I-ONE therapy in patients undergoing total knee arthroplasty: a prospective, randomized and controlled study

Abstract

Background: Total knee arthroplasty (TKA) is often associated with a severe local inflammatory reaction which, unless controlled, leads to persistent pain up to one year after surgery. Standard and accelerated rehabilitation protocols are currently being implemented after TKA, but no consensus exists regarding the long-term effects. Biophysical stimulation with pulsed electromagnetic fields (PEMFs) has been demonstrated to exert an anti-inflammatory effect, to promote early functional recovery and to maintain a positive long-term effect in patients undergoing joint arthroscopy. The aim of this study was to evaluate whether PEMFs can be used to limit the pain and enhance patient recovery after TKA.

Methods: A prospective, randomized, controlled study in 30 patients undergoing TKA was conducted. Patients were randomized into experimental PEMFs or a control group. Patients in the experimental group were instructed to use I-ONE stimulator 4hours/day for 60days. Postoperatively, all patients received the same rehabilitation program. Treatment outcome was assessed using the Knee Society Score, SF-36 Health-Survey and VAS. Patients were evaluated pre-operatively and one, two, six and 12 months after TKA. Joint swelling and Non Steroidal Anti Inflammatory Drug (NSAID) consumption were recorded. Comparisons between the two groups were carried out using a two-tail heteroschedastic Student's t-test. Analysis of variance for each individual subject during the study was performed using ANOVA for multiple comparisons, applied on each group, and a Dunnet post hoc test. A p value < 0.05 was considered statistically significant.

Results: Pre-operatively, no differences were observed between groups in terms of age, sex, weight, height, Knee-Score, VAS, SF-36 and joint swelling, with the exception of the Functional Score. The Knee-Score, SF-36 and VAS demonstrated significantly positive outcomes in the I-ONE stimulated group compared with the controls at follow-ups. In the I-ONE group, NSAID use was reduced and joint swelling resolution was more rapid than in controls. The effect of I-ONE therapy was maintained after use of the device was discontinued.

Conclusions: The results of the study show early functional recovery in the I-ONE group. I-ONE therapy should be considered after TKA to prevent the inflammatory reaction elicited by surgery, for pain relief and to speed functional recovery.

Figure 1

I-ONE therapy. Left: waveform of magnetic field 1.5 mT peak value (top); waveform of induced electrical field 0.051 mV/cm peak value, as detected using a standard coil probe (50 turns, 0.5 cm internal diameter of the coil probe, 0.2 mm copper diameter) (bottom). Right: I-ONE PEMF generator.

Figure 2

Knee Score. Mean values of Knee Score in the control group and I-ONE therapy group during the study. Vertical bars represent the standard error. *p < 0.0001, p values refer to a comparison between groups at each follow-up visit by two tailed heteroschedastic Student’s t-test. ⁺p < 0.05, statistically significant difference versus pre-op.

Figure 3

Functional Score.(A) Mean values of Functional Score in the control group and I-ONE therapy group during the study. Vertical bars represent the standard error. *p < 0.0001, ^p < 0.005, ^§p < 0.05, p values refer to a comparison between groups at each follow-up visit by two tailed heteroschedastic Student’s t-test. ⁺p < 0.05, statistically significant difference versus pre-op. (B) Mean changes in Functional Score in control and I-ONE groups during the follow-up compared with baseline values. Vertical bars represent standard errors.

Figure 4

SF-36 Health Survey Score. Mean values of SF-36 Health Survey in the control group and I-ONE therapy group during the study. Vertical bars represent the standard error. *p < 0.0001, ^§p < 0.05, p values refer to a comparison between groups at each follow-up visit using two tailed heteroschedastic Student’s t-test. ⁺p < 0.05, statistically significant difference versus pre-op.

Figure 5

VAS Score. Mean values of VAS in the control group and I-ONE therapy group during the study. Vertical bars represent the standard error. *p < 0.0001, °p < 0.001, ^§p < 0.05, p values refer to a comparison between groups at each follow-up visit using two tailed heteroschedastic Student’s t-test. ⁺p < 0.05, statistically significant difference versus pre-op.