Results of the search

The search strategy (Appendix 1, completed May 2014) yielded a total of 217 records from the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE (current contents, HealthSTAR). The search resulted in identification of the citations of 25 reports of potentially eligible studies, for which (where possible) full reports were obtained. We included a total of 13 studies in the review. We needed the opinion of a third review author once (Shakoor 2008) before we could come to a final decision.

Overall, this review consists of 13 included studies, 12 excluded studies, no ongoing studies and no studies awaiting classification (Figure 1). We checked the reference lists of the included studies but identified no further studies.

Figure 1

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Figure 1 Flow diagram of the study according to the PRISMA statement.

Included studies

We included 13 studies described in 17 publications involving 1356 participants; we included four studies in the first version, added three studies in the first update and added six more studies in this second update. We have described these studies in detail in the Characteristics of included studies table.

One group (Maillefert 2001) published separately six‐month and two‐year results, another group presented separately six‐month and one‐year results (Erhart‐Hledik 2012) and another group (Toda 2001) published separately eight‐week, six‐month and two‐year results. We have described the 13 selected studies in detail in the Characteristics of included studies table. Four studies (Brouwer 2006; Kirkley 1999; Müller‐Rath 2011; Sattari 2011) investigated knee braces, and eight studies (Barrios 2009; Bennell 2011; Erhart‐Hledik 2012; Maillefert 2001; Sattari 2011; Toda 2001; Toda 2002; Toda 2008) examined foot/ankle orthoses for medial compartment OA of the knee. Two studies (Raaij van 2010; Sattari 2011) compared a knee brace with a foot orthosis. Only two studies (Brouwer 2006; Rodriques 2008) also assessed the benefits of a brace or a foot/ankle orthosis for treating lateral compartment osteoarthritis. No studies assessed the benefits of a brace or an insole for general OA of the knee. In 12 studies the degree of OA was scored according to Kellgren & Lawrence (K&L) (Kellgren 1957), and in one study (Brouwer 2006) according to Ahlback (Ahlback 1968). In two studies osteoarthritic changes were also checked on magnetic resonance imaging (MRI) (Bennell 2011; Erhart‐Hledik 2012). The mean number of participants in the 13 studies was 103 (range 30‐207). Mean participant age was 62 years (range 48‐65 years). In two trials, all participants were females (Toda 2001; Toda 2002). (See also Characteristics of included studies.)

Barrios 2009 published an RCT of 66 participants with symptomatic medial knee OA (K&L grade II‐IV). In this RCT, a treatment group ‐ a full‐length (9.1 degrees (standard deviation (SD) 3.9 degrees)) laterally wedged insole into the shoe (n = 35) ‐ had been compared with a control group ‐ a non‐custom neutral insole into the shoe (n = 31). Block randomisation was performed based on OA grade, gender and age (older or younger than 55 years). Allocation was done by an administrative assistant who was unaware of the methods used. The study included 29 males and 37 females with medial tibiofemoral OA (scored according to K&L), mean age of 62.4 years and mean BMI of 33.0 kg/m². Baseline characteristics (gender, BMI, OA grade) did not differ between groups. A total of 20/35 (57%) participants remained in the treatment group and 25/31 (81%) in the control group at final one‐year follow‐up. The primary outcome measure was mean Western Ontario‐McMaster Osteoarthritis Scale (WOMAC) subscore (100‐0); secondary outcomes included a six‐minute walking test and a stair negotiation test. Mean and P values were presented, but SD values were missing.

Bennell 2011 reported a double‐blinded RCT of 200 participants with mild to moderately severe medial knee OA and radiological evidence of osteophytes in the medial compartment or medial joint space narrowing on an x‐ray film. In this RCT, a treatment group ‐ a full‐length five‐degree laterally wedged insole (n = 103) ‐ was compared with a control group ‐ a flat insole (n = 97). The randomisation procedure consisted of a computer‐generated block method using sealed envelopes. Participants included 82 men and 118 women; mean age was 64 years. Mean BMI was 29.2. The degree of radiological OA was scored according to K&L on posteroanterior radiographs and on MRI. Mean varus alignment was 181 degrees. Follow‐up was 12 months. Eleven participants in the intervention group and ten in the control group were lost to follow‐up.

