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PubMed1998

Innervation pattern of a pool of nine excitatory motor neurons in the flexor tibiae muscle of a locust hind leg

The flexor tibiae muscle of a locust hind leg consists of 10-11 pairs of fibre bundles in the main body of the muscle and a distal pair of bundles that form the accessory flexor muscle, all of which insert onto a common tendon. It is much smaller than the antagonistic extensor tibiae muscle and yet it is innervated by nine excitatory motor neurons, compared with only two for the extensor. To determine the pattern of innervation within the muscle by individual motor neurons, branches of the nerve (N5B2) that supplies the different muscle bundles were backfilled to reveal somata in the metathoracic ganglion. This showed that different muscle bundles are innervated by different numbers of excitatory motor neurons. Physiological mapping of the innervation was then carried out by intracellular recordings from the somata of flexor motor neurons in the metathoracic ganglion using microelectrodes. Spikes were evoked in these neurons by the injection of current, and matching junctional potentials were sought in fibres throughout the muscle using a second intracellular electrode. Each motor neuron innervates only a restricted array of muscle fibres and, although some innervate a larger array than others, none innervates fibres throughout the muscle. Some motor neurons innervate only proximal fibres and others only more distal fibres, so that the most proximal and most distal bundles of muscle fibres are innervated by non-overlapping sets of motor neurons. More motor neurons innervate proximal bundles than distal ones, and there are some asymmetries in the number of motor neurons innervating corresponding bundles on either side of the tendon. Individual motor neurons cause slow, fast or intermediate movements of the tibia, but their patterns of innervation overlap in the different muscle bundles. Furthermore, individual muscle fibres may also be innervated by motor neurons with different properties.

Journal Article↗

PubMed1998

Relation between mechanical stiffness and vibration transmission of fracture callus: an experimental study on rabbit tibia.

It has been suggested that the vibration transmission across a fracture is affected by the stages of healing of the fracture callus. This study aims to correlate the change in vibration transmission with mechanical stiffness of the callus measured by three-point bending. The right tibiae of male, three-month old local albino rabbits were osteotomized and stabilized by intramedullary fixation following open reduction. The intramedullary rods were removed on the 15th, 28th, 42nd and 90th days postoperatively and the tibiae were excised for vibration, three-point bending and bone mineral density analysis by quantitative computerized tomography (QCT). Optimum time for clinical weight bearing was determined by checking the convergence of the vibration parameters of the fractured tibia to those of the unfractured contralateral. The conclusions obtained from curvature analysis, based on vibration experiments, were in considerable correlation (Spearman's rank correlation coefficient r = 0.93, p = 0.003) with the conclusions obtained from the three-point bending test data which reflected the mechanical condition of the bone by direct means. However, no correlation between bone mineral density change and vibration transmission was noted.

Animals↗

PubMed2003

Age-related variation in quantitative ultrasound at the tibia and prevalence of osteoporosis in native Chinese women.

