| Study | Reason for exclusion |
|---|---|
| Barr 2004 | Less than 50% of patients diagnosed with osteoarthritis of the knee |
| Bernau 1981 | Not a randomised controlled trial, use of active control groups. Additional description: comparing diadynamic electrostimulation df, diadynamic electrostimulation cf and galvanic current |
| Burch 2008 | Use of active control group. Additional description: randomised controlled trial comparing interferential current stimulation followed by patterned muscle stimulation and low‐current transcutaneous electrical nerve stimulation (TENS). |
| Cauthen 1975 | Not concerning osteoarthritis |
| Commandre 1977 | No randomised controlled trial (review) |
| Cottingham 1985a | Not transcutaneous but subcutaneous application |
| Cottingham 1985b | Not transcutaneous but subcutaneous application. Abstract referring to same RCT as described in Cottingham 1985a. |
| Durmus 2005 | Use of active control group (exercise) |
| Gaines 2001 | Neuromuscular electrostimulation primarily aiming at muscle strengthening |
| Gaines 2004 | Neuromuscular electrostimulation primarily aiming at muscle strengthening |
| Gibson 1989 | Most likely not a randomised controlled trial; percutaneous electrostimulation primarily aiming at muscle strengthening |
| Godfrey 1979 | Faradic electrostimulation with parameters set to increase muscle strength and use of active control (exercise plus low intensity (sham) faradic electrostimulation) |
| Grigor'eva 1992 | No relevant pain or function outcomes |
| Guven 2003 | High voltage galvanic electrostimulation for muscle strengthening |
| Hamilton 1959 | Only 34% of patients suffered OA; use of active controls. Additional description: cross‐over design evaluating faradic electrostimulation. |
| Huang 2000 | TENS as part of a combined experimental intervention. Additional description design: 3 groups, Group A receiving auricular acupuncture, diet control and aerobic exercise, Group B like A with addition of TENS and ultrasound, Group C receiving TENS and ultrasound; unclear whether allocation was at random. |
| Jensen 1991 | Use of active control: high frequency TENS versus low frequency TENS |
| Kang 2007 | Percutaneous electrostimulation |
| Katsnelson 2004 | Electrode placement not involving knee innervation: transcranial electrostimulation |
| Komarova 1998 | Electrode placement not involving knee innervation: transcranial electrostimulation |
| Lewis 1984 | Cross‐over RCT reporting pooled results after completion of all phases. Contact established with Daniel and Beverly Lewis, who were unable to provide results for the first phase (before cross‐over) |
| Lewis 1985 | RCT reporting P values of effect only. Contact established with Daniel and Beverly Lewis, who could not provide any additional outcome data, nor could they indicate whether the design concerned a cross‐over or a parallel RCT |
| Lewis 1988 | Published abstract addressing the same cross‐over RCT reported by Lewis 1994 |
| Lewis 1994 | Cross‐over RCT reporting pooled results after completion of all phases. Contact established with Daniel and Beverly Lewis, who were unable to provide results for the first phase (before cross‐over) |
| Lone 2003 | Not a randomised controlled study. Additional description: before‐after study design that was incorrectly labelled as randomised study by original authors. |
| Lund 2005 | Not concerning osteoarthritis |
| Macchione 1995 | Not a randomised controlled trial (review) |
| Matti 1987 | Not concerning osteoarthritis, not a randomised clinical trial. Tetanus‐like faradisation electrostimulation with exercise after surgical removal of meniscus, primarily aiming at muscle enhancement. Active control with 10 Hz sinusoidal current application and exercise. |
| Miranda‐Filloy 2005 | Electrical muscle stimulation using sport400 (Complex), primarily aiming at muscle strengthening |
| Mont 2006 | Not a randomised clinical trial. Description: comparative study with historical control evaluating pulsed electrostimulation. |
| Oldham 1995 | Neuromuscular electrostimulation primarily aiming at muscle strengthening |
| Oldham 1997 | Electrostimulation primarily aiming at muscle strengthening |
| Oosterhof 2008 | Mixed population, only 4 out of 163 patients reported to have knee, hip or ankle OA |
| Paillard 2005 | Not concerning osteoarthritis (healthy volunteers) |
| Picaza 1975 | Not concerning osteoarthritis and not a randomised controlled trial |
| Salaj 2001 | Not a randomised controlled trial, combined multiple interventions in both interventions and control group |
| Salim 1996 | Not a randomised controlled trial (review) |
| Sluka 1998 | Animal study |
| Sok 2007 | Concerns chronic knee pain. First author was contacted by email to verify how many patients had osteoarthritis. No response received. Additional description: article in Korean, using a TENS device, abstract however suggests that parameters were set to strengthen muscles. |
| Svarcova 1988a | Use of active control groups. Additional description: controlled trial with groups receiving either galvanic electrostimulation or YES ultrasound or pulsed shortwaves. Within these groups, half of the patients received ibuprofen, half received placebo ibuprofen. It was unclear whether allocation was at random. |
| Svarcova 1988b | See Svarcova 1988a. Double publication of the same study, including the same number of patient and outcome data. |
| Svarcova 1990 | Use of active control group. Additional description: galvanic electrostimulation versus electroacupuncture. |
| Talbot 2003 | Neuromuscular electrostimulation primarily aiming at muscle strengthening |
| Tam 2004 | No relevant pain or function outcomes used |
| Taylor 1981 | Incomplete presentation of data. Additional description: cross‐over randomised clinical trial presenting pooled results only. Contact established with Mark Hallett, who was unable to provide data concerning the first phase, before cross‐over. We were unable to contact the other authors. |
| Tulgar 1991 | Not concerning osteoarthritis |
| Volklein 1990 | Use of active control group. Additional description: random allocation of patients to 4 different types of diadynamic current. |
| Weiner 2007 | Not transcutaneous but periosteal (needle) application |
| Zivkovic 2005 | Use of active control group. Additional description: the combination of low‐energy laser, pulsed electromagnetic field and kinesitherapy was compared to the combination of electrotherapy, pulsed electromagnetic field and kinesitherapy. |
OA = osteoarthritis RCT = randomised controlled trial TENS = transcutaneous electrical nerve stimulation