OBJECTIVE: To evaluate precise assessment methods for predicting the optimal acetabular cup size in total hip arthroplasty (THA). METHODS: A clinical data of 73 patients (80 hips) who underwent primary THA between December 2022 and July 2024 and met the inclusion criteria was analyzed. There were 39 males and 34 females with an average age of 66.3 years (range, 56-78 years). Among them, 66 cases were unilateral THA and 7 were bilateral THAs. There were 29 patients (34 hips) of osteoarthritis, 35 patients (35 hips) of femoral neck fractures, and 9 patients (11 hips) of osteonecrosis of the femoral head. Based on anteroposterior pelvic X-ray films, three methods were employed to predict acetabular cup size, including preoperative template planning, radiographic femoral head diameter (FHD) measurement, and intraoperative FHD measurement. The predicted acetabular cup sizes from these methods were compared with the actual implanted sizes. RESULTS: The predicted acetabular cup sizes using the preoperative template planning, radiographic FHD measurement, and intraoperative FHD measurement were (51.25±2.81), (49.72±3.11), and (49.90±2.74) mm, respectively, compared to the actual implanted cup size of (50.57±2.74) mm, with no significant difference ( P>0.05). Regarding agreement with the actual implanted cup size, the preoperative template planning achieved exact matches in 35 hips (43.75%), one-size deviation in 41 hips (51.25%), and two-size deviations in 4 hips (5%); the radiographic FHD measurement achieved exact matches in 12 hips (15%), one-size deviation in 57 hips (71.25%), and two-size deviations in 11 hips (13.75%); and the intraoperative FHD measurement achieved exact matches in 26 hips (32.5%), one-size deviation in 52 hips (65%), and two-size deviations in 2 hips (2.5%). There were significant differences in agreement distributions between the three methods and the actual implanted cup sizes ( H=18.579, P<0.001). CONCLUSION The intraoperative FHD measurement, as a simple, cost-effective, and accurate method, effectively guides acetabular cup selection, reduces the risk of prosthesis wear, enhances postoperative joint stability.
Humans ; Arthroplasty, Replacement, Hip/instrumentation* ; Male ; Female ; Middle Aged ; Acetabulum/diagnostic imaging* ; Aged ; Hip Prosthesis ; Prosthesis Design ; Femur Head/surgery* ; Osteoarthritis, Hip/surgery* ; Radiography ; Femoral Neck Fractures/surgery* ; Femur Head Necrosis/surgery*

OBJECTIVE: To compare the effects of double-channel core decompression (CD) combined with medullary cavity irrigation with those of simple CD on progression of collapse and clinical outcomes in non-traumatic osteonecrosis of the femoral head (ONFH). METHODS: A retrospective analysis was conducted on the clinical data of 19 patients (30 hips) with non-traumatic ONFH who underwent double-channel CD combined with medullary cavity irrigation and admitted between January 2024 and October 2024 (CD+irrigation group). According to a 1: 2 ratio, 54 patients (60 hips) who underwent simple CD and were matched in terms of age, gender, and body mass index (BMI) were included as the control (CD group). There was no significant difference in baseline data such as age, gender, BMI, affected side, ONFH type, preoperative Association Research Circulation Osseous (ARCO) stage, bone marrow edema stage, visual analogue scale (VAS) score for pain, and Harris score between the two groups ( P>0.05). The postoperative discharge time and occurrence of complications were recorded for both groups. The VAS scores before operation and at discharge after operation were compared, and the differences between pre- and post-operation (change values) were calculated for intergroup comparison. The Harris scores before operation and at discharge and 3 months after operation were also compared. During follow-up, X-ray film, CT, and MRI were performed for reexamination. The ARCO stage and bone marrow edema stage were evaluated at 3 months after operation and compared with those before operation to determine whether there was radiological progression or relief. RESULTS: All incisions in both groups healed by first intention after operation, with no infection, femoral neck fracture, or other operation-related complications. All patients were followed up, and the follow-up time of the CD+irrigation group was (146.8±27.7) days, and that of the CD group was (164.3±48.2) days; there was no significant difference between the two groups ( t=1.840, P=0.069). There was no significant difference in the length of hospital stay between the two groups ( P>0.05). At discharge after operation, the VAS score of the CD+irrigation group was significantly lower than that of the CD group ( P<0.05), and the change value was significantly higher than that of the CD group ( P<0.05). The Harris scores at discharge and 3 months after operation in the CD+irrigation group were significantly higher than those in the CD group ( P<0.05). The Harris score gradually increased with time, and the differences between different time points were significant ( P<0.05). Radiological reexamination showed that there was no significant difference in the ARCO stage and the incidence of radiological progression between the two groups at 3 months after operation ( P>0.05); however, the bone marrow edema stage and the degree of bone marrow edema relief in the CD+irrigation group were better than those in the CD group, with significant differences ( P<0.05). CONCLUSION Double-channel CD combined with medullary cavity irrigation can significantly alleviate hip joint pain and improve joint function in patients with non-traumatic ONFH, reduce the degree of bone marrow edema in the femoral head, and delay the progression of ONFH.
