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PubMed2001

Individual variability in human tibia lead concentration.

Our aims in this study were to determine proximal-distal variability in adult human tibia lead concentration via electrothermal atomization atomic absorption spectrometry (ETAAS) and to determine whether there were any differences between core and surface tibia lead concentrations. We analyzed duplicate core and surface tibia samples for lead at multiple proximal-distal sections on 10 adult human cadaver legs. Dried bone samples were digested in nitric acid using microwave-assisted heating, and lead content was determined by ETAAS with Zeeman background correction. Lead concentrations in nine tibiae (one tibia was excluded because some of the data were compromised) ranged from 3.1 to 27.9 microg lead/g of dry bone. Both core and surface tibia lead concentrations were lower at the proximal and distal ends of the tibia. Surface tibia lead was approximately 5 microg/g greater than core tibia lead in six tibiae with relatively low lead concentration, and 8 microg/g greater in three tibiae with relatively high lead concentration. The difference between core and surface tibia lead was independent of proximal-distal tibia location. We conclude that these nine human tibiae showed a greater surface tibia lead concentration than core tibia lead concentration. This observation has consequences for the noninvasive measurement of tibia lead via K-shell and L-shell X-ray fluorescence.

Cadaver↗
PubMed1991

Research note: current methods used in determination and evaluation of tibia strength: a correlation study involving birds fed various levels of cholecalciferol.

Tibiae were removed from 300 75-wk-old laying hens for tibia strength analysis using two methods, direct photon absorptiometry and tibia breaking strength. Left tibiae with flesh intact were used for bone density determination with direct photon absorptiometry. Right tibiae were cleaned and dried for determination of tibia weight and tibia breaking strength. Partial correlation coefficients were estimated among bone density, tibia breaking strength, tibia weight, and body weight. A significant correlation was observed between tibia breaking strength and bone density measurements (r = .66, P less than or equal to .0001). Tibia weight and tibia breaking strength were also significantly correlated (r = .62, P less than or equal to .0001), as well as bone weight and bone density (r = .71, P less than or equal to .0001). Tibia weight and BW were also significantly correlated (r = .66, P less than or equal to .0001), necessitating covariance adjustment for BW. Bone densitometry measurements are less variable than tibia breaking strength measurements, and bone densitometry does not require cleaning bones of flesh before measurement.

Absorptiometry, Photon↗
PubMedDate not supplied

An in vitro biomechanical investigation of the mechanical properties of dynamic compression plated osteotomized adult equine tibiae.

OBJECTIVE: To determine the monotonic mechanical properties of osteotomized adult equine tibiae stabilized with two dynamic compression plates (DCP) and to compare the mechanical properties with those of intact tibiae and in vivo loads. STUDY DESIGN: The compressive, bending, and torsional mechanical properties of plated and intact tibiae were assessed in vitro. ANIMALS OR SAMPLE POPULATION: Twelve pairs of adult equine tibiae. METHODS: Tibiae were loaded in axial compression, craniocaudal 3-point bending, or torsion in external rotation in a single cycle to failure. Mechanical properties were determined from load-displacement data. RESULTS: Compared to intact tibiae, the mean yield load, failure load and stiffness of plated tibiae were significantly lower (P < .05) (compression and torsion); and the mean yield and failure bending moments, and bending stiffness, of the plated tibiae were lower (P < .075 for yield), or significantly lower, respectively. The mean compression and bending yield loads for plated tibiae were greater than in vivo loads. The mean torsional yield load for plated tibiae approximated the torsional load determined for the adult horse at a walk. CONCLUSIONS: Simple, anatomically reduced, DCP plated tibiae should have adequate strength to withstand immediate, postoperative in vivo compressive loads and bending moments placed on the tibia in vivo during immediate postoperative activities, however, may not have adequate torsional strength during immediate postoperative weight-bearing at a walk. CLINICAL RELEVANCE: Additional supportive methods, to decrease torsional loads, may be beneficial in maintaining stability of plate repaired tibiae during recovery from anesthesia and postoperative healing.

Animals↗
PubMed2004

Comparison of metal concentrations in rat tibia tissues with various metallic implants.

