High Energy Focused Extracorporeal Shock Wave therapy for early and mid stage femoral head necrosis: A single center Retrospective Cohort Study

Background: Research has shown that extracorporeal shock wave therapy has a certain therapeutic effect on the osteonecrosis of the femoral head (ONFH). However, the sample sizes are relatively small. The aim of this study is to evaluate and investigate the clinical efficacy and safety of high-energy extracorporeal shock wave treatment (ESWT) in the management of early and mid-stage ONFH by observing a large size clinical sample. Materials & Methods: 453 patients with stage I–III ONFH treated ESWT in our hospital between June 2019 to August 2021, are included. The visual analog pain scale (VAS), Harris hip score, radiography, and magnetic resonance imaging were used to estimate treatment results. The progression of ONFH was evaluated by imaging examination and clinical outcomes. Results: The mean follow-up was 39.81±7.94 months (range 26 to 50 months). The mean VAS decreased from 5.54 ± 1.19 before ESWT treatment to 1.92 ± 0.43 points at the 12 months follow-up (p < 0.001). The mean Harris hip score improved from 75.51 ± 5.14 before ESWT treatment, to 92.21 ± 4.53 at the 12 months follow-up (p < 0.001). The clinical success(improvement) was observed in 85.71% of ARCO stage I patients, 48.09% of ARCO stage II patients, and 49.15% of ARCO stage III patients. Imaging success (no worsening of clinical images) was observed in 12.38% stage I hips, 28.37% of stage II hips, and 27.12% of stage III hips, respectively. The hip joint survival rate of stage Ⅱ and stage Ⅲ patients was 86.51% and 77.97% (P<0.05). Conclusions: The result of the current study suggests that ESWT definitely represents an effective, reliable, and safe therapeutic method for early and middle stages of ONFH with bone marrow edema syndrome (BMES), and should be recommended as a therapeutic option. Keywords: High-energy extracorporeal shock wave therapy, Osteonecrosis, Femoral head, Bone marrow edema.