Customized Foot Orthoses With Orthotic Wedges for Plantar Heel Pain

Pain intensity during the last week will be assessed using the visual analog scale (VAS) which is the high-reliability measurement (ICC = 0.88). The highest pain level is 10 and the lowest pain level is 0. In addition, the foot function will be assessed by the 23-item foot function index (FFI). The present study will use the Thai version of FFI that has been translated forward and backward from the English version. The previous study showed high internal consistency (Cronbach alpha = 0.98) and high test-retest reliability (ICC = 0.86). It is appropriate to use among patients with PHP.

Plantar fascia thickness will be assessed by a portable digital Ultrasound (US) diagnosis imaging system, D-6600 (Mindray, China) with a 10 MHz wideband linear array probe. Intra-rater reliability from the assessment showed an ICC(3,1) of 0.97. To evaluate the plantar fascia thickness, scan depth will be set at 4 cm. The measurement protocol will follow the recommendation from the European Society of Musculoskeletal Radiology.

A gait analysis system (Zebris FDM, Isny, Germany) will be used to collect the gait parameters at a sampling frequency of 100 Hz over a 3-m force distribution platform. The participants will be asked to walk with a self-selected speed to the other end of the platform for 3 trials. Data will be averaged and used in further analysis. The gait parameters include stance time (s), double support time (%), stride time (s), step length (cm), step width (cm), stride length (cm), cadence (steps/min), and walking velocity (km/h).

A gait analysis system (Zebris FDM, Isny, Germany) will be used to collect the balance parameters at a sampling frequency of 100 Hz over a 3-m pressure distribution platform. The participants will be asked to stand with both legs on the firm and foam surface in two conditions i.e. eye closed and eye open, for 20 s in each condition. And then, they will be asked to walk at a self-selected speed to the other end of the platform. Each condition will be tested for 3 trials and averaged data will be used in further analysis. The following parameters from the platform will be acquired:

• Sway path length of center of pressure (COP) (mm) is the total length of the path marked by COP
• Average velocity of COP (mm/s) is the speed of changes in the COP location
• COP area (mm2) is the size of the area marked by COP

LBP during the last week will be assessed using the Thai version of the Roland-Morris disability questionnaire. The previous study showed high internal consistency (Cronbach alpha = 0.83), which is a reliable tool to assess functional disability of LBP in Thai persons. In addition, hip pain during the last week will be assessed using the Thai version of the hip disability and osteoarthritis outcome (HOOS). The previous study showed high internal consistency for the pain subscale (Cronbach alpha = 0.89) and high test-retest reliability (ICC = 0.94). Regarding the assessment of knee pain during last week, the Thai version of the knee osteoarthritis outcome score (KOOS) will be used. The previous study showed high internal consistency (Cronbach alpha = 0.90) and moderate test-retest reliability for the pain subscale (ICC = 0.78).

TrA thickness will be assessed by a portable digital Ultrasound (US) diagnosis imaging system, D-6600 (Mindray, China) with a 10 MHz wideband linear array probe. The measurement protocol will follow the recommendation from the European Society of Musculoskeletal Radiology. TrA thickness will be assessed for three trials and the averaged data will be used for the comparison in data analysis.

A self-reported questionnaire will be divided into 4 parts, including individual information (i.e. sex, age, gender, dominant side, body mass index, job, average time during standing and walking), general health information (i.e. characteristics of heel pain, history of injury and fracture at the lower extremity, falling history, types of footwear), foot pain and function, low back pain and lower-extremity pain.

Physical characteristics of the participants will be assessed by the 1st physical therapist, including measurements of standing posture, leg length, quadriceps angle, tibiofemoral angle, knee recurvatum, dorsiflexion lunge test, navicular drop test, first metatarsophalangeal joint angle and posture, foot posture during standing and prone lying, neural tension test, lateral step down test, and star excursion balance test. Intra-rater reliability from data of each physical assessment among 10 persons showed the Intraclass Correlation Coefficients ICC(3,1) values ranging from 0.69 to 0.98.