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.

Reproducibility of radiographic methods for assessing longitudinal tarsal axes Part 2: Severe cavus or flatfoot study.

INTRODUCTION: Calcaneal pitch angle and Meary's angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. The aim of this study was to examine and evaluate the radiographic longitudinal foot arch measurement methods with the best intraobserver and interobserver reliabilities for patients with (1) severe cavus deformity and (2) severe flatfoot deformity. METHODS: Standing radiographic images of 22feet with severe cavus foot deformity and 49feet with severe flatfoot deformity were obtained to measure the longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. RESULTS: The results are generally consistent with those of Part 1. The best intraobserver and interobserver correlation coefficients for the tarsal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach. CONCLUSIONS: The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches in patients with severe cavus or flatfoot deformity. This study may contribute to the more accurate assessment of any foot deformity.

Reproducibility of radiographic methods for assessing longitudinal tarsal axes: Part 1: Consecutive case study.

INTRODUCTION: Calcaneal pitch angle and Meary's angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. However, the methods used to obtain the talar, first metatarsal, calcaneal, and plantar axes differ across multiple reports, and no study has evaluated the reproducibility of these approaches. The aim of this study was to determine the most reproducible methods for radiographically evaluating longitudinal axes. METHODS: Standing radiographic images of 40 feet from 21 consecutive outpatients were obtained to measure longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. RESULTS: The best intraobserver and interobserver correlation coefficients for the talar, first metatarsal, and calcaneal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus, respectively. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach, although intraobserver and interobserver correlation coefficients could not be calculated because all values were zero. CONCLUSIONS: The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches. This study could contribute to more accurate assessments of foot deformities.

Total knee arthroplasty with corrective osteotomy for knee osteoarthritis associated with malunion after tibial plateau fracture: a case report.

BACKGROUND: When surgeons perform total knee arthroplasty in patients with knee osteoarthritis due to malunion following fractures around the knee joint, corrective osteotomy is recommended for severe deformities. Most such deformities are coronal plane varus or valgus deformities, and reports of sagittal plane flexion or extension deformities are rare. We describe a case in which a one-stage total knee arthroplasty was performed with extension corrective osteotomy in the sagittal plane. CASE PRESENTATION: A 71-year-old Japanese man presented with left knee pain. He had knee osteoarthritis associated with malunion after a tibial plateau fracture. Plain radiography showed a varus deformity in the coronal plane and a marked flexion deformity in the sagittal plane. We performed total knee arthroplasty concurrently with extension corrective osteotomy using a long stem. Full weight bearing was permitted at 6 weeks postoperatively, and the patient was able to walk without assistance. CONCLUSIONS: This surgical method appears to be beneficial for shortening the duration of treatment and improving knee function.

Spontaneous flexor tendon rupture due to an insufficiency fracture of the hamate hook in a patient with systemic lupus erythematosus: A case report.

INTRODUCTION: Spontaneous flexor tendon rupture is usually caused by trauma, systemic diseases, or carpal bone and joint disorders. Here we report a case of spontaneous flexor tendon rupture occurring in a systemic lupus erythematosus (SLE) patient following nonunion of the hamate hook after an insufficiency fracture, and which was also associated with tendon degeneration caused by SLE. CASE PRESENTATION: A 57-year-old woman was diagnosed with SLE 22 years ago and being treated with oral prednisolone. She became unable to flex her left little finger without any history of trauma or sporting activity. CT showed nonunion of the hamate hook. MRI showed rupture of the flexor digitorum profundus tendon of the little finger. We performed tendon transfer and excision of the hamate hook. She recovered active flexion of the little finger at 4 months postoperatively with full satisfaction. DISCUSSION: There was no history of trauma that could have caused nonunion of the hamate hook. We considered that the insufficiency fracture of the hamate hook occurred as a result of osteoporosis caused by SLE and long-term steroid use. Nonunion of the hamate hook caused mechanical attrition of the tendons, and in combination with the tendon degeneration caused by SLE, further resulted in rupture of the flexor tendon. CONCLUSION: When we encounter a case of spontaneous flexor tendon rupture in a patient with systemic disease such as SLE or long-term steroid use, attention should be paid to the state of the carpal bones and joints as they sometimes accompany unexpected causes.

A PTH-responsive circadian clock operates in ex vivo mouse femur fracture healing site.

