Correlation analysis between the coronal and sagittal axis angles of both knees and lumbar lordosis in middle-aged and elderly patients with knee osteoarthritis.

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.

Objectives:Knee alignment following total knee arthroplasty (TKA) may be the most important factor determining the long-term survival of the prosthesis. Despite proper alignment of implants being strongly associated with greater stability and a lower rate of loosening, literature still finds conflicting results regarding the influence of TKA alignment in patients clinical scores. The present study sought to address what is the optimal postoperative TKA alignment.Methods:We retrospectively selected 100 consecutive primary knee replacements performed for primary knee osteoarthritis. Pre-operative full length weight bearing x-rays were used to evaluate native knee anatomic alignment, as well as proximal tibial and distal femoral coronal alignment. Pos-operative full length weight bearing x-rays were also used to evaluate TKA alignment, tibial and femoral components coronal alignment, tibial position, tibial slope and femoral flexion angle. Extension anteroposterior (AP) and profile at 30º of flexion x-rays were used. Functional assessment was conducted including the VAS, the Oxford Knee and the Kujala scores, as well as range of motion (ROM).Results:Regarding ROM, only 8 patients didn’t presented full range of motion. Regarding the native knee, the average anatomical angle was 174 ± 4º. The average femoral distal coronal angle was 88±4º and the average tibial proximal coronal angle was 89±6º. The average post-operative angles were: 175±3º for the TKA tibia-femoral coronal angle, 88±6º for the coronal femoral angle and 89±3º for the coronal tibial angle. Regarding tibial tray position, when referring to the medial cortex of the proximal tibia, our sample had a tray in average 1±1mm more lateral than the medial cortex, with the worst positioned tibial components being 3,2mm medial or lateral to the medial cortex. When considering the proximal tibia lateral cortex, our patients had in average a tibial tray 1±2mm more medial than the lateral cortex, with the worst positioned tibial components being 4,2mm medial or 2,2mm lateral to the lateral cortex. Regarding the TKA sagittal alignment, the average TKA tibial slope was of 3±4º, and the average femoral flexion angle was 10±3º. Gender, IMC or age didn’t seem to influence TKA clinical results, either regarding pain (VAS) or function (Kujala or Osxford Scores).Comparing patients with post-operative alignment within of 5º of the native knee anatomical alignment, with patients with greater differences, no significant differences were obtained regarding pain or function.Also comparing patients with pos-operative coronal femoral or tibial angle within 85-95º, with patients with greater differences, no significant differences were reached regarding clinical outcomes. Besides that, tibial tray coronal position also didn’t seem to influence patient results.In regard to sagittal alignment, neither the femoral flexion angle or the tibial slope showed and correlation to post-operative outcomes. Regarding TKA size, the tibial tray or polytene size didn’t seem to influence clinical outcomes, however the femoral component size showed correlation with the functional scores, with smaller femoral sizes associated with greater Oxford scores (p=0,0029).Conclusion:Most patients of our sample seem to have well aligned TKA, with an difference of only 1º between the native knee anatomic angle and the TKA alignment. Regarding tibial tray position, most surgeons opted for a tibial tray smaller than the tibial plateau, however these differences were of 1 millimeter medially and laterally, which probably is not clinically significant. The tibial slope is also within the desired values of 0-7º. We verified that most errors in tibial tray regard positioning it more medially than laterally, however we can assume that the tibial tray is, in most patients, correctly sized and positioned. Regarding femoral sagittal alignment, our sample showed a greater femoral flexion than previously described, however the clinical relevance of this measurement is sill controverse. Despite some papers describing an association between greater femoral flexion angle and patellofemoral instability, in our sample this angle didn’t seem to influence the Kujala score. No differences in pain or functional results were obtain in regard to TKA alignment, however this can be explained by the fact that most patients presented well aligned TKAs.

