Extracorporeal shockwave therapy in osteonecrosis of femoral head: A systematic review of now available clinical evidences

Zhang, Qingyu; Liu, Lihua; Sun, Wei; Gao, Fuqiang; Cheng, Liming; Li, Zirong

The exact mechanism of ESWT in the treatment of ONFH is still controversial. High-energy extracorporeal shockwave travels through soft tissue and the change of impedance between soft tissue and bone interface results in energy deposition. This energy deposition of high acoustic waves may explain part of the therapeutic effect of extracorporeal shockwave. Meanwhile, extracorporeal shockwave has the ability to propagate through necrotic femoral hips and at the depth of 10 mm of bone, a pressure loss of 50% of shockwave was observed. [30] One hypothesis is that ESWT could induce microfracture to accelerate bone healing and increase pain threshold. [10] Higher expression level of bone morphogenic protein (BMP)-2, vessel endothelial growth factor (VEGF), alkaline phosphatase, Runt-related transcription factor 2 (RUNX2) and osteocalcin mRNA in marrow stromal cells as well as more mature mineralized nodules were demonstrated in ESWT group compared with control group, in which nitric oxide acted as the mediator. [31] One study showed increased osteogenesis and angiogenesis as well as bone remodeling of diseased hips after ESWT, indicating a regeneration effect. [17, 32, 33] In experiments with rabbit model, the expression of VEGF, BMP-2 and corresponding mRNA in subchondral bone of necrotic femoral heads was significantly up-regulated, which was consistent with the results in human samples. [34, 35] Durst et al reported that a woman with calcific tendinitis received high-energy extracorporeal shockwave lithotripsy, and about 3 and a half years later she was diagnosed with osteonecrosis of humeral head. [36] Liu et al [37] presented another similar case report in which the onset of osteonecrosis of humeral head occurred only 3 months after ESWT. It is supposed that the high dose of extracorporeal shockwave and relatively small diameter of anterior humeral circumflex in 2 case reports might explain these complications. Though no evident complications of ESWT for treating ONFH was revealed, deterioration of lesions did be observed in some cases. Therefore, before starting ESWT, important arteries and nerves ought to be located with ultrasonography to avoid any possible damage. It is believed that radial ESWT has no need for location in advance but collection of high-quality data is necessary to testify this assumption.