Femoral-tibial Angle Research Articles

Automatic Measurement of Lower Limb Angles From Pre‐ and Post‐Operative X‐Ray Images Using a Variant SegNet With Compound Loss Function

ABSTRACTThis work envisages developing an automated computer workflow to locate the landmarks like knee center, tibial plateau, tibial and femoral axis to measure Femur‐Tibia Angle (FTA), Medial Proximal Tibial Angle (MPTA), and Hip Knee Ankle Angle (HKAA) from the pre‐ and post‐operative x‐rays. In this work, we propose a variant of semantic segmentation model (vSegNet) for the segmentation of the knee and tibia gap for extracting important features used in the automated workflow. Since femur tibia gap is a small region as compared to the complete x‐ray image, it poses severe class imbalance issue. Using a combination of the Dice coefficient and Hausdorff distance as a compound loss function, the proposed neural network model shows better segmentation performance as compared to state‐of‐the‐art segmentation models like U‐Net, SegNet (with and without VGG16 pre‐trained weights), VGG16, MobileNetV2, Pretrained DeepLabv3+ (Resnet18 weights), and Pretrained FCN (VGG16 weights) and different loss functions. We subsequently propose computer methods for feature recognition and prediction of landmarks at femur, tibial and knee center, the side of the fibula and, subsequently, the various knee joint angles. An analysis of sensitivity of segmentation accuracy on the accuracy of predicted angles further substantiate the efficacy of the proposed methods. Dice score of U‐Net, Pretrained SegNet, SegNet, VGG16, MobileNetV2, Pretrained DeepLabv3+, Pretrained FCN, vSegNet with cross‐entropy loss function and vSegNet with compound loss function are observed as , , , , , , , and respectively. Using the proposed network vSegNet and the automated workflow, we obtained an Intraclass correlation of 0.999, 0.994, and 0.997 for the FTA, MPTA and HKAA measurements, respectively, with the ground truth. FTA, MPTA, and HKAA measurements using the proposed automatic pipeline positively correlated with the expert's measurement. The proposed vSegNet with compound loss function handles the challenges posed by class imbalance and obtains the best results as compared to other networks and loss functions tested in the work and also in comparison with contemporary works described in literature.

Survival and functional outcomes after hemiarthroplasty in children with proximal tibial osteosarcoma

BackgroundTreatment options for correcting limb-length discrepancy after limb-salvage reconstruction for proximal tibial osteosarcoma in children have several limitations. Therefore, we aimed to evaluate the feasibility, complications, prognosis, and clinical outcomes of reconstruction using hemiarthroplasty after tumor resection in pediatric patients with proximal tibial osteosarcoma.MethodsWe conducted a comprehensive retrospective analysis of the data of pediatric patients with osteosarcoma of the proximal tibia who underwent surgery between December 2008 and November 2018 at our center. We enrolled 49 consecutive patients who underwent hemiarthroplasty. The cruciate ligaments of all patients were reconstructed using special spacers, and the medial and lateral collateral ligaments of the knee and joint capsule were reconstructed using a mesh. Postoperatively, if the unequal length of both lower limbs exceeded 4 cm or knee instability occurred, a second-stage surgery was performed for limb lengthening and replacing the distal femoral prosthesis. We analyzed the oncological prognosis, complications of hemiarthroplasty, postoperative stability, and postoperative function.ResultsThe follow-up period ranged between 11 and 159 months, with a median of 84 (62, 129) months. The overall 5-year survival rate was 83.2%. Thirty-nine patients survived at the end of the follow-up period with 34 prostheses (87.2%). The overall prosthesis survival rate was 87.4% after 5 years, indicating the long-term benefits of the procedure. Limb length was measured in 28 adult patients. The average limb-length discrepancy was 33 ± 15 mm with a median of 33 mm (21, 47); the femur and tibia caused a discrepancy of 8.5 ± 9.9 mm and 24.8 ± 15.5 mm, respectively. The patients had 30–135° of knee motion, with a mean of 82 ± 24°. The femoral tibial angle was greater on the affected side than on the healthy side, with a mean difference of 4.5°±3.6°. The Musculoskeletal Tumor Society (MSTS) score was 25 ± 3. Five patients underwent second-stage distal femoral prosthesis replacement, with mean MSTS scores of 24 ± 2 and 28 ± 1 before and after second-stage surgery, respectively.ConclusionsHemiarthroplasty in children reduces limb-length discrepancy in adulthood by rebuilding cruciate ligaments, lateral collateral ligaments, and the joint capsule, thereby improving knee stability.

A Morphological Study of Distal Femoral Varus Deformity.

