Protection of the Medial Femoral Condyle Articular Cartilage During Drilling of the Femoral Tunnel Through the Accessory Medial Portal in Anatomic Anterior Cruciate Ligament Reconstruction

Accurate positioning of the femoral tunnel in the native femoral anterior cruciate ligament (ACL) footprint requires drilling through an accessory medial portal (AMP). The AMP is located far medial and at a low level. Despite the benefits of drilling through the AMP, it is possible that the drill bit head will injure the articular cartilage of the medial femoral condyle as it slides along the guide pin to the femoral insertion of the ACL. Because more surgeons are now performing anatomic ACL reconstructions and shifting from transtibial drilling toward transportal drilling, the risk of this injury might be increasing, especially during the beginning of their learning curve. To avoid such injury, a bio-interference screw sheath is used. It is inserted through the AMP over the guide pin until it reaches near the medial wall of the lateral femoral condyle. The drill bit is inserted over the guide pin and through the bio-interference screw sheath. Using the bio-interference screw sheath not only protects the articular cartilage of the medial femoral condyle but also protects the medial meniscus, posterior cruciate ligament, and skin of the AMP from injury because of the close proximity of the drill bit head to these structures during transportal drilling

Antegrade-Retrograde Opposing Lag Screws for Internal Fixation of Simple Displaced Talar Neck Fractures

The talar neck is deviated medially with reference to the long axis of the body of the talus. In addition, it deviates plantarward. The talar neck fracture line is sometimes observed to be oriented obliquely (not perpendicular to the long axis of the talar neck). This occurs when the medially deviated talar neck strikes the horizontally oriented anterior lower tibial edge. Internal fixation of a simple displaced talar neck fracture usually requires 2 lag screws. Because the fracture line is obliquely oriented, a better method for positioning the screws perpendicular to the fracture line is to place them in a reversed direction to provide maximum interfragmentary compression at the fracture site, which could increase the likelihood of absolute stability with subsequent improvement in the incidence of fracture union and a reduction of complications, such as avascular necrosis of the body of the talus. Two lag screws are used, with the first inserted from posteriorly to anteriorly (perpendicular to the fracture line) using a medial approach after medial malleolar chevron osteotomy. The second screw is inserted from anteriorly to posteriorly (perpendicular to the fracture line) using an anterolateral approach. Both screw heads should be countersunk. A series of 8 patients underwent this form of internal fixation for talar neck fracture repair, with satisfactory functional outcomes. In conclusion, the use of antegrade-retrograde opposing lag screws is a reasonable method of internal fixation for simple displaced talar neck fractures

Verification of in vivo accuracy of Trumatch™ patient-specific instrumentation in total knee replacement using pin-less computer navigation

Purpose Accurate component alignment in total knee replacement (TKR) is one of the important factors in determining long-term survivorship. This has been achieved by conventional jigs, computer-assisted technology (CAS) and more recently patient-specific instrumentation (PSI). The purpose of the current study was to investigate the in vivo accuracy of Trumatch™ PSI using validated pin-less computer navigation system. Method Twenty consecutive selected patients that fulfilled our inclusion/exclusion criteria underwent TKR using PSI. Coronal alignment, posterior slope, resection thickness and femoral sagittal alignment were recorded using pin-less navigation. The position of the actual cutting block was appropriately adjusted prior to proceeding to definitive resections. Results The coronal alignment using PSI without the assistance of navigation would have resulted in 14 (70 %) within ±3°, 11 (55 %) within ±2° and 6 (30 %) outside acceptable alignment. Thirty-five percentage of proposed femur sagittal alignment and 55 % of posterior tibial slope were achieved within ±3°. Components size was accurately predicted in 95 % of femurs and 90 % of tibia. Conclusion The purported advantages in restoring alignments using Trumatch™ PSI alone over standard equipment are debatable. However, it predicts sizing well, and femoral coronal alignment is reasonable. Combining Trumatch™ PSI with CAS will allow in vivo verification and necessary corrections