Prosthesis loosening is the leading cause of postoperative revision in unicompartmental knee arthroplasty (UKA). The deviation of medial and lateral translational installation of the prosthesis during surgery is a common clinical phenomenon and an important factor in increasing the risk of prosthesis loosening. This study established a UKA finite element model and a bone-prosthesis fixation interface micromotion prediction model. The predicted medial contact force and joint motion of the knee joint from a patient-specific lower extremity musculoskeletal multibody dynamics model of UKA were used as boundary conditions. The effects of 9 femoral component medial and lateral translational installation deviations on the Von Mises stress of the proximal tibia, the contact stress, and the micro-motion of the bone prosthesis fixation interface were quantitatively studied. It was found that compared with the neutral position (a/A of 0.492), the lateral translational deviation of the femoral component significantly increased the tibial Von Mises stress and the bone-prosthesis fixation interface contact stress. The maximum Von Mises stress and the maximum contact stress of the fixation interface increased by 14.08% and 143.15%, respectively, when a/A was 0.361. The medial translational deviation of the femoral component significantly increased the bone-prosthesis fixation interface micro-motion. The maximum value of micromotion under the conditions of femoral neutral and medial translation deviation was in the range of 20-50 μm, which is suitable for osseointegration. Therefore, based on considerations such as the micromotion range suitable for osseointegration reported in the literature, the risk of reducing prosthesis loosening, and factors that may induce pain, it is recommended that clinicians control the mounting position of the femoral component during surgery within the safe range of 0-4 mm medial translation deviation.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Finite Element Analysis ; Biomechanical Phenomena ; Knee Prosthesis ; Tibia/surgery* ; Femur/surgery* ; Stress, Mechanical ; Prosthesis Failure ; Knee Joint/surgery* ; Prosthesis Design

Aiming at the problems of low accuracy and large difference of segmentation boundary distance in anterior cruciate ligament (ACL) image segmentation of knee joint, this paper proposes an ACL image segmentation model by fusing dilated convolution and residual hybrid attention U-shaped network (DRH-UNet). The proposed model builds upon the U-shaped network (U-Net) by incorporating dilated convolutions to expand the receptive field, enabling a better understanding of the contextual relationships within the image. Additionally, a residual hybrid attention block is designed in the skip connections to enhance the expression of critical features in key regions and reduce the semantic gap, thereby improving the representation capability for the ACL area. This study constructs an enhanced annotated ACL dataset based on the publicly available Magnetic Resonance Imaging Network (MRNet) dataset. The proposed method is validated on this dataset, and the experimental results demonstrate that the DRH-UNet model achieves a Dice similarity coefficient (DSC) of (88.01±1.57)% and a Hausdorff distance (HD) of 5.16±0.85, outperforming other ACL segmentation methods. The proposed approach further enhances the segmentation accuracy of ACL, providing valuable assistance for subsequent clinical diagnosis by physicians.
Humans ; Magnetic Resonance Imaging/methods* ; Anterior Cruciate Ligament/diagnostic imaging* ; Image Processing, Computer-Assisted/methods* ; Knee Joint/diagnostic imaging* ; Neural Networks, Computer ; Algorithms ; Deep Learning

Although metal blocks have been widely used for reconstructing uncontained tibial bone defects, the influence of their elastic modulus on the stability of tibial prosthesis fixation remains unclear. Based on this, a finite element model incorporating constrained condylar knee (CCK) prosthesis, tibia, and metal block was established. Considering the influence of the post-restraint structure of the prosthesis, the effects of variations in the elastic modulus of the block on the von Mises stress distribution in the tibia and the block, as well as on the micromotion at the bone-prosthesis fixation interface, were investigated. Results demonstrated that collision between the insert post and femoral prosthesis during tibial internal rotation increased tibial von Mises stress, significantly influencing the prediction of block elastic modulus variation. A decrease in the elastic modulus of the metal block resulted in increased von Mises stress in the proximal tibia, significantly reduced von Mises stress in the distal tibia, decreased von Mises stress of the block, and increased micromotion at the bone-prosthesis fixation interface. When the elastic modulus of the metal block fell below that of bone cement, inadequate block support substantially increased the risk of stress shielding in the distal tibia and fixation interface loosening. Therefore, this study recommends that biomechanical investigations of CCK prostheses must consider the post-constraint effect, and the elastic modulus of metal blocks for bone reconstruction should not be lower than 3 600 MPa.
Knee Prosthesis ; Humans ; Finite Element Analysis ; Tibia/surgery* ; Elastic Modulus ; Arthroplasty, Replacement, Knee/methods* ; Stress, Mechanical ; Metals ; Prosthesis Design ; Knee Joint/surgery* ; Biomechanical Phenomena

