Predictive Measurement for Windlass Change in Length and Selected Treatment Outcomes in Chronic Plantar Fasciitis

Summary

This protocol presents an objective, easy, and economical method to measure the change in length of the windlass in plantar fasciitis and assess the effectiveness of a selected treatment procedure employed in this study over a one-month period.

Abstract

Approximately 10% of patients with plantar fasciitis experience persistent and often severe symptoms, though little is known about its etiology. The goal of this study was to employ an objective, simple, and economical approach to measure the change in length of the windlass and assess the efficiency of a specified therapy protocol applied in this study over a one-month period. Age, weight, normal foot type, and gender were employed as matching factors in a matched design. Fifty individuals diagnosed with unilateral plantar fasciitis and an equal number of healthy volunteers all fulfilled the inclusion criteria and took part in this research. Pain assessment utilized a visual analogue scale and the pain subscale of the foot function index, while a valid goniometric method was employed to evaluate weight-bearing windlass, dorsiflexion and plantar flexion ranges of motion. Additionally, foot plantar pressure (both static and dynamic measures) and tape measurement of windlass change in length were assessed. The assessment was completed by all patients before and after their treatment program. Normal subjects were evaluated for control. Treatment methods encompassed ultrasonic therapy, application of an electrical heating pad, utilization of a night splint, engagement in stretching activities for the plantar aponeurosis and Achilles tendon, as well as both extrinsic and intrinsic strengthening exercises. After one month, the patients were reassessed and compared to control volunteers. In those suffering from plantar fasciitis, a substantial link was found between clinical measurements (tape measurement, windlass range of motion) and foot plantar pressure, indicating improvement. The chosen treatment protocol was effective in 96% of patients. For windlass length change, the measurement technique was found to be valid and objective. The chosen therapy procedure was successful in treating persistent plantar fasciitis in patients.

Introduction

Plantar fasciitis is characterized as an overuse syndrome involving localized inflammation of the plantar aponeurosis at its anatomical origin on the medial tubercle of the calcaneus¹. Although the exact cause is unknown, the prevailing opinion suggests that it arises from repeated partial tears and persistent inflammation within the plantar aponeurosis at its attachment point on the medial tubercle of the calcaneus². Plantar fasciitis has been theorized to result from weak plantar intrinsic or extrinsic muscles, which fail to provide adequate dynamic truss support for the longitudinal arch, thereby transferring additional tensile stress to the plantar aponeurosis. This excess tensile stress may lead to fatigue failure, triggering an inflammatory response and the formation of scar tissue, further shortening the tissue³.

While there is no gold standard diagnostic criterion for plantar fasciitis, the clinical presentation is widely recognized. Symptoms include pain and palpable soreness around the medial tubercle of the calcaneus, increased pain during the first few steps in the morning, and exacerbated pain with sustained weight-bearing. Despite extensive research efforts, foot surgeons continue to debate the cause, etiology, and optimal treatment strategy for plantar fasciitis⁴.

According to the windlass model, increased stresses on the first metatarsal head and hallux result in heightened tension in the medial slip of the plantar aponeurosis, offering a plausible explanation for the pain associated with plantar fasciitis. Pain may manifest in the aponeurosis or at its attachment to the bone when the aponeurosis is strained⁵. The windlass test stands out as the sole specialized diagnostic tool for detecting inflammation of the plantar fascia⁶. Using lateral radiography images of the foot in the loading position, the length of the plantar aponeurosis has been calculated as the distance between two bony markers: the calcaneal medial tuberosity and the base of the first metatarsal head⁷. The force generated by the contraction of the Achilles tendon serves as a reliable predictor of plantar aponeurosis tension^8,9.

Various conservative treatments, such as physical therapies, manual therapy, stretching exercises, and orthotic equipment, have been recommended for plantar fasciitis. Options also include taping, shoe adjustments, nonsteroidal anti-inflammatory drugs, cortisone injections, or combinations of these treatments¹⁰.

While there is no singular definitive treatment for plantar fasciitis, the condition can be managed in three stages: addressing the inflammatory lesion at the enthesis, correcting precipitating factors, and implementing a progressive rehabilitation program leading to a return to activity¹¹.

The objective of this study was to employ an objective, simple, and economical approach to measure the change in length of the windlass and assess the efficiency of a specified therapy protocol over a one-month period. The study investigated the response of patients with chronic plantar fasciitis to a treatment protocol involving structure-specific plantar aponeurosis stretching, Achilles tendon stretching, extrinsic and intrinsic foot muscle strengthening, a night splint, and the use of pulsed ultrasonic waves and an electrical heating pad. This regimen was selected based on clinical experience, with a significant percentage of patients reporting symptom relief. The hypothesis was that there is a correlation between clinical outcome measurements (tape and goniometer) and foot plantar pressure values, and that patients with chronic plantar fasciitis managed with this specific treatment protocol show improved outcomes after four weeks compared to measurements taken prior to treatment and those of normal subjects.