Brouwer 2006 published a multi‐centre RCT of 117 participants with symptomatic unicompartmental knee OA (Ahlback > 0). In this RCT, investigators studied the additive effect of a brace intended to reduce load in the conservative treatment of unicompartmental (medial or lateral) knee OA. A total of 60 participants were included in the intervention group (brace and standard conservative treatment) and 57 in the control group (standard conservative treatment alone). The brace is available for right and left knees in four sizes. The brace consists of a thigh shell and a calf shell (both of carbon fibre) connected by titanium hinges on the medial and lateral sides. The adjustable side bar on the medial side of the brace provides valgus (1‐12.5 degrees) with medial unloading, or varus (1‐10 degrees) with lateral unloading. The randomisation procedure consisted of a computer‐generated block method using sealed envelopes. Participants included 59 men and 58 women. Mean age was 59 years. Mean BMI was 29. The degree of OA was scored according to Ahlback. Patients with an Ahlback score of I or II were included. Mean varus alignment was nine degrees. Mean valgus alignment was six degrees (hip‐knee‐ankle (HKA) angle). Follow‐up was 12 months. Four participants in the control group were lost to follow‐up.

Erhart‐Hledik 2012 reported an RCT of 79 participants with symptomatic medial knee OA and osteoarthritic changes on MRI. In this study a treatment group ‐ variable‐stiffness shoe (n = 40) ‐ was compared with a control group ‐ constant stiffness shoe (n = 39). The randomisation procedure was not described. Participants included 42 men and 37 women. Mean age was 60 years. Mean BMI was 27.7. The degree of radiological OA was scored on MRI at baseline. Follow‐up was 12 months. Eight participants in the intervention group and 13 in the control group were lost to follow‐up.

Kirkley 1999 reported an RCT comparing (1) a valgus brace with medical treatment (n = 41); (2) a neoprene sleeve with medical treatment (n = 36); and (3) a control (i.e. medical treatment only) (n = 33). Individuals with OA of the knee and pain localised to the medial compartment were included in this trial. The valgus brace was custom made and consisted of a polyethylene thigh shell connected to a polyethylene calf shell through a polyaxial hinge on the medial side, which allowed application of four degrees valgus. The randomisation procedure consisted of a computer‐generated block method using sealed envelopes. Follow‐up was six months. Nine participants were lost to follow‐up (neoprene sleeve ‐ two/control ‐ seven). Participants included 79 men and 31 women. Mean age was 59 years. Mean varus alignment was nine degrees. Degree of OA of the knee was described only in the unloader brace group. Outcome data were presented as means and P values but without standard deviations; this made pooling impossible. Additional information was obtained from The Kirkley Research Group, but this information was not sufficient for analysis.

Maillefert 2001 presented an RCT of 156 participants with symptomatic medial knee OA (K&L > I). Laterally wedged insoles (n = 82) were compared with neutral insoles (n = 74). Both insoles were made of Ledos material, which consists of pure rubber with cork powder. The laterally elevated insoles were individually modelled, with elevation depending on static pedometer evaluation. The randomisation procedure was not described. Participants included 41 men and 108 women. Mean age was 65 years. Mean BMI was 29. Degree of varus alignment was not measured. After six months' follow‐up, nine participants (four from the wedged insole group) were lost to follow‐up. Two‐year follow‐up results were provided in 2004 (Pham 2004). A total of 106 participants completed the two‐year follow‐up: neutrally wedged insole (n = 51) versus laterally wedged insole (n = 55).

Müller‐Rath 2011 reported a non‐blinded RCT of 33 participants with symptomatic medial knee OA with a minimum of grade II according to the radiographic classification of K&L. Two treatment groups were included: a valgus knee brace (n = 13) and an elastic knee bandage (n = 10). The control group consisted of untreated individuals (n = 10). The randomisation procedure was not described. Participants included 24 men and nine women; mean age was 53.2 years. Mean BMI was 27.2. Mean alignment was 189 degrees of varus femoro‐tibial angle (FTA). The number of participants lost to follow‐up was not reported.

