A double-blind trial of pulsed electromagnetic fields for delayed union of tibial fractures. Pulsed magnetic field therapy for tibial non-union. Interim results of a double-blind trial. Electrical treatment of tibial non-union: a prospective, randomised, double-blind trial. A prospective, double-blind trial of electrical capacitive coupling in the treatment of non-union of long bones.
A total of 45 tibial shaft fractures, all conservatively treated and with union delayed for more than 16 but less than 32 weeks were entered in a double-blind multi-centre trial. The fractures were selected for their liability to delayed union by the presence of moderate or severe displacement, angulation or comminution or a compound lesion with moderate or severe injury to skin and soft tissues. Treatment was by plaster immobilisation in all, with active electromagnetic stimulation units in 20 patients and dummy control units in 25 patients for 12 weeks. Radiographs were assessed blindly and independently by a radiologist and an orthopaedic surgeon. Statistical analysis showed the treatment groups to be comparable except in their age distribution, but age was not found to affect the outcome and the effect of treatment was consistent for each age group. The radiologist's assessment of the active group showed radiological union in five fractures, progress to union in five but no progress to union in 10. In the control group there was union in one fracture and progress towards union in one but no progress in 23. Using Fisher's exact test, the results were very significantly in favour of the active group (p = 0.002). The orthopaedic surgeon's assessment showed union in nine fractures and absence of union in 11 fractures in the active group. There was union in three fractures and absence of union in 22 fractures in the control group. These results were also significantly in favour of the active group (p = 0.02). It was concluded that pulsed electromagnetic fields significantly influence healing in tibial fractures with delayed union. Patients with tibial fractures which had remained un-united for at least 52 weeks were randomly allocated to either active or dummy pulsed magnetic field stimulators and treated in full leg plasters for 24 weeks with a non-weightbearing conservative regimen, as is usual with such techniques. Fractures in 5 of the 9 patients with working machines united and fractures in 5 of the 7 patients with dummy machines also united. These early results of this double-blind trial are compatible with a difference in success rate at 24 weeks on active treatment of + 33% to -61% (95% confidence limits) compared with the success rate on the dummy stimulators. The high proportion of fractures uniting in the control group suggests that conservative management of non-union is effective and this may explain much of the success attributed to pulsed magnetic field therapy. Electrical stimulation in the treatment of bony non-union has been used in different forms for many years. However, there is still a lot of uncertainty about its efficacy. We, therefore, undertook a prospective, randomised, double-blind trial to try and determine its effect. Over a period of 5 years, 34 consecutive patients with a tibial non-union met our "criteria for inclusion". Each patient had an oblique fibular osteotomy, followed by a unilateral external fixator. They were then randomly allocated one of two machines. Group 1, the active group, received electrical stimulation from an active machine. Group 2, the dummy group, had an identical machine but without any current passing through the active coils. They were then followed up for 6 months and evaluated clinically and radiologically for bony union. Unfortunately, there was by chance, an imbalance in smoking habit between the two groups. The union rate in the subgroup that smoked was 75% (6/8) in the active group as compared to 46% (6/13) in the dummy group. The active group of non-smokers had 100% (10/10) union rate, compared to 67% (2/3) in the dummy group. Overall 24 out of the 34 patients progressed to union. Out of 18, 16 (89%) in the active group showed bony union as compared to 8/16 (50%) in the dummy. There was, thus, a statistically significant positive association between tibial union and electrical stimulation (odds ratio 8, 95% CI: 1.5-41, P=0.02). Twenty-three patients who had an established non-union of a long bone were entered into a prospective, double-blind trial in which electrical capacitive coupling was used for treatment. Twenty-one patients completed the study: ten who were actively managed and eleven who were managed with a placebo unit. The non-union healed in six of the ten patients who had been managed actively but in none of the patients who had been managed with the placebo unit. This difference in the rates of healing between the actively managed and the placebo groups is highly significant (p = 0.004).
Though the available evidence suggests that electromagnetic field stimulation may offer some benefit in the treatment of delayed union and non-union of long bone fractures, it is inconclusive and insufficient to inform current practice. More definitive conclusions on treatment effect await further well-conducted randomised controlled trials.