To compare metal concentrations in tibia tissues with various metallic implants, SUS316L stainless steel, Co-Cr-Mo casting alloy, and Ti-6Al-4V and V-free Ti-15Zr-4Nb-4Ta alloys were implanted into the rat tibia for up to 48 weeks. After the implant was removed from the tibia by decalcification, the tibia tissues near the implant were lyophilized. Then the concentrations of metals in the tibia tissues by microwave acid digestion were determined by inductively coupled plasma-mass spectrometry. Fe concentrations were determined by graphite-furnace atomic absorption spectrometry. The Fe concentration in the tibia tissues with the SUS316L implant was relatively high, and it rapidly increased up to 12 weeks and then decreased thereafter. On the other hand, the Co concentration in the tibia tissues with the Co-Cr-Mo implant was lower, and it increased up to 24 weeks and slightly decreased at 48 weeks. The Ni concentration in the tibia tissues with the SUS316L implant increased up to 6 weeks and then gradually decreased thereafter. The Cr concentration tended to be higher than the Co concentration. This Cr concentration linearly increased up to 12 weeks and then decreased toward 48 weeks in the tibia tissues with the SUS316L or Co-Cr-Mo implant. Minute quantities of Ti, Al and V in the tibia tissues with the Ti-6Al-4V implant were found. The Ti concentration in the tibia tissues with the Ti-15Zr-4Nb-4Ta implant was lower than that in the tibia tissues with the Ti-6Al-4V implant. The Zr, Nb and Ta concentrations were also very low. The Ti-15Zr-4Nb-4Ta alloy with its low metal release in vivo is considered advantageous for long-term implants.

Animals↗
PubMedDate not supplied

Extraosseous blood supply of the tibia and the effects of different plating techniques: a human cadaveric study.

OBJECTIVE: To describe the extraosseous blood supply of the tibia and how the blood supply of the distal tibia is influenced by different plating techniques. DESIGN: Microdissection of cadaveric adult hip disarticulation specimens following sequential arterial injections of india ink and Ward's Blue Latex was performed. Readily identifiable arterioles measured approximately 0.5 mm in diameter. Their artery of origin was identified, and their position along the medial, lateral, and posterior aspects of the tibia was documented relative to the tibial plafond. Additionally, six matched pairs of limbs were used to assess the effects of different plating techniques on the extraosseous blood supply along the medial aspect of the distal tibia. SETTING: University anatomy laboratory. PATIENTS/PARTICIPANTS: Nine matched pairs ( = 18) of randomly obtained, adult cadaveric hip disarticulation specimens. INTERVENTION: India ink followed by Ward's Blue Latex was injected into the superficial femoral artery at the level of the inguinal crease after cleansing of the arterial system. The skin, subcutaneous tissue, and muscles were dissected from the leg, exposing the arterial system and the extraosseous vessels of the tibia. MEAN OUTCOME MEASUREMENTS: The extraosseous blood supply of each aspect of the tibial diaphysis was determined. Each extraosseous arteriole was identified, and the locations of each documented relative to the tibial plafond. Changes in the filling of these vessels along the medial aspect of the distal tibia were documented in a separate group of specimens ( = 12), which had undergone two different plating techniques. RESULTS: The proximal metaphysis of the tibia was found to have a rich extraosseous blood supply provided primarily from vessels from the popliteal artery, the anterior tibial artery (ATA) laterally, and the posterior tibial artery (PTA) medially. In comparison, the tibial diaphysis was found to have relatively few extraosseous vessels and a considerably hypovascular region, posteriorly. Branches of the ATA were found to supply the posterior aspect of the diaphysis with these branches passing through the interosseous membrane. The diaphysis also received a variable contribution from the PTA. The lateral aspect of the diaphysis was supplied by branches of the ATA. An anastomotic network of arteries from the ATA and PTA formed the rich extraosseous blood supply of the medial distal aspect of the tibia. Open plating of the medial aspect of the distal tibia caused a statistically significant ( < 0.05) greater disruption of the extraosseous blood supply of the metaphyseal region than did percutaneously applied plates. In each specimen, open plating prevented filling of each periosteal vessel in the region as opposed to percutaneous plates, which permitted filling of the extraosseous vessels up to the edge of the plate. CONCLUSIONS: The proximal and distal metaphyseal areas of the tibia have a rich extraosseous blood supply provided primarily by branches of the ATA and the PTA. Open plating of the medial aspect of the distal tibia caused a greater disruption of this extraosseous blood supply than did percutaneously applied plates. Disruption of these extraosseous vessels following fracture and subsequent operative stabilization may slow healing and increase the risk of delayed union and nonunion. These findings support current efforts to develop less invasive methods and implants for operative stabilization of distal tibia fractures.

