Risk Factors for Periprosthetic Femoral Fractures After Cementless Total Hip Arthroplasty.

BACKGROUND: The present study aimed to identify the risk factors of periprosthetic femoral fracture (PFF) after cementless total hip arthroplasty and rank them based on importance. METHODS: The age, sex, body mass index (BMI), osteoporosis, canal flare index (CFI), canal bone ratio (CBR), canal calcar ratio (CCR), stem design, and stem canal fill ratio (P1, P2, P3, and P4) of the proximal femoral medullary cavity of 111 total hip arthroplasty patients who had PFF and 388 who did not have PFF were analyzed. Independent-samples student t-tests were used for continuous variables, and Chi-square tests were used for categorical variables. The importance rankings of influencing factors were assessed using a random forest algorithm. Dimensionally reduced variables were then incorporated into a binary logistic regression model to determine the PFF-related risk factors. RESULTS: The mean age, BMI, CBR, CCR, and incidence of osteoporosis were higher in cases of PFF (all P < .001), while the mean CFI, P1, P2, P3, and P4 were lower in cases of PFF (P < .001, P = .033, P = .008, P < .001, and P < .001, respectively). Additionally, the stem design was also statistically associated with PFF (P < .001). Multivariate logistic regression revealed that advanced age, higher BMI, osteoporosis, stem design, lower CFI, higher CBR, higher CCR, lower P1, lower P2, lower P3, and lower P4 were the risk factors of PFF (P < .001, P < .001, P < .001, P < .001, P < .001, P = .010, P < .001, P = .002, P < .001, P < .001, and P = .007, respectively). The ranked importance of the risk factors for PFF was P3, CFI, osteoporosis, CBR, age, P4, P1, stem design, CCR, BMI, and P2. CONCLUSIONS: Lower P3, lower CFI, osteoporosis, higher CBR, advanced age, lower P4, lower P1, stem design, higher CCR, higher BMI, and lower P2 increased the risk of PFF.

Stiffness and shape of the ACL graft affects tunnel enlargement and graft wear.

PURPOSE: Tunnel enlargement and graft rupture are common complications associated with ACL reconstruction (ACLR). This study aims to explore how variations in graft stiffness and shape affect the strain energy density (SED) around bone tunnel entrances and stress on the graft and subsequently influencing the level of tunnel enlargement and graft wear. METHODS: Finite element ACLR models were developed using different graft stiffnesses (323 N/mm, 545 N/mm and 776 N/mm) and shapes (circular and elliptical). The models were subjected to a combined loading of 103 N anterior tibial load, 7.5 Nm internal tibial moment, and 6.9 Nm valgus tibial moment at joint flexion of 30°. SED at tunnel entrances and stresses on the graft was recorded and compared among the different models. RESULTS: Increasing the graft stiffness resulted in greater stress on the graft (17.2, 24.4 and 31.7 MPa for graft stiffnesses of 323 N/mm, 545 N/mm and 776 N/mm), but had little effect on the SED reduction around the tunnel entrances. Changing the cross section of the graft from circular to elliptical caused an additional reduction in SED (56.8 vs 2.8 kJ/m3) at the posterior zone of the femoral tunnel entrance and increased the stress on the graft (31.7 MPa vs 38.9 MPa). CONCLUSIONS: This study recommends using ACL grafts with lower stiffness and a circular cross section to reduce tunnel enlargement and graft wear following ACLR.

Impact of scapular notching on glenoid fixation in reverse total shoulder arthroplasty: an in vitro and finite element study.

BACKGROUND: The high incidence of scapular notching in reverse total shoulder arthroplasty (RTSA) has spurred several methods to minimize bone loss. However, up to 93% of RTSAs accompanying scapular notching have been reported to maintain good implant stability for over 10 years. This study was conducted to investigate the relationship between scapular notching and glenoid fixation in RTSA. METHODS: Cadaveric testing was performed to measure the notch-induced variations in strain on the scapular surface and micromotion at the bone-prosthesis interface during arm abductions of 30°, 60°, and 90°. Finite element analysis was used to further study the bone and screw stresses as well as the bone-prosthesis micromotion in cases with a grade 4 notch during complicated arm motions. RESULTS: The notch resulted in an apparent increase in inferior screw stress in the root of the screw cap and at the notch-screw conjunction. However, the maximum stress (172 MPa) along the screw after notching is still much less than the fatigue strength of the titanium screw (600 MPa) under cyclic loading. The bone-prosthesis micromotion results did not present significant notch-induced variations. CONCLUSIONS: Scapular notching will lead to few impacts on the stability of an RTSA on the glenoid side. This finding may explain the long-term longevity of RTSA in cases of severe scapular notching. The relationship between scapular notching and weak regions along the inferior screw may explain why fractures of the inferior screw are sometimes reported in patients with RTSA clinically.

