中村 順一

STUDY DESIGN: Immunohistological analysis of dichotomizing sensory nerve fibers projecting to the lumbar multifidus muscles and intervertebral disc (IVD), facet joint (FJ), or sacroiliac joint (SIJ) in rats. OBJECTIVE: To elucidate dichotomizing sensory nerve fibers projecting to the lumbar multifidus muscles and to IVDs, FJs, or SIJs. SUMMARY OF BACKGROUND DATA: Clinically, the origin of low back pain remains unknown. Multiple studies have identified lumbar muscles, IVDs, FJs, and SIJs as sources of low back pain. Pain may originate directly from lumbar muscles or be referred from the spine, or both. Dorsal root ganglion (DRG) neurons with dichotomizing axons have been reported in several species and are thought to be related to referred pain. METHODS: We used 2 neurotracers, 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) and fluorogold (FG), in this double-labeling study involving 30 Sprague Dawley rats. DiI was applied to lumbar multifidus muscles in all rats. Simultaneously, FG was applied to the anterior left portion of L5-L6 IVDs in the IVD group (n = 10), to the left L5-L6 FJs in the FJ group (n = 10), and to the left SIJs in the SIJ group (n = 10). Fourteen days after surgery, left DRGs from L1 to L6 were harvested, sectioned, and observed under a fluorescence microscope. RESULTS: We verified the existence of double-labeled DRG neurons (i.e., dichotomizing sensory nerve fibers) projecting to lumbar multifidus muscles and to IVDs, FJs, or SIJs, depending on the group. The proportion of double-labeled cells in all DiI-labeled DRG neurons was higher in the FJ group (6.8%) and SIJ group (7.1%) than in the IVD group (3.1%) (P < 0.05). CONCLUSION: Our results document the presence of dichotomizing sensory nerve fibers projecting to lumbar multifidus muscles and to IVDs, FJs, and SIJs. Referred low back muscle pain may reflect disorders of lumbar posterior structures, such as FJs and SIJs, rather than disorders of lumbar anterior structures, such as IVDs.

OBJECTIVE: The purpose of the study was to clarify the incidence of alcohol-associated osteonecrosis of the knee using MRI. METHODS: A total of 131 patients (56 women and 75 men) with osteonecrosis of the femoral head were enrolled; 60 patients had a history of alcohol abuse and 71 had previously received steroids. All patients underwent MRI of the knee. The incidence of alcohol-associated osteonecrosis of the knee was compared with that of steroid-associated osteonecrosis of the knee. Predictive factors of alcohol- and steroid-associated osteonecrosis of the knee were also evaluated. RESULTS: The incidence of alcohol-associated osteonecrosis of the knee was lower than that of steroid-associated osteonecrosis of the knee (18.3 vs 54.9%; P < 0.001, Fisher's exact probability test). No significant difference in weekly alcohol consumption was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. No significant difference in daily maximum steroid doses was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. CONCLUSION: The present study revealed that the incidence of alcohol-associated osteonecrosis of the knee is lower than that of steroid-associated osteonecrosis of the knee.

STUDY DESIGN: Prospective randomized trial. OBJECTIVE: To examine the effect of the tumor necrosis factor alpha (TNF-α) inhibitor, etanercept, on radicular pain by its epidural administration onto spinal nerves in patients with lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: TNF-α is thought to play a crucial role in the radicular pain caused by lumbar disc herniation and spinal stenosis. Intravenous infusion of infliximab for sciatica has been examined in 2 studies; however, the results were equivocal. METHODS: Eighty patients with low back and radicular leg pain were investigated. We diagnosed the patients by physical examination, and X-ray and magnetic resonance imaging. In 40 patients, we epidurally administered 2.0 mL of lidocaine and 10 mg of etanercept onto the affected spinal nerve, and 2.0 mL of lidocaine and 3.3 mg of dexamethasone was used in 40 patients. Low back pain, leg pain, and leg numbness were evaluated using a visual analogue scale (VAS) and Oswestry Disability Index (ODI) score before and for 1 month after epidural administration. RESULTS: Low back pain, leg pain, and leg numbness in the 2 groups were not significantly different before epidural administration. Epidural administration of etanercept was more effective than dexamethasone for leg pain (3 days, and 1, 2, and 4 weeks: P < 0.05), low back pain (3 days, and 1 and 2 weeks: P < 0.05), and leg numbness (3 days, and 1 and 2 weeks: P < 0.05). No adverse event was observed in either group. CONCLUSION: Our results indicate that epidural administration of a TNF-α inhibitor onto the spinal nerve produced pain relief, but no adverse event. TNF-α inhibitors may be useful tools for the treatment of radicular pain caused by spinal stenosis.

Disturbance of blood supply to the femoral head is a risk factor for corticosteroid-associated osteonecrosis. The aim was to measure blood supply of the proximal femur during corticosteroid therapy in systemic lupus erythematosus (SLE) patients. We repeatedly performed 78 dynamic MRIs of 19 hip joints in 19 SLE patients after initiation of corticosteroid administration for one year. Blood supply of the femoral head (epiphysis, growth plate, and metaphysis), the femoral neck, and the medial circumflex femoral artery were measured in terms of peak percent enhancement. At the first month, blood supply of the growth plate was significantly higher in the pediatric group (&lt;15 years old) than in the adolescent and adult group (&gt;15 years old). At the fourth month, blood supply in every part of the femoral head (epiphysis, growth plate, and metaphysis) was significantly higher in the pediatric group than in the adolescent and adult group. Multiple regression analysis revealed that blood supply to the femoral head depended on the number of days after initiation of corticosteroid administration and the age at the time of dynamic MRI. Blood supply to the femoral head is abundant in pediatric patients and is a function of the number of days after initiation of corticosteroid administration.

PURPOSE: Sacroiliac fixation using iliac screws for highly unstable lumbar spine has been reported with an improved fusion rate and clinical results. On the other hand, there is a potential for clinical problems related to iliac fixation, including late sacroiliac joint arthritis and pain. MATERIALS AND METHODS: Twenty patients were evaluated. Degenerative scoliosis was diagnosed in 7 patients, failed back syndrome in 6 patients, destructive spondyloarthropathy in 4 patients, and Charcot spine in 3 patients. All patients underwent posterolateral fusion surgery incorporating lumbar, S1 and iliac screws. We evaluated the pain scores, bone union, and degeneration of sacroiliac joints by X-ray imaging and computed tomography before and 3 years after surgery. For evaluation of low back and buttock pain from sacroiliac joints 3 years after surgery, lidocaine was administered in order to examine pain relief thereafter. RESULTS: Pain scores significantly improved after surgery. All patients showed bone union at final follow-up. Degeneration of sacroiliac joints was not seen in the 20 patients 3 years after surgery. Patients showed slight low back and buttock pain 3 years after surgery. However, not all patients showed relief of the low back and buttock pain after injection of lidocaine into the sacroiliac joint, indicating that their pain did not originate from sacroiliac joints. CONCLUSION: The fusion rate and clinical results were excellent. Also, degeneration and pain from sacroiliac joints were not seen within 3 years after surgery. We recommend sacroiliac fixation using iliac screws for highly unstable lumbar spine.

