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PubMed2000

[Pseudarthrosis and non-union of disjunctive talar fractures].

PURPOSE OF THE STUDY: Neck fractures of the talus are rare. Necrosis is the complication most often observed. Mal union or non union are rarely reported: 11 cases of such complications have been treated and are presented with results of surgical treatment. MATERIAL: Seven non unions and 4 mal unions after separation fracture of the talus, presenting with pain and deformity of the hindfoot were treated. The treatment included removal of the fibrous tissue, heel reaxation, bone grafting, peritalar joints arthrodesis. RESULTS: Bone healing was observed in 5 of 7 non unions, and the correction of the hindfoot deformity in 9 of the 11 cases. DISCUSSION: Non union or mal union after separation fracture of the neck of the talus are poorly tolerated, the patients walking with the foot in internal rotation, bearing most of the weight on the lateral border of the foot. Such poor course results from: the less mechanical stiffness of the medial part of the talus, the severity and the comminution of the fracture, insufficienct reduction and fixation, too early weight bearing, and is associated with degenerative changes of peritalar joints. Functional and antomical good results can be obtained with bone healing, hindfoot reaxation and peritalar arthrodesis. We emphasize the interest of X Rays in the examination and the adequacy of a good initial treatment.

Adult↗
PubMed1997

[Treatment of complex fractures of the ankle and their sequellae using trans-plantar intramedullary nailing].

UNLABELLED: Nine patients were treated for complex tibial pilon and talus fractures or non unions from 1990 to 1997 using intramedullary nails introduced through the calcaneus. All patients were followed until healing. The average follow-up was 14 months. Failure of the procedure was defined by the occurrence of complications or reintervention. We used a modified Seidel nail in 5 cases, a tibial shaft nail in 3 cases, and a special nail in one case. All nails but two were locked. CASES: These arthrodeses were performed for treatment of sequels from open talus fractures. Transplantar nailing was performed between 9 months and 3 years after arthrodesis, because of non union. In two cases fusion was obtained at 3 and 8 months postoperatively. In the third case non union occurred due to instability of fixation (the nail was unlocked). Replacement by an interlocked nail was performed through a proximal tibial approach, and healing was obtained in 6 months. PSEUDARTHROSES: 2 CASES: These two cases presented comminuted tibial pilon and open talus fractures in association with vascular and tendon lesions. They had previously undergone debridement and external fixation. Transplantar nailing was performed 8 and 10 months after trauma using a locked modified Seidel nail. Radiographic fusion was obtained in 5 months. PRIMARY SURGERY: 4 CASES: The first two cases were foot reimplantations after traumatic amputation. Skeletal stabilization was obtained using a transplantar locked tibial nail. Revascularization attempts failed and an amputation was performed on the fourth day in one case. The reimplantation succeeded in the second case. Radiographic fusion was obtained in 2 months. The third case was a distal tibial shaft fracture. The patient was an obese mentally deficient and invalid woman. Bone union was achieved in four months. The last case was a primary arthrodesis for post-trauma necrosis of the talus. Radiographic fusion was observed 45 days after operation. Transplantar locked nailing offers an optimal stabilization for complex ankle fractures. We had two failures not related with the principle of the technique. We think that transplantar nailing is best indicated to obtain tibiotalar or tibiocalcaneal arthrodesis and to treat compound ankle fractures. Another indication could be distal tibial shaft fractures in invalid or mentally deficient patients.

Adolescent↗
PubMedDate not supplied

Biomechanical topography of human ankle cartilage.

