Abstract
PURPOSE: Severe bone defects pose a major challenge in total knee arthroplasty (TKA); however, metaphyseal sleeves may be a viable option to treat Anderson Orthopedic Research Institute (AORI) classification Type II bone defects. This study reports the short-term results of metaphyseal sleeves for severe bone defects in the proximal tibia. METHODS: From 2013 to 2019, a total of 10 cases were treated at our hospital with metaphyseal sleeve implants (ATTUNE revision system; DePuy-Synthes MBT, Warsaw, IN, USA), of which 2 cases underwent primary TKA for severe varus deformity, 5 underwent revision, and 3 underwent re-revision. The mean age was 71.2 (57-81) years, and the mean observation period was 5.3 years. RESULTS: There were 5 cases of AORI Type IIa and 5 cases of Type IIb. The mean implant survival time was approximately 4.7 (3.0-6.2) years. There was one case that underwent revision surgery. One patient underwent arthrodesis after implant removal due to infection. The Knee Society score (KSS) was 75 (60-95) points preoperatively and 120 (90-145) points 12-months postoperatively. Excluding 2 cases that underwent revision surgery, no progression of the radiolucent zone, implant migration, or fracture was observed up to the final follow-up of at least 24-months postoperatively. CONCLUSIONS: Metaphyseal sleeves can potentially replace more invasive procedures if the severe defect has little effect on the medial collateral ligament or patellar tendon attachment site with no observable mediolateral instability.