Purpose of the study: The aim of this study was to investigate the influence of bone cuts on the degree of postoperative flexion for total knee arthroplassty in patients with a potential for good postoperative recovery of flexion.

Material and methods: Adobe Photoshop and Imagika were used to process lateral radiographs of a normal knee and simulate implantation of total knee prostheses using phantom images of femoral components of decreasing size as well as variations in the tibial slope (HLS system, Tornier). The femoral and tibial images were moved until the maximal flexion angle or impingement between the posterior tibial border and the femoral cortical occurred. The same types of implantations were simulated with real implants on cadaveric bones using the Ci navigation system (Depuy) to check the position of the bone pieces and the bone cuts. The different implantations simulated involved four femoral pieces of decreasing size with a constant tibial slope. Then the same femoral implant was used varying the tibial slope by 5° increments from -5° to +10°. Rollback during flexion could be regulated by the software by controlling the position of contact of the condyle son the corresponding tibial plateau.

Results: With the two methods, reducing the posterior condylar rim 3 mm decreased the flexion angle by 10°, modifying the tibial slope 5° induced a 5° variation in the flexion angle at impingement. A 10mm posterior rollback improved the flexion angle 10° and inversely. Cumulatively, these modifications can lead to a loss of 30° flexion.

Discussion: When regulating the space in flexion, it is sometime necessary to modify the tibial slope or the posterior condylar rim by increasing the posterior condylar cut. Depending on the prosthetic kinetics, this may modify the flexion angle intraoperatively, especially if these changes are combined, decrease in the tibial slope often being associated with an increase in the posterior condylar cut.

Conclusion: The technique used for the bone cuts for a total knee arthroplasty can potentially have a significant effect on the maximal angle of maximum flexion achieved by the patient.

Aim: The operative management of proximal humerus fractures is still viewed as an unsolved question.

Surgical treatment aims at restoring anatomical elements to a condition stable enough, to allow early mobilization to avoid secondary displacement. The blood supply of the humeral head should not be damaged, so the risk of avascular necrosis will be minimal.

This work offers a new surgical technique that dramatically reduces the need for dissection of soft tissues while using a new locked plate.

Material and Method: This prospective study was carried out between August 2002 and March 2004. 47 fractures of the humerus proximal were operated on 47 patients aged 63 as an average. There were 9 four part fractures, 18 three part and 17 two part fractures.

The two arms of this Y shaped plate embrace the humeral head. The anterior arm overbridges the biceps longus tendon and fixes the lesser tuberosity, with a locked screw in the head. The posterior arm fixes the greater tuberosity with an another locked screw. These two screws cross each other at nearly right angle thus giving optimal fixation in the head.

Results: Fourty four patients (44 shoulders) were later re-examined with 10,3 months mean delay. Re-education was made immediate for 85% of the cases. The final evaluation was made with the functional Constant score and X ray control.

The main complications were 3 algodystrophies, 1 hematoma, 4 failures of fixation, 2 nonunions and only one necrosis.

Conclusion: This first clinical experience with this new implant is stimulating, since it provides a reliable fixation, even into the osteopenic bone.