The material properties of normal cadaveric human cartilage in the ankle mortice (tibiotalar articulation) were evaluated to determine a possible etiologic mechanism of cartilage injury of the ankle when an obvious traumatic episode is not present. Using an automated indentation apparatus and the biphasic creep indentation methodology, creep indentation experiments were performed in five sites in the distal tibia, one site in the distal fibula, and eight sites in the proximal talus of 14 human ankles (seven pairs). Results showed significant differences in the mechanical properties of specific human ankle cartilage regions. Topographically, tibial cartilage is stiffer (1.19 MPa) than talar cartilage (1.06 MPa). Cartilage in the anterior medial portion of the tibia has the largest aggregate modulus (HA = 1.34 MPa), whereas the softest tissue was found to be in the posterior lateral (0.92 MPa) and the posterior medial (0.92 MPa) regions of the talus. The posterior lateral ridge of the talus was the thickest (1.45 mm) and the distal fibula was the thinnest (0.95 mm) articular cartilage. The largest Poisson's ratio was found in the distal fibula (0.08). The lowest and highest permeability were found in the anterior lateral regions of the astragalus (0.80 x 10(-15) m4N-1sec-1) and the posterior medial region of the tibia (1.79 x 10(-15) m4N-1sec-1), respectively. The anterior and posterior regions of the lateral and medial sites of the tibia were found to be 18-37% stiffer than the anatomically corresponding sites in the talus. The biomechanical results may explain clinically observed talar dome osteochondral lesions when no obvious traumatic event is present. Cartilage lesions in a repetitive overuse process in the ankle joint may be related to a disparity of mechanical properties between the articulating surfaces of the tibial and talar regions.

Adolescent↗
PubMed2005

[The transfibular approach for ankle arthrodesis].

OBJECTIVE: Bony fusion between tibia and talus in neutral position of foot. Return to a pain-free function of the lower limb. INDICATIONS: Extensive loss of articular cartilage accompanied by a painful and considerably limited motion with or without malalignment. Partial avascular necrosis of talar dome or distal tibial epiphysis. Neuroarthropathy (Charcot joint) with progressive malalignment of ankle. Revision surgery after failed total ankle arthroplasty. CONTRAINDICATIONS: Acute purulent joint infection. Total avascular necrosis of talus. SURGICAL TECHNIQUE: Posterolateral approach to the distal fibula taking care to preserve the periosteal vessels. Fibular osteotomy from proximal lateral to distal medial. Division of the anterior tibiofibular, anterior fibulotibial, and fibulocalcaneal ligaments. Division of posterior tibiofibular ligament. Transverse planar resection of tibial and talar articular surfaces. Freshening of the medial malleolus. Resection of the tip of medial malleolus through a medial incision. Positioning of talus perpendicular to the tibia, paying attention to the valgus of the hindfoot and external rotation. Temporary fixation with Kirschner wires. Radiographic control in two planes followed by fixation with two or three lag screws. Removal of the medial fibular cortex, freshening of the lateral gutter, and fixation of the distal fibular fragments to tibia and talus with cortical screws. RESULTS: 20 arthrodeses in 19 patients were followed up for an average of 39 months (12-69 months). All arthrodeses were fused. In one patient a fibular pseudarthrosis was encountered. All arthrodeses healed in a correct position but one that consolidated with a pes equinus of 3 degrees . The average AOFAS (American Orthopedic Foot and Ankle Society) hindfoot score reached 78.5 points (40-86 points). A marked reduction of symptoms and satisfactory function were reported postoperatively by all patients. All would be willing to undergo surgery again.

Adult↗
PubMed2005

Influences of chronic and current season grazing by collared pikas on above-ground biomass and species richness in subarctic alpine meadows.

We studied an alpine herbivory gradient established by collared pikas, a small central place foraging lagomorph, to examine the effects of multiple grazing levels on above-ground live biomass (AGB) and species richness (SR) in alpine tundra. The effects of within-season (four sampling periods), multi-season (across three summers) and longer-term dynamics (inferred from spatial location of vegetation with respect to pika haypiles) were examined. Along the grazing gradient, we found support for and against hypotheses that propose biphasic, increasing, or decreasing responses to herbivory, both in terms of AGB and SR. Our results suggest that plant-herbivore predictability is still weak. To further examine the impact of herbivory, we experimentally removed pikas using mesh exclosures placed at increasing distance from the edge of talus occupied by pikas. AGB after the second consecutive year of herbivore exclusion increased by 125% compared to control plots in highly grazed areas adjacent to talus (<1 m). In more lightly grazed sites at distances 1-6 m from talus, AGB increased by more than 40% after pikas were removed. No differences were observed in the ungrazed sites >6 m from talus. AGB was highest in meadow patches previously grazed by pikas compared to those with little grazing history, but this response was only observed after two seasons following release from herbivory. Grazed sites at distances of 1-6 m had the highest SR. These results indicate that multi-year measurements of growth are particularly relevant in ecosystems dominated by long-lived perennials in regions where productivity is low. Infrequent herbivore vacancies may provide local short-term release from pika grazing, thereby contributing to the persistence of productive, highly palatable vegetation.

