Introduction

Understanding knee joint biomechanics is crucial, but studying Anterior cruciate ligament (ACL) biomechanics in human adolescents is challenging due to limited availability cadaveric specimens. This study aims to validate the adolescent porcine stifle joint as a model for ACL studies by examining the ACL's behavior under axial and torsion loads and assessing its deformation rate, stiffness, and load-to-failure.

Postoperative knee stability is critical in determining the success after reconstruction; however, only posterior and anterior stability is assessed. Therefore, this study investigates medial and lateral rotational knee laxity changes after partial and complete PCL tear and after PCL allograft reconstruction.

The extending Lachman test assessed knee instability in six fresh-frozen human cadaveric knees. Tibia rotation was measured for the native knee, after partial PCLT (pPCLT), after full PCLT (fPCLT), and then after PCLR tensioned at 30° and 90°. In addition, tests were performed for the medial and lateral sides. The tibia was pulled with 130N using a digital force gauge. A compression load of 50N was applied to the joint on the universal testing machine (MTS Systems) to induce contact. Three-dimensional tibial rotation was measured using a motion capture system (Optotrak).

On average, the tibia rotation increased by 33%-42% after partial PCL tear, and by 62%-75% after full PCL tear when compared to the intact case. After PCL reconstruction, the medial tibia rotation decreased by 33% and 37% compared to the fPCL tear in the case that the allograft was tensioned at 30° and 90° of flexion, respectively. Similarly, lateral tibial rotation decreased by 15% and 2% for allograft tensioned at 30° and 90° of flexion respectively, compared to the full tear. Rotational decreases were statistically significant (p<0.005) at the lateral pulling after tensioning the allograft at 90°.

PCLR with the graft tensioned at 30° and 90° both reduced medial knee laxity after PCLT. These results suggest that while both tensioning angles restored medial knee stability, tensioning the Achilles graft at 30° of knee flexion was more effective in restoring lateral knee stability throughout the range of motion from full extension to 90° flexion, offering a closer biomechanical resemblance to native knee function.

To compare the ability of fulcrum bend and traction radiographs to predict correction of AIS using screw only implants and to assess the fulcrum bending correction index (FBCI) with a new measurement: the traction correction index (TCI)

Retrospective radiographic analysis of case series (Level IV)

Radiographic correction of scoliosis based on correction rate does not take into consideration the curve flexibility. It has been suggested that fulcrum bending radiographs predict curve correction in AIS [1]. This has been questioned [2] and has been suggested that traction radiographs are more predictive in a mixed group of patients with hybrid and screw only constructs.

Twenty three patients average age 15, who underwent posterior correction of scoliosis using pedicle screw only construct.

Analysis was carried out on the pre-op and immediate post-op AP radiographs and the pre-op fulcrum bend and traction radiographs. Correction rate, fulcrum flexibility, traction flexibility, FBCI and TCI was calculated.

Preoperative mean Cobb angle of 66 degrees was corrected to 25 degrees postoperatively. The mean fulcrum bending Cobb angle was 38 degrees and traction Cobb angle 28 degrees. The mean fulcrum flexibility was 45%, traction flexibility 59% and correction rate 63%. The mean FBCI was 182% and TCI was112%.

When comparing fulcrum bend and traction radiographs, we found the latter to be more predictive of curve correction in AIS using pedicle screw constructs. The TCI better takes into account the curve flexibility than the FBCI.

Purpose

To report a retrospective study of 103 cases of primary spinal infection, the largest ever such series from the UK, analysing presenting symptoms, investigations, bacteriology and the results of treatment.

Introduction: L5/S1 injuries can be associated with pelvic fracture but unfortunately they are often missed. Left untreated these patients may suffer disabling lower back pain. Our goal is to study the frequency of these injuries in pelvic fractures treated at this institution, thereupon to determine how many are missed and the outcome if this injury is treated conservatively. We will describe the radiological findings, anatomical features and possible surgical treatments.

Materials and Methods: A retrospective analysis was undertaken of pelvic fractures treated at this institution from 2000 onward. Outcome scores were taken from the patient records. All CT scans and x-rays were scru-tinised for a Lumbosacral Junction Injury(LJI). Numbers missed were tallied against numbers diagnosed and treated. Patient outcome measures were compared using the Matta Hip Scores. It was noted whether low back or hip pain contributed to their symptoms most.

Results: The incidence of lumbar sacral injuries associated with vertical shear pelvic fractures was 20%. Of these, 75% had not been identified as a specific lumbar-sacral injury. The remaining 25% which were identified and treated with fixation of the lumbar sacral junction had an excellent result. We have identified specific morphology patterns and propose a CT based grading system.

Discussion: We suggest that a heightened level of awareness is needed for these important injuries in pelvic trauma as their occurrence changes the management. The incidence appears to be higher than that reported by Isler and suggest our CT based classification be used to grade these injuries.

