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Motion of the ankle in a simulated supination-external rotation fracture model.

UNLABELLED: An experimental study was undertaken with use of axially loaded, unconstrained cadaver ankles to determine the motion patterns seen with progressive stages of the supination-external rotation type of fracture. As described by Lauge-Hansen, these fractures were modeled by transection of the anterior aspect of the capsule and the anterior tibiofibular ligament (stage I), followed by oblique fibular osteotomy ending at the level of the ankle joint (stage II), transection of the posterior aspect of the capsule (stage III), and sequential sectioning of the superficial and deep fibers of the deltoid ligament (stage IV). Thirteen specimens were tested on an apparatus that allowed for controlled loading while the ankle was passed through a physiological range of dorsiflexion and plantar flexion. The ankles were unconstrained about the axial (internal and external rotation) and coronal (varus and valgus angulation) axes. Measurements were made throughout the range of motion in these axes in order to define the kinematic behavior. In the intact specimens, maximum plantar flexion was associated with a mean (and standard deviation) of 1.9 +/- 4.12 degrees of internal rotation of the talus and maximum dorsiflexion, with a mean of 7.2 +/- 3.88 degrees of external rotation. Varus angulation increased slightly with plantar flexion compared with the value in dorsiflexion (2.4 +/- 2.40 compared with 0.3 +/- 1.96 degrees). Internal and external rotation was not affected by fibular osteotomy or by transection of the superficial fibers of the deltoid ligament. Transection of the deep fibers of the deltoid ligament caused a significant (p < 0.02) increase in external rotation of the talus at maximum plantar flexion; this was corrected incompletely by insertion of an anatomical fibular plate. With the numbers available for study, we could not show that varus or valgus angulation was significantly affected by any combination of sectioning of the deltoid ligament and fibular osteotomy. These experiments were repeated with the addition of fixation of the subtalar joint with a talocalcaneal screw. With the number of specimens available, we could detect no significant difference, with respect to axial rotation, due to fixation of the subtalar joint. However, along the coronal axis, increased valgus angulation (p < 0.02) was seen during plantar flexion when either the deep or the superficial fibers of the deltoid ligament had been cut. CLINICAL SIGNIFICANCE: These results indicate that stability of the loaded ankle is primarily due to the deltoid ligament, which exerts a restraining influence on external rotation of the talus. Complete fibular osteotomy did not cause abnormal motion of the ankle in the absence of a medial injury. In the presence of a complete injury, lateral reconstruction only partially restored the mechanical integrity of the ankle. The results provide justification for the non-operative treatment of isolated fractures of the lateral malleolus. The data also suggest that a lateral fracture associated with a major injury of the deltoid ligament should be treated with anatomical lateral fixation followed by immobilization without early motion, to allow adequate healing of the deltoid ligament at its resting length.

Aged↗

Subluxation of the talocalcaneal joint in adults who have symptomatic flatfoot.

BACKGROUND: When flatfoot is acquired during adulthood, the shape of the foot changes. In addition to a decreased arch, there may be valgus angulation of the hindfoot or abduction of the forefoot, or both. However, there is little objective information to provide a better understanding of the anatomical or morphological changes that occur in acquired adult flatfoot. We wondered if such an understanding of the three-dimensional anatomy might shed light on the pathway by which these changes occur. We designed this study to measure the three-dimensional position of the talocalcaneal joint in patients who have painful flatfoot. METHODS: Computed tomography scans of the feet of eight patients who had symptomatic flatfoot were used to construct a model of the talocalcaneal articulation. The scans were performed on a custom loading frame developed to simulate weight-bearing with the foot in a neutral position while a seventy-five-newton axial compressive load was applied. The digital data from the scans were used to make three-dimensional computer models of the articular surfaces of the talus and calcaneus of each foot. These models then were used to calculate the percentage of the articular surface that was in contact and, conversely, the percentage that was subluxated. Two surfaces were modeled for each bone; the posterior facet formed one surface, and the anterior and middle facets were combined to form the second surface. The data were compared, with use of Mann-Whitney nonparametric U analysis, with those derived from scans of the feet of four patients without a deformity of the hindfoot who served as controls. RESULTS: A mean (and standard deviation) of 68+/-9 percent of the posterior facet of the calcaneus was in contact with the talus in the patients who had flatfoot compared with 92+/-2 percent in the controls, and a mean of 51+/-23 percent of the anterior and middle facets of the calcaneus was in contact with the talus in the patients who had flatfoot compared with 95+/-6 percent in the controls. These differences were significant (p = 0.0066 for both). CONCLUSIONS: Marked subluxation of the talocalcaneal joint occurs in some patients who have symptomatic planoabductovalgus deformity.

