Relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in patients with hallux valgus.

OBJECTIVES: Hallux valgus is associated with tarsometatarsal arthritis; its pathophysiology remains unknown. Therefore, we aimed to elucidate the relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in the sagittal plane. METHODS: Forty-three patients (64 feet) with hallux valgus who underwent surgery at University Hospital Kyoto Prefectural University of Medicine were included and divided into two groups: control (without second and third tarsometatarsal joint degeneration) and osteoarthritis (with second and third tarsometatarsal joint degeneration). Intergroup comparisons of the incongruity of the first tarsometatarsal joint in the sagittal plane, age, body mass index, hallux valgus angle, first-second intermetatarsal angle, metatarsus adductus angle, Meary's angle, and calcaneal pitch angle were performed. RESULTS: The proportion of patients with incongruity of the first tarsometatarsal joint was significantly higher in the osteoarthritis group than in the control group. Logistic regression analysis identified incongruity of the first tarsometatarsal joint and metatarsus adductus angle as significant related factors for arthritis of the second and third tarsometatarsal joints. CONCLUSIONS: Incongruity of the first tarsometatarsal joint in the sagittal plane was involved in the development of arthritis of the second and third tarsometatarsal joints in patients with hallux valgus.

The inter-prefectural regional disparity of healthcare resources and representative surgical procedures in orthopaedics and general surgery: a nationwide study in Japan during 2015-2019.

BACKGROUND: Few reports have examined the localized regional disparity in representative surgical procedures in orthopaedics and general surgery globally. This study aimed to clarify the inter-prefectural regional disparity and relationships between healthcare resources and representative surgical procedures using a nationwide database in Japan. METHODS: The number of medical specialists in orthopaedics, general surgery, and anaesthesiology, as well as the number of hospitals, and the incidence of representative surgical procedures in orthopaedics and general surgery were evaluated annually per 100,000 inhabitants/people by prefecture in Japan during 2015-2019. Medium-sized regional disparities were evaluated using the Gini coefficient. Correlation coefficients were calculated for the defined variables and ageing rate. We also compared the urban and rural regional disparities in all study variables. RESULTS: The annual average number/incidence and Gini coefficients were 110.6 and 0.11 for femur fracture surgery, 106.3 and 0.09 for cholecystectomy, 14.2 and 0.11 for orthopaedic surgeon specialists, 17.6 and 0.09 for general surgeon specialists, 5.9 and 0.13 for anaesthesiology specialists, and 8.1 and 0.21 for hospitals, respectively. The correlation coefficients by the incidence of femur fracture surgery were 0.74 for orthopaedic surgeon specialists (p < 0.001), 0.63 for hospitals (p < 0.001), and 0.62 for the ageing rate (p < 0.001); those by the incidence of cholecystectomy were 0.60 for general surgeon specialists (p < 0.001) and 0.59 for hospitals (p < 0.001). The number/incidence of orthopaedic surgeon specialists, hospitals, femur fracture surgery, and cholecystectomy, as well as the ageing rate, were significantly higher in rural prefectures than in urban prefectures (p < 0.05). CONCLUSIONS: Inter-prefectural regional disparity was small, although certain items were unevenly distributed in the rural prefectures, which is contrary to our expectations. Higher prevalence was recognised in rural prefectures due to the higher ageing rate; however, supply and demand are balanced. This study provides basic data for healthcare policy development in a medium-sized community. LEVEL OF EVIDENCE: III.

Indication for Achilles Tenotomy in Congenital Clubfoot: Effectiveness of Using the Tibio-Plantar Fascia Angle as a Radiographic Parameter.

