Epidemiological investigation and diagnostic analysis of osteonecrosis of the femoral head in three northeastern provinces of China

BACKGROUND

In this retrospective case investigation, we analysed the data of patients with osteonecrosis of the femoral head (ONFH) to reveal demographic and clinical diagnostic features of ONFH in three northeastern provinces of China and provide a reference for its prevention, diagnosis, and treatment.

METHODS

We collected data from patients in Beijing Orthopaedic Hospital of Liaoning, focusing on the aetiology and diagnosis of ONFH. Medical records and self-designed questionnaires were used to collect information for statistical analysis, including age, aetiology, reason for glucocorticoid use, hospital level at first visit, and diagnosis.

RESULTS

In total, 906 patients with complete medical records were included in the analysis. The mean patient age was 47.65 ± 12.12 years. The peak age distribution was in the 40s for men and the 50s for women. Among the total cohort, 72 patients (7.95%; 40 men and 32 women) had traumatic ONFH, 198 (21.85%; 131 men and 67 women) had steroid-induced ONFH, 230 (25.39%; 121 men and 109 women) had idiopathic ONFH, and 406 (44.81%; 397 men and 9 women) had alcohol-induced ONFH. Six hundred and twenty patients were diagnosed with ONFH at the first visit, while 286 patients were misdiagnosed, with a diagnosis rate of 68.43%. The diagnosis rate at the first visit in tertiary hospitals was 76.14%. The diagnosis rate at the first visit in second-class hospitals was 52.07%.ONFH was most likely to be misdiagnosed as lumbar disc herniation.

CONCLUSIONS

Most patients with ONFH in three northeastern provinces of China were middle-aged, male, and had alcohol-induced ONFH. The misdiagnosis rate of ONFH at the first visit was very high, especially for misdiagnosis of lumbar disc herniation, indicating that the diagnosis of ONFH requires further improvement.

Is there still an indication for the Birmingham Hip Resurfacing in femoral head osteonecrosis?

PURPOSE

Osteonecrosis of the femoral head (ONFH) is a progressive hip disease. Hip resurfacing arthroplasty (HRA) is a preferred surgical procedure among hip arthroplasty performed in young patients. The aim of this study is to show the long-term clinical and radiological results of HRA procedures performed for patients suffering from ONFH.

METHODS

Forty-five patients who underwent hip resurfacing with the diagnosis of femoral head osteonecrosis were included in the study. The Harris Hip Score (HHS) was used for clinical scoring of the patients. The blood chromium, cobalt, white blood cell (WBC) count, and CRP levels of patients were checked. Ultrasonography (USG) was performed for all patients at mid-term control checked for pseudo-tumours. For the radiological evaluation, acetabular inclination, stem shaft angle, prothesis-to-neck ratio, osteolysis zones, and heterotopic ossification were used.

RESULTS

The mean age of the patients was 46.6 ± 9.3 years, and the mean follow-up period was 11.83 ± 2.9 years. The mean HHS was 90.3 ± 12.8 for final follow-up. The mean WBC value was 8.2 109/L, mean CRP value was 6.3 mg/L, mean chromium value was 4.9 µg/L, and mean cobalt value was 1.8 µg/L. Inclination changing 0.2°(p = 0.788), stem shaft angle changing 0.7°(p = 0.424), and neck-to-prosthesis ratio changing 0.01°(p = 0.075). No pseudo-tumours were detected in any patients in USG examination.

CONCLUSION

HRA provides long-term implant survival and excellent clinical outcomes for end-stage ONFH patients with low complication rates.

Evaluation of the long-term patient-reported outcomes after hip arthroplasty or joint preserving with Sugioka femoral osteotomy in patients with femoral head osteonecrosis

PURPOSE

This study retrospectively evaluated long-term clinical outcomes and patient-reported outcome measures (PROMs) in patients with osteonecrosis of the femoral head (ONFH) who underwent transtrochanteric rotational osteotomy (TRO), curved varus osteotomy (CVO), and total hip arthroplasty (THA).

METHODS

We retrospectively reviewed the 109 hips in 96 patients (46 men, 50 women) who underwent CVO, TRO, or THA for ONFH treatment. The mean follow-up period for the TRO, CVO, and THA groups was 14.8, 11.5, and 13.3 years, respectively.

RESULTS

The THA conversion rate of the TRO patients was significantly higher than that of the patients with CVO, and the final clinical scores in the patients with TRO did not improve compared with preoperative scores. Postoperative PROMs showed that the total and pain scores of the patients with THA were significantly higher than those of patients with TRO and CVO, while the PROM score did not change between patients with TRO and CVO. The analysis further showed that the preoperative type C2, stage 3A, or postoperative type C1 and C2 were significant predictors of decreased final PROM scores.

CONCLUSION

This study found that CVO and THA are clinically effective treatments for ONFH, with significant improvements compared with preoperative scores. However, THA was associated with significantly higher PROMs and pain scores than those of CVO and TRO in long-term follow-up. Furthermore, our results suggest that postoperative PROMs depend mainly on the preoperative level of collapse and postoperative transposed intact ratio of the articular surface of the femoral head.

Intraoperative Epiphyseal Perfusion Monitoring Does Not Reliably Predict Osteonecrosis Following Treatment of Unstable SCFE

BACKGROUND

Avascular necrosis (AVN) remains the most dreaded complication of unstable slipped capital femoral epiphysis (SCFE) treatment. Newer closed reduction techniques (with perfusion monitoring) have emerged as a technically straightforward means to address residual SCFE deformity while still minimizing the risk of osteonecrosis. However, limited data exists regarding the reliability of intraoperative epiphyseal perfusion monitoring to predict the development of AVN. The purpose of this study was to evaluate its reliability.

METHODS

We retrospectively reviewed all patients with unstable SCFE who underwent closed or open reduction with epiphyseal perfusion monitoring using an intracranial pressure (ICP) probe from 2015 to 2023 at a single institution with a minimum 6-month radiographic follow-up. Demographic, clinical, and radiographic data were recorded, including duration of symptoms, type of reduction, capsulotomy performed, presence of a waveform on ICP monitoring after epiphyseal fixation, and development of AVN on follow-up radiographs.

RESULTS

Our cohort included 33 hips (32 patients), of which 60.6% (n=20) were male. The average age was 12.5±1.8 years, with a median follow-up of 15.8 months. Eleven hips were treated with open reduction using the modified Dunn technique (10 hips) or anterior approach (1 hip), and 22 hips were treated with inadvertent (5 hips) or purposeful closed reduction using the Leadbetter technique (17 hips). Overall, 8 of the 33 hips in our series (24.2%) developed AVN, 6 of which (20%) had a pulsatile waveform on intraoperative epiphyseal perfusion monitoring. The overall rate of AVN after closed reductions was 31.8% (7 of 22 hips); the incidence of AVN after closed reduction with a detectable waveform was 30% (6 of 20 hips). There was no significant association between time to surgery ( P =0.416) or type of reduction ( P =0.218) and the incidence of AVN.

CONCLUSIONS

In this series, intraoperative epiphyseal perfusion monitoring did not reliably predict the development of osteonecrosis. To our knowledge, this is the first study to report AVN after demonstrable intraoperative epiphyseal perfusion following closed reduction of unstable slips.

LEVEL OF EVIDENCE

Level IV: case series-therapeutic study.

Clinical efficacy of Femoral Neck System for treatment of unstable femoral neck fractures in young adults

OBJECTIVE

This study was performed to evaluate the mid-term clinical efficacy of the Femoral Neck System (FNS) (DePuy Synthes, Zuchwil, Switzerland) in treating young patients with unstable Pauwels type III femoral neck fractures.

METHODS

We performed a retrospective observational analysis of 21 young adults treated with the FNS. Clinical outcomes were assessed based on fracture reduction quality, Harris hip scores, and postoperative complication rates.

RESULTS

The study comprised 21 patients with a mean age of 35 years (range, 20-50 years) who were followed for a mean duration of 22.8 months (range, 16-30 months). Closed reduction was unfeasible in three (14.3%) patients, each of whom required open reduction. Notable postoperative complications were avascular necrosis in two (9.5%) patients, nonunion in one (4.7%), and implant failure in one (4.7%). Each of these complications led to the requirement for total hip arthroplasty.

CONCLUSION

The favorable mid-term clinical outcomes of this study indicate that the FNS is a potentially effective treatment modality for young individuals with unstable Pauwels type III femoral neck fractures.

Research progress in the pathogenesis of hormone-induced femoral head necrosis based on microvessels: a systematic review

Hormonal necrosis of the femoral head is caused by long-term use of glucocorticoids and other causes of abnormal bone metabolism, lipid metabolism imbalance and blood microcirculation disorders in the femoral head, resulting in bone trabecular fracture, bone tissue necrosis collapse, and hip dysfunction. It is the most common type of non-traumatic necrosis of the femoral head, and its pathogenesis is complex, while impaired blood circulation is considered to be the key to its occurrence. There are a large number of microvessels in the femoral head, among which H-type vessels play a decisive role in the "angiogenesis and osteogenesis coupling", and thus have an important impact on the occurrence and development of femoral head necrosis. Glucocorticoids can cause blood flow injury of the femoral head mainly through coagulation dysfunction, endothelial dysfunction and impaired angiogenesis. Glucocorticoids may inhibit the formation of H-type vessels by reducing the expression of HIF-1α, PDGF-BB, VGEF and other factors, thus causing damage to the "angiogenesis-osteogenesis coupling" and reducing the ability of necrosis reconstruction and repair of the femoral head. Leads to the occurrence of hormonal femoral head necrosis. Therefore, this paper reviewed the progress in the study of the mechanism of hormone-induced femoral head necrosis based on microvascular blood flow at home and abroad, hoping to provide new ideas for the study of the mechanism of femoral head necrosis and provide references for clinical treatment of femoral head necrosis.