Animals↗
PubMed1989

Ankle fusion: a new technique of internal fixation using a compression blade plate.

A new technique of tibiotalar arthrodesis has been developed offering wide exposure, excellent correction of deformity, good bony apposition, and blade plate fixation. This technique has even been effective in cases of ischemic necrosis of the talus. A modified pediatric blade plate is used to effect compression of the talus to the tibia and to provide stability against flexion/extension and varus/valgus movement. Fixation is augmented by a lateral fibular struct screwed to the tibia and talus. In this series, 17 compression blade plate tibiotalar arthrodeses were performed. Follow-up averaged 48 months (range 13 to 85 months). Preoperative diagnoses included postraumatic degenerative arthritis, rheumatoid arthritis, and ischemic necrosis of the talus. Solid fusion was achieved in 16 of 17 patients (94%) with a painless, stable pseudarthrosis in the remaining one. Time to fusion averaged 4 months (range 2 1/2 to 6 months). Functional clinical results were excellent in 12 and good in 4 patients. Of 14 patients evaluated by the Mazur scale, 10 scored within the range of excellent; 2, good; and 2, fair.

Aged↗
PubMed2002

Kinematic behavior of the ankle following malleolar fracture repair in a high-fidelity cadaver model.

BACKGROUND: Previous studies involving axially loaded ankle cadaver specimens undergoing a passive range of motion after fracture have demonstrated rotatory instability patterns consisting of excessive external rotation during plantar flexion. The present study was designed to expand these studies by using a model in which ankle motion is controlled by physiologically accurate motor forces generated through phasic force-couples attached to the muscle-tendon units. METHODS: Eight right unembalmed cadaver feet were tested in a dynamic gait simulator that reproduces the sagittal kinematics of the tibia while applying physiological muscle forces to the tendons of the major extrinsic muscles of the foot. Six-degrees-of-freedom kinematics of the tibia and talus were measured with use of a VICON motion-analysis system. The experimental conditions included all combinations of lateral and medial injury to reproduce the clinical classifications of ankle fracture. Statistical analysis was performed with repeated-measures analyses of variance. RESULTS: The talus of the intact ankles demonstrated coupled external rotation and inversion relative to the tibia as the ankle plantar flexed. Osteotomy of the fibula, simulating a lateral ankle fracture, slightly but significantly increased external rotation and inversion of the talus (p < 0.001), whereas disruption of either the superficial or the deep deltoid ligament increased talar eversion (p < 0.003) and disruption of the deep deltoid ligament increased internal rotation (p < 0.0001). The aberrant motions were corrected by repair of the injured structure. CONCLUSIONS: The predominant coupled rotation of the talus is external rotation associated with plantar flexion. Following progressive ankle destabilization, talar external rotation and inversion increased. CLINICAL RELEVANCE: The clinical decision-making process regarding the treatment of ankle fractures centers on determination of whether the injury is expected to result in abnormal motion, which is thought to predispose to the development of arthritis. The present study demonstrated a remarkable degree of ankle stability during stance phase even when there was severe disruption of medial and lateral structures. This finding suggests that a main determinant of clinical outcome after ankle fracture may be ankle motion during swing phase, when ankle stability is not augmented by the combination of axial loading and active motor control of motion. If swing-phase motion is abnormal, then the ankle may be in a vulnerable position at the point of heel-strike.

Aged↗
PubMed1993

Relationship between the ossification center and cartilaginous anlage in the normal hindfoot in children: study with MR imaging.

