Purpose
Knee adduction moment (KAM) has been recognized as a good clinical surrogate for medial tibiofemoral joint loading and is associated with implant durability after total knee arthroplasty ...(TKA). This study aimed to examine the effects of joint line obliquity in kinematically aligned TKA (KA-TKA) on KAM during gait.
Methods
The study enrolled 21 knees from 18 patients who underwent cylindrical axis reference KA-TKA and a matched group of 21 knees from 18 patients who underwent mechanically aligned (MA)-TKA as controls. Gait analyses were performed the day before TKA and at an overall mean of 2.6 years postoperatively. First peak KAM and variables associated with frontal knee kinetics were determined and compared between groups.
Results
In KA-TKA, the proximal tibia was resected with 3.4° ± 1.5° of varus in relation to the mechanical axis, and the final femorotibial shaft axis was 176.7° ± 3.8° with KA-TKA and 174.4° ± 3.0° with MA-TKA. KAM was significantly smaller with KA-TKA than with MA-TKA (
p
< 0.032). Regarding variables affecting KAM, significant differences were evident between the two TKAs for knee adduction angle (
p
= 0.0021), lever arm (
p
= 0.028), and Δlever arm (
p
= 0.0001).
Conclusions
In KA-TKA, joint line obliquity reduced peak KAM during gait, despite slight varus limb alignment, and this reduced KAM in KA-TKA can tolerate constitutional varus alignment. In clinical settings, KA-TKA thus represents a promising technical option for patients with large coronal bowing of the shaft carrying a risk of increased KAM after TKA.
Level of evidence
III.
Background:
Although various reconstruction techniques are available for anterior cruciate ligament (ACL) injuries, a long recovery time is required before patients return to sports activities, as ...the reconstructed ACL requires time to regain strength. To date, several studies have reported use of mesenchymal stem cells in orthopaedic surgery; however, no studies have used adipose-derived stem cell (ADSC) sheets in ACL reconstruction (ACLR).
Hypothesis:
ADSC sheet transplantation can improve biomechanical strength of the autograft used in ACLR.
Study Design:
Controlled laboratory study.
Methods:
A total of 68 healthy Japanese white rabbits underwent unilateral ACLR with a semitendinosus tendon autograft after random enrollment into a control group (no sheet; n = 34) and a sheet group (ADSC sheet; n = 34). At 2, 4, 8, 16, and 24 weeks after surgery, rabbits in each group were sacrificed to evaluate tendon-bone healing using histological staining, micro–computed tomography, and biomechanical testing. At 24 weeks, scanning transmission electron microscopy of the graft midsubstance was performed.
Results:
The ultimate failure load for the control and sheet groups, respectively, was as follows: 17.2 ± 5.5 versus 37.3 ± 10.3 (P = .01) at 2 weeks, 28.6 ± 1.9 versus 47.4 ± 10.4 (P = .003) at 4 weeks, 53.0 ± 14.3 versus 48.1 ± 9.3 (P = .59) at 8 weeks, 66.2 ± 9.3 versus 95.2 ± 43.1 (P = .24) at 16 weeks, and 66.7 ± 27.3 versus 85.3 ± 29.5 (P = .39) at 24 weeks. The histological score was also significantly higher in the sheet group compared with the control group at early stages up to 8 weeks. On micro–computed tomography, relative to the control group, the bone tunnel area was significantly narrower in the sheet group at 4 weeks, and the bone volume/tissue volume of the tendon-bone interface was significantly greater at 24 weeks. Scanning transmission electron microscopy at 24 weeks indicated that the mean collagen fiber diameter in the midsubstance was significantly greater, as was the occupation ratio of collagen fibers per field of view, in the sheet group.
Conclusion:
ADSC sheets improved biomechanical strength, prevented bone tunnel enlargement, and promoted tendon-bone interface healing and graft midsubstance healing in an in vivo rabbit model.
Clinical Relevance:
ADSC sheets may be useful for early tendon-bone healing and graft maturation in ACLR.