The aim of this study was to evaluate the inter- and intra-observer reliability of plain digital radiographs for assessing normal feline femoral and tibial joint reference angles in the sagittal and frontal planes. This was a cadaveric radiographic anatomical study. that involved 20 short-haired domestic adult cats. Sagittal and frontal plane tibial and femoral joint angles of 40 limbs were measured twice by three observers with different levels of experience. Inter- and intraobserver reliability was determined by the intra-class correlation coefficient (ICC). An ICC > 0.75 was considered high correlation, 0.74 > ICC > 0.60 good correlation, 0.59 > ICC > 0.4 fair correlation and an ICC < 0.40 poor correlation. Mean ± standard deviation angles were anatomic lateral proximal femoral angle (aLPFA) 110.6 ± 3.6; anatomic lateral distal femoral angle (aLDFA) 91.9 ± 2.1; mechanical lateral proximal femoral angle; mLPFA (mLPFA) 107.3 ± 3.6; mechanical lateral distal femoral angle (mLDFA) 95.5 ± 1.7; femoral neck anteversion (FNA) 121.9 ± 4.1; anatomical caudal proximal femoral angle (aCPFA) 156.1 ± 3.9; anatomical caudal distal femoral angle (aCDFA) 101.4 ± 1.4; mechanical medial proximal tibial angle (mMPTA) 93.5 ± 1.2; mechanical medial distal tibial angle (mMDTA) 100.5 ± 2.3; mechanical cranial proximal tibial angle (mCrPTA) 113.1 ± 3.2; tibial plateau angle (TPA) 23.1 ± 3.2; mechanical cranial proximal tibial angle (mCrDTA) 86.7 ± 3.1.The intra-observer ICC indicated high correlation for 70% or more of the measurements. The inter-observer agreement among observers was high. These results show that the radiographic method for measuring femoral and tibial joint angles was good or high, except for FNA and mCrDTA. This study provides some radiographic anatomical and mechanical joint angles of the femurs and tibias of normal domestic short-haired cats. We found good reliability for both intra- and interobserver measurements.

To investigate the effect of lateral retinacular release on the clinical outcomes after total knee arthroplasty (TKA) without resurfacing of the patella. A prospective randomized controlled study was performed on 132 patients with unilateral degenerative knee arthritis undergoing TKA bewteen October 2012 and October 2014, who met the selection criteria. During TKA, lateral retinacular release was used in 66 cases (trial group) and was not used in 66 cases (control group). Two patients were excluded from the study due to missing the follow-up in trial group. Four patients were excluded from the study due to lateral retinacular release in control group. Finally, 64 patients and 62 patients were included in the trial group and in the control group. There was no significant difference in gender, age, body mass index, side, disease duration, preoperative patellar morphology, grading of patellofemoral arthritis, grade of patellar cartilage degeneration, patellar malposition, patellar maltracking, patellar score, and Knee Society Score (KSS) between 2 groups ( P>0.05). The operation time, postoperative drainage volume, hospitalization time, postoperative complications, and patient satisfaction were recorded. Postoperative anterior knee pain was assessed by visual analogue scale (VAS), and the knee joint function was evaluated by KSS score and patellar score. The femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle were measured on the X-ray film for postoperative prosthetic alignment. The postoperative patellar tracking and patellar position, as well as the presence of osteolysis, prosthesis loosening, patellar fracture and patellar necrosis were observed. All patients were followed up for 24 months. There was no significant difference in operation time, postoperative drainage volume, hospitalization time, and patient satisfaction between 2 groups ( P>0.05). The incidence of anterior knee pain in the trial group was better than that in the control group ( P=0.033). KSS score and patellar score were significantly improved in both groups at 24 months after operation when compared with preoperative scores ( P<0.05), but no significant difference was found between 2 groups ( P>0.05). Complications included hematoma (2 cases in the trial group, and 1 case in the control group), mild wound dehiscence (2 cases in each group respectively), skin-edge necrosis (1 case in the trial group), and superficial wound infection (1 case in each group respectively), which were cured by conservative treatment. No patellar necrosis, patella fracture, or knee lateral pain occurred in 2 groups. There was no significant difference in complication rate between groups ( P=0.392). Satisfactory implant alignment was observed in both groups during follow-up. There was no significant difference in femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle between 2 groups ( P>0.05). No radiolucent line at the bone-implant interface was seen around the tibial components and femoral components in both groups. The patellar maltracking was observed in 3 patients of the trial group and 5 patients of the control group, showing no significant difference ( P=0.488). However, the incidence of patellar malposition in the trial group (18.8%) was significantly lower than that in the control group (35.5%) ( χ2=0.173, P=0.034). Lateral retinacular release during primary TKA without resurfacing of the patella can reduce postoperative knee pain without increasing complications.