Revision of anterior cruciate ligament (ACL) reconstruction is more challenging than primary ACL reconstruction and often yields less favorable outcomes. The European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) has established a consensus regarding preoperative diagnosis, assessment, and selection criteria for ACL revision surgery. This consensus addresses 18 key issues that are most pertinent to clinical practice, providing guiding recommendations aimed at improving the prognosis of ACL revisions.
Humans ; Anterior Cruciate Ligament Reconstruction/methods* ; Arthroscopy/methods* ; Anterior Cruciate Ligament Injuries ; Societies, Medical ; Reoperation ; Consensus ; Anterior Cruciate Ligament/surgery* ; Europe ; Sports Medicine ; Knee Injuries/surgery* ; Knee Joint/surgery*

OBJECTIVE: To evaluate the early effectiveness of navigation-free robot-assisted total knee arthroplasty (TKA) compared to traditional TKA in the treatment of knee osteoarthritis combined with extra-articular deformities. METHODS: The clinical data of 30 patients with knee osteoarthritis combined with extra-articular deformities who met the selection criteria between June 2019 and January 2024 were retrospectively analyzed. Fifteen patients underwent CORI navigation-free robot-assisted TKA and intra-articular osteotomy (robot group) and 15 patients underwent traditional TKA and intra-articular osteotomy (traditional group). There was no significant difference in age, gender, body mass index, affected knee side, extra-articular deformity angle, deformity position, deformity type, and preoperative knee range of motion, American Knee Society (KSS) knee score and KSS function score, and lower limb alignment deviation between the two groups ( P>0.05). The operation time, intraoperative blood loss, and complications of the two groups were recorded and compared. The knee range of motion and lower limb alignment deviation were recorded before operation and at 6 months after operation, and the knee joint function was evaluated by KSS knee score and function score. RESULTS: There was no significant difference in operation time between the two groups ( P>0.05); the intraoperative blood loss in the robot group was significantly less than that in the traditional group ( P<0.05). Patients in both groups were followed up 6-12 months, with an average of 8.7 months. The incisions of all patients healed well, and there was no postoperative complication such as thrombosis or infection. At 6 months after operation, X-ray examination showed that the position of the prosthesis was good in both groups, and there was no loosening or dislocation of the prosthesis. The knee joint range of motion, the lower limb alignment deviation, and the KSS knee score and KSS function score significantly improved in both groups ( P<0.05) compared to preoperative ones. The changes of lower limb alignment deviation and KSS function score between pre- and post-operation in the robot group were significantly better than those in the traditional group ( P<0.05), while the changes of other indicators between pre- and post-operation in the two groups were not significant ( P>0.05). CONCLUSION Compared to traditional TKA, navigation-free robot-assisted TKA for knee osteoarthritis with extra-articular deformities results in less intraoperative blood loss, more precise reconstruction of lower limb alignment, and better early effectiveness. However, long-term effectiveness require further investigation.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Osteoarthritis, Knee/surgery* ; Robotic Surgical Procedures/methods* ; Male ; Female ; Retrospective Studies ; Range of Motion, Articular ; Middle Aged ; Aged ; Treatment Outcome ; Osteotomy/methods* ; Knee Joint/physiopathology* ; Operative Time