OBJECTIVE: Although many reports have documented when ossification centers can first be visualized on radiographs, few studies have evaluated the position of the ossification center within its cartilaginous anlage. In the skeletally immature child, the ossification centers of the tarsals are used to evaluate the positions of the tarsals and their interrelationships. It is convenient to assume that tarsal ossification begins in the center of its cartilaginous anlage and proceeds in a radial fashion; however, this may not be the case. Accordingly, we used MR imaging to evaluate the location of the ossification centers of the tarsals within their cartilaginous anlage in the mid and hindfoot in children. MATERIALS AND METHODS: MR studies of 69 feet in 40 children, 3 months to 7 years old (mean, 2.5 years), were reviewed retrospectively. The location of the ossification center within its cartilaginous anlage and the percentage of ossification of the cartilaginous anlagen of the talus, calcaneus, cuboid bone, and navicular bone were determined from coronal and sagittal images. In the talus, the difference between the orientation of the long axis of its ossification center and the long axis of its cartilaginous anlage was measured on coronal and sagittal images. RESULTS: Early talar ossification was centered on the neck of the talus; the proximal aspect of the bone ossified last. The long axis of the talar ossification center and the long axis of its cartilaginous anlage differed in orientation. Early calcaneal ossification was centered on the distal two thirds of the cartilaginous anlage of the calcaneus; the proximal aspect and the area of the subtalar joint ossified last. Early navicular ossification was centered on the central or lateral third of the navicular cartilaginous anlage; the medial aspect ossified last. The ossification center of the cuboid bone was in the middle of the cuboidal cartilaginous anlage. CONCLUSION: Our results show that early ossification in the talus, calcaneus, and navicular bones does not begin in the center of the bones' cartilaginous anlagen. The orientations of the long axis of the talar ossification center and the long mid axis of its cartilaginous anlage are different. Therefore, part of the changes in the alignment of the tarsals seen on radiographs with growth is due to ossification beginning and proceeding eccentrically within the cartilaginous anlage and not to a true change in the alignment of the tarsals. These data provide new information about the normal development of the child's hindfoot and midfoot.

Cartilage↗
PubMed1991

Revision arthrodesis for tibiotalar pseudarthrosis with fibular onlay-inlay graft and internal screw fixation.

Pseudarthrosis after failed tibiotalar arthrodesis was successfully treated surgically in nine of 11 patients between 1980 and 1987. The indication for the initial attempted arthrodesis was traumatic arthrosis in seven patients, traumatic arthrosis with osteonecrosis of the talus in two patients, degenerative arthrosis in one patient with cavovarus foot (Charcot-Marie-Tooth), and myelodysplasia with progressive valgus deformity of the foot and ankle in one. The surgical technique planned for revision arthrodesis provided firm coaptation of tibia to talus with internal fixation that maintained the foot at right angles to the tibia with the forefoot in neutral position. Seven feet in 11 patients were treated using a transfibular approach that allowed excision of fibrous tissue and sclerotic bone, decortication of the media malleolus, fixation of the tibia to the talus with cancellous screws, and onlay/inlay fibular graft. Of the remaining four patients, one was treated with medial compression plate, a second was treated using an anteromedial cortical graft, a third was treated by a combination of sliding anteromedial corticocancellous graft and tibiotalar compression screw, and a fourth was treated with tibiotalar compression screw. Clinical and roentgenographic union occurred in nine of 11 patients. One patient developed a painless, fibrous union and one patient with persistent pseudarthrosis had myelodysplasia and severe valgus deformity and required amputation. Adequate exposure was possible through the transfibular approach to provide cancellous bone opposition, to excise the pseudarthrosis membrane and sclerotic bone, and to remove necrotic segments of the talus. In addition, supplemental bone graft, internal fixation, and postoperative cast immobilization were also helpful in obtaining union.

Adolescent↗
PubMed1978

The pathoanatomy of congenital clubfoot.

