Epidemiology of paediatric elbow fractures: a retrospective multi-centre study of 488 fractures.

PURPOSE: Elbow fractures are common in children and occur during daily activities. The aim of this study is to evaluate the epidemiology of paediatric elbow fractures over a two-year period in Okinawa, a southern subtropical island in Japan. METHODS: This was a retrospective study of 488 elbow fractures in children younger than 15 years old treated at 11 hospitals in Okinawa. Data included age, gender, calendar month, type of fracture, operation rate, mechanism of injury, and aetiology. RESULTS: The most frequent age was 6 years old, with 47.5% of all elbow fractures occurring in an age range from 6 to 10 years old. The fracture rate for boys was 1.6 times higher than that for girls. The incidence was the highest in May (56 fractures) and the lowest in August (25 fractures). Supracondylar fractures were the most common type (44%), followed by lateral condyle fractures (22%); 45% of all fractures were treated operatively. Medial epicondyle fractures had the highest rate of operative treatment (91%). In the 6 to 10-year-old group, 19% of all fractures occurred while skateboarding or caster-boarding, the most frequent aetiology. CONCLUSIONS: Supracondylar fractures are the most common fracture type in 4 to 7-year-old boys. In the 6 to 10-year-old group, skateboarding and caster-boarding are the most frequent and increasing cause of elbow fractures. Therefore, some preventive measures are needed. LEVEL OF EVIDENCE: Level IV, case series.

Efficiency of dual-cured resin cement polymerization induced by high-intensity LED curing units through ceramic material.

OBJECTIVE: This study aimed to evaluate the ability of high-intensity light-emitting diode (LED) and other curing units to cure dual-cured resin cement through ceramic material. METHODS: A halogen curing unit (Jetlite 3000, Morita), a second-generation LED curing unit (Demi, Kerr), and two high-intensity LED curing units (PenCure 2000, Morita; Valo, Ultradent) were tested. Feldspathic ceramic plates (VITABLOCS Mark II, A3; Vita Zahnfabrik) with thicknesses of 1.0, 2.0, and 3.0 mm were prepared. Dual-cured resin cement samples (Clearfil Esthetic Cement, Kuraray Noritake Dental) were irradiated directly or through one of the ceramic plates for different periods (5, 10, 15, or 20 seconds for the high-intensity LED units and 20, 40, 60, or 80 seconds for the others). The Knoop hardness test was used to determine the level of photopolymerization that had been induced in the resin cement. Data were analyzed by one-way analysis of variance and Dunnett's post-hoc test to identify test-control (maximum irradiation without a ceramic plate) differences for each curing unit (p<0.05). RESULTS: For all curing units, the curing conditions had a statistically significant effect on the Knoop hardness numbers (KHNs) of the irradiated cement samples (p<0.001). In general, the KHN decreased with increasing plate thickness and increased as the irradiation period was extended. Jetlite 3000 achieved control-level KHN values only when the plate thickness was 1.0 mm. At a plate thickness ≥2.0 mm, the LED units (except for PenCure 2000 at 3.0 mm) were able to achieve control-level KHN values when the irradiation time was extended. At a plate thickness of 3.0 mm, irradiation for 20 seconds with the Valo or for 80 seconds with the Demi were the only methods that produced KHN values equivalent to those produced by direct irradiation. CONCLUSION: Regardless of the type of curing unit used, indirect irradiation of dual-cured resin cement through a ceramic plate resulted in decreased KHN values compared with direct irradiation. When the irradiation period was extended, only the LED units were able to achieve similar KHN values to those observed under direct irradiation in the presence of plates ≥2.0-mm thick. High-intensity LED units require a shorter irradiation period than halogen and second-generation LED curing units to obtain KHN values similar to those observed during direct irradiation.

Growth kinetics and integrin expression of fibroblasts infiltrating devitalised patellar tendons are different from those of intrinsic fibroblasts.

We compared the biological characteristics of extrinsic fibroblasts infiltrating the patellar tendon with those of normal, intrinsic fibroblasts in the normal tendon in vitro. Infiltrative fibroblasts were isolated from the patellar tendons of rabbits six weeks after an in situ freeze-thaw treatment which killed the intrinsic fibroblasts. These intrinsic cells were also isolated from the patellar tendons of rabbits which had not been so treated. Proliferation and invasive migration into the patellar tendon was significantly slower for infiltrative fibroblasts than for normal tendon fibroblasts. Flow-cytometric analysis indicated that expression of alpha5beta1 integrin at the cell surface was significantly lower in infiltrative fibroblasts than in normal tendon fibroblasts. The findings suggest that cellular proliferation and invasive migration of fibroblasts into the patellar tendon after necrosis are inferior to those of the normal fibroblasts. The inferior intrinsic properties of infiltrative fibroblasts may contribute to a slow remodelling process in the grafted tendon after ligament reconstruction.