Humans ; Femur Head Necrosis/therapy* ; Retrospective Studies ; Male ; Female ; Decompression, Surgical/methods* ; Therapeutic Irrigation/methods* ; Adult ; Treatment Outcome ; Middle Aged ; Femur Head/surgery*

OBJECTIVE: To assess the mid-term clinical efficacy of the direct anterior approach for window decompression and bone grafting surgery in the treatment of early to mid-stage osteonecrosis of the femoral head (ONFH). METHODS: A retrospective analysis was performed on 40 patients (40 hips) diagnosed with osteonecrosis of the femoral head (ONFH), classified as types L1 and L2 according to the China-Japan Friendship Hospital (CJFH) classification system, and at stagesⅡ, ⅢA, and ⅢB based on the Association Research Circulation Osseous (ARCO) staging system. All patients underwent head-neck junction fenestration decompression and bone grafting via the direct anterior approach between January 2015 and May 2022, with complete follow-up data available for a minimum of three years. The ages of the patients ranged from 35 to 69 years old, with a mean of (49.13±6.14 ) years old;their body mass index (BMI) ranged from 20.02 to 27.94 kg·m^-2, with a mean of (23.65±1.69) kg·m^-1;the duration of the disease ranged from 13 to 36 months, with a mean of (24.55±4.14) months. Preoperative and 3-year postoperative X-ray parameters were collected, including the anterior preserved angle(APA), lateral preserved angle (LPA), and combined preserved angle (CPA). Additionally, hip joint disability and osteoarthritis outcome scores (HOOS) and Harris hip scores (HHS) were recorded. RESULTS: Forty patients were followed up for a period ranging from 36 to 59 months, with a mean duration of (47.18±6.18) months. At 3 years postoperative, none of the patients underwent hip replacement surgery. The APA (73.15±19.35)°, LPA (75.35 ±21.48)°, and CPA (136.25±26.78)° at the 3-year postoperative significantly improved compared to preoperative measurements (61.93±20.54)°, (59.46±22.67)°, and (116.58±32.47)°, with statistical significance (P<0.05). The HOOS (20.37±1.39) and HHS (89.74±3.28) scores at the 3-year postoperative were significantly improved from preoperative scores (12.36±1.58) and (50.27±6.15), respectively, with statistical significance (P<0.05). CONCLUSION The direct anterior approach for window decompression and bone grafting surgery can relieve joint pain, improve joint function, and enhance X-ray preserved angles, effectively preventing femoral head collapse, making it an effective surgical method for treating ONFH classified as L1, L2 according to CJFH and stagesⅡ, ⅢA, ⅢB according to ARCO.
