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Biomedical subjects

N Maffulli

Publications and source records attributed to N Maffulli.

At least 37 records · Page 2Linked to original sources
PubMed2004

Triiodothyronine deiodinating activity in brown adipose tissue after short cold stimulation test in trained and untrained rats.

Interscapular brown adipose tissue (IBAT) activity is controlled by sympathetic nervous system, and factors that influence thermogenesis appear to be centrally connected to the sympathetic outflow to IBAT. Cold exposure produces a rise in BAT temperature, which is associated with an increased thyroid activity, elevated serum levels of 3,5,3'-triiodothyronine (T3), and an increased rate of T3 production. This study evaluated the effect of swimming training on 5'-triiodothyronine deiodinase (5'-D) activity in IBAT under normal environmental conditions and after short (30 min) cold exposure (TST stimulation test). 5'-D activity is lower in trained rats at basal condition, and TST increases 5'-D in IBAT of both untrained and trained rats. However, this increase is lower in trained rats. Training reduces the deiodinating activity in normal environmental conditions as well as after short cold exposure. Probably, other compensatory mechanisms of heat production are active in trained rodents.

Adipose Tissue, Brown↗
PubMed2003

Population based epidemiology of ankle sprains attending accident and emergency units in the West Midlands of England, and a survey of UK practice for severe ankle sprains.

OBJECTIVES: To estimate the incidence of ankle sprains and severe ankle sprains attending accident and emergency (A&E) units; to describe current practice for severe ankle sprains in A&E units in the United Kingdom. METHODS: Crude age and sex specific incidence rates were calculated for four health districts from cases ascertained from data on seven A&E clinical information systems. Case records of patients with ankle sprains at an A&E unit in another health district were audited and the proportion of severe ankle sprains calculated. UK A&E units were surveyed about their usual treatment of patients with severe ankle sprains. RESULTS: The estimate of the crude incidence rate of ankle sprains was a minimum of 52.7 per 10 000, rising to 60.9 (95% CI 59.4 to 62.4) when figures were adjusted for the proportion of patients without a diagnostic code (13.7%). There were important age-sex differences with unadjusted rates observed from 127.8 per 10 000 (CI 115.5 to 140.0) in girls aged 10-14 years to 8.2 (CI 4.2 to 12.3) in men aged 70-74 years. As 14% of ankle sprains attending A&E were classed as severe, this would equate to 42 000 severe ankle sprains per year in the UK. In the UK wide survey, there was a response rate of 79% (211 of 266). Among the responders, Tubigrip was used routinely in 55%, below knee casts in 3%, and braces in 2%. Boots were not used routinely in any unit. CONCLUSION: While there is considerable variation in severe ankle sprain management in UK A&E units, most are treated with the minimal mechanical support of Tubigrip.

Adolescent↗
PubMed2003

The effect of clamping a tensioned wire: implications for the Ilizarov external fixation system.

This study demonstrates that clamping a tensioned wire can cause a reduction in wire tension. Tension (about 1275 N) was applied to a wire that was subsequently clamped, using cannulated bolts, to the steel half-ring of an Ilizarov external fixator. The tension in the wire was monitored before, during and after clamping. The apparatus was disassembled and the deformations in the wire caused by the clamps were measured. This experiment was repeated 15 times. When the wire was clamped to the frame, the wire tension was reduced by 22 +/- 7 per cent (mean +/- standard deviation, SD). The drop in wire tension was linearly correlated (r = 0.96; p < 0.001) with the deformation caused by the bolts. A finite element (FE) model of the wire was also constructed. The model was pre-stressed (tensioned), and the clamping effect replicated. This analysis showed that clamping the wire could be considered to squeeze the wire outwards (like toothpaste from a tube) and so reduce its tension during fixator assembly. To assess the magnitude of this effect in the clinical situation, the FE model analysis was repeated to replicate clamping a 1.8-mm-diameter wire to a 180-mm-diameter steel Ilizarov ring component. The analysis showed that for these conditions the tension reduced by 8-29 per cent. The results of this study highlight a general engineering problem: how can a tensioned wire be secured to a structure without an appreciable loss of tension? If the performance of the structure depends on the wire tension, this performance will change when the wire is secured.

Bone Wires↗
PubMed2003

Yielding of the clamped-wire system in the Ilizarov external fixator.

This study demonstrates that the clamped-wire system used to suspend bones within an Ilizarov external fixator yields when the perpendicular load exceeds 50 N per wire. Cyclic loading was applied to tensioned wires clamped within an Ilizarov ring component, with steadily increasing load amplitude. Wires were tested at four initial tension settings. The amount of energy lost within the clamped-wire system per load cycle was calculated for every test. The results showed that there was a consistent trend to increasing non-recoverable energy loss per load cycle when peak loads exceed 50 N for all initial tension settings. A finite element (FE) model replicating the experimental conditions was performed to investigate the levels of stress within the loaded wires. The FE model analyses showed that high stresses were generated in the wires close to the clamping sites, and that the stress levels could reasonably be expected to exceed the material yield stress when loaded to about 55 N, for all initial tension settings. The results show that material yield, accompanied by some wire slippage through the clamps, is responsible for system yield, in agreement with previous studies. Although the initial wire tension has an appreciable effect on the wire stiffness, it did not affect the elastic load range of the clamped-wire system. To prevent yield of the clamped-wire system in practice, the fixator should be assembled with sufficient wires to ensure that the load transmitted to each wire by the patient does not exceed 50 N.

