Yoshiteru Kawasaki

Lumbar spinal disorders in patients with athetoid cerebral palsy: a clinical and biomechanical study.

Study Design. Radiologic study for patients with athetoid cerebral palsy (CP), and a biomechanical study using the finite-element model (FEM). Objectives. To understand the lumbar disorders of athetoid CP patients and the etiology based on the results from the FEM study. Summary of Background Data. Cervical spondylotic myelopathy is a well-identified spinal disorder associated with cerebral palsy, especially in athetoid type. One can rationalize that the athetoid involuntary trunk movement may induce stress-related lumbar disorders. Until now, very few investigations have been conducted on lumbar disorders that could occur in patients with CP. Methods. Sixty-one cases with athetoid cerebral palsy were clinically reviewed. Radiographs of the lumbar spine in 30 cases with low back pain were taken. From these radiographs, the incidence of lumbar spondylolysis and endplate lesion was analyzed. The biomechanical study was conducted using a three-dimensional FEM of the ligamentous lumbar spine. Axial compression of 400 N was applied to simulate preload on the spine during the standing position followed with 10.6 Nm moment to simulate extension and axial rotation. The combined motion of extension and axial rotation was also simulated. During supine position, pure extension and rotation were simulated, and no preload was applied. The von Mises stresses were computed at the pars interarticularis at the each level and compared for different motions. Results. Among the 61 patients, 41 complained of symptoms such as low back and leg pain. Thirty of these 41 patients gave their consents to undergo radiographic evaluation. Twenty-eight of the 30 patients (93.3%) showed stress-related disorders such as the spondylolysis and/or vertebral endplate lesions. Spondylolysis was found in 18 of the 30 patients (60.0%). Spondylolysis was observed at the multiple levels in 4 patients involving two levels in 2 cases and three levels in the other 2 cases. Vertebral endplate lesions (deformity) were seen in 26 (86.7%) of the 30 patients. Overall, the lesions (deformity) were found in 109 of 330 endplates (33.0%) out of all lumbar endplates in the 30 patients. The FEM based results showed that stresses at pars interarticularis of L5 were the highest of all levels in all loading modes, with or without preload. However, compared with the extension or axial rotation alone modes, the combined motion of extension and rotation showed higher stresses at the pars interarticularis. Conclusions. The athetoid involuntary movements in CP patients may cause stress-related lumbar disorders. Especially, combined extension and rotation due to the involuntary trunk motion may contribute to the high incidence of spondylolysis.

Location of intrapelvic vessels around the acetabulum assessed by three-dimensional computed tomographic angiography: prevention of vascular-related complications in total hip arthroplasty

BackgroundDuring total hip arthroplasty (THA), the external iliac, femoral, and obturator vessels are at risk of vascular injury when penetrating the inner cortex of the pelvis. The purpose of this study was to clarify the location of these vessels using three-dimensional computed tomographic angiography (3DCT-A).MethodsWe enrolled 100 subjects (200 hips) without hip disease and performed examinations on the following. (1) External iliac–femoral vessels: we measured the shortest distance from these vessels to the pelvis on axial CT images and investigated the factors affecting distance. The anatomical course of the iliac artery was classified as straight, curved, or tortuous, and the correlation between course and age was established. (2) Obturator vessels: we measured the shortest distance from the obturator vessels to the quadrilateral surface on axial CT images. (3) Visualization of pelvic vessels was through the pelvis by dual-phase 3DCT-A.Results(1) The external iliac vein was located significantly closer to the pelvis than the artery, especially on the left side and in aged and female subjects. The single-curved and tortuous double-curved vessel types were found in aged subjects, and external iliac vessels of these types were closer to the pelvis than vessels of the straight type. In 36 subjects, the external iliac veins lay directly on the osseous surface of the pelvis (right 16, left 36). Of these 36 subjects, only one had straight-type vessels. (2) Obturator vessels were located just behind the acetabulum near the obturator foramen. (3) Reconstructed 3DCT images enabled us to visualize the pelvic vessels and demonstrated the danger area for penetrating the inner cortex of the pelvis.ConclusionUnderstanding the anatomical orientation of the pelvic vessels around the acetabulum using 3DCT-A could be helpful for preventing vascular injury during THA.

Subchondral cysts in dysplastic osteoarthritic hips communicate with the joint space: analysis using three-dimensional computed tomography

IntroductionBone cyst formation in hips increases as osteoarthritis worsens. Although bone cysts in hips have been described in many studies, their etiology remains unclear and under debate. The purpose of this study was to investigate the communication between a bone cyst and the joint space, as well as the relationship between the severity of osteoarthritis and the formation of subchondral bone cysts in dysplastic hips.MethodWe studied bone cysts from 150 dysplastic hips in 97 patients by computed tomography (CT) and plain radiography. We investigated the distribution of the bone cysts and the presence or absence of a communication path between the cysts and the joint space by three-dimensional (3D) CT.ResultOf the 150 hips, 94 acetabula and 55 femoral heads were found to contain cysts. Of the 94 hips containing acetabular cysts, 89 and 5 hips showed black lines and gray lines connecting the cyst and the joint space, respectively, on 3D-CT. The rate of cyst presentation in the hip increased as the joint space became narrower. The number of hips that possessed cysts in the anterior and/or middle portion was significantly higher than that in the posterior portions.ConclusionBone cysts in dysplastic osteoarthritic hips were found to communicate with the joint space in all cases. This suggests that the formation and enlargement of the cysts in dysplastic hips may be greatly influenced by the joint fluid. Cyst formation was initially observed in the anterior acetabulum, gradually progressing to involve the entire joint, including the posterior acetabulum and the femoral head, with worsening of the osteoarthritis.

