Computer-assisted total knee arthroplasty: Comparative results in a preliminary series of 72 cases

The aim of this study was to assess the value of navigation in achieving correct positioning of the implants and soft-tissue balance in total knee arthroplasty. We compared the axis alignment achieved in 72 LCS TKA's performed with navigation assistance to a historical cohort of 62 LCS TKA's implanted with the conventional instrumentation. The position of the tibial and femoral implants and the post-operative mechanical axes of the lower limbs were compared in the two series: there was a highly significant improvement in the alignment accuracy in the navigated series (p < 0.0001). There were no outliers in the computer-assisted series whereas 47% of the cases in the conventional series showed deviations of the mechanical axis of the lower limb of more than 2° from neutral alignment. However, the position of the femoral implants in rotation was not improved, suggesting that there may be a need for a more refined technique for rotational alignment of the femur, which was based essentially in the present series on ligament balance in flexion. The height of the joint line was preserved in 89% of the cases, validating the empirical use of the spreader tool prototype used during the study. Navigation eases optimal ligament balancing, by providing information that is used for appropriate release of soft tissue to achieve the proper mechanical axis. No major complication related to the use of navigation was observed. Operation time was lengthened on average by 30 minutes. Long-term studies are necessary to show whether better accuracy in ligament balancing and higher precision in restoration of mechanical axes will improve the functional results and the survival rate of knee arthroplasty. © 2005, Acta Orthopædica Belgica.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

L'ostéoblastome du cuboïde: Une localisation exceptionnelle

Osteoblastoma is a rare, bone-forming neoplasm accounting for 1% of primary bone tumours. It arises in young patients and develops in long bones and posterior elements of the spine. It is very unusual for it to be found in the foot. We report a case in a patient aged 43, revealed by inflammatory pain at the lateral edge of the foot, whose X-ray was normal both initially and after 3 months. ACT scan showed osteolytic lesion on the cuboid with no breakage of the cortical and hypersignal lesion in the MRI. Cuboid bone cyst was suspected. Curetage with allograft was performed: histological examination of the surgical specimen confirmed the diagnosis of osteoblastoma. This case was unusual in that it occurred in a patient over the age of 30 and it was located in the foot. Osteoblastoma is categorized as a benign bone tumour, although an aggressive type of osteoblastoma has been described. Recurrence following curetage can be minimized by adequate resection. © Springer Verlag 2009.SCOPUS: ar.jinfo:eu-repo/semantics/publishe