Humans ; Middle Aged ; Male ; Female ; Adult ; Decompression, Surgical/methods* ; Bone Transplantation ; Femur Head Necrosis/surgery* ; Follow-Up Studies ; Aged ; Retrospective Studies

OBJECTIVE: To analyze the femoral head collapse and the operation of osteonecrosis of the femoral head (ONFH) in different Japanese Investigation Commitee (JIC) types, in order to summarize the prognostic rules of each type of ONFH, and explore the clinical significance of CT lateral subtypes based on reconstruction of necrotic area of C1 type and verify their clinical effect. METHODS: A total of 119 patients (155 hips) with ONFH between May 2004 and December 2016 were enrolled in the study. The total hips consisted of 34 hips in type A, 33 in type B, 57 in type C1, and 31 in type C2, respectively. There was no significant difference in age, gender, affected side, or type of ONFH of the patients with differenct JIC types ( P>0.05). The 1-, 2-, and 5-year femoral head collapse and operation of different JIC types were analyzed, as well as the survival rate (with femoral head collapse as the end point) of hip joint between different JIC types, hormonal/non-hormonal ONFH, asymptomatic and symptomatic (pain duration >6 months or ≤6 months), and combined preserved angle (CPA) ≥118.725° and CPA<118.725°. JIC types with significant differences in subgroup surgery and collapse and with research value were selected. According to the location of the necrotic area on the surface of the femoral head, the JIC classification was divided into 5 subtypes in the lateral CT reconstruction, and the contour line of the necrotic area was extracted and matched to the standard femoral head model, and the necrosis of the five subtypes was presented by thermography. The 1-, 2-, and 5-year outcomes of femoral head collapse and operation in different lateral subtypes were analyzed, and the survival rates (with collapse of the femoral head as the end point) between CPA≥118.725° and CPA<118.725° hip in patients with this subtype were compared, as well as the survival rates of different lateral subtypes (with collapse and surgery as the end points, respectively). RESULTS: The femoral head collapse rate and operation rate in the 1-, 2-, and 5-year were significantly higher in patients with JIC C2 type than in patients with other hip types ( P<0.05), while in patients with JIC C1 type than in patients with JIC types A and B ( P<0.05). The survival rate of patients with different JIC types was significantly different ( P<0.05), and the survival rate of patients with JIC types A, B, C1, and C2 decreased gradually. The survival rate of asymptomatic hip was significantly higher than that of symptomatic hip, and the survival rate of CPA≥118.725° was significantly higher than that of CPA<118.725° ( P<0.05). The lateral CT reconstruction of type C1 hip necrosis area was selected for further classification, including type 1 in 12 hips, type 2 in 20 hips, type 3 in 9 hips, type 4 in 9 hips, and type 5 in 7 hips. There were significant differences in the femoral head collapse rate and the operation rate among the subtypes after 5 years of follow-up ( P<0.05). The collapse rate and operation rate of types 4 and 5 were 0; the collapse rate and operation rate of type 3 were the highest; the collapse rate of type 2 was high, but the operation rate was lower than that of type 3; the collapse rate of type 1 was high, but the operation rate was 0. In JIC type C1 patients, the survival rate of the hip joint with CPA≥118.725° was significantly higher than that with CPA<118.725° ( P<0.05). In the follow-up with femoral head collapse as the end point, the survival rates of types 4 and 5 were all 100%, while the survival rates of types 1, 2, and 3 were all 0, and the difference was significant ( P<0.05). The survival rate of types 1, 4, and 5 was 100%, of type 3 was 0, and of type 2 was 60%, showing significant difference ( P<0.05). CONCLUSION JIC types A and B can be treated by non-surgical treatment, while type C2 can be treated by surgical treatment with hip preservation. Type C1 was classified into 5 subtypes by CT lateral classification, type 3 has the highest risk of femoral head collapse, types 4 and 5 have low risk of femoral head collapse and operation, type 1 has high femoral head collapse rate but low risk of operation; type 2 has high collapse rate, but the operation rate is close to the average of JIC type C1, which still needs to be further studied.
