ObjectiveTo investigate the short- and mid-term effectiveness of revision hip arthroplasty by using impaction bone allograft and acetabular components in treatment of severe acetabular defects.MethodsA clinical data of 42 patients (44 hips) with severe acetabular defects between February 2011 and May 2018 were retrospectively analyzed. All patients underwent revision hip arthroplasty by using impaction bone allograft and acetabular components. Cemented cup (24 cases, 24 hips) and non-cemented cup (18 cases, 20 hips) were used in the revision surgery. There were 17 males and 25 females with an average age of 62.8 years (range, 22-84 years). The interval between the first total hip arthroplasty and revision was 2.5-12.0 years (mean, 8.3 years). The patients were accepted revision surgery for prosthesis aseptic loosening in 32 hips (31 cases) and the periprosthetic infection in 12 hips (11 cases). Twenty-nine hips (28 cases) were Paprosky type ⅢA and 15 hips (14 cases) were type ⅢB. The preoperative Harris score was 22.25±10.31 and the height of hip rotation center was (3.67±0.63) cm and the length difference of lower limbs was (3.41±0.64) cm.ResultsThe operation time was 130-245 minutes (mean, 186 minutes) and the intraoperative blood loss was 600-2 400 mL (mean, 840 mL). The postoperative drainage volume was 250-1 450 mL (mean, 556 mL). Superficial infection of the incision occurred in 1 case, and the incisions healed by first intention in the other patients. All patients were followed up 6-87 months, with an average of 48.6 months. At last follow-up, the Harris score was 85.85±9.31, which was significantly different from the preoperative score (t=18.563, P=0.000). Imaging examination revealed that the allogeneic bone gradually fused with the host bone, and no obvious bone resorption was observed. At last follow-up, the height of the hip rotation center was (1.01±0.21) cm, which was significantly different from the preoperative level (t=17.549, P=0.000); the length difference of lower limbs was (0.62±0.51) cm, which was significantly different from the preoperative level (t=14.211, P=0.000). The Harris score in the cemented group and non-cemented group increased significantly at last follow-up. The height of the hip rotation center decreased, and the hip rotation centers of both groups were within the Ranawat triangle zone. The length difference of the lower limbs also decreased, and the differences in all indexes were significant between pre- and post-operation (P<0.05). There was significant difference in the height of the hip rotation center between groups (t=2.095, P=0.042), but there was no significant difference in the Harris score and the length difference of lower limbs between groups (P>0.05).ConclusionFor severe acetabular defect (Paprosky type Ⅲ), the hip can be reconstructed with the impaction bone allograft and cemented or non-cemented components in revision hip arthroplsty. The short- and mid-term effectiveness are satisfactory.
ObjectiveTo explore the different imaging manifestations of osteonecrosis of the femoral head (ONFH) and their correlation with the occurrence of pain during the peri-collapse period.MethodsThe 372 patients (624 hips) with ONFH in the peri-collapse stage who were admitted between December 2016 and October 2019 and met the selection criteria were selected as the research objects. Among them, there were 270 males and 102 females, with an average age of 35.3 years (mean, 15-65 years). There were 120 cases of unilateral hip and 252 cases of bilateral hips. There were 39 cases (39 hips) of traumatic ONFH, 196 cases (346 hips) of hormonal ONFH, 102 cases (178 hips) of alcoholic ONFH, and 35 cases (61 hips) of idiopathic ONFH. Among them, there were 482 hips with pain symptoms and 142 hips without pain. The pain duration was less than 3 months in 212 hips, 3-6 months in 124 hips, 6-12 months in 117 hips, and more than 12 months in 29 hips. According to the Association Research Circulation Osseous (ARCO) staging, the ONFH was rated as stage Ⅱ in 325 hips and stage Ⅲ in 299 hips. The patients were grouped according to ONFH etiology and ARCO staging, and hip joint pain and X-ray film (crescent sign and cystic changes), CT (subchondral bone fractures and cystic changes), and MRI (bone marrow edema, joint effusion, and subchondral hypointensity zone) were compared. Spearman rank correlation was used to determine the correlation between ONFH pain duration and X-ray film, CT, and MRI imaging manifestations.ResultsThere were significant differences (P<0.05) between ONFH patients with different etiologies in crescent sign on X-ray film, subchondral bone fracture on CT, and joint effusion on MRI. And there were significant differences (P<0.05) between ONFH patients with different ARCO stages in hip pain duration and all imaging manifestations. Correlation analysis showed that the pain duration of ONFH patients was correlated with all imaging manifestations (P<0.05). The cystic change on CT was correlated with the subchondral hypointensity zone and joint effusion grade on MRI, and subchondral hypointensity zone and joint effusion grade on MRI were also correlated (P<0.05).ConclusionThe cystic changes, subchondral hypointensity zone, and joint effusion are closely related to the collapse of the femoral head and hip pain in patients with ONFH in the peri-collapse stage. The above-mentioned signals in stage Ⅱ ONFH indicate the instability of the femoral head, which is to predict the development of ONFH and the rational choice of hip-preserving treatment methods provides a basis.
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). ResultsThe 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.