Congenital clubfoot is one of the most common deformities in children, and currently, the Ponseti method is used worldwide because of its favorable short-term results. With the Ponseti method, the indication for Achilles tenotomy is traditionally based on only physical examination findings; however, some surgeons have also utilized plain radiographs. Because using physical examinations to determine the degree of hindfoot dorsiflexion for the indication of tenotomy can lead to underestimation. We developed and utilized the effectiveness of the tibio-plantar fascia angle (Ti-P angle) in the lateral maximum dorsiflexion view in determining the need for Achilles tenotomy. A retrospective analysis of consecutive 26 patients with congenital idiopathic clubfeet (37 feet) was performed. Whether Achilles tenotomy was indicated was determined based on physical examination for a former period (Group P). For the latter period, whether tenotomy was indicated was determined by referencing radiographs (Group X). No significant differences were found in any of the background factors or severity between Group P and Group X. Cases with larger tibiocalcaneal and Ti-P angles were more likely to require Achilles tenotomy or additional soft tissue release. An angle of more than 72° of the Ti-P angle demonstrated adequate specificity for the indication of Achilles tenotomy. The radiographic lateral tibio-plantar fascia angle is useful for deciding whether a tenotomy needs to be performed.

Trends and age- and sex-stratified analysis of hallux valgus correction surgery from 2014 to 2019: A nationwide population-based cohort study in Japan.

BACKGROUND: Epidemiological studies on hallux valgus (HV) are challenging owing to differences in sampling and diagnostic criteria across studies. This study aimed to indirectly clarify HV epidemiology using a national database. METHODS: The age- and sex-stratified annual number rate of HV correction (RHVC) per 100,000 people in Japan during 2014-2019 were examined. RESULTS: The average annual RHVC was 3.0. RHVC had unimodal (peak, 65-79 years) and bimodal (peaks, 15-19 and 70-74 years) distributions among males and females, respectively, and increased over time in males aged 50-54 and 75-79 years and females aged 80-84 years. CONCLUSIONS: RHVC increases with increasing age and occurs commonly in female teens. The recent RHVC in Japan was lower than that reported in Europe and the United States, with an increasing trend among elderly people. LEVEL OF EVIDENCE: III.

Sweep imaging with Fourier transform as a tool with MRI for evaluating the effect of teriparatide on cortical bone formation in an ovariectomized rat model.

BACKGROUND: Teriparatide (TPTD) is a drug for osteoporosis that promotes bone formation and improves bone quality. However, the effects of TPTD on cortical bone are not well understood. Sweep imaging with Fourier transform (SWIFT) has been reported as a useful tool for evaluating bound water of cortical bone, but it has yet to be used to investigate the effects of TPTD on cortical bone. This study aimed to evaluate the consequences of the effect of TPTD on cortical bone formation using SWIFT. METHODS: Twelve-week-old female Sprague-Dawley rats (n = 36) were reared after ovariectomy to create a postmenopausal osteoporosis model. They were divided into two groups: the TPTD and non-TPTD groups. Rats were euthanized at 4, 12, and 24 weeks after initiating TPTD treatment. Tibial bones were evaluated using magnetic resonance imaging (MRI) and bone histomorphometry. In MRI, proton density-weighted imaging (PDWI) and SWIFT imaging were performed. The signal-to-noise ratio (SNR) was calculated for each method. The same area evaluated by MRI was then used to calculate the bone formation rate by bone histomorphometry. Measurements were compared using the Mann-Whitney U-test, and a P-value of < 0.05 was considered significant. RESULTS: PDWI-SNR was not significantly different between the two groups at any time point (P = 0.589, 0.394, and 0.394 at 4, 12, and 24 weeks, respectively). Contrarily, SWIFT-SNR was significantly higher in the TPTD group than in the non-TPTD group at 4 weeks after initiating treatment, but it was not significantly different at 12 and 24 weeks (P = 0.009, 0.937, and 0.818 at 4, 12, and 24 weeks, respectively). The bone formation rate assessed by histomorphometry was significantly higher in the TPTD group than in the non-TPTD group at all timepoints (P < 0.05, all weeks). In particular, at 4 weeks, the bone formation rate was markedly higher in the TPTD group than in the non-TPTD group (P = 0.028, 1.98 ± 0.33 vs. 0.09 ± 0.05 µm3/µm2/day). CONCLUSIONS: SWIFT could detect increased signals of bound water, reflecting the effect of TPTD on the cortical bone. The signal detected by SWIFT reflects a marked increase in the cortical bone formation rate.