Introduction: Rotation is becoming an increasingly important consideration in the management of scoliosis yet it is difficult to measure reliably. The Perdriolle technique is a widely used and validated technique for estimating the rotation of the apical vertebra. The landmarks required to measure vertebral rotation using this technique are frequently obscured following instrumentation and the application of bone graft. We propose that the Perdriolle technique cannot be applied reliably in the presence of pedicle screw constructs.

Method: This was a manual radiographic measurement analysis comparing intraobserver and interobserver reliability of the Perdriolle “Torsiometre” and the Cobb angle measurement in scoliosis prior to and after pedicle screw instrumentation.

Results: Mean difference and 95% limits of agreement between pre-operative intra-observer readings was 2.5° (−15° and 20°). This suggests on average there was little systematic disagreement between the two readings (2.5° on average). There were large discrepancies between individual pairs of readings.

29.6% of post-operative films (17%–39%) were judged to have sufficient landmarks visible to enable measurement of vertebral rotation compared to 10% of pre-operative films.

Marked increase in systematic bias between consultants with post-operative radiographs to pre-operative films was observed.

Conclusion: We question the validity in measuring the rotation of the curve using the Perdriolle technique on post-operative films following pedicle screw instrumentation. The predominant factors for the obscuration of landmarks include the presence of bone graft, pedicle screws and rods.

We studied the long term outcome, using the Oswestry Disability Index (ODI), on patients who were managed at our institution between February, 1997, and August, 2004, with a diagnosis of a primary spinal infection, excluding TB or post-operative infection. Patients were identified from databases held within the Departments of Radiology, Orthopaedic Surgery, Neurosurgery and Microbiology. This identified 98 adult patients who fulfilled our inclusion criteria, of who ODIs were calculated on 66, with a mean follow-up of 5 years. There were initially 53 male and 45 female patients with a mean age of 60 years (range 21 0 86) at presentation and symptoms had been present on average for 72 days prior to admission. Back pain was the predominant symptom in 59 and neuropathy in 43. Our figures would suggest a mush higher incidence of primary spinal infection than previously quoted. 75% had significant co-morbidities and 85% of patients under 40 years of age were IV drug users. The causative organisms and their effect were noted. Admission WCC (mean 11.5 ± 8.6) and CRP (mean 128 ± 48) were obtained in the majority of patients (97/98 & 94/98). For those patients who were still available to f/u, the mean ODI was 32 ± 25.

Introduction: There has been controversy in recent publications for/against the value of intraoperative traction views under anaesthesia, both studies had patients with a mean standing cobb angle of 55o failing to show the predictive value of these views for curves greater than 60o.

Design: Compare predictive value of fulcrum bending views with intraoperative forced traction under anaesthesia (FTUGA) views in predicting curve flexibility; influencing the correction of curves greater than 60^o in scoliosis deformity.

Subjects: 35 patients with idiopathic scoliosis undergoing surgical correction; mean age was 19 yrs (9–40), the student’s t test and χ2 were used to assess the reliability of FTUGA views in predicting curve flexibility, degree of correction the fulcrum bending correction index (FBCI) used to measure curve flexibility and correction.

Results: The mean preoperative major curve standing and fulcrum bending views Cobb angle was 72^o (50–90), 59^o (20–82) respectively, and 37^o (14–54) on traction views. Posterior correction was performed in all patients. The mean postoperative major curve Cobb angle was 27 (10–54). The number of patients predicted for combined anterior release and posterior instrumentation was reduced from 22 to 3.

Predictive value for traction view according to standing Cobb angle was P=0.1 for Cobb angles (50–59), P=0.1 for Cobb angles (60–69), P= 0.01 for Cobb angle (70–79), P=0.01 for Cobb angle (80–90). P value for the difference between fulcrum bending views, traction views and post op correction P=0.001 in favour of traction views, the mean curve flexibility was 33%, 55% for fulcrum and traction respectively. Mean fulcrum bending and traction correction index were 232%, 123% respectively.

Conclusion: Forced Traction Under General Anaesthesia views were superior in predicting curve flexibility in curves that measured more than 70^o but weak predictor of final correction angle when performing posterior scoliosis correction.

Purpose: We describe a technique using orthoganol imaging on a radiolucent table that allows reliable, safe and reproducible insertion of thoracic pedicle screws.

Method: The popularity of pedicle screws for spinal fixation in deformity surgery has increased. Studies have shown lumbar pedicle screws to be safe and effective. The biomechanical superiority of pedicle screws has also been demonstrated. Nonetheless, reluctance to apply the technique to thoracic vertebra remains, most likely because of perceived technical difficulties and a reported high complication rate.

We describe a technique using orthoganol imaging on a radiolucent table, used in a series of patients in whom we have inserted a total of over 2000 screws.

Results: We have inserted over 2000 thoracic pedicle screws without neurological injury. In addition, this technique has allowed us to use pedicle screw to the exclusion of other, less mechanically favourable, methods of fixation to the spine; over the same time period we used only three sublaminar hooks.

