Krüppel-like factor 15 deficiency exacerbates osteoarthritis through reduced expression of peroxisome proliferator-activated receptor gamma signaling in mice.

OBJECTIVE: Krüppel-like zinc finger transcription factors (KLFs) play diverse roles in mammalian cell differentiation and development. In this study, we investigated the function of KLF15 in the progression of osteoarthritis (OA). METHODS: 0Destabilization of the medial meniscus (DMM) surgery was performed in 10-week-old male wild-type control (WT) mice and cartilage-specific KLF15 knockout (KO) mice. Histological analysis, immunohistochemistry, and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling staining were performed. Morphological changes were measured using microcomputed tomography. Six mice from each group were analyzed (total number of mice analyzed: 60). In vitro, immunofluorescence, quantitative reverse transcription-polymerase chain reaction, and western blot analyses were performed. RESULTS: KLF15 KO DMM mice exhibited significant cartilage degradation compared to WT mice. According to the Osteoarthritis Research Society International cartilage OA-histopathology scoring system, the mean sum score in KLF15 KO mice was significantly higher than that in WT mice at 8 weeks after surgery. Immunohistochemistry results revealed KLF15 KO mice exhibited reduced peroxisome proliferator-activated receptor gamma (PPARγ) expression, increased pIKKα/ß, a disintegrin-like and metalloproteinase with thrombospondin motifs (ADAMTS) 5, and Matrix metalloproteinases (MMP13) expression, and reduced Forkhead box O (FOXO1) and Light chain 3B (LC3B) expression. Inhibition of PPARγ phosphorylation accelerated the effects of interleukin (IL) 1ß-treatment in both KLF15 KO and WT chondrocytes, and activation of PPARγ expression canceled the IL1ß-induced catabolic effects. CONCLUSION: Our results indicated that the OA phenotype of KLF15 KO DMM mice was influenced by reduced PPARγ expression, including enhanced pIKKα/ß, ADAMTS5, and MMP13 expression, reduced autophagy, and increased apoptosis. KLF15 regulation may constitute a possible therapeutic strategy for the treating OA.

Trans patellar tendon sagittal tibial cut for lateral unicompartmental knee arthroplasty-location of the split- CT simulation study.

BACKGROUND: In lateral unicompartmental knee arthroplasty (UKA), a sagittal cut is often performed through the patellar tendon (PT). Although the approach is likely widely used, it has not been described in detail, especially regarding the site of the split. This study aimed to clarify where the split should be made. METHODS: This single-center retrospective cohort study included 49 consecutive patients and 51 knees with lateral osteoarthritis. Using preoperative computed tomography, we measured the distance from the medial edge of the PT to the intersection of the PT and the sagittal cutting line, defined as a line parallel to the Akagi's line and passing the tip of the lateral tibial spine. RESULTS: The sagittal cut line passed a mean of 45 ± 11% of the patellar tendon width from the PT medial edge. CONCLUSIONS: The tendon split should be made just medial to the center of the PT because it is where the sagittal cut line for lateral UKA passes.

Paracrine effect of the stromal vascular fraction containing M2 macrophages on human chondrocytes through the Smad2/3 signaling pathway.