Participants
The study comprised two groups: one group included fifty patients diagnosed with unilateral plantar fasciitis, and another group consisted of fifty normal subjects. All patients were referred to the outpatient physical therapy clinic at Kasr Al-Aini Hospital by orthopaedic surgeons. Every patient experienced pain in the region where the plantar aponeurosis attaches to the medial tubercle of the calcaneus. In every instance, pain manifested when patients took their initial steps in the morning and intensified with weight-bearing activities throughout the day. Exclusion criteria encompassed patients diagnosed with spinal disorders, tarsal tunnel syndrome, cortisone injections in the heel area, or any pathology like hammer toe or hallux valgus, as well as anatomical abnormalities like pes cavus or pes planus that may predispose to the development of this condition, and the presence of a calcaneal spur. Patients with bilateral plantar fasciitis were also excluded. The mean age of the patients was 39.18 ± 5.43 years, with a gender distribution of 35 women and 15 men. The mean weight was 88.3 ± 11.46 kg, and the mean body mass index was 24.64 ± 32.76 kg/m². The mean duration between the onset of pain and admission to the study was 9 months.

This study was designed with a 1:1 matching, assigning one control for each patient, as 40% of individuals with unilateral plantar fasciitis develop symptoms in the contralateral limb¹². The control group was selected to compare the patients' measurements after treatment with those of normal subjects. Matching criteria included age, gender, weight, and body mass index. The control group comprised 50 subjects who reported never being diagnosed with plantar fasciitis and had no lower extremity injuries in the previous year or any abnormalities like pes cavus or pes planus. The control group was recruited from Kasr Al-Aini Hospital employment, with a mean age of 37.38 ± 38.6 years, a gender distribution of 36 women and 14 men, a mean weight of 88.94 ± 8.1 kg, and a mean body mass index of 24.5 ± 31.82 kg/m².

Protocol

All procedures conducted in this study adhered to the pertinent guidelines and regulations of Helsinki 2013. Ethical approval was obtained from Kasr Al-Aini Hospital's ethical committee. The informed consent form was prepared in accordance with the standards set by the Ethics Committee of the hospital and obtained from the patients by the hospital's secretary, who played no role in this trial. Eligible patients were thoroughly informed about the interventions before signing the consent form. All subjects provided written informed consent prior to participating in the study, in accordance with Cairo University's ethics policy.

1. Patient preparation

1. Gather data variables for each subject, identified most frequently in the literature as potential risk factors for plantar fasciitis according to Riddle et al.¹³.
2. Calculate body mass index (BMI) using the formula BMI = weight (kg) / (height (m))².
3. Ask the patients to complete the foot function index pain subscale (FFI) questionnaire¹⁴.
   NOTE: The FFI pain subscale consists of 9 questions designed to assess the impact of foot pathology on function, specifically focusing on pain, for all patients.
4. Utilize a visual analog scale (VAS) for pain measurement¹⁵.

2. Measurement of windlass change in length

1. Visually assess patients and normal subjects (control group) for neutral foot type according to Dahle et al.¹⁶ classification.
2. Measure the windlass test range of motion for both patients and the control group from weight-bearing positions⁶.
   1. Measure the windlass change in length from the weight-bearing position for both groups using tape measurement, as suggested in this design. The reference points used for this length were the medial tubercle of the calcaneus (at the origin of the plantar aponeurosis) and the plantar plates of the 1^st metatarsophalangeal joint.
   2. Mark both sites with a skin marker and affix the tape to the medial tubercle of the calcaneus while the participant is in a sitting position.
   3. Instruct the patient to stand and extend the tape to the second point to minimize skin motion. The distance between the two points represents the windlass change in length, measured in centimeters.
   4. Conduct three consecutive measurements for tape measurement for each participant (patient and control), then calculate the mean value of the three measurements (Figure 1).
3. Measure the range of motion of the windlass mechanism, ankle dorsiflexion, and plantar flexion for both groups using a goniometer (see Table of Materials).
4. Evaluate foot plantar pressure recorded for patients and the control group under both static and dynamic conditions. Record subject details such as name, age, weight, and height. Record peak pressure values (kg/cm²) at eight regions: medial calcaneus, lateral calcaneus, first metatarsal, second metatarsal, third metatarsal, fourth metatarsal, fifth metatarsal, and big toe.
   NOTE: Calibration involves converting the raw digital output of the sensor to actual pressure (kg/cm²). Calibration was performed by having the subjects stand on the sensor with both feet briefly. Calibration was conducted before each new patient session, after the treatment protocol session, and for the control group as well.
   1. Perform static measurement^17,18.
      1. During static measurement, instruct the subjects to stand on the affected foot and focus on a fixed point on the wall, positioned 2 m away.
         NOTE: This assessment was conducted for both patients and normal subjects (control group). Three trials were recorded to ensure reliable pressure data.
   2. Conduct dynamic measurement.
      1. Instruct patients to walk barefoot at their natural speed and stop on the active surface of the platform with the affected foot only, without looking down at the platform across the plantar pressure platform embedded in a 100 cm walkway.
         NOTE: Highlight the importance of executing a regular step within the complete gait cycle, ensuring the maintenance of a normal walking speed and step length, and ensuring that the entire foot contacts the platform. After conducting several trials, designate a starting point that accommodates a three-step approach. Specifically, position the foot opposite to the one under examination to initiate the first step, with the test foot making contact with the platform on the second step from the established starting position.Use a two-step gait initiation protocol to collect foot pressure data^19,20.
      2. Record three trials for each subject, a number determined to ensure reliable pressure data.

