Recently, the courts have decided important cases involving the Guides and the issue of apportionment. Two significant cases are presented here.
Pre-existing Impairment and Apportionment
In Vargas v Industrial Com'n of Arizona (926 P.2d 533 [Ariz.App. Div. 1 1996]), the court faced a claimant who had a pre-existing nonwork-related injury to his right knee as well as a work-related injury. At issue was how to apportion out the pre-existing injury. The court held that under Arizona's statute the impairment from the preexisting injury should be subtracted from the current work-related impairment. The court reasoned as follows:
Pre-existing Asymptomatic Condition and Apportionment
The Colorado courts recently addressed the issue of apportionment in a workers' compensation claim where the pre-existing injury was asymptomatic at the time of the work-related injury. The court in Askew v Industrial Claim Appeals Office (927 P.2d 1333 [Colo. 1996]) held that the worker's benefits...