Anteroposterior stability in posterior cruciate ligament-retaining total knee arthroplasty

Anteroposterior stability was evaluated using a KT-2000 arthrometer in 18 patients (21 knees) continuously for up to 5 years after posterior cruciate ligament-retaining total knee arthroplasty. The Knee Society score, functional score, and the maximum flexion angle did not change significantly during the postoperative period. The mean anteroposterior displacement of all joints studied at both 30 degrees and 75 degrees of flexion did not change significantly during the 5-year period of observation, but 4 individual knees did exhibit increases in anteroposterior displacement of 3 mm or more. One of the 4 knees exhibited osteolysis beneath the tibial component. Three of these knees had undergone high tibial osteotomy at some time before the total knee arthroplasty.     

Temozolomide in the treatment of recurrent malignant glioma

Temozolomide (TMZ) has demonstrated activity and acceptable toxicity for the treatment of recurrent malignant gliomas in carious prospective phase II studies. No information is, however, available on TMZ treatment for recurrent malignant glioma in Japanese patients. We report Hokkaido University Hospital experience on 35 adult patients with a recurrent malignant glioma, including 13 glioblastomas, 9 anaplastic astrocytomas, and 13 anaplastic oligondendroglial tumors. The median age was 52 years. The starting dose of TMZ was 150 mg/m2/day for 5 days. When no remarkable toxicity was observed, the dose was increased to 200 mg/m2 for subsequent cycles, every 4 week. In the 35 patients, the overall objective response rate (partial response) was 12% and 74% of the patients achieved disease stabilization. The median progression-free survival was 28 weeks and the median overall survival was 43 weeks. Although hematological toxicity was the most frequent adverse event (CTC grade 3 or 4 in 6 patients), overall toxicity was generally mild. Four patients required hospitalization due to the toxicity, but 28 patients had been treated with TMZ at our outpatient clinic. These results suggested that the reported efficacy and toxicity profile of TMZ for the treatment of Japanese patients with recurrent malignant glioma is reproducible from the setting of clinical trials in the western countries.     

Stabilization of the proximal ulnar stump in the Sauvé-Kapandji procedure by using the extensor carpi ulnaris tendon: long-term follow-up studies

PURPOSE: The Sauvé-Kapandji procedure is considered a useful treatment option for distal radioulnar disorders. Postoperative instability of the proximal ulnar stump and radioulnar convergence, however, may be symptomatic. We modified the Sauvé-Kapandji procedure by stabilizing the proximal ulnar stump with a half-slip of the extensor carpi ulnaris tendon. We previously reported on 13 patients with this procedure at an average follow-up period of 35 months; the patients had satisfactory clinical results and improved stability of the proximal ulnar stump as shown by x-ray examination. In this article we address the question of whether those clinical and radiographic results noted at an average follow-up period of 35 months after surgery were maintained at later follow-up examinations. METHODS: We re-examined 12 of the 13 original patients and compared their initial follow-up results with their current results after an average follow-up period of 95 months. RESULTS: The results of this series after 95 months of follow-up evaluation were similar to the results at 35 months. CONCLUSIONS: The results presented in this article suggest that the clinical radiographic results at the 35-month follow-up examination were maintained in the long-term 95-month follow-up evaluation despite the finding that the hole in the proximal ulnar stump had broken in 3 wrists at follow-up examination. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.     

Numerical analysis of cooperative abduction muscle forces in a human shoulder joint

Because some shoulder muscles originate from a wide area, the modeling of such muscles has been a significant problem in a computer simulation. We demonstrated a new method of determining a vector for each of the muscles originating from a wide area. A 3-dimensional musculoskeletal model of a human shoulder was constructed from computed tomography data of a normal volunteer. Numerical analysis of 11 muscle forces and the joint reaction force during shoulder abduction from 10 degrees to 150 degrees was performed from the static equilibrium equations. An optimal origin point for the vector of the muscle with a wide origin area was determined in every analyzed position. Electromyography was carried out to validate the results of the simulation, and a significant correlation with the analyzed force was obtained in each muscle. The anatomic biomechanical model with the new muscle modeling method led to the results reflecting the actual muscle activities in a living body.     