Fragmental bone transport in conjunction with acute shortening followed by gradual lengthening for a failed infected nonunion of the tibia

Ilizarov reconstructions have been regarded as potent techniques to treat infected nonunion with a large bone defect. These techniques generally include bone transport and acute shortening if it is applicable followed by gradual lengthening as well as simple bone lengthening. Fragmental bone transport has been also applied to a hemicircumferential bone defect, which is often described by cavitary osteomyelitis or hemicortical sequestrate. In these conditions, bony continuity is maintained in some part despite a bone defect on the other side that chronically drains. This technique allows sparing bone stock while preventing sacrifi ce of bony continuity from unnecessary debridement. In the following case report, we present fragmental bone transport in conjunction with acute shortening followed by gradual lengthening for treatment of an infected nonunion of the tibia. The treatment was performed according to the strategy in which living bone is effi ciently utilized so long as vascularity is confi rmed. As a result, the defect of the tibia had anterior longer and posterior shorter lengths at the single bone segment. To our knowledge, this is the fi rst report of a successful unique technique for a failed infected nonunion of the tibia with a huge bone defect that had circumferentially nonuniform defect length.

Diagnostic Value of the Supine Napoleon Test for Subscapularis Tendon Lesions.

PURPOSE The purpose of this study was to compare the diagnostic value of the supine Napoleon test (a variation of the belly-press test that reduces compensatory motion) with other clinical tests for subscapularis tendon (SSC) tears. METHODS One hundred thirty consecutive patients who were scheduled for arthroscopic rotator cuff repair were evaluated preoperatively with the lift-off test, Napoleon test, bear-hug test, and supine Napoleon test. The supine Napoleon test was performed by placing the patients hand on their belly while they lay supine with an examiner holding their hand and shoulder to prevent compensatory motion. The patient was asked to move their elbow upward and the test was considered positive if they were unable to do so. During surgery, SSC lesions were classified with the Lafosse classification system. Sensitivity, specificity, accuracy, and positive and negative likelihood ratios (LR+, LR-) were calculated for each test. The ability to detect partial SSC tears was compared among the clinical tests. RESULTS Fifty-two of 130 patients (40%) had SSC tears confirmed arthroscopically. For diagnosis of these tears, the supine Napoleon test was the most sensitive (84%), followed by the bear-hug test (74%), and the bear-hug test was the most specific (97%), followed by the supine Napoleon test (96%). The LR+ was greatest for the bear-hug test (28.4) and next greatest for the supine Napoleon test (21.9). The LR- was lowest for the supine Napoleon test (0.16) and the bear-hug test was second (0.27). The sensitivity of the supine Napoleon test (65%) was highest for detecting partial tears. CONCLUSIONS In comparison with other clinical tests for SSC tears, the supine Napoleon test had the greatest diagnostic value for full-thickness SSC tears and was most able to detect partial tears. LEVEL OF EVIDENCE Level III, diagnostic nonrandomized study.

Navigation-Assisted Total Knee Arthroplasty for Osteoarthritis with Extra-Articular Femoral Deformity and/or Retained Hardware

Total knee arthroplasty (TKA) for osteoarthritis (OA) patients with extra-articular deformity is still challenging because angular deformity, canal sclerosis, or the retained hardware that precludes the use of the traditional intramedullary guide. In addition, atypical bone cut for intra-articular correction leads to imbalanced soft tissue gap. Furthermore, corrective osteotomy should be considered for severe deformity or para-articular deformity cases. Recently, navigation-assisted TKA has been reported to increase the accuracy of prosthetic positioning and limb alignment. This system can calculate mechanical axis regardless of extra-articular deformity, canal sclerosis, or retained hardware. Accordingly, navigation surgery has been considered to be a powerful option especially in TKAs with extra-articular deformity cases. Here, we report 3 successful navigation-assisted TKAs for osteoarthritis with extra-articular deformities and/or retained hardware. Navigation-assisted TKA is an effective and reliable alternative for patients with extra-articular deformities.

Arthroscopic Removal of a Wire Fragment from the Posterior Septum of the Knee following Tension Band Wiring of a Patellar Fracture

Tension band wiring with cerclage wiring is most widely used for treating displaced patellar fractures. Although wire breakage is not uncommon, migration of a fragment of the broken wire is rare, especially migration into the knee joint. We describe here a rare case of migration of a wire fragment into the posterior septum of the knee joint after fixation of a displaced patellar fracture with tension band wiring and cerclage wiring. Although it was difficult to determine whether the wire fragment was located within or outside the knee joint from the preoperative plain radiographs or three-dimensional computed tomography (3D CT), we found it arthroscopically through the posterior transseptal portal with assistance of intraoperative fluoroscopy. Surgeons who treat such cases should bear in mind the possibility that wire could be embedded in the posterior septum of the knee joint.