Adult↗
PubMed2006

The effect of ankle rotation on cutting of the tibia in total knee arthroplasty.

BACKGROUND: Extramedullary alignment guides are commonly used to prepare the tibia during total knee arthroplasty. One disadvantage is that the guide is easily affected by the position of the ankle joint. The tibia may have a rotational mismatch between its proximal and distal ends. We hypothesized that a rotational mismatch might cause incorrect positioning of an extramedullary alignment guide and evaluated such a mismatch on the predicted postoperative coronal alignment of the tibia. METHODS: Fifty-three osteoarthritic knees with varus deformity in fifty-one patients were evaluated with use of computerized tomography scans before total knee arthroplasty. We defined one anteroposterior axis of the ankle joint and five different anteroposterior axes of the proximal aspect of the tibia using three-dimensional bone models from the computerized tomography data. We measured the rotational angle between the anteroposterior axis of the ankle joint and the proximal part of the tibia. The distal end of the extramedullary guide was placed in front of the center of the ankle joint (on the line of the extended anteroposterior axis of the ankle joint), and the proximal end was placed on the line of the extended anteroposterior axis of the proximal part of the tibia. We established spatial coordinates to evaluate the effect of the rotational angle on the predicted postoperative coronal alignment of the tibia and calculated the presumed tibial coronal alignment. RESULTS: The rotational angle was positive (3.6 degrees to 19.7 degrees) for all of the anteroposterior axes of the proximal aspect of the tibia, indicating that the ankle joint was externally rotated relative to the proximal part of the tibia. The predicted tibial coronal alignment was varus (0.5 degrees to 5.1 degrees) for all of the anteroposterior axes of the proximal part of the tibia. CONCLUSIONS: When an extramedullary alignment guide is used to prepare the tibia in total knee arthroplasty, varus alignment of the tibial component can occur because of a rotational mismatch between the proximal part of the tibia and the ankle joint.

Aged↗
PubMed1985

Critical periods during development as assessed by thallium-induced inhibition of growth of embryonic chick tibiae in vitro.

In ovo application of thallium sulfate has been shown to produce a characteristic shortening and angulation of the tibia of the embryonic chick. The critical period for susceptibility to thallium-induced inhibition of tibial growth ends at 8 2/3 days of incubation, a time when the growth rate of the embryo declines by 55%. The aim of the present study was to expose tibiae to thallium in vitro to determine whether this response was intrinsic to the tibia. A 4-hour exposure to 400 micrograms thallium was found to be most effective. Growth of tibiae from 8-day-old embryos was inhibited, growth of tibiae from 9-day-old embryos was not, and the response of tibiae isolated from embryos of 8 2/3 days of incubation was intermediate. Therefore, the response of the tibia to thallium represents an intrinsic property and is not secondary to inhibited nerve growth as has been suggested. The critical period and its termination is also an intrinsic property of the tibia. Tibiae were exposed to thallium for 4 hours at various times after the tibiae had been established in vitro. Susceptibility to growth inhibition was shown to decline as tibiae developed beyond the critical period, a decline that could be correlated with a declining growth rate. Emphasis is placed upon critical events during development as a more useful concept than critical periods for explaining susceptibility to teratogens.

Age Factors↗
PubMed2004

Speed of sound in bone at the tibia: is it related to lower limb bone mineral density in spinal-cord-injured individuals?

