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Isolated talonavicular arthrodesis is one of the surgical procedures for patients with talonavicular arthritis. However, the 3-dimensional kinematic behavior of the hip, knee, and foot/ankle complex during walking after the arthrodesis remains unclear. The clinical outcomes and gait analyses of 2 cases who underwent isolated arthrodesis for talonavicular osteoarthritis with chronic dislocated navicular fracture are presented. Gait analysis was carried out in both cases 1 year after surgery to clarify the side-to-side differences in the ranges of motion of the hip, knee, and foot/ankle complex during walking. Both cases showed good clinical results and radiographic bone union. The kinematic data of the gait analyses showed considerable restriction in the range of motion of the ankle in all 3-dimensional planes for the fused foot compared with the contralateral side. Additionally, hyperextension of the knee in the late stance of gait on the operated side was observed in both cases. When talonavicular arthrodesis was performed for talonavicular osteoarthritis with chronic dislocated navicular fracture, postoperative generalized stiffness of the ankle and future disorder of the knee should be considered. Levels of Evidence: Level V: Case report.

The aim of this study was to quantify and visualize the degenerative patterns of the talus in ankle osteoarthritis (OA). The differences in talar morphology between sides of patients with unilateral varus ankle OA (medial talar tilt > 4°) were compared. Computed tomography images of both feet of 35 patients (OA: 22 patients, control: 13 patients) were analyzed. Each surface model of the right and left tali was registered to the opposite talus via a mirror-image technique and an iterative closest point algorithm. The surface deviation between the two models was quantified and visualized by deviation color maps. The results quantitatively demonstrated that osteophytes are generated in the area under the antero-medial margin of the trochlea in OA tali. In severe OA tali, bone resorption of more than 2 mm in the medial portion of the trochlea, as well as a similar degree of osteophyte formation on the lateral surface, was also seen. Stereotypical patterns of degeneration occurring in OA tali were successfully visualized and quantified by left-right comparison of patients with unilateral ankle OA. Such information would contribute to better understanding of the development of ankle OA and preoperative planning of total ankle arthroplasty and arthrodesis.

Objective: Vascular endothelial growth factor 165 (VEGF165) and its receptors, including neuropilin 1 (NRP-1), are overexpressed in human osteoarthritic (OA) articular cartilage, although their functional roles in the cartilage are not fully understood. An axon-guidance molecule, semaphorin 3A (Sema3A), which binds to NRP-1, acts as an antagonist of VEGF signaling in endothelial cells. The aim of this study was to examine the expression of Sema3A and the functions of the VEGF165/Sema3A/NRP-1 axis in OA cartilage., Methods: The expression of Sema3A in OA and normal cartilage samples was examined by real-time polymerase chain reaction and immunohistochemical analyses. Functional analyses of VEGF165 and Sema3A were carried out using OA chondrocytes in culture. The migration activity of chondrocytes was examined in a monolayer wound assay. The effects of Sema3A on VEGF165-induced up-regulation of matrix metalloproteinases (MMPs) and intracellular signaling were also studied in cultured chondrocytes., Results: Sema3A expression was significantly elevated in OA cartilage as compared to normal cartilage. Sema3A immunoreactivity directly correlated with the Mankin score and with chondrocyte cloning. VEGF165 promoted the migration of chondrocytes, and this activity was suppressed by VEGF receptor 2 tyrosine kinase inhibitors. Sema3A antagonized the chondrocyte migration promoted by VEGF165, and the activity was blocked by a selective inhibitor of, or small interfering RNA for, Sema3A. VEGF165-induced overexpression of MMPs and phosphorylation of ERK and focal adhesion kinase in chondrocytes were inhibited by Sema3A., Conclusion: Our findings provide the first evidence that Sema3A is overexpressed, with a direct correlation with cloning, in OA cartilage and that it suppresses the VEGF165-promoted migration of chondrocytes. Our findings also suggest that Sema3A plays a role in chondrocyte cloning through inhibition of cell migration in OA cartilage., (Copyright © 2011 by the American College of Rheumatology.)

