Primary stability of a robodoc® implanted anatomical stem versus manual implantation

• Published in: Clinical biomechanics (Bristol) Vol. 19; no. 2; pp. 123 - 129
• Main Authors: Nogler, Michael, Polikeit, Anne, Wimmer, Cornelius, Brückner, Andreas, Ferguson, Stephen J, Krismer, Martin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2004
• Subjects: Adult; Aged; Arthroplasty, Replacement, Hip - methods; Biomechanical Phenomena; Cadaver; Computer-assisted orthopaedic surgery (CAOS); Female; Femur - surgery; Hip Prosthesis; Humans; Joint Instability - prevention & control; Male; Middle Aged; Primary stability; Probability; Prosthesis Design; Prosthesis Fitting - methods; Range of Motion, Articular - physiology; robodoc; robotics; Sensitivity and Specificity; Stress, Mechanical; Surgery, Computer-Assisted - methods; Total hip replacement; Weight-Bearing; Total hip replacement; Computer-assisted orthopaedic surgery (CAOS); Primary stability; robodoc
• ISSN: 0268-0033; 1879-1271
• DOI: 10.1016/j.clinbiomech.2003.09.010

Objective. To assess the initial stability of anatomical stems implanted in manually broached femoral cavities compared with that assessed in cavities milled with the robodoc ® system. Design. The bone-prosthesis interface motion was measured in matched pairs of cadaveric femora to assess the initial stability of anatomical stems implanted with two different implantation techniques. Background. The high costs of surgical robots and the increased perioperative efforts associated with their use can only be justified if measurable benefits for patients can be achieved. Increased initial stability of the stem as an early indicator for better bone ongrowth would be such a benefit. Methods. Seven pairs of fresh frozen human cadaveric femora were used. One femur of each pair was randomly assigned to receive the robotic milling method; the other femur underwent manual broaching by an experienced surgeon. Initial micromotions of the anatomical stems were measured during simulated gait cycles with loads of ⩽1500 N, and both groups underwent matched-pair analysis. Results. High motion of the prostheses was found for both implantation techniques Conclusions. The robodoc ® system did not enhance the primary stability of the anatomical prosthesis compared with the manual broaching method. Relevance The initial stability of a femoral prosthesis may be an indicator of bone ongrowth and improved long-term fixation. Objective outcome measurements are needed to determine the effectiveness of the robotic milling method in achieving initial stability of implanted anatomic femoral stems.