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 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 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

OBJECTIVE: To investigate the effect of femoral condyle sliding osteotomy (FCSO) on the flexion gap and external rotation of the prosthesis in balancing coronal instability during initial total knee arthroplasty (TKA). METHODS: Between November 2021 and October 2024, FCSO technique was applied to balance the coronal medial and lateral spaces during initial TKA in 3 patients, including medial condyle sliding osteotomy (MCSO) and lateral condyle sliding osteotomy (LCSO). There were 1 male and 2 females with the age of 81, 68, and 68 years old. The affected knee has varus or valgus deformity, with tibia-femoral angles of 169.7°, 203.3°, and 162.2°, respectively. The hip-knee-ankle angle (HKA), range of motion (ROM), knee society scoring system (KSS), and pain visual analogue scale (VAS) score were used to evaluate joint function and pain relief. Based on model bone, the thickness and bone bed area of the medial and lateral femoral condyle osteotomy blocks in FCSO were measured. During TKA in 12 patients, the range of osteotomy block movement was evaluated. By simplifying the upward and forward movement of the osteotomy block into a geometric model, the impact of movement on the flexion gap and external rotation of the prosthesis was calculated. RESULTS: After application of FCSO during TKA, the limb alignment and medial and lateral balance at extension and flexion positions were restored in 3 patients. Three patients were followed up 23, 11, and 3 months, respectively. Postoperative HKA, pain VAS score, KSS score, and ROM all showed significant improvement compared to preoperative levels. The maximum thickness of osteotomy blocks by MCSO and LCSO was 17 and 12 mm, respectively. The simple upward movement of the osteotomy block mainly affected the extension gap, and had little effect on the flexion gap and external rotation of the prosthesis. Moving the osteotomy block forward at the same time had a significant impact on the flexion gap and external rotation of the prosthesis, especially on LCSO. Mild forward movement leaded to a decrease in external rotation of more than 3°, which had a serious impact on the patellar trajectory. CONCLUSION FCSO can effectively solve the problem of imbalance between the medial and lateral spaces during initial TKA, avoiding knee joint instability caused by excessive loosening and limiting the use of constrained condylar prosthesis. The distance for the downward movement of the osteotomy block in MCSO and LCSO was 3-5 mm and 6-8 mm, respectively, with 10-15 mm of space for forward movement and almost no space for backward movement. For MCSO, the upward and forward movement of the osteotomy block will increase the external rotation of the prosthesis, which is beneficial for improving the patellar trajectory and suitable for valgus knee. LCSO is suitable for varus knee, and the osteotomy block only slides vertically up and down without moving forward and backward.
Humans ; Osteotomy/methods* ; Male ; Female ; Arthroplasty, Replacement, Knee/methods* ; Aged ; Range of Motion, Articular ; Femur/surgery* ; Knee Joint/physiopathology* ; Aged, 80 and over ; Knee Prosthesis ; Treatment Outcome ; Osteoarthritis, Knee/surgery*

OBJECTIVE: To explore the effectiveness of the modified Lemaire procedure in anterior cruciate ligament reconstruction (ACLR) in patients with a highly positive pivot shift test. METHODS: The clinical data of 18 patients with anterior cruciate ligament (ACL) rupture and highly positive pivot shift test between April 2020 and September 2022 were retrospectively analyzed. There were 13 males and 5 females with an average age of 28.3 years (range, 17-41 years). Causes of injury included 11 cases of direct violence injury, including 6 cases of traffic accident injury, 4 cases of sports injury, 1 case of falling injury; 7 cases of indirect violence injury, all sports injury. All patients had complete ACL rupture, including 15 acute injuries and 3 old injuries. The preoperative pivot shift test was grade Ⅱ in 9 cases and grade Ⅲ in 9 cases. All patients were treated with ACLR combined with modified Lemaire procedure. The International Knee Documentation Committee (IKDC) score and Lysholm score were used to evaluate the effectiveness before operation and at 3, 6, 12 months after operation. KT-2000 arthrometer was used to measure the anterior stability of the knee joint, and the difference between the healthy and affected sides was recorded. Pivot shift test was used to evaluate the rotational stability of the knee joint. During the follow-up, X-ray films were taken to observe the bone tunnel and internal fixation, and MRI was used to examine the healing of ACL, anterolateral collateral ligament and fibular collateral ligament grafts. RESULTS: All patients completed the operation successfully without complications such as knee joint infection, vascular and nerve injury. All patients were followed up 12-19 months (mean, 13.2 months). After operation, the rotational stability of the knee joint recovered satisfactorily, and there was no adverse symptom such as knee instability and locking at last follow-up. X-ray film and MRI showed that the bone tunnel was anatomically located and healed well, the internal fixation was in good position, and the reconstructed ACL and iliotibial band were continuous and in good tension. The IKDC score, Lysholm score, and the difference of KT-2000 between the healthy and the affected sides significantly improved at 3, 6, and 12 months after operation ( P<0.05). All the indicators further improved with time after operation, except that there was no significant difference in IKDC score between 3 and 6 months after operation and in the difference of KT-2000 between 3 months and 6, 12 months after operation ( P>0.05), and there were significant differences in other indicators between different time points ( P<0.05). Pivot shift test was negative immediately after operation and at last follow-up. CONCLUSION In ACL injuries with a highly positive pivot shift test, ACLR combined with the modified Lemaire procedure can effectively restore anterolateral knee stability, leading to satisfactory knee stability and function in the early postoperative period.
Humans ; Anterior Cruciate Ligament Reconstruction/methods* ; Male ; Female ; Anterior Cruciate Ligament Injuries/physiopathology* ; Adult ; Adolescent ; Retrospective Studies ; Young Adult ; Anterior Cruciate Ligament/surgery* ; Treatment Outcome ; Joint Instability/surgery* ; Knee Joint/physiopathology* ; Range of Motion, Articular

