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Abstract The level of dynamic mechanical instability between the bony parts of the ankle joint provides important information on biomechanical function. However, the dynamics of the distance between the talus and lateral malleolus during gait remain unclear. This study aimed to compare the distance between the talus and lateral malleolus and the ankle joint angles during the stance phase of gait between individuals with chronic ankle instability (CAI) and healthy adults. The comparison was conducted using a synchronized ultrasound (US) imaging with a three-dimensional motion analysis (MA) system. This cross-sectional study included 12 participants (5 males, 7 females; age, 20.5 ± 1.8 years; height, 166.6 ± 9.4 cm; body weight, 60.2 ± 5.3 kg; body mass index, 21.7 ± 2.0 kg/m2; 16 feet) with CAI and 10 healthy controls (4 males, 6 females; age, 21.2 ± 1.6 years; height, 164.6 ± 10.5 cm; body weight, 56.8 ± 11.3 kg; body mass index, 20.8 ± 2.6 kg/m2; 20 feet). The distance between the talus and lateral malleolus during gait was significantly increased in the CAI group compared with that in the control group throughout the stance phase. The ankle dorsiflexion angle was smaller in the CAI group during the middle and terminal stance phases. Additionally, the ankle inversion angle was greater in the CAI group than in the control group. Our findings show the application of the synchronized US and MA system in the assessment of mechanical instability in CAI group, which may be used to determine treatment efficacy.

Category: Ankle Introduction/Purpose: The primary aim of the present study is to assess the clinical success rate of fixation for osteochondral lesions of the talus (OLT). The secondary outcomes concern the union rate and adverse events. Methods: A systematic literature search of PubMed, Embase (Ovid), and Cochrane Library was performed up to December 2023. The primary outcome was the pooled clinical success rate following fixation with 95% confidence interval (95%-CI). Secondary outcomes concerned the union rate, complication rate, and revision rate. Results: A total of 10 studies with 241 ankles were included at a mean follow-up of 40 months. The pooled clinical success rate was 92% [95%-CI: 87% – 95%]. The pooled union rate was 91% [95%-CI: 87% - 94%]. A sub-analysis found superior success rate for patients treated with bone-peg (98% [95%-CI: 89 – 100] compared to non-metal screw and pin (84% [95%-CI: 68 – 93]), P=0.03. The pooled complication and revision rate were 1% [95%-CI: 0 - 4] and 6% [95%-CI: 0 - 4], respectively. Conclusion: Fixation for osteochondral lesions of the talus leads to successful clinical outcomes in 9 out of 10 patients. Moreover, fragment union is achieved in 9 out of 10 cases, with a low reported complication rate. These findings show that when a symptomatic OLT is fixable physicians should always consider fixation.

Abstract Background Limited healing potential of the meniscus remains a burden for the successful repair of meniscus injuries in the orthopaedic fields. Silk-elastin (SE) is a novel recombinant protein with favorable properties for wound healing. This proof-of-concept study aimed to investigate the therapeutic effect of silk-elastin in a rabbit meniscal defect model. Methods A migration assay using rabbit meniscus and synovial cells with various concentrations of SE in a culture medium was conducted to investigate the mechanism of meniscal healing by SE. Additionally, cylindrical defects with a 1.5 mm diameter were created at the anterior horn of the medial meniscus of rabbits. The animals were divided into three groups: 1) the Blank group; defect only, 2) the Col I group; implantation of type I atelocollagen sponge, and 3) the SE group; implantation of SE (150 mg/ml) sponge. Whole medial menisci were harvested at 4, 8, 12, and 24 weeks after surgery. Histological analyses including immunohistochemical staining were performed to assess meniscal healing. Results In vitro study, Migration assay demonstrated a significantly higher number of migrated cells only in synovial cells. Especially, the SE concentration of 10 µg/mL demonstrated the highest number of migrated cells compared with other concentrations. In vivo study, the SE group exhibited significantly higher Ishida scores than other groups at all time points. Furthermore, the SE group showed higher synovial coverage scores than the Col I group at 4 and 8 weeks. Immunohistochemical staining demonstrated higher type II collagen staining in the SE group compared to other groups at 12 weeks. Implanted SE was efficiently replaced by safranin-O staining positive tissue within 8 weeks. Conclusions SE could effectively repair a meniscal defect by inducing coverage of synovial cells. SE has the potential to be a useful material for meniscal repair.

Abstract Suppressing inflammation and abnormal subchondral bone turnover is essential for reducing osteoarthritis (OA) progression and pain relief. This study focused on calcitonin gene-related peptide (CGRP), which is involved in inflammation and bone metabolism, and investigated whether a CGRP receptor antagonist (rimegepant) could suppress OA progression and relieve pain in two OA models. C57BL/6 mice (10-week-old) underwent surgical destabilization of the medial meniscus, and Rimegepant (1.0 mg/kg/100 μL) or phosphate-buffered saline (100 μL) was administered weekly intraperitoneally after OA surgery and evaluated at 4, 8, and 12 weeks. In the senescence-accelerated mice (SAM)-prone 8 (SAMP8), rimegepant was administered weekly before and after subchondral bone sclerosis and sacrificed at 9 and 23 weeks, respectively. Behavioral assessment and immunohistochemical staining (CGRP) of the dorsal root ganglion (DRG) were conducted to assess pain. In DMM mice, synovitis, cartilage degeneration, and osteosclerosis were significantly suppressed in the rimegepant group. In SAMP8, synovitis, cartilage degeneration, and osteosclerosis were significantly suppressed by rimegepant at 9 weeks; however, not at 23 weeks. Behavioral assessment shows the traveled distance and the number of standings in the rimegepant group were significantly longer and higher. In addition, CGRP expression of the DRG was significantly lower in the rimegepant group at 8 and 12 weeks of DMM and 9 weeks of SAMP8 treatment. No adverse effects were observed in either of the mouse models. Inhibition of CGRP signaling has the potential to be a therapeutic target to prevent OA progression and suppress pain through the attenuation of subchondral bone sclerosis and synovitis.