Risk for non-contact anterior cruciate ligament (ACL) injury can be assessed based on drop vertical jump (DVJ). However, biomechanics of DVJ may differ with various sporting activities. The purpose ...of the present study was to clarify whether biomechanical features of DVJ are different among various sporting activities in female athletes.
A total of 42 female athletes, including 25 basketball, 8 soccer and 9 volleyball players, participated in the current investigation. DVJ was done for each female athlete using a three-dimensional motion analysis system which consisted of six cameras, two force plates and 46 retro-reflective markers. Kinematic and kinetic data were recorded for both limbs in each athlete. Simultaneously, frontal and sagittal plane views of the DVJ were recorded using two different high-resolution video cameras to evaluate Landing Error Scoring System (LESS) score. Three-dimensional biomechanical parameters at the knee joint and LESS were compared among three different sporting activities using ANOVA or Kruskal-Wallis test after confirming normality assumption. Thereafter post hoc Tukey or Steel-Dwass was utilized for multiple comparison.
Soccer players had better LESS score, and peak knee flexion angle was significantly larger in soccer players compared to the other sports. In addition, knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle, and knee abduction moment within 40 ms from IC were significantly smaller in soccer players, compared to basketball players. In terms of volleyball players, knee abduction angle at IC and knee internal rotation angle at IC were significantly larger than soccer players, whereas no significant biomechanical differences were found between basketball and volleyball players.
From the present study, female basketball and volleyball players have worse LESS score, smaller peak knee flexion angle, greater knee abduction angle at IC and greater knee internal rotation angle at IC, compared to female soccer players. Thus, female basketball and volleyball players may have an increased risk of non-contact ACL injury during the jump-landing task, compared to soccer players. Biomechanics of DVJ depends on characteristics of the athlete's primary sport.
Recently, poor patient satisfaction after total knee arthroplasty (TKA) has gained attention mainly in osteoarthritis (OA) patients; however, satisfaction after TKA remains to be understood in ...rheumatoid arthritis (RA) patients. This study aimed to examine satisfaction and function after RA TKA using patient-reported outcome measures and to compare the results with those of OA-TKA.
This study enrolled 534 TKAs of 501 patients consisting of 75 TKAs of 70 RA patients and 459 TKAs of 431 OA patients. Data of patient-reported outcome measures such as new Knee Society Score 2011, Pain Catastrophizing Scale, and Pain DETECT Score were collected at 2 years. Multiple regression analysis was performed with Knee Society Score satisfaction score set as a dependent variable in order to clarify factors affecting patient satisfaction. Principle component analysis was performed, and satisfaction and function components were compared between RA and OA.
All activity scores were significantly lower in RA TKA than in OA TKA, whereas the range of motion and patient satisfaction scores were significantly better in RA TKA than in OA TKA. Scores for symptom, expectation, basic activity, and discretional activity positively affected patient satisfaction (P < .001), while Pain Catastrophizing Scale negatively did (P = .021). Importantly, diagnosis of RA itself pushed up the patient satisfaction score by 1.5 points. Principle component analysis revealed that RA TKA achieved significantly higher satisfaction component (P = .001), but lower function component (P < .0001) compared to OA TKA.
Patient satisfaction was better but functional activity was lower in RA than in OA. As poor functional activity was evident preoperatively in RA patients, to improve functional outcome should be future challenge for RA TKA.
Our research group aims to develop an osteochondral composite using type II collagen gel with hydroxyapatite (HAp) deposited on one side. Soaking gels in Ca
2+ and phosphate solution is indispensable ...to HAp deposition, so relationships between cell behavior and Ca
2+ concentration were examined in two- and three-dimensional cultures. The present results indicate that 2–4
m
M Ca
2+ is suitable for proliferation and survival of osteoblasts, whereas slightly higher concentrations (6–8
m
M) favor osteoblast differentiation and matrix mineralization in both 2- and 3-dimensional cultures. Higher concentrations (>
10
m
M) are cytotoxic. Purely from the perspective of calcium deposition, higher concentrations lead to increased accumulation of Ca
2+.