This study investigated the variations in age-related speed of sound (SOS) at the tibia and prevalence of osteoporosis in native Chinese women, and establishment of a reference database by quantitative ultrasound. SOS at the right midtibia was measured using a quantitative ultrasound device (SoundScan 2000, Myriad Ultrasound Systems, Israel) in 1596 healthy Chinese women ranging from 12 years to 96 years of age. Healthy women were selected on the basis of (1). a detailed questionnaire about their medical history, (2). face to face questioning about their medical history, and (3). a physical examination. Women with a medical condition that required medication that affected bone metabolism or those who had had a pathologic or moderate traumatic fracture were excluded. We followed the diagnostic criteria provided by the instrument's manufacturer and equivalent to the WHO criteria (using the T-score cut-off that diagnoses 30% of the post-menopausal women aged >or =50 years with osteoporosis) as the diagnostic criteria for osteoporosis in this group of women. Data were analyzed in age groups divided by intervals of 5 years. The peak SOS at the tibia of 3991+/-68 m s(-1) (mean+/-SD) occurred in the 35-39 year age group and the T-score precision was 0.99 T-score units. The SOS value increased with age up to 34 years of age and then declined with age after 40 years of age with the rate of decrease at 9.68 m s(-1) per year. The curve representing the SOS change according to age is best fitted by the regression analysis of cubic model, and the cubic equation for SOS=3383+39.9 (age)-0.78 (age)(2)+0.0039 (age)(3) (R(2)=0.505, p=0.000). The T-score cut-off that diagnoses 30% of the post-menopausal women (n=559, mean age 63.2+/-8.97 years) aged >or=50 years with osteoporosis was SOS or=80 years, the prevalences of osteoporosis detected using equivalent to the WHO criteria were 0.39%, 9.27%, 30.3%, 58.4% and 69.0%, respectively. The prevalences detected following the manufacturer's diagnostic criteria (cut-off value: SOS<or=3800 m s(-1), T-score<or=-2.0) were 3.14%, 20.5%, 53.2%, 78.8% and 89.7%, respectively. There were significant differences in the prevalence between the diagnostic criteria in the various age groups (p=0.000-0.002). In 769 women from 40 years to 59 years of age, the mean SOS was significantly higher in pre-menopausal women (n=500) than in post-menopausal women (n=269) (3977+/-89 vs 3881+/-118 m s(-1), p=0.000). The prevalence of osteoporosis in these women was 0.40% in pre-menopausal women, 8.92% in post-menopausal women, respectively. There were significant differences in prevalence of osteoporosis between the two groups of pre- and post-menopausal women (p=0.000). In conclusion, SOS at tibia can provided useful information about bone status in the normative population of native Chinese women for determination of osteoporosis. The reference database based on these data will be appropriate for the diagnosis of osteoporosis by tibial quantitative ultrasound in native Chinese women.

Adolescent↗

PubMed2001

Fracture of the proximal tibia six months after Fulkerson osteotomy. A report of two cases.

The Fulkerson osteotomy has proved to be a reliable treatment for subluxation of the patella due to malalignment. Aggressive rehabilitation in the early postoperative period is unwise since the proximal tibia is weakened by the oblique osteotomy. Early weight-bearing and unrestricted activity have caused fractures in a few patients. Even late in the postoperative period the osteotomy may adversely influence the biomechanical properties of the proximal tibia. We describe two athletes who sustained a fracture of the proximal tibia, during recreational activities, six months after a Fulkerson osteotomy. Both had been bearing full weight for about ten weeks without complaint. Bony healing of the osteotomy had been demonstrated on plain radiographs at ten and at 12 weeks. After a Fulkerson osteotomy, jogging and activities which impose considerable impact force should be discouraged for at least nine to 12 months.

Adult↗

PubMed2004

Avulsed posterior edge of the tibia. Earle's or Volkmann's triangle?

The term Volkmann's triangle for the avulsed posterior edge of the tibia in fracture-dislocations of the ankle is incorrect. Volkmann did not publish any articles relating to the posterior edge of the tibia. Credit should go to Henry Earle, who was an outstanding British surgeon of the first half of 19th century. He described avulsion of the posterior edge of the tibia in 1828. In 1823 he also published a monograph entitled Practical observations in surgery in which he described a specially designed bed for the conservative treatment of proximal fractures of the femur.

Ankle Injuries↗

PubMed2005

Angle stable locking reduces interfragmentary movements and promotes healing after unreamed nailing. Study of a displaced osteotomy model in sheep tibiae.