Abstract Background Animal models of spontaneous osteoarthritis (OA) are sparse and not well characterized. The purpose of the present study is to examine OA-related changes and mechanisms in senescence-accelerated mouse prone 8 (SAMP8) that displays a phenotype of accelerated aging. Methods Knees of male SAMP8 and SAM-resistant 1 (SAMR1) mice as control from 6 to 33 weeks of age were evaluated by histological grading systems for joint tissues (cartilage, meniscus, synovium, and subchondral bone), and µCT analysis. Gene expression patterns in articular cartilage were analyzed by real-time PCR. Immunohistochemistry was performed for OA-related factors, senescence markers, and apoptosis. Results Starting at 14 weeks of age, SAMP8 exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. From 18 to 33 weeks of age, SAMP8 progressed to partial or full-thickness defects with exposure of subchondral bone on the medial tibia and exhibited synovitis. Histological scoring indicated significantly more severe OA in SAMP8 compared with SAMR1 from 14 weeks [median (interquartile range): SAMR1: 0.89 (0.56–1.81) vs SAMP8: 1.78 (1.35–4.62)] to 33 weeks of age [SAMR1: 1.67 (1.61–1.04) vs SAMP8: 13.03 (12.26–13.57)]. Subchondral bone sclerosis in the medial tibia, bone mineral density (BMD) loss of femoral metaphysis, and meniscus degeneration occurred much earlier than the onset of cartilage degeneration in SAMP8 at 14 weeks of age. Conclusions SAMP8 are a spontaneous OA model that is useful for investigating the pathogenesis of primary OA and evaluating therapeutic interventions.

Abstract Background Hypermobility of the first tarsometatarsal (TMT) joint is frequently identified in patients with hallux valgus (HV); however, its association with the development of osteoarthritis in the first TMT joint in such patients remains unknown. The purpose of this study was to clarify the distribution of subchondral bone density of the first TMT joint via computed tomography (CT) using Hounsfield units (HU). Methods Patients were divided into three groups: the osteotomy (20 feet; 20 women, mean age: 61.8 years), arthrodesis (23 feet; two men, 21 women, 71.2 years), and control group (patients without HV deformity who had undergone CT scans of the foot; 13 feet; seven men, six women, 29.7 years). The HU ratios were calculated, which were defined as the HU value of each subdivision of the subarticular spongiosa of the first TMT joint [dorsomedial (DM), dorsolateral (DL), plantomedial (PM), and plantolateral (PL)] divided by the HU values of the entire joint surface. The ratios for the osteotomy, arthrodesis, and control groups were compared. The degradation of the articular cartilage in the first TMT joint was histologically graded in the arthrodesis group. Tukey–Kramer multiple comparison analysis was conducted to compare the HU ratios among the three groups, and the histological grade in each subdivision. Results The arthrodesis group demonstrated high HU ratios in the DM area of the medial cuneiform, and significantly lower HU ratios in the PL area of the first metatarsal. Lower HU ratios in the DL area were observed in both the osteotomy and the arthrodesis group when compared to that in the medial cuneiform of the control group. The histological evaluation indicated nearly normal articular cartilage for all subdivided areas in both the medial cuneiform and the first metatarsal in patients with severe HV. Conclusions Although high subchondral bone density was identified in the DM area of the medial cuneiform in severe HV, only mild degradation was histologically observed in the articular cartilage of the first TMT joint. Our findings suggest that the indications for arthrodesis of the first TMT should be reconsidered based on the severity of the degenerative changes in the first TMT joint.

Abstract We determined how the in vivo mobility of the first tarsometatarsal (TMT) joint can be quantified during gait. Twenty-five healthy participants (12 females) with no history of foot disorders were included. Non-invasive ultrasound (US) with a three-dimensional motion analysis (MA) system was used to evaluate the kinematic characteristics of first TMT joint during stance phase of gait. US probe was positioned longitudinally above the first TMT joint and adjusted to its proximal dorsal prominence. Gait analysis was conducted by the MA system starting with the activation of B-mode US video at 80 frames per second and 60-mm depth for simultaneous capture. During stance phase, the first metatarsal was translated dorsally with respect to the medial cuneiform, returning to a neutral level at toe-off in all subjects. During middle stance phase, the medial cuneiform was stable in males but displaced in the plantar direction in females and was the primary contributor to the differences in sagittal mobility observed between groups. Quantitatively measuring sagittal mobility of the first TMT joint could be useful for the early detection of foot abnormalities. The dynamic characteristics of the medial cuneiform during gait in healthy females may be associated with a high prevalence of hallux valgus.

Abstract Background Diminished balance is associated with the incidence of ankle and lower extremity injuries in adolescents. Although flexible flatfoot is a common foot condition in pediatric and adolescent populations, the association between balance control and foot morphology remain unclear in adolescent athletes. Methods Rearfoot angle in the double-limb standing position, body mass index (BMI), and isometric muscle strength related to the knee joint were retrospectively reviewed in 101 adolescent athletes (75 boys and 26 girls) with a mean age of 14.0 years (range 12–17). Postural stability during single-leg standing on static and dynamic platforms was investigated using Balance System SD in 119 feet without functional ankle instability. The participants were divided according to their rearfoot angle into control (less than 7°) and valgus (greater than or equal to 7°) groups. The measured parameters were compared between the control and valgus groups using Welch’s t-test, and P values

Osteoarthritis (OA), the most prevalent aging-related joint disease, is characterized by insufficient extracellular matrix synthesis and articular cartilage degradation and is caused by various risk factors including aging and traumatic injury. Most microRNAs (miRNAs) have been associated with pathogenesis of osteoarthritis (OA) using in vitro models. However, the role of many miRNAs in skeletal development and OA pathogenesis is uncharacterized in vivo using genetically modified mice. Here, we focused on miR-23–27–24 clusters. There are two paralogous miR-23–27–24 clusters: miR-23a-27a-24–2 (miR-23a cluster) and miR-23b-27b-24–1 (miR-23b cluster). Each miR-23a/b, miR-24, and miR-27a/b is thought to function coordinately and complementary to each other, and the role of each miR-23a/b, miR-24, and miR-27a/b in OA pathogenesis is still controversial. MiR-23a/b clusters are highly expressed in chondrocytes and the present study examined their role in OA. We analyzed miRNA expression in chondrocytes and investigated cartilage-specific miR-23a/b clusters knockout (Col2a1-Cre; miR-23a/bflox/flox: Cart-miR-23clus KO) mice and global miR-23a/b clusters knockout (CAG-Cre; miR-23a/bflox/flox: Glob-miR-23clus KO) mice. Knees of Cart- and Glob-miR-23a/b clusters KO mice were evaluated by histological grading systems for knee joint tissues using aging model (12 and/or 18 month-old) and surgically-induced OA model. miR-23a/b clusters were among the most highly expressed miRNAs in chondrocytes. Skeletal development of Cart- and Glob-miR-23clus KO mice was grossly normal although Glob-miR-23clus KO had reduced body weight, adipose tissue and bone density. In the aging model and surgically-induced OA model, Cart- and Glob-miR-23clus KO mice exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. However, the histological scores were not significantly different in terms of the severity of OA in Cart- and Glob-miR-23clus KO mice compared with control mice. Together, miR-23a/b clusters, composed of miR-23a/b, miR-24, miR-27a/b do not significantly contribute to OA pathogenesis.

