The employer and insurer appeal from the compensation judge's conclusion that the employee’s left knee injury arose out of and in the course of her employment.  We affirm.

In August of 2005, Delores Midas was employed part time in the floral department of Coborn’s, Inc./Cash Wise Foods, for whom she had worked for twenty-six years.  On August 18, 2005, Ms. Midas [the employee] sustained an injury to her left knee when she fell during working hours on the premises of Coborn’s, Inc./Cash Wise Foods [the employer], landing knee-first on the hard floor.  The injury occurred in the check-out area of the employer, evidently about seventy feet from the floral department, as the employee was in the process of retrieving a shopping cart from that area in which to haul empty boxes from the floral department to the employer’s crusher, one of her normal floral department duties.  The employee immediately reported the injury to her supervisor, Jane Oleen, who instructed the employee to report it to the employer’s human resources manager, Jean Honer.  Ms. Honer completed an internal “First Report of Injury” on that date, on which she reported that the injury occurred when the employee “tripped or shoe stuck to floor & she fell forward on her knees & hands.”^[1]  On the date of her injury, the employee was seventy-two years old and was earning a weekly wage of $285.71.

The employee was sent by the employer for treatment on that same date to Midwest Occupational Medicine, where she saw Physician’s Assistant Margaret Lindberg.  PA Linderg’s history reports that, at about 1:00 that afternoon, the employee “felt like her shoe stuck to the floor and she fell forward landing on her left knee” and that it was now “very painful to try to walk on [the knee] at all.”  PA Lindberg diagnosed a patella fracture, fitted the employee with a knee immobilizer, prescribed medication, restricted the employee from working, referred her to an orthopedist, and released her in a wheel chair.  On August 19, 2005, the day after her injury, the employee saw orthopedist Dr. Chad Holien, whose treatment record on that date reports that the employee “states that on August 18, 2005, she slipped and fell on the stairs and landed on her left knee,” thereafter experiencing immediate pain.  Upon review of x-rays, Dr. Holien diagnosed a “[l]eft anterior pole patellar fracture” and anticipated the necessity of fixation of the fracture if the employee continued to have difficulty with straight leg raising or if there was any displacement of the fracture.  On a follow-up examination on August 23, 2005, x-rays did reveal displacement of the fracture, and Dr. Holien recommended surgery at the employee’s earliest convenience.

On August 24, 2005, the employer completed two additional First Report of Injury forms, one of which reports that the employee “was walking, tripped or foot stuck to floor, fell forward and landed on left knee and hands.  Fractured left knee cap” and the other of which reports that the injury occurred when the employee “tripped or foot stuck to floor fell forward and landed on knee and hands.”  On that same date, the employee underwent a preoperative examination by her primary physician, and the following day, on August 25, 2005, Dr. Holien performed an open reduction and internal fixation of the employee’s left patella.  On August 31, 2005, the employee completed an “Employee’s Report of Claim” for the employer, on which she explained that the injury had occurred as she was “[w]alking to get a grocery cart for hauling cardboard when my foot stuck to the floor causing me to fall forward.  I tried to catch the cart to break my fall.  I landed on my left knee causing injury to my knee cap.”  Following recovery from her surgery, the employee commenced physical therapy on September 30, 2005, at St. Cloud Orthopedic Associates, Ltd., where records for that date report that the employee was working for the employer on August 18, 2005, “when she slipped, fell, landed on her knee breaking her kneecap.”