Foot orthosis treatment improves physical activity but not muscle quantity in patients with concurrent rheumatoid arthritis and sarcopenia.

OBJECTIVES: Foot impairment in rheumatoid arthritis (RA) may exacerbate sarcopenia from physical inactivity because of foot pain while walking. The present study aimed to investigate the prevalence of sarcopenia in patients with RA-associated foot impairment, and whether treatment with a foot orthosis improved physical activity and muscle quantity. METHODS: Thirty-two patients with RA were diagnosed as sarcopenic or nonsarcopenic, and the prevalence of sarcopenia was determined. Eleven patients with sarcopenia were treated with a foot orthosis. The following parameters were compared between baseline and after 6 months of treatment: physical activity (walking, moderate-intensity activity, and vigorous-intensity activity), foot pain while walking, Health Assessment Questionnaire (HAQ) score, and body composition parameters, including muscle quantity. RESULTS: Sarcopenia was present in 25/32 patients (78.1%). The use of a foot orthosis improved walking activity (p = .02), foot pain while walking (p = .02), and HAQ score (p = .02). However, there were no significant changes in moderate- or vigorous-intensity activities or body composition parameters, including muscle quantity. CONCLUSION: Patients with RA-associated foot impairment had a high rate of sarcopenia. Treatment with a foot orthosis increases light-intensity physical activity such as walking, but does not enhance moderate-to-vigorous-intensity activities or increase muscle quantity.

Status of growth plates can be monitored by MRI.

BACKGROUND: Growth plate injuries and disorders cause premature closure, resulting in shortened or deformed limbs. Quantitative assessment by MRI might monitor the status of the growth plate and may assist in the prediction of these deformations. PURPOSE: To investigate whether the status of the growth plate can be monitored by quantitative evaluation using MRI of the noninjured region of the growth plate in a physeal injury model. STUDY TYPE: Prospective, longitudinal. ANIMAL MODEL: A 3.0-mm drill was used to create an injury to the central region of the right proximal tibial growth plate in 5-week-old male Japanese white rabbits (N = 18). The left tibia served as the control. FIELD STRENGTH/SEQUENCE: 7.04T, T2 -weighted imaging, diffusion-weighted imaging. ASSESSMENT: Eight of 18 rabbits underwent MRI, proton density-weighted imaging, and T2 -weighted and diffusion-weighted imaging. T2 and apparent diffusion coefficient (ADC) maps were generated for each image. The growth plate height and the T2 and ADC values of the noninjured region were measured. Two rabbits were sacrificed at 2, 4, 6, 8, and 10 weeks postinjury. Proximal tibial bones were evaluated using microcomputed tomography, histological, and immunohistological methods. STATISTICAL TESTS: Data were compared using repeated-measures analysis of variance followed by Tukey post-hoc multiple comparison. RESULTS: Growth plate height decreased at 10 weeks postinjury (P = 0.018) on the injured side. T2 values were greater at 2 weeks postinjury (P = 0.0478) and decreased at 8 and 10 weeks (P = 0.0226, P = 0.0470, respectively) on the injured side. ADC values increased at 6 weeks on the lateral side (P = 0.0304) and decreased at 8 weeks and 10 weeks postinjury (P < 0.01) on the medial and injured sides, respectively. DATA CONCLUSION: Quantitative MRI can help monitor the status of the growth plate and capture its changes early. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:133-143.

The influence of hallux valgus and flatfoot deformity on metatarsus primus elevatus: A radiographic study.

