Functional performance differences between the Genium and C-Leg prosthetic knees and intact knees

Abstract

Abstract-Microprocessor prosthetic knees (MPKs) have advanced technologically, offering new features to decrease impairment and activity limitations for persons with transfemoral amputation (TFA). The Genium knee is functionally untested, and functional differences between it and intact knees are unknown. This study sought to determine whether Genium use improves functional performance compared with the C-Leg. A randomized experimental crossover design was used, with a cross-section of five nonamputee controls for comparison to normal. Twenty community-ambulating persons with TFA were trained and tested for accommodation with study components. All subjects (n = 25) were assessed using the Continuous-Scale Physical Functional Performance-10 (CS-PFP10) assessment. Subjects with TFA used both MPK systems. Genium use improved upper-body flexibility, balance, and endurance domain scores (7.0%-8.4%, p </= 0.05) compared with the CLeg. Only in the endurance domain did Genium users score significantly lower than nonamputees (22.4%, p = 0.05). Comparing the C-Leg with nonamputees, CS-PFP10 total (2.0%-24.4%, p = 0.03) and all domains except upper-body strength were lower than nonamputees (-13.4% to -28.9%, p </= 0.05). Nonetheless, regardless of knee condition, subjects with TFAs did not equal or surpass nonamputees in any functional domain, suggesting room for improvements in TFA functional performance.

Effects of the Genium Knee System on Functional Level, Stair Ambulation, Perceptive and Economic Outcomes In Transfemoral Amputees

“…Subjects achieved significantly higher ( p < 0.05) function with Genium use (4). Using these measures of function, incremental cost-effectiveness of Genium vs. C-Leg ranged from $6,000 to $6,522 per unit increase in function (END & UBF and BAL respectively) assuming a $30,000 difference in cost (Figure 1).…”

“…These costs also presume that each unit of functional increase occurs in isolation. However, this is not the case, as each of these units of functional gain occurred simultaneously (4), thereby increasing value.…”

“…A previous report of the current randomized control trial analyzed function in activities of daily living using the Continuous Scale-Physical Functional Performance-10 assessment (CS-PFP-10), a measure shown to be valid, reliable, and sensitive to change in multiple diagnostic populations, including TFA patients (4,17-19). Incremental cost effectiveness ratios (ICER) were calculated using differences in scores for each of three domains (balance & coordination (BAL), upper body flexibility (UBF), and endurance (END)) that were significantly improved ( p ≤ 0.05) when subjects used Genium compared with C-Leg on the CS-PFP-10 as source data for effects (denominator).…”

“…An example is that some practitioners within the private sector receive volume purchasing discounts based on the size of their practice, and, further, federal sector practitioners may also receive discounted component costs. Uncertainty with the difference in performance was addressed by only using the domain score differences that were both improved and statistically significant from our previously published work (4). This was important given that Genium improved all domains of the CS-PFP-10, but not all domains were significantly improved.…”

“…Recently, the Genium MPK system has demonstrated improvements in perceived functional measures (2), knee kinematics (3), and physical functional performance (4) compared to C-Leg. Clinimetric assessment and health economic analysis have not yet been conducted.…”