In a Notice of Insurer’s Primary Liability Determination filed September 7, 2005, the employer and its insurer denied liability for the injury, on grounds that a surveillance tape had revealed that it resulted from a twisted right ankle and that therefore the “Injury Is Idiopathic.”  Eventually, on December 23, 2005, the employee filed a claim petition, alleging entitlement to temporary total disability benefits continuing from August 19, 2005, to over $4,500.00 in medical benefits plus various undetermined medical benefits, and to rehabilitation benefits, all consequent to a work injury on August 18, 2005.  In their answer to that petition, filed January 11, 2006, the employer and its insurer again denied liability for the injury, on grounds that it did not arise out of the employee’s employment with the employer.  Due to her injury and subsequent surgery, the employee was off work from August 19, 2005, through about April 16, 2006, over which period of time she incurred various related medical expenses.  On September 29, 2006, Dr. Holien completed a Health Care Provider Report, on which he reported again that the employee “slipped and fell on stairs and landed on her left knee,” indicating that she had reached maximum medical improvement with regard to her injury on July 27, 2006.

The matter came on for hearing on April 5, 2007.  Issues at hearing included whether or not the employee’s left knee injury of August 18, 2005, arose out of and in the course of her employment with the employer and, if so, the employee’s entitlement to temporary total disability benefits from August 19, 2005, through April 16, 2006, her entitlement to various medical benefits including payment for left knee surgery, and her entitlement to a rehabilitation consultation.  The employee testified at hearing that the fall that resulted in her injury was precipitated by one or both of her feet sticking to the floor by what she supposed to be a fresh floral preservative.  Other evidence submitted at hearing included a routine security surveillance tape on which the employee’s injury was coincidentally captured, together with testimony from the employer’s store manager, Clair Rodgers, and the employee’s supervisor, Jane Oleen.  Mr. Rodgers testified in part that, in his experience, it had happened in the past that people’s feet had gotten stuck on the floor at the employer due to substances like spilled soda pop in the pop aisle, but he was not aware of preservative ever being spilled on the floor in the floral department, though that was certainly possible.  Mr. Rodgers testified further, upon viewing the surveillance video, that the floor where the employee fell appeared to be clean and “[i]t looks like [the employee] tripped on her foot.”  Ms. Oleen, who expressly characterized the employee as reliable and trustworthy, testified in part that, from what she could see on the surveillance video, “My observation is that [the employee’s] ankle turned and she fell.  It looks like it twisted and she went down.”

By amended findings and order filed June 26, 2007, the compensation judge concluded that the employee’s left knee injury did arise out of and in the course of her employment as a result of her foot sticking to the floor at the time of her fall.  In support of that conclusion, the judge indicated expressly, in both his findings and his memorandum, that he found the employee to be a very credible witness, emphasizing the employee’s very good to excellent employment evaluations and her reputation for reliability and trustworthiness.  In his memorandum, the judge asserted also that, even if the employee had simply tripped over her own foot as the employer and insurer had argued, rather than experienced her foot sticking to the floor, the employee’s injury would still be compensable, in that her tripping would be the equivalent of mere negligence, which would not be a basis for denying her claim.  The employer and insurer appeal.

In reviewing cases on appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1 (1992).  Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.”  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, “[f]actfindings are clearly erroneous only if the reviewing court on the entire evidence is left with a definite and firm conviction that a mistake has been committed.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).  Findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of the evidence or not reasonably supported by the evidence as a whole.”  Id.

In order to be compensable under Minnesota workers’ compensation law, a personal injury must be one “arising out of and in the course of” the worker’s employment.  Minn. Stat. § 176.011, subd. 16.  It is uncontested that the employee’s injury in this case occurred “in the course of” the employee’s employment, in that it occurred on the employer’s premises during the employee’s working hours.  See Nelson v. City of St. Paul, 249 Minn. 53, 56, 81 N.W.2d 272, 276, 19 W.C.D. 120, 123 (1957) (“The phrase ‘in the course of’ employment refers to factors of time and place and means that an injury to be compensable must arise within the time and space boundaries of the employment.”).  The compensation judge found that the employee’s injury in this case also “arose out of” the employee’s work, as a result of her foot sticking to the floor and then her knee striking the floor in the process of her attempting to retrieve a cart for use in performing her job.  The judge further concluded, in his memorandum, that, even if the employee’s fall and consequent injury had resulted from a mere trip over her own foot instead of from her foot sticking to the floor, the injury would still have arisen out of the employee’s employment.  The employer and insurer contend that the judge’s finding that the employee’s injury resulted ultimately from her foot sticking to the floor is unsupported by substantial evidence and that the judge erred also as a matter of law in concluding that the injury would still be compensable even if it had resulted from a mere trip.