STUDY DESIGN: Immunohistochemical study. OBJECTIVE: To evaluate invasive surgical approaches by analyzing the number of sensory nerve fibers at 2 back muscle sites in rats and humans and the number of injured nerve fibers innervating these 2 sites after muscle injury in rats. SUMMARY OF BACKGROUND DATA.: Several minimally invasive approaches have recently become popular in the treatment of lumbar spine disorders. Minimally invasive surgery (MIS) is not invasive to back muscle and is thought to reduce low back pain. Muscle damage has been generally evaluated by magnetic resonance imaging (MRI); however, damage to sensory nerve fibers in and around back muscle that is directly related to pain has apparently not been explored. METHODS: Human muscle at L4-L5 was obtained from the paraspinous process (during a midline approach) and from paraspinal back muscle (during a Wiltse paraspinal approach) (n = 10 each). The muscle was sectioned and immunostained for calcitonin gene-related peptide (CGRP). To detect dorsal root ganglion (DRG) neurons innervating back muscle in rats, Fluoro-Gold (FG) was applied to the same 2 sites on the lower back muscle at L4-L5 (only application, n = 12; application of FG + muscle injury, n = 12). DRGs were harvested and immunostained for CGRP and activating transcription factor-3 (ATF-3: marker for nerve injury). The numbers of FG-labeled CGRP-immunoreactive or FG-labeled ATF-3-immunoreactive DRG neurons innervating the 2 sites were counted and compared. RESULTS: CGRP-immunoreactive sensory nerve fibers were found at the 2 sites. The average number of CGRP-immunoreactive sensory nerve fibers in muscle obtained in a midline approach was significantly higher than that in muscle obtained in a Wiltse paraspinal approach (P < 0.01). The numbers of FG-labeled CGRP- and ATF-3-immunoreactive DRG neurons innervating paraspinous process muscle were significantly greater than those innervating paraspinal back muscle in rats (P < 0.01). CONCLUSION: There are more CGRP-immunoreactive sensory nerve fibers and DRG neurons innervating muscle in the midline approach area than in the Wiltse paraspinal approach area in humans and rats. There are more ATF-3-immunoreactive DRG neurons innervating muscle in the midline approach area than in the Wiltse paraspinal approach area after muscle injury in rats. This result may show the differences in sensory nerve injury during the 2 surgical approaches.

STUDY DESIGN: Prospective study of 212 patients with groin pain but without low back pain. OBJECTIVE: To evaluate discogenic groin pain without low back pain or radicular pain. SUMMARY OF BACKGROUND DATA: Patients feel low back pain originating from discogenic disease. It has been reported that the rat lower lumbar discs are innervated mainly by L2 dorsal root ganglion neurons. Thus, it is possible that patients feel referred groin pain corresponding to the L2 dermatome originating from intervertebral discs; however, the referred pain has not been fully clarified in humans. METHODS: We selected 5 patients with groin pain alone for investigation. The patients suffered from groin pain and showed disc degeneration only at 1 level (L4-L5 or L5-S1) on magnetic resonance imaging. Patients did not show any hip joint abnormality on radiography or magnetic resonance imaging. To prove that their groin pain originated in degenerated intervertebral discs, we evaluated changes in groin pain after infiltration of lidocaine into hip joints and examined pain provocation on discography, pain relief by anesthetic discoblock, and finally anterior lumbar interbody fusion surgery. RESULTS: All patients were negative for hip joint block, positive for pain provocation on discography, and positive for pain relief by anesthetic discoblock. Furthermore, bony union was achieved 1 year after anterior interbody fusion surgery in all patients, and visual analogue scale score of groin pain was significantly improved at 1 year after surgery in all patients (P < 0.05). CONCLUSION: In the current study, we diagnosed discogenic groin pain, using magnetic resonance imaging, infiltration of lidocaine into the hip joint, pain provocation on discography, pain relief by anesthetic discoblock, and lumbar surgery. It is important to consider the existence of discogenic groin pain if patients do not show low back pain.

<sec><title>Objectives</title> The purpose of this study was to assess N-acetyl aspartate changes in the thalamus in patients with osteoarthritis of the hip using proton magnetic resonance spectroscopy. </sec><sec><title>Methods</title> Nine patients with osteoarthritis of the hip (symptomatic group, nine women; mean age 61.4 years (48 to 78)) and nine healthy volunteers (control group, six men, three women; mean age 30.0 years (26 to 38)) underwent proton magnetic resonance spectroscopy to assess the changes of N-acetyl aspartate in the thalamus. </sec><sec><title>Results</title> The ratio of N-acetyl aspartate to creatine plus phosphocreatine in the thalamus contralateral to the symptomatic hip in patients with osteoarthritis of the hip was significantly lower than the ratio of N-acetyl aspartate to creatine plus phosphocreatine in the thalamus in the control group (1.611 (1.194 to 1.882) vs 1.355 (1.043 to 1.502), p &lt; 0.001). And, a strong negative correlation was detected between the ratio of N-acetyl aspartate to creatine plus phosphocreatine in the thalamus contralateral to the symptomatic hip in patients with osteoarthritis of the hip and pain duration (r = -0.83, p = 0.018). </sec><sec><title>Conclusions</title> We evaluated the ratio of N-acetyl aspartate to creatine plus phosphocreatine in the thalamus of patients with osteoarthritis of the hip by using proton magnetic resonance spectroscopy. We concluded that the ratio of N-acetyl aspartate to creatine plus phosphocreatine in the thalamus contralateral to the symptomatic hip in patients with osteoarthritis of the hip were significantly lower than those in the thalamus of the control group, and that pain duration was strongly related to the decrease of the ratio of N-acetyl aspartate to creatine plus phosphocreatine. </sec>

