Total hip arthroplasty after rotational acetabular osteotomy for developmental dysplasia of the hip: a retrospective observational study.

BACKGROUND: Total hip arthroplasty after osteotomy is more technically challenging than primary total hip arthroplasty, especially concerning cup placement. This is attributed to bone morphological abnormalities caused by acetabular bone loss and osteophyte formation. This study aimed to investigate the clinical and radiological outcomes of total hip arthroplasty after rotational acetabular osteotomy compared with those of primary total hip arthroplasty, focusing mainly on acetabular deformity and cup position. METHODS: The study included 22 hips that had undergone rotational acetabular osteotomy and 22 hips in an age- and sex-matched control group of patients who underwent total hip arthroplasties between 2005 and 2020. We analyzed cup abduction and anteversion; lateral, anterior, and posterior cup center-edge angle; hip joint center position; femoral anteversion angle; and presence of acetabular defect using postoperative radiography and computed tomography. Operative results and clinical evaluations were also analyzed. RESULTS: The clinical evaluation showed that the postoperative flexion range of motion was lower in total hip arthroplasty after rotational acetabular osteotomy than in primary total hip arthroplasty, although no significant difference was noted in the postoperative total Japanese Orthopedic Association hip score. The operative time was significantly longer in the rotational acetabular osteotomy group than in the control group, but there was no significant difference in blood loss. The lateral cup center-edge angle was significantly higher and the posterior cup center-edge angle was significantly lower in the total hip arthroplasty after rotational acetabular osteotomy, suggesting a posterior bone defect existed in the acetabulum. In total hip arthroplasty after rotational acetabular osteotomy, the hip joint center was located significantly superior and lateral to the primary total hip arthroplasty. CONCLUSIONS: In total hip arthroplasty after rotational acetabular osteotomy, the cup tended to be placed in the superior and lateral positions, where there was more bone volume. The deformity of the acetabulum and the high hip center should be considered for treatment success because they may cause cup instability, limited range of motion, and impingement.

Eccentric Rotational Acetabular Osteotomy Using Computed Navigation Guidance for Developmental Dysplasia of the Hip, Sacroiliac Fusion, and Femoroacetabular Impingement Owing to Acetabular Retroversion: A Case Report.

BACKGROUND: Developmental dysplasia of the hip (DDH) is the main factor that causes secondary osteoarthritis of the hip (hip OA). Acetabular retroversion results in pincer-type femoroacetabular impingement (FAI), and this is also known to cause secondary hip OA. However, few cases of DDH with acetabular retroversion have been reported, and there is no definite opinion on the optimal treatment. We report a rare case of DDH and FAI owing to acetabular retroversion and dysostosis of the sacroiliac joint that was treated with eccentric acetabular rotational osteotomy (ERAO) using navigation guidance. CASE PRESENTATION: A 27-year-old woman presented with DDH and acetabular retroversion with FAI and dysostosis of the sacroiliac joint on the contralateral side. We performed ERAO using computed navigation guidance and improved the coverage and retroversion of the acetabulum. The acetabular anteversion angle improved from 1° retroversion to 9° anteversion after surgery, the center edge angle improved from 18° to 43°, and the acetabular head index improved from 69% to 93%. The cam lesion of the femur was resected. The Harris Hip Score improved from 55.7 to 100 points at the final examination 2 years after surgery. CONCLUSIONS: In this rare case of DDH and FAI, ERAO using computed navigation guidance accurately improved the coverage and retroversion of the acetabulum.

Prosthetic joint infection after total hip arthroplasty caused by Sneathia sanguinegens: A case report (CARE-complaint).

INTRODUCTION: Sneathia sanguinegens(S sanguinegens) is a gram-negative rod-shaped bacterium mostly reported to cause a perinatal infection, and there are no reports of S sanguinegens in prosthetic joint infection (PJI). The purpose of this report is to describe a very rare case of PJI after total hip arthroplasty (THA) caused by S sanguinegens. PATIENT CONCERNS: A 79-year-old woman presented with right coxalgia, inability to walk, and a fever of 39°C. She had undergone THA 28 years earlier for osteoarthritis of the hip. DIAGNOSES: The diagnosis was acute late-onset PJI, because blood tests revealed marked inflammatory reaction and computed tomography showed an abscess at the right hip joint; synovial fluid analysis resulted in detection of a gram-negative bacillus. INTERVENTION: Surgical debridement with retention of the implant and antibiotic therapy was performed. OUTCOMES: One month after surgery, polymerase chain reaction (PCR) assay showed that the pathogen was 99.9% likely to be S sanguinegens. There has been no recurrence of infection or loosening of the implant in the 2 years since her surgery. LESSONS: PCR should facilitate detection of previously unknown pathogens and potentially novel bacterial species.