Aims: Meniscal injuries are common and often induce knee pain requiring surgical intervention. To develop effective strategies for meniscus regeneration, we hypothesized that a minced meniscus embedded in an atelocollagen gel, a firm gel-like material, may enhance meniscus regeneration through cell migration and proliferation in the gel. Hence, the objective of this study was to investigate cell migration and proliferation in atelocollagen gels seeded with autologous meniscus fragments in vitro and examine the therapeutic potential of this combination in an in vivo rabbit model of massive meniscus defect. Methods: A total of 34 Japanese white rabbits (divided into defect and atelocollagen groups) were used to produce the massive meniscus defect model through a medial patellar approach. Cell migration and proliferation were evaluated using immunohistochemistry. Furthermore, histological evaluation of the sections was performed, and a modified Pauli’s scoring system was used for the quantitative evaluation of the regenerated meniscus. Results: In vitro immunohistochemistry revealed that the meniscus cells migrated from the minced meniscus and proliferated in the gel. Furthermore, histological analysis suggested that the minced meniscus embedded in the atelocollagen gel produced tissue resembling the native meniscus in vivo. The minced meniscus group also had a higher Pauli’s score compared to the defect and atelocollagen groups. Conclusion: Our data show that cells in minced meniscus can proliferate, and that implantation of the minced meniscus within atelocollagen induces meniscus regeneration, thus suggesting a novel therapeutic alternative for meniscus tears.

Background: The posterior cruciate ligament (PCL) is one of the essential stabilizers of the knee joint and it was demonstrated that its degenerative change related to the knee osteoarthritis (OA). We aimed to evaluate signal of the PCL in OA patients in comparison with healthy young and elderly volunteers using the ultra-short echo timeenhanced (UTE)-T2∗ mapping, and to validate these findings with histology. Methods: Thirty asymptomatic volunteers, 13 young people (younger group) and 17 elderly people (elder group), and 27 patients who had undergone total knee arthroplasty (OA group) were enrolled in this study. UTE-T2∗ maps of PCL were obtained from all participants. The PCL was divided into proximal, middle, and distal parts and the UTET2∗ values obtained from each part were compared among the groups. In OA group, the sacrificed PCLs were evaluated histologically in each part corresponding to the part of UTE-T2∗ maps and compared. Results: The UTE-T2∗ values in OA group were significantly higher than those in other groups except in distal part. In elder group, the UTE-T2∗ values were significantly higher than those in younger group only in the proximal part. Moreover, in OA group, the UTE-T2∗ values in proximal and middle parts were significantly higher than those in distal part. There was a moderate correlation between the UTE-T2∗ values and histological scores. Conclusions: The specific signal intensity pattern of the PCL in patients with OA was demonstrated using UTE-T2∗ mapping, and these findings were related to histological degenerated status of the PCL.

Abstract Background Posterior cruciate ligament (PCL) degeneration is often seen in knee osteoarthritis (OA); however, there is no established method for its evaluation. The purpose of this study is to investigate whether the Hounsfield unit (HU) using computed tomography (CT) could be a useful scale to evaluate the degeneration of PCL in knee OA. Methods Knee OA treated with total knee arthroplasty (21 patients, 21 knees) and non-osteoarthritic knees (21 patients, 21 knees) were retrospectively observed and studied. All PCLs in the knees were analyzed using CT. The PCL in the sagittal section was divided into three regions: proximal, middle, and distal sections. The HU value of the PCL at each area was measured. In osteoarthritic knees, tissues from the PCL were collected and histologically graded. The correlation between the radiological classification by Kellgren and Lawrence and the histological grade was analyzed. The average CT HU values for each degenerative grade were also calculated and compared. Results The HU values in OA and non-OA were 70.7 and 88.4 HU (p 0.05) in the distal region, respectively. The degeneration of PCL was graded as follows: one, three, and 17 mild, moderate, and severe cases at the proximal portion, and 16, 4, and one mild, moderate, and severe cases at the distal portion, respectively. The radiological classification and the grade of degeneration were not correlated in either the proximal (r = 0.047, p = 0.84) or the distal (r = − 0.21, p = 0.35) portions. The HU value was 84.5, 72.1, and 70.6 HU for mild, moderate, and severe grades, respectively (mild versus moderate: p 0.05). Conclusions In knee OA, a lower HU value in the PCL indicates the progression of degeneration. The CT HU value could be a useful measurement to predict the grade of PCL degeneration.

Tendon is a fibrous connective tissue, that is, transmitting the forces that permit body movement. However, tendon/ligament biology is still not fully understood and especially, the role of miRNAs in tendon/ligament is sparse and uncharacterized in in vivo models. The objectives of this study were to address the function of DICER using mice with tendon/ligament-specific deletion of Dicer (Dicer conditional knockout; cKO), and to identify key miRNAs in tendon/ligament. Dicer cKO mice exhibited hypoplastic tendons through structurally abnormal collagen fibrils with downregulation of tendon-related genes. The fragility of tendon did not significantly affect the tensile strength of tendon in Dicer cKO mice, but they showed larger dorsiflexion angle in gait compared with Control mice. We identified two miRNAs, miR-135a and miR-1247, which were highly expressed in the Achilles tendon of Control mice and were downregulated in the Achilles tendon of Dicer cKO mice compared with Control mice. miR-135a mimic increased the expression of tendon-related genes in injured Achilles tendon-derived fibroblasts. In this study, Dicer cKO mice exhibited immature tendons in which collagen fibrils have small diameter with the downregulation of tendon-related genes such as transcriptional factor, extracellular matrix, and miRNAs. Thus, DICER plays an important role in tendon maturation, and miR-135a may have the potential to become key miRNA for tendon maturation and healing.

Background/objective: There is controversy regarding the biomechanical function of the anteromedial (AM) and posterolateral (PL) bundles in isolated tibiofemoral rotation during double-bundle anterior cruciate ligament (ACL) reconstruction. This study aimed to evaluate the biomechanical function of the AM and PL bundles of the ACL using a computer navigation system. Methods: This study involved 15 patients who underwent double-bundle ACL reconstruction. Anteroposterior and isolated rotational knee laxity were measured with a navigation system. The measurements were performed four times, namely, before fixation, after temporary PL bundle fixation, after AM bundle fixation, and after double-bundle reconstruction. With knee flexion ranging from 20° to 60°, we continuously measured the anterior tibial displacement under an anterior drawer stress (100 N using a spring balance). The total range of tibial rotation was also measured under an external and internal rotational torque of 3 Nm. Results: Fixation of either the AM or the PL bundle significantly reduced the anteroposterior displacement at all knee flexion angles. Although the anteroposterior displacement after AM bundle fixation was relatively similar throughout the range of motion (2.4–3.2 mm), the anteroposterior displacement after PL bundle fixation increased continuously with knee flexion (2.2–4.6 mm). With respect to the total range of tibial rotation under external and internal rotational torque, there was no significant difference between AM and PL bundle fixation throughout the range of motion. The total range of tibial rotation was significantly reduced only on double-bundle reconstruction at 20° and 25° knee flexion compared to the pre-reconstruction range (P = 0.015 and 0.036, respectively). Conclusion: The AM and PL bundles function differently for controlling anterior knee laxity throughout the range of motion. The function of the AM and PL bundles was similar for controlling isolated tibiofemoral rotation. Isolated tibiofemoral rotation was significantly controlled only on double-bundle reconstruction at knee flexion angles of 20° and 25°. Keywords: Anterior cruciate ligament, Double-bundle, Navigation system, Intraoperative kinematics, Isolated tibiofemoral rotation

