Revision in previously satisfied knee arthroplasty patients is the result of their call on the physician, not on pre-planned follow-up: a retrospective study of 181 patients who underwent revision within 2 years.

Background: Degree of satisfaction with a knee arthroplasty is said to be correlated to reduced pain and better function. During a validation of the Swedish Knee Arthroplasty Register in 1997, previously operated patients were asked how satisfied they were with their knee. A subgroup of "satisfied" patients was identified who underwent revision within 2 years of having expressed satisfaction. Our aim was to study the revision diagnosis, to determine whether the problem leading to revision had been discovered as a result of routine follow-up, and also to find out when the symptoms leading to revision had started.

Methods: We retrospectively studied the medical records of 181 patients (181 knees), with a median age of 74 (31-88) years. 68% were women and the median time between primary operation and revision was 8 (3-21) years.

Results: Aseptic loosening (74/181) was the most common diagnosis. 2 cases were revised as a result of routine follow-up. 44% of the medical records included reports of pain in the replaced knee prior to answering the satisfaction questionnaire.

Interpretation: Few patients were admitted to knee revision surgery due to medical findings discovered during routine follow-up. The term "satisfaction" must be interpreted with care, as it seems to have a more complex meaning for the patients than absence of knee pain.