Comparison of three techniques for evaluation of de novo asymptomatic pulmonary arterial thrombosis following deep vein thrombosis in total knee arthroplasty.

PURPOSE: Deep venous thrombosis (DVT) following total knee arthroplasty (TKA) frequently results in pulmonary arterial thrombosis (PAT). Using multislice-CT (MSCT), we evaluated the incidence of de novo asymptomatic PAT following DVT in subjects undergoing TKA and compared these results by ventilation-perfusion (VP) lung scintigram and ultrasonography of the lower extremities. MATERIALS AND METHODS: Twenty-five asymptomatic subjects (5 males, 53-82 years old, receiving anticoagulant therapy) underwent enhanced MSCT, VP lung scintigram, and ultrasonography of the lower extremities before and 7 days after TKA. RESULTS: Among 25 subjects, 2 were found to have asymptomatic PAT and DVT, respectively, by pre-TKA MSCT. In the remaining 23 subjects, the post-TKA MSCT detected PAT in 7 subjects (30.4%) and DVT in 6 (26.1%). Those 16 subjects without evidence of PAT on the post-TKA MSCT also had no VP mismatches on their VP lung scintigrams. Additionally, all subjects without evidence of DVT on the post-TKA MSCT also showed no evidence of DVT by ultrasonography. Of the 7 subjects in whom PAT was detected by post-TKA MSCT, VP mismatch was shown by lung scintigraphy in 2 and DVT was confirmed by MSCT in both. No patient had VP mismatch without PAT, and 2 subjects with PAT and VP mismatch had DVT. Conversely, DVT was not revealed by ultrasonography among the 6 subjects (26.1%) in whom DVT was detected in the lower extremities by post-TKA MSCT. However, blood flow abnormalities were shown by ultrasonography of the lower extremities in 4 of the 6 subjects (17.4%). CONCLUSION: MSCT was the most sensitive of the 3 methods and could simultaneously evaluate PAT and DVT. The apparent discrepancy between these techniques may be due to MSCT's ability to detect thrombi that do not interfere with blood flow.

Evaluation of low back pain using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire for lumbar spinal disease in a multicenter study: differences in scores based on age, sex, and type of disease.

BACKGROUND: The Japanese Orthopaedic Association (JOA) has investigated the JOA Back Pain Evaluation Questionnaire (JOABPEQ) to evaluate several aspects of low back pain in patients. The score includes five categories (25 items) selected from the Roland Morris Disability Questionnaire and Short Form 36, and a visual analogue scale. Japanese physicians have recently used these scores to evaluate back pain; however, the efficacy has not been fully explored in large-scale studies. In the current study, we used the JOABPEQ to evaluate lumbar spinal disease in 555 patients (with lumbar disc herniation, lumbar spinal stenosis, and lumbar disc degeneration/spondylosis) in multiple spine centers and compared the results based on age, sex, and type of disease. METHODS: A total of 555 patients who had low back or leg pain were selected in 22 hospitals in Chiba Prefecture. Spine surgeons diagnosed their disease type based on symptoms, physical examination, radiography images, and magnetic resonance imaging. In all, 486 patients were diagnosed with spinal stenosis (239 patients), disc degeneration/spondylosis (143 patients), or disc herniation (104 patients). The other 69 patients were diagnosed with spondylolysis (16 patients) or other diseases (53 patients). The pain score in all patients was evaluated using the JOABPEQ (from 0 to 100, with 0 indicating the worst pain). RESULTS: The age of the patients was 56.1 +/- 13.3 years (mean +/- SD); the age of patients in the disc herniation and disc degeneration/spondylosis group was significantly lower than that in the spinal stenosis group. The average JOABPEQ scores in all patients were, for low back pain, 47.1; lumbar function, 53.6; walking ability, 54.8; social life function, 48.7; and mental health, 48.3. The low back pain score in men was significantly worse than that in women. In contrast, the mental health score in women was significantly higher than that in men. The low back pain score in patients <40 years old and the walking ability score in patients >65 years old were significantly lower than those scores in other patients. Based on the disease type, low back pain, lumbar function, social life function, and mental health scores for patients with disc herniation were significantly worse than for those with spinal stenosis. CONCLUSION: JOABPEQ scores were evaluated for several lumbar diseases. The average of five categories of JOABPEQ scores in all patients was similarly distributed. However, the average scores in the five categories were significantly different depending on age, sex, and type of disease. Compared with prior mass data (baseline data on the observational cohort of the Spine Patient Outcomes Research Trial in the United States), many data were similar based on the type of disease in the current study. Furthermore, the JOABPEQ is easy to use compared with the SF-36. Hence, we concluded that the JOABPEQ could be used worldwide as a tool for evaluating low back pain.