Search for active endogenous retroviruses: identification and characterization of a HERV-E gene that is expressed in the pancreas and thyroid.

To elucidate possible physiological functions of human endogenous retroviruses (HERVs) and their role in the pathogenesis of human diseases, we have developed a strategy to identify transcriptionally active HERV genes. By this approach, we have identified and isolated an active HERV-E gene that was mapped to 17q11. Although the gene was predicted to produce no intact viral particles due to the presence of stop codons, long open reading frames were retained in each gag and pol region. Northern blot analyses revealed in the pancreas (and thyroid) two major transcripts, 3.3 and 4.1 kb in size, associated with 500- to 600-nucleotide-longer minor bands. Preferential expression in pancreas and thyroid gland tissues may suggest a role for this gene in physiological functions common to these tissues.

Preserved sympathetic skin response at the distal phalanx in patients with carpal tunnel syndrome.

OBJECTIVE: To assess the viability of sympathetic sudomotor fibers in carpal tunnel syndrome (CTS). METHODS: We recorded sympathetic skin response (SSR) with a multichannel recording system. Forty-four patients with CTS (51 hands), 7 patients (7 hands) with asymptomatic median mononeuropathy at the wrist (MMW), and 20 normal subjects (20 hands) were studied. We classified the patients into 4 grades of increasing severity. RESULTS: In the hands of normal subjects, SSR was evoked easily at all recorded sites. SSR at the wrist in patients with asymptomatic MMW decreased in amplitude. SSR was markedly distorted at the wrist in severe grades of CTS. The SSR amplitude ratio (wrist/distal phalanx) decreased significantly with more severe grade (rh=-0.4; P<0.05), but the sensitivity was lower than that of other electrodiagnostic criteria. A patient with persistent allodynia at the wrist after surgery showed the slight recovery of SSR amplitude ratio; the other two patients without allodynia showed substantial recovery of SSR amplitude ratio within 24 weeks after surgery. CONCLUSION: SSR amplitude ratio is a poor indicator of CTS diagnosis, but may be useful in assessing the viability of sympathetic sudomotor fibers and may assist in evaluating the response to surgery.

Mobilization of a congenital proximal radioulnar synostosis with use of a free vascularized fascio-fat graft.

We present the results of a new mobilization procedure for the treatment of a congenital proximal radioulnar synostosis in seven patients. The operative procedure included separation of the synostosis and placement of a free vascularized fascio-fat graft to prevent recurrent ankylosis. The average age at the time of the operation was eight years and two months (range, six years and four months to eleven years and ten months). All of the patients were boys who had no other congenital anomalies. The radial head was dislocated in all seven patients (anteriorly in two and posteriorly in five). The final four index operations included an osteotomy of the radius in order to reduce the dislocated radial head. The average duration of follow-up was three years and eight months (range, two years and four months to four years and five months). Preoperatively, the patients had had difficulty with holding a bowl of soup and accepting objects, such as coins, into the palm. Postoperatively, they were able to perform these activities. None of the patients had recurrent ankylosis or loss of the flap. The average supination was 26 degrees (range, 10 to 45 degrees), and the average pronation was 45 degrees (range, 10 to 80 degrees). The four patients who had had an osteotomy of the radius in addition to the index procedure did not have a dislocation of the radial head and had an average arc of motion of 83 degrees of pronation and supination. The three patients who had not had an osteotomy had a dislocation of the radial head and an average arc of motion of 40 degrees after the index procedure. These findings demonstrate that separation of a congenital radioulnar synostosis with a vascularized fascio-fat graft and osteotomy of the radius can achieve pronation and supination of the forearm.

Sciatic function index, nerve conduction tests, muscle contraction, and axon morphometry as indicators of regeneration.

The purpose of this study was to determine which parameters were the best measure of nerve regeneration, assuming that the sciatic functional index (SFI) represented the "gold standard." Three different sciatic functional indexes and 11 commonly used electrophysiologic and morphologic indicators of regeneration were all determined in 24 rats 12 weeks after one of three lesions was created in the sciatic nerve. With linear regression analysis, only fiber/axon diameter ratio (D/d) and myelin thickness/axon diameter ratio showed statistically significant correlations with sciatic functional index (r = 0.55 and 0.53, respectively). The other 11 parameters had poorer correlation. Therefore, if sciatic functional index is the best measure of comprehensive nerve function, then other parameters are not. It is probable that each parameter measures some different component of the regeneration process. A stepwise multiple linear regression analysis produced a model that included D/d, nerve conduction velocity, and nerve action potential amplitude that gave a slightly better correlation (r = 0.67). The relatively poor correlation between sciatic functional index and the other parameters of nerve function indicates that all nerve regeneration studies must be interpreted carefully before comparisons are made. Furthermore, the best measure of nerve function remains unproved or undiscovered in the experimental animal.