Motion type and knee articular conformity influenced mid-flexion stability of a single radius knee prosthesis.

PURPOSE: Single radius knee implants were introduced to reduce the level of paradoxical anterior femoral translation (AFT) during mid-flexion after total knee arthroplasty. Findings from clinical and experiment studies are inconsistent, which may be due to the different loading conditions and articular conformities of the knee implants studied. The aim of this study is to analyze how variations in these two factors affect the mid-flexion stability of a single radius knee prosthesis. METHODS: Six daily activities (walking, stair ascent, stair descent, sit-to-stand, pivot turn and crossover turn), and three articular conformity ratios (low, moderate and high) were considered. The resulting AFTs from the 18 finite element models were analyzed. RESULTS: For low conformity knees, the worst case activity (the greatest AFT) was sit-to-stand with an AFT of 6.2 mm, while for the moderate conformity the worst case was crossover turn and pivot turn. For high conformity, all activities produced a relatively small AFT ranging from 0 mm to 1.8 mm, which more closely resembles natural knee motion. In addition, no AFT was recorded during stair ascent for all three conformities (low, moderate, high). CONCLUSIONS: This study demonstrated that the amount of AFT is highly dependent on the activity being undertaken and the articular conformity of the knee prosthesis, and the worst case activity depends on the knee conformity. The clinical relevance of this study is that it offers valuable information towards the design of improved knee prostheses and selection of knee implants for clinical use. LEVEL OF EVIDENCE: II.

Biocompatibility and Osteogenic Capacity of Mg-Zn-Ca Bulk Metallic Glass for Rabbit Tendon-Bone Interference Fixation.

Mg-based alloys have great potential for development into fixation implants because of their highly biocompatible and biodegradable metallic properties. In this study, we sought to determine the biocompatibility of Mg60Zn35Ca5 bulk metallic glass composite (BMGC) with fabricated implants in a rabbit tendon-bone interference fixation model. We investigated the cellular cytotoxicity of Mg60Zn35Ca5 BMGC toward rabbit osteoblasts and compared it with conventional titanium alloy (Ti6Al4V) and polylactic acid (PLA). The results show that Mg60Zn35Ca5 BMGC may be classed as slightly toxic on the basis of the standard ISO 10993-5. We further characterized the osteogenic effect of the Mg60Zn35Ca5 BMGC extraction medium on rabbit osteoblasts by quantifying extracellular calcium and mineral deposition, as well as cellular alkaline phosphatase activity. The results of these tests were found to be promising. The chemotactic effect of the Mg60Zn35Ca5 BMGC extraction medium on rabbit osteoblasts was demonstrated through a transwell migration assay. For the in vivo section of this study, a rabbit tendon-bone interference fixation model was established to determine the biocompatibility and osteogenic potential of Mg60Zn35Ca5 BMGC in a created bony tunnel for a period of up to 24 weeks. The results show that Mg60Zn35Ca5 BMGC induced considerable new bone formation at the implant site in comparison with conventional titanium alloy after 24 weeks of implantation. In conclusion, this study revealed that Mg60Zn35Ca5 BMGC demonstrated adequate biocompatibility and exhibited significant osteogenic potential both in vitro and in vivo. These advantages may be clinically beneficial to the development of Mg60Zn35Ca5 BMGC implants for future applications.

Rotational Shortening of Collateral Ligament in TKR With Severe Deformity.

Instability of the knee joint after total knee replacement (TKR) is one of the most important reasons for revision TKR. Inadequate release or tightening of the collateral ligaments in the knee joint may cause instability and early failure. This study presents a case series study of a new technique for ligament balancing wherein the collateral ligament is detached from its origin and rotated (twisted) around its longitudinal axis to tighten the ligament before the origin is reattached to its original position. The surgical technique for collateral ligament tightening during TKR was performed on 6 patients with a deformed knee caused by osteoarthritis and rheumatoid arthritis. The range of motion, knee society score, and laxity of the patients' knee joint, after 7 months to 13 years of follow-up, were evaluated. The technique was successful, achieving good range of motion and satisfactory stability of the joint. Further evaluation in a larger number of cases and a comparative analysis with different techniques would further support the usefulness of this rotational ligamentoplasty technique.