Purpose: The aim of this study was to evaluate the influence of surgical experience of an orthopaedic surgeon on femoral and tibial tunnel placement during anterior cruciate ligament (ACL) reconstruction, and the effect of tunnel angle on patient self-report outcomes. Methods: We retrospectively reviewed 115 consecutive ACL reconstruction surgeries by a single fellowship-trained orthopaedic surgeon over his first 5 years in practice. 70 patients with hamstring (HS) and 44 patients with bone-patellar tendon-bone (BTB) autografts were included, all epiphyseal approaches, graft hybrids or allografts were excluded. Posterior distal femoral angle (PDFA), femoral and tibial tunnel angulation were measured on AP and lateral radiographs by 2 independent raters with high inter-rater reliability (ICC &gt;0.8 for all measures). Tunnel angulation was compared to recently reported ideal femoral angle of 33.5°±1.8 or ideal tibial angle of 62.5°±5 (Luthringer et al, 2016). Complications and self-report outcomes - pediIKDC, Tegner-Lysholm and KOOSChild - were recorded, as well as demographics, injury and surgery characteristics (e.g. concurrent meniscal repairs, chondroplasty, tourniquet time). Average follow-up was 1.14 years. Continuous variables were analyzed using unpaired t-test, Wilcoxon rank sum test and Spearman correlation. Categorical variables were analyzed using Fisher’s exact test. Results: ACL reconstruction was performed at an average age of 16.7 years (range, 11.8 to 20.4 years), 59% males. Figure 1 shows tunnel angles over case groups of N=15. For HS autografts, femoral tunnel angle and tibial tunnel angle improved toward the ideal angle after 15 cases (ANOVA, p=0.020 and p=0.031, respectively). For BTB autografts, femoral tunnel angle and tibial tunnel angle did not demonstrate a significant change over cases (Figure 1). The tibial tunnel angle in HS cases showed a negative weak correlation with the selected outcome scores at 6 months and 1 year after ACL reconstruction, whereas the tibial tunnel angle in BTB cases showed a weak positive correlation with KOOSChild pain scores 6 months after initial surgery (Table 1). For either graft type, femoral tunnel angle was not correlated with any outcome measure. Overall, self-report outcome scores were similar between patients with ideal and non-ideal tunnel angles (data not shown). Of the 70 patients with HS autografts, 5 (7%) required a secondary surgery: 2 revisions for graft tear, 1 revision for a non-functional graft, 1 for arthrofibrosis and 1 for a prominent tibial screw. PDFA, femoral and tibial tunnel angle were similar between patients needing secondary surgery and those who did not (Table 2). Patients needing revision surgery had significantly lower Tegner-Lysholm and KOOSChild Pain scores at 6 months after the initial ACL reconstruction. Of the 44 BTB patients, 3 (6.8%) had complications: 2 patients developed arthrofibrosis and subsequently underwent surgery, and 1 patient experienced neuropathy. In these patients, the PDFA was significantly higher, the femoral tunnel angle significantly lower and tibial tunnel angle similar compared to those without a complication (Table 2). Demographic factors, injury and surgical parameters (concurrent meniscal repairs, chondroplasty, tourniquet