Iatrogenic hallux varus is a difficult complication of hallux valgus surgery. Although tendon transfer combined with bony correction is performed for hallux varus, tendon transfer has several disadvantages, such as the complicated nature of the procedure and the donor site morbidity. We describe the case of a 70-year-old woman with iatrogenic hallux varus treated by lateral collateral ligament (LCL) reconstruction using a suture tape anchor with bony correction. Tarsometatarsal joint arthrodesis was performed to correct the narrow intermetatarsal angle (IMA), and the varus deformity of the great toe at the metatarsophalangeal joint was corrected by anatomical reconstruction of the LCL using the suture tape anchor. One year postoperatively, the Japanese Society for Surgery of the Foot Hallux Metatarsophalangeal-Interphalangeal Scale had improved from 37 to 90 points. Radiography confirmed that the hallux valgus angle had been corrected from -24° to 4° and the IMA from 0° to 8°. Reconstruction of the LCL using suture tape anchor is an easy procedure for iatrogenic hallux varus which can achieve good stabilization.

Category: Ankle; Other Introduction/Purpose: Chronic lateral ankle instability (CLAI) that is developed after multiple lateral ankle ligament injury lead to ankle osteoarthritis. Although isolated deltoid ligament injury is rare compared to lateral ankle ligament injury, deltoid ligament tear, especially deep posterior tibiotalar ligament (PTT) can be observed arthroscopically in CLAI patients. Unphysiological loading of the ankle joint with CLAI might cause degradation of the deltoid ligament. This study aimed to investigate image findings of the deltoid ligament using computed tomography (CT) value for quantitative analysis of degenerative ligament changes in CLAI patients. Methods: Among the enrolled patients who underwent ankle magnetic resonance imaging (MRI) and CT scans of the ankle, this retrospective analysis included 24 ankles without ankle osteoarthritis, osteochondral lesion of the talus (OLT), flatfoot and ankle fractures (14 males and 10 females; mean age, 42.8 years) as a control group, and 14 CLAI ankles without OLT (7 males and 7 females; mean age, 31.1 years) as CLAI group. The CT scans were performed using a 64-slice multidetector row CT. Deep PTT was detected on coronal T2-weighted MR images. Both the coronal MR and CT images were matched for analysis, then average CT values were measured using the region of interest that was applied to the detected area of deep PTT on the CT images. Spearman’s correlation coefficient was used to evaluate the correlation between age and CT value in the control group. Results: The strong negative correlation was identified between age and CT value in the control group (Spearman ρ= -0.88; p < 0.001). The CT value of the deep PTT are degraded with aging. Mean CT value of deep PTT in participants under 60 years old were 79.9 HU (95% CI, 75.1-84.8) in the control group (18 ankles), and 66.5 HU (95% CI, 58.6-74.5) in the CLAI group (14 ankles) (Welch’s t test; p = 0.005). Conclusion: MRI techniques and protocols recently have been developed, however, some limitations remain such as a quantitative evaluation of the ligament. Our findings suggest that the CLAI can lead to degradation of the deltoid ligament via an overloading of medial ankle structures. Additionally, CT values should be useful for quantitatively evaluating ligament status including degenerative changes.

Background: Retrograde drilling (RD) is generally used for treating osteochondral lesion of the talus (OLT) with a stable osteochondral fragment and nearly normal articular cartilage surface. Previous studies that included participants of various ages have reported good clinical results. This study aimed to clarify the clinical outcomes of RD for OLT in juvenile patients whose bone-forming ability and physical activity might affect the healing process. Methods: This retrospective study included 8 juvenile patients who underwent RD for OLT (5 boys and 3 girls, mean age 14.9 years, mean follow-up 2 years, 7 medial and 1 central lesion). American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score and ankle activity score were evaluated, and arthroscopic findings were graded according to the International Cartilage Research Society (ICRS) classification system. The condition of the underlying bone was assessed on preoperative computed tomographic images. The stability, incorporation, and subsidence of the osteochondral fragment, articular surface congruity, and the area of the bone marrow lesion (BML) were evaluated using magnetic resonance imaging (MRI). Results: AOFAS ankle-hindfoot score and ankle activity score significantly improved postoperatively. Arthroscopically, the lesions were classified as ICRS grade 0 or 1. Bone sclerosis or multiple small cysts of the underlying bone were observed in all patients. MRI demonstrated no signs of osteochondral fragment instability or subsidence, good or fair fragment incorporation, good articular surface congruity, or slight irregularity. The postoperative BML was reduced; however, these BMLs were still detectable at 1 year after surgery. Conclusion: Our data suggested that RD is an option for treating juvenile patients with OLT refractory to nonoperative treatment at short-term follow-up. Although bone sclerosis or multiple small cysts were identified in the underlying bone preoperatively and the BML under the osteochondral fragment remained postoperatively, clinical status such as pain and physical activity level were improved by RD. Level of Evidence: Level IV, retrospective case series.

