Abstract
Objective
At present, due to the lack of early observation methods, the effect of the ‘accordion’ technique on the treatment of nonunion of the docking site varies greatly. In this study, color Doppler ultrasound was used to observe the docking site's local changes and investigate the relationship between local microenvironment changes and bone healing after the accordion technique.
Methods
30 patients with tibial bone transport treated at the Department of Orthopedics, Second Hospital of Shanxi Medical University, from May 2018 to June 2022, were analyzed retrospectively. Paired‐sample t‐tests were used for data that conformed to a normal distribution, and paired rank‐sum tests were used for before‐and‐after comparisons that did not conform to a normal distribution. There were 26 males and 4 females, aged 47.3 ± 11.7 years. Before bone transport, the defect gap between tibial bone ends was 6.80 ± 3.61 cm. The steps of the accordion technique were as follows: compression for 7 days, ultrasonic study of the microenvironment at the docking site, distraction for 12 days, latency for 7 days, compression for 14 days, then static fixation and radiological study until complete bone healing. Ultrasound was used to detect the size of the hematoma after 7 days of pressure, and the changes in blood flow before and after the ‘accordion' operation.
Results
All patients were followed up for 11.9 ± 1.9 months. At the last follow‐up, 22 patients achieved bone healing at the docking site after the treatment of the ‘accordion’ technique. There was a linear negative correlation between the size of the hematoma and the time of bone healing at the docking site (r = −0.639, p < 0.01). According to the Paley healing criteria, 18 of the 22 patients were excellent, and 4 patients were good.
Conclusion
Hematoma is necessary for the ‘accordion’ technique's success in the treatment of nonunion. The size of the hematoma is negatively related to the time of bone healing. The ‘accordion’ technique can increase the blood flow of tissue around the docking site. Ultrasound can be used to monitor the changes in the microenvironment at the docking site during the ‘accordion’ technique and guide the exact plan and prognosis of the ‘accordion’ technique.
Keywords: Accordion Technique, Blood Flow, Bone Healing, Docking Site, Hematoma
Hematoma formation is crucial for the successful treatment of non‐union at the docking site using the ‘accordion’ technique.
Introduction
While open fractures caused by high‐energy trauma are increasing, refractory diseases such as chronic osteomyelitis, infectious bone nonunion, and infectious bone defect caused by open fractures are increasing subsequently. Bone transport is currently the gold standard in the treatment of large segment bone defects of limbs, especially in cases complicated by infection, 1 and delayed union and nonunion at the docking site are important factors affecting the efficacy of this technique and the course of patients' disease. 2 , 3 The radiological study showed that the docking site was hardened, round, and blunt. During the operation, hardening of the docking site, closure of the pulp cavity, and even scar tissue embedded in the two broken ends were observed. 4 Repeated infections, surgeries, and local soft tissue defects cause local blood supply abnormalities. Therefore, the clinical manifestations of nonunion at the docking site are very similar to those of atrophic bone nonunion, and simply improving the mechanical stability of the broken end often cannot effectively restart bone union, resulting in prolonged treatment duration. At present, the commonly used treatment options for docking sites or nonunion of the docking sites are cortical exfoliation and autologous bone transplantation. 5 , 6 Still, this method has disadvantages, such as greater surgical trauma and tissue damage in the donor area. The accordion technique is a noninvasive treatment method derived from the noninvasive osteogenic technique of bone transport.
This group has found in their clinical work that by implementing the axial “compression distraction recompression” force on the long tubular bone, the union at the docking site restarts the bone healing process, induces docking site regeneration, and even accelerates bone healing. The ‘accordion’ technique promotes bone healing by using alternating compression‐distraction stimulation, which has the advantages of no further operation, no bone grafting, no donor area damage, a controllable treatment process, and noninvasive correction of alignment abnormalities at the docking site to a certain extent. 7 However, the group found that the success rate of the ‘accordion’ technique reported in the literature varies greatly. Giotakis et al. 6 reported the ‘accordion’ operation under X‐ray monitoring to treat 5 patients with nonunion of the docking site, 2 of which were successfully healed. Among the 8 patients treated by Hatzokos et al. 8 6 were successfully healed. However, all the 11 patients treated by Lu Yanjun 9 et al. achieved bone healing. It can be seen that although the accordion technique has obvious advantages, its literature reports are few, the number of cases is limited, and the effective rate is different (10%–50%). 10 , 11 Finding the pattern of the ‘accordion’ technique that is effective in the treatment is a problem that needs to be solved urgently.
