iWALK3.0 – Clinical Research

Unlike crutches and knee scooters, the iWALK is a hand free mobility device. Thus, activities of daily living (ADLs and IADLs) that are impossible to do with crutches and knee scooters such as shopping, working, cooking, child care, etc. are possible with the iWALK. A randomized control trial with 80 patients with both upper and lower limb injuries showed that they were able to complete activities around the house using the iWALK [4] and patients had a more positive attitude to life due to the improved independence with the iWALK [5]. This could be just one of the reasons why the iWALK has a higher preference rate than crutches [1].

Research proves that the iWALK provides statistically significant increases in muscle activity for the hip, quadriceps and calf muscles in the non-weight bearing leg with muscle activity patterns consistent with normal unassisted ambulation in terms of both intensity and activation times [6, 7]. On the other hand, crutches and knee scooters lead to statistically significant reductions in muscle activity in the non-weight bearing leg compared to normal unassisted ambulation [6-9]. The heightened level of muscle engagement in the non-weight bearing leg using the iWALK compared to crutches will lead to decreased atrophy, increased blood flow and enhanced healing [6].

The heightened recruitment of the muscles in the non-weight bearing leg when using the iWALK compared to crutches is expected to decrease the level of disuse muscle atrophy [6], based on associated research that shows the degree a muscle will atrophy is dependent on the activity of the muscle [8, 10, 11]. It is widely accepted that crutches lead to significant muscle atrophy with reductions in muscle size and strength as well as structural changes in muscle fibers from prior studies [9, 12-17].

Using the iWALK crutch leads to increased blood flow in the non-weight bearing limb. Research has shown that an iWALK provides the greatest muscle activity for the calf muscles compared to crutches and knee scooters [6, 7] and associated research has shown that the calf muscles play a vital role in blood flow [18, 19]. This is further supported by prior studies that have shown decreases in blood flow of the lower extremities for both crutches [20] and knee scooters [21]. When poor blood flow continues, it can cause blood clots in the lower extremities [18, 22] and negatively impact bone remodeling [23].

Low rates of blood flow in the lower extremities increases the risk of developing blood clots [24]. Using an iWALK can reduce the risk of developing blood clots, as demonstrated in associated research that shows muscle contractions in the calf muscles contribute to increasing blood flow [18, 19] and research that shows that an iWALK increases muscle activity for the calf muscles [6, 7]. Crutches have been shown to cause blood clots in prior research [25], while knee scooter have been associated with lower blood flow that could potentially increase the risk of developing blood clots [21]. Blood clots can lead to substantial impairment and direct healthcare expenditures [26, 27].

A randomized control trial conducted using 80 patients showed that patients were discharged significantly faster after using an iWALK compared with using other mobility devices [4]. The reduction in muscle atrophy and improvement in blood flow when using an iWALK will impact the total recovery time for lower limb injuries with quicker rehabilitation, enhanced healing and less cases of blood clots [6]. The nonexistence of secondary injuries associated to crutches when using an iWALK will also contribute to reducing the recovery times of lower limb injuries.

Crutches lead to seven-fold increase in the force that runs through the axilla [28]. This increased force at the axilla has been shown to lead to secondary injuries such as axillary artery thrombosis [29] and crutch palsy [30]. Other complications as a result of crutch use are carpal tunnel syndrome [31] and shoulder joint degeneration [32]. Secondary injuries may also occur with knee scooters due to the increased risk of falling [33, 34]. Because there is no loading of the hands and upper extremity when using an iWALK, secondary injuries are nonexistent with the iWALK.

A randomized control trial conducted using 80 patients showed that patients were discharged significantly faster after using an iWALK compared with using other mobility devices [4]. The reduction in muscle atrophy and improvement in blood flow when using an iWALK will impact the total recovery time for lower limb injuries with quicker rehabilitation, enhanced healing and less cases of blood clots [6]. The nonexistence of secondary injuries associated to crutches when using an iWALK will also contribute to reducing the recovery times of lower limb injuries.

A randomized control trial conducted using 80 patients showed that patients were discharged significantly faster after using an iWALK compared with using other mobility devices [4]. The reduction in muscle atrophy and improvement in blood flow when using an iWALK will impact the total recovery time for lower limb injuries with quicker rehabilitation, enhanced healing and less cases of blood clots [6]. The nonexistence of secondary injuries associated to crutches when using an iWALK will also contribute to reducing the recovery times of lower limb injuries.

