The Forgotten Joint Score-12 (FJS-12) is a joint-specific PROM built around the idea that the ultimate goal of joint surgery is a joint the patient no longer notices. This page explains what the FJS-12 is, what it measures, the questions it contains, how it is scored, and how it is used.
What is the Forgotten Joint Score?
The Forgotten Joint Score-12 (FJS-12) is a 12-item self-reported questionnaire that measures a patient's awareness of a joint during everyday activities. It was developed by Behrend and colleagues and published in 2012, with the concept that "forgetting" an artificial joint, that is, having low joint awareness, represents an excellent outcome. It is most commonly used after total hip and total knee arthroplasty and has also been studied in other joint and soft-tissue procedures.
What does the FJS-12 measure?
The FJS-12 measures joint awareness, the degree to which a patient is conscious of their joint during a range of activities of daily living, recreation, and rest. It was specifically designed to discriminate among patients who already have good-to-excellent function, an area where many other scores show ceiling effects.
What questions are included in the FJS-12?
The questionnaire asks patients how often they are aware of their joint in 12 situations, such as in bed at night; sitting on a chair for more than an hour; walking for more than 15 minutes; taking a bath or shower; travelling in a car; climbing stairs; walking on uneven ground; standing up from a low-sitting position; standing for long periods; doing housework or gardening; taking a walk or hiking; and doing a favorite sport.
How is the FJS-12 scored?
Each item is answered on a five-point scale scored 0 to 4 (never, almost never, seldom, sometimes, mostly). Responses are summed and divided by the number of completed items, and the mean is multiplied by 25 to create a 0-to-100 scale. The direction is set so that higher scores indicate less joint awareness and a better outcome. If more than four items are missing, a total score should not be calculated.
How is the FJS-12 used in clinical practice?
Surgeons use the FJS-12 to evaluate outcomes after joint replacement, particularly to distinguish between good and excellent results. It has demonstrated high internal consistency and a low ceiling effect. Published research in total knee arthroplasty has reported a minimal clinically important difference in the range of roughly 11 to 14 points, which can help clinicians interpret whether a change in score is meaningful.
Strengths and limitations
The FJS-12's strengths are excellent internal consistency, a low ceiling effect, and strong ability to differentiate high-functioning patients. Limitations include a potential floor effect in patients with poor function and, in some populations, a ceiling effect emerging at longer follow-up. It is registered for free clinical use but access may require registration with the developers.
Frequently asked questions
What is a good Forgotten Joint Score? Scores range from 0 to 100, and higher is better; a high score means the patient rarely notices the joint.
How many questions are on the FJS-12? There are 12 items, each scored from 0 to 4.
What joints is the FJS-12 used for? It is most commonly used for the hip and knee after joint replacement and has been studied in additional joint procedures.
References
- Behrend H, Giesinger K, Giesinger JM, Kuster MS. The "Forgotten Joint" as the ultimate goal in joint arthroplasty: validation of a new patient-reported outcome measure. Journal of Arthroplasty. 2012;27(3):430-436.
- Hamilton DF, Loth FL, MacDonald DJ, et al. Validation of the English language Forgotten Joint Score-12 as an outcome measure for total hip and knee arthroplasty in a British population. Bone & Joint Journal. 2017;99-B(2):218-224.
- Giesinger JM, Behrend H, Hamilton DF, Kuster MS, Giesinger K. Normative Values for the Forgotten Joint Score-12 for the US General Population. Journal of Arthroplasty. 2019;34(4):650-655.
