A forty millimetre head significantly improves range of motion compared with a twenty eight millimetre head in total hip arthroplasty using a computed tomography-based navigation system.

PURPOSE: Larger-diameter (≥40 mm) femoral heads decrease the incidence of post-operative dislocation in total hip arthroplasty (THA). This study was conducted to discover whether larger-diameter femoral heads result in greater range of motion of the hip with the use of a computed tomography (CT)-based navigation system. METHODS: Thirty-nine primary THAs were performed via a posterolateral approach using a CT-based navigation system. The stem was inserted in the femur in line with the original femoral neck anteversion. Considering the range of motion during various daily activities which could occur without impingement, the cup anteversion was decided at 10 ° increments according to the stem anteversion. While the cup inclination was set at 40 ° in order to avoid a high inclination angle to prevent the edge roading between the HXLPE liner and ceramic head. After implantation, trial liners and femoral heads were used with either 28 or 40 mm diameter. Maximal hip flexion, extension, abduction, external rotation in extension at 0° and internal rotation angles in flexion at 90 ° were measured. The differences between the ranges of motion with the 40-mm and 28-mm heads were tested. The results were assessed with paired Student t-tests. RESULTS: The ranges of motion in flexion, extension, abduction and internal rotation angles improved significantly with the 40-mm heads compared with the 28-mm heads. The ranges of motion of cases where maximal flexion angle was 90° or less were excluded, improved significantly with the 40 mm heads. CONCLUSIONS: We concluded that the larger-diameter 40-mm femoral prosthetic heads result in greater ranges of motion in flexion, extension, abduction and internal rotation.

[Multidisciplinary strategy for lung cancer patients with bone metastasis].

The fall of QOL by bone metastasis poses a problem with the increase in lung cancer. The examples of long-term survival of lung cancer are also increasing by progress of chemotherapy or molecular-targeted therapy. Now, in addition to the conventional radiotherapy, the multidisciplinary treatment including a newer bisphosphonates or an orthopedic operation has been needed to bone metastasis of lung cancer. We presented the lung cancer case who showed the symptoms in transcervical pathologic fracture and whose QOL was improved by orthopedic surgery, radiotherapy to bone metastasis, chemotherapy, gamma knife surgery, and treatment with zoledronic acid and gefitinib.

Cervical extradural en-plaque meningioma.

A 22-year-old woman presented with a very rare extradural en-plaque spinal meningioma manifesting as right hemiparesis and gait disturbance. Magnetic resonance imaging revealed a well-enhanced lesion extending from the C-1 to C-5 vertebral levels, compressing the cord dorsally. Computed tomography revealed a slightly enhanced mass with calcification in the spinal canal, advancing in all directions except anteriorly. Surgery could not completely remove the part of the tumor that had progressed laterally. The histological diagnosis was cervical extradural en-plaque meningioma. Postoperatively, there was remarkable improvement in the patient's symptoms. Successful treatment of this type of tumor requires the development of a combined surgical and radiosurgical approach.

Sagittal alignment of the subaxial cervical spine after C1-C2 transarticular screw fixation in rheumatoid arthritis.

Several articles reported the association between the development of subaxial kyphosis and the hyperlordotic fixation of C1-C2. However, their patients were heterogeneous in both primary disease and operative procedure. Transarticular screw fixation has become a popular procedure for C1-C2 arthrodesis instead of wiring techniques in which C1-C2 is difficult to fix in the intended alignment. Furthermore, in rheumatoid arthritis (RA) patients, subaxial lesions play an important role in potential subaxial alignment changes. The subaxial influences after C1-C2 transarticular screw fixation in patients with RA are unclear. To investigate the radiographic features of the subaxial cervical spine after C1-C2 transarticular screw fixation for RA, we reviewed 28 cases of C1-C2 transarticular screw fixation for rheumatoid atlanto-axial subluxation. The sagittal alignment of C1-C2 and the subaxial cervical spine was measured and the factors that affect subaxial alignment were investigated. Subaxial alignment became less lordotic in the postoperative course. The C1-C2 fixation angle and subaxial alignment showed a negative linear correlation. However, no significant correlation was found between changes in the C1-C2 angle and changes in the subaxial alignment. Four patients had a postoperative kyphotic subaxial deformity. Neurologic deterioration recurred in 4 patients, because of the postoperative development of subaxial subluxation. Common radiographic changes included an increase in C1-C2 lordosis, constant inclination of C1, an anterior shift of C2, and a decrease in C2-C7 lordosis. Many factors, not only C1-C2 angle, are associated with subaxial sagittal alignment change after C1-C2 transarticular screw fixation.