STUDY DESIGN: Prospective trial. OBJECTIVE: To examine the bone union and clinical results after unilateral or bilateral instrumented posterolateral fusion surgery using a local bone graft. SUMMARY OF BACKGROUND DATA: The iliac crest bone graft technique for lumbar posterolateral fusion surgery is widely used; however, donor site problems such as pain and sensory disturbance have been reported. Local bone has been used for bilateral multisegment fusion surgery; however, outcomes have been poor because of insufficient amounts of local bone used. This study evaluated unilateral and bilateral posterolateral fusion at 3 levels using a local bone graft. METHODS: Sixty-two patients diagnosed with degenerated spondylolisthesis at 3 levels were divided into 2 groups. All underwent decompression and bilateral instrumented posterolateral fusion. However, a unilateral local bone graft was used in 32 patients and bilateral local bone graft was used in 30 patients. The amount of bone grafting, proportion of patients with bone union, duration of bone union, visual analog scale score, Japanese Orthopedic Association score, and Oswestry Disability Index were evaluated before and 2 years after surgery. RESULTS: Visual analog scale score, Japanese Orthopedic Association score, and Oswestry Disability Index were not significantly different between the 2 groups before and after surgery (P > 0.05). The amount of local bone graft used for each segment was significantly less in the bilateral group (P < 0.05). The proportion of patients with rates of bone union and instability were 86% and 9%, respectively, in the unilateral group, but significantly poorer at 60% and 34% in the bilateral group. CONCLUSION: If multisegment fusion (3-level fusion) is performed, bilateral local bone grafting results in a poor rate of bone union because of an insufficiency of local bone. Unilateral bone grafting is recommended because better rates of bone union and stability are achieved.

BACKGROUND: Drehmann sign is a characteristic clinical feature in slipped capital femoral epiphysis (SCFE). The presence of SCFE indicates an anatomic change of the proximal femur, which induces obligatory hip external rotation with hip flexion. In contrast, a cam-type femoro-acetabular impingement (FAI) is well known as sequelae of SCFE. The purpose of this study was to clarify the relationship between Drehmann sign and radiologic FAI. METHODS: We studied 92 hips of 80 SCFE patients who had been treated with in situ fixation. The occurrence rate of Drehmann sign was analyzed according to the degree of remodeling (the Jones classification) and the radiologic α-angle measured in each class at the final follow-up. At a mean 12.2 years after the final follow-up, the patients' present condition was clinically investigated with a questionnaire using a part of the Harris Hip Rating Scale (HHRS). In addition, 3-dimensional computed tomography analysis was performed to clarify the anatomic relationship between the femoral head and the acetabulum during testing for Drehmann sign. RESULTS: Among the 92 hips in the study, 60 were well remodeled (Jones type A), 24 were type B, and 8 were type C, with 6.5 years of mean follow-up. The mean of the modified α-angles for the 3 groups (A, B, and C) were 61.8, 84.7, and 119.4, respectively (P < 0.05); 25%, 75%, and 100% of the hips in the 3 groups, respectively, exhibited Drehmann sign. The set of hips (n = 41) with a positive Drehmann sign had a mean α-angle of 85.6 versus 63.0 degrees for the set of hips (n = 51) with a negative Drehmann sign (P < 0.05). Seven (13.5%) of 52 patients responding to the questionnaire reported hip pain and/or limp in the positive Drehmann sign group, but no patient in the negative sign group complained of either. Three-dimensional computed tomography delineated FAI at 2 different positions during testing for Drehmann sign. CONCLUSIONS: Drehmann sign is highly valuable for clinically evaluating the existence of FAI and for following up with observation or realignment to prevent early osteoarthritis.

OBJECTIVES: The purpose of this study was to clarify the incidence of (CS)-associated osteonecrosis among different underlying diseases and to evaluate the risk factors for steroid-associated osteonecrosis in a prospective MRI study. METHODS: We prospectively used MRI to study 337 eligible underlying disease patients requiring CS therapy and succeeded in examining 1199 joints (hips and knees) in 302 patients with MRI for at least 1 year starting immediately after the onset of CS therapy (1-year follow-up rate of 90%). The underlying diseases included SLE in 687 joints (173 patients) and a variety of other rheumatological disorders in 512 joints (129 patients). RESULTS: The incidence of osteonecrosis was significantly higher in SLE patients than in non-SLE patients (37 vs 21%, P = 0.001). Logistic regression analysis revealed that adolescent and adult patients had a significantly higher risk of osteonecrosis compared with paediatric patients [odds ratio (OR) = 13.2], that high daily CS dosage (>40 mg/day) entailed a significantly higher risk of osteonecrosis compared with the dosage of <40 mg/day (OR = 4.2), that SLE patients had a significantly higher risk of osteonecrosis compared with non-SLE patients (OR = 2.6) and that male patients had a significantly higher risk of osteonecrosis compared with female patients (OR = 1.6). CONCLUSION: These findings suggest that the incidence of CS-associated osteonecrosis varies among different underlying diseases.

PURPOSE: To evaluate articular cartilage degeneration with transverse relaxation time (T2) mapping in systemic lupus erythematosus (SLE) patients with noncollapsed and asymptomatic osteonecrosis of the femoral head associated with corticosteroids. MATERIALS AND METHODS: T2 mapping with a 1.5-T magnetic resonance imaging system was prospectively performed for 28 normal hips from 14 healthy volunteers (control group) and 15 hips from 10 SLE patients that met the inclusion criteria of noncollapsed and asymptomatic osteonecrosis of the femoral head (osteonecrosis group). Exclusion criteria were past experience of pain, trauma, infection, or prior hip joint surgery. Distribution of T2 values of the femoral head cartilage were compared between the control group and the osteonecrosis group with respect to acetabular dysplasia by center-edge angle (CEA). RESULTS: T2 values of the femoral head cartilage were significantly higher in the osteonecrosis group than in the control group (34.4 msec vs. 30.8 msec, P = 0.001). Multiple regression analysis revealed that the osteonecrosis group and decreased CEA was significantly associated with high T2 values (T2 value = 34.6 + 3.6 × [osteonecrosis] - 0.14 × CEA, R(2) = 0.52, P = 0.003). CONCLUSION: Degeneration of articular cartilage was associated with osteonecrosis of the femoral head in SLE patients and acetabular dysplasia.