Fracture of the Femoral Component Caused by Insufficient Crimping after Modern Unicompartmental Knee Arthroplasty.

Fracture of a femoral component after modern unicompartmental knee arthroplasty is very rare. Although this is not the first case on this subject, no study has reported insufficient crimping as the cause of femoral component loosening that led to breakage of a metallic component. A 69-year-old man underwent medial unicompartmental knee arthroplasty for right medial knee osteoarthritis. His early postoperative course was good; however, the 1-year postoperative radiograph showed an apparent radiolucent line around the femoral component, and he occasionally had right knee pain. However, he had been followed up conservatively because he had been doing well even while doing heavy agricultural work. At 8 years after surgery, because breakage of the femoral component was found, revision surgery was performed using bicruciate-retaining total knee arthroplasty. The removed fractured femoral component revealed a thick cement mantle detached from the bone surface. The postoperative course of the patient after the revision surgery was excellent. We suggest that the causes of femoral component breakage include early implant loosening caused by uneven cement crimping of the femoral component to the bone and excessive loading stress as a result of heavy labour.

Accumulation of microdamage and low bone mass in the femoral head as a cause of subchondral insufficiency fracture in a patient with osteogenesis imperfecta.

Subchondral insufficiency fractures of the femoral head are generally considered to be osteoporosis-related fragility fractures. There have been reports of microfractures being found in subchondral bone on pathological examination. However, the mechanism of these microfractures is not known. In this report, we describe a patient with osteogenesis imperfecta who developed a subchondral insufficiency fracture of the femoral head after a fall that had resulted in a subcapital femoral neck fracture. Bipolar hemiarthroplasty was performed, and bone at the femoral head and neck was sampled for pathophysiological examination. Hematoxylin and eosin staining revealed microfractures and microcallus in the subchondral bone in the femoral head, indicating healing of a subchondral insufficiency fracture before the subcapital femoral neck fracture. Moreover, decreased bone volume and accumulated microdamage were observed in the subchondral bone but not in the cancellous bone in the femoral neck. These findings suggest that subchondral insufficiency fracture of the femoral head is a stress fracture caused by accumulation of microdamage in fragile subchondral bone.

Accumulation of microdamage in subchondral bone at the femoral head in patients with end-stage osteoarthritis of the hip.

In end-stage osteoarthritis (OA) of the hip, the effect of bone metabolism with and without cartilage is unclear. In this study, we aimed to investigate histomorphology and microdamage in the subchondral bone of the femoral head in areas with and without articular cartilage in patients with end-stage OA. Nineteen femoral heads were evaluated in 10 women who underwent total hip arthroplasty for OA and in nine cadaveric controls (CNT). Chondral thickness and subchondral bone plate thickness (SBP.Th) were measured in 5-mm-wide areas where cartilage was lost (area A) or preserved (area B) in OA and in corresponding areas in the load-bearing portion of the femoral head in the CNT. Histomorphometry and microdamage in 5 × 5-mm areas of cancellous bone were assessed. SBP.Th and bone volume were significantly greater in area A than in area B or in the CNT. Osteoid volume was significantly greater in area A than in area B or in the CNT. There was no significant difference in eroded surface between area A and CNT. Microcrack density was significantly greater in area A than in area B or in the CNT. Although accumulation of microdamage was caused by concentration of stress on the subchondral bone in the cartilage loss area in end-stage OA, remodeling for microdamage repairing mechanism was not enhanced. It was considered that the subchondral cancellous bone volume was increased because of modeling, not remodeling, by stress concentration due to articular cartilage loss.

Weekly teriparatide treatment increases vertebral body strength by improving cortical shell architecture in ovariectomized cynomolgus monkeys.