Culturing cells in phosphate-containing gel in media with Ca
2+ also leads to time-dependent formation of HAp in the gel. Considering the viability of embedded cells, culturing scaffolds in media with Ca
2+ concentrations around 5
m
M is useful for both HAp deposition and osteoblast behavior.
•The upright knee rotational alignments were measured by upright computed tomography.•The tibial anteroposterior axis was changed under upright, weight-bearing conditions.•The tibia rotated 7.4° more ...externally under upright, weight-bearing conditions than under supine non-weight-bearing conditions.
The traditional anteroposterior (AP) axis (i.e., Akagi’s line) has been widely used as the tibial component AP axis during total knee arthroplasty (TKA). However, this AP axis has been defined based on computed tomography (CT) in a non-weight-bearing supine position. In this study, AP axes of the tibial plateau from upright CT in weight-bearing and non-weight-bearing positions were determined and compared.
This study included 43 knees from 23 healthy volunteers. CT images were obtained in weight-bearing and non-weight-bearing standing positions using a 320-detector row upright CT scanner. The line perpendicular to surgical transepicondylar axis projected onto the tibia plateau was determined as the AP axis in upright weight-bearing and non-weight-bearing conditions. Angular differences between these two conditions were measured.
The upright weight-bearing AP axis was positioned in a mean of 7.4 ± 4.3° of internal rotation relative to the traditional AP axis. Distance between the traditional and upright weight-bearing AP axis was 2.9 ± 1.6 mm at the edge of the tibial plateau. The upright non-weight-bearing AP axis was positioned in a mean of 3.5 ± 4.1° of internal rotation relative to the traditional AP axis. Mean angular difference between weight-bearing and non-weight-bearing conditions was 3.9 ± 4.1°.
The upright weight-bearing AP axis was positioned in 7.4° of internal rotation relative to the traditional AP axis, showing one-seventh of the tibial tuberosity away from the medial border of the tibial tubercle, which represents a practical landmark for the tibial component AP axis during TKA.
Although the external knee adduction moment (KAM) during gait was shown to be a quantitative parameter of medial knee osteoarthritis (OA), it requires expensive equipment and a dedicated large space ...to measure. Therefore, it becomes a major reason to limit KAM measurement in a clinical environment. The purpose of this study was to estimate KAM using a single inertial measurement unit (IMU) during gait in patients with knee OA. A total of 22 medial knee OA patients (44 knee joints) performed conventional gait analysis using three-dimensional (3D) motion capture system. At the same time, we attached commercial IMUs to six body segments (sternum, pelvis, both thighs, and both shanks), and IMU signals during gait were recorded synchronized with the motion capture system. The peak-to-peak difference of acceleration in the lateral/medial axis immediately after heel contact was defined as the thrust acceleration (TA). We hypothesized that TA would represent the lateral thrust of the knee during the stance phase and correlate with the first peak of KAM. The relationship between the peak KAM and TA of pelvis (R = 0.52,
< 0.001), shanks (R = 0.57,
< 0.001) and thighs (R = 0.49,
= 0.001) showed a significant correlation. The root mean square error (RMSE) of linear regression models of pelvis, shanks, and thighs to estimate KAM were 0.082, 0.079, and 0.084 Nm/(kg·m), respectively. Our newly established parameter TA showed a moderate correlation with conventional KAM. The current study confirmed our hypothesis that a single IMU would predict conventional KAM during gait. Since KAM is known as an indicator for prognosis and severity of knee OA, this new parameter has the potential to become an accessible predictor for medial knee OA instead of KAM.