OBJECTIVE: To investigate the biomechanical characteristics of Schatzker type Ⅱ tibial plateau fracture fixed by different bone grafting methods and internal fixations. METHODS: Twenty-four embalmed specimens of adult knee joint were selected to make Schatzker type Ⅱ tibial plateau fracture models, which were randomly divided into 8 groups (groups A1-D1 and groups A2-D2, n=3). After all the fracture models were restored, non-structural iliac crest bone grafts were implanted in group A1-D1, and structural iliac crest bone grafts in groups A2-D2. Following bone grafting, group A was fixed with a lateral golf locking plate, group B was fixed with lateral golf locking plate combined compression bolt, group C was fixed with lateral tibial "L"-shaped locking plate, and group D was fixed with lateral tibial "L"-shaped locking plate combined compression bolt. Compression and cyclic loading tests were performed on a biomechanical testing machine. A distal femur specimen or a 4-cm-diameter homemade bone cement ball were used as a pressure application mould for each group of models. The specimens were loaded with local compression at a rate of 10 N/s and the mechanical loads were recorded when the vertical displacement of the split bone block reached 2 mm. Then, compressive and cyclic loading tests were conducted on the fixed models of each group. The specimens were compression loaded to 100, 400, 700, and 1 000 N at a speed of 10 N/s to record the vertical displacement of the split bone block. The specimens were also subjected to cyclic loading at 5 Hz and 10 N/s within the ranges 100-300, 100-500, 100-700, and 100-1 000 N to record the vertical displacement of the split bone block at the end of the entire cyclic loading test. The specimens were subjected to cyclic loading tests and the vertical displacement of the split bone block was recorded at the end of the test. RESULTS: When the vertical displacement of the collapsed bone block reached 2 mm, the mechanical load of groups A2-D2 was significantly greater than that of groups A1-D1 ( P<0.05). The mechanical load of groups B and D was significantly greater than that of group A under the two bone grafting methods ( P<0.05); the local mechanical load of group D was significantly greater than that of groups B and C under the structural iliac crest bone grafts ( P<0.05). There was no significant difference ( P>0.05) in the vertical displacement of the split bone blocks between the two bone graft methods when the compressive load was 100, 400, 700 N and the cyclic load was 100-300, 100-500, 100-700 N in groups A-D. However, the vertical displacement of bone block in groups A1-D1 was significantly greater than that in groups A2-D2 ( P<0.05) when the compressive loading was 1 000 N and the cyclic load was 100-1 000 N. The vertical displacement of bone block in group B was significantly smaller than that in group A, and that in group D was significantly smaller than that in group C under the same way of bone graft ( P<0.05). CONCLUSION Compared with non-structural iliac crest bone grafts implantation, structural iliac crest bone grafts is more effective in preventing secondary collapse of Schatzker type Ⅱ tibial plateau fracture, and locking plate combined with compression bolt fixation can provide better articular surface support and resistance to axial compression, and the lateral tibial "L"-shaped locking plate can better highlight its advantages of "raft" fixation and show better mechanical stability.
Humans ; Bone Transplantation/methods* ; Tibial Fractures/physiopathology* ; Fracture Fixation, Internal/instrumentation* ; Biomechanical Phenomena ; Bone Plates ; Ilium/transplantation* ; Adult ; Tibia/surgery* ; Bone Cements ; Knee Joint/surgery* ; Male ; Tibial Plateau Fractures