The aim of this study was to clarify the reproducibility of the Japanese Ministry of Health, Labor and Welfare (JMHLW) type classification for osteonecrosis of the femoral head. We performed inter-observer and intra-observer trials using 40 sets of magnetic resonance imagings, 20 of which were produced by a 0.5 Tesla (T) superconductive unit and the other 20 produced by a 1.5 T unit, in patients with non-collapsed and asymptomatic osteonecrosis of the femoral head (JMHLW stage 1 or 2). The JMHLW type classification (A, B, C1, or C2) was determined from T1-weighted coronal images at the center of the femoral head. Six orthopedic surgeons independently assessed all 40 images twice, with an interval of 4-5 weeks between sessions. Regarding inter-observer reliability, the percent agreement was 85% and weighted kappa was 0.709 for 0.5 T, versus a percent agreement of 82% and weighted kappa of 0.724 for 1.5 T. Regarding intra-observer reliability, the percent agreement was 82% and weighted kappa was 0.780 for 0.5 T versus a percent agreement of 80% and weighted kappa of 0.800 for 1.5 T. Inter-observer and intra-observer reliabilities did not differ significantly between the 0.5 and 1.5 T units. The JMHLW type classification provided high inter-observer and intra-observer reliabilities.

STUDY DESIGN: Gait analysis and immunohistological analysis in a rat model of myofascial inflammation in low back. OBJECTIVE: To investigate gait in a rat model of myofascial inflammation using the CatWalk gait analysis system. SUMMARY OF BACKGROUND DATA: There are few reports examining low back pain behavior in animal models. The CatWalk is a computer-assisted gait analysis system that provides an automated way to assess gait function and this behavior during pain. METHODS: In a myofascial inflammation group, 0.5 mL of 4% paraformaldehyde buffer and 0.5 mL of 5% Fluoro-Gold (FG) buffer were injected into bilateral multifidus muscles of rats. In a control group, FG buffer alone was injected. Five days after surgery, the gait of rats in both groups was investigated using the CatWalk system. In the present study a total of 36 gait parameters were quantified and used to judge pain-related behavior. Bilateral dorsal root ganglia (DRGs) from L1 to L6 levels were resected, and immunostained for calcitonin gene-related peptide (CGRP). RESULTS: In the myofascial inflammation group, the mean duty cycle (duration of paw contact divided by time between consecutive paw contacts) of each paws (front and hind) were significantly higher and mean stride length (the distance between successive placements of the same paw) of each paws were significantly shorter compared with the control group. Furthermore, mean minimum contact intensity of the complete paw and mean contact intensity of each paws in the myofascial inflammation group were significantly higher compared with the control group. The proportion of CGRP-immunoreactive FG-labeled neurons among all FG-labeled DRG neurons in the myofascial inflammation group was significantly higher than the proportion in the control group. CONCLUSION: These results suggest that myofascial inflammation in low back caused the changes to the rat's gait, including long stands, short stride, and strong paw contact.

STUDY DESIGN: Prospective trial. OBJECTIVE: To examine the difference in bone union and clinical results after one-, two-, and three-level instrumented posterolateral fusion surgery using a local bone graft. SUMMARY OF BACKGROUND DATA: The iliac crest bone graft technique for lumbar posterolateral fusion surgery is widely used; however, donor site problems such as pain and sensory disturbance have been reported. Local bone has been used for fusion surgery; however, its reliability as a graft for multiple segments has not been fully reported. METHODS: One hundred twenty-two patients diagnosed with degenerated spondylolisthesis were divided into three groups [spondylolisthesis at 1 level (n = 42), at 2 levels (n = 40), and at 3 levels (n = 40)]. All patients underwent decompression and instrumented posterolateral fusion with a local bone graft. The amount of bone graft, proportion of patients with (rate) and duration of bone union, Visual Analog Scale (VAS) score, Japanese Orthopedic Association Score (JOAS), and Oswestry Disability Index (ODI) were evaluated before and 2 years after therapy. RESULTS: VAS score, JOA score, and ODI were not significantly different among the three groups before and after surgery (P > 0.05). Average amount of local bone graft used for one segment significantly decreased in proportion to the number of fusion levels (P < 0.05). The rate of bone union was 88% in the one-level group, 85% in the two-level group, and 62.5% in the three-level group, which was significantly lower than that in the one- and two-level groups (P < 0.05). CONCLUSION: If one- and two-level posterolateral fusion were performed, the local bone graft technique provides a good and uniform bone union rate; however, for three-level fusion poor results were obtained because of an insufficient amount of local bone.

BACKGROUND: Surgery for lumbar spondylolisthesis is widely performed. However, there have been no reports comparing posterolateral and anterior interbody fusion prospectively. We compared instrumented posterolateral fusion with anterior interbody fusion for L4 spondylolisthesis in a prospective study. METHODS: Forty-six patients diagnosed with L4 degenerated spondylolisthesis were divided into two groups. Twenty-two consecutive patients underwent non-instrumented anterior interbody fusion using an iliac bone graft (ALIF; L4-L5 level), and 24 consecutive patients underwent instrumented posterolateral fusion with local bone (PLF; L4-L5 level). The rates of bone union, visual analog scale (VAS) score, Japanese Orthopedic Association (JOA) score, Oswestry Disability Index (ODI), surgical invasion, and complications were evaluated before and 2 years after surgery. RESULTS: Age, VAS score, JOA score, and ODI were not significantly different between the two groups before surgery (P > 0.05). Success of bone union between the two groups was not significantly different (P > 0.05). Blood loss during surgery was significantly less; however, periods of bed rest and hospital stay were significantly longer in the ALIF group (P < 0.05). Overall patient satisfaction, and low back and leg pain in both groups were significantly improved after surgery; however, low back pain showed greater improvement in the ALIF group compared with the PLF group (P < 0.05). Complications such as donor site pain (4 patients in the ALIF group) and dural tearing (3 patients in the PLF group) were observed. CONCLUSIONS: If single level fusion for L4 spondylolisthesis is performed, both anterior and posterior methods reduce patients' low back and leg pain. Improvement of low back pain was significantly greater after ALIF; however, periods of hospital stay and of bed rest were significantly longer.

In pathologic radicular pain of lumbar spinal stenosis, cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukins (ILs) play a crucial role in the pathogenesis of nerve degeneration and pain. We investigated TNF-α and IL-6 levels in the cerebrospinal fluid (CSF) of patients with radicular pain caused by lumbar spinal stenosis (LSS). A total of 30 LSS patients and 10 age-matched controls were examined. CSF samples were obtained adjacent to the level of stenosis in 30 LSS patients, and at the L4-L5 level in the 10 control patients. TNF-α and IL-6 levels in the samples were analyzed using enzyme-linked immunosorbent assays (ELISA). We compared the amounts of TNF-α and IL-6 with severity of pain (low back and leg pain), walking ability, and severity of stenosis (cross-sectional area of dural space). The concentration of IL-6 was significantly higher in LSS patients than in controls, but TNF-α levels were beneath the limit of detection. There was no correlation between IL-6 levels and severity of pain or walking ability (p > 0.05). However, there was a significant correlation between IL-6 levels and severity of stenosis (p < 0.05). The current study showed that the increased CSF IL-6 levels in LSS patients with radicular pain were not correlated with pain severity; although not proven in this study, the increase in CSF IL-6 concentration could indicate pathological nerve damage or degeneration of lumbar radiculopathy represented by the severity of stenosis.