Humans ; Femur Head/surgery* ; Femur Head Necrosis/surgery* ; Retrospective Studies ; Hip Joint ; Tomography, X-Ray Computed

OBJECTIVE: The biomechanical characteristics of three internal fixation modes for femoral subtrochanteric spiral fracture in osteoporotic patients were compared and analyzed by finite element technology, so as to provide the basis for the optimization of fixation methods for femoral subtrochanteric spiral fracture. METHODS: Ten female patients with osteoporosis and femoral subtrochanteric spiral fractures caused by trauma, aged 65-75 years old, with a height of 160-170 cm and a body weight mass of 60-70 kg, were selected as the study subjects. The femur was scanned by spiral CT and a three-dimensional model of the femur was established by digital technology. The computer aided design models of proximal intramedullary nail (PFN), proximal femoral locking plate (PFLP), and the combination of the two (PFLP+PFN) were constructed under the condition of subtrochanteric fracture. Then the same load of 500 N was applied to the femoral head, and the stress distribution of the internal fixators, the stress distribution of the femur, and the displacement of femur after fracture fixation were compared and analyzed under the three finite element internal fixation modes, so as to evaluate the fixation effect. RESULTS: In the PFLP fixation mode, the stress of the plate was mainly concentrated in the main screw channel, the stresses of the different part of the plate were not equal, and gradually decreased from the head to the tail. In the PFN fixation mode, the stress was concentrated in the upper part of the lateral middle segment. In the PFLP+PFN fixation mode, the maximum stress appeared between the first and the second screws in the lower segment, and the maximum stress appeared in the lateral part of the middle segment of the PFN. The maximum stress of PFLP+PFN fixation mode was significantly higher than that of PFLP fixation mode, but significantly lower than that of PFN fixation mode ( P<0.05). In PFLP and PFN fixation modes, the maximum stress of femur appeared in the medial and lateral cortical bone of the middle femur and the lower side of the lowest screw. In PFLP+PFN fixation mode, the stress of femur concentrated in the medial and lateral of the middle femur. There was no significant difference in the maximum stress of femur among the three finite element fixation modes ( P>0.05). The maximum displacement occurred at the femoral head after three finite element fixation modes were used to fix subtrochanteric femoral fractures. The maximum displacement of femur in PFLP fixation mode was the largest, followed by PFN, and PFLP+PFN was the minimum, with significant differences ( P<0.05). CONCLUSION Under static loading conditions, the PFLP+PFN fixation mode produces the smallest maximum displacement when compared with the single PFN and PFLP fixation modes, but its maximum plate stress is greater than the single PFN and PFLP fixation mode, suggesting that the combination mode has higher stability, but the plate load is greater, and the possibility of fixation failure is higher.
Humans ; Female ; Aged ; Finite Element Analysis ; Biomechanical Phenomena ; Fracture Fixation, Internal/methods* ; Hip Fractures/surgery* ; Bone Plates ; Femur Head ; Femoral Fractures/surgery*

OBJECTIVE: To investigate the value of CT-based radiomics and clinical data in predicting the efficacy of non-vascularized bone grafting (NVBG) in hip preservation, and to construct a visual, quantifiable, and effective method for decision-making of hip preservation. METHODS: Between June 2009 and June 2019, 153 patients (182 hips) with osteonecrosis of the femoral head (ONFH) who underwent NVBG for hip preservation were included, and the training and testing sets were divided in a 7∶3 ratio to define hip preservation success or failure according to the 3-year postoperative follow-up. The radiomic features of the region of interest in the CT images were extracted, and the radiomics-scores were calculated by the linear weighting and coefficients of the radiomic features after dimensionality reduction. The clinical predictors were screened using univariate and multivariate Cox regression analysis. The radiomics model, clinical model, and clinical-radiomics (C-R) model were constructed respectively. Their predictive performance for the efficacy of hip preservation was compared in the training and testing sets, with evaluation indexes including area under the curve, C-Index, sensitivity, specificity, and calibration curve, etc. The best model was visualised using nomogram, and its clinical utility was assessed by decision curves. RESULTS: At the 3-year postoperative follow-up, the cumulative survival rate of hip preservation was 70.33%. Continued exposure to risk factors postoperative and Japanese Investigation Committee (JIC) staging were clinical predictors of the efficacy of hip preservation, and 13 radiomic features derived from least absolute shrinkage and selection operator downscaling were used to calculate Rad-scores. The C-R model outperformed both the clinical and radiomics models in predicting the efficacy of hip preservation 1, 2, 3 years postoperative in both the training and testing sets ( P<0.05), with good agreement between the predicted and observed values. A nomogram constructed based on the C-R model showed that patients with lower Rad-scores, no further postoperative exposure to risk factors, and B or C1 types of JIC staging had a higher probability of femoral survival at 1, 2, 3 years postoperatively. The decision curve analysis showed that the C-R model had a higher total net benefit than both the clinical and radiomics models with a single predictor, and it could bring more net benefit to patients within a larger probability threshold. CONCLUSION The prediction model and nomogram constructed by CT-based radiomics combined with clinical data is a visual, quantifiable, and effective method for decision-making of hip preservation, which can predict the efficacy of NVBG before surgery and has a high value of clinical application.