ObjectiveTo explore the predictive effect of the femoral neck strength composite indexes on femoral head collapse in non-traumatic osteonecrosis of the femoral head (ONFH) compared with bone turnover marker.MethodsThe non-traumatic ONFH patients who were admitted and received non-surgical treatment between January 2010 and December 2016 as the research object. And 96 cases (139 hips) met the selection criteria and were included in the study. There were 54 males (79 hips) and 42 females (60 hips), with an average age of 40.2 years (range, 22-60 years). According to whether the femoral head collapsed during follow-up, the patients were divided into collapsed group and non-collapsed group. The femoral neck width, hip axis length, height, body weight, and bone mineral density of femoral neck were measured. The femoral neck strength composite indexes, including the compressive strength index (CSI), bending strength index (BSI), and impact strength index (ISI), were calculated. The bone turnover marker, including the total typeⅠcollagen amino terminal elongation peptide (t-P1NP), β-crosslaps (β-CTx), alkaline phosphatase (ALP), 25 hydroxyvitamin D [25(OH)D], and N-terminal osteocalcin (N-MID), were measured. The age, gender, height, body weight, body mass index (BMI), bone mineral density of femoral neck, etiology, Japanese Osteonecrosis Investigation Committee (JIC) classification, femoral neck strength composite indexes, and bone turnover marker were compared between the two groups, and the influencing factors of the occurrence of femoral head collapse were initially screened. Then the significant variables in the femoral neck strength composite indexes and bone turnover marker were used for logistic regression analysis to screen risk factors; and the receiver operating characteristic (ROC) curve was used to determine the significant variables’ impact on non-traumatic ONFH. ResultsAll patients were followed up 3.2 years on average (range, 2-4 years). During follow-up, 46 cases (64 hips) had femoral head collapse (collapsed group), and the remaining 50 cases (75 hips) did not experience femoral head collapse (non-collapsed group). Univariate analysis showed that the difference in JIC classification between the two groups was significant (Z=–7.090, P=0.000); however, the differences in age, gender, height, body weight, BMI, bone mineral density of femoral neck, and etiology were not significant (P>0.05). In the femoral neck strength composite indexes, the CSI, BSI, and ISI of the collapsed group were significantly lower than those of the non-collapsed group (P<0.05); in the bone turnover marker, the t-P1NP and β-CTx of the collapsed group were significantly lower than those of the non-collapsed group (P<0.05); there was no significant difference in N-MID, 25(OH)D or ALP between groups (P>0.05). Multivariate analysis showed that the CSI, ISI, and t-P1NP were risk factors for femoral collapse in patients with non-traumatic ONFH (P<0.05). ROC curve analysis showed that the cut-off points of CSI, BSI, ISI, t-P1NP, and β-CTx were 6.172, 2.435, 0.465, 57.193, and 0.503, respectively, and the area under the ROC curve (AUC) were 0.753, 0.642, 0.903, 0.626, and 0.599, respectively. ConclusionThe femoral neck strength composite indexes can predict the femoral head collapse in non-traumatic ONFH better than the bone turnover marker. ISI of 0.465 is a potential cut-off point below which future collapse of early non-traumatic ONFH can be predicted.
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. ResultsThe 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.
Objective To investigate the impact of the bone mass and volume of the low-density area under the tibial plateau on the lower limb force line by finite element analysis, offering mechanical evidence for preventing internal displacement of the lower limb force line in conjunction with knee varus in patients with knee osteoarthritis (KOA) and reducing bone mass under the tibial plateau. Methods A healthy adult was selected as the study subject, and X-ray film and CT imaging data were acquired. Mimics 21.0 software was utilized to reconstruct the complete knee joint model and three models representing low-density areas under the tibial plateau with equal volume but varying shapes. These models were then imported into Solidworks 2023 software for assembly and verification. Five KOA finite element models with 22%, 33%, 44%, 55%, and 66% bone mass reduction in the low-density area under tibial plateau and 5 KOA finite element models with 81%, 90%, 100%, 110%, and 121% times of the low-density area model with 66% bone mass loss were constructed, respectively. Under physiological loading conditions of the human lower limb, the distal ends of the tibia and fibula were fully immobilized. An axial compressive load of 1 860 N, following the lower limb force line, was applied to the primary load-bearing area on the femoral head surface. The maximum stress within the tibial plateau, as well as the maximum displacements of the tibial cortical bone and tibial subchondral bone, were calculated and analyzed using the finite element analysis software Abaqus 2022. Subsequently, predictions regarding the alteration of the lower limb force line were made based on the analysis results. Results The constructed KOA model accorded with the normal anatomical structure of lower limbs. Under the same boundary conditions and the same load, the maximum stress of the medial tibial plateau, the maximum displacement of the tibial cortical bone and the maximum displacement of the cancellous bone increased along with the gradual decrease of bone mass in the low-density area under the tibial plateau and the gradual increase in the volume of the low-density area under tibial plateau, with significant differences (P<0.05). ConclusionThe existence of a low-density area under tibial plateau suggests a heightened likelihood of knee varus and inward movement of the lower limb force line. Both the volume and reduction in bone mass of the low-density area serve as critical initiating factors. This information can provide valuable guidance to clinicians in proactively preventing knee varus and averting its occurrence.