3. Analysis of plantar pressure data

1. After data collection, determine peak pressure (kg/cm²) under eight regions of the foot^19,20: medial calcaneus, lateral calcaneus, 1^st metatarsal, 2^nd metatarsal, 3^rd metatarsal, 4th metatarsal, 5^th metatarsal, and big toe (Figure 2) using commercially available software (see Table of Materials).
   NOTE: Use the sum of the three trials under each point to calculate the mean peak pressure for each of the eight points.
2. Conduct post-treatment measurements at the same points and in the same manner for measurement and analysis of pressure distribution.
3. Treat patients with a clinical protocol of foot strengthening exercises.
   NOTE: Administer the Patient group a modified treatment protocol three times per week for four weeks, including the following:
   1. Apply pulsed ultrasound along the length of the plantar aponeurosis from the origin to the insertion on the medial compartment for 3 min at an intensity of 0.5 W/cm²/MHz.
   2. Apply a low-level electrical heating pad for 20 min under the entire foot.
   3. Instruct patients to perform manual stretching exercises for the Achilles tendon muscles from a non-weight-bearing position, weight-bearing self-stretching of the Achilles tendon muscles from a standing position using a slant board, and stretching exercises for the plantar aponeurosis.
   4. Instruct patients to perform manual strengthening exercises for the dorsiflexor and plantar flexor muscles, as well as strengthening exercises for intrinsic foot muscles using a rolled towel placed under the plantar aspect of the toes while seated, progressing to picking up the towel with the toes.
   5. Advise each patient to wear a night splint while sleeping and to remove the splint immediately upon waking in the morning, providing instructions on how to wear it.
4. Analyze the outcome measures, including pain, range of motion of dorsiflexion and plantar flexion, range of motion of the windlass mechanism, windlass change in length, and static and dynamic plantar pressure^19,20.

Results

The Statistical Package for the Social Sciences (SPSS, see Table of Materials) was employed for all statistical procedures, as all outcome variables exhibited a normal distribution. Means, standard deviations, and standard errors were used as summary statistics. Analyses were conducted to examine differences in the general characteristics of participants (patients and control groups), including age, gender, weight, and body mass index. Differences in each dependent variable of interest (pain, windlass ch...

Discussion

The outcomes for individuals with persistent plantar fasciitis are generally positive, with conservative therapy showing success rates ranging from 46% to 100%¹. Prolonged issues may lead to additional treatments, including surgery, but the recovery time is often lengthy and may not allow for full function²¹. Therefore, optimizing nonoperative therapy is crucial before considering surgical options. Despite its chronic nature, most nonoperative therapies for plantar fasciiti...

Materials

Name	Company	Catalog Number	Comments
Electrical hot pad	koolpak.co.uk		Treatment by Heat; Reusable Hot & Cold Pack With Elasticated Strap & Physio Hot & Cold Pack
Goniometer	ASA TECHMED	ASATECHMED	Measure ROM; 6 Pcs 360° 12, 8 and 6 Inch Medical Spinal Goniometer Angle Protractor Angle Ruler
Pulsed ultrasonic	TAGWW		Ultrasonic-Personal-Massager-Spasmodic-Relaxation
Slant board	StrongTek		StrongTek Professional Wooden Slant Board, Adjustable Incline Board and Calf Stretcher, Stretch Board - Extra Side-Handle Design for Portability
SPSS software	IBM		https://www.ibm.com/products/spss-statistics?utm_content =SRCWW&p1=Search&p4 =43700078595923635&p5 =e&gclid=Cj0KCQiA2KitBh CIARIsAPPMEhJOBrK6zP 26critWGEWE_6CVZnZeG tXQmgdUh9Na0LgSspKzB Zg7vAaAvdIEALw_wcB&g clsrc=aw.ds
Tekscan software		version 5.20	https://www.tekscan.com/support/drivers