The adipose-derived stromal vascular fraction (SVF) is composed of a heterogeneous mix of adipose-derived stem cells (ADSCs), macrophages, pericytes, fibroblasts, blood, and other cells. Previous studies have found that the paracrine effects of SVF cells may be therapeutic, but their role in osteoarthritis treatment remains unclear. This study aimed to investigate the therapeutic effect of SVF cells on chondrocytes. Chondrocytes were seeded on culture plates alone (control) or cocultured with SVF or ADSCs on cell culture inserts. After 48 h of coculture, chondrocyte collagen II, tissue inhibitors of metalloproteinases-3 (TIMP-3), and matrix metalloproteinases-13 (MMP-13) messenger RNA (mRNA) expression levels were evaluated using reverse-transcription polymerase chain reaction, and the transforming growth factor-ß (TGF-ß) levels in the supernatant were measured using ELISA. Immunohistochemical staining and flow cytometry were used to evaluate the macrophages in the SVF. These macrophages were characterized according to phenotype using the F4/80, CD86, and CD163 markers. To determine whether the Smad2/3 signaling pathways were involved, the chondrocytes were pre-treated with a Smad2/3 phosphorylation inhibitor and stimulated with the SVF, and then Smad2/3 phosphorylation levels were analyzed using western blot. The mRNA expression levels of various paracrine factors and chondrocyte pellet size were also assessed. Collagen II and TIMP-3 expression were higher in the SVF group than in the ADSC group and controls, while MMP-13 expression was the highest in the ADSC group and the lowest in the controls. TGF-ß levels in the SVF group were also elevated. Immunohistochemical staining and flow cytometry revealed that the macrophages in the SVF were of the anti-inflammatory phenotype. Western blot analysis showed that the SVF increased Smad2/3 phosphorylation, while Smad2/3 inhibitors decreased phosphorylation. Smad2/3 inhibitors also reduced the expression of various other paracrine factors and decreased chondrocyte pellet size. These findings suggested that the paracrine effect of heterogeneous cells, such as anti-inflammatory macrophages, in the SVF partly supports chondrocyte regeneration through TGF-ß-induced Smad2/3 phosphorylation.

Histopathological changes of synovial tissue in rheumatoid arthritis patients treated with TNF-α inhibitors or IL-6 inhibitors.

OBJECTIVES: To investigate the cell types that undergo apoptosis in TNF-α inhibitor (TNFI)- and IL-6 inhibitor (IL-6I)-treated synovia of RA patients, and to observe and compare histological changes in them. METHODS: Synovial tissue was collected during total knee arthroplasty from 20 RA patients who were divided into three groups based on RA treatment received: conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs, control group), TNFI, or IL-6I. Tissue samples were subjected to haematoxylin and eosin staining, terminal deoxynucleotidyl transferase fluorescein-deoxyuridine triphosphate nick end labelling (TUNEL), immuno-histochemistry (IHC) and immunofluorescence staining for, respectively, histopathological assessment, apoptosis detection and IHC evaluation and scoring. RESULTS: TUNEL-positive cells were detected surrounding the discoid fibrosis unique to the TNFI group, while those in the IL-6I group were distributed widely, especially surrounding the blood vessels. IHC revealed that in TNFI-treated tissue, CD86- and CD80-positive cells were detected only in the lining and sublining layer, while CD163- and CD206-positive cells were detected more broadly; in the IL-6I-treated tissue, all four were detected widely but their levels were lower than in the control group. Immunofluorescence also revealed macrophages mainly were the apoptotic cells in the lining and sublining layers of TNFI group. TUNEL Expression levels of CD20- and CD3-positive cells were remarkably lower in the IL-6I group, compared with the control and TNFI groups. CONCLUSIONS: TNFIs and IL-6Is target different action sites and synovial cell types, resulting in histopathological features of synovium distinct from one another.

Effectiveness of an accelerometer-based portable navigation for intraoperative adjustment of leg length discrepancy in total hip arthroplasty in the supine position.

BACKGROUND: This study aimed to examine the accuracy of the HipAlign® accelerometer-based portable navigation system by measuring the intraoperative leg length change of patients who underwent total hip arthroplasty (THA) and comparing the measured leg length discrepancy (LLD) determined by the navigation system and a freehand technique. METHODS: A total of 61 patients who underwent THA using the anterolateral approach in the supine position were included in this study and divided into two groups: those who underwent THA with navigation (Group N; N = 31) and with the freehand technique (Group F; N = 30). Statistical analyses were performed to compare the intraoperative leg length change, pre- and post-LLD, absolute values of post-LLD, and the number of patients with the postoperative LLD within 10 mm and 5 mm between the two groups. Additionally, we examined the correlation between the leg length change obtained through intraoperative navigation and measured from the radiographs. Moreover, to evaluate the navigation accuracy, we examined the correlation between the absolute error of leg length change and cup orientation. RESULTS: The postoperative LLD was significantly lower and the number of patients with the postoperative LLD within 5 mm was significantly higher in Group N, compared with Group F. Additionally, the amount of leg length change measured intraoperatively by the navigation system was strongly correlated with the values obtained by the postoperative radiographic measurement with a small absolute error and minimal wasted time. Moreover, a significant positive correlation was found between the absolute error of the leg length change and that of the cup inclination. CONCLUSIONS: Our study demonstrates that the accelerometer-based portable navigation system is useful for the intraoperative adjustment of leg length discrepancy during THA for patients in the supine position, as it provides good accuracy and minimizes required time for use.