Evaluation of joint laxity against distal traction force upon flexion in cruciate-retaining and posterior-stabilized total knee arthroplasty.

BACKGROUND: Several studies have reported varus-valgus stability in the extension position after total knee arthroplasty (TKA). However, few studies have evaluated joint laxity in the flexion position postoperatively. The purpose of the study was to evaluate joint laxity against distal traction force on flexion after cruciate-retaining and posterior-stabilized total knee arthroplasties. METHODS: A total of 44 knees (22 knees cruciate-retaining, 22 knees posterior-stabilized) in 40 patients with osteoarthritis were tested in this study. The subjects were seated at a table and their knee joints were fixed at 80 degrees of flexion to avoid overlapping images of condyles and the femoral shaft. Tibial shafts were adjusted to be parallel to the radiographic films, and posteroanterior radiographs were obtained. Flexion stress tests were performed with a distal traction of 100 N at a neutral foot position. Radiographs were obtained at neutral and traction positions. The distance from the perpendicular line of the top of the polyethylene insert to the midpoint on the tangential line of the femoral condyle was measured (joint space distance) at each side. RESULTS: In the flexion-neutral position, average joint space distances were 0.1 +/- 0.2 mm in cruciate-retaining (CR) TKA knees and 0.2 +/- 0.3 mm in posterior-stabilized (PS) TKA knees. With flexion-traction stress tests, the average joint space distances were 0.5 +/- 0. 5 mm in CR TKA knees 2.4 +/- 1.2 mm in PS TKA knees. Average changes of joint space distances between the two positions were 0.3 +/- 0.4 mm (CR TKA) and 2.2 +/- 1.5 mm (PS TKA). The changes in joint space distances between neutral and traction positions of PS TKA knees were significantly larger than those of CR TKA knees in flexion stress tests (P < 0.01). CONCLUSION: The posterior cruciate ligament acted as a stabilizer against distal traction force in the CR-TKA knees. However, the laxity of PS-TKA knees against distal force differed among individual cases.

Predictive indicators of deep venous thrombosis and pulmonary arterial thromboembolism in 54 subjects after total knee arthroplasty using multislice computed tomography in logistic regression models.

PURPOSE: To determine predictors of deep venous thrombosis (DVT) in the lower extremities and pulmonary arterial thromboembolism (PE) after total knee arthroplasty (TKA), we evaluated the incidence of these events using multislice computed tomography (CT). METHODS: 54 subjects (10 males, 53-81 years old, the first consecutive 25 receiving anticoagulant therapy) underwent enhanced multislice CT (MSCT) before and one week after TKA. RESULTS: DVT, PE, and both were detected in twelve, twelve, and three subjects, respectively, one week after TKA. Hemoglobin and alveolar-arterial oxygen gradient (AaDO2) on the day after TKA, and total amount of operative bleeding (TAOB) were significantly higher in subjects with DVT or PE (P<0.05). In a logistic model for predicting DVT or PE, hemoglobin and AaDO2 levels on the day after TKA and TAOB were associated with an increased incidence of DVT or PE (relative risks 3.51, 1.19 and 1.01 (P<0.05), respectively). From box and whisker plots, we speculated the significant border to predict DVT or PE as 10.5 g/dl for hemoglobin, 34 Torr for AaDO2, and 1280 ml for TAOB. These factors also predicted DVT or PE (relative risks 5.08 (hemoglobin more than 10.5), 6.25 (AaDO2 more than 34 Torr), and 4.95 (TAOB more than 1280 ml) (P<0.05)). CONCLUSIONS: The incidence of DVT or PE one week after TKA was 39% by MSCT. High levels of TAOB, hemoglobin and AaDO2 on the day after TKA may be predictive indicators of DVT or PE one week after TKA.