Raaij van 2010 reported a non‐blinded RCT of 91 participants with symptomatic medial knee OA (K&L ≥ I). Participants were block‐randomised to treatment with a 10‐mm laterally full‐length wedged insole (index group, n = 45) or a valgus brace (control group, n = 46). Baseline characteristics were similar regarding mean age (55 years), mean BMI (29 kg/m²), medial and lateral OA grades, analgesic use, mean VAS pain score (5.6 (0‐10 scale)) and mean WOMAC function (47 (0‐100 scale)). Gender differed statistically significantly (index group 65% female vs control group 35% female). At six months, a non‐blinded investigator assessed VAS and WOMAC scores as well as varus alignment correction in the frontal plane using the HKA angle on standardised whole leg films.

Rodriques 2008 randomly assigned 30 consecutive women with bilateral valgus deformity knee OA to two groups: medial insole (insoles with 8‐mm medial elevation at the rearfoot (n = 16)) and neutral insoles (similar insoles without elevation (n = 14)). Both groups also wore ankle supports. The demographic features of both groups were similar regarding mean age (62 years), mean BMI (30 kg/m²), mean disease duration (five years), radiographic osteoarthritis severity (K&L), race distribution and sedentary habits. A blinded examiner assessed VAS, Lequesne and WOMAC scores, along with femorotibial, talocalcaneal and talar tilt angles at baseline and after eight weeks.

Sattari 2011 reported an RCT of 60 participants with knee pain, genu varum and moderate to severe medial knee OA (K&L grade III or IV). Investigators included two treatment groups: a custom‐molded valgus stress knee support (n = 20) and a 1/4‐inch laterally wedged insole (n = 20). The control group (n = 20) received only general management that was universally applied to all three groups, consisting of activity modification, heating agents, straight leg raising, isometric quadriceps home exercises and analgesic use, when needed. The randomisation procedure was computer‐generated. Participants included 22 men and 38 women. Mean age was 48 years. Mean VAS pain score was 6.9. The degree of radiological OA was scored according to K&L. Follow‐up was nine months. Five participants were lost to follow‐up.

Toda 2001 published a prospective trial comparing an elastic subtalar strapped insole (n = 46) versus a traditional lateral wedge insole (n = 44). This study included individuals with symptomatic medial knee OA (K&L II‐IV). The wedge of the strapped insole was made from urethane with elevation of 6.35 mm strapped to an ankle sprain supporter. The traditional insole was a lateral rubber heel wedge with elevation of 6.35 mm. Quasi‐randomisation was performed according to birth date. All participants were female. Mean age was 65 and mean BMI was 25. Follow‐up was eight weeks, and no participant was lost to follow‐up. Standing radiographs of participants with and without their respective insoles were taken before entry into the eight‐week study. Degree of varus was 181 degrees FTA. Six‐month results were published in 2004. A total of 61 participants completed the six‐month follow‐up: subtalar strapped insole (n = 29) versus traditional laterally wedged insole (n = 32). Two‐year results were published in 2006. Only 42 participants completed the two‐year follow‐up: subtalar strapped insole (n = 21) versus traditional laterally wedged insole (n = 21). Analysis was performed without an intention‐to‐treat approach. All results were presented in the original articles as pre/post analysis, not as between‐group differences (Toda 2001). However, for both the original review and the updated review, the study author was contacted for more information; he sent the missing information on between‐group analysis of FTA, VAS and Lequesne index scores.

Toda 2002 published a second trial comparing a subtalar strapped insole (n = 42) with a sock‐type ankle supporter (n = 46). Individuals with symptomatic medial knee OA were included in this trial (K&L II‐IV). The wedge of the strapped insole was made from urethane with elevation of 6.35 mm strapped to an ankle sprain supporter. The sock‐type ankle support extended from malleoli to metatarsals and consisted of a lateral wedged heel insole with elevation of 6.35 mm. The trial took place in the same year (2000) as the first study. The quasi‐randomisation procedure was performed according to birth date. All participants were female. Mean age was 65 and mean BMI was 25. Degree of varus was 181 degrees (FTA). Follow‐up was eight weeks, and no participant was lost to follow‐up. Results were presented as pre/post analysis, not as between‐group differences. Second, the Lequesne index was presented graphically and no exact numbers were given. However, the study author was contacted for more information again, and he provided the missing information on between‐group analysis of the Lequesne index.