Effect of different inner core diameters on structural strength of cannulated pedicle screws under various lumbar spine movements.

BACKGROUND: Currently, cannulated pedicle screws have been widely used in minimal invasive or navigation techniques. However, the stress distribution and the strength of different core diameters of cannulated screw are not clear. This study aimed to investigate the mechanical strength of cannulated screws with different inner core diameter under various lumbar spine movements using finite element analysis. RESULTS: The results showed that the von-Mises stress of a cannulated screw was larger than that of a solid screw in all loading conditions, especially above 2 mm in cannulated core diameter. In lateral bending, extension, and flexion, the maximum von-Mises stress was found approximate to the proximal thread for all types of screws. In rotation condition, the maximum von-Mises stress was located at the middle of the screw. Additionally, the difference in stiffness of instrumented levels was not significant among four screws under the same loading condition. CONCLUSION: Cannulated screws could provide enough stability for the vertebral body fusion comparing to solid screws. The diameter of cannulated core is suggested not to exceed 2.0 mm.

A Comparison Between Chinese and Caucasian 3-Dimensional Bony Morphometry in Presimulated and Postsimulated Osteotomy for Total Knee Arthroplasty.

BACKGROUND: The bone morphologies of intact knees were measured and compared between Chinese and Caucasian populations. However, to assess if distinct designs of implants are necessary for the Chinese population owing to different morphologies and sizes, the knee measurements after osteotomy performed in total knee arthroplasty were evaluated. METHODS: Thirty-seven Caucasian and 50 Chinese patients' knees were examined using computed tomography scans. Mimics were applied to reconstruct 3-dimensional bone models. Dimensions of the 3-dimensional knee models and simulated bone resections during total knee arthroplasty were measured using Geomagic Studio and Pro/ENGINEER. The morphologic measurements of the native and resected femur and tibia included the anteroposterior (AP) depth, mediolateral (ML) width, notch width, knee physical valgus angle, tibial slope angle, and the ML-to-AP ratio of the femur, tibia, and resected femur. Statistical analysis was performed using the independent samples t test and the Pearson correlation coefficient in SPSS for Windows. Values of P < .05 were considered significant. RESULTS: No measurements were significantly different between the Chinese and Caucasian knees. However, the Chinese female showed significant differences compared with the Chinese male on distal femoral measurements both presimulated and postsimulated osteotomy such as a smaller mean ML-to-AP ratio in presimulated (1.3 ± 0.1) and postsimulated (1.3 ± 0.1) osteotomy. CONCLUSION: The necessity of designing a full set of total knee components specifically for the Chinese population is still undetermined. However, we suggest designing femoral components specific for the Chinese females because of different postosteotomy distal femoral ML-to-AP ratio between the Chinese males and the Chinese females.

Change in collateral ligament length and tibiofemoral movement following joint line variation in TKA.

PURPOSE: The primary intent of total knee arthroplasty is the restoration of normal knee kinematics, with ligamentous constraint being a key influential factor. Displacement of the joint line may lead to alterations in ligament attachment sites relative to knee flexion axis and variance of ligamentous constraints on tibiofemoral movement. This study aimed to investigate collaterals strains and tibiofemoral kinematics with different joint line levels. METHODS: A previously validated knee model was employed to analyse the change in length of the collateral ligaments and tibiofemoral motion during knee flexion. The models shifted the joint line by 3 and 5 mm both proximally and distally from the anatomical level. The data were captured from full extension to flexion 135°. RESULTS: The elevated joint line revealed a relative increase in distance between ligament attachments for both collateral ligaments in comparison with the anatomical model. Also, tibiofemoral movement decreased with an elevation in the joint line. Conversely, lowering the joint line led to a significant decrease in distance between ligament attachments, but greater tibiofemoral motion. CONCLUSION: Elevation of the joint line would strengthen the capacity of collateral ligaments for knee motion constraint, whereas a distally shifted joint line might have the advantage of improving tibiofemoral movement by slackening the collaterals. It implies that surgeons can appropriately change the joint line position in accordance with patient's requirement or collateral tensions. A lowered joint line level may improve knee kinematics, whereas joint line elevation could be useful to maintain knee stability. LEVEL OF EVIDENCE: V.