The iliac crest bone grafting (ICBG) technique for lumbar posterolateral fusion surgery is widely used; however, donor site problems such as pain and sensory disturbance have been reported. Local bone is available for fusion surgery, but its reliability as a graft has not been fully reported. In the current study, we examined single-level instrumented posterolateral fusion with a local bone graft versus an ICBG in a prospective randomized study. Eighty-two patients diagnosed with L4 degenerated spondylolisthesis were divided into two groups at random. Forty-two patients underwent instrumented posterolateral fusion with a local bone graft (L4-L5 level), and 40 patients underwent instrumented posterolateral fusion with an ICBG (L4-L5 level). Rate and duration of bone union, visual analog scale (VAS) score, Japanese orthopedic association score (JOAS), Oswestry Disability Index (ODI), and complications were evaluated before and 2 years after therapy. VAS score, JOAS, and ODI were not significantly different between the two groups before and after surgery (P > 0.05). Rate and average duration of bone union were 90% and 8.5 months in the local bone graft group, and 85% and 7.7 months in the ICBG group, but without significant difference (P > 0.05). Prolonged surgical time and complications such as donor site pain (8 patients) and sensory disturbance (6 patients) were observed in the ICBG group. If single-level posterolateral fusion was performed, local bone graft technique has the same bone union rate compared with ICBG, requires less surgical time, and has fewer complications.

STUDY DESIGN: retrograde neurotracing and immunohistochemistry were used to investigate the effect of the tumor necrosis factor (TNF)-α inhibitor, etanercept, on calcitonin gene-related peptide (CGRP) expression in dorsal root ganglion (DRG) neurons innervating intervertebral discs in rats. OBJECTIVE: to clarify the action of a TNF-α inhibitor on a sensory neuropeptide in DRG neurons innervating intervertebral discs. SUMMARY OF BACKGROUND DATA: degeneration of lumbar intervertebral discs is a cause of low back pain. TNF-α in the intervertebral disc is a major contributor to discogenie pain. Effects of TNF-α inhibition on CGRP expression in DRG neurons were evaluated. METHODS: the neurotracer FluoroGold was applied to the surfaces of L4/5 discs to label their innervating DRG neurons (n = 30). Of 30 rats, 10 were in a nonpunctured disc sham surgery control group, whereas the other 20 were in experimental groups in which intervertebral discs were punctured with a 23-gauge needle. Etanercept or saline was applied into the punctured discs (n = 10 each treatment). After 14 days of surgery, DRGs from L1 to L6 were harvested, sectioned, and immunostained for CGRP. The proportion of FluoroGold-labeled CGRP-immunoreactive DRG neurons was evaluated in all groups. RESULTS: FluoroGold-labeled neurons innervating the L4/5 disc were distributed throughout L1-L6 DRGs in all groups. Of the FluoroGold-labeled neurons, the proportion of CGRP-immunoreactive neurons was 21% ± 4% in the sham surgery control group, 32% ± 7% in the puncture + saline group, and 23% ± 4% in the puncture + etanercept group. The proportion of CGRP-immunoreactive neurons was significantly greater in the puncture + saline group compared with the sham control and puncture + etanercept groups (P < 0.01). CONCLUSION: in this model, CGRP was upregulated in DRG neurons innervating damaged discs. However, direct intradiscal application of etanercept immediately after disc puncture suppressed CGRP expression in DRG neurons innervating injured discs. This finding may further elucidate the mechanism for the effectiveness of etanercept in upregulation of neuropeptide in DRG neurons innervating intervertebral discs.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To examine the utility of 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) to diagnose pyogenic spondylitis in patients showing Modic change. SUMMARY OF BACKGROUND DATA: Vertebral bone marrow infection may appear as Modic type 1 signal on magnetic resonance imaging, so it is difficult to distinguish between common Modic change and infection. In the current study, we aimed to examine the utility of 18F-FDG-PET to diagnose pyogenic spondylitis in patients showing Modic change. METHODS: In a prospective assessment of 312 patients showing low back pain, 18 patients were suspected of having pyogenic vertebral osteomyelitis because of their symptoms, biopsy results, blood analysis, x-ray examination, magnetic resonance imaging, and FDG-PET during a 1-year follow-up. RESULTS: Observers ultimately diagnosed 11 patients with pyogenic spondylitis (group 1 observers). FDG-PET evaluation by 2 radiologists (group 2 observers) showed isotope accumulation in the lumbar spine in 11 patients, and no accumulation in 7 patients. The evaluation by group 1 observers, who did not see the FDG-PET findings, was compared with the evaluation by group 2 observers. No patients were evaluated differently by group 1 and group 2 observers. CONCLUSION: In conclusion, the rate of detecting spondylodiscitis infection was very high if FDG-PET was additionally used. FDG-PET is recommended to distinguish between common Modic change and spinal infection.

BACKGROUND: It has been reported that rat L5/6 lumbar discs are innervated mainly by L2 dorsal root ganglion neurons. We previously reported that L2 spinal nerve infiltration was effective for discogenic low back pain (DLBP) patients, although the diagnosis was based only on the results of physical examination, plain films, and magnetic resonance imaging (MRI). The purpose of the current study was to evaluate L2 spinal nerve block for DLBP patients retrospectively based on MRI findings and surgical results. METHODS: A total of 62 patients with only LBP and no accompanying radicular pain were investigated. Patients had only one level of disc degeneration on MRI. When pain was provoked during discography, we performed surgery at the next stage (40 patients). In all, 22 patients were excluded owing to negative discography results. Of the 40 patients, we evaluated 25 strictly selected patients suffering from DLBP. DLBP was diagnosed when the patient experienced pain relief at least 2 years after anterior lumbar interbody fusion. Fifteen patients who did not show pain relief after surgery were used for the non-DLBP group. L2 spinal nerve infiltration using 1.5 ml of lidocaine was performed in all 40 patients before surgery. The visual analogue scale (VAS) score after L2 spinal nerve infiltration was recorded, and an association of L2 spinal nerve infiltration and DLBP was explored. RESULTS: Low back pain scores assessed using the VAS score, the Japanese Orthopedic Association score, and the Oswestry Disability Index score in the two groups were not significantly different. L 2 spinal nerve infiltration was effective for 27 patients but not effective for 13 patients; the VAS score after 15 min and 2 h improved in the DLBP group compared with that of the non-DLBP group (P < 0. 05). L2 spinal nerve infiltration was more effective in DLBP patients (21 patients, 84%) than in the non-DLBP group (6 patients, 40%) (P < 0.05). CONCLUSIONS: In the current study, L2 spinal nerve infiltration was effective in 84% of selected DLBP patients and is thought to be a useful tool for diagnosing DLBP. However, we should take into consideration that the L2 spinal nerve infiltration was effective in 40% of non-DLBP patients as well.

