Proprioception in above-the-knee amputees with artificial limbs

Bodyweight distribution between limbs, muscle strength, and proprioception in traumatic transtibial amputees: a cross-sectional study

OBJECTIVES

To evaluate how transtibial amputation (TT) affects bodyweight distribution, voluntary knee joint position sense (JPS), and quadriceps (QUA) and hamstrings (HAM) strength in prosthetized patients.

METHODS

Only TT patients who had been prosthetized for more than one year were included, and an age-paired able-bodied group was used as control. The participants stood on force plates with their eyes open to measure bodyweight distribution between the limbs. Knee voluntary JPS was assessed by actively reproducing a set of given arbitrary joint angles using a video analysis approach, and QUA and HAM strength were assessed isometrically with a hand-held dynamometer.

RESULTS

Sixteen TT subjects (age: 39.4±4.8 years) and sixteen age-paired control subjects (age: 38.4±4.3 years) participated in the study. The amputees supported their bodyweight majorly on the sound limb (54.8±8.3%, p<0.001). The proprioceptive performance was similar between the amputated (absolute error (AE): 2.2±1.6°, variable error (VE): 1.9±1.6°, constant error (CE): -0.7±2.0°) and non-amputated limbs (AE: 2.6±0.9°, VE: 2.1±0.9°, CE: 0.02±2.3°), and was not different from that of control subjects (AE: 2.0±0.9°, VE: 1.4±0.4°, CE: -1.1±1.7°). There was a considerable weakness of the QUA and HAM in the amputated limb compared with the sound limb and control subjects (p<0.001 both).

CONCLUSIONS

The asymmetric bodyweight distribution in the transtibial amputees was not accompanied by a reduction in knee proprioception. There was significant weakness in the amputated limb, which could be a potential issue when designing rehabilitation programs.

A Wearable Vibrotactile Biofeedback System Targeting Gait Symmetry of Lower-limb Prosthetic Users

Lower limb prosthetic users exhibit gait deviations, which include asymmetrical stance time (ST), leading to secondary musculoskeletal problems. Biofeedback (BFB) systems have the potential to provide gait training to correct gait deviations. In this work, we describe a wearable BFB system that delivers vibrotactile feedback via two tactors (located at the anterior and posterior side of the residual limb of prosthetic users) to correct asymmetrical ST (%) using two strategies - single threshold feedback (SF) and bandwidth threshold feedback (BF). Validation of the system involved a sample of five lower limb amputees to examine the effectiveness of each strategy when compared to no feedback (NF) gait trials. Significant differences were found between no feedback and feedback trials. Although no significant differences were found between SF and BF, there are small but evident trends indicating that BF encourages ST (%) that is closest to the target with less error.

Biofeedback Systems for Gait Rehabilitation of Individuals with Lower-Limb Amputation: A Systematic Review

Individuals with lower-limb amputation often have gait deficits and diminished mobility function. Biofeedback systems have the potential to improve gait rehabilitation outcomes. Research on biofeedback has steadily increased in recent decades, representing the growing interest toward this topic. This systematic review highlights the methodological designs, main technical and clinical challenges, and evidence relating to the effectiveness of biofeedback systems for gait rehabilitation. This review provides insights for developing an effective, robust, and user-friendly wearable biofeedback system. The literature search was conducted on six databases and 31 full-text articles were included in this review. Most studies found biofeedback to be effective in improving gait. Biofeedback was most commonly concurrently provided and related to limb loading and symmetry ratios for stance or step time. Visual feedback was the most used modality, followed by auditory and haptic. Biofeedback must not be obtrusive and ideally provide a level of enjoyment to the user. Biofeedback appears to be most effective during the early stages of rehabilitation but presents some usability challenges when applied to the elderly. More research is needed on younger populations and higher amputation levels, understanding retention as well as the relationship between training intensity and performance.

Postural control skills, proprioception, and risk of fall in long-term survivor patients treated with knee rotationplasty

Knee A1 rotationplasty is a particular type of limb salvage surgery alternative to hip disarticulation and high transfemoral amputation for skeletally immature children with bone cancers in the distal femur. Notwithstanding optimal functional outcomes, long-term survivor patients often report frequent falls, and a sense of instability during gait, particularly on uneven terrain. This study aimed to assess the postural control, the proprioception, and the risk of fall in these patients, which have not been explored before. Eighteen long-term survivor patients participated in the study. The mean follow-up from surgery was 23 years, mean age 32 years. Patients were assessed using a specific instrumental device (Delos Postural Proprioceptive System) both for the static double-stance and the single-stance test in the open eyes and closed eyes conditions. The double-stance test showed postural instability values within the normal range for healthy individuals, whereas in the single-stance test stability index, when assessed in the average of both lower limbs, values were lower than the literature findings for older individuals. However, when separating the operated from the nonoperated limb performance, standing on the operated limb was very unstable, with a low stability index and a low degree of autonomy, indicating a certain risk of falling, whereas standing on the nonoperated limb had a performance close to normal or even superior. In conclusion, knee rotationplasty patients had very good postural control when standing on both limbs, whereas single stance on the operated limb was compromised, with particular involvement of the proprioceptive component. This may determine a higher risk of falling than their normal-age counterparts and rehabilitation intervention for prevention is indicated.