Ankylosing spondylitis (AS) combined with lower cervical fracture is often categorized into unstable fracture, with a high incidence of neurological injury and a high rate of disability and morbidity. As factors such as shoulder occlusion may affect the accuracy of X-ray imaging diagnosis, it is often easily misdiagnosed at the primary diagnosis. Non-operative treatment has complications such as bone nonunion and the possibility of secondary neurological damage, while the timing, access and choice of surgical treatment are still controversial. Currently, there are no clinical practice guidelines for the treatment of AS combined with lower cervical fracture with or without dislocation. To this end, the Spinal Trauma Group of Orthopedics Branch of Chinese Medical Doctor Association organized experts to formulate Clinical guidelines for the treatment of ankylosing spondylitis combined with lower cervical fracture in adults ( version 2024) in accordance with the principles of evidence-based medicine, scientificity and practicality, in which 11 recommendations were put forward in terms of the diagnosis, imaging evaluation, typing and treatment, etc, to provide guidance for the diagnosis and treatment of AS combined with lower cervical fracture.

Objective:To investigate the risk factors of pleural effusion after spinal separation surgery for patients with spinal metastatic tumors.Methods:A total of 427 patients with spinal metastatic tumors from January 2014 to January 2022 in the Second Affiliated Hospital of Zhejiang University School of Medicine were retrospectively analyzed. There were 252 males and 175 females, with an average age of 59±12 years (range, 15-87 years). All patients underwent separation surgery. Based on the chest CT within 1 month after surgery, the volume of pleural effusion was measured individually by reconstruction software. Pleural effusion was defined as small volume (0-500 ml), moderate volume (500-1 000 ml), and large volume (above 1 000 ml). Baseline data and perioperative clinical outcomes were compared between the groups, and indicators with statistically significant differences were included in a binary logistic regression analysis to determine the independent risk factors for the development of pleural effusion after isolation of spinal metastatic cancer. Receiver operating characteristic (ROC) curves were conducted to calculate the area under the curve (AUC) for each independent risk factor.Results:All patients successfully completed the operation. Among the 427 patients, there were 35 cases of large pleural effusion, 42 cases of moderate pleural effusion, and 350 cases of small pleural effusion. There were significant differences in tumor size (χ 2=9.485, P=0.013), intraoperative blood loss ( Z=-2.503, P=0.011), blood transfusion ( Z=-2.983, P=0.003), preoperative total protein ( Z=2.681, P=0.007), preoperative albumin ( Z=1.720, P= 0.085), postoperative hemoglobin ( t=2.950, P=0.008), postoperative total protein ( Z=4.192, P<0.001), and postoperative albumin ( t=2.268, P=0.032) in the large pleural effusion group versus the small and moderate pleural effusion group. Logistic regression analysis showed that decreased preoperative albumin ( OR=0.89, P=0.045) and metastases located in the thoracic spine ( OR=4.01, P=0.039) were independent risk factors for the occurrence of large pleural effusion after separation surgery. The ROC curve showed that the AUC and 95% CI for preoperative albumin, lesion location, and the combined model were 0.637 (0.54, 0.74), 0.421 (0.36, 0.48), and 0.883 (0.81, 0.92). The combined predictive model showed good predictive value. Conclusion:The volume of pleural effusion can be measured individually and quantitatively based on chest CT. Decreased preoperative albumin and metastases located in the thoracic spine are independent risk factors for the occurrence of large pleural effusion after separation surgery. The combined prediction of the two factors has better predictive efficacy.