Adult↗

[Influence of the posterior tibial tendon on the medial arch of the foot: an in vitro kinetic and kinematic study].

INTRODUCTION: The respective contributions of the active and passive structures of the foot to the stability of the medical arch were investigated using an in vitro kinetic and kinematic model. The effect of the tibialis posterior tendon on foot and ankle movements, and plantar pressure distribution of the foot were tested in a cadaveric human foot. METHOD: The stance phase from heel-contact to toe-off of normal walking gait and after tibialis posterior tendon rupture was simulated in eight roentenographically normal human feet (age 66 +/- 19 years, males). Ground reaction force and tibial inclination was simulated by means of a tilting angle and force-controlled translation stage. Plantar pressure was measured using a pressure-measuring platform. The force developed by the flexors and extensor muscles of the foot were simulated via cables attached to 7 force-controlled hydraulic cylinders. Tibial rotation was produced by an electric servo-motor, and foot movements measured with an ultrasonic analysis system. RESULTS: The model was verified against the plantar distribution and kinematics of healthy subjects measured during normal gait. Tibialis posterior deficit did not result in any detectable changes in pressure or force-time integral in the medial regions of the foot--a common sign of flat foot (pressure: midfoot 0.2 < or = 0.9; medial forefoot 0.5 < or = p < or = 0.9; hallux 0.5 < or = p < or = 0.9; force-time integral: midfoot p = 0-871; medial forefoot p = 0.632; hallux p = 0.068). Only small tendential changes in the kinematics of the talus and calcaneus were observed in dorsiflexion (0-58 sec; talus 0.1 < or = p < or = 0.6; calcaneus 0.4 < or = p < or = 0.06) and eversion (talus: 0-60 sec. 0.1 < or = p < or = 0.6; calcaneus: 37-60 sec. 0.2 < or = p < or = 0.7). CONCLUSION: The results of this in vitro study show that defective tibialis posterior alone does not produce significant changes in the kinetics or kinematics of the stance phase of normal gait. This suggests that the development of flat foot observed in degeneration of the tibialis posterior tendon occurs only after fatigue of the passive structures of the foot.

Adult↗

A dynamic study of the ankle-foot complex.

A kinematic study of the ankle-foot complex in 19 healthy volunteers was performed using computerized radiocinematography. We found that the instant centers of rotation of the ankle joint fell closely within the talus in the sagittal plane. When the ankle joint moved, the talus, the calcaneus and the navicular bone performed different excursions. Except for the movement in the sagittal plane, the calcaneus assumed eversion in dorsiflexion and inversion in plantar flexion when the ankle moved in an open kinematic chain (under non-weight-bearing conditions). In a closed kinetic chain movement (under weight-bearing conditions), the lower leg exhibited internal rotation, and the talus moved plantarward when the ankle was dorsiflexed. The internal rotation of the lower leg did not cause a slippery rotation of the foot on the surface, but rather it was converted into eversion of the calcaneus in the frontal plane.

Adolescent↗

[Malunited juvenile fractures in the foot region].