time, aso) were similar between HS patients with or without additional surgery and between BTB patients with and without complications. Conclusion/Significance: Femoral and tibial tunnel angle improved towards the reported ideal angle after 15 cases for HS autografts. PDFA, femoral and tibial tunnel angle were not associated with surgical complications in HS patients. For BTB autografts, no significant changes were seen in tunnel placement with surgical experience. Patients experiencing complications after BTB autografts had a low femoral tunnel angle and high PDFA. Overall, tibial tunnel angle, but not femoral tunnel angle, correlated with outcome scores of patients with BTB and HS autografts. [Figure: see text][Table: see text][Table: see text]

ObjectiveTo describe a new alignment technique of adjusted restricted kinematic alignment (arKA) for the treatment of severe varus deformity in total knee arthroplasty.MethodsThree female patients (three severe varus knees) who underwent navigation‐assisted total knee arthroplasty (TKA) using arKA from April 2020 to September 2020 were included in this study, with an average age of 71.33 years (range, 61 to 80 years). General anesthesia was given to all patients. Intraoperative observations including tibia resection angle, frontal femoral angle, axial femoral angle, medial and lateral gap in the extension and flexion positions and joint line translation were recorded. Also, operation duration and drainage volume were recorded. Radiographic parameters including the mechanical axis (α), coronal femoral component angle (β), coronal tibial component angle (γ), sagittal femoral component angle (δ), tibial posterior slope angle (ε), femoral‐patella angle (θ), and femoral notching were assessed. Clinical evaluation was performed using the Hospital for Special Surgery (HSS) Score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Score. Both individual and mean measurement data were displayed.ResultsThe mean tibial resection was 4.00° varus (range, 3° to 5°), and the mean frontal femoral angle was 3.67° varus (range, 3° to 4°) in extension. The flexion lateral gap was wider than the medial gap with a mean laxity of 1.34 mm. Moreover, the mean axial femoral angle was 2.67° external (range, 0° to 6°) in flexion, and the mean joint line translation was 1.00 mm proximal (range, 0 to 3 mm). In addition, the mean preoperative mechanical axis was 156.22° (range, 153.65° to 158.90°) and the mean postoperative mechanical axis was 174.04° (range, 173.83° to 174.17°) with a mean correction of 17.82°. The mean femoral angle was 92.60° (range, 91.29° to 93.30°) and the mean tibial angle was 86.95° (range, 86.83° to 87.04°) in coronal plane. The HSS score improved from an average of 46.67 points (range, 42 to 51) preoperatively to 83.67 points (range, 81 to 86) at 3 months postoperatively. The mean WOMAC score was 16.33 points at 3 months postoperatively.ConclusionsThe new alignment technique of arKA aims to balance the flexion and extension gap without extensive releases of soft tissue and restore the native pre‐arthritic alignment, may be a promising alignment strategy for treating severe varus deformity. However, further study and comparison with other alignment techniques is needed.