The iWALK could improve patient compliance to non-weight bearing restrictions, due to prior research that shows that patients prefer an iWALK over crutches and the important role patient preference plays on patient compliance [1]. In addition to this, because patients are able to function independently using an iWALK with the ability to do activities of daily living [4], the iWALK will lead to better compliance for patients with lower limb injuries who have been known to be noncompliant with prescribed weight bearing restrictions in prior studies [2, 3, 35]. Lack of compliance may lead to complications such as wound breakdown, loss of fracture fixation or hardware failure [3].

Increased physiological demand has been shown to be an important factor in discontinuance and noncompliance to weight bearing restrictions with the use of assistive devices [36]. Therefore, mobility devices designed to assist ambulation should keep energy expenditure to a minimum while still allowing normal walking speeds. Prior research shows that the physiological demand and exertion are lowest for the iWALK compared to crutches and knee scooters, while all three mobility devices have similar self-selected walking speeds [1, 37]. This is further supported in prior studies where crutches have been shown to lead to significantly higher energy costs compared to normal unassisted ambulation [38-44].

1. Martin, K.D., et al., Patient Preference and Physical Demand for Hands-Free Single Crutch vs Standard Axillary Crutches in Foot and Ankle Patients. Foot & ankle international, 2019. 40(10): p. 1203-1208.
2. Chiodo, C.P., et al., Patient compliance with postoperative lower-extremity non-weight-bearing restrictions. JBJS, 2016. 98(18): p. 1563-1567.
3. Gershkovich, G., et al., Weight bearing compliance after foot and ankle surgery. Foot & Ankle Orthopaedics, 2016. 1(1): p. 2473011416S00089.
4. Rambani, R., M.S. Shahid, and S. Goyal, The use of a hands-free crutch in patients with musculoskeletal injuries: randomized control trial. International Journal of Rehabilitation Research, 2007. 30(4): p. 357-359.
5. Barth, U., et al., Alternative Mobilization by Means of a Novel Orthesis in Patients after Amputation. Zeitschrift für Orthopädie und Unfallchirurgie, 2019. 158(01): p. 75-80.
6. Dewar, C. and K.D. Martin, Comparison of Lower Extremity EMG Muscle Testing With Hands-Free Single Crutch vs Standard Axillary Crutches. Foot & Ankle Orthopaedics, 2020. 5(3): p. 2473011420939875.
7. Sanders, M., et al., The influence of ambulatory aid on lower-extremity muscle activation during gait. Journal of sport rehabilitation, 2018. 27(3): p. 230-236.
8. Clark, B.C., et al., Leg muscle activity during walking with assistive devices at varying levels of weight bearing. Archives of physical medicine and rehabilitation, 2004. 85(9): p. 1555-1560.
9. Seynnes, O.R., et al., Early structural adaptations to unloading in the human calf muscles. Acta physiologica, 2008. 193(3): p. 265-274.
10. Antonutto, G., et al., Effects of microgravity on maximal power of lower limbs during very short efforts in humans. Journal of Applied Physiology, 1999. 86(1): p. 85-92.
11. Clark, B.C., In vivo alterations in skeletal muscle form and function after disuse atrophy. Medicine and science in sports and exercise, 2009. 41(10): p. 1869-1875.
12. Berg, H., et al., Effects of lower limb unloading on skeletal muscle mass and function in humans. Journal of Applied Physiology, 1991. 70(4): p. 1882-1885.
13. Hather, B.M., et al., Skeletal muscle responses to lower limb suspension in humans. Journal of Applied Physiology, 1992. 72(4): p. 1493-1498.
14. Dudley, G.A., et al., Adaptations to unilateral lower limb suspension in humans. Aviation, space, and environmental medicine, 1992. 63(8): p. 678-683.
15. Ploutz-Snyder, L.L., et al., Effect of unweighting on skeletal muscle use during exercise. Journal of Applied Physiology, 1995. 79(1): p. 168-175.
16. Campbell, E.-L., et al., Skeletal muscle adaptations to physical inactivity and subsequent retraining in young men. Biogerontology, 2013. 14(3): p. 247-259.
17. Adams, G., B. Hather, and G. Dudley, Effect of short-term unweighting on human skeletal muscle strength and size. Aviation, space, and environmental medicine, 1994. 65(12): p. 1116-1121.
18. Faghri, P.D., et al., Electrical stimulation-induced contraction to reduce blood stasis during arthroplasty. IEEE transactions on rehabilitation engineering, 1997. 5(1): p. 62-69.