Bone Wires↗
PubMed2003

Local flap coverage for soft tissue defects following open repair of Achilles tendon rupture.

The authors assessed the long term clinical and functional results following local flap coverage (medial plantar flap, peroneal reverse flow island flap, posterior tibial reverse flow flap) in 11 patients who developed wound complications after open repair of a ruptured Achilles tendon. At the latest follow-up, seven patients had achieved a good result, having returned to their pre-injury activities. All patients were able to stand on tiptoes unaided, and were able to walk without aid. In our hands, local flaps are a reliable means of treating skin defects following open repair of subcutaneous ruptures of the Achilles tendon.

Achilles Tendon↗
PubMed2003

Parental influence on sport participation in elite young athletes.

AIM: To ascertain how talented young British swimmers, gymnasts, tennis and soccer players are introduced to their sport, and to identify how they are encouraged into intensive systematic training. METHODS: Two hundred and eighty-two elite young athletes (aged 8 to 17 yrs) and their parents were interviewed in their homes to identify how and why they started intensive training. RESULTS: Of the 4 sports studied (soccer, gymnastics, tennis, and swimming), parents of swimmers were more likely introduce their children to the sport (70%), while parents of gymnasts (42%) were the least likely to do so. However, in this sports parents played a lesser role in the transition to intensive training (6% and 5%, respectively). Nearly half the soccer players (47%) became involved in the sport because of their own interest, with the majority making the transition to intensive training because of encouragement by a coach (65%). Self-motivation (27%) and parental influence (57%) brought children into tennis with 25% of the young athletes in the sample autonomously deciding to start intensive training. Children from the lower socio-economic classes were underrepresented, and the total number of 1-parent families (5.3%) was considerably less than current British national norms (16.1%). CONCLUSION: In Britain, young athletes' involvement in high level sport is heavily dependent on their parents, with sports clubs and coaches playing an important later role. In the present socio-economic and cultural situation, many talented youngsters with less motivated parents will not undertake sport. Talented youngsters from a poorer economic background will be heavily disadvantaged, especially in sports such as tennis.

Adolescent↗
PubMed2003

No adverse effect of early weight bearing following open repair of acute tears of the Achilles tendon.

AIM: To study the effects of early weight bearing following acute repair of ruptured Achilles tendon. METHODS: Using a comparative longitudinal study design, following repair of an Achilles tendon rupture, patients in Group 1 were immobilised with their ankle in gravity equinus, were encouraged to weight bear on the operated limb as soon as possible to full weight bearing, and received a single a cast change at 2 weeks, when the ankle was immobilised in a plantigrade position. Patients in Group 2 were immobilised with their ankle in full equinus, and received a cast change at 2 weeks, when the ankle was immobilised in mid equinus, and at 4 weeks, when the ankle was immobilised in a plantigrade position. They were advised to weight bear 4 weeks from the operation. RESULTS: Patients in Group 1 attended less outpatient visits, completely discarded their crutches at an average of 2.5 weeks from the operation (Group 2: average of 5.7 weeks from the operation), (p=0.013), and a greater proportion of them were satisfied with the results of surgery. At ultrasound scan, the average thickness of the repaired tendon was 12.1 mm (SD 2), with no difference in the thickness of the ruptured tendon regardless of the method of postoperative management. There was no significant difference in isometric strength between the two groups of patients. CONCLUSION: Early weight bearing with the ankle plantigrade is not detrimental to the outcome of repair following rupture of the Achilles tendon.

Achilles Tendon↗
PubMed2002

A study of the mechanical stability of scoliosis constructs using variable numbers of sublaminar wires.

Sublaminar wiring with posterior instrumentation is one of the methods used when long fusions involving 10-12 thoracolumbar levels are required. Classically, wires are used at every consecutive level to make the construct as rigid as possible, although complications like dural tears, cerebrospinal fluid leak, and neurological deficit have been reported during their passage. We compared the mechanical stability under torsional strain of five specimens of each of three construct designs, by static and fatigue testing, using an electro-servo-hydraulic testing machine. In construct A, a contoured Hartshill rectangle was used from T2 to L2, with sublaminar wires passed at every level. In construct B, the Hartshill rectangle was wired to the spine at every alternate level. In construct C, every alternate level was wired except at the proximal end, where two consecutive levels were wired. Industrially fabricated spine models were used to prepare these constructs. The intervertebral motion within the construct was measured using the Fastrak magnetic field sensor device. On static testing, no statistically significant difference was found in the rotational displacement of the three construct designs. On fatigue testing, all samples of construct B consistently failed, with breakage of the wire at the most proximal level on the left side. But on adding additional wires to the next level (construct C), all five samples withstood fatigue testing at 300 N load to three million cycles. We conclude that wiring alternate levels instead of every level does not compromise the stability of the construct, provided that the most proximal two levels are consecutively wired. This practice would minimise the risk of dural tears and cord damage during wire passage and reduce surgical time, not to mention the economic benefits.

