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Purpose: Although good mid-term results of the first- and second-generation cementless stems have been reported, no study has compared outcomes between generations. This study aimed to compare the mid-term results of Accolade Ti–12Mo–6Zr–2Fe (TMZF) and Accolade II over a 5-year period. Methods: This retrospective, single-institution, single-surgeon observational study included patients who underwent primary total hip arthroplasty using the Accolade TMZF (n ​= ​71, group I) or Accolade II (n ​= ​73, group II) between January 2009 and July 2015. Revision and conversion cases were excluded. Functional evaluations were performed using the Japanese Orthopaedic Association hip (JOA) score. Radiographic evaluations were performed using anteroposterior radiographs. Spot welds, radiolucency, cortical hypertrophy, and stress shielding around the stem were assessed for each Gruen zone. Subsidence and stem alignment were evaluated. Results: The 5-year postoperative stem survival rate was 100% in both groups. The JOA score improved from 44.0 ​± ​10.2 to 90.6 ​± ​7.6 in group I and from 49.1 ​± ​10.1 to 91.7 ​± ​6.6 in group II. There were no significant differences in preoperative and postoperative JOA scores and subscale scores in either group. Significant spot welds were observed in group II in Gruen zones 3 and 5. Stress shielding progressed over time in both groups, and the prevalence of grade 3 shielding was significantly lower in group II (p ​= ​0.028). Conclusion: Both stems had a survival rate of 100%. The incidence of severe stress shielding seemed to be lower with Accolade II, but further investigations should be needed.

Abstract Background Perioperative greater trochanteric fracture following total hip arthroplasty (THA) using the anterolateral approach is a recognized perioperative complication. There was no previous study to determine the relationship between bone mineral density (BMD) and three-dimensional greater trochanter morphology for perioperative greater trochanter fractures. The purpose of this study is to identify the influence of greater trochanteric bone density and three-dimensional morphology on perioperative greater trochanteric fracture following THA using the anterolateral approach. Methods We investigated 209 hips done primary THA using the anterolateral approach and preoperative BMD test for the proximal femoral bone with a minimum of 6 months follow-up. We picked up all patients who had perioperative greater trochanteric fractures. Multivariate analysis was done in order to investigate the influence of the greater trochanter young adult mean (YAM) and three-dimensional morphology on perioperative greater trochanteric fractures. Results There were 10 joints (10/209, 4.8%) with perioperative greater trochanteric fractures. Osteosynthesis was required only in one joint (1/209, 0.5%) because the bone fragments were significantly displaced proximally by the gluteus medius. Multivariate analysis showed the combination of Type B femoral shape (in cases where the top of the great trochanter was inside the longitudinal central axis of the planned femoral stem in computed tomography (CT)- based three-dimensional templating) and a YAM of

Abstract Periprosthetic joint infection (PJI) is characterized by biofilm infection, which is difficult to alleviate while preserving implant integrity. Furthermore, long-term antibiotic therapy may increase the prevalence of drug-resistant bacterial strains, necessitating a non-antibacterial approach. Adipose-derived stem cells (ADSCs) exert antibacterial effects; however, their efficacy in PJI remains unclear. This study investigates the efficacy of combined intravenous ADSCs and antibiotic therapy in comparison to antibiotic monotherapy in a methicillin-sensitive Staphylococcus aureus (MSSA)-infected PJI rat model. The rats were randomly assigned and equally divided into 3 groups: no-treatment group, antibiotic group, ADSCs with antibiotic group. The ADSCs with antibiotic group exhibited the fastest recovery from weight loss, with lower bacterial counts (p = 0.013 vs. no-treatment group; p = 0.024 vs. antibiotic group) and less bone density loss around the implants (p = 0.015 vs. no-treatment group; p = 0.025 vs. antibiotic group). The modified Rissing score was used to evaluate localized infection on postoperative day 14 and was the lowest in the ADSCs with antibiotic group; however, no significant difference was observed between the antibiotic group and ADSCs with antibiotic group (p < 0.001 vs. no-treatment group; p = 0.359 vs. antibiotic group). Histological analysis revealed a clear, thin, and continuous bony envelope, a homogeneous bone marrow, and a defined, normal interface in the ADSCs with antibiotic group. Moreover, the expression of cathelicidin expression was significantly higher (p = 0.002 vs. no-treatment group; p = 0.049 vs. antibiotic group), whereas that of tumor necrosis factor (TNF)-α and interleukin(IL)-6 was lower in the ADSCs with antibiotic group than in the no-treatment group (TNF-α, p = 0.010 vs. no-treatment group; IL-6, p = 0.010 vs. no-treatment group). Thus, the combined intravenous ADSCs and antibiotic therapy induced a stronger antibacterial effect than antibiotic monotherapy in a MSSA-infected PJI rat model. This strong antibacterial effect may be related to the increased cathelicidin expression and decreased inflammatory cytokine expression at the site of infection.

