Proximity of the posterior cruciate ligament insertion to the popliteal artery as a function of the knee flexion angle: implications for posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to determine if an optimal knee flexion angle existed that would minimize the risk of neurovascular injury from the passage of transtibial hardware during posterior cruciate ligament (PCL) reconstruction. TYPE OF STUDY: Cadaveric. MATERIALS AND METHODS: Fourteen fresh-frozen cadaveric knees were mounted in a Plexiglas apparatus that could be set at 5 different knee flexion angles (0 degrees, 45 degrees, 60 degrees, 90 degrees, and 100 degrees ) while joint distention was maintained. Each knee underwent magnetic resonance imaging in the axial and sagittal planes at each of the 5 flexion angles to determine the distance between the PCL tibial insertion and popliteal artery. RESULTS: The mean distance, over all 5 flexion angles, between the PCL insertion and the popliteal artery in the axial plane was 7.6 mm, whereas the mean distance in the sagittal plane was 7.2 mm. There was a significant increase in distance with progressive flexion in both planes. Maximum mean distances were noted at 100 degrees of flexion in both the axial (9.9 mm) and sagittal (9.3 mm) planes. An artificial line mimicking the path of a transtibial drill passed through the popliteal artery in 10 of 10 cases at the 0 degrees, 45 degrees, 60 degrees, and 90 degrees angles, and in 6 of 10 cases at the 100 degrees angle. CONCLUSIONS: The results of this study suggest that increasing knee flexion reduces, but does not completely eliminate, the risk of arterial injury during arthroscopic PCL reconstruction.

Complications of buttress plate stabilization of cervical corpectomy.

STUDY DESIGN: A retrospective analysis of 14 patients treated with cervical corpectomy and buttress plate fixation. OBJECTIVES: To determine the complications of buttress plate fixation following multilevel cervical corpectomies. SUMMARY OF BACKGROUND DATA: Buttress plate fixation of multilevel cervical corpectomy has recently been reported. Biomechanical data suggests that it is preferable to long plates spanning the entire corpectomy site. There are no clinical studies that have specifically addressed the complications of this type of plate fixation. METHODS: The records and radiographs of all patients who had undergone cervical buttress plate fixation following anterior cervical corpectomy for myelopathy were independently reviewed. Twelve of the patients had three-level corpectomies and two had two-level corpectomies. All patients had placement of a short plate at the inferior end of the construct with sufficient overhang to act as a buttress against graft extrusion. Three patients underwent posterior cervical fusion in addition to the anterior procedure. RESULTS: Graft extrusion. One patient had complete graft extrusion on the third post-operative night. A second patient who had undergone circumferential fusion had minimal plate dislodgement secondary to graft settling. Pseudarthrosis. Three patients had pseudarthroses. Two of these required revision posterior surgery. Neurologic. None of the patients suffered neurologic complications. With the exception of the one patient who died, the rest of the patients all improved by at least one Nurick grade. CONCLUSION: The most catastrophic complication in the present series was plate dislodgement causing airway compromise and eventually resulting in death. Surgeons who utilize these types of buttress plates without additional posterior instrumentation should be aware of the potential complications of buttress plate fixation.