BACKGROUND: Large interfragmentary movements may delay bone-healing. The hypothesis of the present study was that a reduction of interfragmentary movements, especially of torsional rotation and bending angles, would support the healing process and lead to improved healing following unreamed tibial nailing. The objective of this study was to investigate healing of an unstable tibial osteotomy site following stabilization with unreamed nailing with a modified tibial device that had angle stable holes for the locking bolts. We compared those findings with healing after stabilization of such sites with standard unreamed tibial nailing. The duration of the study period was nine weeks. METHODS: The site of a standardized displaced osteotomy (3-mm gap) in twelve ovine tibiae was stabilized with unreamed tibial nailing: six animals were treated with a modified nail that had angle stable holes for the locking bolts, and six were treated with standard unreamed tibial nailing. In vivo gait analysis with optical measurements of interfragmentary movements and simultaneous measurements of ground reaction parameters were performed three days after the operation and once weekly afterward. After the animals were killed at nine weeks, the treated and contralateral tibiae were explanted, the implants were removed, and radiographs were made and evaluated for bridged cortices. Each pair of tibiae was also mechanically tested until torsional failure, after which the whole callus region was subjected to histological and histomorphometric analysis. RESULTS: Throughout the examination period, the interfragmentary movements in all directions were significantly smaller in the group treated with the angle stable tibial nail than they were in the group treated with standard unreamed tibial nailing. The limbs treated with the angle stable tibial nails returned to almost full weight-bearing during the period of the investigation, whereas those treated with standard nailing did not. Histomorphometric analysis, radiographic data, and mechanical testing showed superior bone-healing following treatment with the angle stable tibial nail. CONCLUSIONS: Use of an angle stable tibial nail may help to reduce interfragmentary movements in vivo and thus lead to superior bone-healing compared with that following standard unreamed tibial nailing.

Analysis of Variance↗

PubMed2005

In vitro biomechanical comparison of a plate-rod combination-construct and an interlocking nail-construct for experimentally induced gap fractures in canine tibiae.

OBJECTIVE: To compare structural properties of a plate-rod combination-bone construct (PRCbc) and interlocking nail-bone construct (ILNbc) by use of an experimentally induced gap fracture in canine tibiae. SAMPLE POPULATION: 12 paired canine tibiae. PROCEDURE: Specimens were implanted with a plate-rod combination consisting of a 3.5-mm, limited-contact, dynamic-compression plate combined with an intramedullary rod or 6-mm interlocking nail. Ostectomy (removal of 10-mm segment) was performed. Paired constructs were loaded for bending, compression, or torsion measurements (4 constructs/group). Compliance was determined by fitting regression lines to the load-position curves at low (initial compliance) and high (terminal compliance) loads. RESULTS: Bending compliances did not differ significantly between constructs. For the ILNbc, initial compliance was greater than terminal compliance in compression and torsion. Initial compliance and terminal compliance for the PRCbc were similar in compression and torsion. Initial compliance in compression and torsion was greater for the ILNbc, compared with initial compliance for the PRCbc. Maximum deformations in bending and compression were similar between constructs; however, maximum torsional angle was significantly greater for the ILNbc, compared with values for the PRCbc. CONCLUSIONS AND CLINICAL RELEVANCE: The study documented that for an experimentally induced gap fracture in canine tibiae, a plate-rod combination is a significantly less compliant fixation method in torsion and compression, compared with an interlocking nail. Considering the deleterious effects of torsional deformation on bone healing, a plate-rod combination may represent a biomechanically superior fixation method, compared with an interlocking nail, for the treatment of dogs with comminuted tibial diaphyseal fractures.

Animals↗

PubMed1983

Stress-protection after external fixation on the intact rabbit tibia.

Bone loss due to the stress-protecting effect of a metal plate on intact bone is a well-known phenomenon. The purpose of the present study was to find whether a similar effect is caused by external fixation. External mini-fixation was applied on the intact rabbit tibial diaphysis of one leg. The other tibia served as control. The animals were sacrificed after 6 or 12 weeks, and both tibiae biomechanically tested in three-point bending. The bone mineral content was measured by photon absorptiometry. No significant changes in bone strength, stiffness or mineral content were found after 6 weeks. The strength and stiffness were significantly reduced after 12 weeks. The median strength and stiffness at that time were 87 and 88 per cent, respectively, in relation to the control bones. The mineral content in the bone segment which had been stabilized by external fixation was significantly reduced after 12 weeks (median 90 per cent of the values for the control bones). No significant change in the mineral content occurred at a level in the tibial diaphysis distal to the external fixation device. It is concluded that the stress-protecting effect caused by external mini-fixation on the rabbit tibia occurs later, and is less pronounced, than that caused by metal plates.