Functional degradation of the rabbit sciatic nerve during noncompressive segmental ischemia.

The purpose of this study was to evaluate functional degradation in a nerve with a local ischemic segment created without a direct compression effect. Ischemia of one segment of a rabbit sciatic nerve was induced by stripping the nerve's extrinsic blood supply along 15 cm. Blood flow of both in situ and ischemic nerves was quantitatively measured with radioactive microspheres in six serial segments in seven animals. The flow in one middle segment of the stripped nerve was significantly reduced to 0.1 ml/min per 100 g (p = 0.006). In another eight animals, both in situ and stripped nerves were metabolically challenged with repetitive stimuli (200 Hz). Conduction velocity and peak amplitude were measured before stimuli, after 30 and 60 minutes of stimuli, and after a 30-minute recovery period. Conduction velocity was reduced in both nonischemic and stripped nerves during prolonged repetitive stimulation. Peak amplitude was reduced slightly in the nonischemic group and markedly in the stripped group. Normal or higher values were seen again in both groups during the recovery period. It was demonstrated, therefore, that conduction properties of the nerve, especially amplitude, can be affected by localized ischemia in one segment.

Vascularized bone grafts for congenital pseudarthrosis of the tibia.

Eight vascularized fibula grafts and two vascularized rib grafts were used for the treatment of 10 Boyd's Type II congenital pseudarthrosis of the tibia. All but one vascularized fibula graft united within 4 months. The two vascularized rib grafts did not unite until receiving a conventional bone graft. Nine spontaneous fractures were seen in four patients; all were subsequently treated successfully with cast or conventional bone graft. Corrective osteotomies were done in two patients. Follow-up averaged 8 years and 5 months (range, 5 years and 1 month to 14 years and 4 months). Average age at end of follow-up was 13 years and 6 months (range, 7 years and 10 months to 20 years and 4 months). After bony union was achieved, shortening of the affected leg averaged 3.8 centimeters, flexion deformity averaged 20 degrees, and valgus deformity averaged 24 degrees. In three patients, whose leg discrepancy averaged 4.9 centimeters, the leg was lengthened at an average patient age of 13 years and 9 months (age range, 11 years and 7 months to 15 years and 2 months). The resulting limb length discrepancy averaged 2.2 centimeters. Vascularized bone grafting is a reliable technique for achieving bony union in congenital pseudarthrosis of the tibia. Residual shortening may be corrected later by limb lengthening.

Free vascularized medial plantar flap with functioning abductor hallucis transfer for reconstruction of thenar defects.

We devised a medial plantar flap with a functioning abductor hallucis for simultaneous reconstruction of thenar skin and muscle defects. The anatomy of the flap was studied in five cadaver dissections before surgical attempts were made in patients, who in this series included three men and one woman (average age 38 years, range 26 to 50 years). All patients were followed a minimum of 3 years (average 3 years and 9 months). In all cases, voluntary abduction of the thumb by the transferred abductor hallucis was achieved and confirmed by electromyography. The functioning medial plantar flap provides not only stable skin to the thenar area with sufficient thenar bulk but also satisfactory abduction of the thumb.

Blood flow of segmentally divided and folded nerve.

The integrity of the blood supply to three equal segments of a nerve was determined, after the nerve was cut and folded but with its epineurial vasculature remaining intact. A 7.5-cm length of the rabbit sciatic nerve was elevated on a single pedicle. The epineurium was slit longitudinally, and the nerve fascicles were exposed, cut transversely into three equal segments, and then folded so that they were parallel. This is equivalent to a vascularized, folded, nerve graft in the clinical setting. Blood flow was quantified with microspheres in six rabbits, both after elevating the nerve and then again after it had been cut and folded. Mean blood flows in the three segments ranged from 4.4 to 6.2 ml/min/100 g after elevation, and from 4.7 to 8.0 ml/min/100 g after cutting and folding. Dividing and folding of the nerves did not significantly decrease blood flow in any of the nerve segments. The results support this technique as a valid method for vascularized, cable, nerve grafting.

Effect of electrostimulation on denervated muscle.