単純性股関節炎の疫学的傾向を明らかにすることを目的に、股関節痛の発症した日を調査した。対象は2002年4月〜2009年3月の間に千葉県こども病院(千葉県)、国立成育医療センター(東京都)、埼玉県立小児医療センター(埼玉県)を受診した200例211股で、平均年齢は6.3±2.8歳(0.8〜17歳)であった。各施設の発生数が2〜6ヵ月間にわたり同時に増加する時期が認められたが、全期間を通してみると必ずしも一致していなかった。月別では2月に少ない傾向が認められたが、一定の季節性は認められなかった。本研究の結果、明らかな疫学的傾向は認められなかったが、本疾患はある期間に集中して発症する傾向があった。複数病原体による感染症である無菌性髄膜炎と年間の発生件数を比較すると、極めて類似した変動を示しており、共通の病原体の存在が示唆された。(著者抄録)

先天性股関節脱臼後遺残変形に対して当科で10歳代に手術治療を行い2年以上経過観察した13例14股の臨床成績を調査した。手術時年齢は10歳から17歳、平均13.8歳であった。術式は、タナ形成術が8股(2股はWagner法、2股は大腿骨転子部内反骨切り術、1股は大転子下降術を合併)、寛骨臼回転骨切り術が4股、Pemberton骨切り術と大腿骨内反骨切り術の合併手術が2股であった。大腿骨頭壊死は12股86%で術前からみられた。術後経過観察期間は平均6.4年、最終診察時年齢は平均20.2歳であった。Severin分類class I、IIを成績良好とすると11股79%がこれに該当した。しかし9股64%で跛行、疼痛などの症状が断続的または持続的にみられていた。どの術式にも課題が残されていたが、姑息的手術と考えられるタナ形成術は意外に好結果をもたらしていた。(著者抄録)

Pathomechanisms of injured-nerve pain have not been fully elucidated. Radicular pain and chronic constriction injury models have been established; however, producing these models is complicated. A sciatic nerve-pinch injury is easy to produce but the reliability of this model for evaluating pain behavior has not been examined. The current study evaluated pain-related behavior and change in pain markers in the dorsal root ganglion (DRG) of rats in a simple, sciatic nerve-pinch injury model. In the model, the sciatic nerve was pinched for 2 s using forceps (n = 20), but not injured in sham-operated animals (n = 20). Mechanical and thermal hyperalgesia were measured every second day for 2 weeks using von Frey filaments and a Hargreaves device. Calcitonin gene-related peptide (CGRP), activating transcription factor-3 (ATF-3), phosphorylated p38 mitogen activated protein (Map) kinase (p-p38), and nuclear factor-kappa B (NF-κB; p65) expression in L5 DRGs were examined at 4 and 7 days after surgery using immunohistochemistry. The proportion of neurons immunoreactive for these markers was compared between the two groups. Mechanical (during 8 days) and thermal hyperalgesia (during 6 days) were found in the pinch group rats, but not in the sham-operated animals (p < 0.05); however, hyperalgesia was not significant from days 10 to 14. CGRP, ATF-3, p-p38, and NF-κB expression in L5 DRGs was upregulated in the nerve-injured rats compared with the sham-operated rats (p < 0.01). Our results indicate that a simple sciatic nerve pinch produced pain-related behavior. Upregulation of the pain-marker expression in the nerve-injury model suggested it could be used as a model of pain. However, it was not considered as suitable for long-term studies.

The relationship of Modic change to pain and inflammation remains to be unclear. Recently, some authors have reported that Modic type 1 signals are closely related to infection. However, if the patients do not have severe back pain, fever, or an abnormal blood profile, it is difficult to distinguish between common Modic change and infection. The purpose of this study was to examine the prevalence of pyogenic spondylitis in patients who showed Modic type 1 change without other signs of infection. Seventy-one patients with Modic type 1 change were evaluated (average age 55, 32 males and 39 females). X-ray and magnetic resonance imaging (MRI) were performed to investigate low-back pain and leg pain. Body temperature was measured and blood analysis (including white blood cell count and level of C-reactive protein) was conducted for all patents. All 71 patients with Modic type 1 change, but without other signs of infection were followed for 2 years. Low-back pain, X-ray, and blood analyses were performed every 3 months; and MRI was performed every year. Severe low-back pain or abnormal signs developed in four patients during the follow-up. Pyogenic spondylitis was diagnosed in three patients by symptoms, blood results, and imaging, and confirmed by biopsy. Two of the three patients were diabetic. A total of 4.2% of patients with Modic type 1 change, but without other signs of infection were diagnosed as having pyogenic spondylitis during the 2-year follow-up, therefore, it is important to consider this before treating Modic type 1 change.

