Computer assisted total knee arthroplasty may have advantages over conventional surgery with respect to component positioning. Femoral component mal-rotation has been shown to be associated with poor outcomes, and may be related to posterior referencing jigs. We aimed to determine the variation between the transepicondylar axis (TEA) and posterior condylar axis (PCA) in a series of knees undergoing navigated total knee arthroplasty, and to determine the correlation between final intra-operative coronal alignment and post-operative radiographic functional alignment.

A review of 170 consecutive patients undergoing primary total knee arthroplasty between June 2007 and August 2010, using Precision navigation and Triathlon implants (Stryker). The difference between the TEA and PCA was measured as was the initial coronal alignment. Referencing of the TEA had been previously validated against computerised tomography in a previous study. During arthroplasty, neutral alignment was aimed for, and the final alignment after implant insertion was recorded. Pre- and 1 year post-operative flexion was measured. A standing four foot alignment radiograph was obtained 6 weeks after surgery to determine the weight-bearing mechanical axis.

The mean difference between the TEA and PCA was 3.94 degrees (−2.80 to 11.59) and median difference was 3.6 degrees. (A positive value implies the PCA is internally rotated with respect to the TEA). The median pre-operative flexion was 120 degrees (80–130) and the median post-operative flexion was 125 (85–145). The mean change in flexion was −2.5 degrees (−40 to 40; p=0.001). The mean intra-operative alignment was 0.75 degrees (−3 to 6, SD 1.9) and the mean radiographic alignment was 1.24 degrees (−6.5 to 6.5, SD 1.6).

Taking −3 to +3 to be neutral, the outlier rate intra-operatively was 6.5% and radiographically was 16.5%. The intra-operative and radiographic alignment showed correlation (coefficient 0.289). There was poor correlation between pre-operative deformity and degree of difference between intra-operative and radiographic alignment (coefficient −0.1).

Conclusion: There is a wide variation in the difference between the TEA and PCA, and there is not a good relationship with coronal alignment. Although most valgus knees had a bigger difference, such a difference was also seen in many varus knees. This should alert the surgeon when using posterior referencing jigs when determining the femoral component size and rotation. Although these patients achieved good post-operative flexion, this was determined by the pre-operative range. There was reasonable correlation between the final intra-operative mechanical alignment and the weight-bearing alignment as determined by a standing radiograph.

Introduction: Osteomyelitis remains a rare diagnosis and a difficult one to make. Acute osteomyelitis in the context of sickle cell disease remains the subject of some controversy, particularly with regard to aetiology. It is known that Salmonella species are more commonly the cause of acute bone infection in sickle cell patients than in patients with normal red blood cell morphology, but there has long been an argument as to whether Staphylococcus Aureus is in fact still the most common bacterial cause overall in this patient group, as it is in the population overall. We present a consecutive case series of 12 cases of acute osteomyelitis in paediatric patients in East London over the last twenty years.

Materials and Methods: Retrospective review of 12 consecutive cases. Medical Notes along with microbiology records and radiographic results were cross referenced with a paediatric sickle cell data base held by the haematology department.

Results: 10 of the 12cases had an organism isolated from either blood or bone culture(s). Salmonella spp in cases, S. Aureus in 2 cases and Pseudomonas in the remaining case

Discussion: The question of causative organism is complicated by the fact that most case series’ have bracketed adults and children together, and that conflicting conclusions have resulted from quite small, usually retrospective studies at different times and from different parts of the world – Nigeria, Saudi Arabia and the United States of America. It appears that endemicity is a result of many factors including age; race and socioeconomic factors all play a role.

Conclusion: These results reveal that in our paediatric sickle cell population, Salmonella infection occurs ore commonly than Staphylococcus.

Introduction: A review of the treatment of 33 open fractures in 29 children over the period 1997 to 2002.

Method: Intravenous antibiotics, debridement and wound irrigation was performed prior to skeletal stabilisation incorporating plaster cast immobilisation (4%), K wire fixation (13%), screw fixation (13%), flexible intramedullary nail fixation (13%) and external fixation (57%). Secondary wound closure was undertaken if appropriate at 48 hours. The tibia was involved in 49% of cases with approximately equal distribution of other long bone extremities. Fractures were classified according to Gustilo et al (22% grade I, 26% grade II, 17% grade III and 35% grade IIIb).

Results: The average age was 10 years in 22 boys and 7 girls. Tibial fracture union was an average of 9 weeks in gradeI and II compared with 20 weeks for grade III. The remaining fractures healed at an average of 10 weeks. Non union occurred in one patient (tibia). There was on case of growth arrest of the distal tibia. There were no cases of osteomyelitis.

Discussion: Open fractures in children most often result from high energy trauma. An increase in fracture and soft tissue severity is associated with a delayed union. Physeal injuries require close observation for potential growth arrest.