Between 1971 and 1990 we treated 121 juvenile patients up to 14 years of age with fractures of the ankle joint and foot in the department of trauma surgery at Hannover Medical School. A total of 128 fractures were treated in these patients, excluding toe fractures. The distribution of fractures as referred to the anatomical-functional planes was as follows: Tibia-talar joint 69; talus 8; calcaneus 6; Chopart joint 5; Lisfranc joint 4 and metatarsal area 36. Clinical and radiological follow-up investigations were possible a mean of 8.7 years post trauma for all talar and calcaneal fractures, for 7 out of 9 Chopart/Lisfranc injuries and for 7 out of 35 of metatarsal fractures. In the case of talus fractures our results suggest that it is to restore the original length of the talus bone (medial column); this is important to prevent collapse of the longitudinal arch with subsequent early arthritis. The rare cases of sustained intraarticular damage to calcaneal fractures should be treated as in adults, i.e. by open, anatomical reconstruction. In children, Chopart/Lisfranc 2 fracture dislocations only occur if high-energy trauma is present (runover trauma in 4 out of 9 cases). Optimal treatment again is comparable to that in adults: open, anatomical reduction with Kirschner-wires followed by temporary, tibio-tarsal transfixation; this is important since no compensatory mechanisms develop if a subluxation is present after reduction. Metatarsal fractures often occur along the first and fifth rays and have a good prognosis. Conservative treatment is justified, since, according to our results, even in intraarticular fractures of the metatarsal head good remodeling to fragments occurs.

Adolescent↗

[Congenital convexity of the feet. Anatomical study and practical conclusions].

The authors have studied the pathological anatomy of two congenital pes convex, (C.P.C) coming from an 8 days boy suffering of arthrogryposis. One of the feet has been dissected by stage whilst the other one has been operated on according to a procedure of correction of the deformities. The two feet combined an irreducible dislocation of the os naviculare on the neck of the talus, a calcaneo cuboïdeum subluxation, a moderate equinus of the hind foot, an important contracture of the extensor tendons and an elongation of the structural soft tissues of the sole. The main abnormalities of the talus and of the calcaneus involved the upper direction of the anterior articular facet, in relation to the dorsal dislocation of the os naviculare and the dorsal subluxation of the cuboïdeum. The subtalaris joint was little altered. The study of dissections and the clinical reports published connected with the observations of the authors confirm the pre-eminence of the transversal dislocation of the tarsus and of its irreducibility. On the other hand the abnormalities of the subtalar joint have been, probably over estimated. The sometimes important increase of talo calcaneal angle on A.P. radiographies may be explained by the incidence itself. The verticality of the talus is not a reliable feature of C.P.C. and the deformities of the fore foot are variable (pronation, supination). This study leads to a new definition of the C.P.C.: Congenital deformity of the foot with tarsi-transversa dislocation or subluxation involving mainly the talo-navicular joint. The criterious of diagnosis are debated and a logical surgical procedure of correction is suggested.

Ankle Joint↗

The modified Chopart's amputation.

A modified Chopart's amputation has been designed to overcome the complications of the traditional Chopart's amputation of plantar flexion and skin breakdown over the anterior talus and calcaneus. The modifications are: (1) contouring of the talus and calcaneus; (2) transfer of the anterior and posterior tibialis tendons and the extensor communis and hallucis to the neck of the talus and sustentaculum tali; (3) anterior advancement of the plantar flap; and (4) lengthening of the tendo Achillis. This procedure has been performed in a prospective manner on eight feet in six children. An average 3.5-year follow-up term has not revealed any complications. The modified Chopart's procedure appears to be a functional, useful amputation for children requiring foot ablation secondary to congenital malformations.

Amputation, Surgical↗

Reconstruction of malunited fractures of the lateral malleolus.

The cases of twenty-six patients who had a reconstructive surgical procedure for treatment of a malunion of a displaced fracture of the fibula were evaluated. In these patients, who had pain, swelling of the ankle, and stiffness at an average of six years after the injury, the malunions were classified radiographically as either occult (eighteen patients) or overt (eight patients). An occult malunion was one in which the talus remained in its normal position, but the lateral malleolus showed residual displacement, characterized by external rotation and shortening. In an overt malunion, there were similar changes in the lateral malleolus, but the talus was displaced. All of the patients were treated by osteotomy of the lateral malleolus to correct the external rotation and shortening, to reduce the lateral subluxation of the anterior aspect of the tibiofibular joint, and to restore the stability of the talus. At an average follow-up of seven years (range, six months to eleven years), twenty of the twenty-six patients were able to resume the preinjury level of activity; three had improvement in the ability to walk and in the level of functional activity, although they still had intermittent pain; and three had not benefited from the procedure.

