Purpose of the study: The tibial slope is an important parameter for knee surgery. Tibial slope designates the inclination of the tibial plateaus in the sagittal plane. The presence of a tibial slope and its value is intimately related to the condylotrochleal profile. The importance of tibial slope in knee disease and knee surgery is now universally recognised.

Material and method: We reviewed 140 cases of anterior cruciate ligament (ACL) ligamentoplasty performed at the institute; 25 failures were identified. After analysis of the position of the tunnels, particularly the femoral tunnels, the most documented cause of failure, as well as other factors of failure, we measured the mean tibial slope in all operated patients.

Results: Subjective Lachmann and the IKDC and ARPEGE scores associated with the dynamic study (TELOS) helped understand why knees can become unstable despite good surgical technique.

Discussion: William and Lissner established a mathematical relations between tibial slope and stress forces applied to the ACL. Dejour and Bonnin demonstrated the effect of the tibial slope on anterior subluxation and single leg stance. The tibial slope should thus be considered for all knee procedures. Bonnin demonstrated that an excessive slope can be a factor of plasty failure.

Adamantinoma is a primary low-grade, malignant bone tumor that is predominantly located in the mid-portion of the tibia. The aetiology of the tumor is still a matter of debate. Histologically, classic adamantinoma is a biphasic tumor characterized by epithelial and osteofibrous components that may be intermingled with each other in various proportions and differentiating patterns.

We report here a particular morphologic variant of adamantinoma characterised by the loss of classic epithelial differentiation. A 17 year-old teenager presented with a long history of a tumor in the left leg. Explorations revealed an osteolytic lesion of the middle shaft of the left tibia with a huge mass invading soft tissues. An intra medullar bone lesion with benign appearance was observed in the right tibia. CT of the chest revealed lung metastases. Histologically, we observed in the left side a pattern of spinde-celled high grade sarcoma without any evident differentiation. Spindle-shaped tumor cells express cytokeratins and vimentin. Ultrasturctural study showed tonofibrils and desmosomes and was helpful to recognize the epithelial nature of the tumour. The diagnosis of dedifferentiated adamantinoma was retained. In the right tibia biopsy revealed fibrous dysplasia. Amputation above the knee was performed followed by chemotherapy. One year later, the patient is still alive with multiple lung metastases.

In our study, we discussed the clinico-pathologic features of this particular pattern of adamantinoma as well as its association with fiobrous dysplasia in this case. A review of literature was done.

Clear cell meningioma is a rare subtype of meningiomas graded II according to the World Health Organisation classification. In spite of its benign appearance, clear cell meningioma has an aggressive behaviour and it is characterized by its inordinately tendency to metastasize.

The purpose of this study is to discuss the clinico-pathological features of this subtype of meningiomas as well as the metastatic pathways.

We wish to report a rare case of a clear cell meningioma metastasizing to the sacrum 17 years after the removal of the primary tumour. A 26 year-old man was referred to our centre for low back pain related to a lytic lesion of the sacrum. He had a history of a tumour of the forth cervical vertebra that was removed when he was 9 year-old. CT scan revealed an osteolysis of the entire sacrum invading the intrapelvic organs and the sacro-iliac joints. Open biopsy revealed a clear cell meningioma. That was the same pattern of the tumour removed 17 years earlier. Chest CT showed lung metastases. The patient was managed conservatively by palliative radiation therapy. One year later, he experienced improvement of pain and walk. The mass was stable.

Clear ell meningioma is an aggressive tumour with a potential to spread via cerebro-spinal fluid and haematologically. Patients with such a tumour should be closely followed for a long time.

Purpose: Leg fractures are a daily problem in orthopaedic surgery. The frequency has increased due to the growing number of traffic accidents. Social impact is important because the injured population is young and active. The purpose of this work was to analyse anatomic and functional results obtained in a series of patients and to identify indications and limitations of centro-medullary alignment nailing for the treatment of leg fractures.

Material and methods: This series included 207 leg fractures treated with this method at the Kassab Orthopaedic Institute. There were 174 men and 33 women, mean age 35 years (15–75). Male predominance was considerable (84%). Centromedullary nailing was completed with a plaster cast and weight bearing after a mean four to five weeks with a Sarmiento walking case until bone healing.

Results: Results were analysed at mean 12 months follow-up (4 months–18 years). Bone healing was achieved in 99% of the cases within a mean time of 15.3 weeks (6–66 weeks). There were 16 cases with a deformed callus (7.8%) predominantly in varus (n=10) and thirteen secondary dislocations (6.3%). This was significantly more frequent for fractures of the proximal third in comparison with the mid third, or comminutive bifocal fractures, and when weight bearing occurred before the fourth week.

Discussion: The functional outcome showed pain at walking in 15% of the patients. Walking distance was unlimited in three-quarters of the patients and joint motion was good. Alignment nailing is a reliable easy to use technique providing satisfactory results for the treatment of simple fractures of the mid third of the leg. Fractures of the upper and lower third, as well as bifocal and comminutive fractures require a locked nail to neutralise the risk of secondary displacement and misalignment callus.