To compare the clinical and radiographic results between primary total knee arthroplasty (TKA) via mini-subvastus or conventional approach through a prospective randomized controlled study. Ninety-four patients (104 knees) undergoing primary TKA between January 2011 and April 2012 were evaluated and randomly divided into 2 groups. Forty-six patients (52 knees) underwent TKA via conventional approach (conventional approach group), and 48 patients (52 knees) underwent TKA via mini-subvastus approach (mini-subvastus approach group). In these patients, 45 cases (51 knees) in conventional approach group and 45 cases (49 knees) in mini-subvastus approach group were followed up and recruited in the final analysis. There was no significant difference in age, gender, body mass index, sides, osteoarthritis grading, American Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, visual analogue scale (VAS), range of motion (ROM) of knee between 2 groups ( P>0.05). The clinical indexes were recorded and analyzed, including the operation time, length of incision, total blood loss, blood transfusion after operation, hospital stay time, the time of performing straight leg raise, incision condition, VAS score, ROM of knee, HSS score, and KSS score, hip-knee-ankle angle (HKA), femoral anatomic axis and the femoral prosthesis joint angle (femoral angle), tibia anatomic axis and tibial prosthesis joint angle (tibial angle), femoral prosthesis flexion angle (FPFA), and posterior slope angle (PSA) of the tibial plateau. All patients were followed up. The average follow-up time was 66.4 months (range, 60.0-72.5 months) in conventional approach group and 65.6 months (range, 60.0-71.2 months) in mini-subvastus approach group. Compared with the conventional approach group, the incision of mini-subvastus approach group shortened, the operation time prolonged, and the time when patients started straight leg raise exercises was earlier; showing significant differences between 2 groups ( P<0.05). There was no significant difference in hospital stay time, total blood loss, and numbers of blood transfusion between 2 groups ( P>0.05). The complication rate was 8.2% (4/49) in mini-subvastus approach group and 0 in conventional approach group, showing no significant difference between 2 groups ( P=0.054). At 1 and 3 days, the VAS and the ROM of knee in mini-subvastus approach group were significantly better than those in conventional approach group ( P<0.05); but there was no significant difference in above indexes between 2 groups at 14 day ( P>0.05). There was no significant difference in HSS and KSS scores between 2 groups at the 1, 3, 6, 12 months and 3, 5 years ( P>0.05). X-ray film showed no aseptic loosening in all cases. There was no significant difference in the measured values and incidence of abnormal patient of HKA, femoral angle, tibial angle, FPFA, and PSA at last follow-up between 2 groups ( P>0.05). TKA via mini-subvastus approach is helpful to the early function recovery of knee, but the long-term effectiveness is consistent with TKA via conventional approach. As the limited exposure, TKA via mini-subvastus spproach may has high risk of operative complications.

The aim of the study was to describe the differences in pelvic limb alignment between healthy purebred English Bulldogs and those with medial patellar luxation through the measurement of femoral and tibial angles on computed tomography images in multiplanar reconstruction modality (MPR-CT). Twenty-one purebred English Bulldogs were included and divided into two groups: one including healthy dogs (15 limbs) and the other including those with medial patellar luxation (24 limbs). Three different observers used MPR-CT to measure the following angles: anatomical lateral proximal femoral angle (aLPFA), anatomical lateral distal femoral angle (aLDFA), mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle of inclination of the femoral neck (AI), angle of anteversion (AA), mechanical medial proximal tibial angle (mMPTA), mechanical medial distal tibial angle (mMDTA), mechanical caudal distal tibial angle (mCdDTA), mechanical caudal proximal tibial angle (mCdPTA), and the tibial torsion angle (TTA). A Mann-Whitney U test was used to compare each variable in both groups. The values for aLDFA and mLDFA in the medial patellar luxation population were significantly increased compared to healthy subjects (p <0.05). No significant differences were observed for the other variables. In our population, an increased distal femoral varus was associated with medial patellar luxation. Our results could be useful to determine whether or not angular deformity of the femur is present and help determine the degree of correction necessary to restore alignment.

