Takashi Saisu

Second application of low-energy shock waves has a cumulative effect on free nerve endings.

Some physicians recommend treating tendinopathies with multiple sessions of shock waves. Some evidence, however, suggests shock wave application can induce nerve fiber degeneration. We questioned whether repeated shock wave application provides a cumulative effect on nerve fibers compared with the effect of one application. One thousand shock wave impulses of an energy flux density of 0.08 mJ/mm2 were applied to the foot pad of 32 rats. After 14 days, 16 rats received a second application. The foot pads were resected on Days 7, 14, 28, and 42. Sections were processed immunohistochemically using antibodies for sensory nerve. We compared the number of epidermal nerve fibers in rats that received one application of shock waves with the fibers in rats that received two applications. During the first 4 weeks, there was nearly complete degeneration of epidermal nerve fibers in both groups. By the end of 6 weeks, reinnervation of the epidermis began in the single-treatment group. Reinnervation occurred slower in the repeated-treatment group. These data show that a second application has a cumulative effect on nerve fibers. Our data suggest multiple applications of low-energy shock waves might a provide longer-lasting antinociceptive effect.

Age at time of corticosteroid administration is a risk factor for osteonecrosis in pediatric patients with systemic lupus erythematosus: A prospective magnetic resonance imaging study

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.

Extracorporeal shockwaves induce the expression of ATF3 and GAP-43 in rat dorsal root ganglion neurons.

Although extracorporeal shockwave has been applied in the treatment of various diseases, the biological basis for its analgesic effect remains unclear. Therefore, we investigated the dorsal root ganglion neurons of rats following shockwave exposure to the footpad to elucidate its effect on the peripheral nervous system. We used activating transcription factor 3 (ATF3) and growth-associated phosphoprotein (GAP-43) as markers for nerve injury and axonal regeneration, respectively. The average number of neurons immunoreactive for ATF3 increased significantly in the treated rats at all experimental time points, with 78.3% of those neurons also exhibiting immunoreactivity for GAP-43. Shockwave exposure induced injury of the sensory nerve fibers within the exposed area. This phenomenon may be linked to the desensitization of the exposure area, not the cause of pain, considering clinical research with a particular absence of painful adverse effect. Subsequent active axonal regeneration may account for the reinnervation of exposed area and the amelioration of the desensitization.

A proposed prognostic formula for Perthes' disease

We retrospectively reviewed 145 patients with unilateral Perthes’ disease and compared a quantitative analysis of early radiographic signs with a predicted prognosis at long-term followup. The average age of the patients at followup was 18.7 years (range, 16.2-27.5 years). We used the age at onset and three radiographic factors as independent variables for multiple regression analysis. The final radiographic results were based on a modified Stulberg’s classification as the dependent variable. Fifty patients (35%) had a good outcome, 33 patients (23%) had a fair outcome, and 62 patients (42%) had a poor outcome. The most reliable formula in the stepwise multiple regression analysis was calculated as: y = −0.697 + 0.418 (age score) + 0.860 (involvement score) + 0.248 (subluxation score). The radiographic stage at first visit had no influence on the final results. Multifactorial assessment by combination of age at onset and two radiographic factors (epiphyseal involvement and subluxation) was the most reliable for predicting the prognosis. A score of 1.5 points or less predicted a good prognosis and a score of 2.6 or more indicated a poor prognosis. Level of Evidence: Prognostic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Humeral Shortening and Inferior Subluxation as Sequelae of Septic Arthritis of the Shoulder in Neonates and Infants

BACKGROUND Although humeral shortening as a sequel of septic arthritis of the shoulder in infants has been reported in previous studies, functional disorders of the shoulder resulting from humeral shortening have not yet been clarified. In this study, we retrospectively investigated the long-term outcome of septic arthritis of the shoulder in neonates and infants and examined the relationship between growth disturbance of the humerus and decreased range of motion with respect to glenohumeral joint laxity. METHODS We reviewed the cases of fifteen patients (sixteen shoulders) with an age of a few days to 2.6 years at the onset of the disease who were followed from 5.0 to 17.9 years. We noted the initial treatment method and evaluated humeral length and shoulder function at the time of the final follow-up. For the final treatment results, we classified the shoulders with normal findings on radiographs as Grade I, those with humeral head deformity as Grade II, and those with humeral head deformity with inferior subluxation as Grade III. RESULTS Primary treatment included arthrotomy in ten shoulders. The delay between the onset of the disease and surgery ranged from three to twenty-six days. At the time of the final follow-up, the results were Grade I in five shoulders, Grade II in six shoulders, and Grade III in five shoulders. The mean humeral shortening was 0.1 cm for Grade-I shoulders, 0.9 cm for Grade-II shoulders, and 7.3 cm for Grade-III shoulders. All Grade-III shoulders had >or=3 cm of shortening, and four of the five Grade-III shoulders showed limitation of elevation (abduction of <130 degrees ). None of the Grade-III shoulders had undergone arthrotomy within ten days after the onset of the disease. CONCLUSIONS Inferior subluxation of the humeral head related to shoulder dysfunction resulting from early childhood septic arthritis accompanied humeral shortening of >or=3 cm and was only observed in patients who did not undergo arthrotomy of the shoulder within ten days after the onset of the infection.