The tibial lateral axis is a novel extraarticular landmark for detection of the tibial anteroposterior axis.

PURPOSE: Although the tibial rotation axis is significant in knee arthroplasty, no reliable extraarticular landmark has been proposed. We hypothesized that the tibial lateral axis (TLA), a tangential line of the lateral tibial surface, is perpendicular to the surgical epicondylar axis (SEA) and compared it to other existing landmarks by 3D-CT. METHODS: Fifty legs in 25 consecutive patients were studied. Using their preoperative CT, the TLAs were identified on slices at 10-50% of the total length of the tibia and the measured differences of angles against the line perpendicular to the SEA (the tibial AP axis) were calculated. The differences between the SEA and the femoral and tibial posterior condylar axis, Akagi's line and the line between the medial intercondylar spine and the medial border of the patellar tendon (sAP line)(intraarticular), the ankle axis, and the transmalleolar axis (extraarticular) were also calculated and compared. RESULTS: The mean values of TLA at 10%, 20%, 30% were virtually parallel to the SEA (0.97° ± 4.84°, 0.02° ± 4.61°, 1.10° ± 4.97°, respectively). They were equivalent to existing intraarticular landmarks and superior to existing extraarticular landmarks, and these levels corresponded to the tip to the lower end of the tibial tubercle (at 10.8% and 17.0% of total tibial length). CONCLUSION: The proximal TLAs can be an extraarticular bony landmark that indicates the line perpendicular to the SEA. A prospective study is needed to prove the validity and accuracy of the axes clinically.

A subcutaneous arthroscopic portal closure technique without thread exposure.

We present a simple new suture technique for an arthroscopic portal that enables a secured subcutaneous suture without thread exposure. A curved suture needle is inserted through the skin at approximately 1 cm from the wound edge. The needle penetrates the subcutaneous tissue and exits through the skin on the opposite side of the wound edge. The needle and suture are pulled from just underneath the skin layer. The thread is collected within the wound, and the other end of the thread is pulled from the wound. The needle is inserted at just beneath the skin layer, penetrates the subcutaneous tissue, and pierces the opposite side of the skin. The needle is retrieved along with the thread at approximately 1 cm from the other side of the wound edge. After removing the needle from the thread, the thread passing in the wound is located and the needle side of the thread is retrieved from the wound. The ends of the thread are tied under the appropriate tension. From our findings, we recommend this method for suturing of all arthroscopic portals, as well as other small incisions that need water-tight suture.

Prediction of Postoperative Range of Motion after Mobile-Bearing Medial Unicompartmental Knee Arthroplasty from the Preoperative Range of Motion and Other Preoperative Factors.

Postoperative flexion after unicompartmental knee arthroplasty might be predicted from the preoperative range of motion and other preoperative factors, but this has not been sufficiently investigated. Between 2013 and 2017, 198 patients (198 knees) underwent unilateral knee arthroplasty with medial mobile-bearing unicompartmental knee arthroplasty. Range of motion was measured preoperatively and at the time of final follow-up. To investigate the accuracy of the prediction of preoperative to postoperative gain or loss of the flexion angle, we performed receiver operating characteristic analysis. Logistic regression analysis was used to evaluate other predictive factors. Change in flexion angle was significantly strongly and negatively correlated with the preoperative flexion angle (R = - 0.688; 95% confidence interval: -0.755 to -0.607; p < 0.001). Preoperative flexion angle was suggested to be a significant predictor of gain or loss of the flexion angle with the area under the curve of 0.781; the cutoff value calculated using the Youden index was 140 degrees. Logistic regression analysis showed that in addition to the preoperative flexion angle of the operated side, the postoperative flexion range was significantly affected by the patient's height and by the preoperative flexion angle of the contralateral knee. If the preoperative flexion angle in Oxford mobile-bearing medial unicompartmental knee arthroplasty is <140 degrees, the postoperative flexion angle may be improved; if it exceeds 140 degrees, the postoperative flexion angle may worsen. This predictive ability is further improved by consideration of the patient's height and the range of motion on the contralateral side.

