Aggravation of pre-existing condition or injury is a typical defense used by workers’ compensation insurance companies to deny valid claims.  It is not a strong defense in most cases and an experienced, knowledgeable attorney knows how to deal with it.  An employer takes an employee as is, and the employee’s pre-existing condition or predisposition to injury does not relieve the current employer from liability for worker’s compensation. Semons Dep’t Store v. DILHR, 50 Wis. 2d 518 (1971).

On pre-existing injury, the best case in Wisconsin workers comp law is Lewellyn v. DILHR, 38 Wis. 2d 43 , 155 N.W.2d 678 (1968), which groups aggravations of preexisting conditions caused by a new work accident into the following three categories:

1) Definite breakage, regardless of pre-existing condition:

If there is a definite “breakage” (a letting go or a structural change like a herniated disc as described by Professor Larson), while the employee is engaged in usual or normal activity on the job, and there is a relationship between the breakage and the effort exerted or motion involved, the injury is compensable regardless of whether or not the employee’s condition was preexisting and regardless of whether or not there is evidence of prior symptoms or treatment.

2) Mere manifestation of a preexisting condition, with no definite breakage:

If the employee is engaged in normal exertive activity but there is no definite “breakage” or demonstrable physical change occurring at that time but only a manifestation of a definitely preexisting condition of a progressively deteriorating nature, recovery should be denied even if the manifestation or symptoms of the condition became apparent during normal employment activity.

3) Precipitation, aggravation, and acceleration, beyond normal progression, of a preexisting condition, regardless of definite breakage:

If the work activity precipitates, aggravates and accelerates beyond normal progression, a progressively deteriorating or degenerative condition, it is an accident causing injury or disease and the employee should recover even if there is no definite “breakage.”  This is question 12 on the WKC-16B form and should not be confused with question 13, which asks about a condition or injury that occurs over time not from a single traumatic incident.

In Joseph Schlitz Brewing Co. v. DILHR, 67 Wis. 2d 185, 192 (1975) , the court held that the conditions of the third category in the Lewellyn rule constitute a three-part requirement, all three parts of which–precipitation, aggravation, and acceleration beyond normal progression–must be found by the doctor.  This is complicated and an attorney who does this work for a living is best suited to ask the doctor these key questions.  McCormick Law Office in Milwaukee, Wisconsin takes great care and time to develop the questions the doctor or surgeon must answer.