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PubMed2000

Changes in canine peripheral nerves during experimental callus distraction.

In 24 beagles, lengthening of the right tibia was performed by callus distraction after osteotomy and application of a ring fixator. Distraction was started the fifth day after surgery with a distraction rate of 0.5 mm twice per day and ended after 25 days. A control group of six additional dogs underwent tibial osteotomy and external fixation without distraction. Twelve animals with leg lengthening and three animals without leg lengthening were sacrificed immediately after the distraction period of 25 days (Group A), the remaining 15 dogs were sacrificed after an additional consolidation phase of another 25 days (Group B). From the distracted right leg and from the left control side of each animal, the tibial and peroneal nerves were removed and studied by means of morphometric analysis of semithin sections and electron microscopic study. The authors reported only minor alterations of the myelinated nerve fibers consisting in relatively thin myelinated remyelinating nerve fibers, single axon degeneration, or macrophages. There was no axonal sprouting. In contrast, electron microscopic study disclosed signs of late Wallerian degeneration and axonal regeneration of the nonmyelinated axons. Morphometric analysis of the peroneal nerves revealed a significant increase of fiber density and a reduced mean axon and fiber diameter in the consolidation period (Group B). Similar changes were found in the tibial nerves in Group A and disappeared in the consolidation phase (Group B). These features indicate that callus distraction leads to moderate degenerative changes, followed by repair mechanisms, almost complete recovery, and some nerve fiber growth.

Animals↗
PubMed1998

Biomechanical and densitometric bone properties after callus distraction in sheep.

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.

Absorptiometry, Photon↗
PubMed2003

P0 mRNA expression increases during gradual nerve elongation in adult rats.

Leg lengthening with nerve elongation is a common clinical treatment. We investigated morphological and molecular changes in peripheral nerves associated with femoral lengthening using animal models. Sciatic nerves of 13 week old male Wistar rats (n = 35) were elongated indirectly by leg lengthening for 14 days at 1 mm/day. At 3, 7, 14, 21, and 35 days following initiation of elongation, sciatic nerves on the elongated side and contralateral (control) side were excised at the midpoint of the femur. Internodal length was increased by 17%. Light and electron microscopic observation of transverse sections at 14 days showed elongated nerves appearing similar to control nerves with no degenerating axons and normal myelin thickness. We next examined changes of mRNA expression of a major myelin glycoprotein, P0, in elongated nerves using a quantitative reverse transcription-polymerase chain reaction and in situ hybridization. P0 mRNA expression in elongated nerves was increased during the first 3 weeks, with expression reaching 160% of control nerve expression at 14 days. Results of in situ hybridization were confirmatory. We concluded that myelin synthesis occurred during gradual nerve elongation. In adulthood, Schwann cells retain ability to synthesize myelin in response to nerve stretching.

Animals↗
PubMed1995

[The effect of 2 beta-(3-hydroxypropoxy)-1 alpha, 25-dihydroxyvitamin D3 (ED-71) on callotasis in rabbit].

To evaluate the effects of 2 beta-(3-hydroxypropoxy)-1 alpha, 25-dihydroxyvitamin D3 (ED-71) on callotasis, we measured the bone mineral content (BMC) using dual energy X-ray absorptiometry (DXA) and compared the results with radiographical and histological findings, in an experimental model. Leg lengthening by callotasis was performed on 37 10-week-old Japanese white rabbits. The rabbits were divided into two groups; those in Group A (n = 19) received no medication and those in Group B (n = 18) received ED-71 (0.05 micrograms/kg body weight) twice a week following osteotomy. In both groups, from 10 days after the osteotomy, the bone was lengthened a total of 10 mm at a rate of 0.5 mm every 12 hours (1.0 mm/day) for a further 10 days. After completion of distraction, the bone mineral content (BMC) of the newly formed bone at the site of lengthening was then measured by DXA each week for 15 weeks, and the DXA findings were compared with those from radiographical and histological studies. The BMC of the newly formed bone at the site of the lengthening in both groups increased and reached a peak at two weeks after completion of the distraction. Then, the BMC gradually decreased and reached a plateau after a further 8 weeks. The BMC in Group B was significantly higher than that in Group A, and this correlated with the radiographical and histological findings. We concluded that the change in BMC at the site of the lengthening corresponded with the radiographical and histological findings, and that ED-71 administration may increase the callus formation at the site of leg lengthening.

