Crescent fractures are represented by a spectrum of morphological fracture patterns, sharing a common mechanism of injury. We propose three distinct types according to the extent of Sacroiliac (SI) joint involvement and the size of the crescent fragment, which enables a pragmatic choice of surgical approach and stabilisation technique. Crescent fractures are fracture dislocations of the SI joint in which there is variable amount of disruption of the SI ligaments extending proximally as a fracture of the posterior iliac wing. We identified three groups of Crescent fractures according to the extent of SI joint involvement, relationship of the fracture line to the S1 and S2 nerve root foramina on anteroposterior and outlet plain radiograph views, and CT films. Type I involves the less than inferior third of the SI joint with a large posterior iliac fragment left attached to the sacrum. This is best approached anteriorly for stabilisation. Type II has between one-third to two-thirds involvement of the SI joint and is treated according to Helfet's technique. Type III has a very small crescent fragment left attached to the sacrum and the inferior two-thirds of the SI joint is disrupted. This is treated with percutaneous SI screws, but will need anterior open reduction in delayed presentations. Based on this, we treated sixteen patients and followed them for at least two years. There were four Type I, four Type II and eight Type III fractures. Fifteen had anatomical reduction and stabilisation of the SI joint with good functional results. Delayed referral, the presence of significant soft tissue injury posteriorly and infected external fixator pins. From our experience we would like to propose this functional classification of crescent fractures which we find useful in making a choice of surgical approach and stabilisation technique to achieve satisfactory reduction and stabilisation of sacroiliac joint.
a retrograde distal femoral nail with condylar bolts and multi-planar locking screws, a retrograde nail with two parallel distal screws, and a dynamic condylar screw and plate construct. The distal femoral geometry was been taken from the BEL repository. The bone was aligned with the mechanical axis and a compressive load of 2000N and separately a torsion load of 10Nm were applied. A fracture was introduced by removing a transverse 15mm slice of material and a saggital slice of 1mm thickness. The FE model examined whether any of the constructs was markedly stiffer than any other.
The aim of this study was to identify potential inflammatory mediators in herniated and non-herniated intervertebral disc. It has been suggested that inflammation of the nerve root is a pre-requisite for disc herniations to be symptomatic. What leads to this inflammation is a matter of conjecture; one possible cause may be inflammatory mediators released from the herniated disc tissue itself. In this study we have examined discs from individuals with and without disc herniations to determine if there is a different degree of occurrence. Twenty two discs from 21 patients with disc herniation were examined together with four discs from patients with other disc disorders and five age-matched discs from individuals obtained at autopsy. Samples were studied for the presence of blood vessels and inflammatory cytokines: IL-1α and β, IL-6, INOS, MCP1, TNFα, TSG-6 and thromboxane. Of the herniated discs 10 were protrusions, six extrusions and six sequestrations. There was less of all the cytokines in the non-herniated discs than found in the herniated, with very little immunostaining for iNOS or IL-1α in any samples. Staining was seen in all herniated samples for IL-1β, but in fewer for IL-six and MCP1 (86%), thromboxane (68%), TNFα (64%) and TSG-6 (59%). The presence of cytokines was strongly associated with the presence of blood vessels. Protruded discs had less TNFα and thromboxane than sequestrated or extruded discs. Cytokines appear to play an active role in the aetiopathogenesis of disc herniations. Some may be involved in the stimulation of degradative enzymes and hence resorption of, for example, sequestrations, whereas others may be responsible for an inflammatory response in the surrounding tissues such as nerve roots.