Is the posterior cruciate ligament necessary for medial pivot knee prostheses with regard to postoperative kinematics?

PURPOSE: Excellent clinical and kinematical performance is commonly reported after medial pivot knee arthroplasty. However, there is conflicting evidence as to whether the posterior cruciate ligament should be retained. This study simulated how the posterior cruciate ligament, post-cam mechanism and medial tibial insert morphology may affect postoperative kinematics. METHODS: After the computational intact knee model was validated according to the motion of a normal knee, four TKA models were built based on a medial pivot prosthesis; PS type, modified PS type, CR type with PCL retained and CR type with PCL sacrificed. Anteroposterior translation and axial rotation of femoral condyles on the tibia during 0°-135° knee flexion were analyzed. RESULTS: There was no significant difference in kinematics between the intact knee model and reported data for a normal knee. In all TKA models, normal motion was almost fully restored, except for the CR type with PCL sacrificed. Sacrificing the PCL produced paradoxical anterior femoral translation and tibial external rotation during full flexion. CONCLUSION: Either the posterior cruciate ligament or post-cam mechanism is necessary for medial pivot prostheses to regain normal kinematics after total knee arthroplasty. The morphology of medial tibial insert was also shown to produce a small but noticeable effect on knee kinematics. LEVEL OF EVIDENCE: V.

Patellofemoral kinematics during deep knee flexion after total knee replacement: a computational simulation.

PURPOSE: Actions requiring deep knee flexion, such as kneeling and squatting, are challenging to perform after total knee replacement (TKR), though many manufactures emphasize that their knee prostheses could safely achieve high flexion. Little is known about the patellofemoral kinematics during deep flexion. This study aimed to track the movement of the patella during kneeling and squatting through dynamic computational simulation. METHODS: A validated knee model was used to analyse the patellar kinematics after TKR, including shifting, tilting and rotation. The data were captured from full extension to 135° of knee flexion. For kneeling, an anterior force of 500 N was applied perpendicularly on the tibial tubercle as the knee flexed from 90° to 135°. For squatting, a ground reaction force was applied through the tibia from full extension to 135° of flexion. RESULTS: This study found that patellar shifting and rotation in kneeling were similar to those while squatting. However, during kneeling, the patella had a greater medial tilt and showed signs of abrupt patellar tilt owning to an external force being concentrated on the tibial tubercle. CONCLUSIONS: In terms of squatting and kneeling movements, the latter is a more strenuous action for the patellofemoral joint after TKR due to the high forces acting on the tibial tubercle. It is suggested that overweight patients or those requiring high flexion should try to avoid kneeling to reduce the risk of the polyethylene wear. Further modification of trochlear geometry may be required to accommodate abrupt changes in patellar tilting. LEVEL OF EVIDENCE: II.

A mutation of the Col2a1 gene (G1170S) alters the transgenic murine phenotype and cartilage matrix homeostasis.

BACKGROUND/PURPOSE: Genomic studies have revealed that there is a significant association between a point mutation of the human Col2A1 gene (G1170S) and several hip disorders. The purpose of the study was to explore the phenotype and altered cartilage matrix homeostasis of transgenic mice carrying this mutated Col2a1 gene. METHODS: Wild-type and transgenic mice were used as the control and study groups, respectively. Body weight measurement, radiographic analysis, and histological analysis of the mice were carried out to describe differences between the wild-type and transgenic mice at different ages. Cartilage metabolism studies were also carried out, including an MTT assay of cellular proliferation and nitric oxide and glycosaminoglycan assays. Allelic expression levels of the mutant A allele and the normal G allele were established by TaqMan assay. Cytokine and protease gene expression were measured. RESULTS: Transgenic mice had a lower mean body weight, a deformed skeletal structure, and abnormal cartilage histomorphology. Chondrocyte proliferation was significantly compromised and this was linked to significantly higher NO secretion and less soluble glycosaminoglycan formation. TNF-α and IL-1ß gene expression was significantly upregulated, while MMP-13 gene expression was significantly downregulated. CONCLUSION: The mutant G1170S Col2a1 gene in mice clearly alters the transgenic murine phenotype and cartilage matrix homeostasis.

