Seiichiro Shimada

Relationship between gait and clinical results after high tibial osteotomy

Thirty-two patients with primary osteoarthritis of the medial compartment of the knee were studied prospectively to assess the relationship between clinical results, limb alignment, and adduction moment of the knee. Clinical and radiographic examination and gait analyses were performed preoperatively and repeated at 6 months and at 1, 3, and 6 years after high tibial osteotomy. The preoperative peak adduction moment was high in 25 patients and low in seven. In both groups, the adduction moment of the knee decreased at 6 months after surgery but increased after that period. Alignment of the affected knee in both groups remained valgus after surgery (average femorotibial angle, 167°-169°). Clinical outcome in both groups improved after surgery and remained unchanged after 1 year. The peak adduction moment of the knee for the whole group significantly correlated with alignment and foot angle before and 6 years after surgery but did not correlate with stride length and walking velocity. In addition, only alignment was associated significantly with clinical results at 6 years. These results suggest that the preoperative peak adduction moment of the knee does not correlate with clinical or radiographic outcomes of high tibial osteotomy, provided sufficient valgus alignment is achieved at surgery.

Joint proprioception before and after total knee arthroplasty.

To investigate the effects of total knee arthroplasty on joint proprioception, the absolute angular error of the knee in 38 consecutive patients before and after total knee arthroplasty for osteoarthritis and in 23 age-matched control subjects were examined. Varus and valgus laxity of the knee and muscle strengths of the thigh were measured using appropriate instruments. There were no significant differences in absolute angular error before and after total knee arthroplasty, independent of retaining or substituting the posterior cruciate ligament. The absolute angular error of the knee with a normal appearing anterior cruciate ligament was larger than that with a missing anterior cruciate ligament before total knee arthroplasty and decreased significantly after surgery. The absolute angular error correlated with the varus and valgus laxity of the knee, but did not correlate with the strength of thigh muscles after total knee arthroplasty. These results suggest that deficiency of the anterior cruciate ligament may not adversely affect proprioception in severe knee osteoarthritis. In addition, proper ligament balance may partly contribute to better proprioception after total knee arthroplasty.

High-resolution magnetic resonance imaging and 18FDG-PET findings of the cervical spinal cord before and after decompressive surgery in patients with compressive myelopathy.

Study Design. Evaluation of cervical spinal cord (CSC) of patients with compressive myelopathy by magnetic resonance imaging (MRI) and high-resolution (18F)fluoro-deoxyglucose (18FDG) positron emission tomography (PET). Objective. To determine changes in morphology, intramedullary signal intensity, and glucose metabolic rate in CSC after decompression, and to assess the utility of 18FDG-PET in evaluation of patients with cervical myelopathy. Summary of Background Data. The significance of CSC enlargement after decompression and signal intensity changes within the cord remain elusive. No data are available on metabolic activity of the compressed CSC. Only a few studies have examined correlation between high-resolution MRI and 18FDG-PET neuroimaging in cervical myelopathy. Methods. We studied 24 patients who underwent cervical decompressive surgery in terms of postoperative neurologic improvement and changes in MRI and 18FDG-PET. Neurologic status was assessed by the Japanese Orthopedic Association scoring system (17-point scale). Signal intensity change in the cord was qualitatively assessed on both T1- and T2-weighted images. The transverse area of the CSC on MRIs and glucose metabolic rate (standardized uptake value [SUV]) from 18FDG-PET were measured digitally. Results. Neurologic improvement correlated with preoperative CSC transverse area at maximal compression (P < 0.01) and at follow-up (P < 0.001) and with mean SUV before surgery (P < 0.01) and at follow-up (P < 0.05). Preoperative signal intensity change on MRIs (low intramedullary signal intensity abnormality on T1-weighted image and high intramedullary on T2-weighted image) correlated negatively with neurologic improvement rate (P < 0.05). The transverse area of the CSC was significantly smaller after surgery in patients with preoperative MRI signal intensity changes (P < 0.05). The SUV at follow-up tended to normalize in association with neurologic improvement. Conclusion. Our results showed that postoperative neurologic improvement in patients with cervical compressive myelopathy correlated with increased transverse area of the spinal cord, signal intensity change on both T1- and T2-weighted image, and the mean SUV.

Early transcutaneous electrical nerve stimulation reduces hyperalgesia and decreases activation of spinal glial cells in mice with neuropathic pain.

