Objective To establish a finite element model of the knee joint based on coronal plane alignment of the knee (CPAK) typing method, and analyze the biomechanical characteristics of different types of knee joints.Methods The finite element models of the knee joint were established based on CT scan data of 6 healthy volunteers. There were 5 males and 1 female with an average age of 24.2 years (range, 23-25 years). There were 3 left knees and 3 right knees. According to the CPAK typing method, the knees were rated as types Ⅰ to Ⅵ. Under the same material properties, boundary conditions, and axial loading, biomechanical simulations were performed on the finite element model of the knee joint. Based on the Von Mises stress nephogram and displacement nephogram, the peak stresses of the meniscus, femoral cartilage, and tibial cartilage, and the displacement of the meniscus were compared among different types of knee joints. Results The constructed finite element model of the knee joint was verified to be effective, and the stress and displacement results were consistent with previous literature. Under the axial load of 1 000 N, the stress nephogram showed that the stress distribution of the medial and lateral meniscus and tibial cartilage of CPAK type Ⅲ knee joint was the most uneven. The peak stresses of the lateral meniscus and tibial cartilage were 9.969 6 MPa and 2.602 7 MPa, which were 173% and 165% of the medial side, respectively. The difference of peak stress between the medial and lateral femoral cartilage was the largest in type Ⅳ knee joint, and the medial was 221% of the lateral. The displacement nephogram showed that the displacement of the medial meniscus was greater than that of the lateral meniscus except for types Ⅲ and Ⅵ knee joints. The difference between medial and lateral meniscus displacement of type Ⅲ knee joint was the largest, the lateral was 170% of the medial. Conclusion In the same type of joint line obliquity (JLO), the medial and lateral stress distribution of the knee was more uniform in varus and neutral positions than in valgus position. At the same time, the distal vertex of JLO subgroup can help to reduce the uneven medial and lateral stress distribution of varus knee, but increase the uneven distribution of valgus knee.
Objective To investigate the rotational mismatch of total kneereplacement with medial 1/3 of tibial tuberosity as bony landmark in osteoarthritic patients with varus or valgus deformity. Methods Axial images on computed tomography of 62 knees (including 55 varus deformities and 7 valgus deformities) in 32 Chinese osteoarthritic patients who had total knee arthroplasty were analyzed, compared with that of 10 healthy knees. On images of the distal femur, the angle between the lines of surgical epicondylar axis(SEA) and posterior condylar axis was measured as posterior condylar angle (PCA), and on images of the proximal tibia, a baseline for the anteriorposterior axis of each component was drawn based on the SEA for the femur and the medial 1/3 of the tibial tuberosity for the tibia. The angle between these lines (Angle α) was defined as therotational mismatch between the components when they were aligned to the anatomic landmarks of each bone. Results The sulcus of medial epicondyle of femur could be identified on CT images of over 80% osteoarthritic knees; the median value of PCA was +2.36°, with an individual variation of 0° to +7.5°. Angle α was +6.45±3.68°(range, 0° to +11.8°) in 10 healthy knees, which increased significantly to +10.85±10.47°(range, 0° to +28.1°)in 55 varus knees (P＜0.05), which also increased significantly to +11.6±7.3°(range, -6.5° to +26.8°) in 7 valgus knees (P＜ 0.05). Conclusion With the medial 1/3 of the tibial tuberosity as the rotational landmark for the tibial component, there was a tendency to align the tibial component in external rotational position relative to the femoral component in knees with normal alignment, the rotational mismatch increased in Chinese osteoarthritic knees with varus and valgus deformity.
ObjectiveTo explore the nursing experience of preoperative treatment for urethral injury with ureteroscopic urethral realignment. MethodsThe key points of the nursing experience of preoperative treatment for 58 cases of urethral injury with ureteroscopic urethral realignment were retrospectively analyzed. The patients were treated between January 2008 and December 2012. ResultsUrethra catheterization of the 58 patients receiving the ureteroscopic urethral realignment was all successful. The catheter was extracted 4-8 weeks after the treatment, and then the urethra was dilated for two years. All patients had normal urination without any surgery complications during the 5-28-month clinical follow-up. ConclusionUrinary tract infections can be prevented effectively under professional and meticulous preoperative treatment. The incidence of urethral stricture can be reduced greatly. The quality of the patients' life can be improved a lot.