Patients with resistant clubfeet were reviewed in their second and third decades. For comparison, normal embryological and fetal feet, untreated clubfeet, a recurrent clubfoot, and an amputated foot were dissected. In no child with a resistant clubfoot was the bone architecture normal. In untreated and recurrent clubfeet we found the lateral malleolus to be directed posteriorly, the head of the talus pointed laterally, and the navicular subluxated medially toward the medial malleolus. An operative technique to restore normal alignment of the talus in the ankle mortice, of the navicular and talus, and of the talus and os calcis is described.

Adult↗
PubMed2005

The detached osteochondral fragment as a source of cells for autologous chondrocyte implantation (ACI) in the ankle joint.

OBJECTIVE: Autologous chondrocyte implantation (ACI) has been successfully used for the treatment of osteochondral lesions of the talus. One of the main problems of this surgical strategy is related to the harvesting of the cartilage slice from a healthy knee. The aim of this study was to examine the capacity of chondrocytes harvested from a detached osteochondral fragment to proliferate and to serve as a source of viable cells for ACI in the repair of ankle cartilage defects. METHODS: Detached osteochondral fragments harvested from the ankle joint of 20 patients with osteochondral lesions of the talus served as the source of human articular cartilage specimens. All of the osteochondral lesions were chronic and of traumatic origin. In all cases, the fragments were utilized to evaluate the viability and proliferation of the cells, the histological appearance of the cartilage tissue and the expression of specific cartilage markers by real-time polymerase chain reaction (PCR). In the 16 patients scheduled for ACI, the expanded chondrocytes were used for chondrocyte implantation. In the other 4 patients, with lesion size <1.5cm(2), microfractures were created during the initial arthroscopic step. As a control group, 7 patients with comparable osteochondral lesions underwent the same surgery, but received chondrocytes harvested from the ipsilateral knee. RESULTS: According to the American Orthopaedic Foot and Ankle Scoring (AOFAS) system, patients in the experimental group had a preoperative score of 54.2+/-16 points and a postoperative one of 89+/-9.6 points after a minimum follow-up time of 12 months (P<0.0005). The control group of patients had a preoperative score of 54.6+/-11.7 points and a postoperative one of 90.2+/-9.7 points at a minimum follow-up time of 12 months (P<0.0005). The clinical results of the two groups did not differ significantly from each other. Chondrocytes isolated from the detached fragments were highly viable, phenotypically stable, proliferated in culture and redifferentiated when grown within the three-dimensional scaffold used for ACI. The morphological and molecular characteristics of the cartilage samples obtained from the detached osteochondral fragments were similar to those of healthy hyaline articular cartilage. CONCLUSIONS: The good results achieved with this strategy indicate that cells derived from the lesioned area may be useful in the treatment of osteochondral defects of the talus.

Adult↗
PubMed1988

Total talar dislocation.

Five patients with the very rare injury of a total dislocation of the talus were retrospectively studied. Rapid open reduction had successfully been performed in all patients. The mean followup was 4.5 years. Two cases developed an avascular necrosis of the talus. No talectomy was performed. The clinical results were good in three and fair in two patients. It is concluded that the choice of treatment is a rapid open reduction. In case of an avascular necrosis of the talus, weight bearing must be postponed. A talectomy must be avoided.

Adult↗
PubMedDate not supplied

Operative ankle arthroscopy. Long-term followup.

Ankle arthroscopy has become an accepted procedure for the treatment of various intraarticular disorders. More than 100 ankle arthroscopies have been performed at our institution since 1983. To better define the role of arthroscopic surgery in the treatment of ankle disorders, we evaluated the preoperative examination and indications, operative data, and radiographs of those patients with a minimum of 1 year of followup. Fifty-eight ankles in 57 patients were identified; their average follow-up period was 25 months (range, 12 to 49 months). Preoperative diagnoses were synovitis (26), transchondral defects of the talus (17), degenerative joint disease (8), and osteophytes or loose bodies (7). Subjective results were good or excellent in 64% of cases. The best overall results were achieved in patients with synovitis (77%) and transchondral defects of the talus (71%). Degenerative joint disease patients did not do well. They had only 12% good or excellent results and a 43% rate of subsequent fusion. Complications included superficial and deep infections, temporary and permanent paresthesias, and hemarthroses; the overall complication rate was 15%. In conclusion, operative ankle arthroscopy can be useful in selected patients. It is an effective surgical procedure in patients with synovitis and transchondral defects of the talus. The benefits and long-term results are less predictable with loose bodies and impinging osteophytes; the results are poor with degenerative joint disease. There appears to be a significant risk of complication with ankle arthroscopy; however, with proper indications, a thorough knowledge of anatomical landmarks, and meticulous technique, good results can be obtained.