How does spontaneous hemostasis occur in ruptured cerebral aneurysms? Preliminary investigation on 247 clipping surgeries

BACKGROUND: Rupture of cerebral aneurysms results in subarachnoid hemorrhage. In many cases, bleeding from aneurysms spontaneously arrests. Although bleeding from cerebral aneurysms has been reported to arrest from outside, bleeding from some aneurysms can arrest in different ways. METHODS: Between April 2002 and March 2004, we prospectively investigated mechanisms of spontaneous hemostasis in ruptured aneurysms by macroscopic examination when performing craniotomy and clipping surgeries. RESULTS: Hemostatic mechanisms were investigated in 247 patients with ruptured aneurysm (77 men, 170 women; age range, 25-95 years). Hemostatic mechanisms were divided into 3 different patterns. In the most common pattern (79.4%), the surface of the aneurysm rupture point was sealed from the outside by a platelet plug or fibrin net (outside-arrest pattern). In some aneurysms (10.1%), a thrombus or platelet plug was attached to the rupture point from inside the aneurysm (inside-arrest pattern). In a very small number of aneurysms (1.6%), a naked thrombus covered the hole made on the arterial wall or small remnant of the aneurysmal dome (bursting pattern) The mechanism remained unclear in the remaining 8.9% of aneurysms. Multivariate analysis revealed that alert consciousness on admission (WFNS grade I) significantly associated with usual hemostasis (outside arrest pattern: OR, 3.8; 95% CI, 1.4-10.0; P = .008). Borderline association with usual hemostasis was found in aneurysms with a size of 5 or smaller than 5 mm (OR, 2.6; 95% CI, 0.99-7.1; P = .052). CONCLUSIONS: The present preliminary study revealed that arrest of bleeding from a ruptured cerebral aneurysm does not always occur from outside the aneurysm. Unusual mechanisms of hemostasis are seen in approximately 12% of ruptured aneurysm. The outside-arrest-pattern aneurysm was more common for smaller aneurysms, and these patients tended to be of better grade. Further studies are necessary to explore the mechanism of hemostasis for ruptured cerebral aneurysms.     

Surgical stabilization of multiple rib fracture and flail chest

The experience of 14 cases with surgical stabilization of multiple rib fracture and flail chest was reported. They were 11 men and 3 women of 31 to 87 years of age. Paradoxical chest movement was noted in 10 patients. Thirteen of 14 patients successfully weaned from the ventilator less than 7 days after surgery. Of 14, 4 cases were treated with internal fixation and the others were with acetabular reconstruction plates with or without rib stapler. No case of death was experienced. Ten patients who were performed fixation with acetabular reconstruction plate weaned from the ventilator earlier than cases treated by internal fixation, suggesting the superiority of the acetabular reconstruction plate. Improvement of rib stapler and the development of a titanium plate of specific use for rib is expected in the future.     

Pharmacokinetic simulation of high-dose administration of dexmedetomidine for decubitus treatment

We used only dexmedetomidine to sedate a patient with Alzheimer disease, Parkinson's syndrome and emaciation for decubitus treatment in the prone position. The infusion rate of dexmedetomidine without a loading dose was increased until sufficient sedation was attained. The maximum plasma concentration and the plasma concentration in a stable state, which were calculated by pharmacokinetic simulation analysis, were 2.3 ng x ml(-1) and 1.5 ng x ml(-1), respectively. Respiration disorder did not occur and hemodynamic stability was preserved despite administration up to 11.5 mcg x kg(-1) x h(-1). An increase in the dose per weight was needed to increase the absolute dose because of emaciation. It was found by pharmacokinetic simulation analysis that the plasma concentration of dexmedetomidine required for decubitus treatment might be higher than the plasma concentration considered to be necessary for sedation in intensive care units. The simulation was conducted to administer dexmedetomidine, to estimate hemodynamic reaction, and to estimate the necessary plasma concentration. We conclude that dexmedetomidine is useful as an anesthetic agent for decubitus treatment in the prone position, although further investigations with regard to its safety are required.