Radiosynoviorthesis for treating recurrent joint effusions after endoprosthetic knee replacement

Radiosynoviorthesis (RSO) has been established as a treatment modality for rheumatoid arthritis. Other forms of joint diseases like recurrent joint effusions after knee arthroplasties are under investigation. The aim of this study was to examine whether RSO therapy is effective in the application of an endoprosthesis and whether there are common causes of failure.

Between 1998 and 2005, 55 patients received RSO treatment (90Y colloid) for recurrent joint effusions after endoprosthetic knee replacement. A total of 46 patients were followed up and questioned anonymously according to a modified Knee Society Knee Scoring System (KSS) and Hospital for Special Surgery score. On the basis of patient records, a subgroup analysis of patients with revision surgery after RSO (subgroup A) and without further operative interventions (subgroup B) was performed.

Subgroup A comprised 46% (21/46) and subgroup B comprised 54% (25/46) of all patients. Most patients from subgroup A did not benefit from RSO. Of these 21 patients, 7 presented with low-grade infection, 7 presented with signs of endoprosthetic loosening, 2 presented with metal allergy, and 2 had undergone revision because of trauma.Patients in subgroup B experienced a significant improvement in pain (KSS score, from 22.5 to 34 points) and function (KSS score, from 62.9 to 77.3 points; Hospital for Special Surgery score, from 30.2 to 38.7) after RSO.

Radiosynoviorthesis resulted in an improvement in pain and function in ∼50% of patients with knee endoprostheses. In 85% of all patients, in whom RSO treatment failed, endoprosthetic complications like infection, loosening, allergy, and trauma were detected. In conclusion, RSO is a valid therapeutic option for joint effusions after knee arthroplasties. However, if RSO fails, a thorough exclusion of endoprosthetic complications should be performed.