Background In the management of medial compartment knee osteoarthritis via around-knee osteotomy (AKO) and total knee arthroplasty (TKA), evaluating the lateral distal femoral angle (LDFA) is crucial. This angle reflects the presence of distal femoral varus deformity. This study aims to explore the relationship between LDFA and lower extremity bone morphology and identify factors contributing to a high LDFA. Methods A retrospective analysis was conducted on 59 patients who underwent AKO or TKA at our hospital. Alignment of the lower extremity was assessed using X-rays, and bone morphology was investigated through computed tomography (CT) employing the ZedKnee® system(LEXI, Tokyo, Japan). Each measured parameter was analyzed. Results Our findings indicate a significant correlation between LDFA and several parameters, including age, femoral tibial angle (FTA), hip knee ankle angle (HKA), percentage of mechanical axis (% MA), femoral bowing angle, femoral tibial joint torsion, and the height of lateral and medial femoral condyles. A multiple-regression analysis determined that the most significant influences on LDFA were the heights of the femoral condyle, age, and HKA. Conclusion LDFA is significantly affected by the heights of the medial and lateral femoral condyles and tends to increase with age, possibly as a result of attrition of the medial femoral condyle. Given its significance, LDFA should be carefully considered as a preoperative indicator in AKO and TKA to guide surgical caution when LDFA is elevated.

Comparison of the effects of sciatic nerve block combined with continuted femoral nerve block or continuted adductor canal block on pain and motor function after total knee arthroplasty

To compare the effect of sciatic nerve block (SNB) combined with continuted femoral nerve block (FNB) or continuted adductor canal block (ACB) on pain and motor function after total knee arthroplasty (TKA). A total of 60 patients with TKA-treated osteoarthritis of the knee who met the selection criteria were enrolled between November 2020 and February 2021 and randomised allocated into the study group (SNB combined with continuted ACB) and the control group (SNB combined with continuted FNB), with 30 cases in each group. There was no significant difference in gender, age, body mass, height, body mass index, preoperative Hospital for Special Surgery (HSS) score, femoral tibial angle, and medial proximal tibial angle between the two groups ( P>0.05). The operation time, the initial time to the ground, the initial walking distance, and the postoperative hospital stay were recorded. At 2, 4, 6, 12, 24, and 48 hours after operation, the numerical rating scale (NRS) score was used to evaluate the rest pain around the knee joint, the quadriceps femoris muscle strength was evaluated by the freehand muscle strength method, and the knee flexion and extension angles were measured. There was no significant difference in the operation time and initial walking distance between the two groups ( P>0.05); the initial time to the ground and postoperative hospital stay of the study group were significantly shorter than those of the control group ( P<0.05). Except for the 48-hour postoperative NRS score of the study group, which was significantly lower than that of the control group ( P<0.05), there was no significant difference in the NRS scores between the two groups at the remaining time points ( P>0.05). The quadriceps femoris muscle strength from 4 to 24 hours postoperatively and the knee extension angle from 2 to 6 hours postoperatively of the study group were significantly better than those of the control group ( P<0.05); the differences in the quadriceps femoris muscle strength and knee extension and flexion angles between the two groups at the remaining time points were not significant ( P>0.05). SNB combined with either continuted ACB or continuted FNB can effectively relieve pain in patients after TKA, and compared with combined continuted FNB, combined continuted ACB has less effect on quadriceps femoris muscle strength, and patients have better recovery of knee flexion and extension mobility.

Morphology and transverse alignment of the patella have no effect on knee gait characteristics in healthy Chinese adults over the age of 40years.

Background: The influence of patella morphology and horizontal alignment on knee joint kinematics and kinetics remains uncertain. This study aimed to assess patella morphology and transverse alignment in relation to knee kinetics and kinematics in individuals without knee conditions. A secondary objective was to investigate the impact of femur and tibia alignment and shape on knee gait within this population. Patients and methods: We conducted a prospective collection of data, including full-leg anteroposterior and skyline X-ray views and three-dimensional gait data, from a cohort comprising 54 healthy individuals aged 40years and older. Our study involved correlation and logistic regression analyses to examine the influence of patella, femur, and tibia morphology and alignment on knee gait. Results: The patellar tilt angle or the patella index did not show any significant relationships with different aspects of gait in the knee joint, such as velocity, angle, or moment (p > 0.05, respectively). Using multivariate logistic regression analysis, we found that the tibiofemoral angle and the Q angle both had a significant effect on the adduction angle (OR = 1.330, 95%CI 1.033-1.711, p = 0.027; OR = 0.475, 95%CI 0.285-0.792, p = 0.04; respectively). The primary variable influencing the knee adduction moment was the tibiofemoral angle (OR = 1.526, 95% CI 1.125-2.069, p = 0.007). Conclusion: In healthy Chinese individuals aged over 40, patella morphology and transverse alignment do not impact knee gait. However, the femoral-tibial angle has a big impact on the knee adduction moment.