Animals↗

PubMed1991

Piroxicam-induced reduction in osteopenia after external fixation of rabbit tibia.

Twelve rabbits were treated with a unilateral external fixator in one tibia for 12 weeks, while the other tibia served as an intact control. Half of the animals were also treated with 10 mg/kg/day of piroxicam, given in two daily oral doses. Changes in bone mineral content were determined using single photon absorptiometry. After 12 weeks, we found a 3 percent decrease in the bone mineral content in the tibia of the animals treated with piroxicam versus 9 percent in the nonpiroxicam group (P = 0.04). In the femurs, there was an insignificant decrease in bone mineral, 2 percent (piroxicam) and 1 percent (nonpiroxicam) respectively. The results indicate that piroxicam may reduce the osteopenia caused by external fixation.

Absorptiometry, Photon↗

PubMed1996

Training increases the in vivo fracture strength in osteoporotic bone. Protection by muscle contraction examined in rat tibiae.

The effect of high-intensity training on the in vivo lower leg fracture strength during muscle contraction was investigated in osteoporotic rats. 20 Wistar rats were ovariectomized and given a low calcium (0.01%) diet. 7 weeks after ovariectomy they were randomized into training (T) and sedentary (S). The S group was kept cage-confined without any intervention. The T group ran on a treadmill with 10 degrees inclination 5/7 days for 8 weeks. A maximum intensity of 27 m/min was reached after 4 weeks. After 8 weeks, the right lower legs of the anesthetized animals were loaded in three-point ventral bending until fracture occurred during electrically-induced muscle contraction. The left tibiae were excised and fractured at the same level as the right tibiae. Weight gain was equal in the two groups. Energy absorption and deflection at fracture were significantly higher in the T group than in the S group in vivo during muscle contraction. In vitro, there were no significant differences in mechanical results. The mediolateral outer diameter was larger in the T group, and the maximal stress that the tibia could withstand was lower than in the S group. We conclude that 8 weeks of high-intensity training of osteoporotic rats increased the structural lower leg strength during muscle contraction. The reduced maximal stress in the training animals indicates a reduction in bone material quality. The increase of in vivo structural strength must reflect an increased protective effect of muscle contraction due to training.

Animals↗

PubMedDate not supplied

Comparison of normograde and retrograde intramedullary pinning of feline tibias.

This study evaluated the effects of normograde and retrograde intramedullary pinning of mid-diaphyseal fractures of the feline tibia on the anatomical structures of the stifle joint. Using the paired pelvic limbs from five mature feline cadavers, a transverse, mid-diaphyseal osteotomy was performed, and each tibia was pinned in a normograde or retrograde fashion. The stifle joints were examined to determine the pin exit site and measure the distance from the exit site to pertinent anatomical structures of the stifle joint. Neither normograde nor retrograde intramedullary pinning resulted in damage to the cruciate ligaments, menisci, intermeniscal ligament, femoral condyles, or joint capsule. The patellar tendon was penetrated in all five tibias during retrograde pin insertion.

Animals↗

PubMed2001

Metastatic fractures of the tibia.

Pathologic fractures of the tibia due to a metastasis are rare. The treatment of an established fracture is sometimes conservative, but more often surgical. The purpose of the surgical procedure is to improve the quality of life and the ambulatory status, to relieve pain and to facilitate activities of daily living and nursing care. Four cases of operatively managed metastatic fractures of the tibia are presented with emphasis on the surgical technique. The scarce literature on metastatic tibial fractures in reviewed. The operative technique to be used does not only depend on the location of the tumor but also on the primary tumor, the response to adjuvant therapy and the life expectancy. For metastatic shaft fractures an intramedullary nail, sometimes augmented with bone cement, is preferred. For distal or proximal fractures a compound osteosynthesis with plates and screws offers a good solution. In the epiphyseal and metaphyseal region of the tibia an amputation or a tumor prosthesis is the procedure of choice.