Biomechanical Phenomena↗
PubMed2002

The treatment of open tibial fractures and of tibial non-union with a novel external fixator.

We report the results of external fixation in 29 patients treated for tibial fractures and tibial non-union using a novel multi axial external fixator (MAXX) followed prospectively until bony union. The results of treatment were classified according to the Association for the Study and Application of the Method of Ilizarov (ASAMI). Overall, 13 patients had excellent bone results; 13 had good bone results; two had fair bone results, and 1 patient had poor bone results. Regarding functional results, 21 patients had excellent results; 6 obtained good results; none had fair results, and two had poor results. Acute patients did better functionally than chronic patients. This fixator is safe and versatile, although the indications for its use are very specific.

Adolescent↗
PubMed2002

Achilles tendinopathy: some aspects of basic science and clinical management.

Achilles tendinopathy is prevalent and potentially incapacitating in athletes involved in running sports. It is a degenerative, not an inflammatory, condition. Most patients respond to conservative measures if the condition is recognised early. Surgery usually involves removal of adhesions and degenerated areas and decompression of the tendon by tenotomy or measures that influence the local circulation.

Achilles Tendon↗
PubMed2002

Ultrasound changes to intramuscular architecture of the quadriceps following intramedullary nailing.

BACKGROUND: Disuse atrophy is the basis for profound physiological changes of the muscles of immobilised limbs. The aim of this study was to use high resolution real-time ultrasonography (HRRTU) to assess the quadriceps musculature and to try and measure atrophy. METHODS: We monitored the effects of enforced reduction of mobility due to trauma on the intramuscular architecture of the quadriceps using HRRTU in 13 skeletally mature male patients (43.2 years, range 16 to 82 years), with an isolated unilateral diaphyseal fracture of the femur or of the tibia. All patients had undergone interlocked intramedullary nailing (IIN). Using HRRTU, the pennation angles and muscle fibre lengths of vastus lateralis, the cross sectional area (CSA) of the rectus femoris, and the quadriceps muscle layer thickness (MLT) were measured in the injured and the normal contralateral limb. RESULTS: Repeated measurements showed the technique of measurement of the variables used in this study to be highly reproducible. There was a significant difference in the angle of pennation of the vastus lateralis in the nailed (15.4 degree) and the unnailed limb (21.2 degree), documenting that muscle atrophy causes a change to muscle architecture that results in a significant decrease in pennation angle (p=0.0002). The muscle fibre length was significantly different (p=0.002) and there was a significant correlation between pennation angle and muscle fibre length (r=-0.51, p=0.001). There was also a significant difference in the quadriceps MLT (p=0.001) and CSA of the rectus femoris (p=0.0004) implying that the whole of the quadriceps muscle is affected. CONCLUSIONS: These simple, reproducible, non-invasive ultrasound measurements can easily demonstrate differences in the quadriceps morphology in the nailed and unnailed limb, which could allow individual exercise programme prescription.

Adolescent↗
PubMed2002

Surgical management of tennis elbow.

BACKGROUND: To ascertain whether there were any differences in the outcome of release of the common extensor origin and release of the common extensor origin and drilling of the lateral epicondyle in the management of recalcitrant tennis elbow. METHODS: One hundred and eleven patients (125 elbows; 40 males, median age: 47 years; 71 females, median age: 45 years) entered the study. The minimum follow-up period was 2 years (average follow-up: 52.8 months). Patients were reviewed at 2 and 6 or 8 weeks, and 3 and 6 months after surgery. If a complication ensued, or if a patient did not report improvements, they were followed up for at least 1 year postoperatively. Two years after the recruitment period had ended, telephone interviews were performed. We used a 1 to 10 scale when enquiring about pain, both preoperative and postoperative, with 1 as the best score and 10 the worst. We also determined patient satisfaction, grip strength, and elbow function. RESULTS: Seventy-five percent of patients had excellent or good results, with 73% of them being satisfied with the results of surgery. There was no statistical significance in the outcome of the 2 procedures (chi-square, p=0.488). There were no statistically significant differences between the 2 procedures regarding pain, satisfaction, elbow function, and grip strength. CONCLUSIONS: Release of the common extensor origin at the elbow is a relatively simple operation, and produces reliable long term relief of tennis elbow pain in at least 70% of patients.

Adolescent↗