gms | German Medical Science

Objectives: For almost 50 years electric and electromagnetic fields (EMF) have been reported to improve bone healing after injuries and surgical procedures. Despite the overall positive effects on osseous consolidation this technology remained a niche application. Recently, we identified a specific extremely low-frequency pulsed electromagnetic field (ELF-PEMF) that supports osteoblast function without affecting osteoclast function in vitro. Aiming for a clinical translation, this study investigates the effect of this specific ELF-PEMF (16 Hz) on osseous consolidation after high tibial osteotomy (HTO).

Methods: Randomized, placebo-controlled, double-blind clinical trial. Level of evidence 1 (DRKS-ID: DRKS00008870). 75 patients undergoing a single HTO were randomized to receive either ELF-PEMF (N = 37) or a placebo treatment (N = 38). ELF-PEMF or placebo were applied by optically identical external devices (Somagen®, Sachtleben GmbH, Hamburg / certified for medical use in Europe) 7 minutes per day for 30 days following surgery. Osseous consolidation was evaluated by post-surgical (7 and 14 weeks) X-rays. Serum levels of BAP, TRAP5b, TNF-α, IL-6, MCP-1, and IL-13 were determined by ELISA. Unblinding was performed after all data were collected. Data sets were compared by two-tailed Mann-Whitney U-test or Kruskal Wallis H-test. Analysis was reviewed by an independent statistician. p < 0.05 at an α = 0.05 was taken as minimum level of significance.

Results and conclusion: Data of 74 patients were investigated, as one patient (placebo group) did not complete post-surgical care. Both the patients' documentation and the readout of the devices showed an excellent compliance among the study patients. After unblinding, study cohorts (ELF-PEMF and placebo group) did not differ in mean age (53.49±0.81 a), BMI (29.9 ± 0.6 kg/m2), number of co-morbidities (2.65 ± 0.18), nutritional status, or pre-surgical blood values. Merely, there was a higher frequency of females in the ELF-PEMF group (43.2%) than in the placebo group (21.6%, p = 0.081). X-ray images revealed a faster osseous consolidation in the ELF-PEMF group (4.38 ± 0.18 %/week) compared to the placebo group (3.53 ± 0.22 %/week). This effect was independent of the gender or BMI, but became more pronounced with increasing age of the patients (> 50 a (N = 24 & 27): 4.84 ± 0.42 %/week vs. 3.53 ± 0.21 %/week, p = 0.023). Post-surgically increased BAP serum levels in the ELF-PEMF group (21.3 ± 1.3 µg/l vs. 19.1 ± 1.0 µg/l, p = 0.029) supported this finding. Other serum levels obtained were comparable between ELF-PEMF and placebo group, suggesting no adverse effects of the ELF-PEMF treatment.

This specific ELF-PEMF therapy improves osseous consolidation after HTO significantly in elderly patients (> 50 years). With the very good acceptance and compliance, the ELF-PEMF treatment represents an interesting adjunct to conventional therapy supporting osseous consolidation in elderly patients.