Purpose: Reproducing a functional flexion-extension axis (FEA) of the femur is key to achieving successful collateral ligament balance and joint line in total knee arthroplasty (TKA). This study compared the feasibility of cylindrical axis (CA)-reference bone cut and articular surface-reference bone cuts in reproducing the FEA for Japanese osteoarthritis patients.Methods: The study enrolled 122 knees from 86 patients who underwent primary TKA due to grade III or IV osteoarthritis. Data from pre-operative CT were reconstructed into three-dimensional (3D) models using 3D-planning software. Cylindrical radii of the condyles were measured, and femoral bone cut angles relative to anatomical landmarks were determined in the coronal and axial reference planes based on CA-reference and articular surface-reference methods.Results: Mean cylindrical radii for medial and lateral femoral condyles were 17.4 ± 1.6 and 17.3 ± 1.4 mm, respectively. Of the 122 knees, 46 exhibited >1 mm of difference between condyles. Fifty-three and 22 knees exhibited >2° of angular difference between CA-reference and articular surface-reference bone cuts in the coronal and axial planes. Mean angle of the CA and surgical epicondylar axis in 3D space was 4.6 ± 2.1°. As practical parameters for TKA, the angle between CA and IM rod was significantly larger than that between the distal articular surface line and IM rod in the coronal plane (p < 0.0001), indicating that CA-reference involves a smaller valgus bone cut of the distal femur than articular surface reference.Conclusions: CA-reference bone cut of the femur is preferable to articular surface-reference bone cut for reproducing FEA in Japanese OA patients, in whom more than one-third of knees exhibited asymmetry of radii between medial and lateral condyles. In clinical practice, the CA-reference bone cut represents a good technical option for kinematically aligned TKA in the Japanese population. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis (OA) and to clarify the gait parameters affecting the weight-bearing distribution during both standing and walking using gait analysis. Methods: Twenty-five patients (averaged 71 years) with symptomatic bilateral end-stage medial knee OA participated in this study. They performed relaxed standing, placing one foot on a force plate and thereafter, level walking. First, knee resultant force was calculated on bilateral knees during standing. The knees in each patient were divided into Higher and Lower force side for the definition of dominant side limb. Second, gait parameters in each subject were compared between both sides. Results: Each patient had large weight-bearing asymmetry, though passive range of motion, subjective pain level, femorotibial angle and radiographic disease severities were not significantly different between both sides. In standing, knees on Higher force side were significantly extended (11.2 ± 6.5°) than on Lower force side (14.4 ± 7.3°, P = 0.0086). Similarly, knees on Higher force side were also significantly extended at heel strike during gait. Besides, peak values of extension moment, knee adduction moment, knee adduction moment impulse and vertical force during gait were significantly greater on Higher force side. Conclusions: Ability to extend the knee in standing was considered to be an essential factor to decide loading condition. It is clinically important to examine the ability to extend the knee in standing when considering loading asymmetry during gait in patients with bilateral knee OA. Level of evidence: III. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

