Short- to Midterm Outcomes of a Novel Guided-Motion Rotational Hinged Total Knee Arthroplasty

Hinged prostheses have been increasingly utilized in complex and revision total knee arthroplasty (TKA) cases requiring additional mechanical support and global stability. However, there is limited data detailing the outcomes of modern hinge designs in these procedures. The aim of this study is to report a minimum 2-year functional outcomes and survivorship of a novel-guided motion-hinged knee TKA system. A multicenter, retrospective cohort study was conducted on consecutive TKA patients between March 2013 and August 2017 with a novel-guided motion-hinged knee system. Demographics, change in range of motion (ΔROM), quality metrics, and implant survivorship were collected with a minimum of 2-year follow-up. Implant survival was analyzed by using the Kaplan-Meier method. Overall, 147 hinged knee cases (18 complex primaries and 129 revisions) were identified with an average follow-up duration of 3.8 ± 1.2 years. Patients presented with an average of 2.4 ± 1.6 prior knee surgeries, and 51 (34.7%) had a history of knee infections. The ROM improved postoperatively: Δ extension = 2 ± 1 degrees, Δflexion = 7 ± 3 degrees, Δtotal ROM = 9 ± 4 degrees. Kaplan-Meier survivorship analysis for implant revision at 2- and 5-year follow-up showed a survival rate of 100 and 98.5% (95% confidence interval: 94.3-99.6%), respectively, with one patient undergoing two-stage revision for infection and another undergoing femoral revision for aseptic loosening. Survivorship for aseptic all-cause reoperation at 2- and 5-year follow-up was 93.2% (87.7-96.3%) and 88.2% (80.0-93.2%), respectively. Fourteen patients underwent aseptic reoperation (patellar complications: n = 7 [4.8%]; instability: n = 5 [3.4%]; tuberosity fixation: n = 1 [0.7%]; extensor mechanism failure: n = 1 [1.1%]). Survivorship for all-cause reoperation at 2- and 5-year follow-up were 85% (78.2-90.0%) and 77.7% (68.8-84.3%), respectively. Fifteen patients underwent reoperation for infection (DAIR: n = 14 (9.5%); two-stage revision: n = 1 [0.7%]). Despite some reoperations, this guided-motion hinged-knee TKA system demonstrates excellent survivorship for component revision compared to other modern hinged knee implants reported in the literature. Patients also displayed an improvement in knee ROM at their latest follow-up.