[¶ 1.] In this appeal, we hold that a workers’ compensation claimant failed to *262 establish that his employment was a major contributing cause of his knee condition.
FACTS
[¶ 2.] George L. Grauel worked as a custodian for the South Dakota School of Mines & Technology (SDSM & T). He injured his left knee at work on August 8, 1996. Grauel testified that he felt his knee “pop” and experienced immediate pain as he walked to his next duty station after he finished sweeping a floor. He notified his supervisors of the incident and visited a doctor that day.
[¶ 8.] The initial doctor referred Grauel to Dr. Hollis L. Ahrlin, Jr., an orthopedic surgeon, for examination. Dr. Ahrlin examined him and found “some” swelling of the left knee. Although Grauel complained of tenderness and discomfort, Dr. Ahrlin noted that he had almost full range of motion, stable ligaments and the x-rays of his left knee showed no problems. Dr. Ahrlin stated in his deposition that he suspected a torn cartilage or other internal knee problem at the time. He prescribed leg exercises and took Grauel off work.
[¶ 4.] Grauel treated with Dr. Ahrlin several times over the following months and did not return to work during this time. Ultimately, Dr. Ahrlin decided Grauel needed arthroscopic surgery. On October 24, 1996, Dr. Ahrlin performed an arthroscopic general joint debridement consisting of removal of loose bodies within the knee, trimming of the medial femoral con-dyle and releasing a couple of synovial plica. During the surgery, Dr. Ahrlin noted degenerative changes under the kneecap and the medial femoral condyle.
[¶ 5.] On November 19, 1996, Grauel returned to his custodial duties for the first time since the August 8th incident. He continued working until early April 1997 and resigned on April 15, 1997. Grauel testified that he resigned because his custodial duties increased the risk of aggravating his knee injury and caused his knee discomfort.
[¶ 6.] Grauel requested workers’ compensation benefits from SDSM & T for the August 8th knee injury. SDSM & T denied his claim. On February 18, 1999, the Department of Labor held a hearing at which Grauel presented Dr. Ahrlin’s deposition testimony. SDSM & T presented deposition testimony of Dr. Wayne Anderson who had performed an independent medical evaluation on behalf of SDSM & T. The administrative law judge awarded benefits concluding that Grauel’s injury arose out of and in the course of his employment and that Grauel’s employment was a major contributing cause of injury to his knee. SDSM & T appealed to the circuit court, which reversed the Department of Labor’s award of benefits. Grauel appeals. We affirm.
[¶ 7.] Our standard of review in workers’ compensation cases is well settled. We make the same review of the agency’s decision as the circuit court, and the circuit court’s decision enjoys no presumption of correctness.
Appeal of Templeton,
DECISION
[¶ 8.] South Dakota Workers’ Compensation Law defines what constitutes a com-
*263
pensable injury. SDCL 62-1-1(7). The legislature defined “injury” or “personal injury” in the context of workers’ compensation law as only those injuries arising
out of
and
in the course
the worker’s employment and not including any diseases except a disease caused by the injury.
Id.; Steinberg v. South Dakota Dep’t of Military & Veterans Affairs,
[¶ 9.] As we noted in
Steinberg,
the legislature’s use of
condition
rather than
injury
in the amendment is significant.
Steinberg,
[¶ 10.] 1. Grauel established that his injury arose out of his employment.
[¶ 11.] Grauel had the burden to prove by a preponderance of the evidence “all facts essential to compensation.”
Westergren v. Baptist Hosp.,
[¶ 12.] This Court recently rejected the increased risk doctrine as a method of showing an injury arose out of employment.
Steinberg,
[¶ 13.] The parties agree Grauel was injured in the course of his employment. Much of the parties’ dispute focused on whether Grauel was “twisting” or turning when his knee popped or whether he was simply “walking.” We believe the dispute is of no consequence. The question is, did the employment contribute to causing the injury or is the activity one in which the employee might reasonably be expected to engage or did the employment activity bring about the disability on which the compensation is based?
[¶ 14.] Grauel testified, without contradiction, that he was working his regular shift and his knee popped while he was walking to his next duty. Fulfillment of Grauel’s custodial duties necessarily involved walking, twisting and turning. Additionally, SDSM & T’s independent medical examiner, Dr. Anderson, testified that any walking or moving contributes to “what happens orthopedieally.” An injury occurring during any of these employment activities would be an activity which contributed to Grauel’s knee injury
or
in which he would reasonably be expected to engage
or
which brought about the disability upon which his compensation was based. Accordingly, Grauel’s knee injury arose out of his employment. This conclusion is consistent with workers’ compensation purpose of replacing common law’s doubtful tort based recovery system with a system based on a right to relief iipon establishing the fact of employment,
“automatic and certain, expeditious and independent of proof of fault.” Steinberg,
[¶ 15.] 2. Grauel failed to establish that his employment or employment related activity was a major contributing cause of his condition or his disability, impairment or need for treatment.
[¶ 16.] As discussed earlier, the South Dakota Legislature amended SDCL 62-1-1(7) adding the “major contributing cause” language in 1995.