Background: Achievement of very deep knee flexion after total knee arthroplasty (TKA) can play a critical role in the satisfaction of patients who demand a floor-sitting lifestyle and engage in high-flexion daily activities (e.g., seiza-sitting). Seiza-sitting is characterized by the knees flexed >145º and feet turned sole upwards underneath the buttocks with the tibia internally rotated. The present study investigated factors affecting the achievement of seiza-sitting after TKA using posterior-stabilized total knee prosthesis with high-flex knee design.Methods: Subjects comprised 32 patients who underwent TKA with high-flex knee prosthesis and achieved seiza-sitting (knee flexion >145º) postoperatively. Another 32 patients served as controls who were capable of knee flexion >145º preoperatively, but failed to achieve seiza-sitting postoperatively. Accuracy of femoral and tibial component positions was assessed in terms of deviation from the ideal position using a two-dimensional to three-dimensional matching technique. Accuracies of the component position, posterior condylar offset ratio and intraoperative gap length were compared between the two groups.Results: The proportion of patients with >3º internally rotated tibial component was significantly higher in patients who failed at seiza-sitting (41 %) than among patients who achieved it (13 %, p = 0.021). Comparison of intraoperative gap length between patient groups revealed that gap length at 135º flexion was significantly larger in patients who achieved seiza-sitting (4.2 ± 0.4 mm) than in patients who failed at it (2.7 ± 0.4 mm, p = 0.007). Conversely, no significant differences in gap inclination were seen between the groups.Conclusions: From the perspective of surgical factors, accurate implant positioning, particularly rotational alignment of the tibial component, and maintenance of a sufficient joint gap at 135º flexion appear to represent critical factors for achieving >145º of deep knee flexion after TKA. [ABSTRACT FROM AUTHOR]

Abstract: Varus thrust is an abnormal lateral knee motion frequently seen in patients with medial knee osteoarthritis (OA) during gait. It is a worsening of the alignment in the stance phase of the gait cycle and closely relates to disease progression. In this study, we measured the thrust quantitatively using skin markers and examined the relationship to other static and dynamic parameters. Forty-four knees in 32 patients (mean age, 72years; range, 64–81years) who exhibited the radiographic OA at least grade 2 according to the Kellgren–Lawrence (K–L) scale were enrolled. Gait analysis was performed for each patient to measure the amount of thrust and knee adduction moment. The amounts of thrust in subjects with K–L grades 2 (25 knees), 3 (13 knees), and 4 (6 knees) were 2.4°(±1.3°), 2.8°(±1.4°), and 7.2°(±5.3°), respectively and the knee adduction moments were 3.6(±1.5) %BW⁎Ht, 3.9(±1.2) %BW⁎Ht and 6.9(±2.2%) BW⁎Ht, respectively. The amount of thrust also exhibited significant correlation to static radiographic alignment (R =0.47: 95% confidence interval 0.67–0.21, p =0.0038) and showed greater correlation to the knee adduction moment (R =0.73: 95% confidence interval 0.84–0.55, p <0.001), which has been identified as an important dynamic index of the disease. The amount of thrust, which is able to be measured by simple inexpensive equipment, correlated to static and dynamic parameters and may offer an important clinical index for knee OA. [Copyright &y& Elsevier]

Abstract: This study evaluated flexion angles and mechanical loads at the knee during weight-bearing deep flexion in patients with knee osteoarthritis (OA). Thirty-eight knees of 26 patients (mean age, 73 years; range, 58–81 years) with medial knee OA and 16 knees of 8 healthy volunteers (mean age, 63.4 years; range, 60–65 years) were enrolled. Patients were subdivided into two groups based on Kellgren and Lawrence OA grade: moderate OA (grade 2, 17 knees) or severe OA (grade 3 or 4, 21 knees). Motion analysis was performed while rising from maximal knee flexion with one leg for each subject. Maximum knee flexion angles and net quadriceps moments in the weight-bearing motion were compared among the two OA groups and healthy subjects. Mean maximum flexion angle in patients was 91±9°. Angles were about 30% smaller than passive range of motion (ROM). Mean angles in healthy subjects, moderate OA and severe OA were 102.7±5.0°, 95.6±7.7° and 86.5±7.2°, respectively, and net quadriceps moments during motion were 5.5±1.2%BW⁎Ht, 4.5±1.7%BW⁎Ht and 3.9±1.3%BW⁎Ht, respectively. Angles and moments were significantly lower in OA patients than in healthy subjects. Maximum flexion angles during weight-bearing rising correlated significantly with HSS score (r =0.63; 95% confidence interval, 0.40–0.78) and were significantly lower in severe OA patients compared to moderate OA. This measurement may offer an important clinical index for knee OA. [Copyright &y& Elsevier]