Category: Ankle Introduction/Purpose: Osteochondral lesion of the talus (OLT) has various treatment options which are chosen depending on the stage, size and cartilage condition. The fixation technique can restore the natural congruency with the hyaline cartilage. However, it is not clear whether a bone condition such as the disruption of the subchondral bone plate will affect the clinical results after the fixation of the osteochondral fragment. We hypothesized that even if the subchondral bone plate were disrupted, if the articular cartilage condition in the osteochondral fragment were good, then the clinical results of the fixation technique would be good. The aim of this study was to explore whether the fragment’s bone condition affects clinical outcomes including second look arthroscopy. Methods: Eighteen ankles in 17 patients, which had undergone the fixation technique using poly-L-lactide (PLLA) pins, were included. The mean follow-up period was 18.8±8.9 months. They consisted of 10 males and 7 females, with a mean age of 20.1±10.1 years. Based on the fragment’s bone condition on preoperative CT, ankles were divided into 3 groups; normal, segmentation, and absorption groups. The American Orthopaedic Foot & Ankle Society (AOFAS) score were evaluated both pre and post surgery. On MRI, the BME area was measured, and stability, incorporation, subsidence, and the surface of the articular cartilage of the fragment were evaluated. Second look arthroscopic findings were evaluated in 13 ankles. The repair of OLT was assessed according to the criteria of the ICRS which are allocated for the degree of filling defect by repair tissue, integration, and surface appearance of the repair site. Results: The AOFAS score before surgery significantly improved from 72.1±2.8 points to 98.6±3.3 points at the final follow-up in all ankles. In each group, the AOFAS score improved and there were no significant differences in AOFAS score among the 3 groups at final follow-up. MRI at 1 year showed good incorporation and cartilage surface in all groups, but the bone marrow lesion in the absorption group was significantly larger than that in the other groups. In the second look arthroscopic findings, the ICRS scale for the normal, segmentation, and absorption groups produced 10.6±1.7 points, 9.8±1.9 points, and 10.7±1.2 points, respectively. Conclusion: Good clinical results including those of second look arthroscopy for osteochondral fragment fixation using PLLA pins in OLT were obtained, even in the case of disruption of the subchondral bone plate. Since the fixation procedure can restore the native contour of the articular cartilage surface, this surgical procedure is a viable option for large OLT lesions regardless of bone condition in the osteochondral fragment.

Category: Ankle, Basic Sciences/Biologics Introduction/Purpose: Usefulness of ultrasonographic guided saphenous nerve block is well known for perioperative pain management of foot and ankle surgery. However, in some cases it may be impossible to identify the saphenous nerve, especially women or obese patients, so successful rate of ultrasonographic guided saphenous nerve block was reported 70 to 80%. Previous reports demonstrated that the saphenous nerve is running adjacent to the greater saphenous vein, which suggests that the greater saphenous vein can be an indicator to identify the saphenous nerve. The purpose of this study was to examine anatomical relationship between the saphenous nerve and the greater saphenous vein which is depicted using the near-infrared (NIR) vascular imaging system, the Vein Viewer Flex®. Methods: Thirty legs as 15 healthy subjects (13 males, 2 females) were included in this study. Average age was 34.2 ± 3.2 years old. In a supine position, the knee joint was flexed 60 degrees with mild flexion, abduction, and external rotation of the hip joint, and the greater saphenous vein was depicted using the Vein Viewer Flex® on the skin of the lower extremity. The vein visualized as a green light was then marked using the skin marker. (Figure 1). After marking the greater saphenous vein, the greater saphenous vein and saphenous nerve were identified under ultrasonography at 5 cm distal from the medial knee joint space (Figure 2). The distance between the greater saphenous vein which was marked using the Vein Viewer Flex® and the saphenous nerve was measured in the ultrasonography images. The circumference of the leg (COL) was also measured. Results: The course of the greater saphenous vein could be depicted by the Vein Viewer Flex® in all cases, and it was confirmed by ultrasonography. It was confirmed that the saphenous nerve was located under the sartorius fascia and it was running posteromedially in parallel of the greater saphenous vein. The mean distance from the saphenous nerve and the greater saphenous vein was 7.9 ± 2.7 mm. There was no significant difference between left and right legs (right: 7.9±2.8 mm, left: 8.0±3.0 mm, P=0.95). The mean COL was 34.2 ± 1.9 mm, and there was a moderate positive correlation (r = 0.45). Conclusion: This study revealed that the saphenous nerve is running in parallel of the greater saphenous vein which can be depicted by the Vein Viewer Flex®. Ultrasonography after depicting greater saphenous vein enabled to confirm the saphenous nerve with certainly and noninvasive. These findings suggested that the combination of the Vein Viewer Flex® and ultrasonography enables the saphenous nerve block to be more reliable procedure even the saphenous nerve is hardly identified by the ultrasonography.

Category: Ankle, Arthroscopy, Basic Sciences/Biologics Introduction/Purpose: Several surgical options are available for the treatment of osteochondral lesion of the talus (OLT). Fixation of the osteochondral fragment could be performed for large lesions with the remaining articular cartilage surface of OLT. Bioabsorbable bone fixation devices, especially those made of poly-L-lactic acid (PLLA), can be used for fixation of the osteochondral fragment. Postoperative osteolysis surrounding the PLLA pins is occasionally observed; however, the significance and details of the event are not fully understood. This study aimed to elucidate the association among osteolysis surrounding the PLLA pins, histopathological findings of OLT, and preoperative computed tomography (CT) values of the pin fixation sites. Methods: This retrospective analysis included 20 patients with OLT (12 males and 8 females; mean age, 21.8 years). The tissue of the osteochondral fragment was intraoperatively collected using a bone biopsy needle. Subsequently, fixation of the osteochondral fragment was performed through the biopsy hole using a PLLA pin. Osteolysis surrounding the PLLA pin was assessed postoperatively by magnetic resonance (MR) imaging. The patients were then divided into an osteolysis and non-osteolysis group. Histopathologically, 5 parameters (trabecular bone loss, empty lacunae, inflammatory granulation tissue, cartilage like tissue, and osteoclast) were assigned scores of 1–3 points (negative, mild, and severe). The score was calculated as minimal (5 points) or maximal (15 points) via hematoxylin and eosin staining. The CT values around the pin insertion site on the postoperative MR images were measured using the region of interest on the preoperative CT images. The average values were calculated from consecutive 3 images. Results: Postoperative osteolysis and non-osteolysis surrounding the PLLA pin were observed in 9 and 11 patients, with a mean age of 22.8 and 21.0 years and a mean number of PLLA pins of 2.7 and 2.4, respectively. No significant differences were found between the two groups. Histopathological evaluation revealed that the osteolysis group had a significantly higher pathological score of 10.1 (SD, 2.0) than the non-osteolysis group, which had a score of 6.1 (SD, 1.0; P=0.0003). Preoperative CT images of the osteolysis and non-osteolysis groups showed mean CT values of 364.3 HU (SD, 78.0) and 463.6 HU (SD, 133.5) (p=0.054), respectively, on the coronal images, and 339.2 HU (SD, 64.2) and 467.8 HU (SD, 109.9) (p=0.0049), respectively, on the sagittal images. Conclusion: Intraoperative biopsy of the OLT allowed for histopathological evaluation in the same location as the site of PLLA pin fixation. Our findings suggest that the preoperative environments of the cancellous bone under the OLT affect osteolysis surrounding the PLLA pin postoperatively. Additionally, low preoperative CT values under OLT can assist in the prediction of osteolysis surrounding the PLLA pin, and another fixation method, such as a bone peg, should be considered for the fixation of the osteochondral fragment in these patients.