STUDY DESIGN: A cross-sectional study evaluating BMD at the hip and tibia, and SOS at the radius and mid-tibia in individuals with spinal cord injury (SCI) and a subgroup of non-SCI individuals. OBJECTIVES: To investigate the speed of sound (SOS) in bone in relation to bone mineral density (BMD). SETTING: Kinesiology Department, McMaster University, Ontario, Canada. METHODS: In 14 individuals with SCI and 10 non-SCI individuals, proximal femur and tibia BMD were measured using dual energy X-ray absorptiometry, and radius and tibia SOS were measured with an ultrasonometer. T-scores were calculated using healthy reference databases. Inter-relationships between measurement techniques were determined using Pearson's correlation coefficients. P-values less than 0.05 were considered statistically significant. RESULTS: : The average ages of the SCI and non-SCI groups were 33+/-9 and 27+/-6 years, respectively. Lesion level ranged from C4 to T12 and average time postinjury was 12 years, with a range of 1.6-25 years. Using the WHO criteria for osteoporosis, nine of 14 SCI subjects were osteoporotic at the hip, with the remainder in the osteopenic range. Tibia SOS T-scores were in the osteoporotic range for one subject with SCI, and two were in the osteopenic range. Among non-SCI individuals, one male had a tibia SOS T-score of -1.4, all others were within the normal range. Hip BMD and tibia SOS were significantly correlated (r=0.46, P<0.01). Hip BMD and tibia BMD were more strongly correlated (r=0.80, P<0.0005). Tibia BMD was not significantly correlated with SOS at the tibia (r=0.35, P=0.09). Radius SOS T-scores were positive and not significantly correlated with any lower limb variable. CONCLUSION: Lower-limb bone mass is reduced in spinal cord-injured individuals, but SOS at the mid-tibia is not. It remains to be determined whether ultrasound measurements can predict fracture in the SCI population.

Absorptiometry, Photon↗
PubMed2001

The effect of measurement location on tibia lead XRF measurement results and uncertainty.

The aims of this study were to determine whether the location on the tibia measured by 109Cd-based K-shell x-ray fluorescence (XRF) affected the measurement result and its uncertainty, and whether higher tibia lead levels at the extremities of the tibia and/or inhomogeneity in the distribution of lead in the tibia could be inferred therefrom. Replicate XRF measurements were performed at multiple locations on ten adult cadaver intact legs and on nine bare tibiae dissected from them. Mean lead levels in the bare tibiae ranged from 16 to 48 microg Pb per g of bone mineral. Bare tibia measurements showed that both the XRF result and its uncertainty increased towards the proximal and distal ends of the tibia. The XRF result decreased away from the medial-lateral mid-point of the tibia, but XRF uncertainty was not significantly affected. Intact leg measurements showed no effect of proximal distal location on XRF result but did show an effect on XRF uncertainty. We conclude that the XRF method used can determine the differences in bone lead level resulting from the more trabecular composition at the ends of the tibia, and we present limited evidence for localized regions of low tibia lead level.

Bone and Bones↗
PubMedDate not supplied

Transfixion wire positioning within the bone: an option to control proximal tibia external fixation stiffness.

PURPOSE: The greatest angle that can be formed by the crossing wires at the proximal tibia level without altering safe corridors approaches only 60 degrees. Consequently, the wires are positioned more in the coronal than the sagittal plane. Looking for an increase in sagittal bending stiffness, we evaluated different wire positioning within the proximal tibia and their effect on the stiffness of external fixation of proximal tibia. STUDY DESIGN: A fiberglass composite tibia fixed into an idealized ring external frame was tested with a servohydraulic test frame. Load-deformation behavior was compared among the different wire positioning within the proximal tibia under identical conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. Stiffness values were calculated from the load-deformation and the torque-angle curves. RESULTS: The sample with 3 wires positioned within the bone-2 wires crossed 1 cm posteriorly from the center of the tibia and the third wire placed in coronal plane 1 cm anteriorly from the center of the tibia-was significantly (P < 0.05) stiffer in posterior, posteromedial, and torsional loading configurations compared with all other wire positions within the bone. CONCLUSIONS: This new wire positioning within the proximal tibia-2 wires crossed 1 cm posteriorly from the center of the tibia and the third wire placed in coronal plane 1 cm anteriorly from the center of the tibia-increased overall stiffness of external fixation, predominantly in sagittal plane. CLINICAL RELEVANCE: This work provides a rationale to control proximal tibia external fixation stiffness in sagittal plane.

