Yusuke Okanoue

Determining the rotational alignment of the tibial component at total knee replacement: A COMPARISON OF TWO TECHNIQUES

We prospectively assessed the benefits of using either a range-of-movement technique or an anatomical landmark method to determine the rotational alignment of the tibial component during total knee replacement. We analysed the cut proximal tibia intraoperatively, determining anteroposterior axes by the range-of-movement technique and comparing them with the anatomical anteroposterior axis. We found that the range-of-movement technique tended to leave the tibial component more internally rotated than when anatomical landmarks were used. In addition, it gave widely variable results (mean 7.5 degrees ; 2 degrees to 17 degrees ), determined to some extent by which posterior reference point was used. Because of the wide variability and the possibilities for error, we consider that it is inappropriate to use the range-of-movement technique as the sole method of determining alignment of the tibial component during total knee replacement.

Safe zone for the superior gluteal nerve in the transgluteal approach to the dysplastic hip: Intraoperative evaluation using a nerve stimulator

Background The superior gluteal nerve can be damaged during the transgluteal approach to the hip in total hip arthroplasty. Methods We studied 30 patients with hip dysplasia who underwent total hip arthroplasty through the transgluteal approach. The course of the inferior branch of the superior gluteal nerve was identified using a nerve stimulator. The distance between the nerve and the tip of the greater trochanter was measured. Results The mean distance was 37 (25–45) mm at the anterior third, 40 (30–50) mm at the middle third, and 44 (35–55) mm at the posterior third of the gluteus medius. The distance was influenced by the severity of hip dysplasia and decreased as the degree of hip dysplasia became more severe. Interpretation A 3-cm safe zone is appropriate in most dysplastic hips. In severely dysplastic hips, however, the superior gluteal nerve occasionally coursed within 3 cm of the tip of the greater trochanter. In such hips, a nerve stimulator can be used to identify the nerve.

Total hip arthroplasty with a sliding iliac graft for acetabular dysplasia

We describe a new technique of reconstruction of the deficient acetabulum in cementless total hip arthroplasty. The outer iliac table just above the deficient acetabulum is osteotomised and slid downwards. We have termed this an iliac sliding graft. Between October 1997 and November 2001, cementless total hip arthroplasty with an iliac sliding graft was performed on 19 patients (19 hips) with acetabular dysplasia. The mean follow-up was 3.4 years (2 to 6). The mean pre-operative Harris hip score was 45.1 which improved significantly to 85.3 at the time of the final follow-up. No patient had post-operative abductor dysfunction. Incorporation of the graft was seen after two to three months in all patients. Resorption of the graft and radiolucencies were infrequent. This technique is a useful alternative to femoral head autografting when the patients own femoral head cannot be used.

Nociceptive phenotype alterations of dorsal root ganglia neurons innervating the subchondral bone in osteoarthritic rat knee joints

OBJECTIVE Subchondral bone plays a role in generating knee joint pain in osteoarthritis (OA). The objective of this study was to clarify nociceptive phenotype alterations of subchondral bone afferents of the distal femur in mono-iodoacetate (MIA)-induced OA rats. METHODS OA was induced by intra-articular injection of MIA in rats. Two different retrograde tracers were separately injected into the knee joint cavity and the subchondral bone to identify joint and subchondral bone afferents. Immunohistochemistry was used at 2 weeks (early stage) and 6 weeks (advanced stage) after MIA injection to determine the expression of nociceptive markers (calcitonin gene-related peptide (CGRP) and tyrosine receptor kinase A (TrkA)) and the soma size distribution of CGRP-immunoreactive (IR) neurons. Histological subchondral bone and cartilage damage was scored according to the Osteoarthritis Research Society International grading system. Pain-related behavior was evaluated using weight distribution and mechanical sensitivity of the hind paw. RESULTS OA caused an up-regulation of CGRP, TrkA and enlargement of soma size of CGRP-IR neurons in both joint and subchondral bone afferents. CGRP and TrkA expression in subchondral bone afferents gradually increased over 6 weeks. Furthermore, up-regulation of CGRP and TrkA in subchondral bone afferents displayed a strong correlation with the subchondral bone damage score. CONCLUSION Up-regulation of nociceptive markers in subchondral bone afferents correlated with subchondral bone damage, suggesting that subchondral bone is a therapeutic target, especially in the case of advanced stage knee OA. In particular, CGRP and TrkA are potentially molecular therapeutic targets to treat joint pain associated with subchondral lesions.

Askin tumor with metastasis to the scalp: a histochemical, immunohistochemical and ultrastructural study

A 29-year-old woman presented with facial edema, and imaging disclosed a tumor extending from the anterior chest wall to the anterosuperior aspect of the mediastinum. Transbronchial cytology of the primary tumor and biopsy of the metastatic scalp lesion were performed. Histologically, the tumor consisted of closely packed small round cells. The neoplastic cells generally had round nuclei, finely dispersed chromatin, and small to prominent nucleoli. Histochemically, the cytoplasm of the neoplastic cells contained abundant glycogen and stained with Grimelius silver. Immunohistochemically, the neoplastic cell membranes reacted with CD99 (MIC2) and the neoplastic nuclei reacted with Fli-1, but various other markers, including lymphocyte and skeletal muscle markers, were not detected. No neoplastic cells were also reactive for chromogranin A, synaptophysin, and neurofilament. Ultrastructurally, some neoplastic cells had delicate cytoplasmic processes and contained membrane-bound dense core granules in the cytoplasm. Even if results are immunohistochemically negative for neuroendocrine markers, the combination of immunohistochemistry of CD99 (MIC2) and Fil-1 may be useful in diagnosing Askin tumor or its metastatic lesion.