Category: Ankle, Arthroscopy Introduction/Purpose: Osteochondral lesion of the talar dome (OLT) is common condition that causes pain of ankle joint in juvenile patients. Several surgical options have been available such as excision of detached cartilage fragment, microfracture, autologous cancellous bone graft and osteochondral autografting depending on the status of OLT. Arthroscopic drilling including transmalleolar or retrograde technique could be a good option for OLT patients with stable osteochondral fragment with normal articular surface. Retrograde drilling has an advantage in preventing the iatrogenic articular cartilage injury. This study aimed to clarify the clinical outcome of the retrograde drilling for OLT in juvenile patients. Methods: Our retrospective analysis included 8 patients who underwent retrograde drilling for OLT, in 5 boys and 3 girls, with a mean age of 14.9 years (range, 11-19). Range of motion (ROM) and American Orthopaedic Foot & Ankle Society (AOFAS) ankle- hindfoot score were evaluated as the clinical outcomes. OLTs were classified into 4 grades according to arthroscopic findings by international cartilage research society (ICRS) classification. Radiographic analysis was performed using preoperative and postoperative images. Growth plate was evaluated on plane radiographs, and the location and size of OLT were assessed on computed tomography. The high intensity area of the talus was also measured on T2 fat suppression images. Results: All 8 patients were followed with a mean follow-up period of 2 years, and they had no complication or revision surgery. The mean total ROM were 65.6° preoperatively and 67.1° postoperatively. AOFAS scale improved from 69.3 to 96.7 (p = 0.012). The ICRS 1 and 2 OLT lesions were identified arthroscopically in 5 and 3 patients, respectively. Growth plate remained open in 4 patients, and OLTs were located on the posteromedial in 7 patients, center in 1 patient. The mean size of OLT fragment was 9.8 mm, 6.8 mm and 3.5 mm in length, width and height. Coronal and sagittal T2 fat suppression images demonstrated that the high intensity area of 241.3 mm2, 554.5 mm2 at preoperative status and 190.9 mm2, 302.6 mm2 at final follow-up status. Conclusion: These findings revealed that the retrograde drilling remarkably improved clinical status in juvenile OLT patients. The high intensity area at the talus remained postoperatively, however, that did not affect clinical results. Retrograde drilling procedure should be considered for treating juvenile patients in the early period after detection of the OLT.

Category: Ankle Arthritis, Arthroscopy Introduction/Purpose: Ankle trauma is highly implicated in the etiology of osteoarthritis (OA) of the ankle, and posttraumatic ankle OA is often observed in younger patients. In advanced stages, ankle arthrodesis has been considered as a gold standard treatment, and total ankle arthroplasty is also developed over the past decade for older patients. However, the surgical treatment of severe ankle OA for younger, active patients remains challenging. Ankle distraction arthroplasty is an alternative option for treatment of severe ankle OA in younger patients. The distraction device enables joint distraction with ankle motion that induces cartilage repair of the ankle. This study aimed to clarify the clinical outcome of the ankle distraction arthroplasty with arthroscopic microfracture for ankle OA in younger patients. Methods: This retrospective analysis included 7 ankle OA patients who underwent distraction arthroplasty with arthroscopic microfracture, in 5 men and 2 women, with a mean age of 45.9 years (range, 39-62). Range of motion (ROM) and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score were evaluated as the clinical outcomes. The talotibial joint space was identified as anterior, center and posterior segment on lateral view. The width of joint space in each segment was measured on pre- and post-operative weight-bearing radiographs. The distraction device was removed at 3 months after initial surgery, and second look arthroscopy was also performed at the same time. The arthroscopic findings were assessed retrospectively. Results: All 7 patients were followed with a mean follow-up period of 4.2 years. One patient who had the worst preoperative AOFAS score of 19 converted to arthroscopic ankle arthrodesis at 2 years after the initial surgery. The mean total ROM and AOFAS score improved from 29.3 to 37.1 (p = 0.028), from 41.7 to 76.1 (p = 0.018), respectively. Weight-bearing radiographs showed a width of ankle joint space with anterior, center and posterior of 1.9 mm, 1.8 mm, 2.0 mm at preoperative status and 2.9 mm, 2.8 mm, 2.9 mm at final follow-up status. Second look arthroscopy revealed that the fibrous cartilage like tissue covered the cartilage defect area at the talotibial joint in all patients. Conclusion: Our findings suggest that the distraction arthroplasty with arthroscopic microfracture could be a useful option for active patients with advanced stage of ankle OA. Good clinical status and the width of joint space had been preserved for a maximum of seven years. Further follow-up was required to elucidate the long-term clinical results.

Category: Ankle Introduction/Purpose: Treatment options for osteochondral lesion of the talus (OLT) have substantially increased over the last decade. There are a wide variety of surgical treatments for OLT, and good clinical results have been reported. However, treatment for OLT with large subchondral bone cysts remains under discussion. The combination of autologous bone grafting for subchondral bone cyst with fixation of articular cartilage would be the desirable procedure for the repair of the large subchondral cyst preserving the original cartilage with native structure and geometry. The purpose of this study is to evaluate the clinical outcome of autologous cancellous bone graft and fixation of cartilage fragment for OLT with large subchondral cysts. Methods: Patients comprised seven men and five women, aged 14–70 (mean 35.9) years. All OLTs included full-thickness articular cartilage, extended through subchondral bone and were associated with subchondral cysts. The mean size of the cysts was 9 ×8.6 ×12.3 mm on preoperative CT. Medial lesions were exposed through an oblique medial malleolar osteotomy; lateral lesions through expansion of an anterolateral arthroscopic portal. After refreshed the subchondral cyst, it was grafted with autologous cancellous bone from the distal tibial metaphysis, then cartilage fragments were fixed with nylon suture to surrounding cartilage. Postoperative MRI and CT scans were acquired for all patients at one year after surgery. Seven patients requested screw removal although none had symptoms. The screws were removed and simultaneous arthroscopic examination was performed at 1.5–2 years after surgery with the patients’ permission. The cartilage repair was assessed according to the criteria of the International Cartilage Repair Society (ICRS). Results: Functional outcome was evaluated at 25.3 (15–50) months after surgery. Mean American Orthopedic Foot and Ankle Society ankle-hindfoot outcome score improved from 65.7 to 92 (90–100) postoperatively, with 100% patient satisfaction. All follow-up CT scans showed that the grafts were well consolidated with the surrounding subchondral bone. On MRI one year after surgery, no scans showed any signs of osteochondral graft instability. The mean ICRS arthroscopic score from follow-up arthroscopy was 11.1 (8–12) points, and represented nearly normal cartilage. Conclusion: Our study demonstrated good results of autologous bone grafting in preserving articular cartilage in cases of symptomatic OLT with subchondral cysts. In seven cases, we performed follow-up arthroscopy at 1.5–2 years after primary operation and the chondral fragment showed a smooth surface and good stability. The technique of autologous bone grafting with chondral fragment fixation could be a promising option for treatment of OLT with subchondral cysts.