Early signs of bone healing 12 , 13 and early new callus formation can be observed after fracture under ultrasonic monitoring. 14 , 15 Therefore, we collected and analyzed the ultrasonic monitoring results during the ‘accordion’ technique of the docking site after bone transport and other clinical data of 30 cases admitted to our hospital after tibial bone relocation, aiming to discover the early ultrasonic changes and their rules in the process of bone healing at the docking site relocation and explore the relationship between them and bone healing.
Materials and Methods
General Information
Inclusion criteria: (1) Patients diagnosed with chronic osteomyelitis; (2) Patients who underwent bone transport; (3) The docking site was treated with the accordion technique, and the ultrasound and X‐ray data were complete.
Exclusion criteria: (1) Poor compliance, inability to adjust the outer frame according to the doctor's order; (2) Ultrasound and X‐ray examinations were not performed regularly, or the follow‐up data were incomplete.
According to the inclusion and exclusion criteria, 30 patients were included in this study. There were 26 males and 4 females, aged 47.3 ± 11.7 years (range: 22–65 years). All 30 patients had chronic tibial osteomyelitis, of which 3 were blood‐derived tibial osteomyelitis, 14 were closed tibial fractures, and 13 were open tibial fractures. There were 4 patients with varus foot deformity, 3 with hypertension, 1 with type 2 diabetes, and 2 with tibia deformity. Before bone transport, the gap of the tibial defect was 6.80 ± 3.61 cm (range: 3.09–22.1 cm). All patients signed informed consent forms for treatment and examination. This study was approved by the Medical Ethics Committee of our hospital [batch No.: (2019) YX No. (182)].
Treatment Methods
The same team treated all patients. A preoperative assessment was performed. Blood glucose and blood pressure were adjusted to normal levels. Patients were placed in a supine position under general anesthesia or intraspinal anesthesia. The surgical area was disinfected, and a sterile sheet was applied. An annular external fixator of appropriate diameter (Shandong Juntai Ande Medical Technology Co., Ltd) was placed in the affected limb. By the technical requirements of the external tibial fixator, two sets of Kirschner wire (diameter 2.0 or 2.5 mm) were crossed into the proximal and distal tibial rings to fix the affected limb without damaging blood vessels and nerves. Note that the direction of the tibial bone was parallel to the long axis of the external tibial fixator. One or two screw needles (diameter 4.0 or 5.0 mm) were inserted into the proximal and distal tibia rings and connected to the external fixator. Three threaded pins (diameter 4.0 mm) are inserted into the middle moving assembly to fix the moving bone ends. A foot and ankle orthosis component was performed in patients with foot and ankle deformity. During tibial osteotomy, a 1.5‐ to 2.0‐cm skin incision was made, lateral drilling was performed with a minimally invasive osteotomy, and the tibia was truncated along the drilling plane with an osteotome. Adjust the moving assembly so that the osteotomy end is pressed and closed, the incision is stitched, the drainage strips are indwelled, and the dressings are pressed and bandaged. Thoroughly clean the infected tissue of the broken end, rinse with a large amount of normal saline (more than 10,000 mm), fill the bone defect area with an antibiotic bone cement bead, select sensitive antibiotics mixed with bone cement (Heraeus Medical GmbH, COPAL spacem) according to the drug sensitivity results, and sew the wound. Tweleve days after surgery, the patient was instructed to carry out bone transport, and the longitudinal movement of the bone segment was controlled by adjusting the moving component. The adjustment rate was 5/6 mm per day, completed five times. Strengthen functional exercise and walking gradually after the operation and change dressing regularly; regular needle care, prevention of needle infection; and the accordion technique is performed after moving to the docking site contact. The steps of the accordion technique were as follows: compression for 7 days, the ultrasonic study of the microenvironment at the docking site, a distraction for 12 days, latency for 7 days, compression for 14 days, then static fixation and regular radiological study until complete bone healing.
