Background: Total knee arthroplasty (TKA) with a rotating-hinge prosthesis is considered a salvage procedure. While excellent immediate stability is achieved, the historically high failure rate has tempered its use. The goal of this study was to determine clinical outcomes, radiographic results, and survivorship after TKA with contemporary rotating-hinge components. Methods: We identified 408 consecutive TKAs performed with rotating-hinge components for nononcologic indications from 2002 to 2012 at a single academic institution. Two hundred and sixty-four knees (65%) had rotating-hinge TKA components implanted for aseptic etiologies, while 144 knees (35%) were managed with the components in 2-stage reimplantation following infection. Rotating-hinge TKA implants were used for complex primary procedures in 74 knees (18%) and as a revision construct in 334 knees (82%). Clinical outcomes were assessed with the Knee Society scoring system, survivorship analyses, and cumulative incidence of revision. The mean age of the patients at the time of the index arthroplasty was 69 years, and the mean duration of follow-up was 4 years (range, 2 to 12 years). Results: At the most recent follow-up, the mean Knee Society knee score had increased from 51 points preoperatively to 81 points (p < 0.0001), and the mean Knee Society functional score had increased from 26 to 36 points (p < 0.0001). At a mean of 4 years, loosening of components was observed in 13 (3.7%) of 349 knees. At the most recent follow-up, 59 revision procedures and 25 reoperations had been performed. The cumulative incidence of any revision was 9.7% at 2 years and 22.5% at 10 years. The cumulative incidence of revision for aseptic loosening was 1.7% at 2 years and 4.5% at 10 years. Metaphyseal cones were used in 114 knees (28%). Survivorship analysis revealed a trend toward a lower risk of revision (hazard ratio [HR] = 0.69; 95% confidence interval [CI] = 0.39 to 1.22; p = 0.20) and reoperation (HR = 0.51; 95% CI = 0.22 to 1.19; p = 0.12) in patients with metaphyseal cones, despite their use in the most severe of bone defects. Conclusions: Contemporary rotating-hinge TKA implants had a low 10-year cumulative incidence of revision for aseptic loosening of 4.5%. Greater use of metaphyseal fixation has aided this improvement. Patients can expect substantial improvements in clinical outcomes with this revision strategy. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The clinical evaluation of the knee is a fundamental tool to correctly address diagnosis and treatment, and should never be replaced by the findings retrieved by the imaging studies carried on the patient. Every surgeon has his own series of exams with whom he is more confident and on whom he relies on for diagnosis. Usually, three sets of series are used: one for patello-femoral/extensor mechanism pathologies; one for meniscal and chondral (articular) lesions; and one for instability evaluation. This review analyses the most commonly used tests and signs for knee examination, outlining the correct way to perform the test, the correct interpretation of a positive test and the best management for evaluating an injured knee both in the acute and delayed timing.

Tibial tubercle osteotomy (TTO) is indicated to treat patellofemoral (PF) malalignment and chondral disease refractory to conservative treatment. However, there are no systematic reviews describing TTO outcomes in chondral damages without instability. The aims of this study were to (1) assess the quality of the published studies, (2) identify indication for TTO to treat PFP with chondral disease without instability, (3) evaluate the most common TTO techniques, (4) evaluate the clinical outcomes, and (5) evaluate TTO's complication and failure rates. In December 2020, a literature search was performed applying the following criteria: (1) peer-reviewed Level 1-4 studies; (2) English language; (3) human subjects with clinical and/or radiological outcomes; (4) TTO alone or associated with minor cartilage procedure (only drilling, no instability); (5) minimum follow-up 12 months, minimum 10 patients; and (6) no more than 20% of drop-out rate. Data from studies were collected and described with weighted averages and standard deviations. A total of 18 Level 4 studies were included. The average Coleman Methodology Score was 61.5 points (range 48-81). A total of 851 patients (892 knees) were included, with 64.8% of female patients. The weighted average follow-up was 49.1 months (range 12-128.5). Indication for TTOs was poorly described. The main technique used was anteromedialisation (60.4%). In 27.7% of the cases, TTO was associated with lateral release. Different scoring systems were used to evaluate outcomes, with significant improvements. The average rate of good/excellent results was 78.7% (range 57%-100%). Fifteen studies described the complication rate (9.9%), whereas only four reported the failure rate (6.2%). TTOs performed to treat PF malalignment associated with chondral disease without instability provided good clinical outcomes, with acceptable complication/failure rates. However, high-level studies are necessary because of studies' heterogeneity regarding patellofemoral malalignment and chondral disease treatment. Systematic review. Level IV, systematic review of Level IV studies.

Total knee arthroplasty (TKA) is a successful and highly effective procedure in most patients with tricompartmental knee arthritis. Despite the innovations in surgical techniques due to planning software and technological innovations, patients’ dissatisfaction after TKA is still high, at up to 20%. Robotic-assisted surgery (RAS) could be considered as a future option for improving outcomes due to its higher accuracy, precision, and reliability. Robotic systems can be classified as fully active, semi-active, or passive depending on the surgeon’s involvement during the procedure, and as imageless or image-based according to the necessity of radiological exams for the pre-operative planning. Three of the most well-known robotic systems for knee surgery are MAKO^® (Stryker Ltd., Kalamazoo, MI, USA), NAVIO^® (Smith & Nephew, Andover, TX, USA), and ROSA^® (Zimmer Inc., Warsaw, IN, USA). These systems show differences in terms of surgeon involvement, the use of CT scans or X-rays for pre-operative planning, the possibility to perform both unicompartmental knee arthroplasty (UKA) and TKA (or even total hip arthroplasty THA), and in the different kinds of knee prosthesis that can be implanted. This article aims to describe the features of the most used robotic systems for knee arthroplasty, to examine their outcomes and analyze their cost-effectiveness, and to evaluate future perspectives.