Pixee knee+ augmented reality assisted navigation for total knee arthroplasty in an ambulatory surgical center

Total knee arthroplasty (TKA) requires precise alignment for optimal post-operative outcomes and prosthesis longevity. Recently, augmented reality (AR) has emerged as a promising technology in surgical procedures, including TKA. This case series evaluates the feasibility and accuracy of the knee+ augmented reality-assisted navigation (ARAN) system by Pixee Medical in an ambulatory surgical center (ASC) setting. Our study involved 17 consecutive TKA patients performed with the knee+ ARAN system at an ASC from August 2022 to October 2022. Demographic data, including sex, age, ASA score, height, weight, and BMI, were recorded. Postoperative measurements of the mechanical distal femoral angle (MDFA), mechanical distal tibial angle (MDTA), posterior tibial slope (PTS), femoral-tibial angle (FTA), and posterior femoral flexion (PFF) were compared to the ideal intraoperative angles. Outliers were defined as deviations greater than 3° from the planned angles. In this study, 15 out of 17 TKAs utilizing the Pixee knee+ ARAN system were analyzed. All mean post-operative radiographic measurements were within clinically acceptable ranges. The study also found that surgeries using the knee+ system had a slightly longer incision-to-closing time relative to the control group of patients undergoing normal TKA. Our results indicate clinically acceptable accuracy and precision in alignment with the knee+ ARAN system, albeit with a slight increase in surgery duration. This is the first study evaluating the knee+ ARAN system in an ASC setting indicates its suitability for outpatient centers, highlighting its precision, portability, and cost-effectiveness. Larger studies utilizing outcome measures can further assess the system’s advantages and disadvantages.

Analysis of the efficacy of high tibial osteotomy combined with medial meniscus centralization in knee osteoarthritis

To explore the efficacy of high tibial osteotomy （HTO） combined with medial meniscus centralization in knee osteoarthritis. A total of 26 patients who underwent surgery from October 2018 to October 2020 were reviewed. Among them, 14 patients underwent high tibial osteotomy combined with arthroscopic meniscus centralization surgery were centralized group, including 8 males and 6 females, with an average age of （50.2±1.4） years old and follow-up time of （16.8±4.0） months. Twelve patients with high tibial osteotomy were in the control group, including 6 males and 6 females, with an average age of （50.9±1.8） years and follow-up time of （19.0±4.8） months. Operation time, the knee Lysholm score, knee 2000 IKDC score, MRI, femoral tibial angle（FTA）, hip knee ankle angle （HKA）, and intraoperative and postoperative complications were recorded. All the incisions healed without any complication. The operation time in the centralized group was longer than that in the control group[（65.0±2.1）min vs（52.0±2.1）min, P<0.05]. The medial meniscus extrusion reduction value in the centralized group was significantly reduced compared with the control group[（2.8±1.4） mm vs （1.1±2.2） mm, P<0.05]. The FTA, HKA, knee Lyshlom score, and 2000 IKDC score between two groups were no significantly （P>0.05）. Postoperative knee Lyshlom score and knee 2000 IKDC score improved in both groups（P<0.05）. HTO combined with centralization of medial meniscus can improve the reduction of medial meniscus and improve knee function. The medium and long-term curative effect still needs long-term follow-up of more cases.

Early results of high tibial osteotomy versus combined arthroscopic surgery.

To investigate the early effect of high tibial osteotomy (HTO) compared with combined arthroscopic surgery. A retrospective study was conducted on patients who underwent HTO at The First Affiliated Hospital of Shandong First Medical University from January 2018 to January 2022. 138 patients (163 knees) with knee osteoarthritis (KOA) treated with HTO were selected. The medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), femoral tibial angle (FTA), hip-knee-ankle (HKA) angle, weight-bearing line (WBL) ratio of the knee joint, opening gap, opening angle, American Knee Society score (KSS), US Hospital for Special Surgery (HSS) score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were measured to determine the different effects between HTO and HTO combined with arthroscopic by logistic regression analysis. Patients with HTO combined with arthroscopic surgery have improved functional scores as well as imaging perspectives compared to preoperative. By multivariate logistic analysis, it was concluded that arthroscopic surgery and gender are influential factors in the outcome of HTO surgery. The postoperative KSS score was 2.702 times more likely to be classified as excellent in the HTO combined with arthroscopy group than in the HTO group [Exp (β) = 2.702, 95% CI (1.049-6.961), P = 0.039]; the postoperative KSS score was 0.349 times more likely to be classified as excellent in women than in men [Exp (β) = 0.349, 95% CI (0.138-0.883), P = 0.026]. Better results with HTO combined with arthroscopic surgery. HTO combined with arthroscopy is a better choice in the surgical treatment of KOA.

Analysis of lower extremity alignment (LEA) in children with recurrent patellar dislocation by EOS system.