Ultrasound Examination
EPIQ7 ultrasonic equipment and linear array probe produced by Netherlands Royal Philips Electronics are selected, and the probe frequency is 3–9 MHz. All patients underwent ultrasound examination at the contact of the docking site, 7 days after compression, 12 days after distraction, and 14 days after retraction. During the examination, the patient was placed in a supine position, the affected limb was flexed, and the involuntary end was fully exposed. The probe was placed on the part of thin, soft tissue, and the anterior tibia skin (12 o'clock direction) and the medial tibia skin (9 o'clock direction) were respectively collected. The ultrasound images were collected parallel to the tibia axis longitudinally and perpendicular to the tibia axis horizontally. The hematomas and callus of the docking site were observed by two‐dimensional ultrasound. Color Doppler was used to observe the richness of the surrounding blood flow. Spectral Doppler measured V s (peak systolic flow rate) and V d (end‐diastolic flow rate), and then calculated vascular resistance index (RI), pulsation index (PI), and average blood flow velocity (MV). All procedures and image acquisition were performed by the same ultrasound physician with more than 15 years of experience and in case of doubt, they were jointly evaluated by another experienced ultrasound physician.
Observation Indicators
Observe whether there is hematoma (area/cm2) in the superficial layer of the bone cortex after 7 days of contact and compression at the docking site.
The changes in blood flow signals at the docking site before and after the ‘accordion’ technique included vascular RI, PI, MV, and blood flow richness, and were evaluated according to blood flow Alder 16 Grading. The specific grades are as follows: Grade 0: No blood flow signal; Grade I: Small local blood flow signal, 1–2 spots or rod‐shaped signals; Grade II: Moderate local blood flow, 3–4 spots or one clear signal; Grade III: Abundant local blood flow, over 5 spots or 2 clear signals.
The formation of new callus and the morphology of the callus were observed 12 days after the docking site was distracted.
After the ‘accordion’ technique, the bone healing of the docking site was evaluated according to the Paley 17 bone defect evaluation criteria at the last follow‐up, which could be divided into four grades: excellent, good, fair, and poor. Fracture healing, no recurrent infection, residual deformity <7°, limb asymmetry <2.5 cm were rated as excellent; Fracture healing, combined with any two of the other three, was rated as good; fracture healing, combined with any one of the other three was rated as acceptable; nonunion or repeated fractures were rated as poor (Tables 1, 2, 3).
TABLE 1.
General data of 30 patients with bone defects treated with tibial bone transport.
| Patient number | Sex | Age (years) | Cause of disease | Complication | Bone defect site | Osteotomy range (cm) | Complication |
|---|---|---|---|---|---|---|---|
| 1 | Female | 42 | Chronic osteomyelitis | Talipes equino‐varus | Right | 3.38 | Pin site infection |
| 2 | Male | 60 | Chronic osteomyelitis | Nil | Left | 3.09 | Nil |
| 3 | Male | 44 | Chronic osteomyelitis | Talipes equino‐varus | Left | 5.30 | Malalignment |
| 4 | Male | 41 | Chronic osteomyelitis | Nil | Left | 3.69 | Nil |
| 5 | Male | 55 | Chronic osteomyelitis | Type 2 diabetes mellitus | Left | 7.66 | Nil |
| 6 | Male | 37 | Chronic osteomyelitis | Nil | Right | 5.27 | Nil |
| 7 | Male | 61 | Chronic osteomyelitis | Talipes equino‐varus | left | 8.71 | Pin site infection |
| 8 | Male | 43 | Chronic osteomyelitis | Nil | Right | 5.43 | Nil |
| 9 | Male | 54 | Chronic osteomyelitis | Nil | Right | 5.79 | Malalignment |
| 10 | Male | 41 | Chronic osteomyelitis | Nil | Right | 10.02 | Pin site infection |
| 11 | Male | 33 | Chronic osteomyelitis | Nil | Right | 6.01 | Nil |
| 12 | Male | 61 | Chronic osteomyelitis | Nil | Left | 9.03 | Nil |
| 13 | Male | 34 | Chronic osteomyelitis | Nil | Left | 6.02 | Pin site infection |
| 14 | Female | 46 | Chronic osteomyelitis | Deformed healing of the tibia | Right | 3.28 | Malalignment |
| 15 | Male | 41 | Chronic osteomyelitis | Hypertension | Right | 7.58 | Nil |
| 16 | Male | 31 | Chronic osteomyelitis | Nil | Left | 9.12 | Genu varum |
| 17 | Male | 22 | Chronic osteomyelitis | Nil | Right | 5.82 | Knee joint stiffness |
| 18 | Male | 60 | Chronic osteomyelitis | Nil | Left | 9.51 | Nil |
| 19 | Male | 53 | Chronic osteomyelitis | Nil | Right | 8.01 | Nil |
| 20 | Male | 61 | Chronic osteomyelitis | Nil | Right | 3.21 | Nil |
| 21 | Female | 56 | Chronic osteomyelitis | Nil | Right | 4.70 | Genu valgum |
| 22 | Male | 49 | Chronic osteomyelitis | Talipes equino‐varus | Left | 4.12 | Pin site infection |
| 23 | Female | 65 | Chronic osteomyelitis | Hypertension | Left | 4.84 | Malalignment |
| 24 | Male | 58 | Chronic osteomyelitis | Nil | Left | 22.1 | Malalignment |
| 25 | Male | 36 | Chronic osteomyelitis | Hypertension | Right | 10.5 | Talipes Equino‐varus |
| 26 | Male | 59 | Chronic osteomyelitis | Deformed healing of the tibia | Left | 3.99 | Malalignment |
| 27 | Male | 31 | Chronic osteomyelitis | Nil | Right | 6.28 | Malalignment |
| 28 | Male | 34 | Chronic osteomyelitis | Nil | Left | 8.12 | Malalignment |
| 29 | Male | 56 | Chronic osteomyelitis | Nil | Right | 5.78 | Pin site infection |
| 30 | Male | 56 | Chronic osteomyelitis | Nil | Right | 7.44 | Nil |
TABLE 2.
