No abstract

Purpose Prior studies have reported improved gait performance and kinematics after total ankle arthroplasty (TAR) compared to ankle arthrodesis (AAD). Given these findings, AAD has been primarily considered as a salvage procedure that may lead to adjacent joint degeneration. Methods A total of 101 TAR and 40 screw arthrodeses were enrolled in a retrospective study with a prospectively designed follow-up examination that included gait analysis and outcome assessment with the AOFAS hindfoot score and FAOS questionnaire. Results Significant asymmetry in gait and reduced range of motion compared to normal remained after both procedures. Subjective outcome improved after both procedures, and pain was significantly better after TAR. Limited functional gains after TAR and joint degeneration to the same degree after both procedures was seen in the mid-term. Hindfoot fusion seemed to have a greater impact on postoperative function than ankle arthrodesis. Conclusion Considering only minor functional gains of TAR compared to AAD the implantation of current TAR designs in large patient series may be questioned.

Level III, comparative series.

In revision total hip replacement, bone loss can be managed by impacting porous bone chips. In order to guarantee sufficient mechanical strength, the bone chips have to be compacted. The aim of this study was to determine in an in vitro simulation whether the use of a pneumatic hammer leads to higher primary stability than manual impaction. Bone mass characteristics were measured by force and distance variation of a penetrating punch, which was lowered into a plastic cup filled with bone chips. From these measurements bulk density, contact stiffness, impaction hardness and penetration resistance were calculated for different durations of impaction. We found that the pneumatic method reached higher values of impaction hardness, contact stiffness and bulk density suggesting an increase in stability of the implant. No significant differences were found between the two different methods concerning the penetration resistance. The pneumatic method might reduce the risk of fracture in vivo, as force peaks are smaller and applied for a shorter period. Results from manual impaction showed higher variability and depend much on the experience of the surgeon. The pneumatic hammer is a suitable tool to standardise the impaction process.