Rheumatoid arthritis (RA) is a multi-factorial disease characterized by chronic inflammation and destruction of multiple joints. To date, various biologic treatments for RA such as anti-tumor ...necrosis factor alpha antibodies have been developed; however, mechanisms underlying RA development remain unclear and targeted therapy for this condition has not been established. Here, we provide evidence that signal transducer and activator of transcription 3 (Stat3) promotes inflammation and joint erosion in a mouse model of arthritis. Stat3 global KO mice show early embryonic lethality; thus, we generated viable Stat3 conditional knockout adult mice and found that they were significantly resistant to collagen-induced arthritis (CIA), the most common RA model, compared with controls. We then used an in vitro culture system to screen ninety-six existing drugs to select Stat3 inhibitors and selected five candidate inhibitors. Among them, three significantly inhibited development of arthritis and joint erosion in CIA wild-type mice. These findings suggest that Stat3 inhibitors may serve as promising drugs for RA therapy.
Rheumatoid arthritis (RA) is a disease characterized by chronic joint inflammation, pain and joint destruction, leading to alteration in activities of daily living, yet pathological mechanisms ...underlying the condition are not fully clarified. To date, various therapeutic agents have been developed as RA therapy including DMARDs and/or biological agents that target inflammatory cytokines or inhibit JAK. Here we asked whether inhibiting signal transducer and activator of transcription 3 (Stat3) activity would antagonize RA.
Stat3 forms dimers when activated and undergoes nuclear translocalization; thus we screened approximately 4.9 million small compounds as potential blockers of protein-protein interactions required for Stat3 dimerization using in silico screening. We identified 15 as strong candidates as potential blockers of protein-protein interactions required for Stat3 dimerization using in silico screening from those compounds. Four of the 15 significantly inhibited expression of IL-6 and RANKL, both of which are direct targets of Stat3, induced by IL-6. Among four, one compound, F0648-0027, significantly inhibited arthritis development without apparent adverse effects in vivo in collagen-induced arthritis model mice. F0648-0027 also significantly blocked Stat3 phosphorylation and nuclear localization following IL-6 stimulation of fibroblasts. These data suggest that Stat3 is a target for collagen-induced arthritis in mice, and that F0648-0027 could serve as a therapeutic reagent against comparable conditions in humans.
•Stat3 inhibiting compounds were screened from approximately 4.9 million compounds.•F0648-0027 was isolated as the most effective Stat3 inhibitor in vitro and in vivo.•Phosphorylation of Stat3 by IL-6 stimulation was inhibited by F0648-0027.•Nuclear translocation of Stat3 by IL-6 stimulation was inhibited by F0648-0027.•Arthritis score in RA mouse models was significantly inhibited by F0648-0027.
Purpose
One of the most widely used benchmarks of lower-limb alignment is the mechanical axis (MA), which passes through the centers of the femoral head and the ankle in the weight-bearing position. ...However, where the MA passes through three-dimensionally (3D) is unclear. We investigated the MA in 3D (3D-MA) in knee osteoarthritis (OA) using upright computed tomography (CT).
Materials and methods
This study included 66 varus OA knees from 38 patients age 70.0 (64.8–77.0) years; median (interquartile range). The 3D-MA was determined using upright CT data and compared among Kellgren–Lawrence (KL) grades. Further, correlations between the 3D-MA and other parameters were evaluated.
Results
The 3D-MA was located at 5.3 (1.3–14.4)% medially and 7.1 (0.7–15.3)% posteriorly on the tibial plateau in KL-1, and was translated medioposteriorly with increased KL grade. The 3D-MA in KL-3 30.6 (22.6–42.6)% medially and 50.9 (45.8–80.2)% posteriorly and KL-4 56.7 (48.5–62.9)% medially and 92.3 (50.2–127.1)% posteriorly was located extra-articularly. The mediolateral position of the 3D-MA correlated with the femorotibial angle correlation coefficient (CC) = − 0.85, p < 0.001, and the anteroposterior position of the 3D-MA correlated with the knee flexion angle (CC = − 0.93, p < 0.001).
Conclusion
Our analysis demonstrated that the 3D-MA in low-grade OA knees passes slightly medial and posterior to the knee center, and the 3D-MA is translated medioposteriorly with the progression of knee OA. Further, the 3D-MA is translated medially with varus progression and posteriorly with the progression of knee flexion contracture.
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