Objective:To investigate the risk factors for 1-year survival rate in patients with spinal metastasis secondary to lung cancer.Methods:The data of 343 patients with spinal metastases secondary to lung cancer from January 2011 to December 2018 were retrospectively studied. There were 188 males (54.8%) and 155 females (45.2%) with an average age of 59.47±10.21 years old (range 23-91 years). The patients were divided into operation group (150 cases, 43.7%) and non operation group (193 cases, 56.3%). The demographics, types of primary tumor, non spinal metastasis, visceral metastasis, spinal metastasis and segments, pathological fractures of vertebra, Frankel classification, physical function status (Karnofsky performance scale, KPS), visual analogue score (VAS), the spinal instability neoplastic score (SINS) were recorded and analyzed. The impact of different treatments on the survival prognosis of patients with spinal metastasis was evaluated. The independent factors affecting survival in those patients were analyzed by Cox proportional hazards regression model.Results:The peak incidence of spinal metastases was found in the age group of 46-60 years (43.7%, 150/343). 38.5% (132/343) of the patients had pathological fractures of the involved vertebral body. 58.3% (200/343) of the patients had extraspinal bone metastasis. 36.2% (124/343) of the patients had visceral metastasis. Among the primary tumors, adenocarcinoma was the most common tpye (61.5%, 211/343), followed by large cell lung cancer (12.5%, 43/343), small cell lung cancer (6.4%, 22/343), squamous cell cancer (6.1%, 21/343) and mixed cell lung cancer (5.3%, 18/343). The type of lung cancer cells in about 8.2 (28/343) patients was unknown. Among the surgical patients, 21 patients underwent minimally invasive surgery (14.0%), 28 patients underwent simple decompression surgery (18.7%), 76 patients underwent separation surgery (50.7%), and 25 patients underwent radical surgery (16.6%). 59.3% (89/150) of the patients had a better neurological function than before surgery. The average survival time of all patients was 9.88 months with the median survival time of 8 (5,14) months. The survival rates were 62.1% (213/343), 30.0% (103/343), and 3.8% (13/343) at 6, 12, and 24 months, respectively. The average survival time of patients in the operation group was 10.24 months with the median survival time of 9 (5, 15) months, and the average survival time of patients in the non operation group was 9.41 months with the median survival time of 7 (5, 13) months with no significant difference between the groups (χ 2=0.300, P=0.584). Multivariate Cox proportional hazard regression model analysis showed that radiotherapy [ HR=1.913, 95% CI(1.471, 2.488), P<0.001], chemotherapy [ HR=1.313, 95% CI(1.040, 1.658), P=0.022], targeted drug therapy [ HR=1.683, 95% CI(1.221, 2.319), P=0.001], KPS [ HR=1.593, 95% CI(1.140, 2.225), P=0.006] and pathological type (non-small cell lung cancer) were independent factors affecting the 1-year survival rate of patients with spinal metastasis secondary to lung cancer [ HR=0.322, 95% CI(0.225, 0.460), P<0.001] with significant difference. Conclusion:Surgical treatment can improve both the neurological function and general status of patients with spinal metastasis. Treatments of radiotherapy, chemotherapy, and targeted drug therapy can significantly improve 1-year survival rate, while a KPS less than 50 points and a primary lung cancer other than adenocarcinoma were independent risk factors reducing 1-year survival rate.

Objective:To compare the efficacy of modified single-incision and traditional double-incision for flexor hallucis longus tendon transfer in the treatment of Myerson type III chronic Achilles tendon ruptures in the middle-aged and elderly patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 106 patients with Myerson type III chronic Achilles tendon ruptures admitted to Ningbo No.6 Hospital from January 2015 to May 2021, including 54 males and 52 females; aged 48-82 years [(67.2±8.4)years]. Flexor hallucis longus tendon transfer was assigned to 60 patients using modified single-incision (modified single-incision group) and to 46 patients using traditional double-incision (traditional double-incision group). The operation time, intraoperative blood loss as well as American foot and ankle society (AOFAS) ankle-hindfoot score, foot and ankle outcome score (FAOS), visual analogue score (VAS) before operation, at postoperative 12 months and at the last follow-up were compared between the two groups. Time to recover walking and self-care ability, and incidence of complications were compared as well.Results:All patients were followed up for 16-52 months [(37.4±9.5)months]. The operation time and intraoperative blood loss were (51.6±7.4)minutes and (16.6±3.9)ml in modified single-incision group compared to (72.8±7.5)minutes and (32.9±5.2)ml in traditional double-incision group (all P<0.01). There was no significant difference in the AOFAS ankle-hindfoot score, FAOS and VAS between the two groups before operation (all P>0.05). At postoperative 12 months and at the last follow-up, AOFAS ankle-hindfoot score and VAS were not significantly different between the two groups (all P>0.05), but FAOS in modified single-incision group [(112.6±3.0)points, (114.4±3.1)points] was improved significantly compared with traditional double-incision group [(110.8±4.1)points, (112.7±4.3)points] ( P<0.05 or 0.01). At postoperative 12 months and at the last follow-up, the AOFAS ankle-hindfoot score, FAOS and VAS in both groups were improved or decreased significantly compared with those before operation (all P<0.05). All patients recovered their pre-injury daily activities. The time to recover walking and self-care ability were (9.6±2.0)weeks and (12.7±1.7)weeks in modified single-incision group compared to (10.8±1.8)weeks and (13.7±1.9)weeks in traditional double-incision group (all P<0.01). In modified single-incision group, superficial incision infection ( n=1) was found and cured after oral antibiotics. In traditional double-incision group, superficial incision infection ( n=2), deep incision infection ( n=1), deep venous thrombosis ( n=1) and medial plantar nerve injury ( n=1) were found and cured after symptomatic internal medical therapy; claw toe deformity ( n=2) was found and relieved after wearing customized insoles and functional exercise. The incidence of complications was 1.7% (1/60) in modified single-incision group compared to 15.2% (7/46) in traditional double-incision group ( P<0.01). Conclusion:In contrast with traditional double-incision surgery, modified single-incision for flexor longus tendon transfer in the treatment of Myerson type III chronic Achilles tendon ruptures in the middle-aged and elderly patients has advantages such as shorter operation time, less intraoperative blood loss, better functional recovery, faster postoperative recovery and less complications.