Animals↗
PubMed1991

[Biochemical and anatomic changes in the muscles after leg bone lengthening by the Ilizarov method].

In process of crus lengthening, following the method, given by Ilizarov G. A., with 22 adult patients have been studied the peculiarities of metabolic processes of muscle tissue of the lengthened segment as well as the muscle tissue structural changes. As the tests were used; determination of lactate dehydrogenase content and its isoenzymatic spectrum in the blood serum, the residual products of lactic and pyruvic acids glycolysis, relating to the higher indications of the internal medium of an organism; carboxylase activity detection. Energy provision of an organism was estimated according to the ATP content; anatomical state of muscles of the lengthened extremity segment and muscle tissue structure were estimated by means of contrast myography. Dynamics of biochemical indexes suggests that the sparing character of an operation, patient mobility from the first days, preservation of locomotive and supporting function contribute to prevention of metabolic disease and ensure earlier transformation of catabolic reaction to anabolic one. Carboxylase and lactate-dehydrogenase activity increase indicates the biochemical adaptation of an organism. Metabolic changes well correlate with the detected structural changes in the lengthened crus muscles.

Adenosine Triphosphate↗
PubMed2006

Loading the limb during rhythmic leg movements lengthens the duration of both flexion and extension in human infants.

Sensory input is critical for adapting motor outputs to meet environmental conditions. A ubiquitous force on all terrestrial animals is gravity. It is possible that when performing rhythmic movements, animals respond to load-related feedback in the same way by prolonging the muscle activity resisting the load. We hypothesized that for rhythmic leg movements, the period (extension or flexion) experiencing the higher load will be longer and vary more strongly with cycle period. Six rhythmic movements were studied in human infants (aged 3-10 mo), each providing different degrees of load-related feedback to the legs during flexion and extension of the limb. Kicking in supine provided similar loads (inertial) during flexion and extension. Stepping on a treadmill, kicking in supine against a foot-plate, and kicking in sitting loaded the legs during extension more than flexion, whereas air-stepping and air-stepping with ankle weights did the opposite. Video, electrogoniometry, surface electromyography, and contact forces were recorded. We showed that load-related feedback could make either the duration of flexion or extension longer. Within the tasks of stepping and kicking against a plate, infants who exerted lower forces showed shorter extensor durations than those who exerted higher forces. Because older babies tend to step with greater force, we wished to rule out the contribution of age. Eight babies (>8 mo old) were studied during stepping, in which we manipulated the amount of weight-bearing. The same effect of load was seen. Hence, the degree of loading directly affects the duration of extension in an incremental way.

Aging↗
PubMed2006

[Total hip arthroplasty for Crowe type-IV development dysplasia of hip in adults].

OBJECTIVE: To determine the operation procedure of total hip arthroplasty (THA) for Crowe type-IV developmental dysplasia of hip and its relationship with nerve injury. METHODS: A consecutive series of 39 THAs was performed for Crowe type-IV developmental dysplasia of hip in 35 patients (all female). The mean age of the patients at the time of surgery was 46 years (range 36 - 56 years). Thirty-five hips in 31 patients were followed up. The average follow-up period of the whole series was 4 years (range 1 - 8 years). All procedures were carried out through a lateral-posterior approach. In 33 of 35 hips, the cup was inserted in the "true" acetabulum. All the prostheses used were cementless, except for 5 cemented femoral stems in 5 patients. Each patient was evaluated clinically and by radiographs before the operation and during the follow-up period, according to the Harris hip score (HHS). RESULTS: None of the cups and stems were revised for aseptic loosening, dislocation or infection during the follow-up period. The mean preoperative HHS was 43 compared with the postoperative HHS of 87. The mean amount of postoperative leg lengthening was 5 cm (range 4 - 6 cm). CONCLUSIONS: The reconstruction of the hip at the level of the "true" acetabulum through a lateral-posterior approach is a safe and effective procedure of THA for Crowe type-IV developmental dysplasia of hip in adults. Acute leg lengthening of less than 6 cm could not cause nerve injury.