The circadian clock contains clock genes including Bmal1 and Period2, and it maintains an interval rhythm of approximately 24 hours (the circadian rhythm) in various organs including growth plate and articular cartilage. As endochondral ossification is involved not only in growth plate but also in fracture healing, we investigated the circadian clock functions in fracture sites undergoing healing. Our fracture models using external fixation involved femurs of Period2::Luciferase knock-in mice which enables the monitoring of endogenous circadian clock state via bioluminescence. Organ culture was performed by collecting femurs, and fracture sites were observed using bioluminescence imaging systems. Clear bioluminescence rhythms of 24-hour intervals were revealed in fracture healing sites. When parathyroid hormone (PTH) was administered to fractured femurs in organ culture, peak time of Period2::Luciferase activity in fracture sites and growth plates changed, indicating that PTH-responsive circadian clock functions in the mouse femur fracture healing site. While PTH is widely used in treating osteoporosis, many studies have reported that it contributes to improvement of fracture healing. Future studies of the role of this local clock in wound healing may reveal a novel function of the circadian timing mechanism in skeletal cells.

Effect of Multiple Clock Gene Ablations on the Circadian Period Length and Temperature Compensation in Mammalian Cells.

Most organisms have cell-autonomous circadian clocks to coordinate their activity and physiology according to 24-h environmental changes. Despite recent progress in circadian studies, it is not fully understood how the period length and the robustness of mammalian circadian rhythms are determined. In this study, we established a series of mouse embryonic stem cell (ESC) lines with single or multiplex clock gene ablations using the CRISPR/Cas9-based genome editing method. ESC-based in vitro circadian clock formation assay shows that the CRISPR-mediated clock gene disruption not only reproduces the intrinsic circadian molecular rhythms of previously reported mice tissues and cells lacking clock genes but also reveals that complexed mutations, such as CKIδ(m/m):CKIε(+/m):Cry2(m/m) mutants, exhibit an additively lengthened circadian period. By using these mutant cells, we also investigated the relation between period length alteration and temperature compensation. Although CKIδ-deficient cells slightly affected the temperature insensitivity of period length, we demonstrated that the temperature compensation property is largely maintained in all mutants. These results show that the ESC-based assay system could offer a more systematic and comprehensive approach to the genotype-chronotype analysis of the intracellular circadian clockwork in mammals.

Parathyroid hormone resets the cartilage circadian clock of the organ-cultured murine femur.

BACKGROUND AND PURPOSE: The circadian clock governs endogenous day-night variations. In bone, the metabolism and growth show diurnal rhythms. The circadian clock is based on a transcription-translation feedback loop composed of clock genes including Period2 (Per2), which encodes the protein period circadian protein homolog 2. Because plasma parathyroid hormone (PTH) levels show diurnal variation, we hypothesized that PTH could carry the time information to bone and cartilage. In this study, we analyzed the effect of PTH on the circadian clock of the femur. PATIENTS AND METHODS: Per2::Luciferase (Per2::Luc) knock-in mice were used and their femurs were organ-cultured. The bioluminescence was measured using photomultiplier tube-based real-time bioluminescence monitoring equipment or real-time bioluminescence microscopic imaging devices. PTH or its vehicle was administered and the phase shifts were calculated. Immunohistochemistry was performed to detect PTH type 1 receptor (PTH1R) expression. RESULTS: Real-time bioluminescence monitoring revealed that PTH reset the circadian rhythm of the Per2::Luc activity in the femurs in an administration time-dependent and dose-dependent manner. Microscopic bioluminescence imaging revealed that Per2::Luc activity in the growth plate and the articular cartilage showed that the circadian rhythms and their phase shifts were induced by PTH. PTH1R was expressed in the growth plate cartilage. INTERPRETATION: In clinical practice, teriparatide (PTH (1-34)) treatment is widely used for osteoporosis. We found that PTH administration regulated the femoral circadian clock oscillation, particularly in the cartilage. Regulation of the local circadian clock by PTH may lead to a more effective treatment for not only osteoporosis but also endochondral ossification in bone growth and fracture repair.

Robust Circadian Rhythm and Parathyroid Hormone-Induced Resetting during Hypertrophic Differentiation in ATDC5 Chondroprogenitor Cells.

Cartilage tissues possess intrinsic circadian oscillators, which influence chondrocyte function and chondrocyte specific gene expression. However, it is not fully understood how chondrogenesis influences the circadian clock, and vice versa. Thus, we established ATDC5 cells which were stably transfected with the Bmal1:luc reporter and revealed robust circadian rhythms in ATDC5 cells during differentiation. Moreover, the circadian clock in ATDC5 cells was strongly reset by PTH in a circadian time-dependent manner. This assay system is expected to be useful for investigating the role of the circadian clock in chondrogenic differentiation and the precise molecular mechanisms underlying PTH action on the chondrocyte circadian clock.