BACKGROUND: Metatarsus primus elevatus (MPE), a dorsal elevation of the first metatarsal in relation to the lesser metatarsals on lateral-view radiographs, is an indicator of hallux rigidus. The angle between the articular surfaces of the base of the first metatarsal and the anterior part of the medial cuneiform (M1C1A) reflects the sagittal instability of the first tarsometatarsal (TMT) joint. MPE may also indicate instability of the first metatarsal. The purpose of this study was to identify the influence of hallux valgus (HV) and flatfoot (FF) deformities on measurements obtained from first metatarsal-related radiographic images. METHODS: Standing radiographic images of 134 feet were investigated. In dorsoplantar-view radiographs, HV and intermetatarsal angles were evaluated. The position of the medial sesamoid was classified with a grading system (Hardy score). In lateral-view radiographs, MPE, M1C1A, and Meary's angle were measured. The subjects were divided into 4 groups: the normal group (G1), HV(-)FF(-); the HV group (G2), HV(+)FF(-); the FF group (G3), HV(-)FF(+); and the dual group (G4), HV(+)FF(+). The radiographic parameters were compared among the groups. RESULTS: MPE in the HV patients (G2 and G4) was less than that in the non-HV participants (G1 and G3). MPE in G4 was less than that in G3. The odds ratios of the Hardy score were higher in G2, G3 and G4 than in G1. The ratios were higher in the FF patients (G3 and G4) than in the non-FF participants (G1 and G2) and were higher in G4 than in G2. CONCLUSIONS: FF affects sesamoid dislocation, and the combination of HV and FF further increases sesamoid dislocation. Combined with M1C1A and the Hardy score, MPE may be a useful indicator of three-dimensional instability of the first TMT joint. First TMT joint-related operations may be considered for severe HV treatment in G4 patients.

Early stage and small medial osteochondral lesions of the talus in the presence of chronic lateral ankle instability: A retrospective study.

BACKGROUND: In chronic lateral ankle instability (CLAI), the instability of the ankle joint results in repeated microtrauma to the articular cartilage. How the lesion condition or stage is affected by the presence of lateral instability in medial osteochondral lesions of the talus (OLT) is unclear. We aimed to examine whether CLAI is associated with the size and staging of medial OLT on radiographs, magnetic resonance (MR) images, and arthroscopy. METHODS: Forty-five patients with medial OLTs in 45 ankles were reviewed. Radiographs were assessed for damage and lesion classification. The tibio-talar tilting angle (TTA) was measured. The patients were divided into two groups: the CLAI group and the stable group. The lesion classification on radiographs, MR images, and arthroscopy, and size on MR images were statistically compared. RESULTS: The CLAI group had a mean TTA of 8.15 ± 3.41°, whereas the stable group had a mean TTA of 2.24 ± 1.64°. The CLAI group had a lower clinical score than the stable group at the initial visit to our clinic. The CLAI group presented with lesions of significantly shorter longitudinal and transverse diameters. Stages of medial OLT on radiographs, MR images, and arthroscopic evaluation were earlier in the CLAI group than those in the stable group. CONCLUSIONS: Patients with CLAI presented in the early stages of OLT and had significantly smaller lesions than those without CLAI. The patients without CLAI may be selected for surgery at an early phase.

Transiently proliferating perivascular microglia harbor M1 type and precede cerebrovascular changes in a chronic hypertension model.

BACKGROUND: Microglia play crucial roles in the maintenance of brain homeostasis. Activated microglia show a biphasic influence, promoting beneficial repair and causing harmful damage via M2 and M1 microglia, respectively. It is well-known that microglia are initially activated to the M2 state and subsequently switch to the M1 state, called M2-to-M1 class switching in acute ischemic models. However, the activation process of microglia in chronic and sporadic hypertension remains poorly understood. We aimed to clarify the process using a chronic hypertension model, the deoxycorticosterone acetate (DOCA)-salt-treated Wistar rats. METHODS: After unilateral nephrectomy, the rats were randomly divided into DOCA-salt, placebo, and control groups. DOCA-salt rats received a weekly subcutaneous injection of DOCA (40 mg/kg) and were continuously provided with 1% NaCl in drinking water. Placebo rats received a weekly subcutaneous injection of vehicle and were provided with tap water. Control rats received no administration of DOCA or NaCl. To investigate the temporal expression profiles of M1- and M2-specific markers for microglia, the animals were subjected to the immunohistochemical and biochemical studies after 2, 3, or 4 weeks DOCA-salt treatment. RESULTS: Hypertension occurred after 2 weeks of DOCA and salt administration, when round-shaped microglia with slightly shortened processes were observed juxtaposed to the vessels, although the histopathological findings were normal. After 3 weeks of DOCA and salt administration, M1-state perivascular and parenchyma microglia significantly increased, when local histopathological findings began to be observed but cerebrovascular destruction did not occur. On the other hand, M2-state microglia were never observed around the vessels at this period. Interestingly, prior to M1 activation, about 55% of perivascular microglia transiently expressed Ki-67, one of the cell proliferation markers. CONCLUSIONS: We concluded that the resting perivascular microglia directly switched to the pro-inflammatory M1 state via a transient proliferative state in DOCA-salt rats. Our results suggest that the activation machinery of microglia in chronic hypertension differs from acute ischemic models. Proliferative microglia are possible initial key players in the development of hypertension-induced cerebral vessel damage. Fine-tuning of microglia proliferation and activation could constitute an innovative therapeutic strategy to prevent its development.