OBJECTIVE: To investigate the effectiveness of modified single patellar tunnel medial patella femoral ligament (MPFL) reconstruction in the treatment of recurrent patellar dislocation. METHODS: Between January 2023 and June 2023, a total of 61 patients with recurrent patellar dislocation who underwent MPFL reconstruction with autologous semitendinosus were enrolled and divided into 2 groups using random number table method. In the patellar anchor group, 31 patients were treated with MPFL reconstruction with double medial patellar anchors, and 30 patients in the patellar tunnel group were treated with MPFL reconstruction with single patellar tunnel. The femoral ends of both groups were fixed with absorbable compression screws. There was no significant difference in baseline data such as gender, age, side, tibial tubercle-trochlear groove (TT-TG), Q angle, Caton-Deschamps index, number of dislocation, and preoperative Kujala score, preoperative patellar inclination angle ( P>0.05). Patellar tunnel, patellar anchor position, patellar reduction, and the patellar inclination angle were measured by CT scan after operation. Kujala score was used to evaluate the function of knee joint before operation, at 2 weeks and 1, 3, 6, 12 months after operation. Incision aesthetic satisfaction score was performed at 3 months after operation. The signal-to-noise quotient (SNQ) of the transplanted tendon was measured by knee MRI at 12 months after operation to compare the maturity of the graft between the two groups. RESULTS: There was no significant difference in operation time and intraoperative blood loss between the two groups ( P>0.05). Knee CT reexamination showed that the patellar tunnel and the patellar anchor position were consistent with the intraoperative fluoroscopy. There was no significant difference in the difference of the patellar inclination angle between the two groups before and after operation ( P>0.05). All patients were followed up 12-14 months (mean, 12.8 months). There was 1 case of patellar anchor suture rejection in patellar anchor group, and the wound healed after debridement and dressing change. During the follow-up, there was no complication such as recurrence of patellar dislocation, infection and postoperative stiffness. The Kujala scores of the two groups significantly improved at each time point after 1 month of operation when compared with those before operation ( P<0.05), and the Kujala scores of the two groups returned to normal levels at 3 months after operation. The Kujala score in the patellar tunnel group was significantly higher than that in the patellar anchor group in the very early stage (2 weeks) ( P<0.05), and there was no significant difference between the two groups at other time points ( P>0.05). Patients in the patellar tunnel group were significantly better than those in the patellar anchor group in the score of incision aesthetic satisfaction at 3 months after operation and the SNQ at 12 months after operation ( P<0.05). CONCLUSION Modified single patellar tunnel MPFL reconstruction was used to treat patients with recurrent patellar dislocation without pathological TT-TG. The slide-fixation structure formed by single patellar tunnel positioning provides a variable degree of freedom for the reconstructed MPFL, which shows good effectiveness in the very early stage of the rehabilitation process.
Humans ; Patellar Dislocation/surgery* ; Male ; Female ; Plastic Surgery Procedures/methods* ; Adult ; Patellar Ligament/surgery* ; Recurrence ; Treatment Outcome ; Young Adult ; Adolescent ; Patella/surgery* ; Suture Anchors ; Hamstring Tendons/transplantation* ; Knee Joint/surgery* ; Transplantation, Autologous

OBJECTIVE: To explore the feasibility and effectiveness of suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique for avulsion fractures of the inferior pole of the patella. METHODS: A clinical data of 38 patients with avulsion fractures of the inferior pole of the patella, who met the selective criteria and were admitted between September 2021 and April 2023, was retrospectively analyzed. The fractures were treated with suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique in 18 cases (group A) and steel wire tension-band fixation in 20 cases (group B). There was no significant difference in terms of age, gender, cause of fracture, side of fracture, and disease duration between the two groups ( P>0.05). The length of incision, operation time, occurrence of complications, the range of motion of knee joint, and Böstman score of knee joint at last follow-up were recorded. The fracture healing was evaluated through X-ray films and the time of fracture healing was recorded. RESULTS: All incisions healed by first intention. The length of incision was significantly shorter in group A than in group B ( P<0.05). There was no significant difference in the operation time between the two groups ( P>0.05). All patients were followed up 12-24 months (mean, 16.1 months). X-ray films showed that all fractures healed and there was no significant difference in the healing time between the two groups ( P>0.05). At last follow-up, the range of motion and Böstman score of the knee joint in group A were significantly better than those in group B ( P<0.05). During follow-up, 1 patient (5.6%) in group A had one anchor mild prolapse and 3 patients (15.0%) occured internal fixation irritation in group B. But there was no significant difference in the incidence of complications between the two groups ( P>0.05). CONCLUSION For the avulsion fractures of the inferior pole of the patella, the suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique has advantages of reliable fixation, small incision, avoidance of secondary operation to remove internal fixator, and fewer complications, with definite effectiveness.
Humans ; Male ; Female ; Patella/surgery* ; Suture Anchors ; Fracture Fixation, Internal/instrumentation* ; Adult ; Retrospective Studies ; Middle Aged ; Fractures, Avulsion/surgery* ; Treatment Outcome ; Young Adult ; Range of Motion, Articular ; Fracture Healing ; Adolescent ; Suture Techniques ; Knee Joint/physiopathology*