The number of patients showing lumbar degenerative scoliosis, including disc wedging, has increased, and examination of the mechanism of spinal nerve compression due to lateral and rotational mobility of the lumbar spine is necessary. Thirty-two patients with L4-L5 disc wedging but without antero- or retrospondylolisthesis and ten age-matched controls were examined. The angle of disc wedging and change in the angle between left and right bending were evaluated by anterior-posterior X-ray images of patients while they were in a standing position. The degree of disc degeneration and existence of vacuum phenomena were evaluated at the L4-L5 discs. Rotational mobility between maximal right and left rotation was examined by computed tomography (CT). Rotational mobility was measured using the spinal transverse processes of L4 and L5. The relationship between these factors was statistically evaluated using multivariate analysis and Spearman's correlation test. There was a significant increase in the average rotational mobility of the L4-L5 disc-wedging group. In the L4-L5 disc-wedging group, the increased angle of disc wedging and change in the angle between left and right bending correlated with increased rotational mobility. The degree of disc degeneration did not affect rotational mobility. However, existence of vacuum phenomena increased the rotational mobility of the L4-L5 disc-wedging group. This is the first study to evaluate the rotational hypermobility of L4-L5 disc wedging in patients without antero- or retrospondylolisthesis using kinematic CT. Increases in the wedging angle and abnormal instability of lateral bending correlated with increased rotational mobility. For surgical planning of degenerative L4-L5 disc wedging, it is important to consider rotational hypermobility using kinematic CT or X-ray imaging findings of lateral bending.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To examine the relationship between low back pain after discectomy for disc herniation and Modic type 1 change. SUMMARY OF BACKGROUND DATA: Lumbar vertebral bone marrow change is divided into Modic types. Some reports indicate that Modic type 1 is related to low back pain, but the reliability of this assertion is unclear. The current study examines changes in low back pain in patients with lumbar disc herniation and Modic type 1 change after lumbar discectomy without fusion surgery. METHODS: Forty-five patients with lumbar disc herniation showing normal or Modic type 1 signals in their bone marrow were selected (mean age 35 years). All patients suffered low back and leg pain because of lumbar disc herniation, and underwent a discectomy without fusion. We evaluated change in low back pain [Visual analogue scale (VAS) score, Japanese Orthopedic Association score (JOAS), and Oswestry Disability Index (ODI)] before, 12 and 24 months after surgery. RESULTS: Twenty-three patients showed Modic type 1 signals and 22 patients showed normal intensity before surgery. VAS score, JOAS, and ODI were not significantly different between the normal and Modic type 1 groups. VAS score, JOAS, and ODI improved after surgery in both groups (P>0.05). Low back pain after surgery evaluated from the 3 scores was not significantly different in the 2 groups 12 or 24 months after surgery (P>0.05). CONCLUSION: Discectomy improved low back pain in patients suffering from lumbar disc herniation. Patients with or without Modic type 1 change showed a similar improvement of low back pain score. Low back pain in patients with disc herniation appears to mainly originate from disc or nerve root compression, and decompression surgery without fusion is an option for these patients, even those with Modic type 1 changes.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To examine the change of Modic Type 1 to Type 2 after posterolateral fusion surgery. SUMMARY OF BACKGROUND DATA: Lumbar vertebral bone marrow change is divided into Modic types. Magnetic resonance imaging reveals Modic Type 1 and 2 signals. Some reports indicate that with time, Type 1 signals (intervertebral instability) change to Type 2 (restabilization), but the reliability of this assertion is unclear. The current study examines the change of Modic Type 1 signals to Type 2 after posterolateral fusion surgery. METHODS: Patients with Modic Type 1 and 2 signals were selected (mean age, 65 years). All patients suffered low back pain and leg pain due to lumbar spinal canal stenosis, and underwent decompression and posterolateral fusion surgery. We evaluated change in Modic signal and severity of low back pain (Visual analogue scale score, Japanese Orthopedic Association score, and Oswestry Disability Index before and 24 months after surgery. RESULTS: Of 21 patients with Modic Type 1 signals before surgery, 2 cases changed to normal bone marrow, 9 to Type 2, and 12 remained Type 1. Of 12 patients with Type 2 signals, none changed to Type 1, 2 changed to normal bone marrow, and 10 remained Type 2. Visual analogue scale score, Japanese Orthopedic Association score, and Oswestry Disability Index improved after surgery; however, low back pain was not significantly associated with signal change after surgery (P > 0.05). CONCLUSION: In the current study, Modic Type 1 signals changed to Type 2; however, Type 2 did not change to Type 1, suggesting that Type 2 signals indicate a stabilized stage. For Modic Type 1 and 2 signals, there were changes to normal bone marrow signals in 4 cases. Therefore, degenerated bone marrow may be able to regenerate after surgical stabilization. We did not show a significant difference between low back pain and signal type.

BACKGROUND: Clinically, the origin of low back pain is unknown. The pain may originate from the lumbar muscles directly, or it may be referred pain from the spine. Dorsal root ganglion (DRG) neurons with dichotomizing axons have been reported in several species and are thought to be related to referred pain. However, these neurons, which have dichotomizing axons to the lumbar facet joints and to the lumbar muscle, have not been fully investigated. METHODS: Two neurotracers - 1,1'-dioctadecyl-3,3,3',3'- tetramethyl-indocarbocyanine perchlorate (DiI) and fluorogold (FG) - were used in the present double-labeling study. DiI crystals were placed in the right L5/6 facet joint, and FG was applied to right multifidus muscles at the L5 level in 10 rats. Two weeks later, bilateral DRGs from L1 through L6 were harvested, sectioned, and observed under a fluorescence microscope. RESULTS: DiI-labeled DRG neurons innervating the L5/6 facet joint (5.17% of the total DRG neurons) were distributed from L1 to L6. FG-labeled DRG neurons innervating the lower back muscle (15.9% of the total) were also distributed from L1 to L6. Double-labeled DRG neurons were found from L1 to L6. The ratio of total double-labeled/total DiI-labeled DRG neurons was 17% and that of total double-labeled/total FG-labeled DRG neurons was 7%. Approximately 17% of all DRG neurons innervating the facet joints had other axons that extended to the lower back muscle. CONCLUSIONS: This finding provides a possible neuroanatomical explanation for referred low back muscle pain from the lower facet joints.

BACKGROUND: Recent studies have revealed that the low-affinity nerve growth factor receptor, p75 neurotrophin receptor (p75NTR), is important in inflammatory pain. Moreover, p75NTR immunoreactive sensory nerve and dorsal root ganglion (DRG) neurons have been found to innervate lumbar intervertebral discs. The purpose of the current study was to investigate the effect of p75NTR saporin, a toxin used to destroy p75NTR, on calcitonin gene-related peptide (CGRP), an inflammatory neuropeptide associated with pain, in DRG neurons innervating punctured intervertebral discs in rats. METHODS: The neurotracer fluorogold (FG) was applied to the surfaces of L5/6 discs to label their innervating DRG neurons (n = 30). Of 30 rats, 10 were in a nonpunctured disc sham surgery control group (nonpuncture group), and the other 20 were in experimental groups in which intervertebral discs were punctured with a 23-gauge needle. p75NTR saporin was applied to the discs of 10 rats (puncture + p75NTR saporin group) and the other 10 received the same volume of saline (puncture + saline group). At 14 days after surgery, DRGs from L1 to L6 were harvested, sectioned, and immunostained for CGRP, and the proportions of CGRP-immunoreactive DRG neurons was evaluated. RESULTS: Of the FG-labeled neurons innervating the L5/6 disc, the proportion of CGRP-immunoreactive neurons was 32% +/- 6% (mean +/- SE) in the nonpuncture group, 47.2% +/- 8% in the puncture + saline group, and 34.6% +/- 9% in the puncture + p75NTR saporin group. The proportion of CGRP-immunoreactive neurons was significantly greater in the puncture + saline group compared with the nonpuncture and puncture + p75NTR saporin groups (P < 0.01). CONCLUSIONS: Half of the DRG neurons innervating the discs were positive for CGRP in the puncture + saline group. CGRP is important for mediating inflammatory and nerve-injured pain and may be important in discogenic pain. However, p75NTR saporin suppressed CGRP expression in DRG neurons. Therefore, p75NTR may be an important receptor for mediating discogenic pain via CGRP expression.

