Harmony between spinopelvic mismatch and sagittal hip alignment contributes to upright standing in females: a cross-sectional study.

Background: In upright standing, spinopelvic mismatch is compensated by hip extension. However, few studies have investigated the reciprocal relationship between the sagittal alignment of the hip joints and spinopelvic mismatch during upright standing in humans. Our study aims to investigate (I) the relationship between spinopelvic mismatch and hip extension and (II) whether insufficient hip extension against spinopelvic mismatch, i.e., pelvic incidence (PI)-lumbar lordosis (LL), affects trunk inclination in upright standing. Methods: This study was a retrospective cross-sectional study. We included 398 consecutive female patients treated for osteoporosis at our outpatient department between November 2017 and June 2022. Patients with any of the following were excluded from the study: (I) those whose plain whole-spine radiographs did not cover the femurs, (II) those with fractures in the vertebrae or lower extremities, (III) those with a history of surgery of the spine or of the lower extremities, (IV) those with scoliosis with a Cobb angle ≥10° in the anteroposterior radiograph, and (V) those with transitional vertebrae. Sixty-two patients were divided into normal and malalignment groups based on their sagittal spinal alignment. The patients underwent plain whole-spine radiography as a routine examination. A linear approximation between the pelvic femoral angle (PFA), representing hip extension, and PI-LL was obtained in both groups. The optimal PFA of each patient was obtained by substituting the PI-LL into the linear approximation of the normal group. The difference between the optimal and measured PFA was defined as the ΔPFA for each patient. The correlation between the ΔPFA and sagittal vertical axis (SVA) was evaluated in both groups. Results: The PFA and PI-LL were correlated in both groups. The malalignment group had a significantly greater ΔPFA than the normal group. ΔPFA was correlated with SVA only in the malalignment group. Conclusions: The magnitude of the ΔPFA indicated insufficient hip extension to compensate for the spinopelvic mismatch during upright standing.

Should central osteophytes within the articular cartilage of the lateral compartment be considered when determining the indication of unicompartmental knee arthroplasty for medial osteoarthritis?

Patients with central osteophytes in the lateral compartment may be poor candidates for unicompartmental knee arthroplasty (UKA) for medial knee arthritis given the thin overlying articular cartilage above the central osteophytes that is inadequate for supporting weight-bearing after UKA. Therefore, attempts should be made to detect central osteophytes to confirm suitability for UKA.

Differences in kinematic parameters during gait between the patients with knee osteoarthritis and healthy controls using an insole with a single inertial measurement unit: A case-control study.

BACKGROUND: An inertial measurement unit is small and lightweight, allowing patient measurements without physical constraints. This study aimed to determine the differences in kinematic parameters during gait using an insole with a single inertial measurement unit in healthy controls and on both sides in patients with knee osteoarthritis. METHODS: Twenty patients with knee osteoarthritis and 13 age-matched controls were included in this study. The participants walked at a self-selected speed and foot kinematics were measured during gait using an insole with a single inertial measurement unit. The right side of the healthy controls and both the affected and contralateral sides of patients with KOA were analyzed separately. FINDINGS: The foot extension angular velocity at toe-off was significantly reduced on the affected side than on the contralateral side (P < 0.001) and in healthy controls (P < 0.001). During the swing phase, foot posterior-anterior acceleration was significantly lower on the affected side than on the healthy controls (P = 0.005). Furthermore, despite a decrease in walking speed, foot superior-inferior acceleration at initial contact in patients was significantly lower on the contralateral side than in healthy controls (P = 0.0167), but not on the affected side (P = 0.344). INTERPRETATION: An insole with a single inertial measurement unit can detect differences in foot kinematics during gait between healthy controls and patients with knee osteoarthritis. Our findings indicate that patients with knee osteoarthritis exhibit dysfunction of push-off at toe-off and shock absorption at initial contact on the affected side.

Two-stage revision knee arthroplasty for metallosis in a patient with rheumatoid arthritis: A case report.

We report a successful case of two-stage revision total knee arthroplasty performed for treating painless metallosis after total knee arthroplasty with a metal-backed patella. A 63-year-old woman diagnosed with rheumatoid arthritis underwent left total knee arthroplasty with a metal-backed patella at 32 years of age. The patient did not have knee pain; however, knee joint swelling, a strange noise, and pigmentation were reported 4 years ago. Radiographs showed cloud and metal-line signs anteriorly and posteriorly at the femoral condyle. Therefore, a two-stage surgery was performed for infection prevention and ease of performing posterior synovectomy. The patient underwent initial synovectomy via a posterior approach, followed by anterior synovectomy and revision total knee arthroplasty. Synovectomy was performed well without perioperative infection or failure of wound healing. In cases with metallosis after total knee arthroplasty, the two-stage revision total knee arthroplasty should be considered, depending on the degree of synovial proliferation and the risk of complications.