Automatic planning and geometric analysis of the drilling path in core decompression surgery for osteonecrosis of the femoral head

BACKGROUND AND OBJECTIVE

Core decompression surgery is an effective treatment method for patients with pre-collapse osteonecrosis of the femoral head (ONFH). The treatment relies on accurately predrilling the wire into the necrotic lesion. However, the surgical planning of this drilling path remains unclear. This paper aims to develop a framework to automatically plan the drilling path and analyze its geometric parameters.

METHODOLOGY

The proposed system consists of two stages. The first stage is to detect the key points. Besides the entry point and target point for the drilling path, the center of the femoral head (FH) and the boundary points of the necrotic lesion are also detected for the subsequent geometric analysis. In the second stage, the geometric parameters of the drilling path are analyzed, including the size of the necrotic lesion, the length from the entry point to the target point, the relative location between the FH center and the necrosis center, and the angular range of the drilling path in the anterior-posterior (AP) direction and superior-inferior (SI) direction.

RESULTS

All of the drilling paths designed by the proposed system were considered successful, starting from the proximal subtrochanteric region, terminating at the center of the necrotic lesion, and remaining within the femoral neck. The relative coordinates of the centers of the femoral head and necrotic lesion were (-0.89,5.14,2.63) mm for the left femurs and (1.55,5.92,2.63) mm for the right femurs, on average. The angular range of the drilling path was 39.99±29.58 degrees in the SI direction and 46.18±40.73 degrees in the AP direction.

CONCLUSION

This study develops a framework that allows for automatic planning and geometric analysis of the drilling path in core decompression surgery. The target point of the drilling path primarily resides in the lateral-anterior-superior region relative to the femoral head center. Surgeons and researchers can benefit from our unified framework while still maintaining the flexibility to adapt to variations in surgical cases.

Risk factor analysis of femoral avascular necrosis after operation for Tönnis grade IV developmental dysplasia of the hip

PURPOSE

We explored the risk factors for avascular necrosis (AVN) after surgery using open reduction, pelvic osteotomy, and femoral osteotomy for Tönnis grade IV developmental dysplasia of the hip (DDH).

METHODS

In this retrospective study, we collected data of patients with Tönnis grade IV DDH treated with open reduction and pelvic osteotomy combined with femoral osteotomy from January 2012 to May 2020. The patients were divided into the AVN group and non-AVN group using the Kalamchi-MacEwen classification system. The clinical and imaging data of the two groups were collected, and the possible risk factors were included in the analysis. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors and odds ratios of AVN.

RESULTS

In all, 254 patients (mean age; 2.6±0.9 years, 278 hips) were included. The mean follow-up time was 3.8±1.5 years. A total of 89 hips (32%) were finally classified as AVN (Kalamchi-MacEwen II-IV). Univariate analysis showed significant associations with AVN for age (p=0.006), preoperative femoral neck anteversion (FAV) (p<0.001), femoral osteotomy length to dislocation height ratio (FDR) <1 (p<0.001), and the epiphyseal ossific nucleus diameter to the neck diameter ratio (ENR) <50% (p=0.009). Multivariate logistic regression analysis showed that only excessive preoperative FAV (OR: 1.04; 95% CI: 1.02-1.05; p<0.001) and FDR<1 (OR: 3.58; 95% CI: 2.03-6.31; p<0.001) were independent risk factors for femoral head necrosis.

CONCLUSION

Excessive preoperative FAV and FDR<1 are important risk factors for femoral AVN after open reduction, pelvic osteotomy, and femoral osteotomy for Tönnis grade IV DDH. For children with DDH with high dislocation and excessive FAV, clinicians should fully evaluate their condition and design more personalized treatment programs to prevent AVN.

[Correlation analysis between combined deflection angle and osteonecrosis of femoral head after femoral neck fracture]

Objective

To evaluate the correlation between pelvic incidence (PI) angle, hip deflection angle (HDA), combined deflection angle (CDA) and osteonecrosis of the femoral head (ONFH) after femoral neck fracture, in order to explore early predictive indicators for ONFH occurrence after femoral neck fracture.

Methods

A study was conducted on patients with femoral neck fractures who underwent cannulated screw internal fixation between December 2018 and December 2020. Among them, 208 patients met the selection criteria and were included in the study. According to the occurrence of ONFH, the patients were allocated into ONFH group and non-NOFH group. PI, HDA, and CDA were measured based on the anteroposterior X-ray films of pelvis and axial X-ray films of the affected hip joint before operation, and the differences between the two groups were compared. The receiver operating characteristic curve (ROC) was used to evaluate the value of the above imaging indicators in predicting the occurrence of ONFH.

Results

Among the 208 patients included in the study, 84 patients experienced ONFH during follow-up (ONFH group) and 124 patients did not experience ONFH (non-ONFH group). In the non-ONFH group, there were 59 males and 65 females, the age was 18-86 years (mean, 53.9 years), and the follow-up time was 18-50 months (mean, 33.2 months). In the ONFH group, there were 37 males and 47 females, the age was 18-76 years (mean, 51.6 years), and the follow-up time was 8-45 months (mean, 22.1 months). The PI, HDA, and CDA were significantly larger in the ONFH group than in the non-ONFH group ( P<0.05). ROC curve analysis showed that the critical value of PI was 19.82° (sensitivity of 40.5%, specificity of 86.3%, P<0.05); the critical value of HDA was 20.94° (sensitivity of 77.4%, specificity of 75.8%, P<0.05); and the critical value of CDA was 39.16° (sensitivity of 89.3%, specificity of 83.1%, P<0.05).

Conclusion

There is a correlation between PI, HDA, CDA and the occurrence of ONFH after femoral neck fracture, in which CDA can be used as an important reference indicator. Patients with CDA≥39.16° have a higher risk of ONFH after femoral neck fracture.

Is COVID-19 an independent risk factor for the development of avascular necrosis of the hip? A retrospective study to evaluate the factors associated with avascular necrosis of the hip in patients who had COVID-19 infection

PURPOSE

The cumulative effect of hyper-coagulative COVID-19 disease and using steroids leads to increased avascular necrosis (AVN) hip incidence. This study aims to correlate the various factors of COVID-19 infection with the occurrence of AVN hip.

METHODS

It is a retrospective cross-sectional study of non-traumatic AVN hip patients with a history of COVID-19 infection. A total number of 50 patients satisfied the inclusion criteria. The following details were obtained: (a) patient's demographics, (b) COVID-19: interval of infection and groin pain, duration of symptoms, severity, steroid intake, (c) AVN hip: involved side, Ficat-Arlet staging.

RESULTS

The mean age was 36.3 years (range: 20-60), and body mass index (BMI) was 25.13 kg/m2 (range: 18.50-31.50). There were 45 males and five females. Sixty percent (30) of patients managed at home, 24% (12) required admission into the ward, 2% (1) were in ICU only, and 14% (7) admitted to both ICU and ward. The mean interval of COVID-19 infection and onset of hip pain was 359.02 days (range: 10-822 days). Thirty-eight percent (19) patients required steroids (injection and oral), 46% (23) took steroids (oral only), whereas 16% (8) recovered without steroids. The stage of AVN correlated with the severity of COVID-19 infection (p-value -0.038) and significant improvement in VAS and HHS after treatment in each stage. The mean follow-up was 9.79 months (6-19 months).

CONCLUSION

A low-dose steroid intake with moderate to severe COVID-19 infection produces an additive effect on the development of AVN hip. Most affected individuals were adult males, and stage II AVN was the most common, managed with bisphosphonates and core decompression for short intervals.

Effects of the location of both anterior and lateral boundaries of the necrotic lesion on collapse progression in osteonecrosis of the femoral head

BACKGROUND

The location of the lateral boundary of the necrotic lesion to the weight-bearing portion of the acetabulum (Type classification) is an important factor for collapse in osteonecrosis of the femoral head (ONFH). Recent studies also reported the significance of the location of the anterior boundary of the necrotic lesion on the occurrence of collapse. We aimed to assess the effects of the location of both anterior and lateral boundaries of the necrotic lesion on collapse progression in ONFH.

METHODS

We recruited 55 hips with post-collapse ONFH from 48 consecutive patients, who were conservatively followed for more than one year. Using a plain lateral radiograph (Sugioka's lateral view), the location of the anterior boundary of the necrotic lesion to the weight-bearing portion of the acetabulum was classified as follows: Anterior-area I (two hips) occupying the medial one-third or less; Anterior-area II (17 hips) occupying the medial two-thirds or less; and Anterior-area III (36 hips) occupying greater than the medial two-thirds. The amount of femoral head collapse was measured by biplane radiographs at the onset of hip pain and each follow-up period, and Kaplan-Meier survival curves with collapse progression (≥1 mm) as the endpoint were produced. The probability of collapse progression was also assessed by the combination of Anterior-area and Type classifications.

RESULTS

Collapse progression was observed in 38 of the 55 hips (69.0%). The survival rate of hips with Anterior-area III/Type C2 was significantly lower. Among hips with Type B/C1, collapse progression occurred more frequently in hips with Anterior-area III (21 of 24 hips) than in hips with Anterior-area I/II (3 of 17 hips, P < 0.0001).

CONCLUSIONS

Adding the location of the anterior boundary of the necrotic lesion to Type classification was useful to predict collapse progression especially in hips with Type B/C1.