Extracorporeal shockwave therapy improves short-term functional outcomes of shoulder adhesive capsulitis.

BACKGROUND: The treatment of adhesive capsulitis is a dilemma for orthopaedic rehabilitation specialists. In this study, we assessed whether extracorporeal shockwave therapy (ESWT) improves the functional outcome of primary shoulder adhesive capsulitis. METHODS: In this prospective, randomized, controlled, single-blind clinical trial, we enrolled 40 patients with primary adhesive capsulitis to assess whether ESWT can improve the functional outcome of primary adhesive capsulitis better than oral steroid therapy. Patients were allocated to the oral steroid group or ESWT group with randomization. Functional outcome evaluations were performed using the Constant Shoulder Score (CSS) and Oxford Shoulder Score. RESULTS: Both groups showed significant improvement in the Oxford Shoulder Score evaluation throughout the study period. In the ESWT group, the total CSS and range of motion (ROM) parameter of the CSS in the ESWT group showed significant improvement from the fourth week that was better than that in the steroid group; the activities­of­daily living (ADL) parameter of the CSS achieved significance and was better than that in the steroid group at the sixth week. For the steroid group, pain was significantly reduced from baseline to the fourth week of the study; ADL and ROM improved at the fourth to 12th week. For the ESWT group, ADL and ROM improvements were significant from baseline to the sixth week. CONCLUSION: Our results showed that ESWT can be an alternative treatment, at least in the short-term, for primary adhesive capsulitis of the shoulder. In addition, all of the side effects of ESWT were transient and tolerable.

Biomechanical considerations in the design of high-flexion total knee replacements.

Typically, joint arthroplasty is performed to relieve pain and improve functionality in a diseased or damaged joint. Total knee arthroplasty (TKA) involves replacing the entire knee joint, both femoral and tibial surfaces, with anatomically shaped artificial components in the hope of regaining normal joint function and permitting a full range of knee flexion. In spite of the design of the prosthesis itself, the degree of flexion attainable following TKA depends on a variety of factors, such as the joint's preoperative condition/flexion, muscle strength, and surgical technique. High-flexion knee prostheses have been developed to accommodate movements that require greater flexion than typically achievable with conventional TKA; such high flexion is especially prevalent in Asian cultures. Recently, computational techniques have been widely used for evaluating the functionality of knee prostheses and for improving biomechanical performance. To offer a better understanding of the development and evaluation techniques currently available, this paper aims to review some of the latest trends in the simulation of high-flexion knee prostheses.

Subtracting-adding strategy for necrotic lesion segmentation in osteonecrosis of the femoral head.

PURPOSE: Osteonecrosis of the femoral head (ONFH) is a severe bone disease that can progressively lead to hip dysfunction. Accurately segmenting the necrotic lesion helps in diagnosing and treating ONFH. This paper aims at enhancing deep learning models for necrosis segmentation. METHODS: Necrotic lesions of ONFH are confined to the femoral head. Considering this domain knowledge, we introduce a preprocessing procedure, termed the "subtracting-adding" strategy, which explicitly incorporates this domain knowledge into the downstream deep neural network input. This strategy first removes the voxels outside the predefined volume of interest to "subtract" irrelevant information, and then it concatenates the bone mask with raw data to "add" anatomical structure information. RESULTS: Each of the tested off-the-shelf networks performed better with the help of the "subtracting-adding" strategy. The dice similarity coefficients increased by 10.93%, 9.23%, 9.38% and 1.60% for FCN, HRNet, SegNet and UNet, respectively. The improvements in FCN and HRNet were statistically significant. CONCLUSIONS: The "subtracting-adding" strategy enhances the performance of general-purpose networks in necrotic lesion segmentation. This strategy is compatible with various semantic segmentation networks, alleviating the need to design task-specific models.

The Structure, Biology, and Mechanical Function of Tendon/Ligament-Bone Interfaces.

After tendon or ligament reconstruction, the interface between the hard bone and soft connective tissue is considerably weakened and is difficult to restore through healing. The tendon/ligament-bone interface is mechanically the weakest point under tensile loading and is often the source of various postoperative complications, such as bone resorption and graft laxity. A comprehensive understanding of the macro- and microfeatures of the native tendon/ligament-bone interface would be beneficial for developing strategies for regenerating the tissue. This article discusses the structural, biological, and mechanical features of the tendon/ligament-bone interfaces and how these can be affected by aging and loading conditions.

