Sunday, May 21, 2023

Do Orthotics Reduce Kneecap Loads In People With Knee Pain?

Many of our patients wear insoles (or orthotics) as they have been told that it 'corrects' their flat feet while helping to reduce excessive forces on their patellofemoral (kneecap) joint. This then helps to prevent kneecap pain.

Customed made orthotic
Well, if you have been told (by your health professional) that you need insoles/ orthotics for the same reasons, now you can tell them that this latest published systematic review/ meta analyses from the BJSM suggests otherwise. This is a very important study since kneecap pain is very commonly seen in in our clinics (and many others) affecting both the young adolescents and older adults. 

The authors identified 33 eligible studies and did 3 different comparisons during walking and running combined. Using insoles/ orthotics with medial (arch) support versus no insoles, minimalist shoes versus conventional footwear and lastly rocker versus non-rocker footwear.

Arch supports
Analyses by the authors showed that insoles/ orthotics that support your medial arches DID NOT alter kneecap loads during walking or running. This questions results from previous research that suggests the pain reducing effects of insoles/ orthotics. The reduction in pain may have been due to other influences and not the reduction in kneecap loads.

Results also show that mimimalist type footwear reduced peak kneecap loads when compared to conventional footwear during walking and running combined. This systematic review demonstrated an average 9.5 percent reduction in kneecap load in minimalist type footwear compared to conventional footwear over a run of just 1 km. This translates to 1,462 kg for an 80 kg person. This is clinically relevant considering the cumulative load reduction that can occur over numerous loading cycles during running.

I've written about this known fact many times over the years. Using results from Daniel Liberman's study (2010), runners who land correctly in their running technique will have benefits as impact is a lot less (even less than landing on your heels with cushioned shoes on).  If you land wrongly (with minimalist type shoes) the impact is 7 times greater thus greatly increasing the chance of injury. See picture below.

Because kneecap loads are reduced, they are transferred to the ankle and foot bones leading to fractures in the foot bones especially when you do too much too soon. Hence, correct technique and patience is crucial using minimalist type footwear. This is why many podiatrists say minimalist type footwear is not good (for you) since they cause foot  and metatarsal fractures, but bear in mind podiatrists also cannot sell you orthortics to place in your minimalist type footwear. 

You have also never seen Kipchoge or any elite marathoners wear these minimalist type shoes in a race. The body's muscles will not be able handle absorbing the load (while wearing minimalist type shoes) while running at the high intensities at which these races are contested.  They are good for training definitely, but not for racing, especially if you are not patient enough to get used to them. 

Evidence regarding the effect of rocker-soled shoes (see below) during walking and running were uncertain due to limited studies.

Take home message from the researchers is that minimalist type footwear reduces kneecap loads compared to conventional footwear in people with or without kneecap pain during running. 

Insoles/ orthotics that support the arches do not alter kneecap load during walking or running. Now you know for sure.


Liberman DE, Venkadesan M et al (2010). Foot Strike Patterns and Collision Forces in Habitually Barefoot Versus Shod Runners. Nature. Jan 463(7280): 531-535.

Kayll SA, Hinman RS, Bryant AL et al (2023). D Biomechanical Foot-based Interventions Reduce Patellofemoral Joint Loads In Adults With And Without Patellofemoral Pain Or Osteoarthritis? A Systematic Review And Meta-analysis. BJSM. DOI: 10.1136/bjsports-2022-106542

MBT rocker-sole shoes
*Thanks to Hui Meng for getting me the article

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