Category: Ankle Introduction/Purpose: Although chondral or osteochondral injuries are usually assessed by MRI, its accuracy is reportedly low because of the relatively thin cartilage layer and its close apposition to the cartilage talus and tibial plafond. The subchondral bone plays a role in cartilage metabolism, therefore the evaluation of subchondral bone is crucial for cartilage treatment. A method which enables the simultaneous evaluation of cartilage and subchondral bone is useful for the treatment of cartilage injury. The purpose of this study was to assess the feasibility of CT imaging with axial traction for the diagnosis of articular cartilage injuries. Methods: Chondral lesion in 18 ankles of 17 patients were evaluated. These 18 ankles consisted of 11 ankles of osteochondral lesion of the talar dome (OLT), 5 ankles of osteoarthritis of ankle joints and 2 ankles of anterior impingement syndrome. Twelve males and 5 women were included, with a mean age of 33.7 years (range, 15 -70 years). An ankle distractor foot strap was placed on the ankle with 30 degrees flexion of the knee joint, and a traction force of 80 N was applied during CT scanning. Gray scale CT images were allocated colors to make it easier to evaluate the cartilage layer. The international Cartilage Repair Society (ICRS) grades on CT were compared with those in arthroscopic findings. Results: The respective sensitivity and specificity of CT imaging with traction compared to ICRS grading were 74.4%, and 96.3%. The level of agreement of the ICRS grading between CT images and arthroscopic findings showed moderate (kappa coefficient; 0.547). The diagnosis of grade 3 or 4 lesions had 80.0% sensitivity. Axial traction to CT enabled the delineation of the cartilage surface including chondral thinning, defect and cartilage separation more visible (Figure 1). Conclusion: CT with axial traction could obtain acceptable levels of sensitivity and specificity for the evaluation of articular cartilage injuries in addition to the assessment of subchondral bone.

Category: Ankle Introduction/Purpose: Osteochondral lesion of talus (OLT) is treated by several procedures such as bone marrow stimulation technique, cartilage fragment fixation, or autologous osteochondoral bone implantation. The choice of surgical methods depends on the size of lesion and cartilage condition. For unstable small lesion, excision of osteochondral fragment is usually performed. Good clinical results after this procedure is reported, but it is unclear that the morphological repair of subchondral bone and cartilage like tissue at the lesion. The purpose of this study is to evaluate the restoration of subchondral bone and cartilage like tissue after arthroscopic microfracture with excision of osteochondral fragment, and to investigate the clinical outcomes of this operation for the athletes. Methods: From 2005 to 2015, 11 patients (6 men and 5 women) were performed arthroscopic microfracture with excision of osteochondral fragment for OLT. Average age was 28.6 years old (17 - 59 years old). The site of OLT was 10 medial and 1 lateral. The cases of athletes were 7 of 11 cases. The size of preoperative OLT by MRI, measure the depth of the resected site on 3-month postoperative MRI. And we evaluated the appearance of the repair site on 1 year postoperative MRI, clinical outcome using American Orthopaedic Foot and Ankle Society Clinical Rating System (AOFAS), return rate to sports, and period of return to the sports. Results: Preoperative size of lesion on MRI was 9.8 mm in sagittal view, and 6.0 mm in coronal view. Depth of the resected site in 3 months postoperative MRI was 3.1 mm. On one year postoperative MRI, the resected site was filled with cartilage like tissue, and the shape of restored site was good that mimicked the original shape (Figure 1). As for clinical outcome, AOFAS score was 65.4 points preoperatively, and it improved to 93.4 points 1 year postoperatively. In clinical outcomes of the athletes, all cases could return to sports. Average period to return sports was 5.6 months. Only in 1 case, mild pain during sports activity was remained. Preoperative AOFAS score of athletes was 71.4 points and it improved to 98.5 points postoperatively. Conclusion: According to this study, even if a symptom is mild, an early operation will be more likely to result in the early return to sports and good outcomes. In addition, these good outcomes and good congruency on 1 year postoperative MRI suggest that the restored cartilage like tissue is enough for the high activities. The cartilage is repaired with maintaining original shape of talus cartilage. And this method was effective for athletes and was able to get them return to sports with good outcome.

Category: Ankle Introduction/Purpose: Mortise view weight-bearing radiograph is widely used for the diagnosis of osteoarthritis of ankle. Thickness of the articular cartilage cannot be accurately evaluated in the evaluation of joint space from weight-bearing radiograph, because lateral tibiotalar joint space is maintained in valgus type osteoarthritis in some cases. There are few reports on the relation between osteophyte and the articular cartilage injury. We considered that it might be possible to estimate the cartilage injury more accurately by examining osteophytes. The purpose of this study is to analyze the relationship between the location and grade of osteophytes in weight-bearing radiograph and cartilage injury in arthroscopic findings was analyzed. Methods: Twenty-one anklets of 21 patients consisted of 10 males and 10 females, with mean age of 61.4 years (31-79 years), who underwent arthroscopic surgery for osteoarthritis in our department were included. Weight-bearing radiograph were taken before surgery. Location and grade of osteophytes were evaluated using Ankle and Hindfoot Radiographic Osteoarthritis Scoring reported by Kraus et al. Arthroscopic findings were evaluated with International Cartilage Repair Society (ICRS) Grade at a total of 20 sites (9 areas of tibia and talar in tibiotalar joint, medial malleolus and lateral malleolus). The correlation between radiographic findings and arthroscopic findings were analyzed. Results: In Mortise view, strong correlations were found between lateral tibial osteophyte grade and ICRS grade of the center (talus R = 0.69, tibia R = 0.76), the central lateral (tibia R = 0.79), the posterior center (talus R = 0.72, tibia R = 0.74) and the posterior lateral of the tibiotalar joint (talus R = 0.63, tibia R = 0.76). There are moderate correlations between distal fibular osteophyte grade and ICRS grade of the medial inner (tibia R = 0.74) and the posterior medial of the tibiotalar joint (talus R = 0.61, tibia = 0.63). In lateral view, there are moderate correlations between posterior talar osteophyte grade and ICRS grade at the center of the tibiotalar joint (talus R = 0.61, tibia R = 0.60). Conclusion: From this study, there was a strong correlation between location and grade osteophyte and the articular cartilage injury. Osteoarthritis progression is caused by degeneration of the cartilage because of the joint instability, and osteophytes were formed by traction force or impaction. This study showed that local cartilage injury is thought to be related to osteophytes. By evaluating the location and size of osteophytes, the articular cartilage injury might be predicted accurately before arthroscopic surgery.