Genome-Wide Association Study and Transcriptome of Japanese Patients with Developmental Dysplasia of the Hip Demonstrates an Association with the Ferroptosis Signaling Pathway.

This study examined the association between developmental dysplasia of the hip (DDH) and disease-associated loci in a Japanese cohort. A genome-wide association study (GWAS) of 238 Japanese patients with DDH and 2044 healthy individuals was performed. As a replicate, GWAS was also conducted on the UK Biobank data with 3315 cases and matched 74,038 controls. Gene set enrichment analyses (GSEAs) of both the genetics and transcriptome of DDH were performed. Transcriptome analysis of cartilage specimens from DDH-associated osteoarthritis and femoral neck fractures was performed as a control. Most of the lead variants were very low-frequency ones in the UK, and variants in the Japanese GWAS could not be replicated with the UK GWAS. We assigned DDH-related candidate variants to 42 and 81 genes from the Japanese and UK GWASs, respectively, using functional mapping and annotation. GSEA of gene ontology, disease ontology, and canonical pathways identified the most enriched pathway to be the ferroptosis signaling pathway, both in the Japanese gene set as well as the Japanese and UK merged set. Transcriptome GSEA also identified significant downregulation of genes in the ferroptosis signaling pathway. Thus, the ferroptosis signaling pathway may be associated with the pathogenic mechanism of DDH.

Morphological and Morphometrical Analyses of Fracture-Healing Sites of an Atypical Femoral Fracture in Patients with and without Long-Term Bisphosphonate Treatment for Osteoporosis: A Report of Two Cases.

Bisphosphonates have been the first drug of choice for osteoporosis in the recent years because of their known ability to suppress osteoclast activity. The adverse effect of long-term bisphosphonate administration in the fracture-healing process is controversial. The aim of our study was to observe not only morphology but also morphometry of the fracture site of atypical femoral fracture with and without long-term bisphosphonate administration, in a case study of two difficult-to-obtain human samples. The patients with insufficient healing of atypical femoral fracture were treated with valgus wedge osteotomy. Histomorphometrical analysis was performed in bone samples of fracture sites harvested during osteotomy. The thickness of the femoral cortex was measured in the fracture site and the adjacent, non-fracture site. A comparative analysis of the content of hypertrophic osteoclasts in fracture sites, shape and size of osteons, mass, and ratio of the woven bone to the total bone mass was performed, comparing bisphosphonate-treated and untreated samples. In bisphosphonate-treated samples, we observed femoral cortex thickening at the fracture site; the appearance of hypertrophic osteoclasts; decreased bone resorption surface, decreased osteoclast numbers on the bone resorption surface, and increased ratio of multinuclear osteoclasts; osteons were misshapen and thin; and the mass and ratio of the woven bone to the total bone mass were higher. This study demonstrated that long-term bisphosphonate administration can alter the morphological features of the fracture site compared to its physiological state.

A whole-genome transcriptome analysis of articular chondrocytes in secondary osteoarthritis of the hip.

OBJECTIVE: To date, exhaustive gene expression analyses of chondrocytes in hip osteoarthritis (OA) have yielded specific gene expression patterns. No study has reported on the exhaustive transcriptome of secondary hip OA based on acetabular dysplasia in a Japanese population, while previous reports have focused on primary or idiopathic hip OA in Caucasian populations. This study aims to search for specific gene expression patterns of secondary hip OA chondrocytes by transcriptome analysis. DESIGN: Human articular cartilage was obtained from femoral heads following hemiarthroplasty for femoral neck fracture (N = 8; non-OA) and total hip arthroplasty for secondary hip OA (N = 12). Total RNA was extracted from the articular cartilage and submitted for microarray analysis. The obtained data were used to perform gene expression analysis, GO enrichment analysis and pathway analysis and were compared with data from primary hip OA in Caucasian populations in the literature. RESULTS: We identified 888 upregulated (fold change: FC ≥ 2) and 732 downregulated (FC ≤ 0.5) genes in hip OA versus non-OA chondrocytes, respectively. Only 10% of upregulated genes were common between the secondary and primary OA. The newly found genes prominently overexpressed in the secondary hip OA chondrocytes were DPT, IGFBP7, and KLF2. Pathway analysis revealed extracellular matrix (ECM)-receptor interaction as an OA-related pathway, which was similar to previous reports in primary hip OA. CONCLUSIONS: This is the first study to report the genome-wide transcriptome of secondary hip OA chondrocytes and demonstrates new potential OA-related genes. Gene expression patterns were different between secondary and primary hip OA, although the results of pathway and functional analysis were similar.

