Does Use of a Powered Ankle-foot Prosthesis Restore Whole-body Angular Momentum During Walking at Different Speeds?

Abstract

Background Whole-body angular momentum (H) influences fall risk, is tightly regulated during walking, and is primarily controlled by muscle force generation. People with transtibial amputations using passive-elastic prostheses typically have greater H compared with nonamputees. Questions/purposes (1) Do people with unilateral transtibial amputations using passive-elastic prostheses have greater sagittal and frontal plane H ranges of motion during walking compared with nonamputees and compared with using powered prostheses? (2) Does use of powered anklefoot prostheses result in equivalent H ranges in all planes of motion compared with nonamputees during walking as a result of normative prosthetic ankle power generation? Methods Eight patients with a unilateral transtibial amputation and eight nonamputees walked 0.75, 1.00, 1.25, 1.50, and 1.75 m/s while we measured kinematics and ground reaction forces. We calculated H for participants using their passive-elastic prosthesis and a powered anklefoot prosthesis and for nonamputees at each speed. Results Patients using passive-elastic prostheses had 32% to 59% greater sagittal H ranges during the affected leg stance phase compared with nonamputees at 1.00 to 1.75 m/s (p \ 0.05). Patients using passive-elastic prostheses had 5% and 9% greater sagittal H ranges compared with using powered prostheses at 1.25 and 1.50 m/s, respectively (p \ 0.05). Participants using passive-elastic prostheses had 29% and 17% greater frontal H ranges at 0.75 and 1.50 m/s, respectively, compared with nonamputees (p \ 0.05). Surprisingly, patients using powered prostheses had 26% to 50% greater sagittal H ranges during the affected leg stance phase compared with nonamputees at 1.00 to 1.75 m/s (p \ 0.05). Patients using powered prostheses also had 26% greater frontal H range compared with nonamputees at 0.75 m/s (p \ 0.05). Conclusions People with a transtibial amputation may more effectively regulate H at two specific walking speeds when using powered compared with passive-elastic prostheses.

Muscle contributions to frontal plane angular momentum during walking

“…Angular momentum has been investigated over a range of walking tasks such as steady-state walking (Herr and Popovic, 2008), walking at increasing speeds (Bennett et al, 2010), incline/decline walking (Silverman et al, 2012) and stair ascent/descent (Silverman et al, 2014). Angular momentum has also been analyzed during other movement tasks such as sit-to-stand (Reisman et al, 2002; Riley et al, 1997) and recovering from a trip (Pijnappels et al, 2004; Potocanac et al, 2014), and in different patient populations including elderly (Kaya et al, 1998; Pijnappels et al, 2005; Simoneau and Krebs, 2000), amputee (D’Andrea et al, 2014; Pickle et al, 2014; Sheehan et al, 2015; Silverman and Neptune, 2011) and post-stroke (Nott et al, 2014) subjects, and children with cerebral palsy (Bruijn et al, 2011). Collectively, these studies suggest that whole-body angular momentum is an important measure to quantify dynamic balance during human movement.…”

“…For example, previous work has shown that the range of frontal plane angular momentum is greater, and therefore less tightly regulated, in lower-limb amputees compared to non-amputees (D’Andrea et al, 2014; Pickle et al, 2014; Sheehan et al, 2015; Silverman and Neptune, 2011), which may explain why they are more susceptible to falling (Miller et al, 2001). Thus, understanding how individual muscles contribute to the regulation of frontal plane whole-body angular momentum has the potential to provide additional insight into the diagnosis and treatment of balance disorders.…”

Segmental contributions to sagittal-plane whole-body angular momentum when using powered compared to passive ankle-foot prostheses on ramps

“…H is tightly regulated during level-ground walking [1], but this regulation is affected by different walking tasks, such as sloped walking [2], and by neuromotor or musculoskeletal impairments, such as leg amputation [3]–[6], stroke [7], [8], and vestibular balance impairment [9]. However, current analyses of dynamic balance using H often incorporate two common practices.…”

Biomechanics of the human walk-to-run gait transition in persons with unilateral transtibial amputation

“…Amputated side peak anterior-posterior propulsive forces are consistently, significantly lower than able-bodied subjects and the intact side during walking at speeds ranging from 0.75–1.75m/s. (D’Andrea et al, 2014; Sanderson and Martin, 1997). Intact side peak anterior-posterior forces are not different from able-bodied subjects at speeds of 0.75, 1.50 or 1.75m/s (significantly higher than controls at 1.0 and 1.25m/s), however to our knowledge have never been investigated at walking speeds higher than 1.75m/s (D’Andrea et al, 2014).…”

“…(D’Andrea et al, 2014; Sanderson and Martin, 1997). Intact side peak anterior-posterior forces are not different from able-bodied subjects at speeds of 0.75, 1.50 or 1.75m/s (significantly higher than controls at 1.0 and 1.25m/s), however to our knowledge have never been investigated at walking speeds higher than 1.75m/s (D’Andrea et al, 2014). Furthermore, the walk-to-run gait transition has not previously been characterized in unilateral, transtibial amputees.…”