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

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

No difference in 13-year survival after medial pivot or central pivot mobile bearing total knee arthroplasty. A propensity matched comparative analysis.

The present study was designed to evaluate the long-term results (more than 10 years) of mobile bearing total knee arthroplasty (TKA) and to compare the survival of medial pivot axis (MPA) and central pivot axis (CPA) TKAs. The primary hypothesis was that the 10- to 15-year survival rate of MPA TKAs will be better than CPA TKAs. A national, multicenter, retrospective study was performed in France. In this case-control design, 1154 TKAs were paired into the CPA group (control group: 577 cases) and MPA group (study group: 577 cases) based on a logistic regression analysis of age, gender, body mass index and severity of the coronal deformity, defining the propensity score for each case. Final survival information follow-up was obtained for 946 cases (82%). There was no significant difference between the control and study groups for any baseline data. Twenty-two prosthetic revisions (2%) were performed for mechanical reasons during the follow-up period. There was no significant difference between the 13-year survival rates of CPA (98%) and MPA (97%) TKAs. There was no significant difference between groups in their final Oxford and Knee Society scores. Our findings do not support the assumption that medialization of the pivot axis of a mobile bearing TKA improves clinical results or survival. Level III