SLR - September 2014 - Samantha DelRegno

Effect of Shockwave Therapy on Plantar Fasciopathy: A Biomechanical Prospective

Reference: Hsu WH, Lai LJ, Chang HY, Hsu RW. Effect of Shockwave Therapy on Plantar Fasciopathy: A Biomechanical Prospective.  Bone Joint J. 2013; 95-B(8):1088-93.

Scientific Literature Review

Reviewed By: Samantha DelRegno, DPM
Residency Program: Englewood Hospital and Medical Center, Englewood, NJ

Podiatric Relevance: Heel pain is one of the most frequent complaints podiatric physicians encounter daily in their office, the most common cause of this pain being plantar fasciopathy. Although the exact mechanism causing this fasciopathy is unknown, many pre-disposing factors include, but are not limited to, poor foot contact strategy, excessive foot pronation, and tight calf musculature, including that of the tendoachilles. Treatment options for this diagnosis may include orthotics, steroid injection, and surgery, amongst many other therapies. The purpose of this study is to evaluate the use of extracorporal shockwave therapy (ESWT) for treatment of plantar fasciopathy and to evaluate changes in patient kinematics and kinetics pre- and post-treatment.

Methods: This is a prospective biomechanical study from Chang Gung Memorial Hospital at Chia Yi, Taiwan. This study analyzes 12 female patients between January 2010 and 2011 with a diagnosis of unilateral plantar fasciopathy. The mean age of these subjects was 59 years (50 to 70), mean body mass index 25 kg/m2 (22 to 30), mean duration of symptoms 9.3 months (6 to 15), and mean pain on the visual analog scale (VAS, 0 denoting no pain and 10 maximum pain) 6.3 (5 to 8). Inclusion criteria were localized pain to the insertion of the plantar fascia at the plantar medial tubercle of the calcaneus and pain after a period of non-weightbearing with duration of symptoms greater than six months. Exclusion criteria were bilateral plantar fasciopathy, co-morbidities causing peripheral neuropathy, and peripheral arterial disease. Each patient participating in the study received three treatments with ESWT, three weeks apart, with 1,500 shock waves delivered per session at an energy flux density of 0.26 mJ/mm2 and a rate of 1Hz. The point of application was identified via palpation and locating the insertion of the plantar fascia with the use of sonography. Pre-treatment plantar forces and pressures were recorded during barefoot walking. Each patient took five passes across a 5mm thick floor mat consisting of 33 792-resistive sensors. Data was then collected from the Tekscan Walkway Research Software v.7 for step and gait time, distance, velocity, cadence, and gait cycle. Additional information was able to be extracted for four segments of the foot (hindfoot, midfoot, forefoot, and digits) including contact duration (ms), maximum force (% body weight), peak contact pressure (kPa), contact area (cm2), and impulse (% body weight x seconds). In addition, the impulse of the entire foot for the plantar surface area was calculated, as well as the arch index. Further kinetic analysis was performed utilizing an optoelectronic eight-camera Vicon motion analysis system at 100Hz during five walking trials. Data was then processed using the Nexus motion analysis system. Statistical analysis was performed using a two-way analysis of variance (ANOVA) for differences between the symptomatic and asymptomatic foot pre and post-treatment, a one-way ANOVA to determine statistical significance for gait parameters and a paired t-test for comparison of cadence and walking velocity before and after treatment.

Results: Following ESWT the mean VAS was 3.7 (three to five). No difference was noted between gait patterns on opposing limbs, and patient gait velocity and cadence was also increased. Peak contact pressure increased from a mean of 429kPa to 479kPa. Contact area of the digits decreased from 11.8cm2 to 10.8 cm2, while contact pressure over the forefoot increased. The arch index between both feet before and after treatment remained the same. There were no differences in contact duration. Centre of pressure (COP) duration remained increased in the symptomatic foot before and after treatment, while the differences in trajectory before and after treatment decreased.

Conclusions: In this prospective biomechanical study, it was shown in 12 consecutive female patients that ESWT helped to decrease their heel pain secondary to plantar fasciopathy on the VAS scale. It demonstrated improvement in gait parameters of the symptomatic foot following treatment with ESWT. By increasing the peak forefoot pressures, the patients were able to restore a more normal gait pattern. With an increase in cadence and velocity during gait, it was also found that the patients had a functional improvement. This study recognizes that ESWT should continue to be at the forefront of treatment options for heel pain secondary to plantar fasciopathy.  It is important not only in the temporary relief of patient plan, but in long term gait adjustments leading to better functioning kinetics and kinematics.

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