Treadmill Running in Established Phase Arthritis Inhibits Joint Destruction in Rat Rheumatoid Arthritis Models.

Exercise therapy inhibits joint destruction by suppressing pro-inflammatory cytokines. The efficacy of pharmacotherapy for rheumatoid arthritis differs depending on the phase of the disease, but that of exercise therapy for each phase is unknown. We assessed the differences in the efficacy of treadmill running on rheumatoid arthritis at various phases, using rat rheumatoid arthritis models. Rats with collagen-induced arthritis were used as rheumatoid arthritis models, and the phase after immunization was divided as pre-arthritis and established phases. Histologically, the groups with forced treadmill running in the established phase had significantly inhibited joint destruction compared with the other groups. The group with forced treadmill running in only the established phase had significantly better bone morphometry and reduced expression of connexin 43 and tumor necrosis factor α in the synovial membranes compared with the no treadmill group. Furthermore, few cells were positive for cathepsin K immunostaining in the groups with forced treadmill running in the established phase. Our results suggest that the efficacy of exercise therapy may differ depending on rheumatoid arthritis disease activity. Active exercise during phases of decreased disease activity may effectively inhibit arthritis and joint destruction.

Heme oxygenase-1 prevents glucocorticoid and hypoxia-induced apoptosis and necrosis of osteocyte-like cells.

Glucocorticoids and hypoxia is considered to promote osteocyte apoptosis and necrosis, which are observed in glucocorticoid-associated osteonecrosis and osteoporosis. Heme oxygenase-1 (HO-1) induced by hemin is reported to have cytoprotective effects in ischemic diseases. The objective of this study was to evaluate the effect of HO-1 on osteocyte death caused by glucocorticoids and hypoxia. We confirmed that hemin induced HO-1 expression in MLO-Y4 mouse osteocytes. MLO-Y4 was cultured with dexamethasone (Dex) under hypoxia (DH group). Furthermore, these cells were cultured with hemin (DH-h group) or hemin and zinc protoporphyrin IX (an HO-1 inhibitor) (DH-h-PP group). The rates of apoptosis and necrosis of these groups were analyzed by flow cytometry and compared with cells cultured under normal condition. Both apoptosis and necrosis increased in the DH group. Hemin administration significantly reduced cell death caused by glucocorticoids and hypoxia in the DH-h group, and its effect was attenuated by the HO-1 inhibitor in DH-h-PP group. Capase-3 activity significantly decreased in the DH-h group. This implied that the cell death inhibition effect due to hemin is mediated by HO-1 and caspase-3. HO-1 induction may be useful in the treatment of glucocorticoid-associated osteonecrosis and osteoporosis.

Angiotensin 1-7 stimulates brown adipose tissue and reduces diet-induced obesity.