Introduction: A functional total knee replacement has to be well aligned, which implies that it should lie along the mechanical axis and in the correct axial and rotational planes. Incorrect alignment will lead to abnormal wear, early mechanical loosening, and patellofemoral problems. There has been increased interest of late in total knee arthroplasty with robotic assistance. This study was conducted to determine whether robot-assisted total knee arthroplasty is superior to the conventional surgical method with regard to the precision of implant positioning.Materials and Methods: Twenty knee replacements, comprising ten robot-assisted procedures and ten conventional operations, were performed on ten cadavers. Two experienced surgeons performed the surgeries. Both procedures on each cadaver were performed by the same surgeon. The choice of which procedure was to be performed first was randomized. Following implantation of the prosthesis, the mechanical axis deviation, femoral coronal angle, tibial coronal angle, femoral sagittal angle, tibial sagittal angle, and femoral rotational alignment were measured via 3D CT scanning. These variables were then compared with the preoperatively planned values.Results: In the knees that underwent robot-assisted surgery, the mechanical axis deviation ranged from −1.94° to 2.13° (mean: −0.21°), the femoral coronal angle from 88.08° to 90.99° (mean: 89.81°), the tibial coronal angle from 89.01° to 92.36° (mean: 90.42°), the tibial sagittal angle from 81.72° to 86.24° (mean: 83.20°), and the femoral rotational alignment from 0.02° to 1.15° (mean: 0.52°) in relation to the transepicondylar axis. In the knees that underwent conventional surgery, the mechanical axis deviation ranged from −3.19° to 3.84° (mean: −0.48°), the femoral coronal angle from 88.36° to 92.29° (mean: 90.50°), the tibial coronal angle from 88.15° to 91.51° (mean: 89.83°), the tibial sagittal angle from 80.06° to 87.34° (mean: 84.50°), and the femoral rotational alignment from 0.32° to 4.13° (mean: 2.76°) in relation to the transepicondylar axis. In the conventional knee replacement group, there were two instances of outliers outside the range of 3° varus/valgus for the mechanical axis deviation. The robot-assisted knee replacements showed significantly superior femoral rotational alignment results compared with conventional surgery (p = 0.006). There was no statistically significant difference between robot-assisted and conventional total knee arthroplasty with regard to the other variables. All the measurements showed high intra-observer and inter-observer reliability.Conclusion: Robot-assisted total knee arthroplasty showed excellent precision in the sagittal and coronal planes of the 3D CT scan. In particular, the robot-assisted technique showed better accuracy in femoral rotational alignment compared to the conventional surgery, despite the fact that the surgeons who performed the operations were more experienced and familiar with the conventional method than with robot-assisted surgery. It can thus be concluded that robot-assisted total knee arthroplasty is superior to conventional total knee arthroplasty.

The efficacy and accuracy of computer navigation have been proved during recent years. But most of recent studies focused on the coronal alignment in total knee arthroplasty and less on sagittal alignment. We retrospectively compared the results of the radiographs of 35 primary TKAs using a non-image based navigation system and 36 primary TKAs using fluoroscopy-assisted conventional technique. To compare the radiographic results, the following parameters were measured: mean mechanical femorotibial angle, mean femorotibial anatomical angle, mean coronal femoral component angle, mean coronal tibial component angle, mean sagittal femoral component angle, and mean sagittal tibial component angle. The navigation TKA showed better accuracy and consistency in mechanical axis deviation, coronal femoral component angle, and sagittal tibial component angle. The coronal tibial component position was acceptable in both groups. The navigation TKA markedly improved the restoration of mechanical axis, but not so much in sagittal femoral component position. The fluoroscopy-assisted conventional TKA had a tendency that femoral component was inserted in flexed position than in navigation TKA. Unlike the fluoroscopy-assisted conventional TKA, the femoral component was inserted in slightly extended position in the navigation TKA than expected. In conclusion, even though the use of navigation in TKAs help the surgeon to achieve good results, the surgeon should know the tendency of extension of the femoral component in sagittal plane to avoid anterior notching.

The incidence of low back pain (LBP) is high in patients with hip osteoarthritis (OA). Evidence from previous studies suggests that lumbar alignments and hip range of motion (ROM) are important etiological factors for LBP. However, no studies have investigated which factors that have the greatest influence on LBP. This investigation aimed to collectively examine factors related to LBP in patients with hip OA, including lumbar lordosis angle (LLA), leg length discrepancy (LLD), and hip ROM. Thirty-five patients participated in this study. LBP was treated as a dependent variable, whereas hip ROMs were treated as independent variables. Patients' age and body mass index (BMI) were recorded as confounding factors, as were LLA and LLD. A logistic regression model was performed to determine the most accurate set of variables to predict LBP. BMI and ROM of hip flexion on the affected side were identified as significant variables. Our results suggest that BMI and ROM of hip flexion on the affected side are related to LBP in patients with hip OA and need to be assessed.

