We identified a group of patients from the Swedish Arthroplasty Register who reported no relief of pain or worse pain one year after a total knee replacement (TKR). A total of two different patient-reported pain scores were used during this process. We then evaluated how the instruments used to measure pain affected the number of patients who reported no relief of pain or worse pain, and the relative effect of potential risk factors.
Between 2008 and 2010, 2883 TKRs were performed for osteoarthritis in two Swedish arthroplasty units. After applying exclusion criteria, 2123 primary TKRs (2123 patients) were included in the study. The Knee injury and Osteoarthritis Outcome Score (KOOS) and a Visual Analogue Scale (VAS) for knee pain were used to assess patients pre-operatively and one year post-operatively.
Only 50 of the 220 patients (23%) who reported no pain relief on either the KOOS pain subscale or the VAS for knee pain did so with both of these instruments. Patients who reported no pain relief on either measure tended to have less pain pre-operatively but a higher degree of anxiety. Charnley category C was a predictor for not gaining pain relief as measured on a VAS for knee pain.
The number of patients who are not relieved of pain after a TKR differs considerably depending on the instrument used to measure pain.
Cite this article: Bone Joint J 2014;96-B:1222–6.
Author contributions: AWD: study design, data selection and data analysis. MS: study design and data selection. LL: study design. JR: study design and data analysis. OR: study design and data selection. All authors prepared the manuscript and read and approved the final manuscript.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article was primary edited by A. C. Ross and first proof edited by G. Scott.
- Received October 18, 2013.
- Accepted June 18, 2014.
- ©2014 The British Editorial Society of Bone & Joint Surgery