Pathological fracture increases the risk of unsatisfactory functional results and avascular necrosis in children with proximal femur simple bone cysts

INTRODUCTION

Proximal femur simple bone cysts (SBCs) are rare in children, but with a risk of pathological fractures and the associated poor outcomes. This study aimed to evaluate the functional and radiographic outcomes of children with proximal femur SBCs.

PATIENTS AND METHODS

38 children with proximal femur SBCs treated surgically at our department, West China hospital, were enrolled in the study. Patients were divided into two groups according to whether pathological fractures presented before treatment. The non-fracture group received treatment of open curettage, cavity electrocauterization, bone grafting, and fixation (proximal femoral plate, intramedullary nail or Kirschner wire). The pathological fracture group received the same procedures of curettage, electrocauterization, grafting, and fixation. Autogenous iliac bone grafting was done in all cases, and the artificial bone was used as a supplementary based on the size of the cavity. Postoperatively, all patients underwent hip spica or similar orthosis immobilization for six weeks and received the same rehabilitation program after the removal of hip spica. Patients were evaluated by two independent observers, including the functional results based on the Ratliff's criteria, avascular necrosis, healing rate based on the Neer scoring system, coxa vara, and premature physeal arrest. We described the good outcome in Ratliff's criteria as "Satisfactory results", and fair and poor outcomes as "Unsatisfactory results." Grade 1 and grade 2 Neer results were termed as failures in treatment, and grades 3 and 4 were considered successes and healing.

RESULTS

38 patients with 38 hips (18 on the left side and 20 on the right side) were evaluated, including 9 females and 29 males, with a mean age of 9.0±2.6 years old (range, 5 to 14 years). There was no significant difference between these two groups in the baseline data of gender, age, side, grafting, staging, and fixation methods. The rate of unsatisfactory functional results in the pathological fractures group was 56.3% (9/16), significantly higher than that in patients without fracture (22.7%, 5/22. p= 0.047). There was also a significant difference in avascular necrosis of the femoral head between the pathological fractures group (7/16) and the group without fracture (2/22, p=0.021). Thirty cases presented with healing, including 13 in the fractures group and 17 in the non-fracture group (p=1.000), and eight cases were graded as failures (2 cases of grade 1 and 6 cases of grade 2). There were also no significant differences between these two groups in premature physeal arrest (2 in fracture group and 1 in non-fracture group, P=0.562), and Coxa vara (3 in the fracture group and 0 in non-fracture group, P=0.066).

CONCLUSIONS

Pathological fracture significantly increases the risk of unsatisfactory functional results and avascular necrosis of the femoral head in patients with femoral neck SBCs. Prophylactic treatment and fixation of SBCs in weight bearing proximal femur region is better to manage without complications than managing with pathological fractures.

Analysis of the natural collapse course of non-traumatic osteonecrosis of the femoral head based on the matrix model

BACKGROUND

There are many predictions about the progression of natural collapse course of osteonecrosis of the femoral head. Here, we aimed to combine the three classical prediction methods to explore the progression of the natural collapse course.

METHODS

This retrospective study included 127 patients admitted to our hospital from October 2016 to October 2017, in whom the femoral head had not collapsed. Logistic regression analysis was performed to determine the collapse risk factors, and Kaplan-Meier survival curves were used for femoral head survival analysis. The collapse rate of the femoral head was recorded within 5 years based on the matrix model. The specificity of the matrix model was analyzed using the receiver operating characteristic curve.

RESULTS

A total of 127 patients with a total of 202 hips were included in this study, and 98 hips collapsed during the follow-up period. Multivariate logistics regression analysis showed that the predictive ability of the matrix model was stronger than Association Research Circulation Osseous staging, Japanese Investigation Committee classification, and area (P < 0.05). Kaplan-Meier survival curve showed that the median survival time of femoral head in patients was 3 years. The result of the receiver operating characteristic curve analysis showed that the area under the curve (AUC) of the matrix model had better predictive value (AUC = 0.771, log-rank test: P < 0.001).

CONCLUSION

We creatively combined the three classical prediction methods for evaluating the progression of the natural collapse course based on the matrix model and found that the higher the score of the matrix model, the higher the femoral head collapse rate. Specifically, the matrix model has a potential value in predicting femoral head collapse and guiding treatment selection.

Femoral neck system versus multiple cannulated screws for the fixation of Pauwels classification type II femoral neck fractures in older female patients with low bone mass

BACKGROUND

Femoral neck fractures in older adult patients are a major concern and often necessitate surgical intervention. This study compared the clinical outcomes of 2 surgical techniques: the femoral neck system (FNS) and cannulated compression screws (CCSs).

METHODS

A total of 40 female patients (mean age 73.50 ± 11.55 years) with femoral neck fractures of Pauwels classification type II and receiving surgical fixation between 2020 and 2022 were enrolled. The patients were categorized into an FNS group (n = 12) or a CCS group (n = 28), and surgical duration, intraoperative blood loss, length of hospital stay, and incidence of postoperative adverse events were analyzed.

RESULTS

No significant intergroup differences in demographic characteristics were discovered. The mean surgical duration for all patients was 52.88 ± 22.19 min, with no significant difference between the groups. However, the FNS group experienced significantly higher intraoperative blood loss (P = 0.002) and longer hospital stay (P = 0.023) than did the CCS group. The incidence of osteonecrosis was higher in the CCS group, whereas the incidence of nonunion or malunion was higher in the FNS group. The surgical method did not appear to be a significant risk factor. The main risk factor for revision surgery was longer duration until the first adverse event (P = 0.015).

CONCLUSION

The FNS does not appear to provide superior surgical outcomes compared with CCSs in older adult women with Pauwels classification type II femoral neck fractures. A longer duration between surgical fixation and the first adverse event before stabilization of the fracture site may be a risk factor for revision surgery.

Coxa Magna following treatment of developmental dysplasia of the hip: investigation for associated potential factors

Coxa Magna (CM) is defined as a condition in which the horizontal (transverse) diameter of the femoral head is larger on the affected side than on the intact side. CM can occur as a manifestation of avascular necrosis (AVN) following treatment for the developmental dysplasia of the hip (DDH). Alternatively, it can also be secondary to other hip disorders, such as Perthes' disease. This study aimed to determine the prevalence and indicators of CM and AVN of the femoral head that can be detected during follow-up in patients with unilateral DDH treated with closed reduction (CR) or open reduction (OR) surgery. The files of 143 patients treated for unilateral DDH between January 1997 and December 2017 were reviewed retrospectively. A total of 104 patients, including Group 1 ( n = 49) patients who underwent CR under general anesthesia and Group 2 ( n = 55) patients who underwent OR were included in the study. CM; It was considered as the case where the femoral head was 15% or more larger than the intact side. A total of 104 patients were followed up for 77.27 ± 13.96 months, with a mean age of 15.43 ± 7.76 months. When Group 1 and Group 2 were compared, there was no statistical difference in terms of sex, side, adductor tenotomy, and AVN ( P > 0.05). CM developed in 22.4% ( n = 11) of the patients in Group 1 and in 49.1% ( n = 27) in Group 2, and the difference was statistically significant ( P = 0.008). When the effect of independent variables on the development of CM is evaluated with the multivariate logistic regression model, the risk of developing CM is 3474 times higher in those who underwent iliopsoas tenotomy compared with those who did not. The primary outcome of this study is that CM is more frequent in patients treated with OR for DDH. CM may be a nonpathological condition that occurs in connection with iliopsoas tenotomy or surgical treatment. Prospective studies with a larger number of cases, designed to minimize confounding factors, are required.

[Avascular necrosis of the hip secondary to long-standing COVID]

Long COVID is a term used to describe the long-terms effects of COVID-19 infection that continue for weeks or months after the patient has recovered from COVID-19. Long COVID is defined by the persistence of symptoms beyond 12 weeks from the onset of the disease. Corticosteroids are part of the treatment in this period with good results in controlling the disease; however, it is a predisposing factor for the development of avascular necrosis. We present a clinic case of a young man of 39 years old with diagnosis of avascular necrosis in his left hip, before the administration of corticosteroids for the treatment of COVID-19. There is a lack of consensus about the dosage and duration of steroids required to develop avascular necrosis. Some authors have reported that cumulative dose of 2,000 mg prednisone (or its equivalent) was required for avascular necrosis development. For patients with advanced avascular necrosis stages total hip arthroplasty is an attractive option with excellent outcomes in terms of pain relief and survivorship.

The Duration of Hardware Retention After Radiologic Union of Surgically Treated Femoral Neck Fractures in Children May Predict the Aggravation or Occurrence of Avascular Necrosis of the Femoral Head or Neck After Hardware Removal

BACKGROUND

The incidence of aggravation or occurrence of avascular necrosis (AVN) following hardware removal in surgically treated pediatric femoral neck fractures who achieved radiologic consolidation is unknown. This study aimed to investigate the risk factors for this complication.

METHODS

Seventy-one pediatric (mean age: 9.8±3.9 y) were retrospectively analyzed. Risk factors (age, sex, laterality, severity of initial displacement, type of fracture, time from trauma to reduction, reduction and fixation method, quality of reduction, time required to achieve radiologic union, duration of hardware retention, presence of AVN before hardware removal and follow-up time) were recorded. The severity of AVN was assessed based on radiographs with Ratliff's classification.

RESULTS

Following hardware removal, the aggravation/occurrence of AVN was detected in 11 hips (15.5%). Among the 5 hips (7%) with aggravation of AVN, 1 (1.4%) with type II AVN and 3 (4.2%) with type III AVN exhibited aggravation of type I AVN, while the remaining hip (1.4%; type I) showed enlargement of the involved AVN area. Six hips (8.5%) developed AVN following hardware removal: 2 (2.8%) were classified as type I and 4 (5.6%) as type III. Receiver operating characteristic curve analysis indicated that hardware retention >7 months after union is associated with a decreased rate of aggravation or occurrence of AVN of the femoral neck or head following hardware removal.

