Percutaneous antegrade scaphoid screw placement: a feasibility and accuracy analysis of a novel electromagnetic navigation technique versus a standard fluoroscopic method.

BACKGROUND: Central screw positioning in the scaphoid provides biomechanical advantages. METHODS: A prospective randomized study of six fluoroscopically guided and six electromagnetically navigated screw (ENS) placements was performed on human cadavers. Accuracy of screw position was determined. Intraoperative fluoroscopy exposure times, readjustments of drilling directions, complete restarts and complications were documented. RESULTS: The ENS method provided a mean time benefit of 7.34 min compared with the standard method and the mean screw length ratio (SLR coronar: ENS 0.96 ± 0.04 mm, SFF: 0.92 ± 0.04 mm, P = 0.065; SLR sagittal: ENS 0.98 ± 0.02 mm, SFF: 0.91 ± 0.04 mm, P = 0.009) and the screw axis deviation angle (AD coronar: ENS 3.33 ± 2.34°, SFF: 10.33 ± 2.58°, P = 0.002; AD sagittal: ENS 2.83 ± 0.98°, SFF: 11.00 ± 6.16°, P = 0.002) were lower. Using the electromagnetic navigation procedure no drilling readjustments or restarts were required, no cortical breach occurred. CONCLUSIONS: Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy, less complications, required less operation and radiation exposure time.

[Surgical treatment of posterior shoulder dislocation: importance of arthroscopy]. / Operative Versorgung der posterioren Schulterluxation: Stellenwert der Arthroskopie.

OBJECTIVE: Posterior dislocations of the shoulder represent a rare injury with frequently occurring soft tissue and/or bony concomitant lesions such as the reverse Hill-Sachs lesion and the dorsal labrum tear. For the combination of these injuries, no evidence-based therapeutic recommendations exist. AIM OF STUDY: Reflecting on two clinical cases and the current literature data, options for the treatment of combined osseous and soft tissue injuries due to posterior dislocation of the shoulder are presented. METHODS: We report two cases of fresh traumatic first-time posterior dislocations that were each explored arthroscopically and subsequently operated using an open technique. In the first case, we performed refixation of the labrum, followed by open osteosynthesis with bone substitution. Treatment of the second case included diagnostic arthroscopy and - after a frustrating attempt to elevate the defect in an arthroscopically assisted retrograde technique - open reconstruction of the humeral head with an allograft. RESULTS: In both cases good clinical outcomes with Constant scores of 79 and 86 points at the 16- and 12-month follow-ups, respectively, were achieved. Radiologically complete integration of the used materials was found. CONCLUSION: These cases show that for the operative treatment of fresh, traumatic posterior shoulder dislocation, it is useful to explore the joint arthroscopically to identify concomitant injuries of the labrum and if necessary treat them. The bony pathology of the humeral head can subsequently be addressed in an open technique, whereby the appropriate treatment should be chosen based on the size of the defect.