Recurrent patellar dislocation (RPD) greatly affects active young individuals, necessitating the identification of risk factors for a better understanding of its cause. Previous research has connected RPD to lower limb alignment (LEA) abnormalities, such as increased femoral anteversion, tibial external rotation, knee valgus, and flexion. This study aims to use EOS technology to detect RPD-related LEA anomalies, enabling three-dimensional assessment under load conditions. A total of 100 limbs (50 in the RPD group, 50 in the control group) were retrospectively analyzed. In the RPD group, we included limbs with recurrent patellar dislocation, characterized by dislocations occurs at least two times, while healthy limbs served as the control group. We used EOS technology, including 2D and 3D imaging, to measure and compare the following parameters between the two groups in a standing position: Femoral neck shaft angle (NSA), Mechanical femoral tibial angle (MFTA), Mechanical lateral distal femoral angle (mLDFA), Medial proximal tibial angle (MPTA), Anatomical femoral anteversion (AFA), External tibial torsion (ETT), and Femorotibial rotation (FTR). The significant differences between the two groups were shown in NSA 3/2D, MFTA 3/2D, mLDFA 3/2D, MPTA 3D, AFA, FTR. No significant difference was shown in MPTA 2D, ETT between the RPD group and the control group. Further binary logistic regression analysis. Further binary logistic regression analysis was conducted on the risk factors affecting RPD mentioned above. and found four risk factors for binary logistic regression analysis: mLDFA (3D), AFA, NSA(3D), and FTR. EOS imaging identified abnormal LEA parameters, including NSA, MFTA, mLDFA, MPTA, AFA, and FTR, as risk factors for RPD. Children with these risk factors should receive moderate knee joint protection.

Effect of open-wedge high tibial osteotomy and lateral patellofemoral retinacular release on patellar position: an X-ray imaging-based comparative study.

Open-wedge high tibial osteotomy (OWHTO) may cause adverse changes in the mechanical environment of the patellofemoral joint. For patients with lateral patellar compression syndrome or patellofemoral arthritis, intraoperative management is still challenging. The effect of lateral retinacular release (LRR) on patellofemoral joint mechanics after OWHTO remains unclear. Our study aimed to evaluate the effect of OWHTO and LRR on the patellar position based on lateral and axial radiographs of the knee joint. The study comprised 101 knees (OWHTO group) undergoing OWHTO alone and 30 knees (LRR group) undergoing OWHTO and concomitant LRR. The following radiological parameters were statistically analyzed preoperatively and postoperatively: femoral tibial angle (FTA), medial proximal tibial angle (MPTA), weight-bearing line percentage (WBLP), Caton-Deschamps index (CDI), Insall-Salvati index (ISI), lateral patellar tilt angle (LPTA), and lateral patellar shift (LPS). The follow-up duration ranged from 6 to 38 months, with a mean of 13.51±6.84 months in the OWHTO group and 12.47±7.81 months in the LRR group. The Kellgren-Lawrence (KL) grading system was used to evaluate changes in patellofemoral osteoarthritis (OA). Regarding the patellar height, preliminary analysis demonstrated a statistically significant decrease in the CDI and ISI in both groups (P<0.05). However, there was no significant difference in changes in CDI or ISI between the groups (P>0.05). In the OWHTO group, although there was a significant increase in the LPTA (P=0.033), the postoperative decrease in the LPS was not significant (P=0.981). In the LRR group, both the LPTA and LPS significantly decreased postoperatively (P=0.000). The mean changes in LPS were 0.03 mm in the OWHTO group and 1.44 mm in the LRR group, indicating a significant change in LPS (P=0.000). However, there was no significant difference in changes in LPTA between the groups, which was contrary to our expectations. Imaging showed no change in patellofemoral OA in the LRR group and progressive changes (from KL grade I to II) in patellofemoral OA in 2 (1.98%) patients in the OWHTO group. OWHTO can cause a significant decrease in patellar height and an increase in lateral tilt. LRR can significantly improve the lateral tilt and shift of the patella. The concomitant arthroscopic LRR should be considered for the treatment of patients with lateral patellar compression syndrome or patellofemoral arthritis.

Correlation analysis between imaging classification of varus knee osteoarthritis and axis angle of tibiofemoral and patellofemoral joints