Degeneration and Recovery of the Neuromuscular Junction after Application of Extracorporeal Shock Wave Therapy

It is known that free nerve endings are degenerated after application of shock waves. We therefore hypothesized that the application of shock waves to muscle induces dysfunction of neuromuscular transmission at neuromuscular junctions. We investigated changes in neuromuscular transmission in response to shock wave application. Sprague–Dawley rats were used in this study. Two thousand shock waves at an energy flux density of 0.18 mJ/mm2 were applied to their right calf muscles. Neuromuscular junctions of gastrocnemius muscles were evaluated using rhodamine–α‐bungarotoxin on the day of treatment (n = 5). Amplitude and latency of compound muscle action potentials were measured on the day of treatment and 1, 2, 4, 6, and 8 weeks after treatment (n = 10, each group). Degenerated acetylcholine receptors existed in all treated muscles. Although the action potential amplitude on the treated side was significantly less than on the control side from the day of treatment (25.1 ± 7.8 vs. 34.5 ± 9.1, p = 0.012) to 6 weeks (27.9 ± 7.2 vs. 34.5 ± 7.2, p = 0.037), there was no significant difference at 8 weeks. There was no significant difference in transmission latency between the groups. The application of shock waves to muscle induced a transient dysfunction of nerve conduction at neuromuscular junctions.

Preoperative assessment for intertrochanteric femoral osteotomies in severe chronic slipped capital femoral epiphysis using computed tomography.

We propose here to focus on preoperative assessment for intertrochanteric femoral osteotomies in severe slipped capital femoral epiphysis (SCFE) using computed tomography. This intertrochanteric osteotomy was preoperatively customized for each chronic SCFE patient treated, and has been performed on 22 patients with an average posterior slip angle of 55°. The osteotomy is planned with images from computed tomography as follows. The angle between a provisional axis on one image and the axis of the lateral aspect of the femur on the other image is defined as &agr;. When the &agr; angle varies from 20 to 30°, a simple flexion osteotomy is selected for correction along the axis of the lateral femur; when the &agr; angle is more than 30°, a flexion osteotomy along with some valgus correction should be considered; when the &agr; angle is less than 20°, varus correction should be added. The postoperative posterior slip angle, head-shaft angle (P<0.05) and epiphyseal height ratio (P<0.005) in the group using our method were superior to the Southwick group. Postoperative hip motion was nearly the same as the unaffected side. The average leg length discrepancy was 0.9 cm (range, from 0 to 2.0 cm). Reduced blood loss (P<0.001) and shorter operation time (P<0.001) were also noted, compared with the Southwick group. We concluded that the intertrochanteric femoral osteotomy based on this strategy minimizes the surgical complexity, resulting in a more anatomic reduction of the capital femoral epiphysis.

Hip arthrography under general anesthesia to refine the definition of hinge abduction in Legg-Calvé-Perthes disease.

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 (≥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).

Effects of extracorporeal shock waves on immature rabbit femurs.

We hypothesized that extracorporeal shock waves induce overgrowth and local increases in bone mineral content (BMC) in immature long bones. Immature male rabbits (n=14; 9 weeks old) were randomized equally between group I, which received 1000 100 MPa shock waves on the femoral shaft and group II, which received 5000. Unexposed femurs were used as controls. No fractures occurred in group I; three occurred in group II. Six weeks after exposure, the length and width were significantly larger (1.0 and 14.9%, respectively), and the BMC was significantly higher (22.8%) than those of control femurs in group I. These results of differences in width and BMC might be clinically useful.

Athletic ability of school-age children after satisfactory treatment of congenital clubfoot.

Background: This is the first study to objectively assess the athletic ability of school-age congenital clubfoot patients. Methods: Forty-six feet of 30 patients (18 boys, 12 girls) were evaluated in this study. Nine patients were treated conservatively, 8 patients underwent percutaneous tenotomy of the Achilles tendon, and 13 patients were treated with extensive soft-tissue release. The mean age at the investigation was 9.2±1.9 years, and the mean follow-up period was 8.3±2.9 years. Athletic ability was evaluated by calculating Z-scores for the patients’ scores in 5 physical fitness tests routinely performed nationwide at elementary schools: 50-meter run; standing long jump; repetition side steps; 20-meter shuttle run; and sit-ups. The Z-scores were calculated based on data published as the nationwide standards. Results: Of the 148 scores recorded for the 5 tests for the 30 clubfoot patients, 143 scores (96.6%) were higher than the −2 SD value. The mean Z-scores were as follows: −0.32 for 50-meter run; −0.16 for standing long jump; −0.24 for 20-meter shuttle run; 0.22 for repetition side steps; and 0.06 for sit-ups. None of the events showed any significant differences among the three treatment groups. Conclusions: Congenital clubfoot with satisfactory treatment did not significantly impair the athletic performance. Level of Evidence: Prognostic level III.