Summary Application of early transcutaneous electrical nerve stimulation in a mouse model of neuropathic pain suppressed hyperalgesia and attenuated spinal microglial activation. ABSTRACT Although transcutaneous electrical nerve stimulation (TENS) is widely used for the treatment of neuropathic pain, its effectiveness and mechanism of action in reducing neuropathic pain remain uncertain. We investigated the effects of early TENS (starting from the day after surgery) in mice with neuropathic pain, on hyperalgesia, glial cell activation, pain transmission neuron sensitization, expression of proinflammatory cytokines, and opioid receptors in the spinal dorsal horn. Following nerve injury, TENS and behavioral tests were performed every day. Immunohistochemical, immunoblot, and flow cytometric analysis of the lumbar spinal cord were performed after 8 days. Early TENS reduced mechanical and thermal hyperalgesia and decreased the activation of microglia and astrocytes (P < 0.05). In contrast, the application of TENS at 1 week (TENS‐1w) or 2 weeks (TENS‐2w) after injury was ineffective in reducing hyperalgesia (mechanical and thermal) or activation of microglia and astrocytes. Early TENS decreased p‐p38 within microglia (P < 0.05), the expression levels of protein kinase C (PKC‐&ggr;), and phosphorylated anti‐phospho‐cyclic AMP response element‐binding protein (p‐CREB) in the superficial spinal dorsal horn neurons (P < 0.05), mitogen‐activated protein (MAP) kinases, and proinflammatory cytokines, and increased the expression levels of opioid receptors (P < 0.05). The results suggested that the application of early TENS relieved hyperalgesia in our mouse model of neuropathic pain by inhibiting glial activation, MAP kinase activation, PKC‐&ggr;, and p‐CREB expression, and proinflammatory cytokines expression, as well as maintenance of spinal opioid receptors. The findings indicate that TENS treatment is more effective when applied as early after nerve injury as possible.

Motor neuron involvement in experimental lumbar nerve root compression: a light and electron microscopic study.

Study Design. The aim of this study is to investigate changes in lumbar motor neurons induced by mechanical nerve root compression using an in vivo model. This study is to investigate the changes of lumbar motor neuron induced by mechanical nerve root compression using in vivo model. Objectives. The effect of axonal flow disturbance induced by nerve root compression was determined in lumbar motor neuron. Summary of Background Data. The lumbar motor neuron should not be overlooked when considering the mechanism of weakness, so it is important to understand the morphologic and functional changes that occur in motor neurons of the spinal cord as a result of nerve root compression. However, few studies have looked at changes of neurons within the caused by disturbance of axonal flow, the axon reaction, chromatolysis, and cell death as a result of mechanical compression of the ventral root. Methods. In mongrel dogs, the seventh lumbar nerve root was compressed for 1 week, or 3 weeks using a clip. Morphologic changes of the motor neurons secondary to the axon reaction were examined by light and electron microscopy. Results. Light and electron microscopy showed central chromatolysis of motor neurons in the lumbar cord from 1 week after the start of compression. After 3 weeks, some neurons undergoing apoptosis were seen in the ventral horn. Conclusion. It is important to be aware that, in patients with nerve root compression due to lumbar disc herniation or lumbar canal stenosis, dysfunction is not confined to degeneration at the site of compression but also extends to the motor neurons within the lumbar cord as a result of the axon reaction. Patients with weakness of lower leg should therefore be fully informed of the fact that these symptoms will not resolve immediately after surgery.

Visualization of intraneural edema using gadolinium-enhanced magnetic resonance imaging of carpal tunnel syndrome

BackgroundIn general, carpal tunnel syndrome (CTS) is diagnosed based mainly on clinical findings and electrophysiology. However, the pathological state of the compressed median nerve could not be shown on imaging. Gadoliniumenhanced magnetic resonance (MR) imaging may give us an idea about the status of the blood-nerve barrier of peripheral nerves. Therefore, detecting intraneural edema may be a way of diagnosing entrapment neuropathy. The present study investigated the diagnostic role of gadolinium-enhanced MR imaging of CTS.MethodsThe subjects were 23 patients (34 hands) with idiopathic CTS. To serve as control subjects, 12 wrists of asymptomatic volunteers were studied. Using the spin-echo method, T1- and T2-weighted axial MR images were obtained. Intravenously injected gadolinium was used to obtain enhanced images. We studied the relation between nerve enhancement and the symptomatology.ResultsAfter intravenous injection of gadolinium, there was no enhancement of the unaffected nerves in the carpal tunnels of the control group. Gadolinium enhancement was found in only 87% of patients with CTS who visited the hospital at an early stage and therefore had no nerve deficiency on electrophysiological studies (39%). Based on this finding, during the early stages when the nerve is in a state of neuropraxia, gadolinium-enhanced MR imaging of the median nerve might prove to be the most sensitive modality for detecting early nerve dysfunction. MR imaging also revealed a higher frequency of enhancement in the advanced stage of CTS with muscle atrophy.ConclusionsWe conclude that gadolinium-enhanced MR imaging can detect not only morphological changes but also pathological changes of the median nerve in patients with CTS. Currently, gadolinium-enhanced-MR imaging is probably most commonly used to image patients who have ambiguous electrodiagnostic studies and clinical examination in an early stage of CTS.

Lidocaine cytotoxicity to the zygapophysial joints in rabbits: changes in cell viability and proteoglycan metabolism in vitro.