Weekly teriparatide treatment is reported to reduce the incidence of osteoporotic vertebral fractures. However, the effect of weekly teriparatide on cortical bone has not been clarified. This study aimed to examine the effects of weekly teriparatide treatment on bone mass, intracortical structure, and remodeling of the lumbar vertebral cortical shell and its relation to mechanical properties in ovariectomized cynomolgus monkeys. Female monkeys, aged 9 to 15 years, were divided into four groups: (1) SHAM group, (2) ovariectomized group (OVX group), (3) OVX with 1.2 µg/kg once-weekly teriparatide group (LOW group), (4) OVX with 6.0 µg/kg once-weekly teriparatide group (HIGH group). After 18 months, all animals were double-labeled with calcein, and lumbar vertebrae were analyzed with histomorphometry and compressive mechanical tests. Following ovariectomy, we found reductions in the anterior cortical shell area of the vertebrae and reductions in nearly all of the tested vertebral mechanical properties. Weekly teriparatide significantly preserved the anterior cortical shell area and the energy absorption capacity of the lumbar vertebrae in a dose-dependent manner. Multiple regression analyses indicated that improved mechanical properties were more associated with the increased anterior cortical shell area rather than the cancellous bone volume. The intracortical structure of the Haversian canals was also preserved following teriparatide treatment after ovariectomy. These findings suggest the importance of the cortical shell as a therapeutic target in the treatment of osteoporosis. Weekly teriparatide treatment increases the compressive mechanical strength of the lumbar vertebrae by thickening the anterior cortical shell.

Once-Weekly Teriparatide Treatment Prevents Microdamage Accumulation in the Lumbar Vertebral Trabecular Bone of Ovariectomized Cynomolgus Monkeys.

The effect of teriparatide treatment on microdamage accumulation has yet to be examined in animal studies. The purpose of this study was to investigate the effect of once-weekly teriparatide treatment on bone microdamage accumulation and the relationship between microdamage parameters and bone mass, architecture, turnover, and collagen cross-linking in the lumbar vertebral trabecular bone of ovariectomized (OVX) cynomolgus monkeys. Female monkeys were divided into four groups (n = 18-20 per group): (1) SHAM group, (2) OVX group, (3) OVX with 1.2 µg/kg once-weekly teriparatide group (LOW group), (4) OVX with 6.0 µg/kg once-weekly teriparatide group (HIGH group). After 18 months, all animals were double-labeled with calcein for histomorphometry. L3 and L7 lumbar vertebrae were harvested and analyzed for differences in histomorphometry, microdamage, and collagen cross-linking. The iliac crest was also analyzed for differences in bone turnover. In the OVX group, cancellous bone mass was reduced and microdamage accumulation was increased as compared with the SHAM control. Once-weekly teriparatide at both doses prevented the decrease in bone mass and increase in microdamage accumulation, and improved the distribution of collagen cross-linkage types. Regression analyses indicated that decreased microdamage accumulation was associated with reduced non-enzymatic cross-link pentosidine rather than increased cancellous bone mass or enzymatic cross-links. These findings suggest that once-weekly teriparatide treatment decreases microdamage accumulation by recovering the balance in collagen cross-links.

Treatment status and radiographic features of patients with atypical femoral fractures.

BACKGROUND: The Japanese Orthopaedic Association (JOA) has been surveying approximately 3000 orthopedic surgery hospitals and clinics with inpatient facilities nationwide to collect information on atypical femoral fractures (AFFs) and patient characteristics since 2010. The present study aims to examine radiographic images and clarify the relationship between radiographic and patient characteristics of patients with AFF and treatment status. METHODS: The study involved 1996 facilities certified as clinical training sites by the JOA and 912 clinics with inpatient facilities affiliated with the Japanese Clinical Orthopaedic Association (JCOA). Additional clinical data collection and radiographic image review were performed in patients aged 35 years or older who met the American Society for Bone and Mineral Research (ASBMR) case definition for AFF and received treatment at participating facilities registered with JOA in 2013. Radiographic images were evaluated in accordance with the ASBMR case definition. RESULTS: Radiographic images of 304 fractures in 304 patients were collected. Among them, 230 fractures were determined to be AFFs. The fracture site was the proximal third in 70 AFFs (30.4%), middle third in 157 AFFs (68.3%), and distal third in 3 AFFs (1.3%). Among patients with AFFs, 173 (75.2%) were treated with bisphosphonates (BPs) and 45 patients (19.6%) were not (unknown in 12 patients). Duration of use was three years or longer in 103 patients (59.5%) and between one and three years in 24 patients (13.9%). Radiographic beaking was observed in 149 fractures (86.1%) in patients treated with BPs and 17 fractures (37.8%) in patients who were not treated with BPs (odds ratio 11.3, 95% CI 5.7-22.3). CONCLUSIONS: Radiographic beaking was observed more frequently in patients treated with BPs than in patients not treated with BPs.