Adolescent↗

Laterally comminuted fracture-dislocation of the ankle.

Laterally comminuted fracture-dislocations of the ankle are highly unstable injuries in which anatomical reduction of the talus and restoration of fibular length and rotation are difficult. To our knowledge, no descriptions of the fracture pattern of these injuries and the surgical technique for treating them are available, and surgical results with this fracture have been disappointing. Discontinuity of the fibula as a result of comminution makes accurate assessment of fibular length and rotation impossible if the fibula is reduced first. Anatomical stabilization of the talus beneath the tibia is achieved by reduction and fixation of the medial malleolus. The fibular malleolus is then anatomically positioned in the lateral articular facet of the talus and fixed in this position. The osseous discontinuity of the fibula is grafted with bone. Clinical and radiographic results of the technique were highly satisfactory after a mean length of follow-up of thirty-four months.

Adult↗

The key role of the lateral malleolus in displaced fractures of the ankle.

The reason why late degenerative arthritis developed in some patients who had sustained displaced bimalleolar fractures of the ankle was investigated. The roentgenograms indicated that incomplete reduction of the lateral malleolus and a residual talar tilt were present. When bimalleolar fractures were created in cadavera the talus could be anatomically repositioned only when the lateral malleolus was accurately reduced. Fifty-three patients with bimalleolar fractures were treated by anatomically fixing the lateral malleolus with a four-hole plate. There was an anatomical reduction of the talus and medial malleolus in each instance and there were no late cases of degenerative arthritis when these patients were followed for from six months to nine years. We concluded that the lateral malleolus is the key to the anatomical reduction of bimalleolar fractures, because the displacement of the talus faithfully followed that of the lateral malleolus.

Ankle↗

The hindfoot and its relation to rotational deformities of the forefoot.

The movements occurring at the various joints of the foot are complex, and since deformities can arise at each joint, classification of the deformities of the foot can be confusing. The position of the hindfoot can be conveniently described using the relationship of the long axis of the calcaneus to the long axis of the tibia. The position of the forefoot can then be related to that of the hindfoot. Rotation of the forefoot occurs as a result of relative movements of the talus and calcaneus and is a noticeable feature of the valgus or flat foot. Various types of valgus foot are recognized, e.g., calcaneovalgus, equinovalgus or "vertical talus," and so-called "postural" valgus. A variation is described in which the hindfoot is valgus by definition, when the patient is standing, but in which after correction the talus moves into an abnormally horizontal position relative to the calcaneus and the forefoot assumes a position of marked supination, almost appearing to stand on its lateral edge. This deformity has been observed in paralytic conditions and also in an idiopathic form. It may be correctable if detected early but if allowed to progress may result in a persistent deformity, producing discomfort and excessive shoe wear. In the late stage correction of the hindfoot may, if the rotational component is not recognized, result in an unacceptable forefoot position.

Child↗

Exostosis presenting as solitary loose body in the ankle of two children.

Two children, aged 5 and 11 years, presented clinically with ankle pain and a mobile bony hard lump in the ankle. Radiological examination revealed a large radio-opaque shadow in relation to the talus. Intraoperatively, a loose body was found. It resembled a detached exostosis with cartilaginous cap and was confirmed histologically as an osteochondroma. In the older child, there was a remnant stalk attached to the lateral surface of the talus. In the younger child, the exostosis probably came from the talus as the osteochondroma could not originate from the epiphyses that form the ankle mortise.

Ankle↗

[Too long antero-medial process of the calcaneus. A study of 59 cases in 37 children and adolescents].

