Comparison of the effects of low level laser and insoles on pain,functioning,and muscle strength in subjects with stage 2 posterior tibial tendon dysfunction: A randomized study

Abstract

BACKGROUND:

Low level laser therapy (LLLT) is known to be effective in tendinopathies. No study yet investigated the effect of LLLT on posterior tibial tendon dysfunction (PTTD) in comparison to orthotic treatment.

OBJECTIVE:

The aim was to compare the effects of LLLT and insole application on pain, function and muscle strength in subjects with stage 2 PTTD.

METHODS:

Fifty-two subjects with stage 2 PTTD were randomly assigned to the LLLT and insole groups. The foot pain, function and strength of invertor and evertor muscles of the subjects was evaluated before and after treatment, and after 9 months.

RESULTS:

Significant improvement was observed in the foot function and pain ( $p<$ 0.05) in both groups after treatment, but in the 9-month follow-up, the insole group had better values. The increase in 180 ${}^{\circ}$ .sec ${}^{-1}$ concentric invertor muscle strength was found significant after the treatment and in month-9 as compared to the initial values ( $p<$ 0.05).

CONCLUSIONS:

Both treatments are effective in reducing treating foot pain, as well as improving the function in subjects with stage 2 PTTD. However, at the end of the 9-month follow-up, it was seen that insoles were more effective. Neither method had a clinically important effect on muscle strength.

Keywords

Low level laser therapy foot orthoses posterior tibial tendon dysfunction

1. Introduction

Posterior tibial tendon dysfunction (PTTD) is defined as progressive loss of strength due to the tendinopathy of the posterior tendon of the tibialis as a result of increased mechanical loading, vascular, acute trauma and collagen anomaly [1, 2]. Tendinosis of the posterior tibial muscle tendon is associated with subsequent over pronation of the subtalar joint, hindfoot valgus, medial longitudinal arch collapse and forefoot abduction [3]. PTTD is known as the most important cause of adult acquired pes planus and its important risk factors include obesity, diabetes, hypertension, and use of steroids [4].

According to the most frequently used PTTD classification, the disease has 4 stages. In addition, Bluman at al. described 14 subgroups of the pathology by taking into account the ankle and hindfoot valgus, forefoot supination, forefoot abduction, and medial column instability, and provided potential treatments for each stages [5]. While stages 3–4 commonly require surgical correction of the rigid deformity, conservative treatment options are tried for stages 1 and 2 and also for some subjects with higher stages that surgery is not allowed [5]. Positive effects of the conservative treatment with anti-inflammatory drugs, cold application, orthotics, shoe modification, exercise, and therapeutic ultrasound have been shown previously [2]. Orthotics, which are used to control subtalar pronation and mechanically support the posterior muscle of the tibialis include insoles, UCBL, or ankle-foot orthosis (AFO). The right one is commonly chosen according to the severity of symptoms [6, 7]. Studies investigating the efficacy or orthotics generally focus on cases at stages 2 and 3, and show that foot functions could be improved through taking the symptoms under control in the short or long term [8, 9]. In the studies investigating the effect of orthotics in the conservative management of PTTD, the orthoses used vary according to the stage of the disease, such as insoles, UCBL, Arizona or hinged AFO [8, 10, 11]. In these researches authors reported a success rate ranging between 50–69.7% in 12 months to 10 years follow-up.

There is no consensus in the literature on what orthotics treatment should be used in which PTTD stage. In some studies, the UCBL orthosis is generally preferred for stage 2 cases, but there are also studies followed up with insoles and exercise program. Kulig et al. showed a remarkable effect of custom made insole in conjunction with eccentric exercises in FFI values of stages 1–2 PTTD subjects [7]. On the other hand, Houck et al. showed similar improvements in FFI after 3-month stretching and strengthening programs applied together with prefabricated insole [12].

Low level laser therapy (LLLT) came into use in soft tissue treatment half a century ago [13]. The preferred wavelengths for LLLT are in the range of 660–905 nm, which penetrate tissue more effectively to stimulate healing by photochemical reactions [14]. LLLT, has a potential effect on stimulating collagen synthesis with neovascularization of healing [15]. Studies show that LLLT is effective in healing tendinopathies, such as lateral epicondylitis, supraspinatus and Achilles [15, 18]. Marcos et al. [19] have shown the LLLT as an alternative to anti-inflammatory drugs for healing of tendinitis in rat Achilles. LLLT may be an effective option for healing of tendinopathy of tibialis posterior also. Although, the other conservative treatment approaches were investigated before, no study examined the effectiveness of LLLT method in the treatment of PTTD. Therefore, we questioned whether the LLLT is effective in controlling symptoms as offloading insole in PTTD. The aim of this study was to compare the effects of insoles and LLLT on pain, function and muscle strength in PTTD.