Survey of hip fractures in Japan: Recent trends in prevalence and treatment.

BACKGROUND: A nationwide survey of hip fractures by the Japanese Orthopaedic Association (JOA) from 1998 to 2008 found a drastic increase in incidence. The aims of this study were to elucidate the status of hip fractures from 2009 to 2014 and to survey the causes for delayed surgery. METHODS: A tally of all hip fractures that occurred in patients from 2009 to 2014 was conducted in hospitals authorized by the JOA or in clinics with inpatient facilities of the Japanese Clinical Orthopaedic Association (JCOA). A survey of the causes for delay in surgery was conducted at 849 sites and 526 sites participated. RESULTS: A total of 488,759 hip fractures were registered. Increases in incidence from 2009 to 2014 were prominent in the 90-94-year-old age group among women and the 85-89-year-old age group among men. More trochanteric fractures than neck fractures occurred; however, the neck/trochanter ratio increased over time. The mean duration of preoperative hospital stay was 4.8 and 4.5 days, and the mean duration of hospitalization was 40.5 and 36.8 days in 2009 and 2014, respectively. There were significant differences between patients who waited for surgery up to 3 days and those who waited longer than 3 days in date of hospitalization, fracture type, comorbidities, anticoagulant use, surgical procedure, type of physician who administered anesthesia, type of anesthesia, and operating room schedule. Physicians in charge of each patient who waited for surgery for more than 3 days most frequently cited difficulties in securing operating rooms as the cause for delayed surgery. CONCLUSION: A drastic increase occurred in the number of patients with hip fractures with time in Japan. One problem in the treatment of hip fractures is the long waiting time from hospitalization to surgery resulting from difficulties in securing operating rooms.

Effects of suppressed bone remodeling by minodronic acid and alendronate on bone mass, microdamage accumulation, collagen crosslinks and bone mechanical properties in the lumbar vertebra of ovariectomized cynomolgus monkeys.

Collagen crosslinking is an important determinant of the quality of bone material. We have previously shown that suppressed bone turnover by high doses of minodronic acid and alendronate increases compressive strength of vertebra, but also increases microdamage accumulation, in monkey bone. The aim of this study is to examine the effects of these bisphosphonates on collagen crosslinks and intrinsic material properties, in addition to microdamage accumulation, in vertebral cancellous bone in ovariectomized cynomolgus monkeys. Sixty female monkeys aged 9-17years were divided into five groups: sham and ovariectomized groups were treated daily for 17months with lactose vehicle, and the other three groups were given minodronic acid daily at 0.015 or 0.15mg/kg or alendronate daily at 0.5mg/kg orally. After sacrifice, lumbar vertebrae were subjected to histomorphometry, microdamage measurement, analysis of collagen crosslinking and compressive mechanical tests. Minodronic acid caused dose-dependent suppression of increased bone remodeling due to ovariectomy, and low-dose minodronic acid suppressed remodeling same level as alendronate. However, low-dose minodronic acid did not change microdamage accumulation, collagen maturity and the pentosidine level, whereas high-dose minodronic acid and alendronate increased these parameters. Compressive ultimate load was increased following high-dose minodronic acid and alendronate, but no treatment altered the reduction in intrinsic material properties caused by ovariectomy. These findings suggest that deterioration of bone material and formation of pentosidine and microdamage induced by minodronic acid is less than that expected based on the extent of remodeling suppression, in comparison with alendronate, but this was not reflected in any significant change of mechanical properties.

Minodronic acid ameliorates vertebral bone strength by increasing bone mineral density in 9-month treatment of ovariectomized cynomolgus monkeys.