Study Design. To examine whether lidocaine cytotoxicity to chondrocytes has been implicated in the development of osteoarthritis of the zygapophysial joints. Objective. This study was performed to determine the effects of varying concentrations and exposure times of lidocaine on the viability and proteoglycan metabolism of rabbit zygapophysial chondrocytes in vitro. Summary of Background Data. Zygapophysial joint injections are commonly administered with lidocaine for chronic spinal pain in orthopedic treatment. A lot of studies on the effect of zygapophysial joint injections are clinical, but many questions on the effect of lidocaine to zygapophysial chondrocytes remain unanswered. Methods. Cartilage was obtained from zygapophysial joints of adult rabbits. Chondrocytes in alginate beads were cultured in medium containing 6% fetal calf serum at 370 mOsmol at cell densities of 4 million cells/mL. They were then cultured for 24 hours under 21% oxygen with 0.125%, 0.25%, 0.5%, and 1% lidocaine, and without lidocaine as control. The cell viability profile across intact beads was determined by manual counting using fluorescent probes (LIVE/DEAD assay) and transmission electron microscopy. Lactate production was measured enzymatically as a marker of energy metabolism. Glycosaminoglycan (GAG) accumulation was measured using a modified dimethylmethylene blue assay. Results. Cell viability decreased in a time- and dose-dependent manner in the concentration range of 0.125% to 1.0% lidocaine under the confocal microscope. Under the electron microscope, apoptosis increased as the concentration of lidocaine increased. GAG accumulation/tissue volume decreases as the concentration of lidocaine increased. However, GAG produced per million cells and the rate of lactate production per live cell was significantly higher for cells cultured at 0.5% and 1% lidocaine than the control group. Conclusion. While these in vitro results cannot be directly extrapolated to the clinical setting, this data suggestcaution in prolonged exposure of zygapophysial cartilage to high concentration lidocaine.

Changes in Gait Pattern and Hip Muscle Strength After Open Reduction and Internal Fixation of Acetabular Fracture

OBJECTIVES To characterize changes in the gait pattern at 3 and 12 months after surgery for acetabular fracture, to assess the relationship between various gait parameters and hip muscle strength, and to determine the factors associated with gait disorders that correlate with gait parameters measured at 12 months after surgery. DESIGN Prospective cohort study. SETTING University hospital. PARTICIPANTS Patients (N=19) with acetabular fractures were treated by open reduction and internal fixation (ORIF) and examined at 3 and 12 months postoperatively. The study also included a similar number of sex- and age-matched control subjects. INTERVENTIONS Postoperative rehabilitation program. MAIN OUTCOME MEASURES Spatiotemporal, kinematic, and kinetic variables of gait and strength of hip flexor, adductor, and abductor muscles at 3 and 12 months after ORIF. RESULTS Walking velocity at 3 months after ORIF was slower in the patients than in the control subjects; however, walking velocity at 12 months was similar in the 2 groups. Although most of the kinematic and kinetic variables showed recovery to control levels at 3 and 12 months after ORIF, recovery was incomplete for pelvic forward tilt and hip abduction moment even at 12 months after ORIF. The greatest loss of muscle strength was noted in the hip abductors, where the average deficit was 35.4% at 3 months and 24.6% at 12 months. There was a significant relationship between hip abductor muscle strength and hip abduction moment at 3 months (R(2)=.63); however, this relationship diminished at 12 months (R(2)=.14). The presence of associated injuries correlated with lack of recovery of the peak hip abduction moment. CONCLUSIONS Pelvic forward tilt and peak hip abduction moment showed incomplete recovery at 12 months after ORIF with subsequent conventional and home exercise rehabilitation programs. Our results suggest that improvement of hip abductor muscle strength in the early postoperative period could improve the peak hip abduction moment.

Effect of compensation procedures for velocity on repeatability and variability of gait parameters in normal subjects

Objective: To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis. Design: Evaluation before and after compensation. Setting: Gait laboratory, Fukui University Hospital, Japan. Subjects: Fourteen normal volunteers. Outcome measures: A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days. Results: The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters. Conclusions: Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.

Knee laxity after staircase exercise predicts radiographic disease progression in medial compartment knee osteoarthritis

OBJECTIVE To evaluate whether increased laxity of the knee during daily physical activities such as stair climbing is associated with progression of knee joint osteoarthritis (OA). METHODS During the years 2001-2003, 136 patients with bilateral primary medial compartment knee joint OA were enrolled in this prospective study. Baseline data collected were body mass index (BMI), muscle power, radiographic joint space width, mechanical axis on standing radiography, and anteroposterior (AP) knee laxity before and after physical exercise. After 8 years of followup, 84 patients were reexamined to assess radiographic changes. Radiographic disease progression was defined as progression of >1 grade on the Kellgren/Lawrence scale. RESULTS AP knee laxity increased significantly after stair climbing. Patients with OA progression and those without progression did not differ significantly in age, sex, baseline quadriceps muscle strength, mechanical axis, joint space width, and AP knee laxity before exercise. The 2 groups of patients did, however, differ significantly in baseline BMI and change in AP knee laxity due to exercise. The risk of progression of knee OA increased 4.15-fold with each millimeter of increase in the change in AP knee laxity due to exercise and 1.24-fold with each point increase in the BMI. CONCLUSION Our results indicate that patients with OA progression have significantly greater changes in knee joint laxity during physical activities and a higher BMI than patients without OA progression. These findings suggest that larger changes in knee laxity during repetitive physical activities and a higher BMI play significant roles in the progression of knee OA.