Publications by authors named "Keizo Wada"

Background: Both scapular dynamics and static scapular position are important in the treatment of shoulder dysfunction. This study aimed to create an index that can evaluate scapular position on plain radiographs and evaluate the relation between scapular position and posture accurately.

Methods: Using four fresh frozen cadavers, we developed a glenoid angle grade based on the degree of overlap between the shadow of the coracoid inflection point and the upper edge of the scapula on frontal plain radiographs: grade 1, no overlap; grade 2, overlaps by less than half of the shadow; grade 3, overlaps by more than half.

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Introduction: Trabecular bone score (TBS) is partially independent of fracture risk. Reference values for TBS have not been established in official guidelines, and thus clinicians often have difficulty interpreting TBS results. This study aimed to investigate whether reference values for TBS could be a valid indicator for clinical vertebral fracture (CVF).

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The purpose of this study was to directly compare implant placement accuracy and postoperative limb alignment between robotic-assisted total knee arthroplasty and navigation-assisted total knee arthroplasty. This retrospective case-control study included a consecutive series of 182 knees (robotic-assisted group, n = 103 knees; navigation-assisted group, n = 79). An image-free handheld robotic system (NAVIO) or an image-free navigation system (Precision N) was used.

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Full-endoscopic (FE) lumbar interbody fusion (LIF) is now a widely used type of minimally invasive surgery (MIS). Although FE-LIF includes LIF with foraminoplasty via a Kambin's triangle approach (FE-KLIF) and LIF with foraminotomy via an interlaminar approach, these techniques are rarely discussed separately. This review evaluates the outcomes and complications of FE-KLIF reported in the literature.

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has the ability to form biofilm; therefore, the treatment of prosthetic joint infection involving is often challenging. This report describes the first case of acute hematogenous prosthetic knee joint infection with that occurred as a result of an asymptomatic gallbladder abscess. The patient was a 78-year-old man who underwent bilateral total knee arthroplasty 6 years ago.

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Background: Although bicruciate stabilized total knee arthroplasty (BCS-TKA) is expected to provide kinematics similar to those of the normal knee, there are limited data available for comparison of the kinematics of the knee after BCS-TKA with those of the normal knee. The purpose of this study was to confirm whether the knee after BCS-TKA are the same as those of the native knee.

Methods: Seven fresh-frozen cadavers underwent TKA using a BCS-type prosthesis with navigation system.

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Purpose: Patient-perceived leg length discrepancy (PLLD) is one of the major postoperative complications of total hip arthroplasty (THA). This study aimed to identify factors that cause PLLD following THA.

Materials And Methods: This retrospective study included a series of consecutive patients who underwent unilateral THA between 2015 and 2020.

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Background: Soft tissue balance is an important determinant of the outcome of total knee arthroplasty (TKA). However, there are differences in the joint gap and ligament balance between the osteotomized femoral and tibial surfaces and those after TKA. The aim of this study was to compare the relationship between the femur and tibia at insertion of a spacer block with that after cruciate-retaining (CR) TKA.

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Iliopsoas impingement after total hip arthroplasty is caused by the implant irritating the iliopsoas muscle, but changes in the iliopsoas muscle have not been quantitatively evaluated. This study assessed changes in the surface pressure of the iliopsoas muscle when the implant alignment was varied. Total hip arthroplasty was performed in 10 fresh-frozen cadaveric hips.

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Background: This study evaluated the accuracy of the cup alignment angles and spatial cup positioning on computed tomography (CT) images in patients with osteoarthritis secondary to developmental dysplasia of the hip (DDH) who underwent total hip arthroplasty (THA) using a minimally invasive technique via an anterolateral approach in the supine position according to whether a robotic arm-assisted system or a CT-based navigation system was used.

Methods: We reviewed 60 robotic arm-assisted (RA)-THA cases and 174 navigation-assisted (NA)-THA cases. After propensity score matching, there were 52 hips in each group.

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Background: The trabecular bone score (TBS) is reported to be an independent predictor of fracture risk in patients with primary or secondary osteoporosis. However, there have been few reports on its use in the Japanese population. This study aimed to investigate the risk factors for vertebral fracture in the Japanese population and to evaluate the usefulness of TBS.

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Article Synopsis
  • This study evaluates how the position of the baseplate in reverse shoulder arthroplasty (RSA) impacts the placement and length of superior screws, aiming to reduce the risk of suprascapular nerve injury.
  • Researchers used 3D computer simulations based on CT scans of cadaver shoulders to analyze various baseplate positions and their effects on screw measurements.
  • Results suggested that using a 1-7 o'clock rotation with a 0-degree inferior tilt for the baseplate helps increase the distance from the superior screw to the suprascapular notch, minimizing nerve injury risks despite a shorter inferior screw length.
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Article Synopsis
  • Iliopsoas impingement (IPI) is a complication following total hip arthroplasty (THA), with this study aiming to identify risk factors and a critical measurement for symptomatic IPI.
  • A review of 218 hips from 190 patients showed a symptomatic IPI incidence of 11.0%, predominantly in hips affected by osteonecrosis, with notable differences in pre- and postoperative hip flexion angles and cup protrusion length.
  • The study determined a threshold cup protrusion length of 3.9 mm as significant for predicting IPI, suggesting it could help in identifying patients who may benefit from conservative treatment options.
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Article Synopsis
  • * Resection of the medial arm of the iliofemoral ligament significantly increased external rotation, while the conjoined tendon was found to be the primary restraint against internal rotation.
  • * Removing multiple stabilizing structures can greatly compromise hip joint stability under axial traction, highlighting the importance of maintaining the iliofemoral ligament and conjoined tendon during THA.
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Purpose: To investigate the association of spinal anomalies with lumbar spondylolysis and spina bifida occulta (SBO).

