Staged BiCompartmental Knee Arthroplasty has Greater Functional Improvement, but Equivalent Midterm Survivorship, as Revision TKA for Progressive Osteoarthritis After Partial Knee Arthroplasty.

BACKGROUND: Progressive arthritis in the unresurfaced compartments of the knee is one failure mode after partial knee arthroplasty (PKA). While progressive arthritis after PKA is typically treated with revision to TKA (rTKA), staged bicompartmental knee arthroplasty (sBiKA) -the addition of another PKA - is an alternative. This study compared outcomes of sBiKA and rTKA for progressive arthritis after PKA. METHODS: A retrospective comparative study of non-consecutive cases at four institutions were performed in patients with an intact PKA, without loosening or wear, who underwent sBiKA (n = 27) or rTKA (n = 30), for progressive osteoarthritis. Outcomes studied were new Knee Society Function and Objective Scores (KSSF, KSSO), KOOS, Jr., ROM, operative times, length of stay, complication rates and the need for reoperations. RESULTS: Mean time to conversion was 7.4 ± 6 years for sBiKA and 9.7 ± 8 for rTKA, P = .178. Patient demographics and pre-operative outcomes were similar among cohorts. At an average of 5.7 ± 3 (sBiKA) and 3.2 ± 2 years (rTKA), KOOS, Jr. significantly improved, P < .001, by an equivalent amount. Post-operative KSSO and KSSF were significantly higher in the sBiKA cohort, respectively, (90.4 ± 10 vs 72.1 ± 20, P < .001) and (80.3 ± 18 vs 67.1 ± 19, P = .011). sBiKA patients had significantly greater improvement in KSSO (30.7 ± 33 vs 5.2 ± 18, P = .003). One sBiKA patient underwent reoperation for continued pain. CONCLUSION: SBiKA has equivalent survivorship, but greater improvement in functional outcomes as rTKA at short to midterm follow-up. Given the shorter operative times and length of stay, sBiKA is a safe and cost-effective alternative to rTKA for progressive osteoarthritis following PKA. Nevertheless, further follow-up is necessary to determine whether sBiKA is a durable option.

Total Hip and Knee Revisions are Really Outpatient Procedures? Implications of the Removal From the Inpatient Only List.

BACKGROUND: In 2021, the Centers for Medicare and Medicaid Services (CMS) removed over 200 procedures from the Inpatient Only (IPO) list including revision total hip (THA) and total knee arthroplasties (TKA). The purpose of this study is to determine if some revision TKA and THA procedures may be appropriate for outpatient status. METHODS: We reviewed a consecutive series of 1026 revision THA and TKA patients at our tertiary academic institution from 2015 to 2020. An outpatient procedure was defined as a length of stay of <2 midnights. We queried our prospectively collected arthroplasty database and compared demographics, comorbidities, surgical indication, type of procedure, discharge disposition, readmissions, and complications between the outpatient and inpatient groups. RESULTS: There were only 166 revision patients (16%) who met outpatient criteria. Revision THA outpatients were more likely to have a head and liner exchange (49% vs 25%, P < .001) and an indication of instability (93% vs 44%, P < .001). Revision TKA outpatients were more likely to have an isolated liner exchange (34% vs 14%, P < .001) and have an indication of instability (67% vs 25%, P < .001). Patients undergoing a revision for infection and aseptic loosening were more likely to require an inpatient stay than other revision indication (P < .05). CONCLUSION: The vast majority of revision TKA and THA patients met CMS inpatient criteria. In addition to a projected decrease in facility reimbursement, concerns exist for the safety of early discharge and access to care for these complex patients if CMS removes all revisions from the Inpatient Only list.