Activities of Daily Living↗

PubMed1999

[Application of repairing tibia and soft tissue defect with free fibula combined tissue grafting].

OBJECTIVE: To investigate a good method for repairing the long bone defect of tibia combined with soft tissue defect. METHODS: From 1988-1998, sixteen patients with long bone defect of tibia were admitted. There were 12 males, 4 females and aged from 16 to 45 years. The length of tibia defect ranged from 7 cm to 12 cm, the area of soft tissue defect ranged from 5 cm x 3 cm to 12 cm x 6 cm. Free fibula grafting was adopted in repairing. During operation, the two ends of fibular artery were anastomosised with the anterior tibial artery of the recipient, and the composited fibular flap were transplanted. RESULTS: All grafted fibula unioned and the flap survived completely. Followed up for 6 to 111 months, 14 patients acquired the normal function while the other 2 patients received arthrodesis of the tibial-talus joint. In all the 16 patients, the unstable ankle joint could not be observed. CONCLUSION: The modified method is characterized by the clear anatomy, the less blood loss and the reduced operation time. Meanwhile, the blood supply of the grafted fibula can be monitored.

Adolescent↗

PubMed2002

Congenital pseudarthrosis of the tibia: results of technical variations in the charnley-williams procedure.

BACKGROUND: Results of the Charnley-Williams method of intramedullary fixation for treatment of congenital pseudarthrosis of the tibia have varied, in part because of variations in surgical technique. The outcomes of three variations of this procedure were compared to determine which technique was the most likely to result in union. METHODS: The results in twenty-three consecutive patients with congenital pseudarthrosis of the tibia were reviewed at four to fourteen years following initial surgical treatment with an intramedullary rod. Three types of procedures were performed: type A, which consisted of resection of the tibial pseudarthrosis with shortening, insertion of an intramedullary rod into the tibia, and tibial bone-grafting combined with fibular resection or osteotomy and insertion of an intramedullary rod into the fibula; type B, which was identical to type A except that it did not include fibular fixation; and type C, which consisted of insertion of a tibial rod and bone-grafting but no fibular surgery. The outcome was classified as grade 1 when there was unequivocal union with full weight-bearing function and maintenance of alignment requiring no additional surgical treatment; grade 2 when there was equivocal union with useful function, with the limb protected by a brace, and/or valgus or sagittal bowing for which additional surgery was required or anticipated; and grade 3 when there was persistent nonunion or refracture, requiring full-time external support for pain and/or instability. RESULTS: Eleven patients (48%) ultimately had a grade-1 outcome; nine, a grade-2 outcome; and three, a grade-3 outcome. The final outcome was not associated with either the initial radiographic appearance of the lesion or the age of the patient at the time of the initial surgery. The results following type-A and B operations were better than those after type-C procedures. Surgery on an intact fibula resulted in a lower prevalence of grade-3 outcomes than was found when an intact fibula was not operated on (p = 0.05). Transfixation of the ankle joint by the intramedullary rod did not decrease the prevalence of grade-3 outcomes. CONCLUSIONS: There is little justification for a type-C operation, as it either resulted in a persistent nonunion or failed to improve an equivocal outcome in every case. Leaving an intact fibula undisturbed to maintain stability or length also was not successful in this series. In addition, the presence of fibular insufficiency (fracture or a pre-pseudarthrotic lesion) was highly prognostic for subsequent valgus deformity (occurring in ten of twelve cases), whether or not the fibula eventually healed.

Adolescent↗

PubMed2003

[The floating knee in adults: twenty-four cases of ipsilateral fractures of the femur and the tibia].