19. Faghri, P.D., J.J. Votto, and C.F. Hovorka, Venous hemodynamics of the lower extremities in response to electrical stimulation. Archives of physical medicine and rehabilitation, 1998. 79(7): p. 842-848.
20. Bleeker, M.W., et al., Vascular adaptation to 4 wk of deconditioning by unilateral lower limb suspension. American Journal of Physiology-Heart and Circulatory Physiology, 2005. 288(4): p. H1747-H1755.
21. Ciufo, D.J., M.R. Anderson, and J.F. Baumhauer, Impact of Knee Scooter Flexion Position on Venous Flow Rate. Foot & ankle international, 2019. 40(1): p. 80-84.
22. McLachlin, A.D., et al., Venous stasis in the lower extremities. Annals of surgery, 1960. 152(4): p. 678.
23. Bergula, A., W. Huang, and J. Frangos, Femoral vein ligation increases bone mass in the hindlimb suspended rat. Bone, 1999. 24(3): p. 171-177.
24. Stick, C., H. Grau, and E. Witzleb, On the edema-preventing effect of the calf muscle pump. European journal of applied physiology and occupational physiology, 1989. 59(1-2): p. 39-47.
25. Bleeker, M.W., et al., Unilateral lower limb suspension can cause deep venous thrombosis. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2004. 286(6): p. R1176-R1177.
26. Bergqvist, D., et al., Cost of long-term complications of deep venous thrombosis of the lower extremities: an analysis of a defined patient population in Sweden. Annals of internal medicine, 1997. 126(6): p. 454-457.
27. Ruckley, C., Socioeconomic impact of chronic venous insufficiency and leg ulcers. Angiology, 1997. 48(1): p. 67-69.
28. Wagstaff, P., The energetics of walking using axillary crutches and the prototype of a new design termed the dublin crutch. Physiotherapy, 1984. 70(11): p. 422-424.
29. Tripp, H.F. and J.W. Cook, Axillary artery aneurysms. Military medicine, 1998. 163(9): p. 653-655.
30. Raikin, S. and M.I. Froimson, Bilateral brachial plexus compressive neuropathy (crutch palsy). Journal of orthopaedic trauma, 1997. 11(2): p. 136-138.
31. Gellman, H., I. Sib, and R.L. Waters, Late complications of the weight-bearing upper extremity in the paraplegic patient. Clinical Orthopaedics and Related Research®, 1988. 233: p. 132-135.
32. Shabas, D. and M. Scheiber, Suprascapular neuropathy related to the use of crutches. American journal of physical medicine, 1986. 65(6): p. 298-300.
33. Yeoh, J., et al., Post-Operative Use of the Knee Walker After Foot and Ankle Surgery, A Retrospective Study. Foot & Ankle Orthopaedics, 2017. 2(3): p. 2473011417S000419.
34. Rahman, R., B.A. Shannon, and J.R. Ficke, Knee Scooter–Related Injuries: A Survey of Foot and Ankle Orthopedic Surgeons. Foot & Ankle Orthopaedics, 2020. 5(1): p. 2473011420914561.
35. Kubiak, E.N., et al., Early weight bearing after lower extremity fractures in adults. JAAOS-Journal of the American Academy of Orthopaedic Surgeons, 2013. 21(12): p. 727-738.
36. Bateni, H. and B.E. Maki, Assistive devices for balance and mobility: benefits, demands, and adverse consequences. Archives of physical medicine and rehabilitation, 2005. 86(1): p. 134-145.
37. Kocher, B.K., et al., Comparative study of assisted ambulation and perceived exertion with the wheeled knee walker and axillary crutches in healthy subjects. Foot & ankle international, 2016. 37(11): p. 1232-1237.
38. Mcbeath, A.A., M. Bahrke, and B. Balke, Efficiency of assisted ambulation determined by oxygen consumption measurement. JBJS, 1974. 56(5): p. 994-1000.
39. Sankarankutty, M., J. Stallard, and G. Rose, The relative efficiency of ‘swing through’gait on axillary, elbow and Canadian crutches compared to normal walking. Journal of biomedical engineering, 1979. 1(1): p. 55-57.
40. Dounis, E., et al., A comparison of efficiency of three types of crutches using oxygen consumption. Rheumatology, 1980. 19(4): p. 252-255.
41. Hinton, C.A. and K.E. Cullen, Energy expenditure during ambulation with ortho crutches and axillary crutches. Physical therapy, 1982. 62(6): p. 813-819.
42. Bhambani, Y. and H. Clarkson, Acute physiologic and perceptual responses during three modes of ambulation: walking, axillary crutch walking, and running. Archives of physical medicine and rehabilitation, 1989. 70(6): p. 445-450.
43. Nielsen, D.H., et al., Energy cost, exercise intensity, and gait efficiency of standard versus rocker-bottom axillary crutch walking. Physical therapy, 1990. 70(8): p. 487-493.
44. Thys, H., P. Willems, and P. Saels, Energy cost, mechanical work and muscular efficiency in swing-through gait with elbow crutches. Journal of biomechanics, 1996. 29(11): p. 1473-1482.