PURPOSE OF THE STUDY: In 1983, we reported 5 cases of a type of tarsal abnormality which often went unrecognized in children and adolescents, the so-called "too long antero-medial process of the calcaneus" (TLAP). This report analyzes 59 such abnormalities observed in 37 children and adolescents. Treatment of the 48 symptomatic cases is presented. MATERIAL: A retrospective study was done on the files of all patients in whom oblique foot radiographs, CT scan or MRI of the foot showed an abnormal antero-medial process of the calcaneus. Of this group, patients were re-examined and radiographs of both feet (AP, lateral and oblique views) were obtained. METHODS: Gender, age at occurrence of symptoms, diagnosis and follow-up, patient complaints and successive treatment were assessed. Final clinical results were graded according to patient's complaints of pain and functional limitation as well as clinical evaluation of subtalar motion. RESULTS: Fifty-nine TLAPs have been found in 37 patients, 30 girls and 7 boys of 11.6 years on average at the first symptoms. Delay of diagnosis from onset of symptoms to final diagnosis averaged 2 years. First symptoms were so-called ankle sprains in 19 patients, ankle instability with tarsal pain in 17, pain and tarsal stiffness in 11, spastic flat foot in 1. In 11 patients, the abnormality was found on the opposite foot. In 2 patients, the TLAP was combined to a calcaneo-navicular bridge of the other foot. Eleven strapping managements resulted in 11 failures, 36 plaster immobilizations led to 12 good, 2 fair and 22 poor results; 25 resections gave 23 good, 1 fair and 1 poor result at a 4.6 years follow-up on average. DISCUSSION: In some people, the antero-medial process of the calcaneus is elongated and becomes interposed between the head of the talus and the cuboïd, far enough to cause impingement on the navicular. Because of the elongation, supination produces a "nutcracker" phenomenon with compression of the process between the talus and the cuboïd; this may result in a chondral injury of the talus head at its inferior and lateral part which faced the TLAP. Authors suggest that calcaneo-navicular coalition and TLAP represent a spectrum of types of errors in embryologie mesenchymal formation with lack of normal joint formation of the tarsal ossicles during fetal life. Immobilization treatment as primary management was particularly unsuccessful in the group with recurrent ankle sprains and persistent pain. Process resection proved a highly successful technique in management of those patients who failed to achieve good results with plaster immobilization. CONCLUSION: The "too long antero-medial process of the calcaneus" should be considered when assessing possible causes of recurrent ankle sprain or persistent tarsal pain in adolescents. An oblique X-ray is usually satisfactory for diagnosis. In patients who failed a conservative management, resection of the process produced good results and painless, supple feet.

Adolescent↗

A new pitheciin primate from the middle Miocene of Argentina.

We report here a new fossil primate from the middle Miocene of Argentina. The material consists of isolated teeth, mandibular fragments, and a talus. The fossils were collected in the Collón Cura formation at Cañadón del Tordillo in Neuquén Province. An age of 15.71 +/- 0.07 Ma has been reported for the Pilcaniyeu Ignimbrite, which lies just below the paleosols in which the fossils were found. This material is thus the youngest occurrence of fossil primates in Argentina (hitherto documented in the Santacrucian and older land mammal ages) but still is older than the middle Miocene platyrrhine primates from La Venta, Colombia, in particular the pitheciins Nuciruptor and Cebupithecia. The material is recognized as a new genus and species of Pitheciinae, Propithecia neuquenensis. The mesiodistally compressed, high-crowned incisors are specialized and similar to species in the tribe Pithecini and to the nonpitheciin Soriacebus (early Miocene, Patagonia). We rule out a phylogenetic relationship to the latter because of differences in molar morphology. Propithecia does, however, fit well into the pattern of pitheciin evolution, being more derived than the middle Miocene pitheciin Nuciruptor but not as much as another middle Miocene taxon, Cebupithecia. As such, this makes Propithecia the oldest taxon that can be confidently placed within this modern New World monkey subfamily. By analogy with the molar structures and diets of extant platyrrhines, Propithecia has a molar structure consistent with a variety of low-fiber diets ranging from fruit and gum to seeds. Its incisors suggest seed-eating in much the same way as extant pitheciins, like Pithecia. The talus resembles that of Callicebus, suggesting arboreal quadrupedal locomotion.