Category: Midfoot/Forefoot Introduction/Purpose: We developed a new screening method for hallux valgus during weight bearing using the photo-capturing function in cell phones. Methods: We compared apparent hallux valgus angles measured from photographs of people in a standing position during weight bearing, which were captured on a smartphone (smartphone Hallux Valgus Angle: SP-HVA) (Smartphone Method), with hallux valgus angles determined using conventional radiography in a standing posture during weight-bearing (X-ray HVA: XR-HVA). We evaluated 37 feet of 25 patients (5 men and 25 women) who visited our hospital. The mean age at the time of the visit was 73.9 years. In the Smartphone Method, subjects stood upright and the examiner used a smartphone to take photos of both feet from above while holding the phone at the level of the anterior knee. Results: The mean value was 36.2° for SP-HVA and 36.7° for XR-HVA; the two methods showed a statistically significant correlation (correlation coefficient of 0.86). Conclusion: Our smartphone-assisted screening method for hallux valgus was possible to make a diagnosis equivalent to conventional radiography method without radiation exposure.

Category: Ankle Arthritis Introduction/Purpose: Ankle arthrodesis is still the primary treatment for end-stage arthritis of the ankle that does not respond to conservative treatment. However, comparative studies demonstrated that the patients’ functional outcomes remain significantly lower than normal, progression of subtalar and midfoot arthritis and there could be measurable abnormalities in their gait parameters. Previous studies demonstrated gait analysis after ankle arthrodesis using 3D motion capture system. These studies used a single segment foot model, which had the limitation of detailed motion analysis. 3D multi-segmental foot model enables to perform detailed analysis segmentally such as fore foot and hind foot. The purpose of this study was to examine foot kinematics during walking after ankle arthrodesis using 3D multi-segment foot model as compared with a healthy control group. Methods: Between 2014 and 2016, nine patients who underwent an isolated ankle arthrodesis were followed for a mean 2 years after surgery, and five control subjects were included for comparison. Physical examination, radiographic examination and gait examination were performed. For gait analysis Vicon Nexus system with 16 MX-Cameras was used to capture foot kinematics during barefoot walking at self-selected speed along a 10 m walkway. Markers were placed according to the Oxford Foot Model (OFM). Patients completed preoperative and annual postoperative functional outcome scores including the Japanese Society for Surgery of the Foot (JSSF) scale. Results: JSSF scale was significantly improved from pre-operation to post-operation (50 points versus 85 points; p

Category: Ankle Introduction/Purpose: Previous studies have described the damage of sensori-motor control in ankle sprain as being a possible cause of functional instability. The methods to demonstrate the functional instability, have included the postural balance test, peroneal muscle reaction time to sudden ankle inversion, peroneal nerve conduction velocity, and joint position sense of the ankle. On the other hand, isokinetic fatigue of ankle plantar flexion and dorsiflexion exhibits the correlation with postural instability. We hypothesize muscle fatigue around ankle joint causes abnormality of joint position sense, especially inversion at ankle joint, and it will be one of the causes of the ankle sprain. The aim of this study was to evaluate the inversion angle replication errors of before fatigue and after fatigue. Methods: 11 subjects were included in this study. The subjects were placed in a sitting position with the knee flexed at 70°. Each subject placed the foot on a goniometer footplate with the ankle at 20° planter flexion. Subjects were blindfolded to eliminate visual input and to facilitate concentration during testing. The foot was passively rotated internally at random to one of six positions (5°to 30°), always starting from 0°. The footplate was rotated manually to the index angle in approximately 1 s, and held in position for 5 s. Then the ankle was returned to the 0° position. After that, the subjects moved their ankle to match the previous test angle actively. The difference between the index angle and replication angle was measured. Ankles were enforced planter and dorsiflexion according to previous reports, and replication error was measured before and after fatigue. Results: The side-to-side difference of the replication errors was 1.9±1.7° in the before-fatigue group and 2.6±1.8° in the after-fatigue group. There was a statistically significant difference between both the groups (p

Background: Injury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint. Methods: MCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week. Results: Histological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis. Conclusion: This study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site.

Ankle arthroscopy is a minimally invasive technique for ankle joint treatment. However, injury to the intermediate dorsal cutaneous nerve (IDCN) and the medial dorsal cutaneous nerve (MDCN) is a common complication during anterior portal placement. To prevent injuries, methods such as palpating the nerves topographically and marking the nerves by transilluminating the skin with an arthroscope have been proposed. Easier and more definitive methods of identifying the IDCN and MDCN should result in a reduction of complications. Recently, a vein imaging system was developed that projects images of subcutaneous vasculature directly onto the skin with the use of near-infrared (NIR) light. Because anatomic studies have shown that superficial veins accompany the IDCN and MDCN, protecting the subcutaneous veins could lower the risk of nerve injury. We introduce our technique for the creation of an ankle arthroscopic portal using an NIR imaging system, which displays the vein image on the skin, to prevent injury to the superficial veins and, consequently, reduce IDCN and MDCN injuries. This is the first technical report on the prevention of vein and nerve injuries using an NIR imaging system. Our technique for avoiding vein injury using a peripheral vein illumination device during anterior portal placement in ankle arthroscopy could lower the risk of complications.

Objectives: Ageing and obesity are major risk factors for osteoarthritis (OA), a widespread disease currently lacking efficient treatments. Senescence-accelerated mouse prone 8 (SAMP8) display early onset ageing phenotypes, including OA. This study investigates the impacts of high-fat diet (HFD)-induced obesity on OA development in SAMP8. Methods: SAMP8 at 5 weeks were fed either a normal chow diet or an HFD for 10 weeks to induce obesity. Parameters related to obesity, liver function, and lipid and glucose metabolism were analysed. At 14 weeks of age, knee joint pathology, bone mineral density, and muscle strength were assessed. Immunohistochemistry and TUNEL staining were performed to evaluate markers for cartilage degeneration and chondrocyte apoptosis. Results: At 14 weeks of age, HFD-induced obesity increased liver and adipose tissue inflammation in SAMP8 without further exacerbating diabetes. Histological scoring revealed aggravated cartilage, menisci deterioration, and synovitis, while no further loss of bone mineral density or muscle strength was observed. Increased chondrocyte apoptosis was detected in knee joints following HFD feeding. Conclusions: Ten weeks of HFD feeding promotes spontaneous OA progression in 14-week-old SAMP8, potentially via liver damage that subsequently leads to chondrocyte apoptosis. This ageing-obese mouse model may prove valuable for further exploration of spontaneous OA pathophysiology. [ABSTRACT FROM AUTHOR]