To assess the symmetry of coronal alignment in the lower limbs of patients with knee osteoarthritis to evaluate whether the contralateral lower limb can serve as a reliable reference for guiding coronal positioning and alignment in total knee arthroplasty (TKA) surgery. This is a multicentric cross-sectional observational study. Preoperative full-leg weight-bearing radiographies from patients with knee osteoarthritis treated with a TKA between 2022 and 2024 were analyzed. Radiological parameters were measured in both lower limbs: medial proximal tibial angle, tibial mechanical angle (TMA), lateral distal femoral angle, femoral mechanical angle (FMA), hip-knee-ankle angle (HKA) and Kellgren-Lawrence. Lower limb coronal symmetry was assessed using the HKA, coronal plane alignment of the knee (CPAK) and phenotypes classifications. The relationship between concordance rates and osteoarthritis severity and symmetry was also analyzed. Seventy-six patients were included. The operated-to-contralateral concordance for the HKA classification was 57%. It was higher when the operated knee was neutral (81%), compared to varus (58%) or valgus (27%). The CPAK concordance was 38%; it was similar across different CPAK types. The phenotype classification concordance was only 11%; 30% for the HKA parameter, 39% for FMA and 34% for TMA. There was no relationship between osteoarthritis severity or symmetry and coronal concordance rates. Patients with knee osteoarthritis have poor side-to-side symmetry in lower limb coronal alignment. The concordance rate was 56% for the HKA classification, 39% for the CPAK classification and 11% for the phenotype classification. Therefore, the contralateral lower limb may not be a reliable reference for guiding coronal positioning and alignment in TKA surgery. Level III.

Objective: To investigate the influence of correction degree on the clinical effect of valgus knee after total knee arthroplasty(TKA). Methods: Clinical data of 91 patients with unilateral valgus knee who underwent TKA from January 2015 to December 2018 at Department of Orthopaedic Surgery,Zhongda Hospital,Southeast University were retrospectively analyzed. According to postoperative hip-knee-ankle angle(HKA),these patients were divided into neutral group (-3°≤HKA≤3°) and residual valgus group(HKA>3°). There were 70 patients in the neutral group,with a median age of 71.5 years(range:57 to 91 years),and 21 patients in the residual valgus group,with a median age of 71.5 years(range:60 to 85 years). The postoperative clinical indicators,including the range of motion (ROM),American Knee Society score(KSS),Western Ontario and McMaster University(WOMAC) osteoarthritis index,forgotten joint score (FJS-12) were collected. Meanwhile,the imaging indexes of femoral angle,tibial angle,femoral prosthesis flexion angle,tibial prosthesis posterior slope angle,patella tilt angle,congruence angle were also collected. Additionally,postoperative complications were recorded. The clinical data were analyzed by independent sample t test,Mann-Whitney U test or χ2 test. Results: There were no differences between the two groups in postoperative ROM (122.5°±8.5° vs. 119.4°±7.1°,t=1.534,P=0.128),KSS(159.8±8.9 vs. 150.0±8.9,t=-0.103,P=0.918),WOMAC osteoarthritis index(10.0(3.0) vs. 9.0(5.0),Z=-0.733,P=0.464),FJS-12(52.1(8.4) vs. 50.1(7.5),Z=-0.594,P=0.553)and femoral angle(94.0°(4.0°) vs. 94.0°(5.0°),Z=-0.209,P=0.835),tibial angle(90.0°(3.0°) vs. 91.0°(2.5°),Z=-1.226,P=0.220),femoral prosthesis flexion angle(3.0°(1.0°) vs. 3.0°(1.0°),Z=-0.652,P=0.514),tibial prosthesis posterior slope angle(4.0°(2.0°) vs. 4.0°(2.0°),Z=-0.763,P=0.445),patella tilt angle(9.0°(3.0°) vs. 9.0°(3.5°),Z=-1.429,P=0.153),congruence angle(14.0°(4.0°) vs. 15.0°(4.0°),Z=-1.690,P=0.091). However,abnormal proportions of patella tilt angle(33.3% vs.11.4%,χ²=5.630,P=0.018) and congruence angle(38.1% vs.17.1%,χ²=4.136,P=0.042) were apparent in the residual valgus group. The patients were follow-up for (32.1±5.2) months(range:24 to 40 months). Six