This is a retrospective observational study. The dataset was derived from 75 patients with femoral head necrosis; all participants were enrolled to participate in a non-inferiority study in outpatient rehabilitation medicine department of The Third Medical Center of Chinese People’s Liberation Army General Hospital. This retrospective study conformed with the ethical guidelines of the Declaration of Helsinki. It was approved by the Ethics Committee of The Third Medical Center of Chinese People’s Liberation Army General Hospital (ID: 001-R1) and registered on the Chinese Clinical Trial Registry.
This work has been reported in line with the STROCSS (Strengthening the Reporting of Cohort Studies in Surgery) criteria15.
The patient data was from our hospital between June 2021 and July 2023. All subjects affected by ONFH associated with hip pain and dysfunction received ESWT treatment. All patients signed an informed consent form at admission and were notified that their information might be used in a clinical study. Eligibility criteria were as follows: (1) Adult age (18–75 years); (2) Diagnosed as ONFH and Association Research Circulation Osseous staging I-IV, confirmed with a plain radiograph and MRI; (3)Participants met the inclusion criteria, and informed consent has been signed; (4) Participants received ESWT, and complete follow-up data were obtained. General contraindications to shock wave therapy were considered, including the use of a pacemaker, pregnancy, bleeding disorder, anticoagulant drug use, cancer in the focal area, or periodical follow-up data that were incomplete. Patients with any of these contraindications were excluded. Clinical information such as etiology, age, sex, body mass index (BMI), duration of symptoms, physical examination, past treatment experiences and medication history, diabetes mellitus, cigarette use, alcohol consumption, and hypercholesterolemia. Imaging data include: MRI image and X-ray image.
All patients had imaging (X-ray/MRI) performed on admission and received ESWT treatment. ESWT was performed using the following procedure: The junctional zone between normal and necrotic bone within the femoral head was delineated under the guidance of the C-arm. Within the junctional zone, 2 or 3 points approximately 1.0 cm apart were chosen under C-arm guidance and measured the distance between the necrotic area and the skin(with avoidance of keeping essential blood vessels and nerves). Then, the corresponding locations were marked on the skin in the groin area. The water sac was adjusted to the appropriate position, and the proper amount of medical coupling agent was applied to the surface of the water in contact with the human body. The application of focused ESWT equipment (HK.SWT-007; Huikan AG, China) was conducted without anesthesia by the same experienced orthopedist. Finally, when using 5–10 grade energy therapy (energy flow density: 0.18-0.60mJ/mm2), the energy was increased from low to high according to the subject’s sensitivity to pain. Simultaneously, to ensure exact targeting, the position was monitored throughout treatment, and the drift of the treatment point was adjusted in real-time. All patients had undergone ESWT with several cycles. The time the pain recurred was considered as the timing of the intervention once again. If this situation did not occur, participants would be treated 4 more cycles over 1 year, at 3-month intervals. Each treatment cycle included 5 sessions with 1000 impulses per point, each administered at a frequency of 60 times per minute, at 48–72 h intervals. Harris, VAS, MRI, and X-ray images were collected at 3 month and 1 year after treatment.
MRI-3D reconstruction method: First, raw MRI data from imaging of both hip joints (Digital Imaging and Communication in Medicine coronal T1-weighted MRI) were imported to the interactive medical imaging control system software (Mimics; Materialise Company, Laueven, Belgium). A three-dimensional (3D) view of the femoral head and its size of the necrotic volume was obtained by image segmentation, visualization, registration, and other functions(The necrotic area is confirmed by 2–3 specialists).
All the analyses were performed using SPSS 23.0 (IBM Corp, Armonk, NY) and Graphpad5.0 software (La Jolla, CA, United States). All statistical tests were bilateral, and P < 0.05 was considered statistically significant. Data of continuous variables were presented as mean ± SD if normally distributed and median (interquartile range, IQR) otherwise. A paired sample t-test was used to compare the mean change of each evaluation indicator between the pre-treatment and scheduled follow-up time points. Personal correlation analysis was performed to examine the correlation between the size of the necrotic volume and Harris, VAS, before treatment. A regression analysis was performed to verify the correlation between necrotic volume and Harris, VAS before treatment, and the correlation between the reduction of necrotic volume size and the improvement of HHS score 1 year after treatment.