Navigation Improves the Survival Rate of Mobile-Bearing Total Knee Arthroplasty by Severe Preoperative Coronal Deformity: A Propensity Matched Case–Control Comparative Study

Abstract

The primary hypothesis of this study was that the survival rate over 10 years of total knee arthroplasties (TKAs) implanted with a navigation system was superior to that of TKAs implanted with a conventional technique. The secondary hypothesis was that the severity of the initial coronal deformity had a negative influence on the survival rate. A national, multicentric, retrospective study was performed in France, including eight university or private centers with high volumes in knee surgery. Cases operated on with either a conventional (control group) or a navigated (study group) technique were matched after calculating the propensity score using the logistic regression technique. All patients were contacted after 10 years or more to determine the survival of the TKA. The need for date and cause of revision were noted. The primary end point of the study was the occurrence of a revision for any mechanical reason. Survival curves were calculated using the Kaplan–Meier's technique, with the primary criterion as end point. The influence of the implantation technique was analyzed by a log-rank test at a 5% level of significance. The influence of severity of the preoperative coronal deformity was analyzed using the same technique. A total of 513 cases were included in each group. The survival rates after 13 years were 96.5% in the study group and 92.9% in the control group (not significant). There was no significant difference between both groups for the survival rates after 13 years for small deformity (96.0 vs. 97.0%), but the difference was significant for large deformity (97.0 vs. 89.0%, p = 0.04). The results suggest that the use of a navigation system, allowing a more consistent correction of the preoperative coronal deformity, thus allows a better long-term prosthetic survival in cases with a large initial coronal deformity. A navigation system should be routinely used in cases of initial coronal deformity greater than or equal to 10 degrees, as conventional techniques do not routinely provide satisfactory axial correction in these difficult cases.

Can Technology Assistance be Cost Effective in TKA? A Simulation-Based Analysis of a Risk-prioritized, Practice-specific Framework

“…The cost-effectiveness of TA-TKA systems has been a controversial topic in orthopaedic surgery. Previous studies aiming to evaluate the net benefit or cost of implementing TA-TKA systems have not demonstrated improvements in implant survivorship in the general population of patients undergoing TKA [13, 15, 18, 26-28, 31, 32, 39, 40, 62]. The simulation results presented above suggest that technology assistance cannot generally be considered to be cost effective for application across the board in a general clinical population.…”

“…Studies have argued that many revision procedures (approximately 70% [1, 11, 48]) are related to mechanical aspects of the procedure that are under the surgeon’s control, such as implant alignment. To reduce outliers in making bone cuts and placing implants, robotic, navigated and patient-specific instrumentation (PSI) systems have been introduced with the goal of improving the precision of bone cuts and implant alignment [13, 15, 18, 26-28, 31, 32, 39, 41, 62].…”

“…The use of technology-assisted TKA (TA-TKA) remains controversial, however, because the best available evidence has shown that these technologies generally have higher costs than conventional TKA surgeries (as high as USD 6000 per procedure from the payer perspective [3]) and increased operating times (up to approximately 25 minutes per procedure [50]), and a number of randomized controlled trials have found no significant advantages in terms of implant survivorship or patient function in general populations of patients undergoing TKA [13, 15, 18, 26-28, 31, 32, 39, 41, 62]. Nonetheless, because there is some evidence that improved control over implant alignment could reduce revision risk [34], we believe it may be possible that TA-TKA could prove to be cost effective when applied more selectively to subpopulations of patients who are known to be at an elevated risk for premature revision because of patient-specific factors such as age at index surgery, BMI, and gender.…”

How Large a Study Is Needed to Detect TKA Revision Rate Reductions Attributable to Robotic or Navigated Technologies? A Simulation-based Power Analysis

“…For example, leaving the femoral component in excessive varus or valgus alignment leads to elevated revision rates [26]. To reduce such outliers, robotic and navigated TKA procedures (collectively referred to herein as technology-assisted TKA [TA-TKA]) have been introduced to improve the precision of bone cuts and implant alignment [4, 9, 11, 12, 14, 18-25, 28-31, 33, 35, 36]. Although these innovations in surgical navigation have improved the accuracy of implant placement, most comparative outcome studies have not demonstrated clear reductions in revision rates [9, 11, 12, 14, 18-25, 28-31, 33, 35, 36].…”

“…To reduce such outliers, robotic and navigated TKA procedures (collectively referred to herein as technology-assisted TKA [TA-TKA]) have been introduced to improve the precision of bone cuts and implant alignment [4, 9, 11, 12, 14, 18-25, 28-31, 33, 35, 36]. Although these innovations in surgical navigation have improved the accuracy of implant placement, most comparative outcome studies have not demonstrated clear reductions in revision rates [9, 11, 12, 14, 18-25, 28-31, 33, 35, 36]. One retrospective trial [4] reported a significant difference but had a high loss to follow-up rate (56%) and no controls for preoperative patient demographics, with statistically significant differences in age at the index surgery and BMI between the conventional group and the navigated group, likely resulting in a higher risk of revision for the conventional group simply based on these patient-specific factors (younger age at surgery and increased BMI [5, 7]).…”