ACL reconstruction combined with anterolateral structures reconstruction for treating ACL rupture and knee injuries: a finite element analysis.

Introduction: The biomechanical indication for combining anterolateral structures reconstruction (ASLR) with ACL reconstruction (ACLR) to reduce pivot shift in the knee remains unclear. This study aims to investigate knee functionality after ACL rupture with different combinations of injuries, and to compare the effectiveness of ALSR with ACLR for treating these injuries. Methods: A validated finite element model of a human cadaveric knee was used to simulate pivot shift tests on the joint in different states, including 1) an intact knee; 2) after isolated ACL rupture; 3) after ACL rupture combined with different knee injuries or defect, including a posterior tibial slope (PTS) of 20°, an injury to the anterolateral structures (ALS) and an injury to the posterior meniscotibial ligament of the lateral meniscus (LP); 4) after treating the different injuries using isolated ACLR; v. after treating the different injuries using ACLR with ALSR. The knee kinematics, maximum von Mises stress (Max.S) on the tibial articular cartilage (TC) and force in the ACL graft were compared among the different simulation groups. Results and discussion: Comparing with isolated ACL rupture, combined injury to the ALS caused the largest knee laxity, when a combined PTS of 20° induced the largest Max.S on the TC. The joint stability and Max.S on the TC in the knee with an isolated ACL rupture or a combined rupture of ACL and LP were restored to the intact level after being treated with isolated ACLR. The knee biomechanics after a combined rupture of ACL and ALS were restored to the intact level only when being treated with a combination of ACLR and ALSR using a large graft diameter (6 mm) for ALSR. However, for the knee after ACL rupture combined with a PTS of 20°, the ATT and Max.S on the TC were still greater than the intact knee even after being treated with a combination of ACLR and ALSR. The finite element analysis showed that ACLR should include ALSR when treating ACL ruptures accompanied by ALS rupture. However, pivot shift in knees with a PTS of 20° was not eliminated even after a combined ACLR and ALSR.

Genetic and Modifiable Risk Factors for Postoperative Complications of Total Joint Arthroplasty: A Genome-Wide Association and Mendelian Randomization Study.

Background: Total joint arthroplasty (TJA) is an orthopedic procedure commonly used to treat damaged joints. Despite the efficacy of TJA, postoperative complications, including aseptic prosthesis loosening and infections, are common. Moreover, the effects of individual genetic susceptibility and modifiable risk factors on these complications are unclear. This study analyzed these effects to enhance patient prognosis and postoperative management. Methods: We conducted an extensive genome-wide association study (GWAS) and Mendelian randomization (MR) study using UK Biobank data. The cohort included 2964 patients with mechanical complications post-TJA, 957 with periprosthetic joint infection (PJI), and a control group of 398,708 individuals. Genetic loci associated with postoperative complications were identified by a GWAS analysis, and the causal relationships of 11 modifiable risk factors with complications were assessed using MR. Results: The GWAS analysis identified nine loci associated with post-TJA complications. Two loci near the PPP1R3B and RBM26 genes were significantly linked to mechanical complications and PJI, respectively. The MR analysis demonstrated that body mass index was positively associated with the risk of mechanical complications (odds ratio [OR]: 1.42; p < 0.001). Higher educational attainment was associated with a decreased risk of mechanical complications (OR: 0.55; p < 0.001) and PJI (OR: 0.43; p = 0.001). Type 2 diabetes was suggestively associated with mechanical complications (OR, 1.18, p = 0.02), and hypertension was suggestively associated with PJI (OR, 1.41, p = 0.008). Other lifestyle factors, including smoking and alcohol consumption, were not causally related to postoperative complications. Conclusions: The genetic loci near PPP1R3B and RBM26 influenced the risk of post-TJA mechanical complications and infections, respectively. The effects of genetic and modifiable risk factors, including body mass index and educational attainment, underscore the need to perform personalized preoperative assessments and the postoperative management of surgical patients. These results indicate that integrating genetic screening and lifestyle interventions into patient care can improve the outcomes of TJA and patient quality of life.

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.