gms | German Medical Science

Questionnaire: It is difficult to find out, in which tissue the pain arises in osteoarthritis. It is obvious that the joint surfaces are not the only structure involved in the disease process. To know which anatomical structure plays which role in the production of symptoms would be helpful in management strategies. This study casts a light on the role of muscle tissue by approaching the topic by means of the of the Myofascial Trigger Point concept. Those Trigger Points as described by Travell and Simons are well defined tender areas within a muscle whose manual compression “triggers” a very characteristic referred pain.

Methods: 50 consecutive patients, aged 56 to 82 years, suffering from Medial Osteoarthritis of the Knee with pain manifestation on the medial side of the knee were included. The medial head of M. gastrocnemius has 2 potential triggerpoints. They are localized in the popliteal area. In case of their presence they were infiltrated either with steroids as a single treatment or with NaCl in a series of 5 infiltrations. To be sure to hit the intended muscle the infiltration was done under ultrasound control. Other muscles were examined as well with regard to Myofascial Trigger Points. They were Soleus, Vastus medialis, medial and lateral hamstrings. These other trigger points were not addressed with treatment. Thus a certain distinction on the importance of the different muscle groups as to the source of pain becomes possible. The pain intensity was measured with the help of the Visual Analogue Scale (VAS) before the infiltration, after every treatment session and on every follow up presentation. A statistically viable control group of 50 patients was formed who don't suffer from osteoarthritis of the knee in order to make sure that they don't show the respective trigger points.

Results and conclusions: In all patients one or both of the 2 Gastrocnemius triggerpoints were present and consequently infiltrated. All patients had immediate pain reduction to different extent, but mostly to the patients' satisfaction. On average the VAS dropped from 7 to 2. The follow up is at present 1 week to 6 months. Infiltration of the actually involved of the two trigger points of the medial head of M. gastrocnemius is a very effective pain management. This means on the one hand that it is an alternative to intraarticular injection. On the other hand the study supports the view that the joint surfaces are not the only source of complaints in osteoarthritis. Another extremely important anatomical structure producing pain in that context is muscle tissue. In medial osteoarthritis of the knee the medial head of M. gastrocnemius seems to play a crucial role. This has implications for operative management strategies.