OBJECTIVE: To measure and analyze the relationships among the posterior tibial slope (PTS), meniscal slope (MS), and meniscus posterior horn thickness (MPHT) of the medial and lateral tibial plateau in healthy people and patients with anteromedial osteoarthritis (AMOA) in Heilongjiang province, so as to provide reference basis for appropriate tibial osteotomy and prosthesis placement angles in knee joint surgeries. METHODS: A retrospective collection of imaging data from knee joint MRI examinations conducted prior to AMOA for various reasons was performed. A total of 103 healthy individuals (healthy group) and 30 AMOA patients (AMOA group) were included. There was no significant difference in the gender composition ratio, side, and body mass index between the two groups ( P>0.05); however, the comparison of ages between the two groups showed a significant difference ( P<0.05). The collected DICOM format image data was imported into the RadiAnt DICOM Viewer software and measured the medial PTS (MPTS), lateral PTS (LPTS), medial MS (MMS), lateral MS (LMS), medial MPHT (MMPHT), and lateral MPHT (LMPHT) with standard methods. The differences of the above indexes between the two groups and between different genders and sides in the two groups were compared, and Pearson correlation analysis was carried out. At the same time, the measured data of healthy group were compared with the relevant literature reported in the past. RESULTS: Compared to the healthy group, the AMOA group exhibited significantly smaller MPTS and LPTS, as well as significantly greater MMPHT and LMPHT, with significant differences ( P<0.05). However, there was no significant difference in the MMS and LMS between the two groups ( P>0.05). The differences in various indicators between genders and sides within the two groups were not significant ( P>0.05). The correlation analysis and regression curves indicated that both MPTS and LPTS in the two groups were positively correlated with their respective ipsilateral MS and MPHT ( P<0.05); as PTS increased, the rate of increase in MS and MPHT tend to plateau. Compared to previous related studies, the MPTS and LPTS measured in healthy group were comparable to those of the Turkish population, exhibiting smaller values than those reported in other studies, while MMS and LMS were relatively larger, and MMPHT and LMPHT were smaller. CONCLUSION In healthy people and AMOA patients in Heilongjiang province, PTS has great individual differences, but there is no significant individual difference in MS. MPHT can play a certain role in retroversion compensation, and its thickness increase may be used as one of the indicators to predict the progression of AMOA. The above factors should be taken into account when UKA is performed, and the posterior tilt angle of tibial osteotomy should be set reasonably after preoperative examination and evaluation.
Humans ; Osteoarthritis, Knee/surgery* ; Retrospective Studies ; Tibia/pathology* ; Male ; Female ; Adult ; Menisci, Tibial/anatomy & histology* ; China ; Knee Joint/pathology* ; Magnetic Resonance Imaging ; Middle Aged ; Aged ; Osteotomy