ObjectiveTo investigate the effect of medial 1/3 anatomical orientation of the tibial tubercle on the rotational alignment of Gemini MK-Ⅱ tibial components in total knee arthroplasty (TKA). MethodsBetween March 2011 and December 2012, 61 cases (67 knees) of varus knee osteoarthritis underwent Gemini MK-Ⅱ knee arthroplasty, and the clinical data were retrospectively analyzed. There were 12 males and 49 females, with an average age of 67.6 years (range, 50-82 years). The body mass index ranged from 20.9 to 33.7 kg/m2 (mean, 28.2 kg/m2). Unilateral TKA was performed in 55 cases and bilateral TKA in 6 cases. The duration of knee osteoarthritis ranged from 2 to 30 years (mean, 12.1 years). According to radiographic changes, 56 knees were rated as Kellgren-Lawrence grade Ⅲ and 11 knees as grade IV. During TKA, the tibial rotational alignment was determined by medial 1/3 anatomical orientation of the tibial tubercle. The anteroposterior and lateral X-ray films and CT scan were taken to measure the tibial rotational angle (TRA) at pre-and post-operation and to analyze the relative factors for TRA by Pearson correlation analysis. ResultsAll the patients were followed up 18-41 months (mean, 20.5 months). The range of motion (ROM) significantly increased from (98.806±16.969)° preoperatively to (116.806±11.458)° at last follow-up (t=-11.760, P=0.000). The knee society score (KSS) significantly increased from 111.239±20.344 to 160.522±17.872 at last follow-up (t=-27.271, P=0.000). The anatomical tibiofemoral angle (ATFA), posterior condylar angle (PCA), and TRA were all improved after TKA, showing significant differences when compared with preoperative ones (P<0.05). Rotational malalignment was observed in 11 knees (16.42%) before TKA, and in 14 knees (20.90%) at 1 week after TKA, showing no significant difference (χ2=0.443, P=0.506). There were 8 knees (11.94%) of internal rotation (>8°) and 6 knees (8.96%) of external rotation (>8°). The postoperative tibial prosthesis TRA had no correlation with the preoperative ATFA and tibial plateau TRA, the postoperative PCA and ATFA (r=-0.174, P=0.159; r=0.220, P=0.074; r=0.237, P=0.053; r=-0.095, P=0.442). ConclusionIn patients with varus knee osteoarthritis, medial 1/3 anatomical orientation of the tibial tubercle will contribute to the development of tibial rotational malalignment when TKA is performed by using Gemini MK-Ⅱ tibial components.
Objective To investigate the feasibility and effectiveness of high tibial osteotomy (HTO) in treatment of chronic multi-ligament knee injury (MLKI) associated with lower extremity malalignment. Methods A clinical data of 14 patients (14 knees) of chronic MLKI associated with lower extremity malalignment, who were treated with HTO between January 2016 and September 2020, was retrospectively analyzed. There were 10 males and 4 females, with an average age of 30.5 years (range, 22-48 years). The causes of injury included traffic accident in 8 cases, bruising by a heavy object in 3 cases, falling from height in 2 cases, and twisting in 1 case. According to Schenck classification of knee dislocation (KD), there were 4 cases of KD-Ⅰ [2 cases of anterior cruciate ligament (ACL) and posterolateral complex (PLC) injuries and 2 cases of posterior cruciate ligament (PCL) and PLC injuries], 7 cases of KD-Ⅲ (all of ACL, PCL, and PLC injuries), and 3 cases of KD-Ⅳ. The preoperative hip-knee-ankle angle (HKA) was (167.1±4.7)°, and the posterior tibial slope angle (PTSA) was (16.3±2.7)°. The knee joint was severely unstable and the patients could not stand and walk normally. Among them, 5 cases of medial compartment cartilage were severely worn out (3 cases of Kellgren-Lawrence grading Ⅱ, 2 cases of grading Ⅲ) causing pain. After admission, 2 cases of KD-Ⅰ underwent HTO and ligament reconstruction in the first stage, 1 case of KD-Ⅲ and 1 case of KD-Ⅳ underwent HTO in the first stage and ligament reconstruction in the second stage; the remaining 10 patients only underwent HTO. Results All patients were followed up 12-50 months, with an average of 30 months. The incisions healed by first intention after operation, and no complications such as infection and deep vein thrombosis of the lower extremities occurred. At 12 months after operation, knee range of extension was –5°-0° (mean, –1.2°) and range of flexion was 110°-140° (mean, 125.5°). The Lachman test was negative in 11 cases and positive in 3 cases. The posterior drawer test was negative in 9 cases and positive in 5 cases. The 0/30° varus stress test was negative in 10 cases and positive in 4 cases. The 0/30° valgus stress test was negative in 13 cases and positive in 1 case. The visual analogue scale (VAS) score was significantly lower than that before operation (P<0.05), and the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score were all significantly higher than those before operation (P<0.05). The X-ray film reexamination at 12 months after operation showed that the HKA was (178.2±3.8)° and the PTSA was (8.6±2.4)°, which were significantly different from those before operation (P<0.05). All osteotomies achieved bone union, and the healing time was 3-11 months, with an average of 6.8 months. Conclusion For chronic MLKI associated with lower extremity malalignment, HTO can restore normal lower extremity alignment and improve knee joint function, which is a feasible salvage operation.
