gold standard for preserving the femoral head. However, the potential risk included infections and immune response, and reports unsatisfactory results [8]. Recently, ESWT was reported effective by researchers in the treatment of ONFH [9–11]. This article describes a new effective and noninvasive method of ESWT for the treatment of ONFH.
ESWT for ONFH
Researchers reported that focused ESWT is effective in the treatment of ONFH [9–12]. However, the exact mechanism of ESWT in ONFH is still unknown. In 2001, Ludwig et al. [9] first reported ESWT treatment in 22 patients with ONFH of ACRO classification from stages 1–3 and were followed up for 1 year. The patients showed significant improvement in the visual analogue pain score, which decreased from 8.5 to 1.2. Harris hip score increased from 43.3 to 92 and the lesion size decreased or healed in 10 of 14 successfully treated patients. The therapeutic success rate was noticed in 14 patients, and 4 patients showed complete healing on MRI. Wang et al. [10] were the first to report that ESWT treated patients with ONFH by using FDA-approved machine OssaTron in Taiwan in 2005 (Fig. 1). They compared ESWT treatment in 23 patients (29 hips) with 25 patients (29 hips) receiving core decompression with nonvascularized fibular grafting with early stages of ONFH. The results showed significant improvement in pain and Harris hip scores (p < 0.001). There was a trend of reduction in the lesion size of ESWT group as compared to core decompression with fibular graft side on average follow-up of 25 months. In 2009, Chen et al. [13] compared the functional outcomes of ESWT on one side and total hip arthroplasty (THA) on the other hip in 17 patients with bilateral hip necrosis. The pain score and Harris hip score showed significant improvements after treatment (p < 0.001). A significant difference in the levels of improvement was observed between the 2 sides, with the difference favoring the ESWT side (p < 0.001). The results showed that 13 patients rated ESWT better than THA and only 4 patients reported comparable results between THA and ESWT and no one scored that THA was better than ESWT. At 1-year follow-up, of 36 patients with 42 hips with ONFH, the results showed 6 cases cured, 13 cases markedly improved, 16 cases improved, and 7 cases of failures [14].
Table 1. Classification systems of osteonecrosis of the femoral head
Fig. 1. A photograph showing shockwave treatment of ONFH by Professor Wang.
The long-term follow-up of ESWT for ONFH was reported by Dr. Vulpiani et al. [11] in 2012 . The ESWT for treatment of 36 patients with ONFH was followed up at 3, 6, 12, and 24 months. The results were significantly associated with ARCO staging of the lesions after ESWT. Patients with early stage ONFH with ARCO stage I (100%) and stage II (81.8%) achieved excellent or good results than those in their late phase with ONFH with ARCO stage IIIa (26.7%) at follow-up (p < 0.005). Kusz demonstrated that ESWT resulted in considerable enhancement of quality of life in ONFH patients. Patients experienced pain reduction (visual analogue pain score decreased from 6.75 to 2.5) and increased mobility of the treated hip joint. Harris hip score increased from 55.21 to 89.21. However, they only followed up patients for 6 weeks [15]. In the same year, Wang et al. [16] reported long-term results of ESWT and core decompression in ONFH with 8- to 9-year follow-up. There were 48 patients with 57 hips in the study. The ESWT group consisted of 23 patients with 29 hips and the core decompression group had 25 patients with 28 hips. The functional results showed that 76% of hips were good or fair and 24% were poor after ESWT. On the other hand, 21% of hips were rated good or fair and 79% poor after core decompression. The results demonstrated that ESWT had better results than surgery in the treatment of early ONFH in long-term follow-up. Similar results were reported by Lee et al. [17]. They evaluated 24 patients with ARCO-staged ONFH in 32 hip joints that were treated with ESWT and follow-up from 1993 to 2012. The visual analogue scale scoring in group 1 (ARCO stages I and II) showed a median of 7–1.5 (p < 0.001) and group 2 (ARCO stage III) showed a mean of 7 to 4 (p = 0.056). In Harris hip score (HHS) analysis, group 1 showed significant improvement from 65.5 to 95 (p < 0.001), but the improvement was non-significant for group II (p = 0.280). The results indicated that ESWT was effective in early and mid-stage of ONFH. The largest patient population on this topic was reported by Gao et al. [18]. They showed a total of 335 patients with 528 hips treated with ESWT and followed up at 3, 6, and 12 months. The pain reduction (p = 0.00006) improved mobility of the treated hips (p = 0.00091), and bone marrow edema (p = 0.007) showed significant improvement after ESWT. The lesion size decreased after ESWT, but the differences were nonsignificant. Wang et al. [19] demonstrated that high dosage ESWT was more effective in the treatment of early-stage ONFH. They recruited 32 patients (42 hips) randomly and divided them into three groups. Group A (10 patients with 16 hips) received 2,000 impulses of ESWT at 0.510 mJ/mm2 to each hip. Group B (11 patients with 14 hips) and group C (12 patients with 12 hips) received 4,000 and 6,000 impulses of ESWT to each hip respectively. The high-dosage group C showed significant improvement in pain score (p = 0.037) and Harris hip score (p = 0.017) than group A and B at 6 month follow-up. One case report showed radial ESWT improved joint effusion, bone density for treatment of ARCO stage IV ONFH [20]. Additional studies are needed to clarify the use of radial ESWT with particular reference to ONFH.
The Synergistic Effect and Cocktail Therapy of ESWT in ONFH Treatments
In 2003, 4 healthcare workers including 3 women and 1 man with an average age of 26 years were affected by severe acute respiratory syndrome and were treated with a massive dose of corticosteroids that resulted in the development of early ONFH [21]. Those patients were treated with cocktail therapy that consisted of ESWT, HBO therapy, and alendronate. The practical applications of treatments were processed on 4 patients with 8 hips. First, each hip was treated with 6,000 impulses of shockwave at 0.62 mJ/mm2 energy flux density (EFD) in a single session. Then, HBO was performed once a day, 5 times a week for a total of 100 sessions. Patients received alendronate sodium 70 mg per week for 1 year. All patients returned to work as health care providers, and none of the hips required surgery during the 4 years follow-up period.
Fig. 2. The right hip before and after treatment showed the reduction of bone marrow edema and no further collapse; lesions of the femoral heads on MRI.
Our study also compared the effect of ESWT with and without alendronate for treatment of ONFH [22].