Index changes of 22 patients before and after accordion treatment.
| Grouping | x ± s | Difference and 95% CI | t‐test | |
|---|---|---|---|---|
| T value | p value | |||
| (1) Blood flow MV | ||||
| Before treatment | 4.59 ± 2.65 | −0.37 (−0.95–0.2) | −1.341 | 0.194 |
| Posttreatment | 4.96 ± 2.95 | |||
| (2) Blood flow RI | ||||
| Before treatment | 0.57 ± 0.1 | 0.08 (0.05–0.12) | 4.69 | <0.001 |
| Posttreatment | 0.48 ± 0.1 | |||
| Grouping | Rank sum | Test | ||
|---|---|---|---|---|
| Median (P25, P75) | Difference and 95% CI | Z value | p value | |
| (3) PI of blood flow | ||||
| Before treatment | 0.89 (0.78,1.09) | 0.08 (0.05–0.12) | 3.69 | <0.001 |
| Posttreatment | 0.73 (0.54,0.82) | |||
| Number of cases | Average rank | The sum of ranks | ||||
|---|---|---|---|---|---|---|
| (4) Alder classification | ||||||
| Posttreatment‐ | Before treatment | Negative rank | 3a | 15.00 | 45.00 | |
| Positive rank | 53b | 29.26 | 1551.00 | |||
| Binding value | 24c | |||||
| Grand total | 80 | |||||
| a. Posttreatment | <Before treatment | b. Posttreatment | >Before treatment | c. Posttreatment = | Before treatment | |
| Test statistics | ||||||
| Posttreatment | Before treatment | |||||
| Z | −6.339b | |||||
| Asymptotic significance | (Double tail) | |||||
| 0.000 | ||||||
| a. Wilcoxon | Signed‐rank test | b. Based on | Negative rank | |||
Note: “a” refers to after treatment < before treatment, “b” to after treatment > before treatment, and “c” to after treatment = before treatment. The second table is the test statistics, where “a” refers to the Wilcoxon signed‐rank test, and “b” refers to tests based on negative ranks.
TABLE 3.
The relationship between the size of hematoma and bone healing time in 22 patients.
| Hematoma | Healing time | ||||
|---|---|---|---|---|---|
| Hematoma | Pearson | Correlation | 1 | −0.639 | |
| Sig (double tail) | 0.001 | ||||
| Number of cases | 22 | 22 | |||
| Healing | Time | Pearson | Correlation | −0.639 | 1 |
| Sig (double tail) | 0.001 | ||||
| Number of cases | 22 | 22 | |||
| At 0.01 level | (Double tail) | Significant correlation | 8 |
| Coefficient a | |||||
|---|---|---|---|---|---|
| Unstandardized | Coefficient | Standardization | Coefficient | ||
| B | STDERR | Beta | t | ||
| Constant | 36.543 | 1.677 | 21.792 | 0.000 | |
| Hematoma | −12.482 | 3.358 | −0.639 | −3.718 | 0.001 |
| a.Dependent variable | Healing time |
Statistical Processing
SPSS 25.0 statistical software (IBM Corporation, USA) was used to analyze the data. Normal distribution data were expressed as x ± s, and the paired sample t‐test was used to compare before and after the operation. Data that did not conform to the normal distribution were expressed as “Mean (P25, P75),” and the paired rank sum test was used for the front‐to‐back ratio; p < 0.05 was considered statistically significant. The size of the hematoma and the time of bone healing were analyzed by correlation analysis and single‐factor linear regression. Bone healing time and blood flow RI, blood flow PI, blood flow MV, and blood flow Alder Grades were correlated, and p < 0.05 was considered a statistically significant difference.