Bone Wires↗
PubMed2005

Discriminant function sexing of fragmentary and complete tibiae from medieval Croatian sites.

Previous studies have demonstrated that populations differ from each other in size and proportion and that these differences can affect metric assessment of sex. This paper establishes standards for determining sex from fragmentary and complete tibiae in the medieval Croatian population. The sample is composed of 180 tibiae (96 males and 84 females) from six medieval archaeological sites in Croatia. Three of the sites were located in continental Croatia, three on the eastern Adriatic coast and its immediate hinterland. Six tibial dimensions were measured: (1) length of the tibia; (2) maximum epiphyseal breadth of the proximal tibia; (3) maximum epiphyseal breadth of the distal tibia; (4) maximum diameter of the tibia at the nutritient foramen; (5) transverse diameter of the tibia at the nutritient foramen; and (6) circumference of the tibia at the nutritient foramen. Unifactorial and multifactorial analyses were performed on the collected data. Six discriminant functions were generated, one using six variables, two using two variables, and three employing one variable. Results show that complete tibiae can be sexed with 92.2% accuracy. Slightly lower accuracies (91.7 and 87.8%) were achieved using a combination of two variables, while functions employing one variable were accurate from 85.6 to 81.7%. The results of this study show that the medieval Croatian tibia is a good skeletal component for determining sex. Standardized coefficients of the discriminant functions generated in this study support the results of previous studies that found that breadth dimensions provide better separation of the sexes than length.

Anthropometry↗
PubMed2002

Measurements of lead in human tibiae. A comparison between K-shell x-ray fluorescence and electrothermal atomic absorption spectrometry.

The aim of this study was to validate 109Cd-based K-shell x-ray fluorescence measurements against atomic absorption spectrometry (AAS) measurements of core and surface tibia lead. The lead content of nine adult human cadaver tibiae was measured using 109Cd-based K-shell x-ray fluorescence (XRF) spectrometry and the results compared to measurements obtained using electrothermal atomization atomic absorption spectrometry following acid digestion. Each tibia was divided into nine cross-sectional segments, which were further separated into tibia core and surface samples for the AAS analytical measurements. Proximal-distal variability in tibia lead concentration as determined by AAS was previously described for both surface and core segments and was found to decrease towards the ends of the tibia, in contrast to XRF in which lead was found to increase towards the tibia ends. The effect of this contrasting behaviour on the agreement between XRF and AAS measurements was examined. Lead concentrations determined by AAS ranged from 3 to 19 microg of lead per gram of dry weight bone (microg g(-1)) for tibia core and from 5 to 32 microg g(-1) for tibia surface. Lead concentrations determined by XRF ranged from 2 to 35 microg g(-1) dry weight. No statistically significant difference was found between mean XRF-measured concentrations and mean surface lead concentrations measured by AAS, but XRF significantly overestimated tibia core lead concentrations by between 5 and 8 microg g(-1).

Cadmium Radioisotopes↗
PubMed2006

Femoral deformity in tibia vara.

BACKGROUND: Previous studies have suggested that compensatory valgus deformity of the femur is common in patients with tibia vara, or Blount disease. The availability and routine use of standing long-cassette radiographs of the lower extremities to assess angular deformities has allowed quantitative evaluation of this hypothesis. METHODS: The cases of all patients with tibia vara, two years of age or older, seen at our institution prior to treatment, over a thirteen-year period, were reviewed. Seventy-three patients with a total of 109 involved lower limbs were identified and were classified as having either infantile tibia vara (thirty-seven patients with fifty-six involved limbs) or late-onset tibia vara (thirty-six patients with fifty-three involved limbs). Standardized standing radiographs of the lower extremity were examined to assess the deformity at the distal part of the femur and the proximal part of the tibia by measuring the lateral distal femoral angle and the medial proximal tibial angle. RESULTS: The distal part of the femur in the children with infantile tibia vara either was normal or had mild varus deformity, with a mean lateral distal femoral angle of 97 degrees (range, 82 degrees to 129 degrees). The mean medial proximal tibial angle in these children was 72 degrees (range, 32 degrees to 84 degrees). Older children with infantile tibia vara were noted to have little distal femoral deformity, with no more than 4 degrees of valgus compared with either normal values or the contralateral, normal limb. Children with late-onset tibia vara had a mean lateral distal femoral angle of 93 degrees (range, 82 degrees to 110 degrees) and a mean medial proximal tibial angle of 73 degrees (range, 52 degrees to 84 degrees). On the average, the varus deformity of the distal part of the femur constituted 30% (6 degrees of 20 degrees) of the genu varum deformity in these patients. CONCLUSIONS: Patients with infantile tibia vara most commonly had normal alignment of the distal parts of the femora; substantial valgus deformity was not observed. Distal femoral varus constituted a substantial portion of the genu varum in children with late-onset disease. When correction of late-onset tibia vara is planned, the surgeon should be aware of the possibility that distal femoral varus is a substantial component of the deformity.

