A New High-flexion Knee Scoring System to Eliminate the Ceiling Effect

Abstract

Background Various scoring systems document improvement after TKA, but most are associated with a ceiling effect that may fail to distinguish between patients having different levels of knee function after TKA. We therefore developed a new scoring system for patients with higher levels of flexion to eliminate ceiling effects observed with current systems. Questions/purposes The purposes of this study were (1) to determine whether the high-flexion knee score eliminates the ceiling effect, (2) to assess the validity and responsiveness of the high-flexion knee score, and (3) to determine whether the high-flexion knee score can aid in differentiation of the knee status of patients at the ceiling level. Methods We prospectively studied 165 patients with 201 well-functioning knees who had undergone primary TKA. We obtained Knee Society scores, WOMAC scores, Feller scores, SF-36 scores, and high-flexion knee scores for all patients. The high-flexion knee score includes items that reflect knee function in the high functional range, such as sitting on or rising from the floor, squatting, or kneeling. We determined the ceiling effects and score distributions of various scoring systems. We performed a convergent validity test of the high-flexion knee score by correlation analysis with these various scoring systems. Responsiveness of the high-flexion knee score was assessed by correlation analysis of changes in various scoring systems. To determine whether the high-flexion knee score can aid in differentiation of knee status of patients at the ceiling level, relative responsiveness of the various scores in the ceiling versus below the ceiling range was determined. Results The high-flexion knee score showed no ceiling effect, whereas the other systems did. Addition of the highflexion knee score to the other scoring systems eliminated these ceiling effects and resulted in more normalized score distributions. The high-flexion knee score correlated (r = À0.77) with WOMAC in postoperative scores, and it also correlated with the changes in WOMAC (r = À0.69) and SF-36 physical functioning (r = 0.62).

Correlations Between Functional Knee Outcomes and Health-Related Quality of Life After Total Knee Arthroplasty in an Asian Population

“…In patient demographics, there was an inordinately larger proportion of females (80%) in this study, but this is likely due to a greater utilization of health care and life expectancy of females than males, in addition to the higher prevalence of OA. This was similarly reflected in other studies in the Asian population [16,20]. It was also interesting to note that the mean BMI of patients was high (28.2 ± 5.7) with 74% of the study population being overweight or obese.…”

“…All parameters show statistically significant improvement (P < .05) with the exception of GH component of SF-36 achieving only a mean difference of 2 points (P ¼ .221). In addition, it is noted that even though statistical [20]. Tables 3 and 4 show the correlation between changes in KSS and OKS scores vs the changes in the summary and subscale scores of SF-36, respectively.…”

WITHDRAWN: Early Patellofemoral Function of Unilateral TKA with Medial Pivot Prostheses is Superior than with Conventional Posterior-Stabilized Prostheses

“…In the present study, group B performed superior to group A in terms of postoperative activity improvement, while the improvement in the Kujala score in group A was better than in group B; however, similar KSS and WOMAC scores were recorded in the two groups. There are two hypotheses for this similarity between the groups: one, knee mobility may be taken into account in the KSS and WOMAC scores, compensating for the deficiency in the Kujala score in group B; two, the KSS and WOMAC clinical scoring systems may have been subjected to a ceiling effect [43], resulting in the scoring systems not being sensitive enough to determine between-group differences.…”

Midterm clinical and radiographic results of the medial pivot total knee system

“…While a previous study has shown the subject system was preferred by bilateral subjects over other TKA designs implanted in the contralateral knee [10], scores in the present study were not noticeably different than those reported by for other devices. This was expected, as the ceiling effects of the Knee Society score likely prevent it from being sensitive enough to determine if differences exist between TKA designs [11].…”