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.

Purpose: This study examines the structural performance of different devices for the fixation of supracondylar femoral ‘T’-type intra-articular fractures.

Methods: A finite element model was developed to examine three commonly used devices for fixation of ‘T’-type unstable fractures of the distal femur:-

a retrograde distal femoral nail with condylar bolts and multi-planar locking screws,

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.

Results: Both intra-medullary nail constructs were stiffer than the DCS, with the nail with condylar bolts and multi-planar screws being stiffer than the nail with only two parallel distal locking screws. The nail with condylar bolts did, however, produce significant levels of stress within the bone before any axial load was applied – particularly in the region adjacent to the end washers. Under torsion, the nail constructs were always more effective than the side plate construct.

Conclusions: This FE model demonstrates that fixation of supracondylar femoral ‘T’-type fractures is mechanically superior with retrograde nails rather than DCS constructs. Fixation with a retrograde nail with condylar bolts plus multiplanar screws gives the stiffest fixation. High stresses are seen around the condylar bolts, but if the bone quality is adequate then the additional stiffness achieved is significant. These results support the clinical use of intra-medullary nails with compression bolts and multi-planar screws for the fixation of this type of fracture.

Specific radiological features identified by Brandser and Marsh were selected for the analysis of acetabular fractures according to the classification of Letournel and Judet. The method employs a binary approach that requires the observer to allocate each radiological feature to one of two groups. The inter- and intra-observer variances were assessed. The presence of articular displacement, marginal impaction, incongruity, intra-articular fragments and osteochondral injuries to the femoral head were analysed by a similar method. These factors were termed ‘modifiers’ and are generally considered when planning operative intervention and, critically, they may influence prognosis.

Six observers independently assessed 30 sets of plain radiographs and CT scans on two separate occasions, 12 weeks apart. They were asked to determine the presence or absence of specific radiological features. This simple binary approach to classification yields an inter- and intra-observer agreement which ranges from moderate to near-perfect (κ = 0.49 to 0.88 and κ = 0.57 to 0.88, respectively). A similar approach to the modifiers yields only slight to fair inter-observer agreement (κ = 0.20 to 0.34) and slight to moderate intra-observer agreement (κ = 0 to 0.55).

Background: The use of sacro-iliac screws to restore the stability of posterior pelvic ring dissociations has become a standard technique. Several methods are described including fluoroscopy, CT and computer assisted techniques. Fluoroscopically assisted insertion is the standard technique. Multiple exposures of ionising radiation permit acquisition of a target in sequential planes, requiring a process of interpolation for 3-D localisation. A computer assisted technique facilitates the simultaneous visualisation of multiple planes following a single image intensifier acquisition and registration process in each plane. The purpose of this study is to demonstrate the accuracy of a computer assisted surgery technique and quantify the predicted reduction in radiation exposure.

Methods: 10 embalmed human cadavers were used. In each specimen, a sacro-iliac screw was simulated by passing a 5mm reamer over a 3.2mm guide wire. The index track was formed with a closely sheathed 4.8mm drill and was inserted with the standard fluoroscopically assisted technique in the left hemipelvis and a computer assisted technique(Vector Vision trauma) on the right. Registration of the system is achieved by the placement of infra red reflective arrays on all tracked objects. These include the right and left hemi-pelvis, the fluoroscope, the drill guide and the driver unit. The system is an open platform which registers arrays of known geometry whilst permitting the registration of instruments by means of an instrument calibration matrix. The pelvic T and Y pattern fiducials are fixed rigidly to inter-table threaded pins at the level of the gluteal tuberosities. The standard acquisition projections are inlet and outlet views for both techniques with the addition of lateral projections although the latter were not directly used for navigation. Postoperative CT scans demonstrate the actual tracks and analysis is facilitated by means of a digital mapping technique.

Results: The accuracy of the fluoroscopically assisted and computer assisted techniques is identical. The procedure time was significantly longer for the computer assisted technique although most of the additional time was accounted for by the “line of sight” registration process. There was a reduction in both the total screening time and the measured radiation dose in the case of the computer assisted technique although this did not reach statistical significance as the sample size is relatively small.

Conclusions: The navigation of sacro-iliac screw tracks by means of both fluoroscopically assisted and computer assisted techniques proves equally accurate in a human cadaveric model.

Introduction Morbidity associated with wound complications may translate into disability and quality-of-life disadvantages for patients treated with radiotherapy (RT) for soft tissue sarcoma (STS) of the extremities. Functional outcome and health status of extremity STS patients randomized in a phase III trial comparing pre-operative versus post-operative RT is described.

Methods One hundred and ninety patients with extremity STS were randomized after stratification by tumor size dichotomized at 10 cm. Function and quality of life were measured by the Musculoskeletal Tumor Society Rating Scale (MSTS), the Toronto Extremity Salvage Score (TESS), and the Short Form-36 (SF-36) at randomization, six weeks, and three, six, 12, and 24 months after surgery. One hundred and eighty-five patients had function data.

Results Patients treated with post-operative RT had better function with higher MSTS (25.8 v 21.3, P < .01), TESS (69.8 v 60.6, P =.01), and SF-36 bodily pain (67.7 v 58.5, P =.03) scores at six weeks after surgery. There were no differences at later time points. Scores on the physical function, role-physical, and general health sub-scales of the SF-36 were significantly lower than Canadian normative data at all time points. After treatment arm was controlled for, MSTS change scores were predicted by a lower-extremity tumor, a large resection specimen, and motor nerve sacrifice; TESS change scores were predicted by lower-extremity tumor and prior incomplete excision. When wound complication was included in the model, patients with complications had lower MSTS and TESS scores in the first two years after treatment.

Conclusions The timing of RT has minimal impact on the function of STS patients in the first year after surgery. Tumor characteristics and wound complications have a detrimental effect on patient function.

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.