Heterogeneous Cells as well as Adipose-Derived Stromal Cells in Stromal Vascular Fraction Contribute to Enhance Anabolic and Inhibit Catabolic Factors in Osteoarthritis.

The stromal-vascular fraction (SVF), comprising heterogeneous cell populations and adipose-derived stromal cells (ADSCs), has therapeutic potential against osteoarthritis (OA); however, the underlying mechanism remains elusive. This study aimed to investigate the therapeutic effects of heterogeneous cells in rabbit SVF on rabbit chondrocytes. Rabbit SVF and ADSCs were autografted into knees at OA onset. The SVF (1 × 105) and low-dose ADSCs (lADSC; 1 × 104) groups adjusted for their stromal cell content were compared. Animals were euthanized 8 and 12 weeks after OA onset for macroscopic and histological analyses of OA progression and synovitis. Immunohistochemical and real-time polymerase chain reaction assessments were conducted. In vitro, immune-fluorescent double staining was performed for SVF to stain macrophages with F4/80, CD86(M1), and CD163(M2). OA progression was markedly suppressed, and synovitis was reduced in the SVF groups (OARSI histological score 8 W: 6.8 ± 0.75 vs. 3.8 ± 0.75, p = 0.001; 12 W: 8.8 ± 0.4 vs. 5.4 ± 0.49, p = 0.0002). The SVF groups had higher expression of collagen II and SOX9 in cartilage and TGF-ß and IL-10 in the synovium, lower expression of MMP-13, and lower macrophage M1/M2 ratio than the lADSC groups. Immunofluorescent double staining revealed a markedly higher number of M2 than that of M1 macrophages in the SVF. The therapeutic effects of SVF on chondrocytes were superior than those of lADSCs, with enhanced anabolic and inhibited catabolic factors. Heterogeneous cells, mainly M2 macrophages in the SVF, enhanced growth factor secretion and chondrocyte-protective cytokines, thus benefiting chondrocytes and knee joint homeostasis. Overall, the SVF is a safe, relatively simple, and a useful treatment option for OA.

Polyarthritis presented in a patient with untreated chronic hepatitis B infection.

Hepatitis B virus (HBV) infection can cause arthritis, but it is rarely reported. In the current report, we present a case of chronic polyarthritis in a patient with untreated HBV infection. A 63-year-old woman suffering from polyarthritis in her fingers visited our institution. She had experienced exacerbations and remissions of polyarthritis for more than 20 years. She had been diagnosed with rheumatoid arthritis and had been treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and nonsteroidal anti-inflammatory drugs by her primary care doctor, but the csDMARDs were discontinued at the request of the patient 10 years before the first visit to our hospital. The blood test showed negative for rheumatoid factor and anticyclic citrullinated peptides antibody but positive for hepatitis B surface antigen. Hepatitis B surface antigen and HBV-Deoxyribo Nucleic Acid (DNA) were increased to 312.6 (IU/ml) and 4.6 (log copies/ml), respectively. Based on the results of abdominal computed tomography and echography, she was diagnosed with liver cirrhosis. Treatment for HBV infection was begun with oral tenofovir at 25 mg/day. The polyarthritis in her fingers gradually disappeared and has not relapsed for 6 months after the initiation of treatment for HBV infection. When polyarthritis is diagnosed, the possibility that chronic HBV infection can be one of the causes of polyarthritis should be considered.

P21 deficiency exhibits delayed endochondral ossification during fracture healing.

