Intramedullary pressure of the patella in Chondromalacia.

Degenerative changes in load-bearing joints are often combined with altered intramedullary circulation. This may cause an alteration in intramedullary pressures. It has been said that articular symptoms are connected with a change in intramedullary pressures being high they are suspected to cause pain. In this investigation the intramedullary pressure has been evaluated in chondromalacia and osteoarthrosis of the patella. A comparison has been made with normal patellae. A biopsy needle was drilled into the intramedullary bone of the patella and connected with a registering unit. In a control group an average value of 19 mm Hg was registered. In the condromalacia group the mean intramedullary pressure was 44 mm Hg and in osteoarthrosis 37 mm Hg.