We proceed now to the question of Second Injury Fund liability. Section 287.220 RSMo creates the Fund and provides when and what compensation shall be paid in "all cases of permanent disability where there has been previous disability." As a preliminary matter, employee must show that he suffers from "a preexisting permanent partial disability whether from compensable injury or otherwise, of such seriousness as to constitute a hindrance or obstacle to employment or to obtaining reemployment if the employee becomes unemployed ..." Id. We have determined that employee suffered from preexisting permanent partially disabling conditions referable to a preexisting right knee injury and morbid obesity. The Missouri courts have articulated the following test for determining whether a preexisting disability constitutes a "hindrance or obstacle to employment":
[T]he proper focus of the inquiry is not on the extent to which the condition has caused difficulty in the past; it is on the potential that the condition may combine with a work-related injury in the future so as to cause a greater degree of disability than would have resulted in the absence of the condition.
Knisley v. Charleswood Corp., 211 S.W.3d 629, 637 (Mo. App. 2007) (citation omitted).
We note Mr. England's testimony that employee did not identify any specific past difficulty that made obesity a "hindrance or obstacle" to him prior to August 5, 2001. Transcript, page 478. But as the Missouri courts have made clear, past difficulties are not determinative. Wuebbeling v. West County Drywall, 898 S.W.2d 615, 620 (Mo. App. 1995). Rather, we must apply a "potential to combine" analysis. See Knisley v. Charleswood Corp., 211 S.W.3d 629, 637 (Mo. App. 2007); Concepcion v. Lear Corp., 173 S.W.3d 368, 371 (Mo. App. 2005); E.W. v. Kan. City Sch. Dist., 89 S.W.3d 527, 538 (Mo. App. 2002); and Carlson v. Plant Farm, 952 S.W.2d 369, 373 (Mo. App. 1997). When we apply the appropriate standard, as identified in Wuebbeling and consistently reaffirmed by the courts, we conclude that employee's preexisting obesity amounted to a hindrance or obstacle to employment at the time he sustained the primary injury. This is because we are convinced a cautious employer could reasonably perceive employee's obesity as having the potential to combine with a work related injury so as
to produce a greater degree of disability than would occur in the absence of such condition. Accordingly, we conclude employee's obesity was serious enough to constitute a hindrance or obstacle to employment for purposes of $\S 287.220 .1$.
Similarly, we conclude employee's preexisting right knee injury was serious enough to constitute a hindrance or obstacle to employment. The very facts of this case demonstrate that this condition not only had the potential to combine with a subsequent injury to result in increased disability, but that it actually did so when employee suffered the August 2001 primary injury.
The only remaining question is whether employee satisfied the statutory requirements for proving that the Second Injury Fund is liable for permanent total disability benefits. To establish Fund liability for permanent total disability benefits, employee must prove that: (1) he suffered a permanent partial disability as a result of the last compensable injury; and (2) that disability has combined with the prior permanent partial disability to result in total permanent disability. ABB Power T \& D Co. v. Kempker, 236 S.W.3d 43, 50 (Mo. App. 2007). Section 287.220.1 requires us to first determine the compensation liability of the employer for the last injury, considered alone. If employee is permanently and totally disabled due to the last injury considered in isolation, the employer, not the Second Injury Fund, is responsible for the entire amount of compensation. Landman v. Ice Cream Specialties, Inc., 107 S.W.3d 240, 248 (Mo. 2003).
We have adopted the administrative law judge's finding that, as a result of the last injury, employee sustained a 50 % permanent partial disability of the right knee. We have credited Mr. England and found that the primary injury, considered in isolation, did not render employee permanently and totally disabled, but that employee is permanently and totally disabled due to his preexisting disability as it existed on August 5, 2001, in combination with the disability stemming from employee's injuries sustained on that date.
In light of the foregoing findings and conclusions, we modify the award of the administrative law judge with respect to the issue of Second Injury Fund liability. We conclude employee met his burden of establishing Second Injury Fund liability for permanent total disability benefits under § 287.220.1.