A case of spontaneous hemoarthrosis after a total knee arthroplasty.

A 63-year-old woman with osteoarthritis had undergone right total knee arthroplasty. Nineteen months later, the patient presented with a recurrent hemoarthrosis. Open arthrotomy revealed hypertrophic synovium with small clots in the suprapatellar pouch, but entrapment of synovial tissues could not be observed. Histological examination of the extirpated specimen showed fibrous hypertrophy of synovium. The patient has no symptoms 51 months after surgery.

Mechanical and histological evaluation of a PMMA-based bone cement modified with gamma-methacryloxypropyltrimethoxysilane and calcium acetate.

Polymethylmethacrylate (PMMA) bone cement is widely used for prosthetic fixation in orthopaedic surgery; however, the interface between bone and cement is a weak zone. We developed a bioactive PMMA cement through modification with gamma-methacryloxypropyltrimethoxysilane (MPS) and calcium acetate. The purpose of this study was to compare the handling, mechanical and histological properties of the modified bone cement with those of the conventional cement. The modified specimens exhibited higher bonding strength between bone and implant. Histological observation and micro-focus X-ray computed tomogram (micro-CT) images showed that the modified cement exhibited osteoconduction, which the conventional PMMA bone cement lacked. The modification was found to be effective in enabling osteoconduction with PMMA bone cement, thus providing stable fixation for a long period after implantation.

Enhanced fixation of implants by bone ingrowth to titanium fiber mesh: effect of incorporation of hydroxyapatite powder.

Tight fixation between bone and implant materials is of great importance for a successful outcome of procedures such as total knee arthroplasty (TKA) and total hip arthroplasty (THA). Titanium fiber mesh is an attractive structure for the establishment of tight fixation between bone and implant by bone ingrowth into the spaces among the fibers. Enhancement of bone ingrowth is desired not only for tight fixation but also for a fast recovery. Our hypothesis is that just the presence of hydroxyapatite (HA) particles ensures improved bone ingrowth, and that long-term stability can be obtained by mechanical anchoring of bone in the spaces among titanium fibers. In this study, we examine our hypothesis by in vivo experiment using dog femur. HA particles were incorporated in titanium fiber mesh coated on titanium alloy rod by dipping in a slurry of HA with hydroxy-propyl-cellulose in an ethanol solution. Specimens were implanted for 3, 5, and 8 weeks, and were then compared with the results from specimens without the use of HA. Bonding strength was evaluated by push-out test, and histomorphometric measurements were made with analysis software to calculate the average value of bone ingrowth. A significantly higher bonding strength was observed for the specimens with HA-incorporated implant at 3 and 5 weeks, and larger bone ingrowth deep inside the titanium fiber mesh was measured at 3 weeks. Our proposed method has the additional advantage of not requiring a high temperature that may result in changes in characters of HA powder such as phase transition, grain growth, and decomposition. Moreover, this technique of HA powder incorporation without high-temperature treatment allows the use of several types of metallic fiber mesh, as well as the application to fiber mesh made of organic polymers. We conclude that this simple modification of titanium fiber mesh with HA powder can improve the fixation of implant to bone in the initial stage after operation.