OA is a multifactorial disease classified as primary or secondary based on the recognized causative factors (Martel-Pelletier et al. 2016). Age and obesity are considered the most prominent, however, trauma, surgery or congenital abnormalities in joints are few examples of risk factors.
Okuno et al. postulated embolization of the inflammatory regions of joints causing pain (Okuno et al. 2015). The technique was already been performed in the treatment of plantar fasciitis, and to treat synovitis of knee and upper limb joints with excellent short and middle-term results (Okuno et al. 2015; Okuno et al. 2017a; Hwang et al. 2018; Okuno et al. 2017b).
The rationale of the technique comprises in understanding that the pathological mechanisms of OA involves pro-inflammatory leukins, such as IL-1β, IL-6 and IL-8 and tumor necrosis factor (TNF) α. These inflammatory mediators, in addition to mechanical and oxidative stress, cooperate to compromise the function and viability of chondrocytes, reprogramming them to undergo an hypertrophic differentiation, making them more sensitive to the effects of pro-inflammatory and pro-catabolic mediators (Mobasheri and Batt 2016).
This pro-inflammatory state of the joint activates innumerous receptors, and the vascular endothelial growth factor (VEGF) represents the major rate-limiting step during of the process from the angiogenic process. In resume, chronic inflammation and angiogenesis are reciprocal cause and effect factors that aggravate and intensify each other (Costa et al. 2007). The vicious circle is deteriorated by the genesis of abnormal enervation. Ashraf et al. found in postmortem knees with high tibiofemoral chondropathy an increased density of blood vessels near the fibrocartilage junction, in association with a great number of perivascular sensory nerves, postulating that this association is a possible mechanism of pain in OA (Ashraf et al. 2011).
To our knowledge, this is the first publication of hip inflammatory embolization. There are few technical points in this case that must be highlighted: first, it was not found the inflammatory “tumoral” blush seen in other publications. The embolization was performed based only in the branches that the patient referred pain during selective angiography and the identification of small corkscrew arteries at that area. This may be due to the small focal area of hipersignal found on MRI. Despite performing the procedure with technical success, it may not be recommend embolization without identification of the blush, since no-target embolization can happen, specially if superselective catheterization is not achieved. Second, despite there are reports of use of microspheres in this technique (Okuno et al. 2017a), there is a risk of hip osteonecrosis there is so far unknown and must be considered, particularly if non-target embolization of the proximal branches of the lateral femoral circumflex artery occur. Imipenen/cilastatin was not used in this first case due to the absent of the authorization of our institution for the arterial use of the drug. In the following cases (unpublished data) the authors have shifted to its use, since it was demonstrated by Woodhams et al. that this embolic agent may reduce the risk of ischemia (Woodhams et al. 2013). Third, the procedure was performed with local anesthesia. Collaboration of the patient, reporting her symptoms, was paramount for the technical success. Despite the small stature of our patients (149 cm) this was not possible to perform the procedure using radial access since a very distal super-selective catheterization is necessary. In this situation, contralateral approach is an option.