Key legal question
Whether the stair incident of 11 January 2004 constituted an accident or analogous bodily injury under UVG/ATSG.
Extracted holding
The incident lacked the required external factor; it was a giving-way episode caused by an internal knee instability, not an accident or analogous bodily injury.
Extracted reasoning
Treppensteigen is an ordinary bodily movement without increased risk. The claimant described only knee buckling/slipping, not an external event such as slipping or falling. The medical record showed a pre-existing severe knee instability, so the causal factor was internal.