Adolescent↗
PubMed1983

In vitro effects of external fixation on intact and osteotomized tibiae. A biomechanical study.

In order to study the in vitro mechanical effects of external fixation on intact and osteotomized bone, human and rabbit tibiae were tested in three-point bending in an Instron testing machine. Intact tibiae were loaded in the elastic range before and after application of an external fixation device. In the human specimens the Vidal-Adrey double frame was used, and in the rabbit specimens the external mini-fixation. The bone deformation in the anteroposterior direction was measured with a linear voltage differential transformer. After application of external fixation a median bone elastic stiffness of 110.2 per cent in human tibiae and of 106.1 per cent in rabbit tibiae was found, in relation to the stiffness of intact tibiae without external fixation. The stiffness increase was significant in human specimens, but not significant in rabbit specimens. In osteotomized human tibiae fixed with the Vidal-Adrey double frame a median stiffness of 8.5 per cent of the stiffness of intact bones was found when compression was not applied, compared to 19.9 per cent when compression was applied. In rabbit tibiae a median stiffness of osteotomized bones with external mini-fixation was 8.9 per cent of the stiffness of intact bones. There was a good agreement between the results in rabbit tibiae with the mini-fixation and human tibiae with external fixation without compression. The external mini-fixation thus seems to be a suitable model for the study of bone healing in rabbit tibiae.

Aged↗
PubMed1991

Effect of dietary sodium zeolite A and graded levels of calcium on growth, plasma, and tibia characteristics of chicks.

Sodium zeolite A (SZA), a synthetic sodium aluminosilicate having high ion-exchange capacity, has been shown to increase eggshell specific gravity in laying hens and to improve Ca utilization in chickens. A 4 x 2 factorial arrangement of treatments was used to investigate the effect of dietary Ca (.6, .8, 1.0, and 1.2%) and SZA (0 and .75%) on growth, plasma, and tibia characteristics of chicks from 5 to 15 days of age. Increasing dietary Ca linearly increased (P less than .05) Ca and alkaline phosphatase (AP) in plasma and increased tibia shearing force and percentage ash, Ca, and P in tibiae. However, dietary Ca linearly decreased (P less than .05) inorganic P and Mg in plasma and Mg and Mn in tibiae. Sodium zeolite A decreased (P less than .05) plasma P and AP and tibia Mg but increased (P less than .05) tibia Ca, Zn, Al, and Mn concentrations. Tibia ash and shearing force were increased in chicks fed SZA receiving inadequate dietary Ca, but they were decreased in chicks fed SZA and excess Ca (Ca by SZA interaction, P less than .05). Tibia density showed a similar trend, but the effect was not significant (Ca by SZA interaction, P less than .12). The addition of SZA enhanced tibia ash, density, and shearing force when dietary Ca was low; however, when added to diets containing 1.2% Ca, SZA reduced many bone mineralization indices with the exception of tibia Ca.

Aluminum↗
PubMed1989

Tibia vara. A critical review.

