Primary knee arthroplasty for osteoarthritis restores patients' health-related quality of life to normal population levels

Patients aged 80 years and older have an equal improvement in joint-specific outcome health related quality of life and level of satisfaction when compared to those aged 65-75 years old undergoing knee arthroplasty

AIMS

To assess functional outcomes, health-related quality-of-life (HRQoL), and satisfaction at 1-year following knee arthroplasty (KA) in patients aged ≥80 compared to those aged 65-75-years when adjusting for confounding factors.

METHODS

A single-centre retrospective cohort study was performed using data from 2010 to 2020. Demographic data, length of stay (LOS), preoperative and 1-year postoperative EuroQol (EQ-5D and EQ-VAS), Oxford Knee Score (OKS) and Outcome Satisfaction (OS) were recorded. Patients aged ≥80 were compared to a control group aged 65-75-years. Regression analyses were performed to assess the independent association of age group after adjusting for confounding factors.

RESULTS

Compared to the 65-75-year group (n = 7525) the ≥80-year group (n = 2966) had greater comorbidity (p < 0.001), worse preoperative OKS (p < 0.001) and EQ-VAS (p = 0.012). Postoperatively both groups had clinically and statistically significant (p < 0.001) improvements in OKS, EQ-5D and EQ-VAS. There was no difference in improvement in OKS (mean difference (p = 0.081) or OS (p = 0.203) between the groups. However, the ≥80-year group had less of an improvement in EQ-5D (p = 0.047) and EQ-VAS (p = 0.007), but these were not clinically meaningful. However, when adjusting for confounding variables there were no differences in improvement in OKS (p = 0.372), EQ-5D (p = 0.703), and EQ-VAS (p = 0.283), or OS (p = 0.829) between the groups. The ≥80-year group was independently associated with a longer LOS (95% CI 0.3-0.8, p < 0.001) when adjusting for confounding factors.

CONCLUSIONS

Patients ≥80-years had clinically significant improvements in joint-specific outcome and HRQoL and OS equal to those aged 65-75-years following KA. The ≥80 group had a longer mean LOS of half a day.

The current role of CT in total knee arthroplasty

Advanced 3D imaging and CT-based navigation have emerged as valuable tools to use in total knee arthroplasty (TKA), for both preoperative planning and the intraoperative execution of different philosophies of alignment. Preoperative planning using CT-based 3D imaging enables more accurate prediction of the size of components, enhancing surgical workflow and optimizing the precision of the positioning of components. Surgeons can assess alignment, osteophytes, and arthritic changes better. These scans provide improved insights into the patellofemoral joint and facilitate tibial sizing and the evaluation of implant-bone contact area in cementless TKA. Preoperative CT imaging is also required for the development of patient-specific instrumentation cutting guides, aiming to reduce intraoperative blood loss and improve the surgical technique in complex cases. Intraoperative CT-based navigation and haptic guidance facilitates precise execution of the preoperative plan, aiming for optimal positioning of the components and accurate alignment, as determined by the surgeon's philosophy. It also helps reduce iatrogenic injury to the periarticular soft-tissue structures with subsequent reduction in the local and systemic inflammatory response, enhancing early outcomes. Despite the increased costs and radiation exposure associated with CT-based navigation, these many benefits have facilitated the adoption of imaged based robotic surgery into routine practice. Further research on ultra-low-dose CT scans and exploration of the possible translation of the use of 3D imaging into improved clinical outcomes are required to justify its broader implementation.

Mako versus ROSA: comparing surgical accuracy in robotic total knee arthroplasty

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, posterior condylar offset and tibial slope. This was a retrospective review of a prospectively collected data of the initial 50 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 with regards to joint line height (JLH), patella height (PH), tibial slope (TS) and posterior condylar offset (PCO). Mean difference between pre- and post-operative radiographs using the ROSA knee system of joint line height was 0.47 mm (SD 0.95) posterior condylar offset 0.16 mm (SD 0.76), tibial slope 0.9 degrees (SD 1.6) and patella height 0.01 (SD 0.05). Mean difference using the MAKO knee system of joint line height was 0.26 (SD 1.08), posterior condylar offset -0.26 mm (SD 0.78), tibial slope 1.8 degrees and patella height 0.03. No significant difference was demonstrated between the accuracy of component positioning of the ROSA or MAKO knee systems. Our study is the first study to compare the accuracy of the ROSA and MAKO knee systems in total knee arthroplasty. Both systems are highly accurate in restoring native posterior condylar offset, joint line height, tibial slope and patella height in TKA with no significant difference demonstrated between the two groups.