Correa, 2016¹⁴⁴

3 months

Duration of pain: Mean 95.3 to 99.4 months

Fair

All groups received: 3 sessions/week for 4 weeks (12 total sessions)

A. 1 kHz Interferential current (n=50)

B. 4 kHz Interferential current (n=50)

C. Placebo interferential current (n=50)

A vs. B vs. C

Age: 51 vs. 54 vs. 49 years

Female: 70% vs. 80% vs. 80%

Baseline RDQ (0-24): 13.3 vs. 14.2 vs. 15.1

Baseline NRS pain score in last 7 days (0-10): 7.5 vs. 7.5 vs. 7.4

A vs. C

3 months

RDQ: 9.0 vs. 10.3, adjusted difference 0.3 (CI unclear) ^b

NRS at rest: 4.6 vs. 4.7, adjusted difference 0.4 (CI unclear)

B vs. C

3 months

RDQ: 9.3 vs. 10.3, adjusted difference 0.2 (CI unclear) ^b

NRS at rest: 4.4 vs. 4.7, adjusted difference 0.2 (CI unclear)

A vs. C

3 months

GPE: 1.7 (3.1) vs. 1.6 (3.1), adjusted difference 0.6 (CI unclear)

Mean number of times that patients needed to take pain medication between treatment sessions: 12.5 (6.0) vs. 30.7 (15.2), p=0.01; difference –18.2 (95% CI –22.79 to –13.61)

B vs. C

3 months

GPE: 1.8 (3.0) vs. 1.6 (3.1), adjusted difference 0.5 (CI unclear)

Mean number of times that patients needed to take pain medication between treatment sessions: 13.1 (6.9) vs. 30.7 (15.2), p=0.014; difference −17.6 (95% CI −22.28 to −12.92)