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.
ObjectiveTo investigate the effect of different electrical stimulation waves on orientation and alignment of adipose derived mesenchymal stem cells (ADSCs).MethodsADSCs were isolated from 5-week-old Sprague Dawley rats (weight, 100-150 g) and cultivated. The cells at passages 3-5 were inoculated to prepare cell climbing slices, subsequently was exposed to direct-current electrical stimulations (ES) at electric field strengths of 1, 2, 3, 4, 5, and 6 V/cm on a homemade electric field bioreactor (groups A1, A2, A3, A4, A5, and A6); at electric field strength of 6 V/cm, at 50% duty cycle, and at frequency of 1 and 2 Hz (groups B1 and B2) of square wave ES; at electric field strength of 6 V/cm, at pulse width of 2 ms, and at frequency of 1 and 2 Hz (groups C1 and C2) of biphasic pulse wave ES; and no ES was given as a control (group D). The changes of cellular morphology affected by applied ES were evaluated by time-lapse micropho-tography via inverted microscope. The cell alignment was evaluated via average orientation factor (OF). The cytoske-leton of electric field treated ADSCs was characterized by rhodamine-phalloidin staining. The cell survival rates were assessed via cell live/dead staining and intracellular calcium activities were detected by calcium ion fluorescent staining.ResultsThe response of ADSCs to ES was related to the direct-current electric field intensity. The higher the direct-current electric field intensity was, the more cells aligned perpendicular to the direction of electric field. At each time point, there was no obvious cell alignment in groups B1, B2 and C1, C2. The average OF of groups A5 and A6 were significantly higher than that of group D (P<0.05), but no significant difference was found between other groups and group D (P>0.05). The cytoskeleton staining showed that the cells of groups A5 and A6 exhibited a compact fascicular structure of cytoskeleton, and tended to be perpendicular to the direction of the electric field vector. The cellular survival rate of groups A4, A5, and A6 were significantly lower than that of group D (P<0.05), but no significant difference was found between other groups and group D (P>0.05). Calcium fluorescence staining showed that the fluorescence intensity of calcium ions in groups A4, A5, and A6 was slightly higher than that in group D, and no significant difference was found between other groups and group D.ConclusionThe direct-current electric field stimulations with physiological electric field strength (5 V/cm and 6 V/cm) can induce the alignment of ADSCs, but no cell alignment is found under conditions of less than 5 V/cm direct-current electric field, square wave, and biphasic pulse wave stimulation. The cellular viability is negatively correlated with the electric field intensity.
Objective To measure the included angle between tibia anatomical axis and anterior cortex, and to define the relative position of them in order to give direction in placement of tibia extra-medullary alignment bar during total knee arthroplasty. Methods A total of 100 healthy volunteers were included (49 left knees and 51 right knees). There were 52 males and 48 females, aged 20-86 years with an average age of 45.2 years (20-35 years in 29 cases, 35-50 years in 32 cases, and over 50 years in 39 cases). The tibiofibular lateral X-ray films were taken to measure the included angle between tibia anatomical axis and anterior cortex with AutoCAD2004 system. The samples were grouped according to gender, age, and side. Results The included angles between tibia anatomical axis and anterior cortex ranged from 3.007 to 3.021° with an average of 3.001°; the angles were (2.965 ± 0.361)° in male and (3.041 ± 0.311)° in female; the angles were (2.996 ± 0.332)° in the left knee and (3.006 ± 0.347)° in the right knee; and the angles were (2.918 ± 0.346)° in 20-35 years age group, (3.060 ± 0.330)° in 35-50 years age group, and (3.014 ± 0.336)° in over 50 years age group. No significant difference was found in the included angle between tibia anatomical axis and anterior cortex between male and female, among different ages, and between left and right knees (P gt; 0.05). Conclusion The included angle between tibia anatomical axis and anterior cortex is about 3°, so tibia extra-medullary alignment bar should be placed at the angle of 3° with anterior cortex during total knee arthroplasty.