Adult↗
PubMed2006

Long-term review of five leg replantations: emergency strategy and examples of lengthening of the leg on nerve regeneration.

The success rate for leg replantation has improved with the development of shortening-lengthening protocols. We checked whether this success was maintained long term in five cases of emergency reimplantation. The significant initial shortening of 93 mm, on average, enabled direct internal osteosynthesis, secondary lengthening was initiated swiftly, in the proximal metaphyseal area, and average lengthening was 85 mm. Consolidation was achieved in all cases within normal time periods, with an average inequality in residual length of 8mm. The speed of nerve regeneration was on average 1.926 mm/day, twice faster than usual after simple nerve suturing. At average follow-up of more than 11 years, all patients were walking. We conclude that nerve lengthening stimulates nerve regeneration, and that the results of this protocol, involving extensive initial debridement compensated by secondary lengthening, have enabled the limitations on unilateral leg replantation to be reduced.

Adult↗
PubMed1999

Growth hormone therapy in hypochondroplasia.

Patients with hypochondroplasia present with variable phenotypes. Children with severe short stature and disproportion of the body segments usually have the mutation Asn540Lys. They respond to growth hormone (GH) therapy with an increase in spinal length and, coupled with a surgical leg-lengthening procedure, it is possible for some patients to achieve adult heights within the normal range. Some children who present with proportionate short stature and hypochondroplasia fail to increase their growth rate at puberty, although the growth spurt can be restored by GH therapy. Others, with an identical presentation, seem to grow normally during puberty. At present, there is no way of predicting who will undergo a normal pubertal growth spurt. We therefore monitor all patients during childhood and give GH treatment only to those patients who fail to develop a growth spurt at puberty. Severe cases may occasionally need treatment before puberty if their growth velocity is compromised, but these will probably also be candidates for a surgical leg-lengthening procedure.

Achondroplasia↗
PubMed1966

Lengthening a leg.

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Leg Length Inequality↗
PubMed1991

Preventing and overcoming equinus contractures during lengthening of the tibia.

The new technique of leg lengthening and deformity correction with different types of external fixators has given the orthopedic surgeon a tool that allows correction of very difficult deformities and leg length discrepancies of the lower extremity. Dissemination of this knowledge has demonstrated that there are many associated problems with these techniques: one of which is resulting equinus deformity after correcting the tibia. The shortened soleus-gastrocnemius-achilles tendon complex is the cause of this deformity. Several techniques are suggested on avoiding this complication and how to correct it once it has occurred.

Bone Lengthening↗
PubMed2002

Malleolus externus plasty for joint reconstruction in fibular aplasia: preliminary report of a new technique.

The instability of the upper and the lower ankle joint represents a serious problem in patients with fibular aplasia. None of the previous techniques demonstrated at least sufficient results. In this report we present a new technique of malleolus externus plasty applied in a 5 1/2-year-old boy with fibular aplasia (type II according to Coventry and Johnson or type Ib according to Achtermann and Kalamchi) with a 6 cm length deficiency of the lower leg and 1 cm of the upper leg. Furthermore, he showed a tibial antecurvation deformity of 20 degrees, a fourth ray foot with adduction deformity of the hindfoot, cutane syndactyly D 2-4, and a hallux varus. This new technique works on the following principle. A triangular iliac crest transplant is implanted with an apophysis and the annexing fascia glutealis, including the osseous part of the transplant, in the lateral distal tibia in a way that the growing apophyseal part lays distally covering the lateral talus. Gluteal fascia annexed to the apophysis was used for the reconstruction of a lateral tendon. Using a ring fixator the transplant is fixed and coincidentally the lower leg lengthened and the axis corrected. The axis deformity and the leg-length deficiency of 7 cm were equalized. The fixator could be removed after 6 months. Radiologically, an entire integration of the iliac crest transplant was found. Magnetic resonance imaging showed it had sufficient circulation. The reexamination 2.5 years later demonstrated a simultaneous growth of the malleolus externus and the distal tibia and stable ankle joints with sufficient mobility and full weight-bearing capability. For support of the foot the boy uses ready-made shoes with curved arch supports. In conclusion, using this new technique an individually adapted lateral malleolus with growth-potential can be constructed that stabilizes the foot and the ankle joints. Thus, reluxations of the foot specifically in relation to lengthening of lower legs can be avoided with concurrent preservation of the range of movement of the ankle joint.

