Potential Role of High Voltage Monophasic Pulsed Current on the Healing of Chronic Tendinopathy

Abstract

Tendinopathy is a common clinical condition characterized by pain and dysfunction which may become chronic or recurrent. An umbrella review of systematic reviews, that were published in the last decade, showed that current physical therapy interventions for tendinopathy may be supported by insufficient evidence. The role of high-voltage monophasic pulsed current (HVMPC) as a potential treatment for tendinopathy was, consequently, thought to be evaluated. Dermal ulcers, as possible examples of failed healing response and possibly the most common application of HVMPC, were chosen to determine and quantify the effects of HVMPC. Level I, II and IV evidence studies indicated that HVMPC plus standard wound care (SWC) were more effective than SWC alone or SWC plus sham HVMPC in treating stage II-IV pressure ulcers (PrUs). HVMPC plus SWC were found to reducewound surface area by 12.39% per week; 95% CI, [10.43,14.37] compared with 6.96% per week; 95% CI, [5.56, 8.38] for SWC alone or SWC plus sham HVMPC. Moreover, HVMPC plus SWC likely increased the probability of complete wound healing of PrUs compared with sham/no HVMPC plus SWC; relative risk (RR) 2.08; 95% CI: [1.42, 3.04], p = 0.0002; I2 = 0%, p = 0.61; eight studies, 358 ulcers. In order to investigate whether HVMPC effects on PrUs could be transferred to chronic tendinopathy, an animal model of overuse-induced tendon injury was developed, to which the influence of HVMPC intervention was examined. Reproducible injury of Achilles tendons, on cellular and genetic levels, was sustained for at least 15 and 30 days following the end of protocol, respectively, and up to 60 days with administration of dexmedetomidine injections. The results might provide an insight into the changes that may delineate overuse-induced tendon injury, and possibly precede tendinopathy. HVMPC intervention might have augmented insertional ground-substance content compared with sham HVMPC; at 30-day timepoint; difference between medians= - 0.8300; Hodges-Lehmann= -0.8200; Sham HVMPC= 0.7600, n= 43; HVMPC= 1.590, n= 44; U= 433.5; P= <0.0001, and at 45-day timepoint; difference between medians=0.5300; Hodges-Lehmann=0.6600; Sham HVMPC= 1.520, n= 55; HVMPC= 2050, n=57; U= 1220; P= 0.0430. Nonetheless, a non-statistically significant difference was found at the 60-day timepoint post overuse tendon injury; difference between medians= -0.1700; Hodges-Lehmann= -0.4300; Sham HVMPC= 1.630, n= 59; HVMPC= 1.800, n= 59; U= 1440; P= 0.1057. In addition, HVMPC intervention might have increased calcification compared with sham HVMPC at both the 30-day and the 45-day timepoints. These results collectively suggest that HVMPC might have a potential beneficial role in treating chronic tendinopathy.