Results
Formation of Hematoma at the Docking Site
Thirty patients were studied. During the ‘accordion’ technique at the docking site, hematoma appeared around the bone cortex in 26 patients after 7 days of compression at the docking site, and the ‘accordion’ technique was further completed. In four patients with ‘accordion’ treatment, the broken end alignment and alignment were poor, and then the fractured end resection and autogenous bone transplantation were performed. After continuous pressure, ultrasound monitoring of four patients did not find the formation of a hematoma. The formation of a new callus was not found at the broken end, so cortical exfoliation and autogenous bone transplantation were performed. Therefore, these eight patients were not included in the data analysis, and the remaining 22 patients with hematomas after compression of the conjoint end were measured, the size of which ranged from 0.103 to 0.887 cm2, with an average value of 0.732 ± 0.181 cm2. Thereafter, the hematoma gradually became mechanized (ultrasound showed increased echo).
Changes in the Blood Flow Signal
The blood flow RI of 22 patients before the ‘accordion’ technique was 0.57 ± 0.1, the blood flow RI after the operation was 0.48 ± 0.1, and the blood flow RI after treatment decreased. The paired t‐test showed a statistical difference in the overall mean of data before and after the operation (d = 0.08, 95% CI: 0.05–0.12, 95% CI: 0.05–0.12, p < 0.001). Before treatment, the blood flow PI was 0.89 (0.78, 1.09); after treatment, the blood flow PI was 0.73 (0.54, 0.82). The paired rank sum test showed a statistically significant difference in the overall distribution of the two groups (Z = 3.69, p < 0.001). Before treatment, the blood flow MV was 4.59 ± 2.65 (cm/s), and after treatment, the blood flow MV was 4.96 ± 2.9 (cm/s), and the paired t‐test showed no statistically significant difference between the two groups (p > 0.05).
The blood flow richness of the docking site was evaluated by ultrasound. According to the Adler grading evaluation, among the 22 patients, 1 case was grade 0 before the ‘accordion’ technique, 12 cases were grade I, 2 cases were grade II, and 7 cases were grade III. After treatment, the blood flow Alder Grading of all patients was found to be increased. The difference was statistically significant by paired rank sum test (Z = –6.339, p < 0.001).
New Callus Formation
Ultrasonography was performed in 22 patients 12 days after retracting, and it was found that hematoma was institutionalized and a callus was formed in the retracting space (high echo area under ultrasonic observation). In 15 patients, the morphology of the new callus was spot‐like. Four cases showed a dot line shape, and three cases were lamellar.
Bone Healing
After the ‘accordion’ technique, all patients were moved to the fixed components, rehabilitation exercises were performed, and new bone mineralization in the extension area was observed. X‐ray examination was performed regularly to check the healing of the docking site. At the last follow‐up of the 22 patients, an X‐ray showed that the docking site had reached bone healing. According to Paley's healing criteria, 18 cases were excellent and 4 cases were good. Furthermore, it was found that the size of the hematoma in the early stage affected the condition of bone healing in the later stage. The correlation coefficient was used to analyze the effect, and the correlation between the size of the hematoma and the time of bone healing was statistically different (r = −0.639, p = 0.001). Simple linear regression showed that bone healing time decreased by 12.482 weeks for every 1 cm2 increase in hematoma size. There was no statistical significance in the correlation coefficient analysis between blood flow RI, blood flow PI, blood flow MV, blood flow Adler, and bone healing time (Figures 1 and 2).
FIGURE 1.