weeks after operation,one case of joint stiffness occurred in the residual valgus group, which was improved after manual relaxation and rehabilitation exercises. At the last follow-up,two cases in the residual valgus group suffered patella instability which were fixed by patella braces and strengthening of the medial femoral muscles. There were no cases requiring reoperation for dislocation of patella,joint instability and aseptic loosening of the prosthesis in both groups. Conclusions: Residual valgus after TKA for valgus knee has no significant effect on the short-term clinical outcome,but it is more likely to cause abnormal proportions of patella tilt angle and congruence angle which may induce the risk of postoperative patella instability. The mid-and long-term outcomes need to be further investigated.

Circular fixators have been used successfully to correct multiplanar deformities but are often cumbersome and may be difficult to apply. We determined whether a monolateral fixator, which allows for correction of angular deformity and displacement in three planes, can correct lower extremity deformities to within normal radiographic means (anatomic lateral distal femoral angle, anatomic medial proximal tibial angle, and tibial femoral angle). We retrospectively reviewed the clinical records and radiographs of 22 consecutive patients (25 limbs) who underwent deformity correction using a new multiaxial monolateral external fixator. The patients were 4 to 16 years of age. We had a minimum 1.2-year followup (mean, 2.14 years; range, 1.2-3.1 years). Those with primary femoral and tibial deformities had improvements in the mean deviation from normal of the anatomic lateral distal femoral angle, anatomic medial proximal tibial angle and tibial femoral angle. Patients with Blount's disease had improvements in the mean anatomic medial proximal tibial angle from 59.9 masculine to 87.8 masculine. Five patients had complications (two pin site infections, one premature consolidation, one knee flexion contracture, one recurrence of varus). Six patients developed secondary deformities, all of which were corrected using the primary or secondary hinge. We conclude this fixator can produce satisfactory results with relatively few complications. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The lower limb alignment is influenced by the geometry of the joint surfaces and surrounding soft tissue tension. The mechanical behavior changes in a normal, osteoarthritic, and postoperative knee. The purpose of this study is to determine the dynamic coronal femoral tibial mechanical angle (FTMA) in osteoarthritic knees using computer navigation. The authors hypothesize that there are different varus-valgus patterns between flexion and extension in the osteoarthritic knee. We conducted a transversal observational study and included patients with osteoarthritis who underwent primary navigation TKA (Orthopilot version 4.2; B. Braun Aesculap, Tuttlingen, Germany). In total, 98 consecutive patients with 100 osteoarthritic knee joints, on which total knee arthroplasty was performed in our institution from 2009 to 2010, were enrolled in this prospective study. The FTMA was measured with the patient supine with maximum knee extension possible (considering the value as 0), 30, 60, and 90 degrees. All FMTA data obtained were segmented by hierarchic cluster measuring method. Through the clustering system, five segments were generated for varus patients and three for valgus patients: expected varus, expected valgus, severe varus, severe valgus, structured varus, structured valgus, concave varus, mixed varus-valgus, and mixed valgus-varus. The findings of the present study have demonstrated that there is a well-defined dynamic alignment in osteoarthritic knees, resulting in a wide kinematic variation in the coronal FTMA between flexion and full extension. Further studies will be necessary to determine whether this dynamic approach to FTMA has clinical utility in the surgeon's decision-making process.