The employer and insurer appeal from the compensation judge’s determination that the employee’s personal injury arose out of and in the course of her employment.  We reverse.

On June 23, 2004, Geraldine Lewin was employed as an LPN at the Aspen Medical Group Clinic in Maplewood.  Generally, the employee was assigned to work with one of the clinic’s physicians.  She brought patients back to the examining room from the reception area, she interviewed the patient, and she took blood pressure and vital signs. Her duties also included reviewing the examination room to make sure needed supplies were on hand before putting a patient in the room.  On June 23, as she was walking from the nurse’s station to an examination room, the employee fell, landing on her right knee and injuring it.

The employee had no explanation for her fall.  She did not trip on anything on the floor.  Her right leg or knee did not give out.  She had no pain in her right knee or right leg before her fall.  No explanation for the fall has been provided by any medical provider.

The employee sought medical care after her fall and was diagnosed as having sustained a soft-tissue injury to the right knee with evidence of cartilage contusion of the distal femoral condyle.  She was treated with physical therapy and activity modification.  The employee also missed time from work due to her knee problems.  Initially, the employer and insurer admitted liability for the injury and paid medical and wage loss benefits.

The employer and insurer subsequently filed a Petition to Discontinue Benefits based on an allegation that the employee’s injury did not arise out of her employment.  The petition was heard by Compensation Judge Rolf Hagen on September 29, 2005.  In his Findings and Order of October 24, 2005, the compensation judge determined that the employee’s knee injury was work related and denied the employer and insurer’s petition to discontinue benefits.  The employer and insurer appeal.

For a personal injury to be covered by workers’ compensation, the injury must be one “arising out of and in the course of employment.”  Minn. Stat. § 176.021, subd. 1.  The “course of employment” requirement refers to the time and place of the injury, while the phrase “arising out of” connotes a causal relationship.  Gibberd v. Control Data Corp., 421 N.W.2d 776, 40 W.C.D. 1040 (Minn. 1988).  To establish a causal relationship requires a showing that the injury follows “as a natural incident of the work.”  Foley v. Honeywell, Inc., 488 N.W.2d 268, 271 (Minn. 1992).

In the present case, the reason for the employee’s fall is unknown.  The employee is unable to establish that the fall was a natural incident of her work activity as a nurse and is unable to establish that there was any causal connection between her work activity and the fall.

“Arising out of” employment and “course of employment” are not to be applied independently but are parts of a single test of work connection.  2 Larson’s Workers’ Compensation Law, § 29 (2005).  To that end, a deficiency in one factor may be made up by the strength of the other factor so that, in the end, the injury is found compensable.  Noggle v. Lazer Communications, Inc., slip op, (W.C.C.A. Nov. 10, 2004); Spinks v. Ecowater Sys., slip op, (W.C.C.A. Jan. 21, 2005).  We conclude, however, that we are unable to apply this balancing test in the present case since we are dealing here, not with a deficiency in the evidence showing that the fall was connected to work, but with a total lack of evidence on that question.

Disputed issues are to be determined by preponderance of the evidence.  Minn. Stat. § 176.021, subd. 1(a).  “The claimant has the burden of proving, by a fair preponderance of the evidence, that he or she is entitled to workers’ compensation benefits.”  Fischer v. Saga Corp., 463 N.W.2d 501, 501, 43 W.C.D. 559, 560 (Minn. 1990).

Given the evidence presented in this matter, we conclude that the employee failed to establish that her injury arose out of and in the course of her employment.  The compensation judge is reversed.