Humans ; Bone Transplantation ; Femur Head/surgery* ; Femur ; Osteonecrosis ; Tomography, X-Ray Computed ; Retrospective Studies

For the treatment of an intertrochanteric fracture combined with femoral head necrosis in middle-age patients, it has been controversial whether to perform fracture reduction and fixation first then total hip replacement, or direct total hip replacement. We present a rare case of 53-year-old male patient suffered from bilateral intertrochanteric fracture caused by a road traffic injury. The patient had a history of femoral head necrosis for eight years, and the Harris score was 30. We performed total hip replacement with prolonged biologic shank prostheses for primary repair. One year after the surgery, nearly full range of motion was achieved without instability (active flexion angle of 110°, extension angle of 20°, adduction angle of 40°, abduction angle of 40°, internal rotation angle of 25°, and external rotation angle of 40°). The Harris score was 85. For the middle-aged patient with unstable intertrochanteric fractures and osteonecrosis of the femoral head, we can choose primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement.
Male ; Middle Aged ; Humans ; Arthroplasty, Replacement, Hip/methods* ; Femur Head/surgery* ; Femur Head Necrosis/surgery* ; Fracture Fixation, Internal/methods* ; Hip Fractures/surgery* ; Biological Products ; Treatment Outcome ; Retrospective Studies

OBJECTIVE: To explore effectiveness of positive support reduction and internal fixation in the treatment of femoral neck fractures. METHODS: A clinical data of 74 patients with femoral neck fractures treated with hollow screw internal fixation between September 2017 and September 2021 was retrospectively analyzed. Based on the quality of fracture reduction, they were divided into positive support reduction group (group A, n=25), negative support reduction group (group B, n=21), and anatomical reduction group (group C, n=28). There was no significant difference in baseline data such as gender, age, cause of injury, disease duration, fracture side, Garden classification, and fracture line position classification between groups (P>0.05). The occurrence of complications such as early fixation failure, femoral neck shortening, non-union of fractures, and femoral head necrosis in three groups, as well as the Harris score of the hip joint were recorded and compared. RESULTS: All patients had primary healing of incisions after operation and were followed up more than 12 months. The follow-up time for groups A, B, and C was (21.1±5.7), (22.6±4.3), and (21.9±4.1) months, respectively; there was no significant difference between groups (P>0.05). There was no significant difference in the incidences of non-union of fractures, early internal fixation failure, and the femoral head necrosis between groups (P>0.05). The incidence and length of femoral neck shortening, and the hip Harris score at last follow-up in groups A and C were all superior to those in the group B, with significant difference (P<0.05). There was no significant difference in the above indicators between groups A and C (P>0.05). CONCLUSION Positive support reduction can provide a good biomechanical environment for the healing of femoral neck fractures, thereby achieving a higher fracture healing rate, reducing the occurrence of femoral neck shortening, minimizing the function of hip joint, and achieving effectiveness similar to anatomical reduction.
Humans ; Femur Head Necrosis ; Retrospective Studies ; Femoral Neck Fractures/surgery* ; Femur Neck ; Plastic Surgery Procedures

OBJECTIVE: To explore the design points of a three-dimensional (3D) printed customized cementless intercalary endoprosthesis with an intra-neck curved stem and to evaluate the key points and mid-term effectiveness of its application in the reconstruction of ultrashort bone segments in the proximal femur. METHODS: Between October 2015 and January 2021, 17 patients underwent reconstruction with a 3D printed-customized cementless intercalary endoprosthesis with an intra-neck curved stem. There were 11 males and 6 females, the age ranged from 10 to 76 years, with an average of 30.1 years. There were 9 cases of osteosarcoma, 4 cases of Ewing sarcoma, 2 cases of chondrosarcoma, 1 case of liposarcoma, and 1 case of myofibroblastoma. The disease duration was 5-14 months, with an average of 9.5 months. Enneking staging included 16 cases of stage ⅡB and 1 case of stage ⅢB. The distances from the center of the femoral head to the body midline and the acetabular apex were measured preoperatively on X-ray images. Additionally, the distances from the tip of the intra-neck curved stem to the body midline and the acetabular apex were measured at immediate postoperatively and last follow-up. The neck-shaft angle was also measured preoperatively, at immediate postoperatively, and at last follow-up. The status of osseointegration at the bone-prosthesis interface and bone growth into the prosthesis surface were assessed by X-ray films, CT, and Tomosynthesis-Shimadzu metal artefact reduction technology (T-SMART). The