Abstract We aimed to assess the reliability and validity of OpenPose, a posture estimation algorithm, for measuring hip-knee-ankle (HKA) angle in patients with knee osteoarthritis, by comparing it with radiography. In this prospective study, we analysed 60 knees (30 patients) with knee osteoarthritis. We measured HKA angle using OpenPose and radiography before or after total knee arthroplasty and assessed the test–retest reliability of each method with intraclass correlation coefficient (1, 1). We evaluated the ability to estimate the radiographic measurement values from the OpenPose values using linear regression analysis and used intraclass correlation coefficients (2, 1) and Bland–Altman analyses to evaluate the agreement and error between OpenPose and radiographic measurements. OpenPose had excellent test–retest reliability (intraclass correlation coefficient (1, 1) = 1.000) and excellent agreement with radiography (intraclass correlation coefficient (2, 1) = 0.915), with regression analysis indicating a large correlation (R2 = 0.865). OpenPose also had a 1.1° fixed error and no systematic error when compared with radiography. This is the first study to validate the use of OpenPose for the estimation of HKA angle in patients with knee osteoarthritis. OpenPose is a reliable and valid tool for measuring HKA angle in patients with knee osteoarthritis. OpenPose, which enables non-invasive and simple measurements, may be a useful tool to assess changes in HKA angle and monitor the progression and post-operative course of knee osteoarthritis. Furthermore, this validated tool can be used not only in clinics and hospitals, but also at home and in training gyms; thus, its use could potentially be expanded to include self-assessment/monitoring.

Abstract Background A chronic expanding hematoma (CEH) is a rare complication caused by surgery or trauma; it mostly affects the soft tissues, such as those in the trunk or extremities. We present the first case of a large intraosseous CEH presenting with chronic disseminated intravascular coagulation (DIC), 22 years after total hip arthroplasty (THA); the CEH was treated with a single-stage excision and revision THA. Case presentation A 67-year-old man presented to our hospital with left thigh pain and an enlarging mass. He had no history of trauma, anticoagulant use, or a collagen vascular disorder. The patient initially declined surgery. Two years later, radiographs and computed tomography images revealed progressive osteolysis, marginal sclerosis, and calcification in the left femur, in addition to loosening of the femoral component. Laboratory data revealed anemia and chronic DIC of unknown causes. Magnetic resonance imaging revealed a “mosaic sign” on the mass, indicating a mix of low- and high-signal intensities on T2-weighted images. Needle biopsy prior to surgery revealed no infection or malignant findings. An intraosseous CEH was suspected due to extensive osteolysis and loosening of the femoral component. No other factors that could induce chronic DIC were identified, such as sepsis, leukemia, cancer, trauma, liver disease, aneurysms, or hemangiomas. Therefore, we speculated that the anemia and chronic DIC were caused by the large intraosseous CEH. A single-stage revision THA with surgical excision was performed to preserve the hip function and improve the chronic DIC. The postoperative histopathological findings were consistent with an intraosseous CEH. The anemia and chronic DIC improved after 7 days. There was no recurrence of intraosseous CEH or chronic DIC at the 6-month follow-up. The left thigh pain improved, and the patient could ambulate with the assistance of a walking frame. Conclusions The loosening of the femoral component caused persistent movement, which may have caused intraosseous CEH growth, anemia, and chronic DIC. It is important to differentiate CEHs from malignant tumors with hematomas. Furthermore, the “mosaic sign” noted in this case has also been observed on magnetic resonance images in other cases of CEH.

Adipose-derived stem cells (ADSCs) have been studied for many years as a therapeutic option for osteoarthritis (OA); however, their efficacy remains insufficient. Since platelet-rich plasma (PRP) induces chondrogenic differentiation in ADSCs and the formation of a sheet structure by ascorbic acid can increase the number of viable cells, we hypothesized that the injection of chondrogenic cell sheets combined with the effects of PRP and ascorbic acid may hinder the progression of OA. The effects of induction of differentiation by PRP and formation of sheet structure by ascorbic acid on changes in chondrocyte markers (collagen II, aggrecan, Sox9) in ADSCs were evaluated. Changes in mucopolysaccharide and VEGF-A secretion from cells injected intra-articularly in a rabbit OA model were also evaluated. ADSCs treated by PRP strongly chondrocyte markers, including type II collagen, Sox9, and aggrecan, and their gene expression was maintained even after sheet-like structure formation induced by ascorbic acid. In this rabbit OA model study, the inhibition of OA progression by intra-articular injection was improved by inducing chondrocyte differentiation with PRP and sheet structure formation with ascorbic acid in ADSCs.