Metaphyseal Fixation Using Cones and Sleeves for Severe Proximal Tibial Bone Loss

Tibial bone defects are commonly encountered in revision total knee arthroplasty (rTKA) and can be managed with metaphyseal cones or sleeves. Few studies have directly compared tibial cones and sleeves in rTKA, and none have limited this comparison to the most severe tibial defects. The purpose of this study was to evaluate and compare the outcomes of metaphyseal cones and sleeves for tibial reconstruction in rTKA with regards to implant fixation and clinical outcomes.A retrospective review was conducted on patients undergoing rTKA in which metaphyseal cones or sleeves were utilized for addressing metaphyseal bone loss (34 cones and 18 sleeves). Tibial bone loss was classified according to the Anderson Orthopaedic Research Institute (AORI) bone defect classification, with AORI 2B and 3 being included. Patient-reported outcomes and postoperative complications were collected, and a radiographic evaluation of osseointegration or loosening was performed.There were 52 knees included (34 cones, 18 sleeves), with a median follow-up of 41.0 months. All-cause implant survival was 100% at two years and 96% (95% CI [confidence interval]: 76 to 99%) at four years, with 98% of tibial components demonstrating osseointegration at final follow up. During follow-up, there were a total 11 revisions, of which one sleeve was revised secondary to implant loosening. Tibial sleeves had a higher risk of revision compared to tibial cones (P < 0.01), and sleeves fixed with a hybrid technique were more likely to need revision than cones fixed by the same method (P = 0.01).Porous metaphyseal tibial cones and tibial metaphyseal sleeves both performed well at a 41 month median follow-up with no difference in aseptic survivorship between the two constructs. Both demonstrate high rates of osseointegration, low rates of aseptic failure, and significant improvement in Knee Society Scores in patients with severe tibial defects in rTKA.