The renin-angiotensin system is a key regulator of metabolism with beneficial effects of the angiotensin 1-7 (Ang 1-7) peptide. We hypothesized that the antiobesity effect of Ang 1-7 was related to the stimulation of brown adipose tissue (BAT). We administered Ang 1-7 (0.54 mg kg-1 day-1) for 28 days via implanted micro-osmotic pumps to mice with high-fat diet (HFD)-induced obesity. Ang 1-7 treatment reduced body weight, upregulated thermogenesis, and ameliorated impaired glucose homeostasis without affecting food consumption. Furthermore, Ang 1-7 treatment enlarged BAT and the increased expression of UCP1, PRDM16, and prohibitin. Alterations in PRDM16 expression correlated with increased AMPK and phosphorylation of mTOR. Ang 1-7 treatment elevated thermogenesis in subcutaneous white adipose tissue without altering UCP1 expression. These changes occurred in the context of decreased lipid accumulation in BAT from HFD-fed mice, preserved insulin signaling concomitant with phosphorylation of hormone-sensitive lipase and decreased expression of perilipin. These data suggest that Ang 1-7 induces brown adipocyte differentiation leading to upregulation of thermogenesis and improved metabolic profile in diet-induced obesity. Enhancing Ang 1-7 action represents a promising therapy to increase BAT and to reduce the metabolic complications associated with diet-induced obesity.

Usefulness of Sweep Imaging With Fourier Transform for Evaluation of Cortical Bone in Diabetic Rats.

BACKGROUND: Diabetes decreases bone strength, possibly because of cortical bone changes. Sweep imaging with Fourier transform (SWIFT) has been reported to be useful for cortical bone evaluation. PURPOSE: To evaluate cortical bone changes in diabetic rats using SWIFT, assess the usefulness of this technique through comparisons with microcomputed tomography (µCT) and conventional MRI, and clarify the mechanism underlying cortical bone changes using histomorphometry STUDY TYPE: Animal cohort. ANIMAL MODEL: 8-week-old male Wistar/ST rats (N = 36) were divided into diabetes (induced by streptozotocin injection) and control groups. FIELD STRENGTH/SEQUENCE: 7.04T MRI, SWIFT. ASSESSMENT: Six animals from each group were sacrificed at 2, 4, and 8 weeks after injection. Tibial bones were extracted and evaluated using µCT and MRI. The cortical bone mineral density (BMD) was measured using µCT. Proton density-weighted imaging (PDWI) and SWIFT were also performed. The signal-to-noise ratio (SNR) was calculated for each acquisition. The bone formation rate was evaluated using histomorphometry. STATISTICAL TESTS: Findings at each timepoint were compared using Mann-Whitney U-tests. RESULTS: Cortical BMD was significantly lower in the diabetes group than in the control group only at 8 weeks (P < 0.05). At all timepoints, PDWI-SNR showed no significant differences between groups (P = 0.59, 0.70, and 0.82 at 2, 4, and 8 weeks, respectively). SWIFT-SNR was significantly lower in the diabetes group than in the control group (P < 0.05 at 2 and 4 weeks and P < 0.01 at 8 weeks), and the bone formation rate was significantly lower in the diabetes group than in the control group (P < 0.01 for all). DATA CONCLUSION: SWIFT can detect cortical bone changes even before a decline in the cortical BMD in a diabetic model. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2018;48:389-397.

Early detection of osteoarthritis in rabbits using MRI with a double-contrast agent.

BACKGROUND: Articular cartilage degeneration has been evaluated by magnetic resonance imaging (MRI). However, this method has several problems, including its time-consuming nature and the requirement of a high magnetic field or specialized hardware. The purpose of this study was to sequentially assess early degenerative changes in rabbit knee articular cartilage using MRI with a new double-contrast agent. METHODS: We induced osteoarthritis (OA) in the right knee of rabbits by anterior cruciate ligament transection and partial medial meniscectomy. Proton density-weighted images and T2-calculated images were obtained before and after contrast agent injection into the knee. The signal intensity ratio (SIR) values on the proton density-weighted images were calculated by dividing the signal intensity of the articular cartilage by that of joint fluid. Six rabbits were examined using MRI at 2 (designated 2-w OA) and 4 weeks (4-w OA) after the operation. Histological examination was performed 4 weeks after the operation. One rabbit was histologically examined 2 weeks after the operation. The control consisted of six rabbits that were not subjected to the operation. The SIR values, T2 values and the thicknesses of the cartilage of the 2-w OA, 4-w OA and the control before and after contrast agent injection were analyzed. The Mankin score and OARSI (Osteoarthritis Research Society International) score were used for the histological evaluation. RESULTS: Significant differences in the SIR and T2 values of the medial and lateral condyles of the femur were found between the control and the 4-w OA only after contrast agent injection. No significant differences were found in the SIR and T2 values before contrast agent injection between the control, the 2-w OA and 4-w OA. The thickness of the articular cartilage revealed no significant differences. In the histological assessment, the Mankin score and OARSI score sequentially increased from the control to the 4-w OA. CONCLUSION: We evaluated the SIR and T2 values of the knees in a rabbit OA model and a control model using a new double-contrast agent. MRI with this agent enabled OA detection earlier than using conventional MRI.