Steinberg,
(7) “Injury” or “personal injury,” only injury arising out of and in the course of the employment, and does not include a disease in any form except as it results from the injury. An injury is compensa-ble only if it is established by medical evidence, subject to the following conditions:
(a) No injury is compensable unless the employment or employment related activities are a major contributing cause of the condition complained of; or
(b) If the injury combines with a preexisting disease or condition to cause or prolong disability, impairment, or need for treatment, the condition complained of is compensable if the employment or employment related injury is and remains a major contributing cause of the disability, impairment, or need for treatment.
(c) If the injury combines with a preexisting work related compensable injury, disability, or impairment, the subsequent injury is compensable if the subsequent employment or subsequent em *265 •ployment related activities contributed independently to the disability, impairment, or need for treatment.
SDCL 62-1-1(7) (emphasis added).
[¶ 17.] In
Steinberg,
we corrected the circuit court’s misinterpretation of the 1995 amendment. The circuit court in
Steinberg
interpreted the additional language to mean the legislature had raised the standard by which an employee must show a causal connection.
Steinberg,
[¶ 18.] To determine if Grauel established by a preponderance of medical evidence that his employment was a major contributing cause of his knee condition or his disability, impairment, or need for treatment, we examine the medical testimony. In this case, that consists solely of the deposition testimony of Dr. Ahrlin and Dr. Anderson, which we review de novo.
[¶ 19.] Dr. Ahrlin first saw Grauel on August 9, 1996, one day after the injury, and remained his treating physician throughout the course of the injury and his resulting knee condition. During his deposition, Dr. Ahrlin continually stated that Grauel’s work-related incident was not just the major contributing cause of Grauel’s knee problem but was the “only” contributing factor to the knee problem. The difficulty with Dr. Ahrlin’s statement is its basis. In reviewing Dr. Ahrlin’s deposition, it is clear he assumed that any injury occurring at work is work-related: “I guess whatever his injury or whatever his activity was, whether it was a major or minor, if — if he was at work and he developed a problem, I guess that it would have to be considered a work-related problem.” This assumption is incorrect. The mere occurrence of an injury at work does not mean it is ipso facto work-related. As discussed above, the employee must establish by a preponderance of the evidence that his injury arose out of and in the course of his employment and that his employment was a major contributing cause of his condition or his disability, impairment, or need for treatment. Showing the injury occurred at work is just one piece of evidence an employee can utilize in proving his case, but he must prove more than that fact alone to show the required causal connection and that his employment was a major contributing cause of his condition or his disability, impairment, or need for treatment.
[¶ 20.] Additionally, Dr. Ahrlin’s testimony is inconclusive. First, he firmly stated his opinion that Grauel’s employment activities were a major contributing cause of Grauel’s knee condition only to later abandon that opinion by giving no opinion as to whether Grauel’s knee problems developed over time or instantaneously the day of the work injury. In order to express his opinion as to major contributing cause, logic would expect Dr. Ahrlin to have an opinion as to whether the injury developed over time or occurred instantaneously the day of the work injury. Dr. Ahrlin’s failure to state an opinion on this topic places his ultimate opinion concerning major contributing cause in question. Combining this information with the earlier discussion of Dr. Ahrlin’s faulty assumption about work-related injuries leads this Court to find Dr. Ahrlin’s testimony as to major contributing cause is inconclusive and therefore incapable of sustaining Grauel’s burden of proof on that issue in this case.
[¶ 21.] Although unnecessary given our discussion of Dr. Ahrlin’s deposition, we briefly discuss Dr. Anderson’s deposition. He performed an independent medical evaluation of Grauel on behalf of SDSM & T on June 8, 1998, almost two years after the injury. He concluded that Grauel’s employment was not a major contributing cause of his knee condition. Dr. Anderson opined that Grauel suffered from degenerative arthritis of the knee and that this *266 was the major contributing cause of his knee condition. Dr. Anderson reasoned that the presence of loose bodies in the knee combined with minor swelling and full range of motion at the time of the accident indicated that the preexisting condition of degenerative arthritis rather than employment activities was the major contributing cause of Grauel’s knee condition. Although this contradicts the treating physician, Dr. Ahrlin, Dr. Anderson’s opinion is logical and supported in the record.
[¶ 22.] The Department of Labor and Grauel’s counsel stress the fact that Dr. Anderson did not review all of Grauel’s medical records. However, as this Court views the record, this point carries little weight. First, Dr. Anderson was missing only two records' — a visit to Dr. Ahrlin on October 21, 1996 and an impairment rating visit to Dr. Ahrlin on May 29, 1998. Second, SDSM & T’s counsel presented Dr. Anderson with each of these records during his deposition, and he stated that the information contained in those two records did not change his opinion.
[¶-23.] Grauel’s counsel contends that Dr. Ahrlin’s testimony should be accepted as satisfying Grauel’s burden of proof, but as discussed above, we disagree. Dr. Ahr-lin’s testimony is inconclusive and simply does not sustain Grauel’s burden to prove by a preponderance of the evidence that his employment was a major contributing cause of his knee condition. Additionally, when reviewing the two depositions together, Dr. Anderson’s testimony is based on logical reasoning supported by evidence in the record. Although we did find Grau-el’s injury arose out of his employment, he needed to also establish that his employment was a major contributing cause of his knee condition. This he failed to do.
[¶ 24.] Affirmed.