survival status of the patients, presence of local recurrence or distant metastasis, and occurrence of postoperative complications were assessed. The recovery of lower limb function was evaluated pre- and post-operatively using the Musculoskeletal Tumor Society (MSTS) scoring system, and pain relief was evaluated using the visual analogue scale (VAS) scores. RESULTS: The patient's femoral resection length was (163.1±57.5) mm, the remaining proximal femoral length was (69.6±9.3) mm, and the percentage of femoral resection length/total femoral length was 38.7%±14.6%. All 17 patients were followed up 25-86 months with an average of 58.1 months. During the follow-up, 1 patient died of lung metastasis at 46 months postoperatively, and the remaining 16 patients survived tumor-free. There was no complication such as periprosthetic infection, delayed incision healing, aseptic loosening, prosthesis fracture, or periprosthetic fracture. No evidence of micromotion or wear around the implanted stem of the prosthesis was detected in X-ray and T-SMART evaluations. There was no significant radiolucent lines, and radiographic evidence of bone ingrowth into the bone-prosthesis interface was observed in all stems. There was no significant difference in the distance from the tip of the curved stem to the body midline and the apex of the acetabulum at immediate postoperatively and last follow-up compared with the distance from the center of the femoral head to the body midline and the apex of the acetabulum before operation, respectively (P>0.05), and there was no significant difference in the above indexes between immediate postoperatively and last follow-up (P>0.05). The differences in the neck-shaft angle at various time points before and after operation were also not significant (P>0.05). At last follow-up, the MSTS score was 26.1±1.2 and the VAS score was 0.1±0.5, which were significantly improved when compared with those before operation [19.4±2.1 and 5.7±1.0, respectively] (t=14.735, P<0.001; t=21.301, P<0.001). At last follow-up, none of the patients walked with the aid of crutches or other walkers. CONCLUSION The 3D printed customized cementless intercalary endoprosthesis with an intra-neck curved stem is an effective method for reconstructing ultrashort bone segments in the proximal femur following malignant tumor resection. The operation is reliable, the postoperative lower limb function is satisfactory, and the incidence of complications is low.
Female ; Male ; Humans ; Child ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Femur/surgery* ; Lower Extremity ; Bone-Implant Interface ; Femur Head ; Artificial Limbs

OBJECTIVE: To establish finite element models of different preserved angles of osteonecrosis of the femoral head (ONFH) for the biomechanical analysis, and to provide mechanical evidence for predicting the risk of ONFH collapse with anterior preserved angle (APA) and lateral preserved angle (LPA). METHODS: A healthy adult was selected as the study object, and the CT data of the left femoral head was acquired and imported into Mimics 21.0 software to reconstruct a complete proximal femur model and construct 3 models of necrotic area with equal volume and different morphology, all models were imported into Solidworks 2022 software to construct 21 finite element models of ONFH with LPA of 45°, 50°, 55°, 60°, 65°, 70°, and 75° when APA was 45°, respectively, and 21 finite element models of ONFH with APA of 45°, 50°, 55°, 60°, 65°, 70°, 75° when LPA was 45°, respectively. According to the physiological load condition of the femoral head, the distal femur was completely fixed, and a force with an angle of 25°, downward direction, and a magnitude of 3.5 times the subject's body mass was applied to the weight-bearing area of the femoral head surface. The maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head were calculated and observed by Abaqus 2021 software. RESULTS: The finite element models of ONFH were basically consistent with biomechanics of ONFH. Under the same loading condition, there was stress concentration around the necrotic area in the 42 ONFH models with different preserved angles composed of 3 necrotic areas with equal volume and different morphology. When APA was 60°, the maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head of the ONFH models with LPA<60° were significantly higher than those of the models with LPA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with LPA≥60° ( P>0.05). When LPA was 60°, each index of the ONFH models with APA<60° were significantly higher than those of the models with APA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with APA≥60° ( P>0.05). CONCLUSION From the perspective of biomechanics, when a preserved angle of ONFH is less than its critical value, the stress concentration phenomenon in the femoral head is more pronounced, suggesting that the necrotic femoral head may have a higher risk of collapse in this state.
Adult ; Humans ; Femur Head/surgery* ; Finite Element Analysis ; Stress, Mechanical ; Femur/diagnostic imaging* ; Femur Head Necrosis/surgery*