In the JournalsFrom OT Europe

Better survival, fewer manipulations found with fixed vs mobile bearing TKA

Patients who underwent total knee arthroplasty with a fixed bearing component experienced better implant survival with respect to revision for any reason and a lower number of manipulations than patients who had a mobile bearing procedure, according to study results.

Researchers randomly assigned 146 patients undergoing total knee arthroplasty (TKA) to receive either a fixed or mobile bearing component. Patients in the fixed bearing group were also randomly assigned to receive either a normal or a deep dish insert, while patients in the mobile bearing group were randomly assigned to receive either a rotating or a rotating/translating insert.

Primary outcome parameters included knee function and walking ability measured by the Knee Society Clinical Rating Scale. Researchers performed gait analysis at baseline and at 1 year and 5 years follow-up, and measured quality of life before surgery and at 1 year and 5 years follow-up.

Results showed comparable knee scores and function scores between the fixed bearing and mobile bearing groups and between the normal dish and deep dish groups. Researchers also found comparable measurements of single support time of the affected leg and the ratio in all groups. Between baseline and follow-up measurements, mental scores showed minimal difference, according to study results. Researchers noted one revision in the fixed bearing group and six revisions in the mobile bearing group. Overall, the fixed bearing group had a survival of 99.2% vs. 94.7% in the mobile bearing group. According to Kaplan-Meier curves, time to revision due to any reason over time was significantly different. Although Kaplan-Meier analysis showed no significant differences in time to manipulations between either bearing type or insert type, the rotation/translating insert appeared to have a greater manipulation rate. – by Casey Tingle

Disclosures: Fransen reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.

Patients who underwent total knee arthroplasty with a fixed bearing component experienced better implant survival with respect to revision for any reason and a lower number of manipulations than patients who had a mobile bearing procedure, according to study results.

Researchers randomly assigned 146 patients undergoing total knee arthroplasty (TKA) to receive either a fixed or mobile bearing component. Patients in the fixed bearing group were also randomly assigned to receive either a normal or a deep dish insert, while patients in the mobile bearing group were randomly assigned to receive either a rotating or a rotating/translating insert.

Primary outcome parameters included knee function and walking ability measured by the Knee Society Clinical Rating Scale. Researchers performed gait analysis at baseline and at 1 year and 5 years follow-up, and measured quality of life before surgery and at 1 year and 5 years follow-up.

Results showed comparable knee scores and function scores between the fixed bearing and mobile bearing groups and between the normal dish and deep dish groups. Researchers also found comparable measurements of single support time of the affected leg and the ratio in all groups. Between baseline and follow-up measurements, mental scores showed minimal difference, according to study results. Researchers noted one revision in the fixed bearing group and six revisions in the mobile bearing group. Overall, the fixed bearing group had a survival of 99.2% vs. 94.7% in the mobile bearing group. According to Kaplan-Meier curves, time to revision due to any reason over time was significantly different. Although Kaplan-Meier analysis showed no significant differences in time to manipulations between either bearing type or insert type, the rotation/translating insert appeared to have a greater manipulation rate. – by Casey Tingle

Disclosures: Fransen reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.