Introduction and aim of investigation:
Osteoarthritis (OA) of the knee joint(s) as a
consequence of occupational factors has
recently been defined as an occupational
disease in Germany (BK 2112). To date only
limited experience is available for the evaluation
of patients who claim to suffer from this
occupational disease. A specific, commonly
accepted clinical picture for this occupational
disease does not exist. Concomitant factors
affecting development of OA complicate
decision finding. This leads to considerable
uncertainty in the process of acceptance or
rejection of an occupational cause of OA in
any specific case. In this paper we have attempted
to design an algorithm for the examination
of patients and a description of
the relationship between the clinical picture
and the physical strain and so to provide a
basis for decision finding.
Collective and method: Within a period
of 18 months, 97 men with different jobs in
construction work were evaluated for occupational
disease BK 2112. Every single case
had to fulfil the criterion of having worked
for 13 000 hours in knee flexion under conditions
of physical stress during their life-time,
at least 1 hour per day. Anamnestic data
(family and personal history, KOOS score)
were recorded and physical and serological
examination as well as radiographs of both
knees in three views were performed. In addition
all knees were examined by means of
MRI scans. Correlation analysis was carried
out for all parameters (software SPSS 11.5.1,
Kendall rank correlation coefficient).
Results: In 10 cases the formal preconditions
were not fulfilled (less than 13000 hours). In
15 cases the knee joints had already been
replaced by total arthroplasty. Nevertheless
all probands were included in the correlation
analysis as far as possible. The only highly significant
correlation (p = 0.00001) found was
between radiological and MRI findings. Slight
correlation was found between the KOOS
score and alterations seen in conventional
X-rays and MRI. Also concomitant factors
showed weak correlations with these alterations
in X-rays and MRI, the body mass index
moreover correlated with the KOOS score.
Despite this, no correlation could be demonstrated
between occupational parameters
(cumulative hours of activity involving strain
on the knees) and any other factors.
Conclusion: A general recommendation
can be formulated for the use of MRI when
occupational osteoarthritis is suspected.
In any case, for the assessment of the existence
of occupational disease OA (BK 2112),
occupational anamnesis, clinical analysis of
knee joint symptoms, radiological and MRI
findings must all be taken into account. Critical
analysis of all the data suggests that MRI
plays a key role in the detection of initial
cartilaginous changes. At the moment it is
difficult to define a specific combination of
findings which would indicate the existence
of occupational disease OA (BK 2112) beyond
any reasonable doubt.