CONCLUSIONS

The incidence of aggravation or occurrence of AVN following hardware removal in surgically treated pediatric femoral neck fractures is 15.5%; hardware retention >7 months after radiologic union may reduce the risk of aggravation or occurrence of AVN of the femoral neck or head postimplant removal.

LEVEL OF EVIDENCE

Level III.

Sclerosis rim volume ratio and Japanese Investigation Committee classification as predictive factors for femoral head collapse progression after non-vascularized fibular grafting in osteonecrosis patients

OBJECTIVE

The purpose of this retrospective cohort study was to determine the relationship between sclerosis rim volume ratio (SVR) and the progression of femoral head collapse after non-vascularized fibular grafting (NVFG) surgery in patients with osteonecrosis of the femoral head (ONFH), investigating risk factors associated with femoral head collapse progression and establishing a predictive model to enhance clinical decision-making.

METHODS

ONFH patients who underwent NVFG between January 2008 and December 2021 were analyzed retrospectively to assess the risk of post-operative collapse progression (collapse >2 mm). A logistic regression model was used to evaluate the independent risk factors associated with collapse progression, including age, sex, etiology, affected side, Japanese Investigation Committee classification (JIC), and the sclerosis rim volume ratio (SVR). SVR values was collected from three weight-bearing columns, namely SVR1, SVR2, and SVR3, respectively.

RESULTS

57 patients with 64 hips who had undergone NVFG and were followed up for at least one year were included. During the follow-up, collapse＞2 mm occurred in 30 hips (46.88%). Multivariable analysis revealed that JIC (p =0.037) and SVR1 (p = 0.04) were independent risk factors for collapse progression after NVFG. The results of the receiver operating characteristic (ROC) analysis indicated that the aforementioned indices provided a satisfactory prediction of early femoral head collapse progression in ONFH patients after NVFG. The regression model using the above two indicators as a composite index showed satisfactory performance in predicting early postoperative femoral head collapse progression, with an area under the curve (AUC) of 84.6%.

CONCLUSIONS

SVR is significant predictor of post-operative collapse progression following NVFG, and the composite index provides an optimal predictive value for femoral head collapse progression after surgery.

3D printing-assisted total hip arthroplasty and internal fixation for the treatment of fresh acetabular fracture and femoral head necrosis: A case report

RATIONALE

Posterior wall comminuted fractures of the acetabulum are typically caused by high-energy trauma, and the complex anatomical structure of the acetabulum makes their treatment challenging. However, reports of the treatment of fresh acetabular fractures combined with femoral head necrosis are extremely rare.

PATIENT CONCERNS

A 57-year-old male, injured in a car accident, presented with right hip pain and limited mobility. At the age of 50, the patient was diagnosed with avascular necrosis of the right femoral head, experiencing right hip pain and a limp while walking, for which conservative treatment was initiated.

DIAGNOSIS

The patient was clinically diagnosed with fresh comminuted posterior wall acetabular fracture and late-stage femoral head necrosis.

INTERVENTIONS

We applied 3D printing technology and computer-assisted virtual surgical techniques for preoperative planning, simulated fracture reduction, and designed personalized bone plates and screws for fixation of the posterior wall of the acetabulum. A single-stage total hip arthroplasty was performed to treat femoral head necrosis.

OUTCOMES

He began walking with the assistance of a walker 1 month after surgery, and at 6 months post-surgery, the acetabular posterior wall fracture had effectively healed, allowing the patient to return to work.

LESSONS

The application of 3D printing technology in acetabular internal fixation and total hip arthroplasty is helpful for fracture assessment, facilitates smooth surgery, promotes fracture reduction and healing, restores hip joint function, and ensures a high level of safety.

Incidence and risk factors for osteonecrosis of the femoral head in five hundred and ten sickle cell disease paediatric patients

PURPOSE

Osteonecrosis of the femoral head (ONFH) is a degenerative and progressive disorder that mainly affects people with sickle cell disease (SCD). Herein, we aimed to search for a better understanding of markers that can act as risk factors for ONFH in patients with SCD.

METHODS

We conducted a retrospective study including 510 SCD patients followed over 23 years. Patients were divided into the ONFH group and the no-ONHF control group. Univariate and multivariate logistic regression analyses were performed to identify risk factors.

RESULTS

Among 510 SCD patients, 41(8%) were diagnosed with ONFH at a mean age of 167 months ± 64 (72-288). The cumulative incidence of ONHF increased from 2.3% at ten years to 18.3% at 20 years of age. The radiological grade 3 ONHF was predominant. No significant differences in sex, age at diagnosis of SCD, and Hb genotype were found between groups. The patient age and the time since diagnosis of SCD were statistically higher in patients with ONHF in univariate and multivariate analysis. ONHF was also associated with higher creatinine level (p = 0.001) lower LDH level (p = 0.006), and higher number of vaso-occlusive crisis (VOC)/patient/year (p < 0.001). The cumulative incidence of ONHF in patients having more than 3 VOC/year was significantly higher (43% versus 18.9% at 20 years, p < 0.001). In addition, infections, gallstones, growth delay, delayed initiation of hydroxyurea, and a higher transfusion rate were significantly associated with ONFH.

CONCLUSION

These findings confirm that ONFH is closely related to the age, severity, and duration of SCD. Better management of this disease prevents acute and chronic complications, and early screening of the ONFH as soon as the first signs of the severity of the disease are detected provides a better functional prognosis.

Did the COVID-19 Pandemic Coincide With an Increase in Osteonecrosis as Indication for Total Hip Arthroplasty in Older Patients?

BACKGROUND

Osteonecrosis of the femoral head is a common indication for total hip arthroplasty (THA). It is unclear to what extent the COVID-19 pandemic has impacted its incidence. Theoretically, the combination of microvascular thromboses and corticosteroid use in patients who have COVID-19 may increase the risk of osteonecrosis. We aimed to (1) assess recent osteonecrosis trends and (2) investigate if a history of COVID-19 diagnosis is associated with osteonecrosis.

METHODS

This retrospective cohort study utilized a large national database between 2016 and 2021. Osteonecrosis incidence in 2016 to 2019 was compared to 2020 to 2021. Secondly, utilizing a cohort from April 2020 through December 2021, we investigated whether a prior COVID-19 diagnosis was associated with osteonecrosis. For both comparisons, Chi-square tests were applied.

RESULTS

Among 1,127,796 THAs performed between 2016 and 2021, we found an osteonecrosis incidence of 1.6% (n = 5,812) in 2020 to 2021 compared to 1.4% (n = 10,974) in 2016 to 2019; P < .0001. Furthermore, using April 2020 to December 2021 data from 248,183 THAs, we found that osteonecrosis was more common among those who had a history of COVID-19 (3.9%; 130 of 3,313) compared to patients who had no COVID-19 history (3.0%; 7,266 of 244,870); P = .001).

CONCLUSION

Osteonecrosis incidence was higher in 2020 to 2021 compared to previous years and a previous COVID-19 diagnosis was associated with a greater likelihood of osteonecrosis. These findings suggest a role of the COVID-19 pandemic on an increased osteonecrosis incidence. Continued monitoring is necessary to fully understand the impact of the COVID-19 pandemic on THA care and outcomes.

Spontaneous femoral neck fracture resulting from osteonecrosis involving lateral femoral head-neck junction: a retrospective study

BACKGROUND

Spontaneous femoral neck fracture is a rare condition that remains controversial due to limited reported cases. This retrospective study aims to provide further insights into the etiology and characteristics of the disease.

METHOD

We conducted a retrospective review of data from 963 patients with femoral neck fractures. The data encompassed demographic information, medical histories, radiographic records, bone mineral density (BMD) measurements, and pathological examinations. Patients were categorized into two groups: spontaneous femoral neck fracture (SFF) group (30 cases) and control group (933 cases), based on their medical histories. Logistic regression analysis was employed to identify risk factors for SFF. Statistical analysis was performed to compare and elucidate the characteristics of SFF within each group.

RESULTS

Logistic regression analysis revealed osteonecrosis of the femoral head, steroid use, and osteoporosis as three significant risk factors for SFF. Furthermore, a higher proportion of Garden type I and II fractures, as well as Pauwels type I fractures, were observed in the SFF group compared to the control group. Within the SFF group, a higher proportion of patients with osteonecrosis exhibited Garden type III and IV fractures compared to those with osteoporosis. Additionally, both magnetic resonance imaging (MRI) and pathological examinations demonstrated that osteonecrosis in the SFF group predominantly occurred at the lateral femoral head-neck junction.

CONCLUSIONS

Osteonecrosis of the femoral head, particularly involving the lateral head-neck junction, was confirmed as a major risk factor for SFF. Furthermore, SFF exhibits internal heterogeneity based on its different causes.

Bone marrow edema of the hip: a narrative review

Bone marrow edema (BME) of the hip is a radiological-clinical condition with symptoms ranging from asymptomatic to severe, and it is characterized by increased interstitial fluid within the bone marrow, usually at the femur. Depending on the etiology it can be classified as primary or secondary. The primary cause of BME is unknown, while the secondary forms include traumatic, degenerative, inflammatory, vascular, infectious, metabolic, iatrogenic, and neoplastic etiologies. BME could be classified as reversible or progressive. Reversible forms include transient BME syndrome and regional migratory BME syndrome. Progressive forms include avascular necrosis of the femoral head (AVNH), subchondral insufficiency fracture, and hip degenerative arthritis. The diagnosis can be difficult, because at the beginning, the outbreak of hip pain, typically acute and disabling without any prior trauma or exceptional physical activity, is poorly supported by radiographic findings. MRI is the gold standard, and it shows an area of intermediate signal on T1-weighted MRI scans and a high signal on T2-weighted scans, usually lacking sharps margins. In the reversible form, BME is typically self-limiting, and it can be managed conservatively by means of pharmacological and physical therapy. Surgery is generally required for progressive forms in patients who failed non-operative treatment, and it ranges from femoral head and neck core decompression to total hip arthroplasty.

