Intraoperative 3D-Rekonstruktion des PMMA-Köchers zur computerassistierten Revisionshüftendoprothetik auf Basis von 2D-Röntgen-Bildgebung

Clinical experience with computer navigation in revision total hip arthroplasty

The biomechanically and anatomically correct placement of hip prostheses components is the main challenge in revision hip arthroplasty. The orientation of the cup and stem with the restoration of leg length, offset and hip centre is hampered by the defect situations frequently present. In primary hip arthroplasty, it has been demonstrated that the components can be accurately positioned using computer-navigated procedures. However, such procedures could also be of considerable benefit in revision hip arthroplasty. Systems that not only detect anatomical landmarks using pointers but also use image data for referencing may provide a possible solution for the defect situation. Literature about navigation in revision arthroplasty is very rare. This article comprises general considerations on this subject and presents our experience and possible clinical applications.

Survivorship analysis in patients with periosteal chondrosarcoma

To investigate outcome and identify prognostic factors, we retrospectively reviewed 24 consecutive patients with periosteal chondrosarcomas. There were 17 males and seven females with a mean age of 37.6 years (range, 15-73 years). The femur was involved in 12 patients, the proximal humerus in five, the tibia in two, and the distal fibula, ilium, pubis, metatarsal, and rib in one patient each. The mean greatest dimension of the lesions was 8.1 cm (range, 1.5-27 cm). Based on the histologic pattern, there were 18 Grade 1 tumors and six Grade 2 tumors. All patients were treated surgically. Two patients had intralesional excisions, five patients had marginal excisions, and 17 patients had wide resections. With a mean followup of 17 years (range, 28 months-47 years), seven of 24 patients (29%) had one or more local recurrences. The 5-year local recurrence-free survival was less in patients treated with intralesional or marginal excisions (25%) than for patients treated with wide resections (93%). At the latest followup, six of 24 patients (25%) had died of pulmonary metastases. The overall 5-year metastasis-free survival was 83%. The 5-year metastasis-free survival was less for patients with Grade 2 tumors (50%) than for patients with Grade 1 tumors (94%).

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.