Introduction

Because it typically afflicts older patients with poorer health and/or risk factors, spondylodiscitis can become life threatening. Lingering symptoms, which can be attributed to residual destruction as well as concurrent degenerative changes in the adjacent segments after inflammation has subsided, are frequently present after both conservative and operative therapies. Here, quality of life outcomes are presented for patients two years after operative and conservative treatment.

Despite proven advantages, pulsatile lavage seems to be used infrequently during preparation in cemented total knee arthroplasty. This remains irritating, as the technique has been suggested to improve radiological survival in cemented TKA, where aseptic loosening of the tibial component represents the main reason for revision. Furthermore, there may be a potential improvement of fixation strength for the tibial tray achieved by increased cement penetration. In this study, the influence of pulsed lavage on mechanical stability of the tibial component and bone cement penetration was analyzed in a cadaveric setting. Six pairs of cadaveric, proximal tibia specimen underwent computed tomography (CT) for assessment of bone mineral density (BMD) and exclusion of osseous lesions. Following surgical preparation, in one side of a pair, the tibial surface was irrigated using 1800ml normal saline and pulsatile lavage, while in the other side syringe lavage using the identical amount of fluid was applied. After careful drying, bone cement was hand-pressurized on the bone surface, tibial components were inserted and impacted in an identical way. After curing of cement, specimen underwent a postimplantation CT analysis). Cement distrubution was then assessed using a three-dimenionsional visualization software. Trabecular bone, cement and implant were segmented based on an automatic thresholding algorithm, which had been validated in a previous study. This allowed to determine median cement penetration for the entire cemented area. Furthermore, fixation strength of the tibial trays was determined by a vertical pull-out test using a servohydraulic material testing machine. Testing was performed under displacement control at a rate of 0,5mm/sec until implant failure. Data was described by median and range. Results were compared by a Wilcoxon matched pairs signed rank test with a type 1 error probability of 5 %. Median pull-out forces in the pulsed lavage group were 1275N (range 864–1391) and 568N (range 243–683) in the syringe lavage group (p=0.031). Cement penetration was likewise increased (p=0.031) in the pulsed lavage group (1.32mm; range 0.86–1.94), when compared to the syringe irrigated group (0.79mm; range 0.51–1.66). Failure occurred in the pulsatile lavage group at the implant-cement interface and in the syringe lavage group at the bone-cement interface, which indicates the weakness of the latter. Altogether, improved mechanical stability of the tibial implant and likewise increased bone cement interdigitation could be demonstrated in the current study, when pulsed lavage is implemented. Enhanced fixation strength was suggested being a key to improved survival of the implant. If this is the case, pulsatile lavage should be considered being a mandatory preparation step when cementing tibial components in TKA.

Introduction: Misalignment of total knee replacement components is one of the reasons for early loosening and revision surgery. Several studies have shown that using CAS (computer assisted surgery) there is a more precise positioning of the implants. So far only studies have reported about the costs of CAS. The aim of this retrospective study was to evaluate the cost of CAS for an orthopaedic unit.

Method: For analysing the costs per operation we had to include the hip resurfacing procedures as for this operative procedure CAS is used. We therefore included in our retrospective analysis 200 TKR (100 CAS, 100 conventional) as well as 60 hip resurfacing operations (30 CAS, 30 conventional). We recorded the operation time, costs for single use material, costs for man power and the leasing costs for the CAS unit.

Results: The operation time in the CAS group was prolonged (average 15 minutes). This produced extra costs of 75€. Single use equipment costs were calculated with 89€/operation. The leasing costs were 290€/operation. There was less blood loss in the CAS group with a reduced need for transfusion saving 12€/operation. Including costs for operation staff and the leasing costs we had overall costs of 442€/operation in comparison to the conventional operated group. The rate of complications was not increased using CAS.

Conclusion: Using CAS our orthopaedic unit had to spend 442€/operation for using this technique. We obtained a better alignment of the implants in both CAS groups (knee and hip) and had less blood loss. Still there is no proof that better alignment will reduce the rate of revisions and will increase the lifetime of implants.