Femoral neck fracture after femoral head necrosis: a case report and review of the literature

INTRODUCTION

Pathological fractures of the femoral neck caused by necrosis of the femoral head are extremely rare. Here, we report a rare case of bilateral femoral head osteonecrosis extending to the femoral neck, with bilateral pathological fractures of the femoral neck occurring within a short period of time.

CASE REPORT

A 65-year-old male with a 25-year history of daily consumption of 750 ml of liquor, presented with right hip pain after labor for 1 month. He subsequently sustained a right femoral neck fracture without trauma and underwent a right total hip arthroplasty. Two months later, he suffered a non-traumatic left femoral neck fracture and underwent a left total hip arthroplasty. Histopathological examination revealed osteonecrosis of the femoral head and neck, along with the presence of osteoclasts and granulomatous inflammation. Bone mineral density testing also showed osteoporosis. The bilateral femoral neck fractures were ruled out to be caused by any other pathological factors.

DISCUSSION

This is the first report of pathological fractures of the bilateral femoral neck caused by femoral head necrosis. During the literature review process, we found that this case conforms to the histological characteristics of rapidly destructive hip disease and analyzed the etiology of femoral head necrosis and the pathogenesis of femoral neck fractures.

Laboratory indices in patients with osteonecrosis of the femoral head: a retrospective comparative study

BACKGROUND

Osteonecrosis of the femoral head is a degenerative condition linked to corticosteroids, alcoholism, or trauma. With its rising prevalence due to increased hormone drug use and its debilitating effects on young to middle-aged individuals, understanding its association with specific laboratory indicators can aid early diagnosis and prevention.

METHODS

Upon retrospective analysis of the clinical data pertaining to individuals diagnosed with femoral head necrosis, spanning from January 2016 to January 2022, a comprehensive evaluation was conducted within the same time frame. The study aimed to ascertain the presence of femoral head necrosis in a total of 1176 individuals. A total of 1036 healthy patients were recruited randomly, ensuring that their ages matched. The risk variables associated with the utilization of logistic regression analysis and analysis techniques are employed. The patient examines the age distribution within a specific age group.

RESULTS

The levels of high-density lipoprotein, low-density lipoprotein A1, lipoprotein B1, total protein, albumin, globulin, and other lipophilic metabolism and coagulation markers exhibited a statistically significant increase compared to the control group. A multifactor logistic regression analysis was conducted to identify potential risk factors associated with femoral head necrosis in patients.

CONCLUSION

Femoral head necrosis is associated with a range of variables including coagulation malfunction, lipid metabolic abnormalities, and inflammation.

Complete Repair of Osteonecrosis of the Femoral Head After Basicervical Femoral Neck Rotational Osteotomy: A Case Report

CASE

We present a 28-year-old female patient who developed left hip pain and was diagnosed with osteonecrosis of the femoral head (ARCO stage II). The patient underwent a basicervical femoral neck rotational osteotomy (BFNRO) combining surgical hip dislocation technique and extended retinacular soft-tissue flap technique. She was followed up for 53 months and exhibited complete repair of the necrotic area, with normal hip range of motion, gait, and excellent hip functional scores.

CONCLUSION

The BFNRO procedure, by rotating the necrotic area of the femoral head out of the weight-bearing zone, has the potential to achieve complete repair of the necrotic area.

High-degree posterior rotational osteotomy for extensive collapsed femoral head osteonecrosis in teenagers: remodeling and results with a mean of 10-year follow-up

INTRODUCTION

This study evaluated the effectiveness of high-degree posterior rotational osteotomy for teenagers with extensively collapsed femoral head osteonecrosis.

MATERIALS AND METHODS

We reviewed 40 hips in 35 patients with severely collapsed femoral head osteonecrosis treated by this procedure with a mean follow-up period of 9.7 years (range 5-25 years). Thirteen hips had a history of steroid administration. Nine had slipped capital femoral epiphysis. Nine had femoral neck fracture. Two had traumatic dislocation and fracture. Seven had no apparent risk factors. The mean age of the patients (18 women and 17 men) was 14.8 years. All femoral heads were extensively collapsed below the acetabular roof, and 20 hips showed preoperative joint space narrowing (ARCO stage 4). Lateral radiographs of the femoral head revealed extensive lesions from the posterior to anterior portion. The mean degree of posterior rotation was 118° with intentional varus positioning [mean: 19° (range 10-30)]. The pre- and postoperative extent of the viable area of the femoral head was assessed using conventional anteroposterior radiographs and 45-degree flexion radiography. Further collapse, joint space narrowing, femoral head morphology, and congruency with the acetabulum based on the Stulberg classification were assessed using conventional anteroposterior radiographs. The clinical assessment was conducted using the Merle d'Aubigné hip scores at the last follow-up.

RESULTS

The viable area of the femoral head on the loaded portion was seen during a short period after operations. The necrotic lesions were gradually improved postoperatively. The mean extent of viable bone below the acetabular roof was 48% at less than 6 months after surgery and 92% at the final follow-up. The mean extent on 45° flexion radiography was 54% at less than 6 months after surgery and 89% at the final follow-up. Further collapse was prevented in 38 hips (95%). In 19 of 20 hips with preoperative narrowing of the joint space, the joint space was first improved, but narrowing progressively observed in 9 of 40 hips at the final follow-up. Thirty-four hips had excellent or good clinical outcomes, whereas 6 had fair or poor outcomes.

CONCLUSIONS

We concluded that this procedure is effective at delaying the progression of degeneration if adequate area of viable bone can be moved under the loaded portion of the acetabulum in teenagers with severe femoral head osteonecrosis.

The association between three-dimensional measurement of posterior tilt angle in impacted femoral neck fractures and osteonecrosis of the femoral head

BACKGROUND

Hollow screw internal fixation is commonly used in clinical treatment of impacted femoral neck fractures. Previous studies have demonstrated a correlation between the preoperative posterior tilt angle of the femoral head and failure of internal fixation, but there are fewer studies related to the occurrence of postoperative femoral head necrosis and the posterior tilt angle.

METHODS

To examine the relationship between three-dimensional posterior tilt angle measurements in affected femoral neck fractures and postoperative osteonecrosis of the femoral head and related risk variables. We retrospectively examined 130 Yantaishan Hospital patients with affected femoral neck fractures from 2019 to 2022. Three-dimensional reconstruction technology assessed the posterior tilt angle of the femoral head and separated patients into necrosis and non-necrosis groups based on postoperative femoral head necrosis. Univariate analysis compared clinical data between groups, and multivariate logistic regression analyzed risk variables for femoral head necrosis. Postoperative femoral head necrosis was predicted by posterior tilt angle using Receiver operating characteristic (ROC) curve analysis.

RESULTS

Out of 130 patients who were followed up for 16-68 months postoperatively, 20 developed femoral head necrosis. Multivariate logistic regression analysis indicated that the posterior tilt angle and reduction quality level C were risk factors for the occurrence of femoral head necrosis. The ROC curve analysis showed that the three-dimensional measurement of the posterior tilt angle had predictive value for postoperative femoral head necrosis, with a cut-off value of 20.6°.

CONCLUSIONS

These results suggest that, for patients with impacted femoral neck fractures, the posterior tilt angle and reduction quality level C are risk factors for femoral head necrosis following closed reduction and internal fixation surgery. Fracture patients with a posterior tilt angle ≥ 20.6°are more likely to experience postoperative femoral head necrosis.

[A case of total hip arthroplasty for femoral head necrosis while using satralizumab for neuromyelitis optica spectrum disorders]

A 47-year-old woman developed right femoral head necrosis during long-term steroid use for neuromyelitis optica spectrum disorder. She underwent a total hip arthroplasty because her right hip pain persisted after satralizumab treatment. There were no postoperative infections. Under oral administration of tacrolimus 3 mg, prednisolone 11 mg, and acetaminophen 2,275 mg, her postoperative body temperature was less than 38°C and normalized in about 2 days after the operation. No parameters indicating worsening of inflammation were observed in the blood test. In satralizumab-treated patients, infection cannot be ruled out even without inflammatory findings. In particular, if a slight fever of the 37°C-range or a mildly high white blood cell count persists, paying attention to signs of infection and actively investigating the presence or absence of infection using medical image diagnostic devices are necessary.

A Molecular Troika of Angiogenesis, Coagulopathy and Endothelial Dysfunction in the Pathology of Avascular Necrosis of Femoral Head: A Comprehensive Review

Avascular necrosis of the femoral head (ANFH) is a painful disorder characterized by the cessation of blood supply to the femoral head, leading to its death and subsequent joint collapse. Influenced by several risk factors, including corticosteroid use, excessive alcohol intake, hypercholesterolemia, smoking and some inflammatory disorders, along with cancer, its clinical consequences are thrombus formation due to underlying inflammation and endothelial dysfunction, which collaborates with coagulopathy and impaired angiogenesis. Nonetheless, angiogenesis resolves the obstructed free flow of the blood by providing alternative routes. Clinical manifestations of early stage of ANFH mimic cysts or lesions in subchondral bone, vasculitis and transient osteoporosis of the hip, rendering it difficult to diagnose, complex to understand and complicated to cure. To date, the treatment methods for ANFH are controversial as no foolproof curative strategy is available, and these depend upon different severity levels of the ANFH. From an in-depth understanding of the pathological determinants of ANFH, it is clear that impaired angiogenesis, coagulopathy and endothelial dysfunction contribute significantly. The present review has set two aims, firstly to examine the role and relevance of this molecular triad (impaired angiogenesis, coagulopathy and endothelial dysfunction) in ANFH pathology and secondly to propose some putative therapeutic strategies, delineating the fact that, for the better management of ANFH, a combined strategy to curtail this molecular triangle must be composed rather than focusing on individual contributions.