Femoral footprint of the popliteus tendon may be at the risk of damage during total knee arthroplasty.

PURPOSE: The present study focused on the prevalence of incidental excision of the femoral footprint of the popliteus tendon during total knee arthroplasty and its associated risk factors. METHODS: A total of 275 knee arthroplasties were performed for 226 patients with varus knee osteoarthritis. The status of the femoral footprint of the popliteus tendon was intraoperatively evaluated and classified into three groups (preserved, partially excised, and completely excised), and the prevalence of the excision was identified. Femoral component size, the thickness of the resected distal femoral condyle, and preoperative patient demographic data were compared for the three groups. Ordinal logistic regression analysis was performed to reveal risk factors associated with the excision. RESULTS: The femoral footprint of the popliteus tendon was preserved in 132 knees (48.0 %), partially excised in 94 knees (34.2 %) and completely excised in 49 knees (17.8 %). The ordinal logistic regression analysis revealed thicker resection of the distal femoral condyle (p < 0.0001) and shorter body height (p = 0.0266) to be the independent risk factors for the excision. CONCLUSIONS: The incidental partial or complete excision of the femoral footprint of the popliteus tendon was identified in approximately half of the evaluated knees. Thicker resection of the distal femoral condyle and shorter body height were the most significant risk factors for the excision. LEVEL OF EVIDENCE: Case-control study, Level III.

Potential risk of excising the femoral insertion of the popliteus tendon during primary total knee arthroplasty: a biometric study.

BACKGROUND: During total knee arthroplasty (TKA), excision of the popliteus tendon leads to extensive static gaps and reduced mobility. The purpose of this study was to determine the positional relationship between the femoral insertion of the popliteus tendon and the bone cutting lines of various TKA systems. METHODS: This study included 21 cadaveric right femurs presenting no macroscopic deformity. The lateral image of the femur and the template of the femoral component were overlaid to determine the preservation/excision of the popliteus tendon insertion. TKA systems used were Genesis II, NexGen, low contact stress (LCS), PFC Σ, Scorpio, and Vanguard. The knees in which the insertion was preserved in all implants or excised in at least one implant were classified into intact or the high-risk groups, respectively. RESULTS: The popliteus tendon was preserved in all specimens with the LCS system. In contrast, the popliteus tendon insertion was excised in ≥1/3 of the specimens with the other systems. The anteroposterior diameter was significantly larger in the intact group than that in the high-risk group (58.1 ± 4.5 mm vs. 53.7 ± 2.7 mm; p = 0.018). The high-risk group included more knees from female cadavers than the intact group (70 vs. 9 %; p = 0.008). CONCLUSION: During primary TKA, the femoral insertion of the popliteus tendon could be inevitably excised, regardless of technical problems. We demonstrate that the unique design of the LCS system preserves the popliteus tendon insertion. In addition, small knees and females may be risk factors for excision of the insertion.

Effect of medial tibial torsion on the sagittal alignment of lower legs in patients with medial knee osteoarthritis.

PURPOSE: The fibular axis (FA) and anterior tibial cortex (ATC) are good determinants of the sagittal mechanical axis (MA) of lower legs during total knee arthroplasty (TKA).When compared with healthy subjects, a significant medial tibial torsion has been reported in patients with medial knee osteoarthritis; this should affect the alignment of lower legs. The purpose of this study was to clarify the effect of the medial torsion on relationship between sagittal MA and intraoperative references (FA and ATC). METHODS: Fifty knees of 50 patients with medial knee osteoarthritis who underwent primary TKA were included in this study. Using preoperative computed tomographic data, the tibial torsion angle was measured in the axial plane. The angle between FA and MA, and the angle between ATC and MA were also measured in the sagittal plane. RESULTS: The tibial torsion angle was 7.9° ± 7.2° (range -11.3° to -24.3°). The angle between MA and FA was -1.8° ± 0.8° (range -0.1° to -4.3°), and the angle between MA and ATC was 4.6° ± 0.5° (range 3.1° to 5.5°). The population variance was significantly larger for the angle between MA and FA than that between MA and ATC (P = 0.0160). There was a significant positive correlation between the tibial torsion angle and the angle between MA and FA (R (2) = 0.5111, P < 0.0001). CONCLUSION: The angle between FA and MA in the sagittal plane increased in patients with large medial tibial torsion.