A 23‐year‐old man with chronic osteomyelitis of the right tibia is treated with bone transport. When the docking site contacts, the ‘accordion’ technique is performed regularly. (A) Longitudinal scan and (B) transverse scan of the docking site shows local hematoma formation. (C) X‐ray examination shows contact with the docking site. (D) The patient's ‘accordion’ technique 80 days later, the review shows the healing of the docking site. (E) After 150 days of the patient's ‘accordion’ technique, the review shows that the fracture line at the docking site disappeared, and the bone remodeling was completed. D/E The patient's bone has healed, and the fixation device of some threaded needles has been removed to improve the stress of bone tissue and promote bone reconstruction. In accordion treatment, the broken end is pressurized, and the thread needle is bent by force.
FIGURE 2.
A 57‐year‐old woman with chronic osteomyelitis of the right tibia is treated with bone transport. When the docking site contacts, the ‘accordion’ technique is performed regularly. (A) Longitudinal scan and (B) transverse scan of the docking site shows local hematoma formation. (C) X‐ray examination shows contact with the docking site. (D) The patient's ‘accordion’ technique was used 53 days later, and the review shows the bone scab formation at the docking site. (E) After 190 days of the patient's ‘accordion’ technique, the review shows that the fracture line at the docking site disappeared, and the bone remodeling was completed.
Treatment of Complications
All 30 patients were followed up, and all 30 patients had needle reactions. After timely dressing changes and needle care, they were improved, and no needle infection occurred. In eight patients, there was poor alignment and alignment of the conjoint end in the process of moving, and four of them were adjusted in the outpatient department, corrected in time, and completed the ‘accordion’ technique. Four cases were not corrected and underwent surgical treatment. The deformity of the knee varus and valgus appeared in two cases, respectively, which was gradually corrected by adjusting the shape of the external ring fixator. One patient had knee flexion deformity, poor recovery after rehabilitation forging, and improved after treatment. One case of foot deformity of equine varus was corrected by foot and ankle orthosis.
Discussion
Changes in the Microenvironment of the Butt‐End Under Ultrasound Detection
The present study was conducted to observe the changes in the docking site during treatment with the ‘accordion’ technique by applying color Doppler ultrasound. Specific indicators include hematoma formation at the docking site, changes in blood flow signals, new bone scab formation, bone healing, etc. The analysis of the observed local hematomas, RI, PI, MV, etc., and data of the 30 enrolled patients revealed a relationship between the formation of local hematomas and the increase in blood flow and the time to bone healing. Thus, this group believes that color Doppler ultrasound can be used as an early monitoring tool to predict the prognosis of bone healing at the docking site, allowing some patients to avoid secondary surgery and accelerate bone healing.
Thus, this study used high‐frequency color Doppler ultrasound as an early monitoring method. During the treatment, the changes in the microenvironment at the end of the anastomosis were researched. It was found that after full compression at the docking site, the cases of large hematoma formation were observed by ultrasound, the callus formation was more evident during the ‘accordion’ technique, and bone healing was faster after treatment. In cases with smaller hematomas at the involution end, less callus formation was observed during treatment, and slower bone healing was achieved after treatment. We conducted a statistical analysis of the size of the hematoma and the bone healing time after treatment with the ‘accordion’ technique. We found a statistical difference in the correlation between the two patients (r = −0.639, p = 0.001). The larger the hematoma, the faster the bone healing. This indicates that hematoma can effectively promote callus formation at the docking site and is negatively correlated with the bone healing time. Therefore, we believe whether a hematoma is formed by sufficient compression and the size of the hematoma will directly affect the success rate of the ‘accordion’ technique for the treatment of docking site bone nonunion.
In fracture healing, local blood supply plays a vital role in maintaining callus growth and bone reconstruction, and local bone repair is closely related to blood flow. 18 August et al. 19 used ultrasound to monitor continuously the blood flow at the docking site of the fracture. They found that those with good callus formation had abundant blood flow signals around them, while those with poor callus formation often lacked blood flow signals around them. In this study, it was found that the elevation of ultrasound Adler grade before and after the treatment with the operation at the docking site resulted in an increase in local blood flow, which was statistically significant, indicating that the local blood supply of patients after the treatment was significantly increased. Blood flow RI is the blood supply RI, and blood flow PI is the number of blood vessel pulsations. Both RI and PI decreased after treatment with statistical significance, indicating a decrease in local blood flow resistance and an increase in blood flow at the docking site. By analyzing the patients who healed after the operation of the ‘accordion’ technique, it was found that the growth of the callus could be found in the traction stage and the recompression stage. Combined with the above results, it can be found that the blood supply at the broken end of the fracture was significantly improved after the treatment with the ‘accordion’ technique, and the increased blood supply was conducive to callus growth and could form a microenvironment that effectively promoted bone healing.
