Are Stems Redundant in Times of Metaphyseal Sleeve Fixation?

Background Various options exist for implant fixation in revision total knee arthroplasty. One of it is direct cementless metaphyseal sleeve fixation with stems, which has shown excellent short-term and midterm results. Stemless fixation of sleeves is another fixation option for the treatment of specific bone defects; however, so far no data in larger series exist. The objective of this study was, therefore, to analyze the midterm (3-6.5 years) results of stemless sleeve fixation in a larger revision total knee arthroplasty series. Methods In this prospective study, 85 patients with 109 stemless sleeves have been assessed with a mean follow-up of 58.2 (36-78) months. An exclusion criterion was uncontained type II and type III defects. Analysis included clinical and radiographic assessment. Results The results showed a survival rate of sleeves in 96% of the tibia (27/28) and 100% of the femur (81/81). This results in an overall survival rate of sleeves of 99% (108/109). So far, 10 patients (11.8%) underwent rerevision during the follow-up period. The main reason for failure was infection (4/85; 4.7%). Range of motion, Oxford Knee Score, Knee Society Score, and Functional Score improved significantly. Mechanical leg alignment was within the 3° corridor in all patients. Conclusions In cases with type I and contained type II defects, sleeves without stems are a promising option, with a survival rate of sleeves of 99% after 5 years. Also, the clinical improvement and reconstruction of leg alignment showed excellent results. In uncontained defects and type III defects, however, we do recommend using stems for additional fixation in the diaphysis. Although the midterm results are very promising, long-term data are needed.