There is increasing adoption of robotic surgical technology in Total Knee Arthroplasty - The ROSA® knee system can be used in either image-based mode (using pre-operative calibrated radiographs) or imageless modes (using intra-operative bony registration). The Mako knee system is an image-based system (using a pre-operative CT scan). This study aimed to compare surgical accuracy between the ROSA and Mako systems with specific reference to Joint Line Height, Patella Height and Posterior Condylar Offset. This was a retrospective review of a prospectively-maintained database of the initial 100 consecutive ROSA TKAs and the initial 50 consecutive Mako TKAs performed by two high volume surgeons. To determine the accuracy of component positioning, the immediate post-operative radiograph was reviewed and compared with the immediate pre-operative radiograph. Patella height was assessed using the Insall-Salvati ratio.Abstract
Introduction
Methodology
There is growing interest in the use of robotic Total Knee Arthroplasty (TKA) to improve accuracy of component positioning. This is the first study to investigate the radiological accuracy of implant component position using the ROSA® knee system with specific reference to Joint Line Height, Tibial Slope, Patella Height and Posterior Condylar Offset. As secondary aims we compared accuracy between image-based and imageless navigation, and between implant designs (Persona versus Vanguard TKA). This was a retrospective review of a prospectively-maintained database of the initial 100 consecutive TKAs performed by a high volume surgeon using the ROSA® knee system. To determine the accuracy of component positioning, the immediate post-operative radiograph was reviewed and compared with the immediate pre-operative radiograph with regards to Joint Line Height, Tibial Slope, Patella Height (using the Insall-Salvati ratio) and Posterior Condylar Offset.Abstract
Introduction
Methodology
Comparison of the safety and efficacy of Bilateral Simultaneous Total Hip Arthroplasty (BSTHA) with that of staged (SgTHA) and unilateral (UTHA) was conducted using DerSimonian–Laird heterogeneity meta-analysis. A review of the English-language literature identified 23 citations eligible for inclusion. A total of 2063 bilateral simultaneous THR patients were identified. Meta-analysis of homogenous data revealed that there were no statistically significant differences between rates of thromboembolic events (p=0.268 and p=0.365) and dislocation (p=0.877) when comparing staged or unilateral with bilateral simultaneous THR procedures. A systematic analysis of heterogenous data demonstrated that mean length of hospital stay was shorter after bilateral simultaneous THR. Blood loss was reduced after bilateral simultaneous THR in all studies except for one, and surgical time was not different between groups. This procedure was also found to be economically and functionally efficacious when performed by experienced surgeons in specialist centres.
In selected patients in-cement revision of the total hip arthroplasty components is an attractive option. Recommended roughening of the primary mantle surface remains controversial. Aim of the study was to investigate the influence of the cement surface roughening on the strength of bilaminar cement interface. Flat, laboratory model of bilaminar cement interface was used. Prior to its creation, modeled primary mantle surface was machined to the roughness of either smooth surface observed after removal of a highly polished stem (Ra=200nm) or that following roughening (Ra=5μm). Two viscosities of interfering fluids (water and bone marrow) were also used. 6 variants (smooth or rough, both stained with water, bone marrow or with no fluid) with 7 repeats were exposed to single shear to failure. No significant difference in resistance to shear was observed between the groups with dry smooth (16.82MPa) and rough surfaces (16.96MPa), and those stained with large volume of low viscosity fluid. In the presence of water, roughening did not significantly influence the interface (smooth – 17.04MPa and rough – 16.25MPa respectively). In the smooth variant with large volume of viscous fluid, ultimate stress value dropped to 5.53MPa, and 9.87MPa in the roughened group with the same amount of viscous fluid (p<
0.05). Extra roughening may offer some benefit when performing in-cement revision in the presence of large volume of viscous fluid only though in-cement revision would not be then recommended. In the presence of low viscosity fluids (blood, irrigation fluid) benefit of roughening is dubious.
Periprosthetic femoral fractures around total knee arthroplasty present a challenge in octogenarians with advanced osteoporosis. We describe a salvage technique combining retrograde intramedullary nailing augmented with polymethylmethacrylate (PMMA) cement in five patients followed up for a median time of 12 months. The nail/cement construct bridges the femoral canal tightly and behaves like a stemmed cemented revision component. All patients had an uncomplicated recovery and returned to their pre-injury functional status within four months. This procedure does not disrupt the soft tissue envelope facilitating periosteal callus formation, is easy to perform and permits immediate full range of movement. When standard retrograde nailing or plating alone is inadequate in maintaining severely osteoporotic fracture reduction in octogenarians unfit for lengthy procedures, nailed cementoplasty is proposed as a salvage procedure.