To explore correlation between imaging classification of knee osteoarthritis (KOA) and axis angle of tibiofemoral and patellofemoral joints. A retrospective analysis of 739 middle-aged and elderly patients with KOA (1 026 knee joints) who underwent vertical X-ray examination of both lower limbs and lateral knee joints from September 2018 to December 2020. Among them, 63 patients with K-L 0 grade (95 knee joints), 100 patients with K-L 1 grade (130 knee joints), 161 patients with K-L 2 grade (226 knee joints), 187 patients with K-L 3 grade (256 knee joints), and 228 patients of K-L 4 grade (319 knee joints). According to relative position of knee joint center and line between hip joint center and ankle joint center, the affected knee was divided into varus group(844 knees joints) and valgus group (182 knees joints). According to Install-Salvati method, the affected knee was divided into three groups, such as high patella (patella height>1.2 mm, 347 knees joints), median patella (patella height ranged from 0.8 to 1.2 mm, 561 knees joints), and low patella (patella height<0.8 mm, 118 knees joints). Lower femur angle, upper tibia angle, femoral neck shaft angle, femoral tibial angle, joint gap angle, hip-knee-ankle angle, patella-femoral angle and patella height among different groups were observed and compared. (1) In varus KOA group, there were statistical differnces in hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, joint space angle, and femoral neck shaft angle of patients with different K-L grades (P<0.05). Hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, joint space angle and K-L grade were significantly positively correlated at 0.01(P<0.05);femoral neck shaft angle and K-L grade showed negative correlation at 0.01(P<0.05). (2) In valgus KOA group, hip-knee-ankle angle, there were statistical differences in tibiofemoral angle, inferior femoral angle, superior tibial angle, joint space angle, and femoral neck shaft angle of patients with different K-L grades(P<0.05). Hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, and femoral neck shaft angle showed negative correlation with K-L grades at level of 0.01 (P<0.05);joint gap angle and K-L grades showed significantly positive correlation at level of 0.01(P<0.05). (3) In high patella group, there were statistically differences in patellar height and patellar femoral angle of different K-L grades(P<0.05);there were no statistical difference in patella height and patellar femoral angle of different K-L grades in median patella group. There was no significant difference in patella heightin low patella group with different K-L grades(P>0.05), and there was statistical difference in patellofemoral angle(P<0.05). Patellar height and patella-femoral angle of high patella group were significantly positively correlated with K-L grades at the level of 0.01 (P<0.05);patella height and patella-femoral angle were not correlated with K-L grades in median patella group(P>0.05). There was no correlation between height of patella and K-L grade in low patella group (P>0.05). There was significant negative correlation between patella-femoral angle and K-L grade at level of 0.05 (P<0.05). Inferior femoral angle, tibiofemoral angle, joint gap angle, hip-knee-ankle angle, femoral neck shaft angle and high patella are related to K-L classification of varus KOA, which could be used for early diagnosis and provide objective data for efficacy analysis of conservative treatment.

Early surgical outcomes and influencing factors of high tibial osteotomy.

To investigate the influencing factors of functional recovery after high tibial osteotomy (HTO). A retrospective research was carried on 98 patients who underwent HTO between January 2018 and December 2020. In each case, the medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), femoral tibial angle (FTA), hip-knee-ankle (HKA), weight bearing line (WBL) ratio of the knee joint, opening gap, opening angle, American knee society knee score (KSS), US Hospital for Special Surgery (HSS) score, Lysholm score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were measured to determine postoperative function and influential factors of pain through logistic regression analysis. The follow-up time was between 18 and 42 months after operation with an average of 27.66 ± 12.9 per month. Overall functional scores were significantly improved. The influencing factors that may affect the postoperative effect of HTO include age and preoperative WBL ratio of the knee joint (WBL%). After incorporating these two factors into the multivariate logistic regression analysis, for every 1 unit increase in the preoperative WBL%, the probability of postoperative HSS being superior is 1.06 times higher than before [Exp(β): 1.062, 95% CI: 1.01-1.1, p = 0.018]. For every year increase in age, the probability of an excellent HSS score after surgery was 0.84 times higher than that before surgery [Exp(β): 0.843, 95% CI: 0.718-0.989, p = 0.036]. Preoperative WBL% ≥ 14.37 was 17.4 times more likely to be rated as excellent postoperative HSS than that <14.37 [Exp(β): 17.406, 95% CI: 1.621-186.927, p = 0.018]. The postoperative functional scores of the patients significantly improved. Patients with preoperative WBL% ≥ 14.37% had better function after surgery.

Pie-Crusting Technique of Medial Collateral Ligament for Total Knee Arthroplasty in Varus Deformity: A Systematic Review.

We aimed to better understand the outcomes/complications of pie-crusting technique using blade knife during total knee arthroplasty (TKA) in patients with knee genu varum deformity. A systematic search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. English and Persian language articles were considered on the use of pie-crusting technique during TKA in patients with knee genu varum/varus deformity using related keywords and Medical Subject Headings terms with reported postoperative complications and outcomes. Primary search resulted in 81 studies of them 9 included in our study (ages ranged: 19 years to 62 years). No perioperative complications and/or any significant differences between pie-crusting and control group were observed. Except for two studies that found no significant positive effect for the use of pie-crusting, other studies found pie-crusting a useful and promising technique. Four studies found significant improvement in pie-crusting group compared to control in terms of functional Knee Society Score (KSS), range of motion (ROM), medial gap, and the knee-specific KKS. Three records found no significant differences in terms of functional KSS, ROM; however, they reported fewer use of constrained inserts or a reasonable correction of femoral tibial angle. No serious complications were reported. Due to the inconsistency of the results on the efficiency and outcomes of pie-crusting, we cannot make a firm conclusion and more high-quality studies are needed in this regard. However, this method can be considered as a safe method which depends on the skill of surgeon.