Femoral Head Core Decompression and Bone Marrow Concentrate Injection in Pediatric Sickle-cell Related Avascular Necrosis

BACKGROUND

Femoral head avascular necrosis affects 10% to 40% of patients with sickle cell disease (SCD). The purpose of this study was to evaluate the results of femoral head core decompression and bone marrow aspirate concentrate (CD-BMAC) injection in pediatric patients with SCD.

METHODS

Eligible patients were enrolled in this retrospective study of patients undergoing CD-BMAC. Patients with SCD who were younger than 18 at the time of surgery and had >1 year of follow-up were included in this analysis. Hips were staged based on the Ficat system by 2 raters. The visual analog score for pain, hip outcome score, modified Harris hip score, and the University of California, Los Angeles activity score were used as patient-reported outcome measures preoperatively, at 5 to 9 months postoperatively, and final follow-up. Treatment failure was defined as total hip arthroplasty or visual analog score >3 at the final follow-up.

RESULTS

Twenty-three hips in 17 patients were included, with a median age at the time of surgery of 15.8 years (interquartile range: 13.1 to 17.8 y). Patients were followed for 4.25 ± 1.7 years. Ten hips showed a 1-stage increase in the Ficat stage at the final follow-up, whereas 11 retained the same stage, and 1 hip had a 1-stage regression. All patient-reported outcome measures showed significant improvement from the preoperative visit to short-term follow-up, but the preoperative to final follow-up improvement was not significant. Six treatment failures were recorded, including 3 total hip arthroplasties and 3 painful hips at the final follow-up. In a multivariate logistic regression model, only skeletal maturity (odds ratio = 16.2, 95% CI: 1.44-183.0, P = 0.024) and femoral head collapse (odds ratio = 12.0, 95% CI: 1.1-130.5, P = 0.041) were significant predictors of treatment failure.

CONCLUSIONS

In the largest study on pediatric SCD patients undergoing CD-BMAC, we found that CD-BMAC injection offers significant improvement in pain and functional outcomes in the short term, with a very low risk for complications. Skeletal maturity and femoral head collapse were significant predictors of treatment failure. Patients with a collapsed femoral head experienced functional deterioration over time after initial improvement, whereas precollapse hips maintained their functional improvement up to the latest follow-up.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Can Rigid Femoral Nailing Be Used for Pediatric Femoral Shaft Fracture in Children 8 to 10 Years? Use of RIN in Patients With Femoral Shaft Fracture

BACKGROUND

The treatment modalities for pediatric femoral shaft fractures are determined by their age, weight, and fracture pattern. Rigid intramedullary nailing (RIN) is usually recommended for patients >11 years of age, and elastic intramedullary nailing (EIN) has been used for patients under 10 years. However, little is known about the use of RIN in patients aged 8 to 10 years. We examined the differences in patients with femoral shaft fractures who were treated with EIN or RIN in terms of (1) fracture healing; (2) changes of anatomic parameters; and (3) related complications.

METHODS

We retrospectively reviewed 54 patients between 8 and 10 years of age, with femoral shaft fractures, who were treated with either EIN or RIN between 2011 and 2020. Lateral trochanteric entry was used for RIN procedure. The mean follow-up period was 26.4 months (range, 6 to 113 mo). There were 17 patients in the EIN group and 37 patients in the RIN group. The mean age at the time of surgery was 1 year younger in the EIN group ( P <0.01). The mean weight of the patient was significantly heavier in the RIN group compared with the EIN group.

RESULTS

Complete union of the fracture was achieved slightly faster in the RIN group at 3.4 months compared with 3.7 months in the EIN group ( P =0.04). There were no clinically significant changes of the anatomic parameters in either group, including neck shaft angle and articulotrochanteric distance. There was no evidence of avascular necrosis at the time of final follow-up for either group. There were no significant differences in postoperative complications between the groups.

CONCLUSION

RIN using lateral trochanteric entry is a feasible surgical option for femoral shaft fractures in patients 8 to 10 years of age that are heavier than 40 kg or with unstable fracture patterns.

LEVEL OF EVIDENCE

Level III, retrospective cohort study. See the Guidelines for Authors for a complete description of levels of evidence.

Radiological manifestation of avascular necrosis (AVN) in sickle cell disease (SCD): a review of diagnostic imaging

Symptomatic avascular necrosis (AVN) imposes a higher risk for acute care consumption in adults living with SCD. Symptomatic AVN, have higher rates of visits to the emergency department, higher rates of admissions, and longer lengths of stay in hospitals. Properly timed diagnosis and early interventions can reduce morbidity and enhance the quality of life in these patients. Vaso-occlusion secondary to sickling leads to osteonecrosis of the joint/bone (AVN, dactylitis) and invites infection (osteomyelitis and septic arthritis). Understanding and awareness of the imaging features related to this major morbidity complication are essential for early diagnosis and prompt management. In about half of the patients with SCD, AVN can lead to chronic pain, particularly in the head of the femur and humerus. Humeral and femoral head AVN tend to be linked with each other.  Vertebral bone compression and collapse secondary to AVN have also been reported.  The diagnosis of AVN must be accurate, as the condition is complex requiring specific treatment according to the grade of bone and joint involvement. There are several classifications or staging systems used for grading bone and joint involvement. Knowledge of the image patterns and grade of affection in different joints and bones and the degree of progression of AVN lesions can markedly improve management decisions on AVN-specific surgical versus non-surgical interventions and improve patient outcomes. The aim of this report is to summarize the different imaging techniques and their role in the proper/early diagnosis and follow up of patients with AVN with detailed examples of the common sites involved.

[Risk factors for osteonecrosis of femoral head after femoral neck fracture fixation with femoral neck system]

Objective

To explore the risk factors for osteonecrosis of the femoral head (ONFH) after treatment of femoral neck fractures with femoral neck system (FNS).

Methods

Between January 2020 and February 2021, 179 patients (182 hips) with femoral neck fractures treated by FNS fixation were selected for retrospective analysis. There were 96 males and 83 females with an average age of 53.7 years (range, 20-59 years). There were 106 cases of low-energy-induced injury and 73 cases of high-energy-induced injury. The fractures were classified as type Ⅱ in 40 hips, type Ⅲ in 78 hips, and type Ⅳ in 64 hips according to Garden classification standard, and as typeⅠin 23 hips, type Ⅱ in 66 hips, and type Ⅲ in 93 hips according to Pauwels classification standard. There were 21 patients with diabetes. Patients were divided into ONFH group and non-ONFH group according to whether ONFH occurred at last follow-up. The data of the patients were collected, including age, gender, body mass index (BMI), trauma mechanism, bone mineral density, having diabetes or not, Garden classification and Pauwels classification of fractures, fracture reduction quality, femoral head retroversion angle, and removal of internal fixator or not. The above factors were analyzed by univariate analysis, and then multivariate logistic regression analysis was used to identify risk factors.

Results

Total 179 patients (182 hips) were followed up 20-34 months (mean, 26.5 months). Of these, 30 cases (30 hips) developed ONFH at 9-30 months after operation (ONFH group), and the incidence of ONFH was 16.48%. And 149 cases (152 hips) had no ONFH at last follow-up (non-ONFH group). The univariate analysis showed that there were significant differences between groups in bone mineral density, having diabetes or not, Garden classification, femoral head retroversion angle, and fracture reduction quality ( P<0.05). The multivariate logistic regression analysis showed that the Garden type Ⅳ fracture, reduction quality of grading Ⅲ, femoral head retroversion angle >15°, complicated with diabetes were the risk factors for ONFH after FNS fixation ( P<0.05).

Conclusion

For the patients with Garden type Ⅳ fracture, poor quality of fracture reduction, femoral head retroversion angle >15°, and diabetes, the risk of ONFH after FNS fixation increases.

Skeletal Outcomes in Children and Young Adults with Glomerular Disease

BACKGROUND

Children with glomerular disease have unique risk factors for compromised bone health. Studies addressing skeletal complications in this population are lacking.

METHODS

This retrospective cohort study utilized data from PEDSnet, a national network of pediatric health systems with standardized electronic health record data for more than 6.5 million patients from 2009 to 2021. Incidence rates (per 10,000 person-years) of fracture, slipped capital femoral epiphysis (SCFE), and avascular necrosis/osteonecrosis (AVN) in 4598 children and young adults with glomerular disease were compared with those among 553,624 general pediatric patients using Poisson regression analysis. The glomerular disease cohort was identified using a published computable phenotype. Inclusion criteria for the general pediatric cohort were two or more primary care visits 1 year or more apart between 1 and 21 years of age, one visit or more every 18 months if followed >3 years, and no chronic progressive conditions defined by the Pediatric Medical Complexity Algorithm. Fracture, SCFE, and AVN were identified using SNOMED-CT diagnosis codes; fracture required an associated x-ray or splinting/casting procedure within 48 hours.

