Forgotten Joint Score for early outcome assessment after total knee arthroplasty: Is it really useful?

• Published in: Knee Surgery and Related Research, 32(0) Vol. 32; no. 1; pp. 1 - 37
• Main Authors: Lee, Qunn Jid, Chang, Wai Yee Esther, Wong, Yiu Chung
• Format: Journal Article
• Language: English
• Published: London BioMed Central 29-07-2020; BMC; 대한슬관절학회
• Subjects: Arthritis; Bilingualism; Ceiling effect; Dementia; Early results; Floor effect; Forgotten Joint Score; Interpreters; Joint replacement surgery; Joint surgery; Nurse specialists; Orthopedics; Patient report outcome; Patients; Questionnaires; Total knee arthroplasty; Transplants & implants; Triathlon; Validation studies; Validity; 정형외과학; United States > US
• ISSN: 2234-2451; 2234-0726; 1225-1623; 2234-2451
• DOI: 10.1186/s43019-020-00049-0

Abstract
Background
Forgotten Joint Score (FJS) has become a popular tool for total knee arthroplasty (TKA), but almost all studies had assessment performed 1 year after surgery. There is a need for a sensitive tool for earlier outcome assessment. The aim of this study was to investigate the usefulness of FJS within the first year after TKA.
Methods
This was a cross-sectional study. Patients within the first year after primary TKA were recruited. FJS was translated into the local language with a cross-cultural adaptation and was validated by assessing the correlation with the Western Ontario and McMaster Universities Arthritis Index score (WOMAC). Ceiling and floor effects (highest or lowest 10% or 15%) of both scores were compared. Skewness of scores was assessed with a histogram.
Results
One hundred sixty-three subjects were recruited: 84 (51.5%) had evaluation at 3 months after the operation, 56 (34.4%) at 6 months, and 23 (14.1%) at 12 months. FJS had fewer patients at the highest 10% (10.7% vs. 16.1%,
P
 = 0.046) or 15% (19.6% vs. 32.1%,
P
 = 0.027) at 6 months and within the first year overall (6.7% vs. 13.5%,
P
 <0.001; 14.1% vs. 22.7%,
P
 <0.001). Also, it had more patients at the lowest 10% (16.7% vs. 0%,
P
 <0.001) or 15% (21.4% vs. 0%,
P
 <0.001) at 3 months, 6 months (10.7% vs. 0%,
P
 <0.001), and overall (12.9% vs. 0%,
P
 <0.001; 16.6% vs. 0%,
P
 <0.001). The skewness was much less than WOMAC (0.09 vs. −0.56).
Conclusions
FJS has a low ceiling effect but a high floor effect in the first year after TKA. Such characteristics make it less useful for the general assessment of early patient report outcome after operation.