Forgotten Joint Score-12 After Unicompartmental Knee Arthroplasty: Comparative Analysis of the Bulgarian Cohort with International Studies

Abstract

The Forgotten Joint Score-12 has emerged as one of the most sensitive patient-reported outcome measures currently available for evaluating postoperative joint awareness following knee arthroplasty. Unlike traditional instruments focused primarily on pain and functional limitation, the FJS-12 evaluates the extent to which patients remain consciously aware of their prosthetic joint during routine daily activities. This concept is particularly relevant in unicompartmental knee arthroplasty, where preservation of native ligamentous structures and physiological knee kinematics frequently leads to high postoperative functional outcomes and elevated patient expectations. The Bulgarian version of the FJS-12 was recently translated, culturally adapted, and validated in patients undergoing UKA. In the present study we compare postoperative joint awareness outcomes in the Bulgarian UKA cohort with those reported in previously published international UKA studies using the FJS-12 and discuss the clinical relevance of the FJS-12 in high-functioning UKA populations. We found that the Bulgarian FJS-12 demonstrates favorable psychometric performance and appears particularly suitable for evaluating postoperative joint awareness in UKA populations. Comparison with previously published UKA cohorts supports the clinical relevance and cross-cultural reproducibility of the instrument in high-functioning arthroplasty patients.