Methods: A total of 1190 patients with thoracic, abdominal, and pelvic computed tomography scans available were categorized according to the number of presacral (thoracic and lumbar) mobile vertebrae and the presence or absence of lumbosacral transitional vertebrae (LSTV). The prevalence of spondylolysis and SBO and the association of spinal anomalies with these disorders were evaluated.

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The purpose of this study was to determine the optimal position of the baseplate on the small glenoid of female Japanese. Two sets of 3D scapular models were made according to the CT data of 7 female cadavers. We set two scenarios of the baseplate placement : A and B.

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Background: Soft tissue balancing in bicruciate-retaining (BCR) total knee arthroplasty (TKA) is a challenge that must be overcome to achieve excellent clinical outcomes. However, the optimal degree of joint laxity has yet to be clarified. This cadaveric study sought to examine joint laxity after BCR TKA using a navigation system.

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Background: A highly porous titanium cup has a unique structure that mimics human trabecular bone and is expected to achieve better outcomes due to rigid fixation and extensive bone ingrowth. Several manufacturers have developed a highly porous titanium cup; however, some have shown a high incidence of radiolucent lines (RLLs) on early postoperative radiographs. In this study, we compared the clinical and radiological outcomes of total hip arthroplasty (THA) using a highly porous titanium cup (OsseoTi, Zimmer Biomet) with those after THA using a conventional hydroxyapatite-coated titanium cup (Trident HA, Stryker).

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Background: An understanding of the insertional footprints of the capsular ligaments of the hip is important for preserving hip function and stability given the increasing number of minimally invasive hip surgeries being performed under a limited surgical view. However, it is difficult to detect these ligaments intraoperatively and many surgeons may not fully appreciate their complex anatomy. The aims of this study were to quantify the proximal and distal footprints of the iliofemoral ligament (ILFL) and ischiofemoral ligament (ISFL) and to estimate the location of the corresponding osseous landmarks on the proximal femur, which can be detected easily during surgery.

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Introduction: Intertrochanteric fractures are common fragility fractures in elderly patients. The importance of a reliable classification system for these fractures has been increasingly recognized. The aim of this study was to test the hypothesis that three-dimensional classification by CT has better intra- and inter-observer reliability than conventional two-dimensional classification.

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Introduction: Unicompartmental knee arthroplasty (UKA) is a well-accepted treatment for isolated unicompartmental osteoarthritis (OA) of the knee. In previous literature, it has been suggested that bi-unicompartmental knee arthroplasty (bi-UKA) which uses two UKA implants in both the medial and lateral compartments of the same knee is a feasible and viable option for the treatment of knee OA. Given the advantages of UKA treatment, it is warranted to review the literature of bi-UKA and discuss the evidence in terms of implant selection, indications, surgical techniques, and outcomes, respectively.

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The Rotational osteotomy for femoral retroversion has been extremely rare despite the known association between femoral neck retroversion, hip pain, and osteoarthritis. Here, we describe a case of femoral neck retroversion for which proximal femoral rotation osteotomy. A 16-year-old boy with a past history of developmental dysplasia of the both hip treated conservatively presented with a complaint of pain in left hips.

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The aim of this cadaveric study was to evaluate the intraoperative kinematics of the native knee including two-dimensional translation of the femur using a navigation system. Eight native knees of 4 fresh-frozen whole-body cadavers were used for the study. The kinematics of each knee were analyzed intraoperatively using the navigation system.

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A novel three-dimensional fragment-based classification system based on computed tomography findings was established to characterize femoral intertrochanteric fractures. The intertrochanteric bone fragments were defined as follows : neck, posterior portion of the greater trochanter, anterior portion of the greater trochanter, lesser trochanter, and shaft. Each type of fracture was classified as 2-, 3-, 4-, or 5-fragment according to the number of floating bone fragments.

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Background: Achieving favourable outcomes in high-hip centre reconstruction in hip dysplasia requires the optimal cup height and size, which can provide sufficient bone coverage for stable cup fixation that fits the anteroposterior acetabular rim without increasing the cup height more than necessary.

Methods: We retrospectively reviewed 214 patients who underwent primary total hip arthroplasty (THA) and identified 30 hips with Crowe II ( = 15) or III ( = 15) developmental dysplasia of the hip (DDH). We measured the cup-centre-edge angle (cup-CE) and the vertical and horizontal distances from the teardrop.

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