Animals↗

Blood vessels of the sinus tarsi and the sinus tarsi syndrome.

This study describes the arterial and venous blood vessels in the sinus tarsi of a series of nine anatomical specimens and in a traumatically amputated leg, studied by arteriography. The sinus tarsi artery was formed in all cases from anastomoses between various arteries of the lateral region of the foot. These usually included the anterior lateral malleolar, and proximal lateral tarsal arteries; in 70% there was a branch from the distal lateral tarsal artery, and in 30% a branch from the peroneal artery. In all cases, there were anastomoses within the sinus tarsi between the sinus tarsi artery and the canalis tarsi artery, derived from the posterior tibial artery. Whatever its origins, the sinus tarsi artery was the principal supplier of intrasinusal structures and of the talus. There was a large venous plexus in the sinus tarsi, which drained particularly the venous outflow from the talus and the anterior part of the capsule of the posterior talocalcaneal joint to the lateral and medial venous systems of the foot. Posttraumatic fibrotic changes in the wall and surrounding tissue of the veins, causing disturbance of venous outflow and increased intrasinusal pressure, are proposed by the authors as one possible factor in the pathogenesis of the sinus tarsi syndrome.

Arteries↗

Foot bones from Omo: implications for hominid evolution.

We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines).

Anatomy, Comparative↗

Predicting talocalcaneal joint orientations from talocalcaneal/talocrural joint orientations.

The purpose of this investigation was to determine the capacity of talocalcaneal/talocrural joint orientations to predict talocalcaneal (TC) joint orientations. A custom designed orientation-loading fixture was used to position the calcaneus and shank with six degrees of freedom, and to apply loads in three orthogonal directions. Three reference pins were rigidly mounted in the calcaneus, talus, and shank segments to provide position data in 243 test situations. Test data were fitted to statistical models using analysis of variance. The models were then used to determine the capacity to predict talus positions from shank positions, both with respect to the calcaneus. Results indicated large between and within specimen variation and was attributed to individual joint morphology. It was concluded that (a) eversion-inversion orientations of the TC/talocrural joint were not always accurate indicators of TC joint orientations, (b) abduction-adduction orientations of the combined joint had the greatest overall influence on TC orientations (thus, monitoring eversion-inversion and abduction-adduction orientations of the combined joint would be more valuable in predicting pronation-supination positions than monitoring only eversion-inversion orientations), and (c) foot categories based on TC and TC/talocrural joint morphology should be developed. They would provide more accurate prediction for specimen foot orientations than prediction from overall average values.

Adult↗

Vascularized periosteal bone graft from the supracondylar region of the femur.

Free, vascularized thin corticoperiosteal grafts and small periosteal bone grafts harvested from the supracondylar region of the femur are described. These grafts are nourished from the articular branch of the descending genicular artery and vein. Thin corticoperiosteal grafts consist of periosteum with a thin layer of outer cortical bone and include the cambium layer, which has a better osteogenic capacity. This graft is elastic and readily conforms to the recipient bed configuration. Thin corticoperiosteal grafts were used to treat 11 patients with fracture non-union of an upper extremity that had no massive bone defects. Early, rapid union occurred in all patients except three: one in which the anastomosed vessel became obstructed and two in which the internal fixation of the fracture was unsecured. The small bone grafts consist of periosteum, full thickness cortex, and the underlying cancellous bone. This graft can be successfully harvested without disturbing the vascularity, unlike the currently used vascularized bone grafts. This graft was used to treat three patients with avascular necrosis of the body of the talus and could prevent the necrotic talus body from progressive collapse in patients in early stages of the disease. One patient with an infectious bone defect of the first metatarsal bone was successfully treated by vascularized bone graft with an accompanying skin flap.

Adolescent↗