Objective:To investigate the surgical method and clinical effect of O-arm navigation mini-open burring for osteoid osteoma.Methods:Eighteen patients with osteoid osteoma were treated with O-arm guided grinding drill from June 2021 to May 2022, including 15 males and 3 females, the age was (18.4 ±10.9) years (range 2 to 44 years), and the course of disease ranged from 1 week to 3 years (mean 14.2 months). The lesions sites included 6 cases of proximal femur, 3 cases of distal femur, 4 cases of proximal tibia, 1 case of distal tibia, 2 cases of proximal fibula and 1 case of distal and proximal humerus. During the operation, the O-arm navigation was used to determine the location of the focus, the muscle and soft tissue was peeled off to the bone surface through a 1-4 cm small incision, the channel retractor was placed, and the burr was registered as a navigation recognition device to gradually remove the bone on the surface of the tumor nest, and the tumor nest was scraped with a curette for pathological examination; according to the navigation image, the focus was enlarged removed with burr and the grinding range was confirmed by the O-arm X-ray machine before the end of the operation. The patients were followed up for 6 to 15 months (mean 9.5 months). CT scans were performed before and after surgery for imaging comparison in order to figure out whether it had residual lesions or recurrence. The visual analogue score (VAS) of pain was used as a parameter for evaluating the clinical efficacy.Results:The operation time of 18 cases was 40-175 min, with an average of 89.3 min. The time required to establish navigation image was 18.0 ±4.1 min (range 13 ~ 22 min). The length of the incision was 2.7±1.1 cm (range 1-4 cm). All patients achieved complete curettage of the lesions, and osteoid osteoma was confirmed by pathology after operation. All the patients could move to the ground 24 hours after operation, and the pain was significantly relieved from 3 to 7 d after operation, and the pain almost disappeared 3 months after operation. The VAS score of 18 cases was 5.33±1.24 before surgery, 2.79±1.32 on the 3rd day, 1.86±1.21 on the 7th day, 0.86±0.93 on the 1st month, 0.33±0.48 on the 3rd month, and 0.09±0.29 on the 6th month after operation, and the difference was statistically significant ( F=58.50, P<0.001). There were no serious complications during and after operation, and the success rate of treatment (no recurrence of symptoms, no residual recurrence of imaging lesions, no serious complications after operation) was 100%. Conclusion:Treatment of osteoid osteoma with mini-open excision using burrs under the navigation of O-arm is a simple, safe, minimally invasive and efficient technique. Intraoperative precise positioning and the use of burr with navigation to remove a larger area than the tumor nest are the keys to successful treatment.