OBJECTIVE: To investigate the effectiveness and safety of simultaneous bilateral total knee athroplasty (SB-TKA) for the treatment of patients aged 65 years and younger with bilateral knee osteoarthritis (KOA) by comparing with patients undergoing unilateral total knee arthroplasty (U-TKA). METHODS: A clinical data of patients, who underwent primary TKA for KOA and met the selection criteria between June 2019 and July 2023, was retrospectively analyzed, including 181 patients in the U-TKA group and 52 patients in the SB-TKA group. The baseline data of age, gender, disease duration, body mass index, and preoperative hemoglobin (Hb), knee range of motion (ROM), Oxford knee score (OKS), and visual analogue scale (VAS) score for pain were compared between the two groups, with no significant difference ( P>0.05). The operation time, postoperative hospital stay, and all complications related to knee arthroplasty were recorded. Hb was measured at 2 days after operation and the difference between pre- and post-operation was calculated. The knee function and pain were evaluated by using ROM, OKS score, and VAS score and compared between the two groups. RESULTS: The operation time and postoperative hospital stay duration were significantly shorter in the U-TKA group than in the SB-TKA group ( P<0.05). The difference of Hb was significantly lower in the U-TKA group ( P<0.05). All patients were followed up 12-61 months (mean, 37.2 months). There was no significant difference in follow-up time between the two groups ( P>0.05). At last follow-up, the ROM, OKS score, and VAS score of both groups were better than the preoperative ones, and the differences were significant ( P<0.05); there were significant differences between the two groups in the ROM and OKS score ( P<0.05), while no significant difference was found in the VAS score ( P>0.05). Mild complications were observed in 31 cases (17.13%) and severe complications in 3 cases (1.66%) in the U-TKA group, while mild complications were observed in 14 cases (26.92%) in the SB-TKA group, and no severe complication occurred. There was no significant difference in the incidences of mild and severe complications between the two groups ( P>0.05). CONCLUSION In patients aged 65 years and younger with bilateral KOA, knee function and mobility can significantly improved when treated by SB-TKA. While patients had lower postoperative knee mobility and function scores compared with U-TKA, there was no significant difference in pain scores or overall incidence of complication. Strict patient selection and scientific perioperative management are important to achieve good effectiveness after operation in patients with SB-TKA.
Humans ; Arthroplasty, Replacement, Knee/adverse effects* ; Male ; Female ; Retrospective Studies ; Osteoarthritis, Knee/physiopathology* ; Range of Motion, Articular ; Treatment Outcome ; Middle Aged ; Operative Time ; Length of Stay ; Knee Joint/physiopathology* ; Pain Measurement ; Postoperative Complications/epidemiology* ; Aged

OBJECTIVE: To investigate the load distribution on the more painful and less painful limbs in patients with mild-to-moderate and severe bilateral knee osteoarthritis (KOA) and explore the compensatory mechanisms in both limbs among bilateral KOA patients with different severity levels. METHODS: A total of 113 participants were enrolled between July 2022 and September 2023. This cohort comprised 43 patients with mild-to-moderate bilateral KOA (Kellgren-Lawrence grade 2-3), 43 patients with severe bilateral KOA (Kellgren-Lawrence grade 4), and 27 healthy volunteers (healthy control group). The visual analogue scale (VAS) score for pain, the Hospital for Special Surgery (HSS) score, passive knee range of motion (ROM), and hip-knee-ankle angle (HKA) were used to assess walking pain intensity, joint function, and lower limb alignment in KOA patients, respectively. Motion trajectories of reflective markers and ground reaction force data during walking were captured using a gait analysis system. Musculoskeletal modeling was then employed to calculate biomechanical parameters, including the peak knee adduction moment (KAM), KAM impulse, peak joint contact force (JCF), and peak medial/lateral contact forces (MCF/LCF). Statistical analyses were performed to compare differences in clinical and gait parameters between bilateral limbs. Additionally, one-dimensional statistical parametric mapping was utilized to analyze temporal gait data. RESULTS: Mild-to-moderate KOA patients showed the significantly higher HSS score (67.7±7.9) than severe KOA patients (51.9±8.9; t=8.747, P<0.001). The more painful limb in all KOA patients exhibited significantly greater HKA and higher VAS scores compared to the less painful limb ( P<0.05). While bilateral knee ROM did not differ significantly in mild-to-moderate KOA patients ( P>0.05), the severe KOA patients had significantly reduced ROM in the more painful limb versus the less painful limb ( P<0.05). Healthy controls showed no significant bilateral difference in any biomechanical parameters ( P>0.05). All KOA patients demonstrated longer stance time on the less painful limb ( P<0.05). Critically, severe KOA patients exhibited significantly higher peak KAM, KAM impulse, and peak MCF in the more painful limb ( P<0.05), while mild-to-moderate KOA patients showed the opposite pattern with lower peak KAM and KAM impulse in the more painful limb ( P<0.05) and a similar trend for peak MCF. CONCLUSION Patients with mild-to-moderate KOA effectively reduce load on the more painful limb through compensatory mechanisms in the less painful limb. Conversely, severe bilateral varus deformities in advanced KOA patients nullify compensatory capacity in the less painful limb, paradoxically increasing load on the more painful limb. This dichotomy necessitates personalized management strategies tailored to disease severity.
Humans ; Osteoarthritis, Knee/physiopathology* ; Range of Motion, Articular ; Male ; Female ; Middle Aged ; Biomechanical Phenomena ; Knee Joint/physiopathology* ; Pain Measurement ; Severity of Illness Index ; Aged ; Gait/physiology* ; Walking/physiology* ; Case-Control Studies ; Adult ; Weight-Bearing