Adolescent↗
PubMedDate not supplied

Reconstruction of the lateral ankle ligaments. A biomechanical analysis.

UNLABELLED: The purpose of this study was to perform a biomechanical analysis of several commonly performed operative procedures used to stabilize the lateral ankle. We performed the Evans, Watson-Jones, and Chrisman-Snook procedures on 15 cadaveric ankles and tested the ankles for stability, motion, and isometry of graft placement. The Evans procedure allowed increased anterior displacement, internal rotation, and tilt of the talus when compared to ankles with intact ligaments. Subtalar joint motion was restricted by the Evans procedure. The Watson-Jones procedure controlled internal rotation and anterior displacement of the talus, but was less effective in controlling talar tilt and also restricted subtalar joint motion. The Chrisman-Snook procedure allowed increased internal rotation and anterior displacement of the talus when compared to ankles with intact ligaments. The procedure was effective in limiting talar tilt, but restricted subtalar joint motion. Based on the biomechanical data obtained, we devised a lateral ankle reconstruction with bone tunnels that reproduce the anatomic orientation of both the anterior talofibular and calcaneofibular ligaments. This ankle ligament reconstruction resists anterior displacement, internal rotation, and talar tilt without restricting subtalar joint motion. CLINICAL RELEVANCE: We found considerable mechanical differences among the more commonly performed lateral ankle reconstructions. It is possible to locate bone tunnels and graft placement so that a more anatomic configuration is achieved.

Adult↗
PubMed2000

Treatment strategies in osteochondral defects of the talar dome: a systematic review.

The aim of this study was to investigate the results of different treatment strategies for osteochondral defects (OCD) of the talus. Electronic databases from 1966 to July 1998 were systematically screened. Based on our inclusion criteria 32 studies describing the results of treatment strategies for OCD of the talus were included. No randomized clinical trials (RCT's) were identified. Fourteen studies described the results of excision alone, 11 the results of (EC), 14 the results of (ECD), 1 the results of cancellous bone grafting after EC, 1 the results of osteochondral transplantation and 3 the results of fixation. The average success rate of non-operative treatment (NT) was 45%. Comparison of different surgical procedures shows that the average highest success rate was reached by excision, curettage and drilling (ECD) (85%) followed by excision and curettage (EC) (78%) and excision alone (38%). Based on this systematic review we conclude that NT and excision alone are not to be recommended in treating talar OCD. Both EC and ECD have been shown to lead to a high percentage good/excellent results. However, due to great diversity in the articles and variability in treatment results, no definitive conclusions can be drawn. Further prospective randomized controlled trials are required to compare the outcome of these two surgical strategies for OCD of the talus.

Adolescent↗
PubMed2002

Autologous osteochondral grafting for talar cartilage defects.