Coronal Laxity at Flexion is Larger After Posterior-Stabilized Total Knee Arthroplasty Than With Cruciate-Retaining Procedures

BackgroundIt is unclear whether coronal stability differs between cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA). The purpose of this study was to compare coronal laxity, radiological, and clinical outcomes between CR-TKA and PS-TKA. MethodsSeventy five CR-TKAs and 72 PS-TKAs with a minimum 2-year follow-up were retrospectively evaluated. Coronal laxity was assessed at knee extension and 80° of flexion on varus and valgus stress radiographs. Radiological evaluation included femoral-tibial angle, hip-knee-ankle angle, and positions of femoral and tibial components. Clinical evaluation included the modified Hospital for Special Surgery score, the Western Ontario and McMaster Universities Osteoarthritis index, and range of motion. ResultsPS-TKA resulted in significantly larger varus, valgus, and total laxities at 80° flexion (P = .034, .031, and 0.001, respectively) compared with CR-TKA, while no significant difference was found at extension (P = .513, .964, and .658, respectively). No statistical difference was found in radiological and clinical outcomes between CR-TKA and PS-TKA, but the functional scores were slightly better in CR-TKA. There were adverse correlations between varus laxity at flexion and the Western Ontario and McMaster Universities Osteoarthritis index, the modified Hospital for Special Surgery score, and range of motion (r = 0.933, −0.229, −0.472, respectively). ConclusionCoronal laxity at 80° of flexion was larger after PS-TKA than CR-TKA. In addition, clinical outcomes were adversely affected by the larger varus laxity at flexion. Care should be taken to maintain the coronal stability, especially at flexion, during surgery to obtain better patient-reported outcomes. Level of evidenceLevel III.

Using musculoskeletal modelling to estimate knee joint loading pre and post high tibial osteotomy

BackgroundBoth medial knee osteoarthritis and associated varus alignment have been proposed to alter knee joint loading and consequently overloading the medial compartment. Individuals with knee osteoarthritis and varus deformity are candidates for coronal plane corrective surgery, high tibial osteotomy. This study evaluated knee loading and contact location for a control group, a pre-surgery cohort and the same cohort 12 months post-surgery using a musculoskeletal modelling approach. MethodsJoint kinematics during gait were measured in 30 knee osteoarthritis patients, before and after high tibial osteotomy, and 28 healthy adults. Using a musculoskeletal model that incorporated patient-specific mechanical tibial femoral angle, the resulting muscle, ligament, and contact forces were calculated and the medial - lateral condyle load distribution was analysed. FindingsSurgery changed medial compartment contact force throughout stance relative to pre-surgery. This reduction in medial compartment contact force pre- vs post-HTO is observed despite a significant increase in post-surgery walking speed compared to pre-HTO, where increased speed is typically associated with increased joint loading. InterpretationThis study has estimated the effects of high tibial osteotomy on knee loading using a generic model that incorporates a detailed knee model to better understand tibiofemoral contact loading. The findings support the aim of surgery to unload the medial knee compartment and lateralise joint contact forces.

Clinical efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box in open-wedge high tibial osteotomy

BackgroundThe clinical outcomes of open-wedge high tibial osteotomy (OWHTO) for medial knee osteoarthritis primarily depend on the corrective precision. The present study aimed to determine the efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box.MethodsThis prospective and randomized trial included 71 patients randomly divided into laser (n = 36) and traditional groups (n = 35). In the laser group, the hip centre, knee (Fujisawa point), and ankle centre were located preoperatively using the surgical instrument box lid. The leg was aligned with an ordinary laser pen. In the traditional group, the lower limb alignment was corrected by a metal cable. Radiation exposure, operative time, and rate of outliers (lower limb force line does not pass through 62–66% of the lateral tibial plateau) were evaluated. The visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were recorded. After 24 months, the femoral tibial angle (FTA), medial proximal tibial angle (MPTA), and posterior slope angle (PSA), were recorded. The Kaplan-Meier method was used to evaluate the survival time of affected knees, and postoperative complications were recorded.ResultsThe radiation exposure, operative time and rate of outliers were lower in the laser correction group (P < 0.05). Six months postoperatively, the VAS and WOMAC scores were significantly improved in both groups (P < 0.001). At 24 months, the FTA, MPTA, and PSA were corrected in both groups (P < 0.001). There were no differences in the postoperative knee survival time from OWHTO to knee arthroplasty between the groups or postoperative complications (P = 0.53; P = 0.61).ConclusionsLaser correction technology can effectively reduce radiation exposure, the operative time, and the rate of outliers (trial identification number (retrospectively registered): ChiCTR2200060480; date of register: 03/06/2022).

