In properly chosen patients, cementless total knee arthroplasty has achieved success rates equal to cemented designs. The initial variable results of early cementless total knee replacements were a function of design, surgical technique and patient selection. Important design considerations that have enhanced biologic ingrowth include the use of commercially pure titanium with optimal pore size and porosity, and avoidance of porous-coated stems and plugs that cause stress shielding of the bone-implant interface. Factors in surgical technique that enhance bone ingrowth include precise bone cuts that maximise bone-implant contact, and the application of autogenous bone slurry to cut surfaces. Additional factors are restoration of normal alignment, appropriate ligament balance, and the reproduction of the patient's native tibial slope in order to prevent tibial component subsidence. Young and active patients are ideal biological hosts for the use of cementless knee fixation. Their relatively dense cancellous bone and rich blood supply provides for robust purchase for initial fixation and the appropriate milieu for long-term biologic fixation. With increasing life expectancy, this more durable interface is desirable. With avoidance of porous-coated stems and pegs and prevention of fibrous tissue attachment, potential future revisions are more bone-sparing relative to methylmethacrylate fixation. Numerous reports, as well as the authors’ published 10- to 14-year results, demonstrate that cementless fixation in appropriately selected patients provides results comparable to cemented TKA, with the advantage of conserving bone stock and eliminating the potential problems of cement fixation

In properly chosen patients, cementless total knee arthroplasty has achieved success rates equal to cemented designs. The initial variable results of early cementless total knee replacements were a function of design, surgical technique and patient selection. Important design considerations that have enhanced biologic ingrowth include the use of commercially pure titanium with optimal pore size and porosity, and avoidance of porous-coated stems and plugs that cause stress shielding of the bone-implant interface. Factors in surgical technique that enhance bone ingrowth include precise bone cuts that maximize bone-implant contact, and the application of autogenous bone slurry to cut surfaces. Additional factors are restoration of normal alignment, appropriate ligament balance, and the reproduction of the patient's native tibial slope in order to prevent tibial component subsidence. Young and active patients are ideal biological hosts for the use of cementless knee fixation. Their relatively dense cancellous bone and rich blood supply provides for robust purchase for initial fixation and the appropriate milieu for long-term biologic fixation. With increasing life expectancy, this more durable interface is desirable. With avoidance of porous-coated stems and pegs and prevention of fibrous tissue attachment, potential future revisions are more bone-sparing relative to methylmethacrylate fixation. Numerous reports, as well as the authors' published 10- to 14-year results, demonstrate that cementless fixation in appropriately selected patients provides results comparable to cemented TKA, with the advantage of conserving bone stock and eliminating the potential problems of cement fixation

Background. Currently, stailess steel, titanium and carbon-fiber reinforced polyetheretherketone (CF-PEEK) plates are available for the treatment of distal radius fractures. Since the possibility to create a less rigid fixation may represent an advantage in case of ostheoporotic or poor quality bone, the aim of this study is to compare the biomechanical properties of these three materials in terms of bending stiffness with a single static load and after cyclical loading, simulating physiologic wrist motion. Materials and Methods. Three volar plating systems with fixed angle were tested: Zimmer stainless steel volar lateral column (Warsaw, IN); Hand Innovations titanium DVR (Miami, FL); Lima Corporate CF-PEEK DiPHOS-RM (San Daniele Del Friuli, Udine, Italy). For each type of plate tested four right synthetic composite bone radii were used. An unstable, extraarticular fracture was simulated by making an 8 mm gap with a saw starting 12 mm proximal to the articular surface of the radius on the distal radio-ulnar joint side. The osteotomies were made perpendicular to the long axis of the bone to allow for a consistent fracture gap on the dorsal and volar sides of the radius. Plates were implanted using all the distal and proximal fixation holes [Fig. 1]. Each synthetic radius model was potted in methylmethacrylate and tested in a bi-axial servo-hydraulic test frame (MTS Minibionix 858, universal testing machine) for load to failure by advancing a cobalt chrome sphere centered over the articular surface at a constant rate of displacement of 5 mm/min. The sphere was advanced until the construct failed or the dorsal edges of the fracture met. The resultant force was defined as bending stiffness pre fatigue. Three constructs for each plate were then dynamically loaded for 6000 cycles of fatigue at a frequency of 10Hz, with a load value corresponding to the 50% of the previously calculated bending strength. Finally, the constructs were loaded to failure, measuring the bending stiffness post fatigue. Results. All fracture constructs survived all phases of the cyclic loading testing. The mean bending stiffness pre fatigue was higher for the Zimmer plate (155.23±1.91 N/mm), in comparison to Hand Innovations (138.67±4.72 N/mm), and DiPHOS-RM (124.75±3.60 N/mm) [Fig. 2]. After cyclic loading, stiffness increased significantly of a mean 24% for the Zimmer plate (190.42±4.33 N/mm); 33% for the Hand Innovations (186.57±1.71 N/mm); and 18% for the DiPHOS-RM (146.28±1.52 N/mm) [Fig. 2–3]. Conclusions. CF-PEEK plate is less stiff than stainless steel and titanium plates, with an elastic modulus more similar to bone as well as the ability to withstand prolonged fatigue strain. From these preliminary data it might be assumed that the CF-PEEK plates could provide a sufficiently stable osteosynthesis, flexible enough to unload the implant-bone interface, minimising peak stresses at the bone- implant interface, making them particularly suitable for fracture fixation in osteoporotic patients. A proper patient selection (avoiding incompliant or non collaborative) should be performed using CF-PEEK plates to avoid possible implant breakage consequent to a fall or a second trauma on the injuried wrist until the complete fracture healing. For any figures or tables, please contact authors directly (see Info & Metrics tab above).