RESULTS

We found a higher risk of fracture for the glomerular disease cohort compared with the general pediatric cohort in girls only (incidence rate ratio [IRR], 1.6; 95% CI, 1.3 to 1.9). Hip/femur and vertebral fracture risk were increased in the glomerular disease cohort: adjusted IRR was 2.2 (95% CI, 1.3 to 3.7) and 5 (95% CI, 3.2 to 7.6), respectively. For SCFE, the adjusted IRR was 3.4 (95% CI, 1.9 to 5.9). For AVN, the adjusted IRR was 56.2 (95% CI, 40.7 to 77.5).

CONCLUSIONS

Children and young adults with glomerular disease have significantly higher burden of skeletal complications than the general pediatric population.

Does Diabetes Mellitus Increase the Risk of Avascular Osteonecrosis? A Systematic Review and Meta-Analysis

Avascular osteonecrosis (AVN) is caused by the disrupted blood supply to the bone. Most AVN cases occur in the femoral head, but other sites might be affected as well, including the jaw or distal bones of the extremities. Previous studies suggested that diabetes could increase the risk of AVN of the jaw, but the relationship between diabetes and AVN in other bone sites is unclear. This systematic review and meta-analysis aimed to summarize the evidence from studies that had reported on the occurrence of AVN in sites other than the jaw, depending on the diagnosis of diabetes. Overall, we included 6 observational studies carried out in different populations: primary or secondary AVN of the femoral head, Takayasu arteritis, general population, kidney transplant recipients, systemic lupus erythematosus, and primary brain tumors. A random-effects meta-analysis showed that the risk of AVN in sites other than the jaw was non-significantly increased in patients with diabetes (odds ratio: 1.90, 95% confidence interval: 0.93-3.91). The pooled estimate increased and was significant after the exclusion of one study (2.46, 1.14-5.32). There was a significant heterogeneity (I² = 65%, tau² = 0.48, p = 0.01; prediction interval, 0.21-16.84). There was no significant publication bias (p = 0.432). In conclusion, diabetes could increase the risk of AVN in sites other than the jaw, but the available evidence is limited. There is a need for large, well-designed, population-based studies.

An overview of pathophysiology and treatment options of osteonecrosis of femoral head in sickle cell disease

Osteonecrosis of the femoral head (ONFH) is the most prevalent musculoskeletal pathologic manifestation of sickle cell disease (SCD) resulting in an osteonecrotic event. This review aimed to summarize mechanisms involved in pathophysiology of ONFH and treatment options available in Saudi Arabia to treat SCD patients with complication of osteonecrotic event. The pathophysiology of ONFH include genetic and micro particles involvement. The progression of osteonecrosis involves reduced levels of bioactive compounds in peripheral blood mononuclear cells and elevated CD4+T circulating levels to stimulate pro-inflammatory cytokines contributing to inflammation at target site. Initial treatment approach is pharmacological agents use to mitigate risk. Further, bone morphogenetic protein stimulation initiate bone formation and treatment can be improved with the use of bone morphogenetic protein, total hip arthroplasty and cell therapies. This review provides baseline information for future studies to be carried out in Saudi Arabia to improve treatment options in SCD patients with ONFH.

Clinical Effect of Open Reduction and Internal Fixation for Femoral Neck Fracture in Young Adults and Related Factors of Femoral Head Necrosis

Objective

The purpose of this article is to analyze the clinical effect of open reduction and internal fixation on femoral neck fracture in young adults and to explore the related factors of femoral head necrosis.

Methods

The subjects were young and middle-aged femoral neck fracture patients admitted to our hospital from July 2019 to July 2021. 90 patients were randomly divided into two groups according to different treatment methods. The control group (n = 45) was treated with open reduction and internal fixation with hollow nails, while the observation group (n = 45) was treated with closed reduction and internal fixation with hollow nails. The clinical effects and adverse reactions of the two groups and the risk factors of avascular necrosis of femoral head were analyzed.

Results

Compared with the control group, the operation time of the observation group was significantly shortened (P < 0.05), the amount of bleeding during the operation was significantly reduced (P < 0.05), and the incidence of total adverse reactions was significantly reduced (P < 0.05). The HSS score and Harris score of the two groups were significantly decreased after treatment (P < 0.05), but there was no significant difference in the above scores between the two groups before and after treatment (P > 0.05). The related risk factors of necrosis included gender, Garden classification, time from injury to operation, and time of weight bearing after operation (P < 0.05) but not related to age and cause of injury (P > 0.05).

Conclusion

Open and closed reduction and internal fixation can effectively treat femoral neck fracture in young adults. The risk factors of adverse reactions of osteonecrosis include gender, Garden classification, time from injury to operation, and weight-bearing time after operation.

Risk Factors for Avascular Necrosis After Closed Reduction for Developmental Dysplasia of the Hip

BACKGROUND

Avascular necrosis (AVN) is a major complication after closed reduction for developmental dysplasia of the hip. The factors that predispose to AVN remain controversial. The purpose of this study was to analyze the risk factors, especially patient factors, such as age at reduction, grade of dislocation, and ossific nucleus development, related to AVN.

MATERIALS AND METHODS

We retrospectively reviewed children with dysplasia of the hip treated by closed reduction between 1997 and 2006. AVN was evaluated using Salter criteria and Kalamchi and MacEwen classification. Related factors were analyzed.

RESULTS

One hundred and eight children (140 hips) with an average age of 16.6 months at closed reduction (range: 6-24 mo) were included in the study. For an average duration of 10.1 years (range 7-16 y) of follow-up, 44 hips (31.4%) developed AVN. Grade II or higher AVN occurred in 14 hips (10%). The incidence of AVN increased with the grade of dislocation ( P =0.022) and underdevelopment of the ossific nucleus ( P <0.001). Underdevelopment of the ossific nucleus was also found to be positively correlated with the dislocation grade ( P =0.047). The age at the time of reduction, sex, and side were not significant factors. Children who underwent secondary operation were all older than 1 year at reduction.

CONCLUSIONS

High-grade dislocation correlates with the underdevelopment of the ossific nucleus. Patients with these 2 characteristics are predisposed to AVN. As underdevelopment of the ossific nucleus occurred regardless of age, it is not advisable to delay reduction because it does not alter the AVN rate, and instead, it increases the secondary operation rate.

LEVEL OF EVIDENCE

Level IV case series.

Management of Avascular Necrosis (AVN) of Femoral Head by Core Decompression with Tensor Fascia Lata (TFL) Muscle Pedicle Bone Graft

Avascular necrosis (AVN) of femoral head is an increasingly common cause of musculoskeletal disability. Most of the cases caused by steroid induced and traumatic but idiopathic cause are not also uncommon. Almost all the patients presented with pain at the hip, limping gait, restricted movement and difficulty in waking and squatting and becomes disabled. Core decompression and muscle pedicle bone graft at stage IIA, IIB and III provides painless and mobile life. Core decompression supplemented with bone graft to enhance mechanical support and augment healing. We have started a prospective study for the treatment of AVN of Femoral head at stage IIA, IIB and III by core decompression and Tensor fascia lata muscle pedicle bone graft in the department of Orthopaedic surgery Bangabandhu Seikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2009 to December 2019. Aim of the study was to assess the effectiveness of core decompression and tensor fascia lata muscle pedicle bone graft in the treatment of AVN of femoral head at stage IIA, IIB and III. A total 48 patients and 65 hips were operated. Out of 48 patients, male was 30(62.50%) and female was 18(37.5%). Male-Female ratio was 1.66:1. Age of the patients ranging from 20 years to 50 years, mean age 36±4.65 years. According to aetiology corticosteroid induced was 47/65 (72.31%), idiopathic was 8(12.31%), post traumatic was 4(6.15%), ITP was 2(3.08%), ALL was 2(3.08%), and alcohol induced was 2(3.08%) of femoral head involvement. According to Ficat and Arlet's staging, stage IIA hip involvement was 28/65(43.08%), stage IIB was 32(49.23%) and stage III was 5(07.69%). All patients were treated with core decompression along with tensor fascia lata (TFL) muscle pedicle bone graft. All patients were followed clinically and radiologically at regular interval. Follow up period was 6 months to 10 years. Harris hip score (HHS) was used for evaluation of clinical outcome. Among the 65 hips, 24(36.92%) was excellent outcome (HHS >90), 30(46.15%) was good outcome (HHS: 80-90), 7(10.78%) was fair outcome (HHS: 70-79) and 4(6.15%) was poor outcome. For valid statistical analysis excellent and good results were grouped as satisfactory that was 54(83.07%) and fair and poor results were grouped as unsatisfactory that was11(16.93%), p value is <0.001 that is significant. It has been concluded that core decompression and TFL muscle pedicle bone graft is a pain relieving, head preserving procedure and improve hip function for the management of AVN of femoral head in stage IIA, IIB and III.

The Risk of Avascular Necrosis Following the Stabilization of Femoral Neck Fractures: A Systematic Review and Meta-Analysis

Background: Avascular necrosis (AVN) of the femoral head often requires surgical treatment and is often associated with femoral neck fractures. We conducted a systematic review and meta-analysis of recent research on the risk of AVN following the stabilization of fractured femoral neck with implants in PubMed. We assessed the effect of age on AVN incidence among patients aged > 50 and younger, depending on fracture type, Garden stage, Pouwels degree, Delbet stage, and age category. We followed PRISMA guidelines. Relevant studies were defined as research articles describing real-world studies reporting on the risk of AVN following primary surgical fracture stabilization with implants, published between 1 January 2011 and 22 April 2021. Fifty-two papers met the inclusion criteria, with a total of N = 5930 with surgically managed fractures. The pooled mean AVN incidence was significantly higher among patients with displaced fractures (20.7%; 95% CI: 12.8−28.5%) vs. those with undisplaced fractures (4.7%; 95% CI: 3.4−6.0%). No significant correlation was observed between AVN incidence weighted by sample size and time interval from injury to surgery (p = 0.843, R2 = 0.01). In conclusion, the risk of AVN following femoral neck fractures was generally high, especially in patients with displaced fractures. The time from injury to surgery did not correlate with AVN incidence.