Objective:To explore the risk factors of recurrence after resection of thigh soft tissue malignant tumors and the evaluation of the postoperative lower limb function.Methods:A total of 211 patients who underwent thigh soft tissue malignant tumor resection in the Department of Orthopaedics of the second affiliated Hospital of Medical College of Zhejiang University from May 2011 to May 2021 were retrospectively analyzed, including 117 males and 94 females, aged 53 (43, 65) years. There were 59 cases of atypical/well-differentiated liposarcoma, 30 cases of other types of liposarcoma, 33 cases of malignant fibrous histiocytoma, 19 cases of fibrosarcoma, 12 cases of rhabdomyosarcoma, 12 cases of leiomyosarcoma, 9 cases of synovial sarcoma, and 37 cases of others. The tumor involvement of muscle, bone, blood vessel, nerve tissue and intermuscular compartment, postoperative Musculoskeletal Tumor Society (MSTS) functional score and recurrence were recorded. The relationship between anatomical structure and postoperative recurrence was analyzed by Cox logistic regression to determine risk factors; the cumulative recurrence rate of different compartment groups (medial compartment, anterior compartment, and posterior compartment) were compared; The Box plot was used to compare the postoperative function of patients with resection of different anatomical structures (e.g., vastus lateralis, biceps femoris, femur, etc.).Results:A total of 34 out of 211 patients relapsed, with a recurrence rate of 16.1%. The recurrence time ranged from 2.6 months to 91.6 months after operation, with a median recurrence time of 37.0 (18.2, 52.8) months. Three independent risk factors were found to be associated with recurrence, namely: pathological grade [ HR=3.86, 95% CI(1.75, 8.51)], involvement of vastus intermedius [ HR=3.05, 95% CI(1.53, 6.06)], and involvement of vastus medialis [ HR=3.17, 95% CI(1.56, 6.41)]. The recurrence rate of patients with anterior chamber tumor resection was 35.3%, which was higher than that of patients without tumor resection (16.2%), and the difference was statistically significant ( P=0.020). There was no significant difference in recurrence rate between patients with medial chamber tumor resection and patients without tumor resection ( P>0.05). The recurrence rate of patients with posterior compartment tumor resection was 12.3%, which was lower than that of unresectable patients (37.6%), and the difference was statistically significant ( P=0.002).The postoperative MSTS score of 167 patients averaged 26±3.2 points (9-30 points). After intraoperative resection of part of the femur, vastus intermedius, vastus medialis, and rectus femoris, the patient's function was relatively poor [corresponding median MSTS score: 25 (23, 28), 26 (24 28), 26 (24,28), 26(24, 27)]. Conclusion:The risk factors for local recurrence after resection of thigh soft tissue malignant tumors include: pathological grade of the tumor, and whether the vastus intermedius or vastus medialis is involved. Anterior compartment tumors have a higher recurrence rate after surgery. If the tumor involves the above-mentioned anatomical structures, more attention should be paid to the risk of local recurrence after surgery.

Objective:To clarify the clinicopathological, especially molecular, features of early-onset gastric cancer with the aim of informing analysis of treatment strategies.Methods:In this retrospective case-control study, we examined data from a dedicated gastric cancer database in Zhongshan Hospital affiliated to Fudan University. The original cohort comprised 2506 patients with gastric cancer who had undergone gastrectomy in Zhongshan Hospital Fudan University from July 2020 to October 2021, including 198 with early-onset gastric cancer (aged ≤45 years) and 2,308 with non-early gastric cancer. We used a simple random sampling method to select 396 of the 2,308 patients aged >45 years (ratio of 1:2) as the control group and then compared molecular diagnostic data and clinicopathological features of the two groups.Results:The median age was 39 years in the early-onset gastric cancer group, while 66 years in the control group. The clinicopathological features of early-onset gastric cancer included female predominance (59.1% [117/198] vs. 27.8% [110/396], χ 2=54.816, P<0.001), less comorbidity (32.3% [64/198] vs. 57.1% [226/396], χ 2=32.355, P<0.001), poorer differentiation (93.9% [186/198] vs. 74.5% [295/396], χ 2=30.777, P<0.001) and higher proportion of diffuse type (40.4% [80/198] vs. 15.9% [63/396], χ 2=69.639, P<0.001), distant metastasis (7.1% [14/198] vs. 2.8% [11/396], χ 2=6.034, P=0.014). Regarding treatment, distal gastrectomy was more commonly performed than proximal gastrectomy (55.1% [109/198] vs. 47.0% [186/396], 1.5% [3/198] vs. 8.3% [33/396], χ 2=11.644, P=0.003). Family history of gastric cancer, TNM stage, tumor size, lymph node dissection, nerve invasion, nodes harboring metastases, range of lymph node dissection, digestive tract reconstruction procedure, implementation of laparoscopic surgery, combined resection, and preoperative treatment did not differ significantly between the two groups (all P>0.05). Molecular diagnosis showed there was a smaller percentage of mismatch repair deficiency in the early-onset gastric cancer than in the control group (1.0% [2/198] vs. 10.1% [40/396], χ 2=16.301, P<0.001), and a higher rate of positivity for Claudin 18.2 (77.8% [154/198] vs. 53.0% [210/396], χ 2=5.442, P<0.001). HER-2 and Epstein–Barr virus positivity rates did not differ significantly between the two groups. Conclusion:Early-onset gastric cancer is a distinct type of gastric cancer with a high degree of malignancy, and treatment targeting Claudin 18.2 may be effective.