Toda 2008 published a third RCT of 227 participants with symptomatic medial knee OA (K&L I‐IV). In this study a placebo ‐ a neutral wedged insole into shoes (n = 45) ‐ was compared with four interventions ‐ a wedged insole with shoes (n = 45), a sock‐type ankle supporter with a wedged insole without shoes (n = 46), a subtalar strapped insole with shoes (n = 45) and a subtalar strapped insole without shoes (n = 46). The randomisation procedure consisted of a computer‐generated block method using sealed envelopes. Baseline characteristics and outcomes were presented only for the 207 participants who completed the 12‐week follow‐up. A total of 20 of 227 participants did not complete the study, which included 24 men and 183 women. Mean age was 65 years. Mean BMI was 25. Degree of OA was scored according to K&L. Degree of varus was 181 degrees (FTA). Most results were presented as pre/post analysis, and only intake of non‐steroidal anti‐inflammatory drugs (NSAIDs) was compared between placebo and different interventions.

Outcome measures included function scores, VAS scores (pain), analgesic/NSAID intake, walking distance, WOMAC scores (pain, function and stiffness), Hospital for Special Surgery knee scores (HSS; function), McMaster Toronto Arthritis score (MACTAR; function), Lequesne index (pain and function), degree of OA (Ahlback and K&L), global patient assessment, quality of life (EQ‐5D; a measure of health status), leg alignment (HKA angle; FTA), compliance and side effects.

Excluded studies

After retrieving the full text for final assessment, the review authors excluded 12 studies (Baker 2007; Birmingham 2001; Horlick 1993; Hunter 2012; Katsuragawa 1999; Kuroyanagi 2007; Matsuno 1997; Rooser 1988; Sasaki 1987; Shakoor 2008; Toda 2002b; Tohyama 1991): two studies (Sasaki 1987; Tohyama 1991) because of a retrospective design, four studies because of a cross‐over design (Baker 2007; Hunter 2012; Kuroyanagi 2007; Shakoor 2008), four studies because of lack of a control group (Birmingham 2001; Horlick 1993; Katsuragawa 1999; Matsuno 1997) and two studies (Rooser 1988; Toda 2002b) because investigators did not report the targeted outcome measure.

Allocation

Randomisation was performed in all studies. However in four studies, the procedure was not clearly described (Maillefert 2001; Müller‐Rath 2011; Rodriques 2008; Sattari 2011). In the other nine studies, the randomised sequence was adequately generated and clearly described (Barrios 2009; Bennell 2011; Brouwer 2006; Erhart‐Hledik 2012; Kirkley 1999; Raaij van 2010; Toda 2001; Toda 2002; Toda 2008). In seven studies, randomisation and concealment of allocations before assignment were adequately generated (Barrios 2009; Bennell 2011; Brouwer 2006; Erhart‐Hledik 2012; Kirkley 1999; Raaij van 2010; Toda 2008).

Blinding

In many studies, blinding procedures for treatment providers, participants and outcome assessors were insufficient. In most trials, blinding procedures for outcome assessors, treatment providers and participants were scored as 'high risk'. In five studies at least one of the outcome assessors was blinded (Bennell 2011; Erhart‐Hledik 2012; Rodriques 2008; Toda 2002; Toda 2008), and in only three of these studies, care providers and participants were also blinded (Bennell 2011; Erhart‐Hledik 2012; Rodriques 2008).

Incomplete outcome data

In six studies, incomplete outcome data were not adequately addressed. These studies with drop‐outs did not include an intention‐to‐treat analysis (Kirkley 1999; Müller‐Rath 2011; Sattari 2011; Toda 2001; Toda 2002; Toda 2008).

Selective reporting

In most studies, the selective outcome reporting item was unclear because no study protocol was provided (Kirkley 1999; Müller‐Rath 2011; Sattari 2011; Toda 2001; Toda 2002; Toda 2008).

Valgus knee brace versus no treatment

Four studies described the results of knee braces versus no treatment in OA of the knee (Brouwer 2006; Kirkley 1999; Müller‐Rath 2011; Sattari 2011).

Foot/Ankle orthosis

Four studies (Barrios 2009; Bennell 2011; Maillefert 2001; Sattari 2011) described the results of a foot/ankle orthosis for medial compartment OA of the knee (foot/ankle orthosis vs no treatment or a neutral insole) (see also summary of findings Table 3).

Knee brace versus laterally wedged insole

Two studies (Raaij van 2010; Sattari 2011) described the results when a valgus knee brace versus a laterally wedged insole was used for medial compartment OA of the knee (see also summary of findings Table 4).