Purpose Providing long-term outcome data after rTKA and compare one- versus two-stage and septic versus aseptic revisions. Methods This study represents a single-center retrospective study of first rTKAs performed for any reason with a final follow-up of a minimum of five years. Outcome parameters included stability assessment ROM, radiologic assessment, HSS score, KSS score, OKS score, EQ-5D-3L and VAS. 44 patients were included in the study. Subgroups analysis of one- versus two-stage revision and septic versus aseptic revision was performed. Results The leading causes of rTKA in this mean 11 year follow-up study were aseptic loosening (36%) and periprosthetic joint infection (27%). At the final follow-up, there was a 89% survivorship of the implants. Patients showed a ROM of 114 ± 13°, HSS score of 78 ± 12, KKS objective score of 77 ± 16, KSS expectation and satisfaction score of 32 ± 11, KSS functional activity score of 50 ± 20, OKS of 30 ± 9, VAS of 53 ± 25 and EQ-5D index of 0.649. Functional outcome scores were not significantly altered in the analyzed subgroups. Conclusions In our 11 years follow-up, we obtained 89% implant survivorship. Measurements regarding functional outcome and pain showed results in the medium range of the respective scores, while patient satisfaction lay in the upper third. No significant differences in outcome scores between one- and two-stage revisions and septic versus aseptic revisions were observed. Level of Evidence Level III, retrospective cohort study.

Purpose The purpose of this study is to report and compare outcome data of both primary and revision cases using a rotating hinge knee (RHK) implant. Methods This study retrospectively analyzed 63 cases (19 primary, 44 revisions) at a mean follow-up of 34 ± 8 months after RHK implantation. Outcome parameters were stability, range of motion (ROM), loosening, Hospital of Special Surgery Score (HSS), Knee Society Score (KSS), Oxford Knee Score (OKS), EQ-5D-3L, and Visual Analog Scale (VAS) for overall function. Revision rates and implant survival are reported. Results Eleven percent showed medio-lateral instability < 5 mm, a mean ROM of 115° ± 17° and radiologic loosening occurred in 8% (2% symptomatic). PROMS showed the following results: HSS 79 ± 18, KSS 78 ± 27, OKS 26 ± 10, EQ-5D index 0.741 ± 0.233 and VAS 70 ± 20. Primary cases revealed better outcomes in HHS (p = .035) and OKS (p = 0.047). KSS, EQ-5D index and VAS did not differ between primary and revision cases (p = 0.070; p = 0.377; p = 0.117). Revision rate was 6.3% with an implant survival of 96.8%. Conclusions RHK arthroplasty can be performed with good clinical outcome and low revision rate in revision and complex primary cases. RHK is an option in cases where standard arthroplasty and even implants with a higher degree of constraint have reached their limits. Level of Evidence Level III, retrospective cohort study.