However, this study found that blood flow MV increased before and after the ‘accordion’ technique by ultrasound, but there was no statistical significance. At the same time, it was also found that the changes in docking site blood flow RI, blood PI, blood MV, blood flow Adler grade, and bone healing time were not statistically significant when analyzed separately. However, it was found during ultrasound observation that the lower the docking site blood flow RI and PI after the accordion technique, the higher the blood flow Adler grade. The more abundant the early callus of the local particular end, we believe there may be a positive correlation between the increase in local blood supply and the amount of new callus in the early stage. However, we have not quantitatively analyzed and observed the amount of callus, so no effective results have been obtained.
Mechanism of the Accordion Technique to Promote Bone Healing at the Docking Site and the Need for Ultrasound Observation, as Hypothesized in this Study
At present, the mechanism of the ‘accordion’ technique to promote the docking site's healing is not clear. In this study, among the patients who underwent the ‘accordion’ technique, local hematoma formation was found by ultrasound in 22 cases after 7 days of compression at the docking site. Then, new callus formation was seen around the docking site after 12 days of retraction and 14 days of recompression, and bone healing was finally achieved in all patients. Therefore, we speculate the possible mechanisms of the ‘accordion’ technique in the treatment of nonunion of the docking site: the change of compressive stress on the microenvironment of the joint end 20 (local microfractures and local changes caused by fractures, such as hematoma), and the reactivation of the bone healing system. Then, the microcirculation regeneration of the involutive end is promoted by the tensile stress, 21 which amplifies the compression effect and accelerates bone formation. Recompression increases local bone density and accelerates bone healing. We believe that the possible reasons for the different technical effectiveness of ‘accordion’ are as follows: X‐ray examinations are inadequate for detecting early callus formation and do not provide timely and effective feedback on the efficacy of the ‘accordion’ technique. This limitation can result in missed optimal treatment opportunities during the initial contact the conjunctival ends. Consequently, clinicians both domestically and internationally often rely on personal experience to formulate treatment plans, leading to a lack of standardized procedures. This variability affects the success rate of the technique and hinders its broader adoption and development. Currently, ultrasound technology, as a novel observation method, offers the ability to detect early‐stage microenxironmental changes at the zygomatic end, allowing for more accurate treatment prognosis.
Strengths and Weaknesses of this Study
The advantages of this study are as follows: the relationship between the changes in blood flow and hematoma at the docking site and the bone healing time of patients was found by high‐frequency Doppler ultrasound, which was more effective in predicting the prognosis of the ‘accordion’ technique treatment. This study still has the following shortcomings: (1) The number of cases is small, and there is no controlled study. (2) Quantitative ultrasound, energy spectrum CT, and bone densitometry are not used to quantitatively analyze new callus and other indicators. In further studies, the new callus and other indicators were quantitatively analyzed to obtain more accurate data, further realize the fine technique of the ‘accordion’ technique, and sum up an effective ‘accordion’ technique comprehensive treatment system.
Conclusion
In sum, hematoma is a necessary condition for successfully treating nonunion of the docking site by the ‘accordion’ technique. Ultrasonic monitoring of hematoma at the docking site can not only guide clinical treatment of the ‘accordion’ technique but also predict the final bone healing time according to the size of the hematoma.
Author Contributions
Conception and design experiments and perform surgery and drafting of the article: Dong Wang and Yong‐Hong Zhang. Acquisition of data: Shao‐Huang Liu and Guo‐Yu He. Ultrasound observations: Ze Zhang and Juan Li. Analysis of the data: Ru‐Qi Zhang and Jun‐Jun Shi. Assisting with surgeries and data collection: Ying‐Wei Jia, Hu‐Yun Qiao, Hong Liu, and Bao‐Na Wang. Critical review of the intellectual content of the article: Yong‐Hong Zhang and Si‐He Qin.
Funding Information
The project was supported by the National Natural Science Foundation of China (Grant No. 82172439): Study on the Mechanism of Periodic Mechanical Stimulation of Accordion Technology to Activate HIF‐1 Pathway and Restart Bone Healing.
Conflict of Interest Statement
All contributing authors report no conflict of interest in this work.
Ethics Statement
All patients signed informed consent forms for treatment and examination. This study strictly followed the Helsinki Declaration and was approved by the Medical Ethics Committee of our hospital [batch No. (2019) YX No. (182)].
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