INTRODUCTION: Endochondral ossification is a complex biological phenomenon involving a variety of factors and cells. Cyclin-dependent kinase inhibitor 1 (p21) inhibits cell cycle progression and is affected by external stress. We recently reported that embryonic endochondral ossification is unaffected by endogenous p21 deficiency. In this study, we evaluated whether p21 expression affects endochondral ossification during fracture healing. METHODS: Tibial fractures were introduced into p21 knockout (p21-/-) (n = 24) and wild-type C57BL/6 (p21+/+) (n = 24) mice at age 10 weeks. Fracture healing was evaluated using radiological, histological, and immunohistochemical (IHC) analyses. The effect of p21 small interfering RNA (siRNA) on ATDC5 cells was assessed in vitro. RESULTS: The Allen score for fracture healing was lower in p21-/- mice than in p21+/+ mice. In addition, p21-/- mice exhibited larger calluses and lower bone mineral density. IHC analyses showed that p21-/- mice exhibited delayed endochondral ossification via the Ihh-Runx2-Osterix pathway in vivo. Down-regulation of p21 expression in ATDC5 cells delayed endochondral ossification in vitro. CONCLUSIONS: p21 deficiency leads to delayed endochondral ossification by attenuating the Ihh-Runx2-Osterix pathway in vivo, and p21 deficiency in hypertrophic chondrocytes causes delayed differentiation of hypertrophic chondrocytes in vitro. p21 plays a role in endochondral ossification during fracture healing.

Cryopreserved human adipose-derived stromal vascular fraction maintains fracture healing potential via angiogenesis and osteogenesis in an immunodeficient rat model.

BACKGROUND: Novel therapeutic strategies for the healing of nonunion, which has serious effects on the quality of life of patients, are needed. We evaluated the therapeutic effect of local transplantation of human stromal vascular fraction (SVF) cells on fracture healing in a rat non-healing fracture model and compared the effects between freshly isolated (F) and cryopreserved (C)-SVFs. METHODS: Non-healing fracture model was induced in the femur of female immunodeficient rats (F344/N Jcl rnu/rnu) with cauterizing periosteum. Immediately after the creation of non-healing fracture, rats received local transplantation of F and C-SVFs suspended in phosphate-buffered saline (PBS) or the same volume of PBS without cells using the same scaffold as a control group. During 8 weeks post-surgery, radiologic, histological, immunohistochemical, and biomechanical analyses were performed to evaluate fracture healing. The comparison of radiological results was performed with a chi-square test, and the multiple comparisons of immunohistochemical, histological, and biomechanical results among groups were made using a one-way analysis of variance. A probability value of 0.05 was considered to denote statistical significance. RESULTS: At week 8, in 60% of animals receiving F-SVF cells and in 50% of animals receiving C-SVF cells, the fracture radiologically healed with bone union whereas nonunion was observed in the control group. The healing potential was also confirmed by histological and biomechanical assessments. One of the mechanisms underlying healing involving intrinsic angiogenesis/osteogenesis was enhanced in F- and C-SVF groups compared with that in the control group. Human cell-derived vasculogenesis/osteogenesis, which was also confirmed in an in vitro differentiation assay, was also enhanced in the F- and C-SVF groups compared with that in the control groups and could be another mechanism for healing. CONCLUSIONS: SVF cells can enhance bone healing and cryopreserved cells have almost equal potential as fresh cells. SVF cells can be used for improving nonunion bone fracture healing as an alternative to other mesenchymal stem cells and the effect of SVF cells can be maintained under cryopreservation.

Comparison of clinical and biomechanical outcomes between the kinematic and mechanical alignment methods in total knee arthroplasty: Protocol for a multicenter randomized controlled trial.

INTRODUCTION: The concept of anatomic restoration has garnered considerable interest in the form of kinematically aligned total knee arthroplasty (KA-TKA). KA-TKAs have been reported to reproduce natural alignment and kinematics. However, few randomized controlled trials (RCTs) have compared the biomechanical outcomes and the long-term clinical outcomes of KA-TKA with those of mechanically aligned TKA (MA-TKA). We aim to investigate the long-term clinical and biomechanical effects of KA-TKA and to determine whether KA-TKA or MA-TKA is more appropriate for primary TKA. METHODS: This trial will compare clinical and biomechanical outcomes of KA-TKA to those of MA-TKA. Two hundred patients will be enrolled in the RCT and randomized into KA-TKA or MA-TKA groups. Both the groups will be evaluated 1 week before the operation, on the day of the operation, 6 months after the operation, and 1, 5, and 10 years after the operation. The primary outcome is the difference between preoperative and 1-year postoperative functional activity scores of the 2011 Knee Society Score (2011 KSS) in both groups as well as the differences between the scores of both groups. The secondary outcomes will include differences in symptom, satisfaction, and expectation scores of the 2011 KSS, intraoperative kinematics evaluation, postoperative clinical outcomes and complications, pre- and postoperative gait analyses and radiograph evaluations between both KA-TKA and MA-TKA.