Length change patterns and shape of a grafted tendon after anatomical medial patellofemoral ligament reconstruction differs from that in a healthy knee.

PURPOSE: Recurrent patellar dislocation is currently treated with anatomical reconstruction of the medial patellofemoral ligament (MPFL), and favourable postoperative outcomes have been reported. However, it is uncertain if healthy MPFL function is restored by anatomical reconstruction. The hypothesis in this study was that stabilization of the patella following MPFL reconstruction would be improved compared with that before surgery, but that function of the grafted tendon would differ from that of a healthy MPFL. The objective was to analyse the length change patterns of the MPFL before surgery and the grafted tendon after surgery in patients with recurrent patellar dislocation treated with anatomical MPFL reconstruction. METHODS: The subjects were 12 patients (13 knees) in whom recurrent patellar dislocation was treated with anatomical MPFL reconstruction. The length change patterns of the MPFL and reconstructed ligament were analysed at extension and flexion of the knee joint using open MRI. RESULTS: The postoperative grafted tendon length was significantly shorter than that of the preoperative MPFL at knee extension, and significantly longer at 90° and 120° of knee flexion. The postoperative length of the grafted tendon only changed slightly from 0° to 30° of knee flexion, and then significantly decreased at flexion of 30° or more. The morphology of the grafted tendon was linear until 60° knee flexion, but became convex toward the extraarticular side at flexion of 90° or more. CONCLUSION: The grafted tendon length at knee extension was shorter than that of the preoperative MPFL, but there was no significant difference at 30° flexion. These findings suggest that the effect of damping of the patella with a grafted tendon after MPFL reconstruction may differ from that in a healthy knee. In addition, the morphology at 60° knee flexion was improved to linear after surgery, suggesting that ligament morphology at this flexion was normalized by MPFL reconstruction. LEVEL OF EVIDENCE: III.

Treadmill Running Ameliorates Destruction of Articular Cartilage and Subchondral Bone, Not Only Synovitis, in a Rheumatoid Arthritis Rat Model.

We analyzed the influence of treadmill running on rheumatoid arthritis (RA) joints using a collagen-induced arthritis (CIA) rat model. Eight-week-old male Dark Agouti rats were randomly divided into four groups: The control group, treadmill group (30 min/day for 4 weeks from 10-weeks-old), CIA group (induced CIA at 8-weeks-old), and CIA + treadmill group. Destruction of the ankle joint was evaluated by histological analyses. Morphological changes of subchondral bone were analyzed by µ-CT. CIA treatment-induced synovial membrane invasion, articular cartilage destruction, and bone erosion. Treadmill running improved these changes. The synovial membrane in CIA rats produced a large amount of tumor necrosis factor-α and Connexin 43; production was significantly suppressed by treadmill running. On µ-CT of the talus, bone volume fraction (BV/TV) was significantly decreased in the CIA group. Marrow star volume (MSV), an index of bone loss, was significantly increased. These changes were significantly improved by treadmill running. Bone destruction in the talus was significantly increased with CIA and was suppressed by treadmill running. On tartrate-resistant acid phosphate and alkaline phosphatase (TRAP/ALP) staining, the number of osteoclasts around the pannus was decreased by treadmill running. These findings indicate that treadmill running in CIA rats inhibited synovial hyperplasia and joint destruction.