Effect of open wedge tibial high osteotomy on patella position and joint function

To investigate the effect of open wedge tibial high osteotomy on patella position, anterior knee pain and joint function. From June 2016 to June 2021, 109 patients (111 knees) with medial knee osteoarthropathy treated by open wedge tibial high osteotomy were included according to the inclusion and exclusion criteria, including 41 males and 68 females;the age ranged from 38 to 78 years old with an average of(57.98±7.07) years;the course of disease ranged from 1 to 36 months with an average of (8.58±6.91) months. The femoral tibial angle(FTA), medial proximal tibial angle(MPTA), weight bearing line(WBL) percentage, Caton Deschamps index (CD index), lateral patella tilt angle (LPTA) and lateral patella shift (LPS) were observed and compared before and after operation. Lysholm score was used to evaluate the knee function, visual analogue scale(VAS) was used to evaluate the degree of anterior knee pain, and Kellgren Lawrence(K-L) grading system was used to evaluate the progress of patellofemoral osteoarthritis. All patients were followed up for 6 to 38 months with an average of (12.41±2.40) months. The preoperative FTA, MPTA, WBL percentage, CD index, and LPTA were significantly different from those at the last follow-up(P<0.05). There was no significant difference between before and after LPS operation(P=0.78). Lysholm score increased from (58.79±7.90) scores to (76.05±7.36) scores (P<0.05). The VAS of anterior knee pain decreased from (3.28±1.95) scores to(1.07±1.75) scores(P<0.05). Knee patellofemoral osteoarthritis showed progressive changes, but there was no significant difference in K-L grading before and after operation (P>0.05). After open wedge tibial high osteotomy, the position of patella is lowered and the patella is tilted outward, but the knee function and anterior knee pain are significantly improved. Adverse changes in patella position caused by open wedge tibial high osteotomy may not affect clinical outcomes.

Alignment analysis of Brainlab knee 3 navigation-guided total knee arthroplasty using the adjusted mechanical method.

With the application of navigation technology in Total Knee Arthroplasty (TKA), TKA procedures have become various. Studies have shown that navigation can improve the alignment of patients' lower limbs. To verify this conclusion, we collected the clinical data from patients who underwent Brainlab knee 3 navigation-guided TKA. Brainlab knee 3 is a completely new software that takes a different approach to address the current challenges of navigated TKA. During the procedure, we applied the Adjusted Mechanical Alignment (AMA) principle and took soft tissue balance as a priority. We aim to explore the patients' lower limb alignment changes who underwent the Brainlab knee 3 navigation-guided TKA using the AMA method. Fifty consecutive patients who underwent total knee arthroplasty using the Brainlab knee3 knee navigation system (Smith&Nephew) from January to August 2021 by the same doctor (Yunsu Chen) in the Department of Joint Surgery of the Shanghai Sixth People's Hospital were included. Hip-Knee-Ankle Angle (HKAA), anatomic Femur Tibia Angle (FTA), Lateral Distal Femoral Angle (LDFA), and medial proximal tibia angle (MPTA) were measured on preoperative and postoperative full-length lower-limbs x-ray films or weight-bearing anterior and lateral knee radiographs for observational and descriptive study. The preoperative and postoperative knee alignment changes were analyzed through paired t-test or nonparametric Wilcoxon test using SPSS 25.0 software. Pre-operative and post-operative HKAA both obeyed normal distribution. The mean preoperative HKAA was 169.8° (154.9-178.7°) with a standard deviation of 5.41; the postoperative HKAA was 175.7° (168.4-180.0°) with a standard deviation of 2.81. Using the two-sample paired t-test to analyze, the result showed P = 0.000 < 0.05; a statistically significant difference exists. The preoperative and postoperative FTA obeyed normal distribution as well. The mean preoperative FTA was 174.7° (163.4-179.9°) with a standard deviation of 3.90; postoperative 175.6° (167.0-179.9°) with a standard deviation of 2.77. Using the two-sample paired t-test to analyze, the result showed P = 0.140 > 0.05, the difference was not statistically significant. The preoperative LDFA was normally distributed, while postoperative LDFA was not. The mean preoperative LDFA was 90.7° (83.5-99.6°) with a standard deviation of 3.83; the median of postoperative LDFA was 91.6° (86.0-103.2°) with an interquartile range of 2.93. Using the two-sample paired Wilcoxon test, the result showed P = 0.052 > 0.05; the difference was not statistically significant. Preoperative MPTA obeyed normal distribution, while postoperative MPTA did not. The mean preoperative MPTA was 83.5° (72.7-92.9°), with a standard deviation of 3.66; the median of postoperative MPTA was 89.3° (84.6-95.6°), with an interquartile range of 1.45. Using the two-sample paired Wilcoxon test, the result shows P = 0.000 < 0.05; a statistically significant difference exists. In our study, AMA alignment was applied in Brainlab Knee3 computer navigation-assisted total knee arthroplasty. The femoral and tibial osteotomy angles were minimally adjusted according to soft tissue situations to reduce soft tissue release. We found AMA alignment provides good control of knee alignment in the coronal plane of the lower limbs, which is a reliable technique.

