OUTCOMES OF LINER EXCHANGE VERSUS COMPONENT REVISION FOR THE TREATMENT OF STIFFNESS FOLLOWING TOTAL KNEE ARTHROPLASTY

The optimal surgical management for stiffness post total knee replacement (TKA) remains controversial and there is a paucity of evidence evaluating the outcomes of liner exchange (LE) versus component revision (CR). The aim of this study was to compare the outcomes of revision TKA (rTKA) with arthrolysis and LE versus CR for the treatment of stiffness post TKA. Primary outcomes were achievement of a successful range of movement (ROM) and improvement in arc of motion (AOM). Secondary outcomes included survival free from all-cause and stiffness re-revision, as well patient-reported outcomes. We retrospectively reviewed our institutional database to identify all rTKA performed for stiffness in patients post primary TKA between 2005 and 2021. Patients with less than two-year follow-up, loose components, or infection were excluded. A total of 129 rTKA for stiffness were included; 91 (71%) LE and 38 (29%) CR. Mean patient age was 63.1, BMI was 30.6, and 60% were female. The mean follow-up was 8.5 years (range two-21). The LE and CR cohorts had similar patient age (p=0.83), BMI (p=0.99), sex (p=0.99), previous manipulation (p=0.45), time from primary TKA (p=0.14), and pre rTKA AOM (p=0.08). Achievement of a successful ROM was defined as flexion ≥ 90 degrees with extension deficit of ≤ 10 degrees at final follow-up. Primary ROM outcomes and the Forgotten Joint Score (FJS) were compared between LE and CR cohorts. Kaplan-Meier analysis was used to determine survival free from re-revision for the entire cohort and between cohorts. For the entire cohort, 69% (82) achieved a successful ROM post rTKA and the mean AOM improved (63.2 to 88.5, p < 0 .001). Achievement of a successful ROM post rTKA was similar for the LE (72%) and CR (62%) cohorts (p=0.29). The mean gain in AOM was also similar between the LE (24.9 degrees, range -65 to 70) and CR (25.4 degrees, range -40 to 70) cohorts (p=0.45). Seventeen (13%) patients underwent an all-cause re-revision. The 10-year all-cause re-revision free survival was 84.7% (SE 3.6%) for the entire cohort and similar between the LE (86.2%) and CR (81.1%) cohorts (p=0.55). There were 11 (9%) re-revisions for stiffness for the entire cohort. The survival from re-revision for stiffness was 90.2% (SE 2.9%) at 10-years for the entire cohort, and similar for the LE (91.6%) and CR (86.7%) cohorts (p=0.6). The mean FJS was 23.4 (range zero-91.7) at final follow-up and only 43.2% achieved a patient acceptable symptom state. The mean FJS was similar between cohorts (p=0.14), but the LE cohort achieved a higher proportion of acceptable symptoms than the CR cohort (56% vs. 10%, p=0.03). Revision TKA for stiffness resulted in modest gains in ROM and a reasonable 10-year re-revision free survival, however, functional outcomes and patient satisfaction were poor. LE resulted in similar achievement of a successful ROM, re-revision free survival, and FJS compared with CR, but a better acceptable symptom state. Our results suggest that when indicated, liner exchange is a reasonable option for the treatment of stiffness after TKA.