2. Materials and methods

2.1 Study design

This randomized comparative study included subjects of 18–60 years of age who were diagnosed with stage II-A1 and II-A2 PTTD, with flexible hindfoot valgus, painful posterior tibial tendon with flexible or fixed forefoot varus in clinical examination as described by Bluman et al. [5]. The study was conducted between 17.06.2017 and 22.12.2018 in an outpatient clinic. All of the subjects who agreed to participate in the study signed a written informed consent form, which was approved by the Research Publication and Ethics Board of Eastern Mediterranean University with number 2017/45-14. This clinical study was registered to clinicaltrials.gov with number NCT03363074 prior to allocation of subjects.

Figure 1.

Flowchart.

2.2 Subjects

Subjects who had not received any treatment on the foot within the last 1 year and who were able to ambulate independently were included in the study. On the other hand, subjects with different orthopedic, neurological, or arthritis that might affect lower extremity biomechanics and with a lower extremity length inequality of more than 1 cm were excluded from the study. In addition, the subjects who were using any medications for PTTD were not included. According to the power analysis performed with the software G-Power (Kiel University, Kiel, Germany) assuming that nonparametric Mann-Whitney U test would be used for comparison between two groups, a two-legged hypothesis was established and based on Cohen $d=$ 0.8, $\alpha=$ 0.05, $\beta=$ 0.20, a total of 52 people were taken into the calculation as 26 people in each group. As a result, accounting for a loss of 15%, it was planned to recruit 60 subjects in total. After the completion of the treatment, subjects were followed up for 9 months. All assessments at 9th month were repeated with the subjects who could come to the clinic (insole: 20, LLLT: 19). Foot Function Index (FFI) and the International Physical Activity Questionnaire (IPAQ) scales were questioned by phone calling for the left 13 subjects who could not come (insole: 6, LLLT: 7) (Fig. 1).

2.3 Randomization

The subjects were randomly assigned to the interventions by the first author with the arrival order to the pre-defined groups according to the randomized order created by an independent researcher with Random Allocation Software version 1.0.0 (Isfahan University, Isfahan, Iran).

2.4 Outcome measures

In the first evaluation of the subjects, socio- demographic data was collected such as name, surname, age, gender, dominant side, height, body weight and affected side. The foot posture of the subjects was assessed using the Foot Posture Index (FPI) to see any difference between groups, whereby $+$ 6 and above was interpreted as increased pronation and $-$ 6 and below as increased supination [20]. All subjects included in the study had pronation posture. Considering that the level of physical activity might affect treatment, the IPAQ was applied [21]. The primary outcome of our study was FFI. In addition, isokinetic dynamometer were used to determine the treatment outcomes. In the analysis, the results of the assessment of the foot subject to more subject complaints were used. Following the assessment, subjects were randomly allocated to LLLT and insole groups. All these assessment and LLLT were done by the same physiotherapist and all insoles were produced by the same orthotist.

2.4.1 Foot function index

FFI is a valid and reliable scale to assess the severity of foot pain in different situations, as well as how it affects physical involvement in various activities. The scale consists of 23 questions to be scored from 0 to 10, with increased scores indicating increased pain and decreased activity and participation. The result of the score obtained over 230 is calculated as a percentage [22]. The Turkish version of the Index was used in our research [23].

2.4.2 Assessment of the muscle strength

Eccentric and concentric muscle strength of the invertor and evertor foot muscles were assessed using an isokinetic dynamometer (Humac Norm, CSMi, USA). Assessment of ankle invertor and evertor muscle strength with isokinetic dynamometer was shown as a reliable technique by Aydoğ et al. [24]. Before starting the test, the subjects were given a standard warm-up program for 3 minutes without resistance on the bicycle ergometer. Angular velocities of 180 ${}^{\circ}$ .sec ${}^{-1}$ and 240.sec ${}^{-1}$ were used to evaluate the invertor and evertor muscle strength. Measurements were made with the subject in supine position, hip and knee flexed at 90 ${}^{\circ}$ and the other lower extremities, chest and waist were fixed with Velcro bands. The foot was placed on the platform of the dynamometer arm with the person in own sneakers and supported by cross bands [25]. After 3 repetitive trials at each angular velocity, 10 repetitive measurements were performed with a 10-second rest interval between each measurement.

2.5 Interventions

2.5.1 Insole

For the insole manufacture, first of all, foot plantar pressure values of the subjects were obtained with a pedobarograph (Medilogic, platform basic, Germany) using the 2-step method on a 5 meters floor [26]. Modeling was based on the foot plantar pressure and foot postures of the subjects. The computer-aided modeling process involved adding the MLA (8–12 mm) and transverse arch (4–6 mm) supports on the insoles of all subjects and 6 ${}^{\circ}$ medial heel wedge corrective pads were used for subjects with a calcaneal eversion over 5 ${}^{\circ}$ , similarly to previously described [27]. Pads were located according to borders of foot plantar pressure data; just proximal of metatarsal heads from second to fourth for transvers arch, medial two-thirds of midfoot for MLA and medial two-thirds of hindfoot for medial heel wedge. Insoles were manufactured from Ethyl Vinyl Acetate of Shore A 35 hardness and placed inside the sneakers (Fig. 2). Subjects were required to record the time (in minute) they used their insoles each day for 8 weeks.

Figure 2.

Insole.

Table 1

Comparison of baseline characters of insoles and low level laser therapy group

	Insole $n=$ 26		LLLT $n=$ 26		$p^{\ast}$
	Median (IQR)
Age (y)	24.0	(5)	22.0	(3)	0.003 ${}^{\ast}$
Body mass (kg)	77.5	(20)	68.0	(21)	0.210 ${}^{\ast}$
Height (cm)	170.0	(10)	167.0	(17)	0.469 ${}^{\ast}$
Body mass index (kg/m ${}^{2}$ )	25.0	(6.4)	23.9	(3.6)	0.319 ${}^{\ast}$
Foot posture index	9.0	(3)	8.0	(1)	0.972 ${}^{\ast}$
IPAQ	495.0	(577.5)	330.0	(428.1)	0.132 ${}^{\ast}$
Insoles usage time (min/day)	160.7	(114.6)	–
Affected side (%)
Unilateral	86.4		88.5		0.565 ${}^{\yen}$
Bilateral	15.6		11.5

${}^{\ast}$ : Mann-Whitney U test, ${}^{\yen}$ : Chi-Square Test, IPAQ: International Physical Activity Questionnaire, LLLT: Low-Level Laser Therapy, IQR: Interquartile Range.

2.5.2 LLLT

Laser device (Cattanooga Vectra Genisys Transport, Cattanooga Group, USA) and a Ga/Al/As laser beam of 850 nm wavelength and 100 microwatt (mW) power were used. In the LLLT group, a treatment dose of 0.7–7 (j/cm ${}^{2}$ ) Ga/Al/As was used bilaterally at a wavelength of 850 nm 3 days a week with 14 sessions in total. The dosage, power, and duration were determined based on the previously published review by Bjordal et al. [28]. The application was perpendicular to the 3 points of the tibialis posterior tendon (Fig. 3). The LLLT was applied on one point of the tendon for 55 seconds by using a single probe, and each treatment session lasted approximately 6 minutes for two feet. Subject was in the side-lying position on treatment bed during the LLLT application. LLLT group was also advised to wear similar type of sneakers as insole group during treatment.

Figure 3.

Laser application regions.

2.6 Statistical analyses

The software SPSS (Statistical Package for Social Sciences, IBM, New York, USA) was used for data analysis. The normal distributions of the data were examined using the Shapiro-Wilk test. For the comparison of normally distributed data, paired $t$ -test (intra-group comparison) and independent $t$ -test (inter-group comparison) were used but when parametric conditions could not be met, the Wilcoxon test and Mann-Whitney U test were used to compare intra and inter-group changes respectively. Chi-Square and Fisher’s Exact Chi-Square Tests were used for categorical variables. The effect of multiple continuous independent variables on the dependent variable was assessed through a General Linear Model analysis. Measurements that showed differences between groups prior to the treatment were taken as covariant, and statistical significance was accepted as $p<$ 0.05 in all analysis. Furthermore, the effect size (Cohen’s d) of the treatments was calculated and 0.20–0.49 was accepted as small, 0.50–0.79 as medium, and 0.80 and higher as large effect [29].

3. Results

Non-parametric tests were used test for all comparisons because normal distributions were not achieved for all comparisons, according to Shapiro-Wilk test and all variables were given as median with 25–75% interquartile range. Gender distribution, the values of body mass index (BMI) and foot posture index and the patterns of involvement were similar across groups ( $p>$ 0.05), but the mean age of the insole group was higher than that of the LLLT group ( $p<$ 0.05) (Table 1). Even though the FFI values improved significantly in both groups after treatment and follow-up, at the end of 9 months the insole group had significantly better scores than the LLLT group ( $p<$ 0.05) (Table 2) (Fig. 4). Physical activity levels increased significantly in both groups during follow-up, but it was higher in the insole group ( $p<$ 0.05) (Table 2).

Table 2
A comparison of FFI and IPAQ between groups

		B		AT		9 month		B-AT	B-9 month
		Median (IQR)						$p^{*}$ $d^{{\ddagger}}$	$p^{*}$ $d^{{\ddagger}}$
FFI (total point)	Insole	27.3	(15.9)	12.3	(7.6)	16.3	(6.4)	$<$ 0.001	$<$ 0.001
								1.405	1.204
	LLLT	22.8	(9.5)	16.6	(6.5)	20.8	(6.8)	$<$ 0.001	0.002
								1.258	0.641
	$p^{\yen}$	0.395		0.070		0.004
	$d^{{\ddagger}}$					0.714
IPAQ (kcal)	Insole	495.0	(577.5)	830.1	(628.8)	1885.0	(667.5)	$<$ 0.001	$<$ 0.001
								0.307	0.443
	LLLT	330.0	(428.1)	433.1	(548.0)	495.0	(355.7)	$<$ 0.001	0.001
								0.278	0.287
	$p^{\yen}$	0.132		0.002		$<$ 0.001
	$d^{{\ddagger}}$			0.404		0.609

${}^{*}$ : Wilcoxon Signed Rank Test. ${}^{\ddagger}$ : Effect Size, ${}^{\dagger}$ : General Linear Model Univariate Analysis, ${}^{\yen}$ Mann-Whitney U test, B: Baseline, AT: After Treatment, FFI: Foot Function Index, IPAQ: International Physical Activity Questionnaire, IQR: Interquartile Range.

Figure 4.

A comparison of foot function index between groups.

No difference was found between the two groups in terms of muscle strength at baseline, post-treatment, and at the end of 9 months ( $p>$ 0.05). At 180 ${}^{\circ}$ .sec-1 angular velocity, the concentric inverter muscle strength was higher in both groups after treatment and after 9 months ( $p<$ 0.05), but the effect size was small. As for the evertor muscle strength, the concentric evertor muscle strength at 180 ${}^{\circ}$ .sec-1 angular velocity significantly increased in both groups at the end of the 9-month follow-up period ( $p<$ 0.05), but the effect sizes remained small (Table 3).

Table 3

A comparison of muscle strength of between groups

Muscle strength		B		AT		9 month		B-AT	B-9 month
		Median (IQR)						$p^{\ast}$ $d^{{\ddagger}}$	$p^{\ast}$ $d^{{\ddagger}}$
Invertor concentric 180 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	16.0	(8)	18.0	(19)	20.0	(12)	0.038	0.005
								0.133	0.365
	LLLT	15.0	(9)	16.0	(10)	16.0	(11)	0.016	0.010
								0.264	0.219
	$p^{\yen}$	0.876		0.582		0.464
Invertor eccentric 180 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	22.0	(15)	24.0	(17)	28.0	(22)	0.821	0.265
	LLLT	20.0	(14)	22.0	(14)	21.0	(10)	0.482	0.089
	$p^{\yen}$	0.764		0.975		0.819
Invertor concentric 240 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	15.0	(8)	18.0	(8)	18.0	(10)	0.041	0.006
								0.296	0.127
	LLLT	14.0	(11)	14.5	(11)	12.0	(10)	0.246	0.190
	$p^{\yen}$	0.854		0.653		0.405
Invertor eccentric 240 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	20.0	(16)	20.0	(14)	22.0	(18)	0.890	0.425
	LLLT	18.0	(9)	19.0	(11)	19.0	(8)	0.242	0.713
	$p^{\yen}$	0.475		0.881		0.680
Evertor concentric 180 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	16.0	(11)	18.0	(14)	22.0	(9)	0.972	0.003
									0.071
	LLLT	16.0	(10)	18.0	(12)	17.0	(10)	0.006	0.001
								0.220	0.161
	$p^{\yen}$	0.927		0.457		0.311
Evertor eccentric 180 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	30.0	(17)	22.0	(19)	33.0	(22)	0.177	0.004
									0.46
	LLLT	22.0	(12)	23.0	(9)	24.0	(7)	0.480	0.082
	$p^{\yen}$	0.341		0.741		0.136
Evertor concentric 240 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	15.0	(10)	16.0	(9)	18.0	(10)	0.147	0.285
	LLLT	14.5	(8)	12.0	(10)	16.0	(9)	0.980	0.082
	$p^{\yen}$	0.949		0.419		0.632
Evertor eccentric 240 ${}^{\circ}$ .sec ${}^{-1}$ (Nm)	Insole	18.0	(18)	18.0	(14)	21.0	(11)	0.164	0.393
	LLLT	19.0	(12)	22.0	(10)	18.0	(5)	0.015	0.916
								0.380
	$p^{\yen}$	0.893		0.118		0.494