Ankle Joint↗
PubMed1990

Effect of direct current stimulation on bone growth after distraction epiphysiolysis of the rabbit tibia.

The effect of direct current stimulation on bone formation during limb lengthening was tested in a lower leg lengthening model in the rabbit. Limb lengthening was performed by distraction epiphysiolysis. A specially designed external distraction device was placed at the tibia. The distractor allowed 10 mm of lengthening in 4 weeks. Two weeks after starting the distraction, a platinum electrode was passed through the anterior cortex below the tibial tuberosity and advanced via the medullary cavity so that the tip rested in the elongated zone. Stimulation started at the time of placement of the electrodes and was continued for 3 weeks. The electrode in the elongated zone served as the cathode; the anode was placed subcutaneously. A 20 microA stimulus was selected. A control group received the same treatment without stimulation. Bone formation in the elongated zone was evaluated by histology and scintigraphy. The data from this experiment show that direct current stimulation in the early phase of a limb lengthening procedure had no effect on the extent of bone formation in the elongated zone.

Animals↗
PubMed1989

[Management of femur shaft fracture in the growth age with the fixateur externe].

Non-operative management is still the treatment of choice today for femoral shaft fractures in children. Indications for operative intervention would include: - the child with multiple injuries, particularly with severe head injuries, in those patients with severe soft tissue damage associated with the fracture; in cases where the reduction is difficult to maintain, as in subtrochanteric fractures; and in children who are not suitable for management with traction. Since 1984, 16 children have had their femoral shaft fractures stabilized by external fixation (Monofixateur) here in the Trauma Department of the Hannover Medical School. The mean age of the patients was 10.3 years (seven to sixteen years). All cases were closed fractures with mild or moderate soft tissue damage. Eleven of the patients had a multiple injury, and four had subtrochanteric fractures. The external fixation remained in place for a mean of 63 days in those patients exclusively treated by this method. In four of the earlier cases there was a Schanz's screw infection and three of these required removal of the external fixation and treatment in a hip spica. After modifying the technique of Schanz's screw insertion, no further infections were seen. Fourteen of the sixteen children were reviewed, with a mean follow up of 21.7 months. None of the children who had been completely managed by this fixation had any clinically relevant malalignment. Six cases had leg lengthening of up to two centimetres. Leg length differences were seen more frequently and more severely in those cases where external fixation was delayed.

Adolescent↗
PubMed2001

Changes in canine skeletal muscles during experimental tibial lengthening.

In 24 beagles, lengthening of the right tibia was performed by callus distraction after osteotomy and application of a ring fixator. Distraction was started at the fifth postoperative day, with a distraction rate of 0.5 mm twice per day, and ended after 25 days. A control group of six additional dogs underwent tibial osteotomy and external fixation without distraction. Twelve animals with and three animals without leg lengthening were euthanized immediately after the distraction period of 25 days (Group A); the remaining 15 dogs were euthanized after an additional consolidation phase of another 25 days (Group B). From the distracted right leg and from the left control leg the tibialis anterior muscle, extensor digitorum longus muscle, peroneus longus muscle, and gastrocnemius muscle were removed and studied by means of routine histologic, histochemical, and immunohistochemical analyses, and electron microscopic examination. The muscles of the control group showed no differences between the right and left sides. However, in the other 24 dogs of Groups A and B, the authors saw marked alterations affecting only the lengthened muscles but not the muscles of the control limbs. These changes were highly significant and included muscle fiber degeneration and regeneration, target fibers, central cores, minicores, marked endomysial and perimysial fibrosis, and atrophy of Type 1 and Type 2 fibers. In the consolidation period (Group B) fiber type grouping indicated that reinnervation had occurred. In addition, an increase in satellite cells and myoblasts and proliferation of nuclei were observed. The findings of the current study indicate that leg lengthening results not only in muscle fiber degeneration followed by regeneration and reinnervation but also in formation of new muscle tissue.

Animals↗