The role of internal fixation in the treatment of femoral head necrosis with ipsilateral hip fracture

Whether internal fixation or hip arthroplasty is the most appropriate initial treatment for patients with ipsilateral hip fracture and osteonecrosis of the femoral head remains unknown. In this study, the prognoses of patients who underwent internal fixation or hip arthroplasty were analyzed and compared to explore the role of internal fixation in treating such patients. We retrospectively reviewed 69 patients diagnosed with osteonecrosis of the femoral head and ipsilateral hip fracture from 1999 to 2018. They were divided into the hip arthroplasty or internal fixation group. The visual analog scale and Harris score were used. The incidence of complications and the conversion to arthroplasty were also investigated to further explore the role of internal fixation. Male patients (male/female: 25/31 vs 20/38, P = .015), younger patients (average age: 46.80 ± 13.14 vs 61.07 ± 15.61, P < .001), and patients with femoral neck fractures (fracture type, femoral neck/trochanter: 21/31 vs 12/38, P = .003) were more likely to receive 1-stage hip arthroplasty. Of 38 patients undergoing internal fixation, fracture nonunion was identified in 9, and progression of osteonecrosis was identified in 16. Meanwhile, conversion to secondary hip arthroplasty occurred in 13 patients. Four independent risk factors for conversion to secondary hip arthroplasty were identified: age of ≤60 years (odds ratio [OR] = 9.786, 95% confidence interval [CI] = 2.735-35.015), male sex (OR = 6.790, 95% CI = 1.718-26.831), collapse of the femoral head before injury (OR = 7.170, 95% CI = 2.004-25.651), and femoral neck fracture (OR = 8.072, 95% CI = 2.153-30.261). A new scoring system was constructed for predicting conversion to hip arthroplasty in patients undergoing internal fixation treatment. A cutoff of ≤2 points indicated low risk for conversion, 3 to 4 points indicated moderate risk, and ≥5 points indicated high risk. Patients who underwent internal fixation had worse prognoses than those who underwent 1-stage hip arthroplasty. However, in this study, hip arthroplasty conversion did not occur in most patients who received internal fixation. Using the new scoring system to identify patients who may require conversion to replacement may help make appropriate patient management and clinical decisions.

Avascular necrosis under different treatment in children with developmental dysplasia of the hip: a network meta-analysis

The objective of this study was to evaluate the incidence of avascular necrosis (AVN) of the femoral head in children less than 3 years of age with developmental dysplasia of the hip (DDH) treated with closed reduction, open reduction alone and open reduction combined with osteotomy. We reviewed clinical trials from the PubMed, EMBASE and Cochrane Library databases (up to November 2020) that were related to closed reduction, open reduction alone and open reduction combined with osteotomy for the treatment of children under 3 years of age with DDH. The screening and quality evaluation of the literature were performed independently by two researchers. In case of disagreement, a third researcher resolved the discourse. Finally, the data were extracted, and the R software and GeMTC program package were used to conduct a network meta-analysis (NMA). The evaluation index was the incidence of AVN. Fourteen articles were included. The NMA showed that in terms of the incidence of AVN, cases treated with open reduction alone were higher than those with closed reduction, and the difference was statistically significant. Open reduction alone had the highest probability (94.4%) of having the highest incidence of AVN, followed by open reduction combined with osteotomy (5.5%) and closed reduction (0.1%). In the treatment of children with DDH who are younger than 3 years old, open reduction alone is most likely to be the treatment with the highest incidence of AVN, followed by open reduction combined with osteotomy. The closed reduction had the smallest probability of AVN.

Avascular Necrosis of Femoral Head-Overview and Current State of the Art

Avascular necrosis (AVN) of the femoral head is caused by disruption of the blood supply to the proximal femur. The alterations in the blood supply may occur following a traumatic event or result from a non-traumatic cause. Femoral neck fracture and hip dislocation and associated surgical procedures, corticosteroid therapy, and alcohol abuse frequently lead to AVN development. Type of fracture (displaced or undisplaced) and time between injury and surgery are the most critical factors in assessing the risk of developing AVN. Diagnosis of AVN can be established based on patients’ complaints, medical history, and radiographic findings. There is no consensus on the treatment of patients with AVN to date. Non-surgical methods are dedicated to patients in the early pre-collapse stages of the disease and consist of pharmacotherapy and physiotherapy. Surgery is recommended for patients with advanced disease.

Rapid and Severe Idiopathic Aseptic Necrosis of the Contralateral Femoral Head after Unilateral Total Hip Arthroplasty

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a multifactorial disease, and agnogenic ONFH, otherwise known as idiopathic ONFH, is rare in clinic. Idiopathic ONFH that exhibits severe necrosis and progresses extremely rapidly is called rapidly destructive hip disease (RDHD). RDHD greatly affects patients but is rarely reported in clinical practice and literature.

CASE PRESENTATION

In this study, a 64-year-old male patient with complete collapse and necrosis of the right femoral head complicated with severe bone destruction at 10 months after left total hip arthroplasty (THA) was reported. The period from the intact structure of the right femoral head to the first discovery of its complete collapse, according to imaging results, was 7 months. The duration from the occurrence of symptoms in the right hip joint to the first discovery of complete collapse and necrosis of the femoral head was only 5 months. At present, the cause has not been determined based on medical history, symptoms, signs, imaging evaluation results, laboratory examination results, and pathological examination results, though it has been identified as severe idiopathic aseptic necrosis of the femoral head with rapid progression, or RDHD. Finally, right THA was performed, and a good outcome was observed in the patient at present.

CONCLUSIONS

As a rare hip joint disease, RDHD greatly influences the normal life of patients. RDHD of the contralateral side after unilateral THA is even scarcer. Left THA may be one of the important factors accelerating the necrosis of the right femoral head. Hopefully, with this case report, more attention will be paid to the contralateral hip joint in patients undergoing unilateral THA by clinicians and rehabilitation physicians, and a clinical reference will be provided for the research on RDHD.

Evaluation of avascular necrosis risk factors after closed reduction for developmental dysplasia of the hip before walking age

Avascular necrosis (AVN) of the femoral head is one of the most important complications after closed reduction and spica cast application in developmental dysplasia of the hip (DDH) treatment. This study aims to put forth the impact of closed reduction age and other factors which can cause AVN. Inclusion criteria of the study were: closed reduction and spica cast application before walking age (12 months) and minimum 2 years duration of follow-up. The presence of femoral head ossific nucleus, International Hip Dysplasia Institute (IHDI) score, acetabular indices and AVN were evaluated from radiographies. Hip abduction angles were evaluated on CT images. The absence of the ossific nucleus at the closed reduction time and preoperative IHDI grade were not significant risk factors for AVN (respectively OR = 2.83; 95% CI, 0.99-8.07; P = 0.052; OR = 2.5; 95% CI, 0.85-7.32; P = 0.094). For the patients older than 10 months, (1) the absence of the ossific nucleus was a significant risk factor for grade 2 or higher AVN according to the Bucholz Ogden criteria (P = 0.020) and (2) the higher preoperative IHDI grade (IHDI 3-4) was a significant risk factor for AVN (P = 0.032). AVN of the femoral head was a significant risk factor for fair or poor clinical outcome (P = 0.001). It is not reasonable to wait for radiological visibility of the ossific nucleus to prevent femoral head AVN before applying closed reduction and spica cast, irrespective of the age interval.

[Femoral head necrosis rate and risk factors after internal fixation of femoral neck fracture:a Meta-analysis]

OBJECTIVE

To study the incidence and risk factors of osteonecrosis of the femoral head (ONFH) after internal fixation in adult patients with femoral neck fracture (FNF) after 2000, and identify high-risk population of ONFH.

METHODS

PubMed, Medline, The Cochrane Library, CNKI, Wanfang and VIP Database were searched to collect all the literatures on ONFH and related risk factors after internal fixation of FNF from January 1th 2000 to July 1th 2020. Study extraction was performed according to inclusion and exclusion criteria. Endnote X9 and Excel 2019 were used for literatures extraction, management and data entry, and R Studio 3.6.5 software was used for Meta-analysis. Subgroup analysis, sensitivity analysis and publication bias detection were used to explore the sources of heterogeneity and the reliability of the evaluation results.

RESULTS

A total of 16 studies with 5521 patients were included. Meta-analysis showed that the incidence of ONFH after internal fixation for adult FNF was 14.5% [95% CI(0.126-0.165)]. Fracture displacement[OR=0.27, 95%CI(0.21-0.35)] and reduction quality [OR=0.15, 95%CI(0.09-0.27)] were related risk factors for ONFH. The results of subgroup rate analysis showed that the non-displaced fracture necrosis rate was 6.2%[95%CI(0.051-0.077)] and the displaced fracture necrosis rate was 20.4% [95%CI(0.166-0.249)];the good reduction fracture necrosis rate was 8.3%[95%CI(0.072-0.095)] and the poor reduction fracture necrosis rate was 35.5%[95%CI(0.233-0.500)]. The included literatures have good consistency and no publication bias.

CONCLUSION

After 2000, the total incidence of ONFH after internal fixation of adult FNF has decreased, while the necrosis rates of patients with displaced fracture and poor reduction are still at a high level. The interval between injury and surgery was not analyzed in this study because of the inconstant division in the original literature.