Objective:To clarify the clinicopathological, especially molecular, features of early-onset gastric cancer with the aim of informing analysis of treatment strategies.Methods:In this retrospective case-control study, we examined data from a dedicated gastric cancer database in Zhongshan Hospital affiliated to Fudan University. The original cohort comprised 2506 patients with gastric cancer who had undergone gastrectomy in Zhongshan Hospital Fudan University from July 2020 to October 2021, including 198 with early-onset gastric cancer (aged ≤45 years) and 2,308 with non-early gastric cancer. We used a simple random sampling method to select 396 of the 2,308 patients aged >45 years (ratio of 1:2) as the control group and then compared molecular diagnostic data and clinicopathological features of the two groups.Results:The median age was 39 years in the early-onset gastric cancer group, while 66 years in the control group. The clinicopathological features of early-onset gastric cancer included female predominance (59.1% [117/198] vs. 27.8% [110/396], χ 2=54.816, P<0.001), less comorbidity (32.3% [64/198] vs. 57.1% [226/396], χ 2=32.355, P<0.001), poorer differentiation (93.9% [186/198] vs. 74.5% [295/396], χ 2=30.777, P<0.001) and higher proportion of diffuse type (40.4% [80/198] vs. 15.9% [63/396], χ 2=69.639, P<0.001), distant metastasis (7.1% [14/198] vs. 2.8% [11/396], χ 2=6.034, P=0.014). Regarding treatment, distal gastrectomy was more commonly performed than proximal gastrectomy (55.1% [109/198] vs. 47.0% [186/396], 1.5% [3/198] vs. 8.3% [33/396], χ 2=11.644, P=0.003). Family history of gastric cancer, TNM stage, tumor size, lymph node dissection, nerve invasion, nodes harboring metastases, range of lymph node dissection, digestive tract reconstruction procedure, implementation of laparoscopic surgery, combined resection, and preoperative treatment did not differ significantly between the two groups (all P>0.05). Molecular diagnosis showed there was a smaller percentage of mismatch repair deficiency in the early-onset gastric cancer than in the control group (1.0% [2/198] vs. 10.1% [40/396], χ 2=16.301, P<0.001), and a higher rate of positivity for Claudin 18.2 (77.8% [154/198] vs. 53.0% [210/396], χ 2=5.442, P<0.001). HER-2 and Epstein–Barr virus positivity rates did not differ significantly between the two groups. Conclusion:Early-onset gastric cancer is a distinct type of gastric cancer with a high degree of malignancy, and treatment targeting Claudin 18.2 may be effective.

Objective:To retrospectively analyze the patients with spinal metastases who received surgical intervention and summarize the evolution of their clinical and pathological characteristics and surgical methods.Methods:The data of 703 patients with spinal metastases from January 2007 to December 2018 were collected retrospectively. There were 395 males (56.19%, 395/703) and 308 females (43.81%, 308/703) with an average age of 58.14±11.46 years (range 13-84 years). According to the degree of invasion and thoroughness of tumor resection, the surgical methods could be divided into minimally invasive surgery, decompression surgery, separation surgery, piecemeal resection and total en-bloc spondylectomy surgery. The operative methods were minimally invasive surgery in 89 cases (12.66%), decompression surgery in 96 cases (13.66%), separation surgery in 303 cases (43.10%), piecemeal resection in 182 cases (25.89%) and total en-bloc spondylectomy in 33 cases (4.69%). To analyze the trend of the clinical, pathological types and surgical treatment of patients with spinal metastases over the years, and determine the relevant factors affecting the decision-making of surgical methods by multivariate logistic regression.Results:The ratio of male to female was 1.28:1. 39.54% (278/703) of patients with single-segment involvement in 703 patients, 24.04% (169/703) of patients with double-segment metastasis and 36.42% (256/703) of patients with multi-segment metastasis. The most common type of primary tumor was lung cancer (34.57%, 243/703), followed by breast cancer (8.25%, 58/703), myeloma (8.11%, 57/703), gastrointestinal tumor (6.82%, 48/703) and renal malignant tumor (6.40%, 45/703). From 2007 to 2018, there was no significant difference in the percentage change of different age, gender and primary tumor source composition (age: χ 2=14.01, P=0.233; gender: χ 2=35.73, P=0.341; primary tumor: χ 2=120.09, P=0.074). The percentage of patients with sacrococcygeal metastasis decreased from 20.00% in 2008 to 1.89% in 2017 and the difference was statistically significant (χ 2=8.09, P=0.005). The percentage of patients with multi-level metastasis increased from 26.67% in 2008 to 52.83% in 2017, and the difference was statistically significant (χ 2=7.23, P=0.007). The percentage of patients with minimally invasive surgery decreased from 25.00% in 2007 to 5.88% in 2018, and the percentage of patients with segmented resection decreased from 53.33% in 2008 to 10.29% in 2018. The proportion of the two surgical methods showed a significant downward trend, and the differences were statistically significant (minimally invasive surgery: χ 2=1.46, P=0.026; segmented resection surgery: χ 2=19.56, P<0.001). The percentage of patients undergoing separation surgery increased from 13.33% in 2008 to 64.71% in 2018, and the proportion of patients undergoing total en-bloc spondylectomy increased from 0 in 2007 to 10.29% in 2018. Both surgical methods showed a significant growth trend and the differences were statistically significant (separation surgery: χ 2=27.09, P<0.001; χ 2=4.16, P=0.042). Multivariate Logistic regression analysis showed that age, metastatic site, number of metastatic segments, pathological vertebral fractures, Frankel grade, SINS score and VAS score were independent factors influencing surgical decision-making ( P<0.05). Conclusion:With different time and age, the invasiveness and thoroughness of surgery are increasing, which shows that the percentage of patients who underwent separation surgery and to-tal en-bloc spondylectomy is significantly increasing. Age, metastatic site, number of metastatic segments, pathological vertebral fractures, Frankel grade, SINS score and VAS score are independent factors affecting surgical decision-making.

Objective:To explore the clinical characteristics of dislocation after resection and reconstruction of tumors involving pelvic area II, and to try to propose intraoperative and postoperative techniques to prevent its occurrence.Methods:From March 2011 to March 2021, 122 patients with resection and reconstruction involving pelvic area II were retrospectively analyzed. Among them, 17 had postoperative dislocation, 32 had pelvic area II, and 31 had pelvic area I+II. There were 40 cases in the pelvic area II+III, and 19 cases in the pelvic area I+II+III. There were 49 female patients and 73 male patients; the mean age was 47 years (9-73 years). The Musculoskeletal Tumor Society (MSTS) score of lower extremity patients after reduction was evaluated, and the clinical characteristics of dislocation, such as dislocation direction, dislocation time and reduction method, were counted and analyzed, and feasible prevention measures were analyzed based on the imaging characteristics after resection and reconstruction. dislocation method.Results:Among the 122 patients, there were 17 cases of dislocation, and the dislocation rate was 13.7%. Among them, 12 cases were anterior dislocation, accounting for 70.6% of anterior dislocation; 5 cases were posterior dislocation, and the proportion of posterior dislocation was 29.4%, difference (χ 2=4.52, P=0.033). There were 12 cases of dislocation within 3 months after operation, accounting for 70.6%; 1 case of dislocation occurred in 5 months after operation, and the other 4 cases of dislocation occurred for more than one year. The MSTS score of the dislocation patients after reduction was 56.1±15.6% (20%-80%). Combined with postoperative imaging examinations, the feasible methods for preventing dislocation include: The anteversion angle of the acetabular cup can be appropriately reduced (0°-10°); The acetabular cup can be appropriately shifted to the rear of the rotation center; Appropriately reducing the anteversion angle of the femoral neck prosthesis, the combination of the three can reduce the occurrence of femoral-acetabular prosthesis impingement; at the same time, the affected limb is controlled in a neutral position with strict nail shoes after surgery to avoid the occurrence of external rotation. Conclusion:The dislocation after tumor resection and reconstruction in pelvic area II is mostly anterior dislocation. Postoperative CT scan of the pelvis shows that the space between the neck of the femoral stem prosthesis and the lower edge of the acetabulum is small, which is prone to impingement. If the anteversion angle of the acetabular cup is appropriately reduced, the acetabular prosthesis is appropriately displaced posteriorly, and the anteversion angle of the femoral neck is reduced by 5°, the possibility of femoral-acetabular impingement can be reduced, thereby reducing the risk of postoperative dislocation.