Table 1 Summary of the characteristics of the included studies.
Study | N | Selected study arms | Co-intervention | Follow-up | IFC in intervention group | Appraised outcome measure | |
|---|---|---|---|---|---|---|---|
Protocol | IFC settings | ||||||
Quirk et al.16 | 26 | (1) Active IFC + exercises (2) Exercises‡ | Exercise program (twice/d for 4 wk) | 3–6 mo | 15 min/d 3 d/wk for 4 wk | Pulse frequency: 0–100 Hz for 10 min, 130 Hz for last 5 min Pulse width and amplitude: N/A Electrodes: Suction electrodes (placement N/A) | Overall clinical score |
Adedoyin et al.17 | 30 | (1) Active IFC + exercises (2) Sham IFC + exercises‡ | Dietary advice + Exercise program (twice/wk for 4 wk) | At treatment completion | 20 min/d 2 d/wk for 4 wk | Pulse frequency: AMF at 100 Hz for 15 min, 80 Hz for last 5 min Amplitude: Above sensory threshold Electrodes: 2 placed at latero-medial region, 2 placed at antero-posterior region | Pain (VAS) |
Adedoyin et al.18 | 31 | (1) Active IFC + exercises (2) Exercises‡ | Exercise program (twice/wk for 4 wk) | At treatment completion | 20 min/d 2 d/wk for 4 wk | Pulse frequency: Continuous 80 Hz Amplitude: Above sensory threshold with tingling sensation Electrodes: 2 placed longitudinally at each side of knee | Pain (VAS), function (WOMAC) |
Defrin et al.19 | 54 | (1) Active IFC (2) Sham IFC† | Nil | At treatment completion | 20 min/d 3 d/wk for 4 wk | Pulse frequency: Carrier at 4000 Hz and AMF at 30–60 Hz Amplitude: 30% above (noxious) or 30% below (innocuous) sensory threshold; sensation maintained by raising intensity in adjusted group Electrodes: 1 placed at lateral side of knee, 1 placed at medial side of knee | Pain (VAS), stiffness (VAS) |
Itoh et al.20 | 24 | (1) Active IFC (2) Control† (3) Active IFC + acupuncture (4) Acupuncture‡ | Control: Topical poultice if required Acupuncture: Six acupoints on affected knee (once/wk for 5 wk) | 10 wk | 15 min/d 1 d/wk for 5 wk | Pulse frequency: Carrier at 4000 Hz and 4122 Hz, AMF at 122 Hz Amplitude: 2–3 times above sensory threshold Electrodes: A 809-mm2 electrode placed at the most tender site, a 5688-mm2 electrode placed at its opposite side | Pain (VAS), function (WOMAC) |
Dyson21 | 24 | (1) Active IFC + exercises (2) Exercises‡ | Exercise program (twice/wk for 3 wk) | At treatment completion | 25 min/d 2 d/wk 3 wk | Pulse frequency: Carrier at 3850 Hz and AMF at 80–120 Hz Electrodes: 4 placed around symptomatic knee | Pain (VAS), function (WOMAC) |
Atamaz et al.22 | 66 | (1) Active IFC + exercises (2) Sham IFC + exercises‡ | Exercise program (3 d/wk for 3 wk) | 1, 3, and 6 mo | 20 min/d 5 d/wk 3 wk | Pulse frequency: Carrier at 4000 Hz and AMF at 100 Hz Amplitude: Tactile sensory threshold Electrodes: 2 placed at knee region | Pain (VAS), function (WOMAC), mobility (15-m walk test) |
Gundog et al.23 | 30 | (1) Active IFC (2) Sham IFC† | Nil | 1wk | 20 min/d 5 d/wk 3 wk | Pulse frequency: Carrier at 4000 Hz and AMF at 100 Hz Amplitude: Strong but comfortable level Electrodes: 2 placed laterally on the patella | Pain (VAS), function (WOMAC), mobility (15-m walk test), stiffness (WOMAC) |
de Paula Gomes et al.24 | 40 | (1) Active IFC + exercises (2) Sham IFC + exercises‡ | Exercise program (3 d/wk for 8 wk) | At treatment completion | 40 min/d 3 d/wk 8 wk | Pulse frequency: Carrier at 4000 Hz and AMF at 75 Hz Amplitude: Strong but comfortable level Electrodes: 4 placed around affected knee | Pain (VAS), function (WOMAC), stiffness (WOMAC) |
Alqualo-Costa et al.25 | 84 | (1) Active IFC + sham PBM (2) Sham IFC + sham PBM‡ (3) Active IFC + active PBM (4) Sham IFC + active PBM‡ | PBM: low-level laser, 27 J per session; average power, 40 mW; cross-sectional area, 0.5 cm2 | 3 and 6 mo | 30 min/d 3 d/wk 4 wk | Pulse frequency: Carrier at 4000 Hz and AMF at 50–100 Hz Amplitude: Strong level that is not painful Electrodes: 4 placed with quadripolur configuration to cover area of pain | Pain (VAS), function (WOMAC), mobility (timed up and go test) |
