Advertisement for orthosearch.org.uk
Results 1 - 4 of 4
Results per page:
Applied filters
Content I can access

Include Proceedings
Dates
Year From

Year To
Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_5 | Pages 21 - 21
1 Mar 2014
Currall V Kugan R Johal P Clark C
Full Access

For hallux valgus correction, distal first metatarsal osteotomy is generally used for minor to moderate deformities, diaphyseal osteotomy for moderate deformities and basal osteotomy or fusion for severe deformities. With the advent of locking plates, there has been renewed interest in opening wedge basal osteotomy. As little has been written about its geometry, we undertook this study in order to understand its power and limitations.

Proximal opening wedge osteotomies were performed on saw bone models in four orientations, with three different wedge sizes: 1. Perpendicular to the ground (PG); 2. Perpendicular to the shaft (PS); 3. Perpendicular to shaft with 30° declination (DEC); 4. 30° oblique (OB). Pre- and post-osteotomy measurements were made of axial and plantar translation and intermetatarsal angle.

Plantar translation and intermetatarsal angle correction increased with increasing wedge size. The DEC osteotomy produced the greatest increase in length of metatarsal shaft, while the PS osteotomy gave the least. The most plantar translation was achieved with the DEC osteotomy. Overall, the PS osteotomy gave the largest correction of the intermetatarsal angle.

Although there are several published clinical case series of the proximal opening wedge osteotomy, this is the first study to fully evaluate its geometry.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_I | Pages 27 - 27
1 Mar 2008
Baghla D Angel J Siddique M McPherson A Johal P Gedroyc W Blunn G
Full Access

Interventional MRI provides a novel non-invasive method of in-vivo weight-bearing analysis of the talo-calcaneal joint. Six healthy males (mean 28.8 years) underwent static right foot weight bearing MRI imaging at 0o, 15o inversion, and eversion. Using known radiological markers the motion of the talus and calcaneum were analysed.

The calcaneum externally rotates, plantar-flexes and angulates into varus. The talus shows greater plantarflexion with similar varus angulation, with variable axial rotation. Relative talo-calcaneal motion thus involves, 6o relative talar internal rotation, 3.2o flexion and no motion in the frontal plane. Concurrently the talus moves laterally on the calcaneum, by 6.5mm, with variable translations in other planes.

The calcaneum plantar-flexes, undergoes valgus angulation, and shows variable rotation in the axial plane. The talus plantar-flexes less, externally rotates, and shifts into varus. Relative motion in the axial and saggital plane reverses rotations seen during inversion. The 8o of relative valgus talo-calcaneal angulation is achieved through considerable varus angulation of the talus, in a direction opposite to the input motion. This phenomenon has not been previously reported. From coronal MRI data, comparative talo-calcaneal motion in inversion is prevented by high bony congruity, whereas during eversion, the taut posterior tibio-talar ligament appears to prevent talar valgus angulation.

We have demonstrated that Interventional MRI scanning is a valuable tool in analysing the weight-bearing motion of the talo-calcaneal joint, whilst approaching the diagnostic accuracy of stereophotogammetry. We have also demonstrated consistent unexpected talar motion in the frontal plane. Talo-calcaneal motion is highly complex involving simultaneous rotation and translation, and hence calculations of instantaneous axes of rotation cannot effectively describe talo-calca-neal motion. We would suggest that relating individual and relative motion of the talus / calcaneum better describes subtalar kinematics.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 231 - 231
1 Sep 2005
Baghla D Angel J Siddique M McPherson A Johal P Gedroyc W Blunn G
Full Access

Background: Interventional MRI provides a novel non-invasive method of in-vivo weight-bearing analysis of the subtalar joint. Preceding in-vivo experimentation with stereophotogammetry of volunteers embedded with tantalum beads has produced valuable data on relative talo-calcaneal motion (Lundberg et al. 1989). However the independent motion of each bone remains unanswered.

Materials and Methods: Six healthy males (mean 28.8 years), with no previous foot pathology, underwent static right foot weight bearing MRI imaging at 0°, 15° inversion, and 15° eversion. Using identifiable radiological markers the absolute and relative rotational and translational motion of the talus and calcaneum were analysed.

Results and Discussion: Inversion: The calcaneum externally rotates, plantar-flexes and angulates into varus. The talus shows greater plantar-flexion with similar varus angulation, with variable axial rotation. Relative talo-calcaneal motion thus involves, 6° relative talar internal rotation, 3.2° flexion and no motion in the frontal plane. Concurrently the talus moves laterally on the calcaneum, by 6.5mm, with variable translations in other planes. This results in posterior facet gapping and riding up of the talus at its posterolateral prominence. Eversion: The calcaneum plantar-flexes, undergoes valgus angulation, and shows variable rotation in the axial plane. The talus plantar-flexes less, externally rotates, and shifts into varus. Relative motion in the axial plane reverses rotations seen during inversion (2.5° talar external rotation). The 8° of relative valgus talo-calcaneal angulation is achieved consistently through considerable varus angulation of the talus, in a direction opposite to the input motion. This phenomenon has not been previously reported. From coronal MRI data, comparative talo-calcaneal motion in inversion is prevented by high bony congruity, whereas during eversion, the taut posterior tibio-talar ligament prevents talar valgus angulation.

Conclusion: We have demonstrated that Interventional MRI scanning is a valuable tool to analysing the weight bearing motion of the talo-calcaneal joint, whilst approaching the diagnostic accuracy of stereophoto-gammetry. We have also demonstrated consistent unexpected talar motion in the frontal plane. Talo-calcaneal motion is highly complex involving simultaneous rotation and translation, and hence calculations of instantaneous axes of rotation cannot effectively describe talo-calcaneal motion. We would suggest that relating individual and relative motion of the talus / calcaneum better describes subtalar kinematics.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 97 - 97
1 Feb 2003
Johal P Hunt D Tennant S Gedroyc W
Full Access

The vertical configuration open MRI Scanner (Signa SPIO, General Electric) has been used to assess the place of interventional MR in the management of developmental dysplasia of the hip over the last four years. Twenty-six patients have been studied. In static mode, coronal and axial T1 – weighted spin echo images are initially obtained to assess the anatomy of the hip, followed by dynamic imaging in near-real time.

In all cases, dynamic imaging was very good for assessing and demonstrating stability. The best position for containment can be assessed and a hip spica applied. Scanning in two planes gives more information and allows more accurate positioning than an arthrogram. Confirmation of location of the hip after application of the spica can be easily demonstrated. Adductor tenotomies have been performed within the imaging volume, and in two cases, this enabled planning of femoral osteotomies. All patients have had a satisfactory outcome, but five have required open reduction and a Salter innominate osteotomy.

In ten cases, the opportunity has also arisen to alternative perform an arthrogram, either because of the complexity of the cases, or at a later date as an alternative to a repeat MRI, or because of difficulty with access to the machine.

The place of interventional MRI in DDH is not yet defined. As machines get better and the definition improves, the amount of information about the nature of dislocation, the relative size of the acetabulum to the femoral head, the state of the limbus, the best position for containment and stability, and the potential for growth of the acetabulum, particularly posteriorly will be increased.

It follows that the potential for more accurate definition of each hip and the outcome is better – and safer – than by arthrography, which remains the ‘gold standard’ but involves radiation and is only one-dimensional.