The effect of treatment for 9months with minodronic acid, a nitrogen-containing bisphosphonate, on vertebral mechanical strength was examined in ovariectomized (OVX) cynomolgus monkeys. Forty skeletally mature female monkeys were randomized into four OVX groups and one sham group (n=8) based on lumbar bone mineral density (BMD). OVX animals were treated orally with 15 and 150µg/kg QD of minodronic acid or 500µg/kg QD alendronate as a reference drug. Measurements of bone turnover markers and lumbar BMD were conducted at 0, 4 and 8months. Measurements of bone mechanical strength and minodronic acid concentration in vertebral bodies were also performed. OVX resulted in a decrease in lumbar BMD and an increase in bone turnover markers at 4 and 8months, compared to the sham group, and the ultimate load on the lumbar vertebra was decreased in OVX animals. Minodronic acid and alendronate prevented the OVX-induced increase in bone turnover markers and decrease in lumbar BMD. Minodronic acid at 150µg/kg increased the ultimate load on lumbar vertebra compared to untreated OVX animals. Regression analysis revealed that the ultimate load was correlated with lumbar BMD and bone mineral content (BMC), and most strongly with the increase in lumbar BMD and BMC over 8months. In a separate analysis within the sham-OVX controls and minodronic acid and alendronate treatment groups, the ultimate loads were also correlated with BMD and BMC. The load-BMD (BMC) correlation in the minodronic acid group showed a trend for a shift to a higher load from the basal relationship in the sham-OVX controls. These results indicate that treatment with minodronic acid for 9months increases vertebral mechanical strength in OVX monkeys, mainly by increasing BMD and BMC.

[Evaluation of bone sterngth].

Biomechanical testing of the bone provides the most important and direct information about bone strength. This article explains biomechanical priciples including structural mechanical properties and intrinsic material properties, and serves actual biomechanical testing tedhniques for bone specimens.

[Pathogenesis of atypical femoral fracture].

We demonstrated microdamage accumulation in the fracture sites in the patients of subtrochanteric atypical femoral fracture with long term bisphosphonate therapy and of incomplete shaft fracture of lateral femoral bowing without bisphosphonate therapy. Based on these findings, pathogenesis of atypical femoral fracture is revealed stress fracture caused by accumulation of microdamages between distal to the lesser trochanter and proximal to the supracondylar flare in the femur in association with severely suppressed bone turnover and/or abnormal lower limb alignment, that causes stress concentration on the lateral side cortex of the femur.

[Bone Cell Biology Assessed by Microscopic Approach. The effects of bisphosphonates on bone remodeling, microdamage accumulation and fracture repair process].

Basically bisphosphonates are the agents that prevent the deterioration of bone structure due to suppressed bone remodeling although they are able to increase the thickness of cortical bone by suppressing bone resorption in the cortical surfaces. On the other hand, suppression of bone remodeling allows microdamage accumulation by impaired repair of damages, therefore, severe remodeling suppression over long time period could promote bone fatigue process, leading to fatigue fractures such as atypical femoral fracture. The use of bisphosphonate after fracture may delays natural fracture healing process due to suppressed callus remodeling. Bisphosphonate that has high binding affinity to bone easily accumulates in bone, therefore, easily causes severely suppressed bone turnover following long term treatment, and its effects last longer even after withdrawal.

A large amount of microdamages in the cortical bone around fracture site in a patient of atypical femoral fracture after long-term bisphosphonate therapy.

A breast cancer patient developed an atypical femoral fracture after 9 years of bisphosphonate therapy for the treatment of multiple bone metastases. We histopathologically analyzed the femoral cortical bone at the fracture site and the iliac cancellous bone. Four months prior to the fracture, the patient had experienced pain in the right femur and underwent plain radiography and bone scintigraphy which revealed cortical thickening and radioisotope accumulation at each site, respectively. The patient had also experienced a non-traumatic fracture at the same site on the contralateral side 2 years earlier. Based on these findings, atypical femoral fracture was diagnosed and intramedullary nailing performed. A cortical bone specimen taken from near the fracture site during surgery showed marked microdamages, and analysis of the iliac cancellous bone specimen revealed severely suppressed bone turnover. These findings suggest that microdamage and severely suppressed bone turnover are associated with atypical femoral fracture reported in this patient with long-term bisphosphonate therapy.