Introduction: Quoted complication rates in older patients range from 2.5–80% after surgical treatment of LSS. There is general disagreement whether operative therapy is riskier for older versus younger spines. Using comprehensive literature review and data from the international “Spine Tango” register (www.eurospine.org), this study examines the risk of surgery for LSS relative to age.

Methods: Between May 2005 and August 2009 20’794 patients with various spinal pathologies were documented. The current study applied the following inclusion criteria:

- lumbar or lumbosacral degenerative spinal stenosis

This produced 1,493 patients, who were subdivided into three age groups:

< 65 yrs (n=609, 41%),

Results: Over 80% of patient outcomes were scaled as good or excellent by the treating physician with no significant differences between the age groups.

The surgical complication rate in the complete sample was 5.7%. Multivariate logistic regression showed surgery time (p< 0.001), fusion/rigid stabilization (p=0.025) and age group (p=0.043) as a significant co-variates for surgical complications. Group 3 had a 2.1-times higher likelihood for a surgical complication as in group 1.

The general complication rate of the complete sample was 2.9%. We found ASA (p=0.002), fusion / rigid stabilization (p=0.022) and age group (p=0.008) as significant influencing factors for general complications.

The follow-up complication rate was 10.2% and did not vary significantly between age groups, but multivariate logistic regression showed fusion/rigid stabilization (p< 0.001) and previous surgery (p=0.005) to be significant co-variates for FU complications.

Clearly age-related was the duration of hospital admission and level of ASA (both p< 0.001).

Discussion: The outcomes found in the “Spine Tango” register indicate that both surgical and general (particularly cardiovascular and urinary tract infections) complication rates after decompression for LSS are negatively influenced by age. The complication rates at FU showed no age-related variation, and according literature re-operation rates after surgery of the lumbar spine appear to actually decrease with aging.

Our study and literature leaves no doubt about that aged and very aged patients benefit from surgical treatment. Therefore, although we should be aware of the increased risk for surgical and general complications in this population, high age (> 75 yrs) should not be a main influencing factor in the choice of operative indication and strategy when treating LSS.

In the treatment of acute elbow dislocation promising clinical results have been reported on articulated external fixation and surgical reconstruction of major joint stabilizers. However, it remains unclear whether or not surgical reconstruction of the major joint stabilizers sufficiently stabilizes the elbow joint or if augmentation by a hinged elbow fixator is beneficial to provide early stability and motion capacity. The aim of the present study was to compare the stabilizing potential of surgical reconstruction versus augmentation by a hinged external elbow in a model of sequentially induced intability of the elbow.

Materials and Methods: 8 unpreserved human upper extremities were mounted to a testing apparatus which was integrated within a material testing machine. In a first series, varus and valgus moments were induced to the intact elbow joint at full extension, as well as at 30°, 60°, 90° and 120° of flexion and the mean angular displacement at 2.5, 5, an 7.5 Nm was calculated. Instability was then induced by sequentially dissecting the lateral and the medial collateral ligament, the radial head, and the posterior capsule. The elbow joint was then sequentially restabilized by osteosynthesis of the radial head and refixation of the lateral and medial collateral ligament using bone anchors. In each sequence, elbow stability was tested with and without augmentation by a hinged external fixator according to the first testing series described above. Biomechanical data of surgical reconstruction alone and surgical reconstruction augmented by external fixation were compared using an analysis of variance.

Results: In the intact elbow, varus-valgus displacement with 7.5 Nm ranged from 8,3 ± 2,4° (0°) to 11,4 ± 4,2° (90°). With the fixator applied, varus-valgus displacement was significantly lower and ranged from 4,2 ± 1,3° (0°) to 5,3 ± 2,2° (90°). After complete destabilization of the elbow joint, maximum varus-valgus displacement ranged from 17,4 ± 5,3° (0°) to 23,6 ± 6,4° (90°). Subsequent reconstruction of the collateral ligaments, the posterior capsule, and the radial head proved to stabilize the elbow joint compared with the unstable situation, however, mean varus-valgus displacement remained significantly higher when compared to the intact elbow joint. During each sequence of instability, the hinged external fixator provided constant stability not significantly different to the intact elbow joint while guiding the elbow through the entire range of motion.