Evaluation of femoral perfusion using dynamic contrast-enhanced MRI after simultaneous initiation of electrical stimulation and steroid treatment in an osteonecrosis model.

This study aimed to evaluate femoral perfusion using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for two weeks after the simultaneous initiation of electrical stimulation (ES) and steroid treatment in a steroid-induced osteonecrosis (ON) model. A single dose of methylprednisolone was injected into 14 rabbits. Seven rabbits underwent ES (ES group), and seven rabbits did not (control group). DCE-MRI was performed before steroid administration and 1, 5, 10, and 14 days after steroid administration. Regions of interest were set in the bilateral proximal femora. The enhancement ratio, initial slope, and area under the curve were analyzed. These parameters were evaluated after steroid administration in each group and between the two groups, and the ratios of ON in both groups were compared. In the control group, the minimum values of all parameters decreased significantly after steroid administration (P < 0.05), but in the ES group, the parameters did not decrease. In the ES group, all parameter values were significantly increased on the 10th and 14th days (P < 0.05). All parameter values in the ES group were significantly higher than those in the control group on the 14th day (P < 0.05). In the control group, ON was detected in three of five rabbits (in three of ten femora). In the ES group, ON was not detected. These results suggest that increased femoral blood flow elicited by ES may be related to ON prevention after steroid administration.

Comparative analysis of medial patellofemoral ligament length change pattern in patients with patellar dislocation using open-MRI.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction has become a common form of treatment for recurrent patellar dislocation. This study was performed using open-MRI to compare the length change pattern of MPFL in patients with a history of patellar dislocation to that in healthy subjects. METHODS: The subjects comprised 10 knees of 8 males and 13 knees of 12 females with a history of one or more patellar dislocations. The length of the MPFL was measured using open-MRI in both the leg-extended position and knee-flexed positions to analyse the length change pattern. RESULTS: The average MPFL lengths were 58.6 ± 6.5 mm and 52.0 ± 4.6 mm for males and females in the extended knee position, respectively. The length change pattern of the MPFL showed slight variation up to a flexion angle of 30° and a clear decrease above 30°. This pattern differed from that of normal MPFL. In terms of morphology, the fibre bundle of the damaged MPFL followed a convex course towards the side of the patellofemoral joint surface at a knee flexion angle of 60°, whereas that of the normal MPFL followed a straight course. CONCLUSION: The in vivo damaged MPFL length change pattern was specific and differed distinctly from that of normal MPFL. The results of the present study suggested that MPFL fibres with a history of patellar dislocation lack sufficient tension at knee flexion angles of 0°-60°. However, further studies are needed to obtain a better understanding of cases with a patellar dislocation or postsurgical cases of MPFL reconstruction. LEVEL OF EVIDENCE: III.

Relationship Between Grading With Magnetic Resonance Imaging and Radiographic Parameters in Posterior Tibial Tendon Dysfunction.

The objective of the present study was to elucidate the relationship between the state of the posterior tibial tendon (PTT) on magnetic resonance images and foot deformity. The cases included 34 feet in 27 patients with PTT deformity and the controls included 18 feet in 12 patients who had undergone magnetic resonance imaging for other foot diseases. The PTT was closely examined on the magnetic resonance images and classified using the Conti classification. The control feet with no injury to the PTT were classified as grade 0. The talonavicular coverage angle, lateral talo-first metatarsal angle, medial cuneiform to fifth metatarsal height, calcaneal pitch angle, and varus-valgus angle were measured as radiographic parameters for flatfoot deformation, and the relation between the Conti classification and each parameter was examined statistically. A significant difference was observed in the talonavicular coverage angle between grade 0 and the other grades; the lateral talo-first metatarsal angle between grade 0 and the other grades and between grades 1 and 3; the medial cuneiform to fifth metatarsal height among grades 0, 2, and 3 and grades 1, 2, and 3; the calcaneal pitch angle between grades 1 and 3; and the varus-valgus angle among grades 0, 2, and 3 and between grades 1 and 3. Eversion of the forefoot was observed, along with an advanced collapse in the medial longitudinal arch, from an early stage of PTT injury.