Effects of minodronic acid and alendronate on bone remodeling, microdamage accumulation, degree of mineralization and bone mechanical properties in ovariectomized cynomolgus monkeys.

Suppression of bone remodeling by bisphosphonates leads to accumulation of microdamage in bone. If this microdamage develops due to suppressed repair of remodeling only, more potent bisphosphonates should cause more damage. In this study, we evaluated the effects of reduced bone turnover produced by a potent bisphosphonate, minodronic acid, on microdamage accumulation, the degree of mineralization and mechanical properties of bone in ovariectomized cynomolgus monkeys, and compared these effects with those of alendronate. Sixty female monkeys aged 9-17 years old were divided into five groups. The sham group and the ovariectomized group were treated daily for 17 months with lactose vehicle. The other three groups were treated daily with minodronic acid at a dose of 0.015 mg/kg or 0.15 mg/kg, or alendronate at 0.5mg/kg orally. After sacrifice, lumbar vertebrae and left femurs were subjected to histomorphometry, microdamage, mineralization analyses, and mechanical testing. Minodronic acid suppressed bone remodeling of cancellous and cortical bone in a dose-dependent manner and the higher dose of minodronic acid suppressed bone remodeling more strongly than alendronate. The lower dose of minodronic acid did not increase microdamage accumulation and compressive strength, but the higher dose of minodronic acid and alendronate resulted in similar increases in cancellous microdamage accumulation and ultimate load in lumbar vertebra. There were no significant differences among the groups in microdamage, degree of mineralization and mechanical properties in cortical bone of the femoral shaft; however, only alendronate showed a tendency to increase highly mineralized osteons and microdamage. These findings suggest that microdamage caused by minodronic acid is less than that expected based on the extent of remodeling suppression, in comparison with alendronate although this was not reflected in any significant change of mechanical properties.

[Is SSBT associated with atypical femoral fracture? SSBT is associated with atypical femoral fracture - pathophysiology of atypical femoral fractures - ].

Recently, atypical femoral fracture has emerged as potential complication of long-term bisphosphonate therapy. Before considering the potential harmful effects of oversupression of bone turnover, it has been supposed that suppressed bone turnover in postmenopausal skeleton has well documented beneficial effects on bone strength and fracture risk. However, the benefit of long-term use of bisphosphonate for the prevention of femoral fractures seems to be lower than previously speculated. There are several factors by which severely suppressed bone turnover may reduce bone mechanical properties. These include increased mineralization of bone and increased homogeneity of mineralization, changes in collagen cross linking and accumulation of bone microdamage.

Effect of dosing interval duration of intermittent ibandronate treatment on the healing process of femoral osteotomy in a rat fracture model.

The effects of bisphosphonate treatment schedule on fracture healing have not previously been tested. We evaluated the effect of ibandronate dosing interval duration on healing following surgical "fracture" (osteotomy) using a rat femoral fracture model. Six-week-old rats (n = 160) underwent osteotomy and were then allocated into vehicle control (CNT) or an ibandronate treatment group: 5 µg/kg daily (DAY, 5 days/week), 75 µg/kg once every 3 weeks (I-3), 150 µg/kg once every 6 weeks (I-6), resulting in the same total ibandronate dose over the study. Rats were killed after 6 or 18 weeks. At 18 weeks, all fracture lines had disappeared in the CNT and I-6 groups; approximately 10% of fracture lines remained in the DAY and I-3 groups. Ibandronate-treated groups showed large callus areas around the fractures, which shrank between 6 and 18 weeks after surgery; the extent of shrinkage decreased with shorter dosing interval. In histomorphometry, callus remodeling was suppressed by ibandronate; this became more apparent at shorter dose intervals. The structural properties of osteotomized femora were increased in the DAY group compared with CNT, but intrinsic material properties reduced inversely and became closer to those of CNT in response to increased dosing interval. Ibandronate induced formation of large calluses around osteotomies but delayed woven bone remodeling into lamellar bone and reduced intrinsic material properties in a rat fracture model. Extending the dosing interval of intermittent ibandronate treatment appeared to reduce the suppression of callus remodeling caused by ibandronate, which would have delayed healing after osteotomy.