${}^{\ast}$ : Wilcoxon Signed Rank Test. ${}^{{\ddagger}}$ : Effect Size, ${}^{\yen}$ : Mann-Whitney U test, B: Baseline, AT: After Treatment, FFI: Foot Function Index, LLLT: Low-Level Laser Therapy, IQR: Interquartile Range.

4. Discussion

This study was a comparative evaluation of the effects of insole and LLLT on pain, function and muscle strength in subjects with stage II-A1 and II-A2 PTTD. Both methods were effective in terms of pain control and improving function in the short term, but insoles were more effective in the long term. While it was observed that both methods improved the strength of concentric inverter and evertor muscles at an angular velocity of 180 ${}^{\circ}$ .sn ${}^{-1}$ the effect sizes of these increases were small.

To our knowledge, this is the first study to compare the effects of insole vs. LLLT applications in the conservative treatment of PTTD. Various orthoses are already in use to reduce the workload of the posterior muscle of the tibialis in the conservative treatment of PTTD, but LLLT, used in the healing process of tendinopathies emerges as an alternative in conservative treatment. The higher rate of improvement in pain and function in the insole group at the end of 9 months as compared to the LLLT group may be due to the fact that subjects continued to use their insoles during this period. This method was chosen as it would not be ethically acceptable to force the subjects to stop using insoles for the follow-up. On the other hand, even though the values measured at the end of 5 weeks showed a decline at the end of month 9, the effect of the treatment continued nevertheless.

In the literature, LLLT is demonstrated to be capable of increasing neovascularization and reducing inflammation findings [30]. The main mechanism of action of laser is tissue stimulation. It is reported to boost vascular structure, interstitial tissue, and immune system through this basic mechanism [31]. Laser increases the penetration of mediators required for wound healing into the cell by allowing ions to pass through the cell membrane more easily. Moreover, animal studies involving experimental cartilage destruction report clinically and histologically significant improvement with laser treatment [32]. As for the analgesic effect of LLLT, it relies on reactive vasodilatation by reducing spasm in muscle arterioles causing a sensation of pain at sensory nerve endings [31]. In addition, LLLT is known to induce analgesia by enhancing peripheral endogenous opioid production [33]. On the other hand, the potential placebo effect of application should not be overlooked even though the reported efficacy of the LLLT were over placebo for shoulder tendinopathies [34]. All of these mechanisms may explain how LLLT reduces pain at subjects with PTTD. However, in the clinical results in the literature that match the findings of our study, it is found that LLLT reduces pain caused by various soft tissue problems in the short term, but the pain relief effect is decreased clinically in the long term [18, 32]. This suggests that the use of LLLT alone in conservative treatment will not be effective in the long term probably because of ongoing increased mechanical loading on tendon.

Orthotic designs in PTTD studies were varied such as Arizona brace, UCBL or hinged AFO, according to severity of subjects some of whom had stage 3 PTTD [8, 10, 11].

In these studies, more aggressive offloading orthotics were used to control symptoms when compared with our insole treatment. We only made insoles for the subjects with stage 2 PTTD and our results were obtained in a shorter term in comparison to other studies. However, our findings shows that the insole therapy is clinically effective in pain reduction and functional improvement in this term but in subjects without severe pathology. Accordingly, it is stated in these studies that orthosis might be more successful in the early stages of pathology. Our follow-up was relatively short in comparison to above mentioned studies. The long-term effect of insoles is still unclear with these results and should be investigated.