Conclusion: The stabilizing potential of surgical reconstruction alone is inferior to augmentation of a hinged external elbow fixator. In order to proved primary stability and early motion capacity, augmentation of a hinged external elbow fixator in the treatment of acute dislocation of the elbow is recommended.

Aims: From 1990 until 2000 62 patients with S.u.F.E. were treated with the cologne treatment pattern (dynamic screw þxation on both sides with lateral growth reserve). We intended to investigate the medium-term subjective and objective results of this method in comparison to the usual form of treatment with osteosynthesis using Kirschner wires. Methods:The patients answered a questionnaire followed by a clinical and radiological examination. Results: 30 patients could be reexamined. We found 26 patients with good and very good results in the subjective evaluation. The lateral outclass caused only problems when the growth reserve was used up. The clinical investigation conþrmed the subjective results: Free range of motion in 25 children. The radiological examination showed normal formed femoral heads and CCD angels. Conclusion: We can show that this therapy pattern has very few complications in comparison with the with K-wires- þxation. In literature the motion of the wires and the possible infection of the soft tissue were often described. The dynamic- screw Ðsystem allows a very simple change of the screw, when the reserve of growth is used up.

Aims: Purpose of this retrospective study was to evaluate changes of pressure distribution during walking and joint movement after clubfootoperation. Methods: For this analysis the VICON 512 motion system including 12 cameras and 2 KISTLER force plates were used. Pressure distribution under both feet during gait was measured by a pressure sensitive plate (EMED NOVEL pressure plate). Muscle activity of the lateral and medial gastrocnemicus, anterior tibialis and longer peroneal muscles was registered by surface EMG using BIOVISION. The sampling rate of the motion analysis system was set at 120 Hz. Data acquisition of force and EMG signals were performed at 1080 Hz. The kinematic analysis of the human body was represented by a 7-segment model consisting of feet, lower legs, upper legs and pelvis. A set of 16 markers were used to identify the body segments. Results: 20 children with a mean age of 12 years underwent a quantitative 3-dimensional kinematic and kinetic gait analysis. Regarding to gait pattern a wide range from normal to equinal was found. Measurement of the pressure distribution during walking showed maximum pressure at different foot regions. There were only a few children with “normal” gait pattern. The striking gait pattern was combined with higher dorsalflexion in the ankle joint, missing extension and higher flexion in the knee joint. A lower extension in the hip joint was also found. Conclusions: A wide range of gait pattern was found during 3-dimensional analysis after clubfoot-operation by using the Imhaeuser method. Reasons could be the rehabilitation after operation and different daily activities of life. Work in progress is still the comparison with other methods.

Aims: In this study, the subsidence of different interbody fusion devices was investigated. Hereby, the influence of different designs as well as of the preparation technique was evaluated. Methods: 3 common cervical interbody fusion devices (BAK, Novus and WING) underwent axial compression testing with 4000 cycles in a bovine spine model. The vertebral bodies were prepared in 3 different ways, taking away 0, 1 and 2 mm of the end-plate. So each fusion device was tested in each preparation group in 5 vertebrae. Every 1000 cycles, the subsidance was measured. Results: Taking away 1 and 2 mm of the endplate resulted in a strong increase of the subsidance compared to the situation with intact end-plate. In addition, the design of the interbody device had an influence onto subsidance: In case of intact endplates, the cages with rectangular supporting areas resisted better to axial compression than the cylindrical implant. When the cortical bone of the endplate was taken away, all three implants showed similar subsidance curves. Conclusions: Implants with plane supports seem to provide better stability against subsidance than cylindrical implants. During preparation, the cortical structure of the endplate should be taken care of, especially in the zone, where the implant has its bearing areas