Elderly postmenopausal women who have osteoporosis sometimes experience low back pain, however, the relationship between low back pain and osteoporosis in the absence of vertebral fractures remains unclear. We examined the relationship between bone mineral density (BMD), bone resorption and low back pain in elderly female patients who did not have osteoporotic vertebral fractures. The average BMD was 0.675 g/cm(2) when assessed by dual-energy X-ray absorptiometry (DEXA). Patients were excluded from the study if they had vertebral fractures revealed by radiography, CT scans or MRI. Bisphosphonate (risedronate) was administered for 4 months. The visual analogue scale (VAS) pain score, Roland Morris Disability Questionnaire (RDQ), Short Form-36 (SF-36) questionnaire, BMD and N-terminal telopeptide of type I collagen (NTx; a marker for bone resorption) were examined before and after treatment. DEXA did not increase significantly, but serum and urinary NTx were decreased (-51.4% and -62.0%, respectively) after 4 months of risedronate treatment (p<0.01). The assessment was repeated using the VAS score, RDQ and SF-36, which revealed an improvement after risedronate treatment (p<0.01). A decrease in serum and urinary NTx was associated with improvement of low back pain, suggesting that despite the absence of vertebral fractures, bone resorption due to osteoporosis may cause low back pain.

OBJECTIVE: To clarify whether age at the time of the initial administration of corticosteroids is a risk factor for corticosteroid-associated osteonecrosis in children with systemic lupus erythematosus (SLE), using magnetic resonance imaging (MRI). METHODS: From 1986 to 2007, MRI was used to prospectively study 676 joints, including 72 joints (36 hips and 36 knees) in 18 pediatric patients with SLE (<15 years old), 100 joints (50 hips and 50 knees) in 25 adolescent patients with SLE (15-20 years old), and 504 joints (252 hips and 252 knees) in 126 adult patients with SLE (>20 years old), beginning just after corticosteroid administration, for at least 1 year. The followup rate was 100%. RESULTS: In pediatric patients, osteonecrosis developed in 4 joints (6%; all hips). In adolescent patients, osteonecrosis developed in 49 joints (49%; 18 hips and 31 knees). In adult patients, osteonecrosis developed in 207 joints (41%; 95 hips and 112 knees). The rate of osteonecrosis was significantly lower in pediatric patients than in adolescent or adult patients (P = 0.0001). Logistic regression analysis revealed that adolescent and adult patients had a significantly higher risk for osteonecrosis compared with pediatric patients, with an odds ratio of 10.3 (P < 0.0001). The youngest patients with osteonecrosis in the hip and knee were 14.9 years old and 15.5 years old, respectively. Osteonecrosis did not develop in patients younger than age 14 years. CONCLUSION: Our results suggest that age at the time of the initial administration of corticosteroids is associated with osteonecrosis in pediatric patients with SLE.

BACKGROUND: Hinge abduction is widely accepted as a poor prognostic factor in Legg-Calvé-Perthes disease (LCPD), whereas the exact definition of hinge abduction remains ill defined. The purpose of this diagnostic study was to refine the definition of hinge abduction in LCPD using conventional hip arthrography under general anesthesia. METHODS: Among 350 hips in 332 LCPD patients, we reviewed 92 hips in 90 patients (75 boys and 15 girls) who consecutively underwent arthrography under general anesthesia because of an expected poor prognosis. The mean age at LCPD onset was 8.2 years (range, 4-13 years). With respect to lateral pillar classification, 25 hips were classified as group B, 27 as B/C border, and 40 as C. Subluxation (>or=3-mm difference from unaffected side) was present in 81 (88%) of the 92 hips. The modified Waldenström classification was used for evaluating the radiographic stage of disease at the time of arthrography: 80 hips were classified as fragmentation stage and 12 as reossification stage. Hinge abduction was defined as an increased subluxation index in maximum abduction and/or a positive impingement sign. RESULTS: Under this definition, 11% (10 hips) of the study group had hinge abduction. The range of abduction under general anesthesia (40 degrees) was significantly greater than in the awake condition (24 degrees, P < 0.0001). CONCLUSIONS: The subluxation index and the impingement sign proved to be reliable indicators for diagnosing hinge abduction. Conventional arthrography remains useful. General anesthesia provided an analgesic effect and muscle relaxation. LEVEL OF EVIDENCE: Level II (diagnostic study, development of diagnostic criteria on the basis of consecutive patients).

PURPOSE: There is not always a good outcome after a femoral varus osteotomy (FVO) in those with Legg-Calvé-Perthes disease (LCPD), even when the severity warrants surgical treatment. The purpose of this study was to find arthrographic indicators for decision making regarding the likely surgical outcome of a FVO. METHODS: We used an image of an abduction position during preoperative arthrography under general anesthesia that simulated the post-operative relationship between the femoral head and the acetabulum. In the image, we defined two indicators of how deeply the deformed epiphysis was contained within the acetabulum: an acetabular head index in abduction and an epiphyseal slip-in index. Finding the contact point between the top of epiphysis and acetabulum was the key for the epiphyseal slip-in index measurement. In 37 patients (38 hips) who underwent FVOs based on our inclusion criteria, these two indices were measured retrospectively and were analyzed for a correlation with surgical outcome. Surgical outcome was evaluated using a combination of three factors: sphericity of the femoral head (Stulberg's classification), acetabular cover (acetabular head index), and the slope of acetabular roof. RESULTS: The outcome was acceptable in 20 hips (52.6%) and unacceptable in18 hips (47.4%). There was a statistically significance difference in epiphyseal slip-in index between the acceptable group (21.9 +/- 2.8%) and the unacceptable group (15.0 +/- 4.4%) (P < 0.0001). An index of 20% or more determined a safe zone for predicting an acceptable outcome with 80% sensitivity, 89% specificity, and a 7.2 likelihood ratio. However, the acetabular head index in abduction showed no such statistical significance. CONCLUSIONS: In this study, we found that the epiphyseal slip-in index was a reliable indicator for predicting the effectiveness of a FVO. It is worth measuring this index when a surgeon is considering a FVO for a patient with severe LCPD. (Level of Evidence Level III.).