Furthermore, the lateral to medial or ‘toeing in’ of screw placement gives greater pull out strength to each screw by increasing the ‘volume’ of bone that has to be overcome before failure by pull out occurs. In addition this trangulation technique allows insertion of :screws of greater diameter than the pedicle and decreases the chance of broaching medially.

Conclusion: Using the technique described, we achieve accurate screw placement ‘first time, every time’, giving us a biomechanically superior construct, allowing more powerful derotation of the spine and thus greater correction of deformity. We recommend its use for all thoracic pedicle screws.

Background: To assess reliability of traction views under GA in predicting curve flexibility when performing posterior correction of scoliosis deformity with pedicular screws.

Methods: Compare reliability of preoperative fulcrum bending film with intraoperative traction films in predicting and influencing the correction of scoliosis deformity using posterior pedicular screws. Twenty patients undergoing corrective surgery for scoliosis deformity the average age was 19 years old. The Lenke classification was used to classify the curves using pre-operative fulcrum bending views, the student’s t test was used to assess the reliability of x-ray views in predicting the end results.

Results: The mean preoperative major structural Cobb angle was 80 degrees and mean minor structural Cobb angle was 27, the mean major structural Cobb angle on fulcrum bending views was 49 degrees, the mean major structural Cobb angle on the traction views was 33.6, the minor structural Cobb angle was 9 degrees thus changing the lenke classification of the curve reducing the numbers of levels for fixation by at least one level either end of the curve. Posterior pedicular screws were used in all the patients. The number of patient at risk of combined anterior release and posterior instrumentation was reduced from 13 to 2. The P value for the difference between fulcrum bending views and traction views was P< 0.0001, for traction and end result P=0.18

Conclusion: The traction views under GA were superior in predicting curve flexibility when performing only posterior scoliosis correction with interpedicular screws reducing the number of levels required to incorporate and the number of procedures required to achieve adequate correction.

Background: To assess the correction of curves using the Fulcrum bending correction index FBCI with pedicular screws in posterior scoliosis surgery.

Methods: Compare preoperative upright and fulcrum bending views, intraoperative traction films with postoperative views to assess the correction of scoliosis deformity using posterior USS II interpedicular screws. Peri-operative complications are reviewed. Twenty patients undergoing corrective surgery for scoliosis deformity were reviewed the average age was 19 years old 4 males and 16 females, 17 were idiopathic adolescent scoliosis, 3 were neuromuscular scoliosis. The Lenke classification was used to classify the curves, the Fulcrum bending correction index (FBCI) as a percentage for assessing postoperative correction.

Results: The mean preoperative major structural Cobb angle was 80 degrees and mean minor structural Cobb angle was 27 degrees, the mean major structural Cobb angle on fulcrum bending views was 49 degrees, the mean major structural Cobb angle on the traction views was 37 degrees. Pedicular screws were used in all the patients for posterior correction; only two patients required combined anterior release. The average inter-operative blood loss was 2200 ml, the initial results suggest an of FBCI of 181% compared to Luk et al results 100.2% to 109.1% 4 different methods of posterior stabilisation.

Conclusion: Pedicular screws provided excellent segmental correction and stabilisation for posterior scoliosis correction.

Background: To describe – Forced traction radiographs under GA for operative planning; The use of segmental orthogonal image-intensification for screw insertion in thoracic & lumbar pedicles; An audit of X-ray exposure during these procedures; The use of multiple Chevron osteotomies as an alternative to anterior release; The correction of scoliosis with convex cantilever, Cotrel-Debousset manoeuvre, segmental translation, segmental rotation,” lumbar-levelling”.

Methods: We present our operative technique in addressing deformity. This represents an eclectic evolution, which we feel is sufficiently dissimilar to current standards to merit presentation. Pedicle screws are inserted at multiple levels with no recourse to hook or wires. Five reduction techniques are used and repeated.

Results: The complications of 1500 thoracic pedicle screws; the predictive value of forced traction films under GA; the Fulcrum Bending Correction Index and operative parameters of our series are submitted separately.

Conclusion: We commend consideration of some or all of our techniques to the society.

Primary disc space infections are thought to occur in children because of the abundant vascularity of the disc prior to skeletal maturity, and while they generally resolve with treatment, little is known about the long-term consequences on the spine.

An ovine model of discitis was used to investigate the effects of discitis on spinal development in the growing sheep. Six-week-old lambs underwent lumbar discography at multiple spinal levels using either radiographic contrast inoculated with Staphylococcus epidermidis (inoculated group) or radiographic contrast only (control group). Plain x-rays of the spines were taken at intervals up to 18 months before the animals were killed and the spines removed for histologic and morphometric analysis.

Discs from animals in the control group were radiologically and histologically normal at all time points, and as expected there was a steady increase in vertebral body and disc dimensions. Although not all inoculated animals showed histologic evidence of discitis, disc abnormalities were evident from an early stage. In particular disc height was significantly reduced from 2 weeks after inoculation and vertebral body dimensions were significantly reduced from one year.

Infection of discs at a young age, whether or not it progresses to discitis, has a significant effect on spinal development.