Since Blount's classic article was published in 1937, many authors have contributed to the knowledge of tibia vara. Tibia vara is characterized by an abrupt angulation of the tibia into varus in the proximal end. The term does not reveal the etiology of the anatomic deformity, which may be developmental, posttraumatic, or postinfectious. There are four types: (1) Infantile tibia vara (Blount's disease) is a developmental condition that manifests itself between the ages of one and four years. Roentgenographic findings are typical. (2) Adolescent tibia vara is caused by partial closure of the growth plate after trauma or infection between the ages of six and 13 years. (3) Late-onset tibia vara appears in obese black children between the ages of six and 15 years. The roentgenographic findings differ from those of the other types, but the histopathology is similar to infantile tibia vara. (4) Tibia vara may also be caused by focal fibrocartilaginous dysplasia. Eight cases in which there was an area of fibrocartilaginous dysplasia in the medial aspect of the tibia have been reported in the literature. Several problems have been encountered in the treatment of infantile tibia vara.

Bone Diseases, Developmental↗
PubMed2004

[The design and application of synchronized springy lengthening apparatus for the tibia and tendo calcaneus].

OBJECTIVE: To study the role of the synchronized springy lengthening apparatus for the tibia and calcaneal tendon designed by the author in preventing the clubfoot of secondary to the Ilizarov tibia lengthening. METHODS: Based on the Ilizarov tibia lengthening apparatus, a special synchronized springy lengthening apparatus for the tibia and calcaneal tendon was designed. The tibial was made of distal and proximal 2 rings respectively and 4 threaded rods, and the calcaneal was made of a half ring, 2 hinges and a threaded rod with spring. The half ring was fixed to the calcaneus by 2 crossed wires. The fracture tibia and fibula, ankle joint, talocalcaneal joint were attached to the apparatus. At the same time of tibia lengthening, the soft tissue was simultaneously stretched, the ankle joint could move, and the leg could bear weight. If the clubfoot angle was larger, the percutaneous fasciotomy of calcaneal tendon was performed; if the angle was less than 20 degrees, the pes deformities were corrected only by the stretch of calcaneal tendon. RESULTS: Seventy-seven patients' tibia were lengthened averagely 4.6 cm, with an average speed of 0.7 mm/d. The healing made tibia lengthened, and the index was 1.35 months/cm. There were not the secondary varus and valgus deformities and clubfoot in all the patients. The clubfoot with 100-400 angle of the 16 patients were corrected after tibia lengthening. CONCLUSIONS: The new apparatus coincides with the biomechanical principle and can effectively prevent the secondary deformities of foot such as clubfoot, talipes varus and valgus after tibia lengthening procedure.

Adolescent↗
PubMed2006

Does a tensioning device pinned to the tibia improve knee anterior-posterior load-displacement compared to manual tensioning of the graft following anterior cruciate ligament reconstruction? A cadaveric study of two tibial fixation devices.

Devices that are pinned to the tibia to tension an anterior cruciate ligament (ACL) graft produce joint reaction loads that in turn can affect the maintenance of graft initial tension after tibial fixation and hence knee anterior-posterior (AP) load-displacement. However, the effect of these devices on AP load-displacement is unknown. Our objectives were to determine whether tensioning by device versus tensioning by hand causes differences in AP load-displacement and intraarticular graft tension for two commonly used tibial fixation devices: a bioresorbable interference screw and a WasherLoc. AP load-displacement and intraarticular graft tension were measured in 20 cadaveric knees using a custom arthrometer. An initial tension of 110 N was applied to a double-looped tendon graft with the knee at extension using a tensioning device pinned to the tibia and a simulated method of tensioning by hand. After inserting the tibial fixation device, the 134 N anterior limit (i.e., anterior position of the tibia with respect to the femur with a 134 N anterior force applied to the tibia) and 0 N posterior limit (i.e., AP position of the tibia relative to the femur with a 0 N force applied to the tibia) were measured with the knee in 25 degrees flexion. Intraarticular graft tension was measured at extension. These limits and intraarticular graft tension were also measured after cyclically loading the knee 300 times. Compared to a simulated method of tensioning by hand, tensioning with a device pinned to the tibia did not decrease the 134 N anterior limit and did not cause posterior tibial translation. However, intraarticular graft tension was maintained better with a tensioning device pinned to the tibia for the Washerloc, but not the interference screw. For two commonly used tibial fixation devices, a tensioning device pinned to the tibia does not improve AP load-displacement at 25 degrees flexion over tensioning by hand when the graft is tensioned at full extension, but does improve the maintenance of intraarticular graft tension for the Washerloc.

Absorbable Implants↗