OBJECTIVE: To review the research progress on the lower limb biomechanical characteristics of patients with discoid lateral meniscus (DLM) injury after surgery. METHODS: By searching relevant domestic and international research literature on DLM, the postoperative characteristics of knee joint movement biomechanics, tibiofemoral joint stress distribution, lower extremity force line, and patellofemoral joint changes in patients with DLM injury were summarized. RESULTS: Surgical treatment can lead to varying degrees of changes in the lower limb biomechanical characteristics of patients with DLM injury. Specifically, the kinematic biomechanics of the knee joint can significantly improve, but there are still problems such as extension deficits in the affected knee joint. The peak stress of the tibiofemoral joint decreases with the increase of the residual meniscus volume, and the degree of change is closely related to the residual meniscus volume. Preserving a larger volume of the meniscus, especially the anterior horn volume, helps to reduce stress concentration. The lower extremity force line will deviate outward after surgery, and the more meniscus is removed during surgery, the greater the change in the lower extremity force line after surgery. There are conditions such as cartilage degeneration, position and angle changes in the patellofemoral joint after surgery. CONCLUSION The changes in the lower limb biomechanical characteristics after DLM injury are closely related to the choice of surgical methods and rehabilitation programs. However, the mechanisms of biomechanical changes in multiple lower limb joints and individual differences still need to be further studied and clarified.
Humans ; Biomechanical Phenomena ; Tibial Meniscus Injuries/physiopathology* ; Menisci, Tibial/physiopathology* ; Knee Joint/surgery* ; Lower Extremity/physiopathology* ; Patellofemoral Joint/physiopathology* ; Range of Motion, Articular ; Knee Injuries/physiopathology*

OBJECTIVE: To summarize the research progress on knee laxity of biomechanics and prevention and treatment after posterior cruciate ligament (PCL) reconstruction. METHODS: The domestic and international literature on the prevention and treatment of knee laxity after PCL reconstruction in recent years was extensively reviewed and analyzed. RESULTS: Different degrees of knee laxity often occur after PCL reconstruction, which can lead to poor prognosis in patients. The causes are associated with a variety of factors, including abnormal graft remodeling (such as differences in healing time and biomechanics among different types of grafts), tunnel position deviation (such as graft wear caused by the "killer turn" effect), and mechanical factors in postoperative rehabilitation (such as improper early weight-bearing and range of motion). These factors may promote graft elongation, increase early posterior tibial translation, and thereby induce knee laxity. CONCLUSION While PCL reconstruction improves knee stability, it is crucial to focus on and prevent postoperative knee laxity. However, current surgical methods are limited by factors such as graft characteristics, surgical technique flaws, and rehabilitation protocols, and thus can not fully correct the issue of abnormal postoperative laxity. Surgical techniques and treatment strategies still need further improvement and optimization to enhance patients' postoperative outcomes and quality of life.
Humans ; Joint Instability/surgery* ; Posterior Cruciate Ligament Reconstruction/adverse effects* ; Posterior Cruciate Ligament/surgery* ; Knee Joint/physiopathology* ; Biomechanical Phenomena ; Range of Motion, Articular ; Postoperative Complications/prevention & control* ; Knee Injuries/surgery*