 1989).

As to the significance of the pre-existing bone spur on the employee’s right elbow, it is a basic tenet of workers’ compensation law that the work injury need not be the sole cause of disability. When a work injury substantially aggravates, accelerates, or combines with a pre-existing disease or latent condition to produce a disability, the condition is deemed compensable. See, e.g., Vanda v. Minnesota Mining & Mfg. Co., 218 N.W.2d 458, 27 W.C.D. 379 (Minn. 1974); Palmer v. Pro Floor, Inc., slip op. (W.C.C.A. January 25, 2006).

In that context, it appears to us that the result in this case ultimately hinges on the interpretation given to the wording of the causation opinion of Dr. Goldschmidt as expressed in his chart note of December 21, 2007, and his letter dated January 30, 2008. The doctor’s explanation in these records is unclear and is susceptible to two different interpretations. There is no question that the bone spur for which the surgery was performed predated the work injury. However, under one reasonable interpretation of the doctor’s explanation, he seems to have considered that the bone spur, presumably stable prior to the 1999 work injury, had been sufficiently loosened by the impact of the employee’s elbows striking a concrete floor during the 1999 work injury and that the work injury on that date was the precipitating cause of the piece of bone eventually breaking away from the elbow bone some years later, causing the onset of the employee’s right elbow symptoms in 2006 as treated in 2007. This interpretation has further support in the fact that the pre-existing bone spur on the employee’s right elbow was not disabling prior to the work injury.

The employer and insurer did not depose Dr. Goldschmidt to inquire as to the basis for his opinion on causation, nor did they offer any expert medical opinion to counter his opinion on causation. Where the expert evidence on the issue of causation was so limited, we cannot say that the compensation judge clearly erred in accepting Dr. Goldschmidt’s opinion, since, although that opinion was susceptible to more than one interpretation as to the basis for the opinion, the interpretation adopted was reasonable. We therefore affirm.