Proximal fibular osteotomy versus high tibial osteotomy for treating knee osteoarthritis: a systematic review and meta-analysis

BackgroundKnee osteoarthritis (KOA) with varus alignment and medial space stenosis is a common degenerative disorder in the elderly. To reallocate the force bearing from the medial to the lateral compartment, the anti-varus osteotomy, including high tibial osteotomy (HTO) and proximal fibular osteotomy (PFO), corrects the mechanical lines of lower extremities using surgical methods, which alleviates the abrasion of medial cartilage and relieves pain. PFO is based on the “non-uniform settlement” theory. It is to cut small section of the proximal fibula, i.e., below the fibula head, which breaks the fibula and weakens its support for the lateral of the tibial plateau, lastly reduces the gap on the lateral side of the knee joint and offsets the knee varus deformity caused by weight bearing. We conducted this systematic review and meta-analysis to compare the clinical outcomes of PFO versus HTO intervention.MethodsTwenty-three studies were acquired from PubMed, Embase, CNKI (China National Knowledge Infrastructure), Wanfang Database and Cochrane Library. The data were extracted by two of the coauthors independently and were analyzed by RevMan5.3. Mean differences (MDs), odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Cochrane Collaboration’s Risk of Bias Tool and Newcastle–Ottawa Scale were used to assess risk of bias.ResultsTwenty-three studies including 14 randomized controlled trials and 9 observational studies were assessed. The methodological quality of the trials ranged from low to high. The pooled results of the mean operation time (MD = − 38.75, 95% CI = − 45.66 to − 31.85, P < 0.00001), intraoperative bleeding (std. MD = − 4.12, 95% CI = − 5 to − 3.24, P < 0.00001), length of hospital stay (MD = − 3.77, 95% CI = − 4.98 to − 2.56, P < 0.00001) and postoperative complications (OR = 0.66, 95% CI = 0.37–1.18, P = 0.16) showed that the differences were statistically significant between the two interventions. The postoperative differences of visual analogue score (VAS) (MD = 0.15 95% CI = − 0.39 to 0.69, P = 0.58), hospital for Special Surgery knee score (HSS) (MD = − 2.68, 95% CI = − 6.30 to 0.94, P = 0.15), American knee society (AKS) score (MD = 0.04, 95% CI = − 0.69 to 0.77, P = 0.91), western Ontario and McMaster university of orthopedic index (WOMAC) (MD = 8.09, 95% CI = 2.06–14.13, P = 0.009) and femur–tibia angle (FTA) (MD = − 0.03, 95% CI = − 5.39 to 5.33, P = 0.99) were not statistically significant. Sensitivity analysis proved the stability of the pooled results and the publication bias was not apparent.ConclusionsPFO and HTO have the same short-term efficacy in the treatment of KOA, but PFO can reduce the operation time, intraoperative bleeding, hospital stay and postoperative complications, which has certain advantages. Clinically, for patients with many complications and poor surgical tolerance, PFO can be preferred.

Machine Learning Algorithm to Predict Worsening of Flexion Range of Motion After Total Knee Arthroplasty

BackgroundPredicting the worsening of flexion range of motion (ROM) during the course post-total knee arthroplasty (TKA) is clinically meaningful. This study aimed to create a model that could predict the worsening of knee flexion ROM during the TKA course using a machine learning algorithm and to examine its accuracy and predictive variables. MethodsAltogether, 344 patients (508 knees) who underwent TKA were enrolled. Knee flexion ROM worsening was defined as ROM decrease of ≥10° between 1 month and 6 months post-TKA. A predictive model for worsening was investigated using 31 variables obtained retrospectively. 5 data sets were created using stratified 5-fold cross-validation. Total data (n = 508) were randomly divided into training (n = 407) and test (n = 101) data. On each data set, 5 machine learning algorithms (logistic regression, support vector machine, multilayer perceptron, decision tree, and random forest) were applied; the optimal algorithm was decided. Then, variables extracted using recursive feature elimination were combined; by combination, random forest models were created and compared. The accuracy rate and area under the curve were calculated. Finally, the importance of variables was calculated for the most accurate model. ResultsThe knees were classified into the worsening (n = 124) and nonworsening (n = 384) groups. The random forest model with 3 variables had the highest accuracy rate, 0.86 (area under the curve, 0.72). These variables (importance) were joint-line change (1.000), postoperative femoral-tibial angle (0.887), and hemoglobin A1c (0.468). ConclusionsThe random forest model with the above variables is useful for predicting the worsening of knee flexion ROM during the course post-TKA.