Objective To explore the prediction of postoperative coronal lower limb alignment by the tibia fibular angle (TFA) and femoral fibular angle (FFA) after osteotomy in medial open-wedge high tibial osteotomy (MOWHTO). Methods A clinical data of 20 patients with medial compartment osteoarthritis, who were treated with MOWHTO between September 2019 and September 2020, was retrospectively analyzed. Among them, there were 9 males and 11 females; the age ranged from 46 to 69 years, with an average of 56.0 years. The body mass index (BMI) was 21.3- 35.7 kg/m2, with an average of 26.7 kg/m2. Osteoarthritis involved 11 cases of left knee and 9 cases of right knee; the disease duration was 2-6 years, with an average of 3.8 years. According to the Kellgren-Lawrence classification, there were 7 cases of grade Ⅰ, 9 cases of grade Ⅱ, and 4 cases of grade Ⅲ. The angle and height for open-wedge was planned preoperatively by osteotomy master software, and the TFA and FFA were measured by software after simulated osteotomy. The intraoperative angle for open-wedge was adjusted according to TFA and FFA after simulated osteotomy.The lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), mechanical femorotibial angle (mFTA), weight-bearing line (WBL) ratio, TFA, and FFA were measured before operation and at 2 days after operation. The difference (X) between the intraoperative measurement value and the preoperative plan value of TFA/FFA, and the difference (Y) between the postoperative WBL ratio and the target alignment (62.5%) were calculated, and the correlation between the two indicators was analyzed by Pearson’s test. According to the median BMI of patients (25.81 kg/m2), the patients were allocated into high BMI group (>25.81 kg/m2, n=10) and low BMI group (≤25.81 kg/m2, n=10), and the influencing factors of WBL ratio was analyzed by linear regression. Results There was no significant difference between pre- and post-operation in LDFA and JLCA (P>0.05); while there were significant differences between pre- and post-operation in MPTA, mFTA, and WBL ratio (P<0.05). The TFA was (89.5±4.0)° during operation and (87.7±4.7)° after operation, showing significant difference (t=2.991, P=0.008). There was a positive correlation between the difference (X) between the intraoperative measurement value and the preoperative plan value of TFA and the difference (Y) between the postoperative WBL ratio and the target alignment (r=0.595, P=0.006). The FFA was (86.9±4.3)° during operation and (85.7±4.4)° after operation, showing significant difference (t=1.760, P=0.094). There was a positive correlation between the difference (X) between the intraoperative measurement value and the preoperative plan value of FFA and the difference (Y) between the postoperative WBL ratio and the target alignment (r=0.536, P=0.015). After BMI stratification, X was an influential factor of Y in the low BMI group (P<0.05), but X was not an influential factor of Y in the high BMI group (P>0.05). Conclusion Intraoperative FFA and TFA can predict coronal limb alignment after MOWHTO. FFA and TFA can predict more preciselyfor patients with BMI≤25.81 kg/m2.
Objective To explore the mid-term effectiveness of combined knee extensor mechanism realignment with bone anchor for recurrent patella dislocation. Methods Between August 2017 and May 2019, 21 patients with recurrent patella dislocation underwent combined knee extensor mechanism realigament with bone anchor and followed up more than 3 years. There were 8 males and 13 females with an average age of 19.4 years (range, 13-26 years). All 21 patients had a history of recurrent patellar dislocation for 2-5 times (median, 3 times), and the disease duration was 1-16 years (mean, 5 years). The preoperative Lysholm score was 67.5±6.3 and the Kujula score was 64.1±7.0. The defect of meniscus, anterior and posterior cruciate ligaments, and medial and lateral collateral ligaments were excluded by MRI examination; CT examination showed that the tibial tuberosity-trochlear groove distance was 2.05-2.56 cm, with an average of 2.16 cm; X-ray examination showed that lower limb force line was abnormal. The effectiveness were evaluated by Lysholm score and Kujula score before operation and at 3 years after operation, and Insall evaluation standard at 3 years after operation. Results All the incisions healed by first intention, and there was no surgical complication such as lower extremity deep vein thrombosis, incision infection, and nerve injury. All 21 patients were followed up 3.0-3.5 years, with an average of 3.2 years. Anteroposterior and lateral X-ray films of the knee joint at 3 years after operation showed that the position of the patella was normal, and the axial X-ray films of the patella (30°, 60°, 90°) showed that the patellofemoral joint had a good relationship. During the follow-up, there was no anchor drop or fracture, no obvious pseudarthrosis formation, and no epiphyseal injury in the minor patients. The Lysholm score was 91.5±7.1 and the Kujula score was 88.1±7.6 at 3 years after operation, which were significantly improved when compared with those before operation (t=11.57, P=0.00; t=12.78, P=0.00). According to the Insall evaluation criteria, 12 cases were excellent, 4 cases were good, 4 cases were fair, and 1 case was poor, with an excellent and good rate of 76.2%. ConclusionCombined knee extensor mechanism realignment with bone anchor is a simple and reliable way to treat the recurrent patella dislocation, with a satisfactory mid-term effectiveness and less complications; however, its long-term effectiveness needs further follow-up.