OBJECTIVE: To investigate the effectiveness of digital three-dimensional (3D) printing osteotomy guide plate assisted total knee arthroplasty (TKA) in treatment of knee osteoarthritis (KOA) patients with femoral internal implants. METHODS: The clinical data of 55 KOA patients who met the selection criteria between July 2021 and October 2023 were retrospectively analyzed. Among them, 26 cases combined with femoral implants were treated with digital 3D printing osteotomy guide plate assisted TKA (guide plate group), and 29 cases were treated with conventional TKA (control group). There was no significant difference in gender, age, body mass index, side, Kellgren-Lawrence classification, preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) knee score, knee range of motion, and other baseline data between the two groups ( P>0.05). The operation time, intraoperative blood loss, incision length, postoperative first ambulation time, surgical complications; VAS score, knee HSS score, knee range of motion before operation, at 1 week and 3 months after operation, and at last follow-up; distal femoral lateral angle, proximal tibial medial angle, hip-knee-ankle angle and other imaging indicators at last follow-up were recorded and compared between the two groups. RESULTS: The operation time, incision length, intraoperative blood loss, and postoperative first ambulation time in the guide plate group were significantly lower than those in the control group ( P<0.05). In the control group, there were 1 case of incision rupture and bleeding and 1 case of lower limb intermuscular venous thrombosis, which was cured after symptomatic treatment. There was no complication such as neurovascular injury, incision infection, or knee prosthesis loosening in both groups. Patients in both groups were followed up 12-26 months, with an average of 16.25 months. The VAS score, HSS score, and knee range of motion improved at each time point after operation in both groups, and further improved with time after operation, the differences were significant ( P<0.05). The above indicators in the guide plate group were significantly better than those in the control group at 1 week and 3 months after operation ( P<0.05), and there was no significant difference between the two groups at last follow-up ( P>0.05). At last follow-up, the distal femoral lateral angle, the proximal tibial medial angle, and the hip-knee-ankle angle in the guide plate group were significantly better than those in the control group ( P<0.05). CONCLUSION The application of digital 3D printing osteotomy guide plate assisted TKA in the treatment of KOA patients with femoral implants can simplify the surgical procedures, overcome limitations of conventional osteotomy guides, reduce surgical trauma, achieve individualized and precise osteotomy, and effectively restore lower limb alignment and knee joint function.
Humans ; Arthroplasty, Replacement, Knee/instrumentation* ; Osteoarthritis, Knee/surgery* ; Osteotomy/instrumentation* ; Male ; Retrospective Studies ; Female ; Printing, Three-Dimensional ; Femur/surgery* ; Middle Aged ; Bone Plates ; Range of Motion, Articular ; Aged ; Treatment Outcome ; Surgery, Computer-Assisted/methods* ; Knee Prosthesis ; Knee Joint/surgery* ; Operative Time

OBJECTIVE: To investigate the impact of bone mass and volume of low-density zones beneath the tibial plateau on the maximum von Mises stresses experienced by the cartilage and meniscus in the knee joint. METHODS: The study included one healthy adult volunteer, from whom CT scans were obtained, and one patient diagnosed with knee osteoarthrisis (KOA), for whom X-ray films were acquired. A static model of the knee joint featuring a low-density zone was established based on a normal knee model. In the finite element analysis, axial loads of 1 000 N and 1 800 N were applied to the weight-bearing region of the upper surface of the femoral head for model validation and subsequent finite element studies, respectively. The maximum von Mises stresses in the femoral cartilage, as well as the medial and lateral tibial cartilage and menisci, were observed, and the stress percentage of the medial and lateral components were concurrently analyzed. Additionally, HE staining, as well as alkaline magenta staining, were performed on the pathological specimens of patients with KOA in various low-density regions. RESULTS: The results of model validation indicated that the model was consistent with normal anatomical structures and correlated with previous calculations documented in the literature. Static analysis revealed that the maximum von Mises stress in the medial component of the normal knee was the lowest and increased with the advancement of the hypointensity zone. In contrast, the lateral component exhibited an opposing trend, with the maximum von Mises stress in the lateral component being the highest and decreasing as the hypointensity zone progressed. Additionally, the medial component experienced an increasing proportion of stress within the overall knee joint. HE staining demonstrated that the chondrocyte layer progressively deteriorated and may even disappear as the hypointensity zone expanded. Furthermore, alkaline magenta staining indicated that the severity of microfractures in the trabecular bone increased concurrently with the expansion of the hypointensity zone. CONCLUSION The presence of subtalar plateau low-density zone may aggravate joint degeneration. In clinical practice, it is necessary to pay attention to the changes in the subtalar plateau low-density zone and actively take effective measures to strengthen the bone status of the subtalar plateau low-density zone and restore the complete biomechanical function of the knee joint, in order to slow down or reverse the progression of osteoarthritis.
Humans ; Finite Element Analysis ; Knee Joint/physiology* ; Tibia/anatomy & histology* ; Cartilage, Articular/physiology* ; Menisci, Tibial/physiopathology* ; Tomography, X-Ray Computed ; Osteoarthritis, Knee/diagnostic imaging* ; Weight-Bearing ; Bone Density ; Adult ; Stress, Mechanical ; Male ; Middle Aged ; Biomechanical Phenomena ; Female