OBJECTIVES: We evaluated the presenting features of ipsilateral femoral and tibial fractures in adults, and the effects of both fracture type and severity of skeletal injury on the results. METHODS: The study included 24 patients (22 men, 2 women; mean age 38 years; range 17 to 75 years). According to the classification by Letts et al., the types of the fractures were as follows: type A (7), type B (2), type C (5), type D (7), and type E (3). Femur fractures were treated by locked intramedullary nails, AO plates, plate-screws, unilateral external fixator, or dynamic condylar screws, and tibia fractures by external fixator, plate-screws, locked intramedullary nailing, or with conservative methods. Amputation at the fracture level was required in a patient with type 3C open tibia fracture. The mean follow-up was 3.2 years (range 1.3 to 7 years). RESULTS: According to the criteria by Kalström and Olerud, the results were excellent in three patients, good in nine patients, fair in five patients, and poor in six patients. The mean skeletal injury scores were 4.4 and 3 in patients having fair and poor results and in those with good and excellent results, respectively. Fair and poor results corresponded to type A (1 patient), type C, type D, or type E fractures. Five patients with type 3 open fractures had fair or poor results. Thirteen patients (54%) had at least one complication. CONCLUSION: Patients with type C, D, or E fractures and those with greater skeletal injury scores are more likely to have fair or poor results due to the open nature of the fracture and to increased involvement of the knee joint. Although there is not an ideal method, rigid internal fixation seems to be more appropriate in fractures other than type 3 open tibia fractures.

Adolescent↗

PubMed2002

Human tibia bone marrow blood perfusion by non-invasive near infrared spectroscopy: a new tool for studies on microgravity.

Human tibia bone marrow (BM) and tibialis anterior muscle (TA) perfusion index (PI) was assessed non-invasively by near infrared spectroscopy. A decrease in the postis-chaemic reperfusion capability of the human tibia BM and TA muscle was observed for increasing age i.e., PI increases linearly as a function of age, starting from 30 years, both for BM (0.062 %/year, from -4.185 to -0.967 %/s) and TA muscle (0.046 %/year, from -5.760 to -3.883 %/s). The results define a "normal" baseline and demonstrate the sensitivity of the method to PI changes. The present technique should allow one to investigate physio-pathological effects induced by microgravity on tibia BM blood perfusion.

Journal Article↗

PubMed2004

Minimally invasive percutaneous plate osteosynthesis of fractures of the distal tibia.

Fractures of the distal tibia are notoriously difficult to treat, and traditional methods of fixation are often fraught with soft-tissue complications. With recent emphasis on meticulous handling and preservation of the soft-tissue envelope, minimally invasive percutaneous plate osteosynthesis has become a safe and reliable method of treating these fractures. This technique involves conventional open reduction and internal fixation of the fibula and spanning external fixation of the tibia until the soft-tissue swelling subsides. Subsequently, limited open reduction and internal fixation of displaced articular fragments is performed through small incisions based on CT evaluation. This is followed by minimally invasive percutaneous plate osteosynthesis of the tibia, in which the plafond is attached to the tibial shaft using a variety of commercially available plates.

Bone Plates↗

PubMed2004

[Comparison of internal fixation treatment of tibia intercondylar eminence fracture between absorbable screw and metallic screw].

OBJECTIVE: To compare advantage and disadvantage of internal fixation method for tibia intercondylar eminence fracture between absorbable screw and metallic screw. METHODS: From 1996 to 2002, 200 patients with fracture of tibia intercondylar eminence were divided into group A (with absorbable screw, n = 120) and group B (with metallic screw, n = 80). And the biological compatibility, biomechanics, bone union and complications were compared between two groups. RESULTS: There were no obvious differences in operating time and circumstance of recovery position between two groups. Group A was obviously better than group B in biological compatibility, biomechanics, bone union, joint function recovery. The average healing time of group A was three months, that of group B was three and half months. The good rates of joint function in two groups were 98.0% and 95.0% respectively. The occurrence rates of wound arthritis were 1.7% and 3.7%. There was significant difference between them (P < 0.01). CONCLUSION: Absorbable screw is a more ideal material of internal fixation to treat tibia intercondylar eminence fracture.

Absorbable Implants↗