The influence of electrostimulation on denervated and reinnervated muscle was investigated. First, the left peroneal nerve was severed in rats. Wet weight and muscle fiber diameter of denervated anterior tibial muscle was compared as a percentage of contralateral muscle in stimulated and non-stimulated rats. In a second experiment, four weeks after the peroneal nerve was severed, the tibial nerve was cross-sutured to the distal stump of the peroneal nerve. Electrostimulation was continued in rats that had electrostimulation before nerve-crossing. Recovery of wet weight was assessed at eight weeks and at one year after nerve-crossing. The mean decrease in weight and fiber diameter of the denervated muscle was significantly less in the group that was electrostimulated for eight weeks. Recovery of weight of reinnervated muscle was significantly better in the electrostimulated group. Electrostimulation of denervated muscle retarded denervation atrophy and improved recovery after reinnervation.

Rapid histochemical identification of motor and sensory fascicles: preparation of solutions.

We report a rapid and inexpensive staining method for identification of motor and sensory fibers within 1 hour (intraoperatively). This method should be easy to use in any hospital where frozen histologic sectioning is available.

Functional results of vascularized versus nonvascularized nerve grafting.

Functional results of vascularized nerve grafts (VNG), end-to-end (E-E) repair, and nonvascularized nerve grafts (NNG) were compared using 75 rats. For all three groups, the sciatic function index (SFI) was measured for 12 weeks. For the vascularized nerve graft and nonvascularized nerve graft groups, it was measured every 4 weeks to week 36. The vascularized nerve graft and end-to-end repair groups showed significantly better recovery than the nonvascularized nerve graft group 4 weeks after surgery, and this pattern continued throughout the experiment. Results from the vascularized nerve graft and end-to-end repair groups did not differ significantly. Twelve weeks after surgery, morphologic and electrophysiologic assessments were used to compare the experimental and contralateral legs. The vascularized nerve graft group showed significantly better recovery than the nonvascularized nerve graft group on all measures except muscle weight and axon count, even though the grafts were completed in a normal bed.

Comments on ;Bayes statistical behavior and valid generalization of pattern classifying neural networks' [with reply].

In the above-titled paper (ibid., vol.2, p.471-475, July 1991), the authors claim that neural network classifiers duplicate the decision rule created by the empirical Bayes rule. The commenter states that this statement is, in fact, not generally true and points out an error in the proof. The commenter also shows that the related true statement about the relation between neural and Bayes classifiers is of no practical use. In reply, the authors show that the example that the commenter uses to disprove the equation is misleading. They refute the commenter's second point as well.

Sensory and motor fiber differentiation with Karnovsky staining.

We examined four acetylthiocholine methods based on Karnovsky's procedure--two fast-acting requiring 1 hour and two slow-acting requiring 24 hours. We compared these with our modification, which requires less than an hour and is simple to use. Rabbit sciatic nerves and spinal cords were used to compare methods. Our modification showed clearer differentiation than other fast-acting methods and staining identical to slow-acting methods. In blind examination of radial nerve specimens stained with our method, motor and sensory fascicles were correctly identified, showing sensitivity and specificity of 100%. In 12 clinical cases, our method produced staining in the proximal stump as long as 16 months after injury and in the distal stump as long as 5 days after injury. In 10 of 12 patients, this staining helped in aligning motor fascicles to motor fascicles and sensory fascicles to sensory fascicles.

Bayes statistical behavior and valid generalization of pattern classifying neural networks.

It is demonstrated both theoretically and experimentally that, under appropriate assumptions, a neural network pattern classifier implemented with a supervised learning algorithm generates the empirical Bayes rule that is optimal against the empirical distribution of the training sample. It is also shown that, for a sufficiently large sample size, asymptotic equivalence of the network-generated rule to the theoretical Bayes optimal rule against the true distribution governing the occurrence of data follows immediately from the law of large numbers. It is proposed that a Bayes statistical decision approach leads naturally to a probabilistic definition of the valid generalization which a neural network can be expected to generate from a finite training sample.

A neural network approach to a Bayesian statistical decision problem.

Generalized mean-squared error (GMSE) objective functions are proposed that can be used in neural networks to yield a Bayes optimal solution to a statistical decision problem characterized by a generic loss function.

Improvement in motor function after brachial plexus surgery.

Motor functional recovery of 52 patients with brachial plexus surgery followed up for more than 2 years was evaluated. Fifty-eight surgical procedures were done, including autologous nerve grafting (38 cases), neurolysis (14 cases), and neurotization (6 cases). Overall results, evaluated according to the 0 to 5 formula of the Medical Research Council, were as follows: good, 58%; fair, 15%; and poor, 27%. Good results were evident in 58% of patients with nerve grafts and in 64% of those with neurolysis. In patients with neurotization, no good recovery and only one fair recovery were seen. Patients with open injuries showed good recovery, whereas the group with closed injury showed good recovery in only 48%. Patients with closed injuries caused by traffic accidents showed a worse recovery than those caused by other means. Patients with closed injuries and nerve grafting done within 3 months of injury or neurolysis within 6 months showed better recovery.