The purpose of this study was to evaluate the clinical results of Osteochondral Autograft Transfer System (OATS) for the treatment of symptomatic osteochondral defects of the talus using standardized outcome analysis. Nineteen patients with symptomatic osteochondral defect (OCD) of the talus were treated with autologous osteochondral grafting. There were six men and 13 women. The average age was 32 years (range, 18 to 48 years). The average duration of symptoms prior to surgery was 4.2 years (range, three months to 12 years). All patients had failed nonoperative treatment, and 13 (68%) patients had failed prior excision, curettage and/or drilling of the lesion. The average size of the lesion prior to autografting was 12 mm x 10 mm (range, 10 x 5 mm to 20 x 20 mm). Donor plugs were harvested from the trochlear border of the ipsilateral femoral condyle. Ankle exposure was obtained with a medial malleolar osteotomy in 13 patients, arthrotomy in five patients and lateral malleolar osteotomy in one patient. Clinical evaluations were performed for both the recipient ankle and donor knee using the AOFAS Ankle/Hindfoot Scale and Lysholm knee scale, respectively. The average follow-up time was 16 months (range, 12 to 30 months). The average postoperative AOFAS ankle score was 88 (range, 60 to 100). Most patients had occasional mild pain, but excellent function, range of motion, stability and alignment. The average postoperative ankle score for the 13 patients who failed prior surgery was 91 (range, 84 to 100). The average postoperative Lysholm knee score was 97 (range, 87 to 100). Only two patients had mild knee pain. Postoperative radiographs were available for 13 patients. There was no evidence of graft subsidence and all grafts healed. All malleolar osteotomies united. Seventeen (89%) patients said that they would undergo the procedure again. The results of osteochondral autograft transplant for OCD lesions of the talus demonstrate excellent postoperative ankle scores including improvement of pain and function with minimal knee donor site morbidity. Also, our results indicate that this is an effective salvage procedure following failed previous procedures and for patients with longstanding symptoms.

Adolescent↗
PubMed2004

Variations in fibular position, talar length, and anterior talofibular ligament length.

BACKGROUND: Proprioceptive deficiencies, peroneal muscle weakness, varus hindfoot, and varus tibial plafond have each been implicated as a predisposing factor in recurrent ankle instability. Another predisposing factor for instability is a position of the fibula posterior to the transverse axis of the talus. This study examined the relationship of fibular position and ankle instability with anatomic dissection and magnetic resonance imaging (MRI). METHODS: Data were obtained from 100 consecutive MRI scans of adult ankles: the malleolar index in degrees and the fibular position anterior or posterior to the anteromedial malleolar plane and relative to the transverse axis of the talus. Twenty cadaver ankles also were studied by MRI and then by anatomic dissection. The malleolar index, the talar length, and the length of the anterior talofibular (ATF) ligament were recorded. RESULTS: The MRI study showed that variation of the malleolar index ranged from 2 to 30 degrees. There was no correlation between the malleolar index and the talar length or the length of the ATF ligament. CONCLUSIONS: There is a bell-shaped curve of variation of the position of the fibula relative to the transverse axis of the talus. An ankle mortise with a more posteriorly positioned fibula has less structural stability and is more susceptible to sprain. Neither talar length nor ATF ligament length correlated with fibular position.

Adult↗
PubMed2006

Distal fibular length needed for ankle stability.

BACKGROUND: The fibula is commonly used for bone grafts. Previous clinical and biomechanical studies have suggested that the length of the residual portion of the distal part of the fibula has an important effect on the long-term stability of the ankle joint. However, we cannot find clear-cut guidelines for the amount of bone that can be harvested safely. METHODS: Using six normal fresh-frozen cadaver legs, motions of the tibia, talus and calcaneus were measured. The fibula was cut sequentially 3 cm from the proximal tip of the fibula and distally 10 cm, 6 cm, and 4 cm from the distal tip of the lateral malleolus. The angular motion of each bone was measured while a medial and lateral traction force of 19.6 N was applied to the proximal tibia. Angles of the tibia, talus, and calcaneus were measured. RESULTS: Sequential resection of the fibula increased the inversion angles of the ankle joint. The proximal 3-cm cut increased the inversion angle from 42.1 +/- 6.2 degrees to 49.6 +/- 3.6 degrees, and the distal 4-cm cut increased the angle from 57.6 +/- 6.6 degrees to 67.4 +/- 5.9 degrees. The rotational angles were almost constant with sequential resections of the fibula; however, the distal 4-cm cut increased the rotational angle from 11.3 +/- 25.1 degrees to 78.7 +/- 37.5 degrees. CONCLUSIONS: The whole fibula including the head is essential for the stability of the ankle joint complex, and the distal fibula is responsible for stabilizing the ankle mortise during external rotation and inversion. We recommend fixation of the syndesmosis or bracing to prevent ankle joint instability with rotation of the talus in the mortise, especially when the distal fibula is shortened 6 cm or more.

Aged↗