An Intramedullary Free Vascularized Fibular Graft Combined with Pasteurized Autologous Bone Graft in Leg Reconstruction for Patients with Osteosarcoma

The use of pasteurized autologous bone graft has been an innovation in limb-salvage surgery; however, its principal disadvantage is fracture, infection, pseudoarthrosis, and bone resorption. We present two cases in which an intramedullary free vascularized fibular graft combined with pasteurized autologous bone graft was performed for immediate femur or tibia reconstruction following osteosarcoma resection. The rationale of this method is to combine the mechanical strength of a pasteurized bone with the biological activity of a vascularized bone. The pasteurized bone graft provides bone stock and early stability and the addition of the vascularized bone graft substantially facilitates host-pasteurized bone union. This combination procedure may be a recommended option for reconstruction of the lower leg, preserving knee joint function for patients with osteosarcoma.

Diagnostic value of triple-phase bone scintigraphy for the diagnosis of infection around antibiotic-impregnated cement spacers

IntroductionTwo-stage revision arthroplasty is today considered as the gold standard for control of chronic deep prosthetic infection. Although the revision arthroplasty should only be considered when infection is eliminated, the diagnosis of residual infection prior to the revision remains a challenging problem.Materials and methodsWe evaluated triple-phase bone scintigraphy as a useful diagnostic test for the detection of residual infection around the antibiotic-impregnated cement spacer in patients waiting for the second-stage revision hip or knee arthroplasty. Increased uptake of radioisotope in all three phases was considered positive for infection. The final diagnosis was based on histopathological results in addition to microbiologic examinations of surgical specimens.ResultsHistopathological examination showed positive in 17 and negative in 13 out of 30 examinations. Among 17 samples positive for histopathology, there were only 4 samples positive for bacterial culture. All samples negative for histopathology showed negative for bacterial culture. The positive and negative predictive values of triple-phase bone scintigraphy for the presence of infection were 80% and 90%, respectively. The diagnostic sensitivity was 94% and the specificity was 69%.ConclusionTriple-phase bone scintigraphy was useful in the diagnosis of infection around the articulating cement spacer. In particular, when triple-phase bone scintigraphy shows negative, the residual infection around the cement spacer is unlikely.

Chronological changes in functional cup position at 10 years after total hip arthroplasty

Purpose This study aims to clarify the chronological changes in functional cup position at a minimum follow-up of 10 years after total hip arthroplasty (THA), and to identify the risk factors influencing a significant difference in functional cup position during the postoperative follow-up period. Methods We evaluated the chronological changes in functional cup position at a minimum follow-up of 10 years after THA in 58 patients with unilateral hip osteoarthritis. Radiographic cup position was measured on anteroposterior pelvic radiographs with the patient in the supine position, whereas functional cup position was recorded in the standing position. Radiographs were obtained before, 3 weeks after, and every 1 year after surgery. Results Functional cup anteversion (F-Ant) increased over time, and was found to have significantly increased at final follow-up compared to that at 3 weeks after surgery (p<0.01). The maximum postoperative change in F-Ant was 17.0° anteriorly; 12 cases (21%) showed a postoperative change in F-Ant by >10° anteriorly. Preoperative posterior pelvic tilt in the standing position and vertebral fractures after THA were significant predictors of increasing functional cup anteversion. Conclusions Although chronological changes in functional cup position do occur after THA, their magnitude is relatively low. However, posterior impingement is likely to occur, which may cause edge loading, wear of the polyethylene liner, and anterior dislocation of the hip. We believe that, for the combined anteversion technique, the safe zone should probably be 5°-10° narrower in patients predicted to show considerable changes in functional cup position compared with standard cases.

A pilot feasibility study for immediate relief of referred knee pain by hip traction in hip osteoarthritis

Abstract It is generally accepted that osteoarthritis of the hip is a common cause of pain and disability. In clinical practice, a variety of conservative and surgical methods are available for patients with hip osteoarthritis. Nonsurgical interventions are recommended as the first-line treatment for hip osteoarthritis [1]. As one of the conservative therapies used in nonsurgical interventions, physical therapy, including hip traction and stretching, has been shown to reduce pain and improve hip function in patients with hip osteoarthritis [2]. Pain originating from the hip joint is distributed not only in the groin area but also in the buttocks, anterior thighs, and knees [3, 4]. Knee pain arising from the hip joint is one of the characteristics of referred pain in hip osteoarthritis. However, the effects of physical therapy on referred pain have not been well documented. We developed an original hip traction technique using a lumbar traction machine. Of note, patients treated with this method experienced immediate relief of referred knee pain. This study describes the results of immediate relief of referred knee pain because using hip traction.

Less Invasive Shelf Acetabuloplasty for Patients with Dysplasia of the Hip

The shelf acetabuloplasty for developmental dysplasia of the hip (DDH) is a simpler technique compared with periarticular acetabular osteotomies. However, the most commonly used approach involves the exposure of a large section of the outer iliac surface via a long skin incision and is relatively invasive. We have developed a mini one-incision technique for shelf acetabuloplasty using bioabsorbable material, based on a modified Spitzy method. The advantages of this procedure are the small, single skin incision and minimal removal of the gluteus medius from the outer iliac surface. Based on our results, we believe that this procedure could be considered to be effective for the treatment of DDH.