Arthrofibrosis Associated with Total Knee Arthroplasty: Gray-Scale and Power Doppler Sonographic Findings.

Boldt JG, Munzinger UK, Zanetti M and Hodler J. AJR. 2004;182(2):337-340. [or click here for open access]

This is the editor's interpretation of a paper published in the orthopaedic literature in 2004 - our attempt to make relevant medical articles accessible to lay readers. If you wish to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library.

These authors reference an earlier published study suggesting that the incidence of arthrofibrosis after total knee replacement can range between 1% and 17%. In this study they evaluate the usefulness of gray-scale and power Doppler sonography in identifying arthrofibrosis in total knee replacement patients. It seems to be the first study of its kind.

Their own study included 3000 knee replacements of the 'mobile-bearing' kind all done in the same hospital from 1988 onwards. They identified a subgroup 38 patients in which range of movement (ROM) was much reduced and who had other signs and symptoms highly indicative of arthrofibrosis, and in whom other causes for the symptoms had been excluded. All of these patients had had at least one manipulation under anaesthesia (MUA) and most had had interventional surgery for debridment (cutting away scar tissue).

The sonography was done with the patients lying on their backs with knees bent to 90 degrees while the examiner performed the sonography around the patellar area. The authors give technical details of the procedure if readers are interested in accessing the original article. There was a control group of patients who had also had total knee replacement but who were not arthrofibrotic.

What was found is that there is synovial membrane (the internal joint lining) thickening and increased blood vessels in the arthrofibrotic group. Using the sonography the investigators were able to determine the amount, diameter and localisation of the scar tissue, and were better able to plan their surgery to avoid damage to normal tissues.