In concluding that the employee’s fall and consequent knee injury resulted ultimately from the employee’s foot sticking to the floor, the compensation judge relied heavily on the employee’s own testimony, which the judge expressly noted in his memorandum to be “very credible” (underscoring in the original), together with various employment and medical documents completed soon after the employee’s injury, which reiterate that mechanism of injury.  The employer and insurer contend that the judge’s decision attributes excessive weight to the employee’s credited testimony, in that virtually all of the documentation identified by the judge as corroborating the employee’s theory of the injury only reiterates the employee’s personal perception of what happened.  They argue that, since the employee’s honesty is not being contested, any documentation of the consistency of her perception of what happened is irrelevant and virtually meaningless as corroboration of what actually did happen.  They argue that an employee has the burden of proving entitlement to benefits by a preponderance of the evidence and that, however honest it might be, an employee’s mere testimony as to her recollection of events does not, standing alone, prove the actual occurrence of those events.  They argue that in this case there is no evidence independent of the employee’s own perception to corroborate and so prove that her foot actually did stick.  Such a lack of evidence is particularly defeating here, they argue, in that the employee offered no evidence that her shoes had ever “stuck” earlier in the day or ever stuck again later in the day, either due to something on the floor at the employer or due to something on her shoes themselves.  Absent more substantial evidence that the employee’s foot actually did stick to the floor immediately prior to her fall, they argue, the employee has failed to satisfy the requirement that her injury resulted from an “increased risk” to which she was subject as a result of her employment.  See Nelson, 249 Minn. at 55, 81 N.W.2d at 275, 19 W.C.D. at 123 (1957) (“The requisite causal connection [to the work] is supplied if the employment . . . exposes the employee to an external hazard whereby he is subjected to a different and greater risk than if he had been pursuing his ordinary personal affairs.”).  We are not persuaded.

Notwithstanding the employer and insurer’s suggestion, we know of no case law or other law implying that a single witness’s credited testimony as to what he or she perceived is not evidence sufficient of itself to serve as the basis for a finding of fact as to the matter asserted by the witness.  As judicial credence of expert medical testimony has repeatedly demonstrated, credibility is not merely a matter of honesty but just as often a matter of fullness of information and accuracy of observation.  In this case, the employee was the witness most immediately familiar with the details of her injury and the one arguably best positioned to assess the mechanism of its occurrence.  Store manager Rodgers had testified that it was not unprecedented for an individual’s shoe to stick to the floor at the employer, and, particularly absent any question by the employer and insurer as to the employee’s honesty, it was not unreasonable for the compensation judge to rely on the employee’s perceptions.  The employee’s own live testimony in this context, supported by Mr. Rodgers’ testimony that such foot sticking was not unprecedented, was prima facie evidence of the fact asserted, subject to refutation by the employer and insurer.  We have reviewed carefully the surveillance video offered into evidence by the employer and insurer, and we conclude that it manifests no definitive evidence contrary to the perception of the employee sufficient to refute her expressly credited testimony.  Indeed, the two witnesses for the employer and insurer were themselves inconsistent in what they perceived the video to reveal, Mr. Rodgers testifying that it appeared to him that the employee “tripped on her foot” and Ms. Oleen testifying that it appeared to her that the employee twisted her ankle.  Moreover, the employer and insurer have reasonably not contested the compensation judge’s dismissing^[2] as erroneous the lone medically reported mechanism of injury contrary to that asserted by the employee - - that by Dr. Holien.

In Bohlin v. St. Louis County/Popeming Nursing Home, this court states as follows: