Does Degree of the Pelvic Deformity Affect the Accuracy of Computed Tomography-Based Hip Navigation?

Although some navigation systems have been used for improvement of component positioning, there have been few reports regarding cases of severe pelvic deformity. We performed a retrospective review of 25 cases of total hip arthroplasty with a computed tomography-based navigation system in patients with severe pelvic deformities and estimated acetabular component position and angle between severe deformity group and mild dysplastic group as a control. There were no significant differences in accuracy of navigation system between 2 groups in terms of 3-dimensional component position or angle. Accuracy of computed tomography-based hip navigation does not depend on the degree of pelvic deformity, and this system is also useful to identify acetabular orientation and for precise component implantation in cases of pelvic deformity. © 2012 Elsevier Inc

Difficulty in locking head screw removal

Background: Locking plates are an internal fixation material useful in the treatment of bone fractures, which provides effective stabilization between the plate and locking head screws (LHSs) via the locking mechanism. However, difficulty in removing LHSs is relatively common, and such cases can require long surgical procedures or use of special removal equipment. The purpose of this study was to report the incidence and risk factors for difficult removal of LHSs. Methods: During the 5-year-6-month period from April 2006 to September 2011, 83 locking plates containing a total of 482 LHSs were removed in 80 patients at our institution. Out of 482 LHSs, there were 118 LHSs with a 2.4-2.7 mm diameter, 308 LHSs with a 3.5 mm diameter and 56 LHSs with a 5.0 mm diameter. The incidence of removal difficulty was examined on the basis of screw diameter. In addition, the risk factors were assessed in only LHSs with a 3.5 mm diameter. LHSs with a 3.5 mm diameter were divided into 2 groups, the difficult removal group and the easy removal group, and the data were examined based on age, sex, time between insertion and removal, and screw position. The incidence of removal difficulty in LHSs with a 3.5 mm diameter was examined every 6 months between insertion and removal. Results: Difficulty in removal was encountered in none (0 %) of 118 LHSs with a 2.4-2.7 mm diameter, 15 (4.9 %) of 308 LHSs with a 3.5 mm diameter, and none (0 %) of 56 LHSs with a 5.0 mm diameter. In only LHSs with a 3.5 mm diameter, the mean ages of the patients in the difficult removal group and the easy removal group were 32.1 and 45.6 years, respectively. The average time between insertion and removal in the difficult removal group and the easy removal group was 529.2 and 389.2 days, respectively. There was a statistically significant difference in age and time between insertion and removal. Removal was difficult in 15 (9.1 %) of 165 LHSs with a 3.5 mm diameter in those with >1 year between insertion and removal. Conclusion: This study suggests that (1) the use of LHSs with a 3.5 mm diameter is a necessary condition for difficulty in screw removal, and that (2) longer time from internal fixation to removal, and (3) younger age, are risk factors for it. When removing LHSs with a 3.5 mm diameter, appropriate instruments and sufficient training are necessary. © 2013 The Japanese Orthopaedic Association

Hyperostosis around the bilateral acetabulum associated with hypoparathyroidism

We report the case of a 57-year-old woman with hyperostosis around the bilateral acetabulum associated with untreated secondary hypoparathyroidism. She presented with gait disturbance and inability to walk. Radiographs showed abnormal ossification around her hips. We resected the ossifications to improve joint function. One year after surgery, radiographs showed no recurrence of ossification. When radiographs show excessive hyperostosis, it is important to exclude presence of metabolic bone disease. © Japan College of Rheumatology 2012.This is the pre-peer reviewed version of the following article: [Full cite], which has been published in final form at [link to final article]

Innovative antimicrobial coating of titanium implants with iodine

Background: Postoperative infection associated with implants remains a serious complication in orthopedic surgery. Several biomaterial surface treatments have been proposed as a means of reducing the incidence of implantassociated infections. In this study, a clinical trial was performed using an iodine-supported titanium that suppresses the microbial activities. Methods: A total of 222 patients with postoperative infection or compromised status were treated using iodinesupported titanium implants. The mean age of the patients was 49.4 years (range 5-85 years). One hundred twentyseven patients were male and 95 were female. In 158 patients, iodine-supported implants were used to prevent infection, such as compromised hosts and conditions, and in 64 patients to treat active infection. White blood cell (WBCs) and C-reactive protein (CRP) levels were measured pre- and postoperatively in all patients. To confirm whether iodine from the implant affected physiological functions, thyroid hormone levels in the blood were examined. Both examinations were conducted sequentially for a year. Radiological evaluations were performed regularly after the operation. The chronological changes of the iodine amount were evaluated using half pins removed after completion of external fixation. Results: The mean follow-up period was 18.4 months (range 3-44 months). Acute infection developed in three tumor cases among the 158 patients on preventive therapy. All three recovered without removal of the implants. Infection was cured in all 64 patients with infection. Median WBC levels were in the normal range, and median CRP levels returned to <0.5 within 4 weeks after surgery. Abnormalities of thyroid gland function were not detected. None of the patients experienced loosening of the implants. There were two patients with mechanical implant failure, which was treated by re-implantation. Excellent bone ingrowth and ongrowth were found around all hip and tumor prostheses. One year later, the amount of iodine on external fixation pins remained about 20-30 %. Conclusions: Iodine-supported titanium implants can be very effective for preventing and treating infections after orthopedic surgery. Cytotoxicity and adverse effects were not detected

Quantitative analysis of the Trendelenburg test and invention of a modified method

Background While the Trendelenburg test has been used for 120 years to detect hip abductor muscle weakness, the methodology has not been standardised. Purposes This study undertook to quantitatively analyze the relation between abductor muscle activity and pelvic tilt angle in the Trendelenburg one-leg stance, examine the pitfalls associated with performing the T-test, and develop a modified method that will produce reliable results. Methods A convenience sample of 15 healthy males was asked to assume a one-leg stance in ten different postures, five with mild flexion on the unsupported side, and five with severe flexion. Trunk sway angle, pelvic tilt angle, and the pelvic on femur (POF) angle were measured for each posture. Statistical analysis was used to assess differences in hip abductor activity and public tilt angle between the control posture and the test postures. Results With minimum trunk sway, hip abductor muscle activity increases when the pelvis is elevated and decreases when it is dropped. With trunk sway toward the test side, abductor muscle activity decreased when the pelvis was elevated; with trunk sway toward the non-test side, muscle activity stayed approximately constant when the pelvis was dropped. Conclusions Based on the results we developed a modified T-test methodology that would improve reliability. This test should be performed with minimum trunk sway and severe flexion on the non-test side. The assessment of muscle weakness is based on whether the patient can keep the single-leg standing posture when forced to elevate the pelvis, not simply on the pelvic drop. In future research, we will perform the modified T-test on patients with a suspected hip abductor deficiency, and assess the usefulness of the modified test. © 2016 The Japanese Orthopaedic Associatio