Biomechanical comparison of the three techniques for arthroscopic suprapectoral biceps tenodesis: implant-free intraosseous tendon fixation with Cobra Guide, interference screw and suture anchor.

PURPOSE: A new arthroscopic technique with Cobra Guide (CG) was developed to enable fast, controlled and strong intraosseous biceps tenodesis while avoiding an implant. The purpose of this study was to compare the newly developed suture-only biceps tenodesis technique [arthroscopic suprapectoral intraosseous implant-free biceps tenodesis (ASIIBT) with the new CG] to classical interference screws (IS) and suture anchors (SA) in terms of construct resistance to failure. MATERIALS AND METHODS: Fifty-eight human cadaveric shoulders were randomized into three treatment groups. Twenty shoulders received an IS, 19 SA and 19 ASIIBT. A biceps tenodesis was performed according to the techniques listed above. Cyclic loading tests on a dynamic loading testing device were used to measure and compare the resistance to failure pullout between the three groups. Hartley's Fmax test and Tukey's Honest Significant Difference method were used for statistical analysis. RESULTS: The construct with the greatest resistance was ASIIBT. Its resistance was statistically higher compared to the IS technique (p = 0.001). Resistance compared to the SA technique was not statistically significant (p = 0.123), although in seven cases ASIIBT resisted more than 50 cycles at 200 N, while the SA technique reached 50 cycles at 200 N in just two cases. During cyclic loading, each specimen failed at the tenodesis site. CONCLUSIONS: ASIIBT showed higher failure loads compared with IS and SA. Better construct performance of ASIIBT is due to greater absorption of distension forces which may improve final tenodesis healing. Also, the absence of an implant lowers additional costs and the chances for postoperative complications may be decreased significantly.

Modified pre-curved patellar basket plate, reconstruction of the proper length and position of the patellar ligament--a biomechanical analysis.

Biomechanical properties of basket plate fixation for fracture dislocation in the distal part of the patella were studied on 22 fresh-frozen lower extremities (human cadaveric knees). The patella and the patellar ligament with the proximal tibia were removed. A comminuted fracture of the distal part of the patella was created with a chisel. The fractured patella, patellar ligament and tibial tuberosity of each specimen were fixed with a basket plate and mounted into the jaws of the testing machine. The measured load to failure was 421.66+/-45.90 N, which is approximately 70% higher than the results in other studies. The results of the measurements verified the results of finite element analysis. The modified precurved patellar basket plate developed in this study showed improved performance compared to the pre-existing fixation methods.

Simple and safe arthroscopic placement and removal of cannulated screw and washer for fixation of tibial avulsion fracture of the anterior cruciate ligament.

Avulsion of the tibial insertion of the anterior cruiciate ligament can be managed by arthroscopic reduction and fixation. Anterograde and retrograde fixation with screws has been reported. Anterograde fixation using cannulated screws is technically less demanding and allows for stable fixation even with thin fragments. Additional use of a washer affords safe fixation of comminuted avulsion fractures. Removal of the screw and washer is mandatory but sometimes problematic. A simple and safe technique of arthroscopic placement and removal of a screw and washer used for fixation of an avulsion fracture of the tibial insertion of the anterior cruiciate ligament is presented. The same technique can be used for placement and removal of a cannulated screw and washer used in other joints.