In some cases the incapacitating effects of a compensable condition may be actually removed or annulled by a later non-compensable injury or disease.
Entitlements in respect of a wholly incapacitating medical condition do not cease merely because the client subsequently develops an additional non-compensable condition of greater severity. An entitlement to weekly payments continues while the incapacitating effects of that original condition also continue. That scenario is explained in detail at 20.10.
Nevertheless, in rare circumstances an incapacitating condition can be overtaken and the entitlement to incapacity payments terminated by the effects of a new event. That 'new event' may of course include a new injury. This concept is referred to in the relevant case law as 'novus actus interveniens'. It applies where the nature of (or the effects of) that new injury or disease actually removes incapacity for work imposed by the first condition. In the case Re Sadek and Commonwealth (1988) the Tribunal said:
'Before the novus actus will be regarded as the only cause of the incapacity, it must be shown that the incapacity which would have resulted from the injury has ceased to exist and that the incapacity which does exist has resulted from the new cause as the sole cause'
For instance, if the Commonwealth was paying weekly compensation in respect of a knee injury and subsequently a non-compensable MVA resulted in the amputation of that whole leg at the hip, the requirement to pay incapacity payments in respect to the knee would also have been removed.
Similarly, incapacity 'top up' payments made in respect to poorly explained back pain from a relatively minor injury may be terminated by the advent of a second, totally incapacitating but non-compensable injury to a wide area of the spine i.e. including the site of the previous injury. Novus actus would clearly apply where the new incident inflicted serious damage to the vertebral level previously injured, i.e. to the point where the previous lesions can not be separately detected.