Marc Darrow, MD, JD. Joint Rehab Los Angeles
A February 2021 study (1) looked for the possible causes of chronic plantar fasciitis pain. The researchers of this study noted that “The lack of agreement on plantar fasciitis etiology makes treatment challenging and highlights the importance of understanding risk factors for preventive efforts.” What they recommended was that focus on body mass and weight and the load on the force-absorbing plantar surface structures may be a good starting point in the prevention and treatment of active individuals with plantar fasciitis.
This should be considered as more than passing advice from these researchers. Carrying extra weight, along with the obvious health risks it brings with it a suppressed immune system and a more challenging healing to an injury. This is highlighted by the findings of a February 2020 study (2) comparing PRP and cortisone treatments. In this research the cortisone injections provided more relief to obese patients than the PRP did. Let’ examine the study:
- The researchers investigated the efficacy of local injection of platelet-rich plasma (PRP) compared with the conventional method of local corticosteroid injection in obese patients who were resistant to other nonsurgical treatments.
- In this single-blind, randomized clinical trial, 32 obese patients with chronic plantar heel pain were randomly allocated to 2 groups of 16 participants each.
- In 1 group, 40 mg of dimethylprednisolone was injected once into the painful heel, whereas the other group received 3 separate injections of PRP, with each injection administered 1 week apart.
- The groups were compared at baseline and at 24 weeks after the injection, or course of injections, was administered.
- Morning pain, and foot function index were not statistically significantly different between the groups at baseline; however, at 24 weeks after the treatment, final pain and morning pain scores were statistically significantly better in the corticosteroid group. In obese patients with plantar fasciitis, injection with corticosteroid was more effective than PRP at reducing pain and improving function.
One way to look at this study is to think that the PRP is not working as well as the cortisone because the immune system in the obese patient is compromised. The inability of the body to heal would be considered troubling for some.
A September 2020 study (3) found that “people with plantar heel pain who use foot orthoses experience reduced foot pain if they have greater ankle dorsiflexion (range of motion) and lower BMI (body mass index), while they experience improved foot function (as well) if they have lower fear-avoidance beliefs and lower BMI.”
A January 2024 paper (4) assessed the effects of plantar fascia release and the use of foot orthoses on the medial longitudinal arch of the foot. This was a cadaver study. A cross-sectional study was designed (20 body-donors). Anthropometric measurements of the foot, foot posture index and the windlass test and force (toe extension when weight is applied) were measured in different conditions: unloaded, loaded position, with foot orthoses, after a 25% plantar fascia release and after a 50% release. The results indicate that the presence of foot orthoses leads to a significant increase in arch height compared to other conditions. Furthermore, when plantar fascia release is performed, the arch does not exhibit any signs of collapse.
More reading
References
1 Hamstra-Wright KL, Huxel Bliven KC, Bay RC, Aydemir B. Risk Factors for Plantar Fasciitis in Physically Active Individuals: A Systematic Review and Meta-analysis. Sports Health. 2021 Feb 3:1941738120970976.
2 Tabrizi A, Dindarian S, Mohammadi S. The Effect of Corticosteroid Local Injection Versus Platelet-Rich Plasma for the Treatment of Plantar Fasciitis in Obese Patients: A Single-Blind, Randomized Clinical Trial. The Journal of Foot and Ankle Surgery. 2020 Jan 1;59(1):64-8.
3 Whittaker GA, Landorf KB, Munteanu SE, Menz HB. Predictors of response to foot orthoses and corticosteroid injection for plantar heel pain. Journal of Foot and Ankle Research. 2020 Dec;13(1):1-9.
4 Rodríguez-Sanz J, Roche-Seruendo LE, López-de-Celis C, Canet-Vintró M, Ordoyo-Martin J, Fernández-Gibello A, Labata-Lezaun N, Pérez-Bellmunt A. Effects of plantar fascia release and the use of foot orthoses affect biomechanics of the medial longitudinal arch of the foot. A cadaveric study. American Journal of Physical Medicine & Rehabilitation. 2024 Apr 16:10-97.