The aim of the research was to assess the effectiveness of the quadriceps muscle electro stimulation in patients after reconstruction of anterior cruciate ligament, with the use of HiToP therapy. The obtained results indicate the overall low effectiveness of HiToP, however, the results of the selected outcome measures allow to assess the use of HiToP as an effective.
Injury of the ACL mostly concern young and active people who get injured during recreational or professional physical activity. Comprehensive physiotherapy covering both kinesitherapy and physical therapy is aimed at restoring motor skills in patients after ACL reconstruction. The mobility depends on the adequate level of knee muscles strength, range of motion, proprioception. Immediately after the reconstruction the range of motion in the knee joint is limited by pain and swelling. Such a limitation does not have a positive influence on muscle strength, particularly knee extensors. Researchers agree that after rehabilitation the values of muscle strength should be similar to those from before the surgery [20,21,22]
One of the elements of therapy of patients after ACL reconstruction can be electrostimulation of the quadriceps muscle, which helps to rebuild muscle strength. Currently, in the rehabilitation of patients after ACL reconstruction HiToP is used, which in addition to muscle stimulation supports cell metabolism, thereby reducing pain [8].
In the available literature there is, however, lack of reports on the effectiveness of the use of the HiToP in patients after ACL reconstruction. There are also no publications including the analysis of the results of knee extensors strength measurements in patients after ACL reconstruction in whom the HiToP was used.
One of the few authors who undertook the evaluation of the effectiveness of HiToP in rehabilitation of patients with soft tissue injuries was Wilk et al. They indicate the improvement in muscle strength of knee extensors after including the HiToP therapy into rehabilitation [9].
Also in the studies of Janiszewski et al., who analyzed the use of HiToP in patients with pain in the lumbar spine, after using the therapy, the strength of the muscles stabilizing the spine improved [23].
Kulis et al. also confirm the effectiveness of HiToP in the therapy of patients with cervical spine pain [24]. The authors conducted a study on a group of 40 people who used HiToP twice a week for 30 minutes for a period of 3 weeks. Test results show an improvement in the mobility of the cervical spine and a reduction in back pain.
Czamara et al. present the study which shows the results suggesting that after ACL reconstruction there is always a decline in muscle strength torque in the operated limb resulting from, inter alia, a reduced activity following the surgery [21]. The authors studied the effect of physiotherapy on extensors and flexors strength in a group of men where each of them had an individual therapeutic program with a similar therapeutic procedure as the patients in this research, also complemented by electrical stimulation of the quadriceps. The authors conclude that the therapy aimed at restoring muscle strength of the knee allows to achieve results similar to the non-operated limb.
Studies of other authors, however, demonstrate that not always balance in muscle strength occurs. Urabe et al. undertook research involving the analysis of the measurement of knee and hip strength in patients after ACL reconstruction [25]. They conclude that after 12 months of rehabilitation they did not obtain in the operated limb the improvement of muscle strength that would be similar to the results of the healthy limb.
Own research showed that there were no statistically significant differences between the results of I and II measurement of muscle strength in injured leg, separately for both groups and between the groups.
Measurement of thigh circumference, which is the determinant of the growth of muscle mass and strength, showed improvement after rehabilitation. In the Control group the result proved to be statistically significant, whereas in the Experimental group no statistically significant difference was noted, however, there was a trend towards significance of the result.
Another aspect addressed in this study was the influence of the HiToP on resorption of swelling in the knee.
Nowakowska et al. in their study observed increased blood flow in the microcirculation of the lower limbs after applying the HiToP [10]. It is possible that in the case of patients after ACL reconstruction in whom the HiToP was used a similar phenomenon occurred, which resulted in reduction of swelling and the lack of effusion after applied therapy.
The results of own research indicate a reduction in the knee circumference in both analysed Groups, suggesting a reduction of swelling, however, these differences were not statistically significant.
The impact of the HiToP on the range of motion was analyzed by Wilk et al. who, after the therapy, found improvement in the knee range of motion [9].
In own research the results of the measurements of the range of extension indicate that there were no differences that could significantly support the better recovery of patients treated with HiToP. Interesting results were also obtained by Janiszewski et al. where after using HiToP in patients with degenerative changes in the lumbar spine, the mobility of the spine improved [23].
One of the issues that were addressed in this study was the influence of the HiToP on pain. Wilk et al., on the grounds of their studies, conclude that pain is reduced in patients after the HiToP [9].
Analysis of subjective evaluation of pain in patients after ACL reconstruction showed reduction of pain in both tested Groups. Better results were obtained by patients whose rehabilitation included the HiToP therapy, but the differences between measurements and between Groups were statistically insignificant.
Study Limitations
Analysis of studies of other authors shows the positive impact of the HiToP on the strength and function of the knee in patients after ACL reconstruction. The results obtained in this study are, however, ambiguous. The cause of such results can be for example low frequency of treatments during the week – from 3 days a week for the first 3 months up to 2 times a week for the next 3 months. The best results of electrostimulation are obtained by applying the therapy every day, what was proved by, among others, Wilk et al. and Ziółkowska et al. [9,26].
Another aspect is the patients’ approach to physiotherapy. Unfortunately, most people think that they do need to exercise too intensely or perform exercises at home once they have electro stimulation. Patients who did not have an additional therapy were more motivated to exercise. Such an attitude could result in insignificant differences between the Groups. Rehabilitation in both Groups was identical, but the results were very similar and all patients achieved their goals. That is why, even rehabilitation and appropriate proceedings alone bring beneficial effects.
There are few scientific reports which would show that the inclusion of the HiToP therapy into the rehabilitation program gives better results. However, part of the results of this research, although statistically insignificant, from the therapeutic point of view is an important signal that the use of HiToP therapy in rehabilitation of patients after ACL reconstruction as well as after other surgeries or injuries brings effects. Therefore, it is worth to expand this issue in future by modifying the frequency and extending therapy.