Authors (including presenting author) :
Leung HS(1)(2), Yung PSH(2), Mok KM(2), Chan ZYS(3), Cheung RTH(2)(3)
Affiliation :
(1) Prosthetic & Orthotic Department, Pamela Youde Nethersole Eastern Hospital, (2) Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, (3) Gait & Motion Analysis Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University
Introduction :
Foot orthoses are commonly prescribed to manage runners with plantar fasciitis, which has been associated with biomechanical risk factors, such as excessive foot pronation and high vertical loading rates. Traditional plaster-molded method is currently used in clinical practice while 3D printing technology is a novel method for foot orthoses fabrication. However, the functional difference between traditional plaster-molded orthoses (TPM) and 3D printed (3DP) orthoses on the running biomechanics remains unknown.
Objectives :
This study evaluated the running biomechanics with TPM and 3DP orthoses in runners with risk factors of plantar fasciitis.
Methodology :
15 symptom-free recreational female runners with excessive foot pronation and rearfoot strike landing pattern were recruited. They ran on an instrumented treadmill in three conditions: (1) TPM orthoses; (2) 3DP orthoses and (3) without orthoses (Ctrl) in a randomized test sequence. Rearfoot angle, vertical loading rates and perceived comfort in each condition were measured and analyzed.
Result & Outcome :
Kinematically, runners with TPM (p=0.001, Cohen’s d=0.382) or 3DP orthoses (p=0.002, Cohen’s d=0.240) exhibited lower rearfoot angle than Ctrl. When comparing between the two types of orthoses, the rearfoot angle was slightly higher in the 3DP orthoses (p=0.043, Cohen’s d=0.149). Kinetically, no significant differences in vertical loading rates were found among the three conditions (F=0.032-0.178, p=0.838-0.969). Regarding subjective comfort, runners experienced better “medial-lateral control” and “heel cushioning” with TPM orthoses (p< 0.001, Cohen’s d=1.741; p=0.001, Cohen’s d=1.819 respectively) and 3DP orthoses (p=0.003, Cohen’s d=1.340; p=0.002, Cohen’s d=1.061 respectively). Better self-perceived “arch height” (p=0.011, Cohen’s d=1.358) was reported when using TPM orthoses, while the difference between 3DP orthoses and the control condition was marginally insignificant (p=0.056, Cohen’s d=0.937).
Both TPM and 3DP orthoses are able to control foot pronation and enhance subjective perception of “medial-lateral control” and “heel cushioning” in runners, but they do not reduce vertical loading rates. There are subtle differences in the biomechanical effects between the two types of orthoses.
3D printing technology may be used for foot orthoses fabrication to control the biomechanical risk factors related to plantar fasciitis in runners.