Similar to our study, Kulig et al. [7] and Houck et al. [12] showed improvement in PTTD with insole treatment. Our study did not contain any exercise program, yet reported a clinically important decrease in the FFI [35]. The improvements of these studies are similar to us, but Kulig et al. showed that supervised eccentric exercise could produce better results when included in the treatment together with the orthosis. Even though our study did not include a muscle strengthening program, we examined the effects of insoles and LLLT on muscle strength. No difference was found between the two methods in terms of muscle strength, however, at the end of the 9th month, an increase in the concentric 180 ${}^{\circ}$ .sec ${}^{-1}$ angular velocity of the invertor and evertor muscles was recorded in both groups. These results might have been affected because of drop-outs in long term follow-up. Nevertheless, an examination of the effect sizes showed that this increase was not clinically significant. This result shows that no significant change can be attained in the tibialis posterior muscle strength either with insoles or LLLT alone. Alvarez et al. support this finding with their results showing that the 4-month supervised progressive strengthening exercise program with orthosis induced a significant increase in the muscle strength of the invertors while orthosis alone did not [36].

Another important finding of our study was the increased physical activity level of subjects, especially in the insole group, after treatment and follow-up. Increased physical activity could be the result of decreased pain during activity. Moreover, increased activity might have stimulated healing progress of tendon with controlled mechanical loading with the insole. Although, we did not give any exercise program to subjects, it is not easy to say that daily activities have no treatment effect on tendon.

The mechanisms of activity of the insoles and LLLT treatments used in our study are rather different. LLLT treatment aims to stimulate tendon healing, whereas insoles are used to improve healing by reducing tension forces on the tendon. Both methods can be used in the conservative treatment of PTTD to relieve pain and improve function, but it is also possible to use them together to achieve faster and more effective results. Future studies to investigate the efficacy of treatment with an LLLT and orthosis combination will be an important contribution in this regard. The efficacy of exercise is better known in different tendinopathies such as Achilles tendinopathy, but studies in tibialis posterior tendinopathy do not suffice [37]. As seen in our study, it does not seem likely to secure a significant improvement in muscle strength through the use of insoles or LLLT alone. Therefore, randomized controlled trials of combined treatment protocols, including exercise programs to increase muscle strength, will help close the knowledge gap in this area.

4.1 Limitations

The sample size, randomized design, and a 9-month follow-up period are the strengths of our study, but it has its limitations as well. First, the lack of a control group without any treatment limited our results, and this should be taken into account in clinical reasoning. In addition, the mean age of the subjects was lower than other studies in the literature. Also, their BMI values were not so high and they had no comorbidity. Even though PTTD is a pathology more common in middle age and older age groups with increased BMI, it may well affect younger subjects. The reason this age group is affected more might be the increased physical workload, especially with subjects with a foot over pronation deformity join the workforce. It is possible that their young age brought a positive effect on the results and the lack of a control group with no treatment prevented us from observing this effect. There is a risk of bias because the participants and the clinicians were not blinded in the study. The high drop-out rate for the muscle assessment in the long term might have affected the findings of ankle muscle strength. In addition, both groups were advised to wear similar sneakers but we do not know how much they wore them. However, we observed that most of the subjects were wearing sneakers already probably because of their pain on feet. Also, varied features of sneakers might have affected the outcomes, especially in insole group because of insole footwear interaction.

5. Conclusion

We found that insole and LLLT treatments were effective in reducing tendon sensitivity and treating pain, as well as improving the functioning in subjects with stage II-A1 and II-A2 PTTD. However, at the end of the 9-month follow-up, it was seen that continued use of insoles was more effective than short term LLLT. On the other hand, neither method had a clinically significant effect on muscle strength.

Footnotes

Conflict of interest

None to report.

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Comparison of the effects of low level laser and insoles on pain,functioning,and muscle strength in subjects with stage 2 posterior tibial tendon dysfunction: A randomized study

Abstract

BACKGROUND:

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Keywords

1. Introduction

2. Materials and methods

2.1 Study design

2.3 Randomization

2.4 Outcome measures

2.4.1 Foot function index

2.4.2 Assessment of the muscle strength

2.5 Interventions

2.5.1 Insole

3. Results

Table 2 A comparison of FFI and IPAQ between groups

4.1 Limitations

5. Conclusion

Footnotes

Conflict of interest

References

Table 2
A comparison of FFI and IPAQ between groups