MRI-determined preoperative lateral meniscus degeneration is not associated with adverse mid-term clinical results after mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: One of the conditions constituting surgical indication for medial mobile-bearing unicompartmental knee arthroplasty (UKA) is that there is full-thickness cartilage in the lateral compartment under valgus stress radiography. However, it is unclear whether medial unicompartmental knee arthroplasty should be performed if there is degeneration of the lateral meniscus on preoperative magnetic resonance imaging (MRI). METHODS: The records of 77 patients (77 knees) who underwent Oxford mobile-bearing UKA were retrospectively reviewed. Based on the status of the lateral meniscus in each knee using preoperative MRI with Stoller's classification system, the patients were divided into two groups; a normal group and a lateral meniscus degenerated group (grades 1-3). The preoperative personal data and the outcome data three years postoperatively were compared. RESULTS: The normal group contained 31 knees while the lateral meniscus degenerated group comprised 46 knees. There was no difference in clinical outcome or knee function between the groups at three years after UKA. There was no difference in re-operation and revision rate between the groups with no revisions in either group. CONCLUSIONS: It may not be necessary to exclude UKA indications for cases with degenerative findings in the lateral meniscus on preoperative MRI.

Is postoperative flexion angle genuinely better in unicompartmental knee arthroplasty than in total knee arthroplasty? A comparison between the knees in the same patients.

BACKGROUND: The aim of this retrospective study was to clarify if unicompartmental knee arthroplasty (UKA) can acquire a greater postoperative flexion angle than total knee arthroplasty (TKA) in the same individuals after adjusting for the preoperative flexion angle and if the preoperative flexion angle correlates with the change in flexion postoperatively. METHODS: Thirty-five patients between 2011 and 2017 who had undergone simultaneous TKA on one knee and UKA on the other knee were included in the study. Range of motion was measured preoperatively and at one year after the surgery. The relationship between the pre- and postoperative flexion angles was evaluated. RESULTS: UKA can acquire approximately 10° greater flexion postoperatively when compared to TKA, even after adjustment for the preoperative flexion angle. The preoperative flexion angle is strongly and negatively correlated with the change in flexion angle in both the TKA and UKA knees. A preoperative knee with a smaller flexion angle will gain greater flexion postoperatively, whereas a preoperative knee with a greater flexion angle tends to lose flexion angle. The thresholds of gain/loss are estimated as 123° and 135° in TKA and UKA knees, respectively. CONCLUSIONS: These results provide an evidence that the UKA can acquire a greater postoperative flexion angle than the TKA and valuable information for patients who demand a deep postoperative flexion angle.

A Modified Under-Vastus Approach for Knee Arthroplasty with Anatomical Repair of Soft Tissue.

The under-vastus approach (UVA) is a modification of the conventional subvastus approach for knee arthroplasty. Our modified UVA allows the muscles to be spared while offering good exposure of the operative field and facilitating anatomical repair of the capsule and fascia. A medial parapatellar incision is made and the vastus medialis fascia is incised along the same line. The muscle belly is not incised but detached from the surrounding fascia and retracted laterally. The suprapatellar pouch capsule is then laterally incised under the vastus muscles. The patella can then be easily retracted laterally and adequate exposure is possible. After the procedure, both capsule and fascia can be anatomically repaired. We use this approach for all primary arthroplasties in our practice. There has been no case in which an additional muscle incision was required, and there were no intraoperative complications. The modified UVA allows for excellent exposure of the operative field as well as muscle retention in both primary total and unicompartmental knee arthroplasties.