[Short-term Effectiveness of Revision Total Knee Arthroplasty with Porous-coated Metaphyseal Sleeve and MBT Implant]

Objective: To evaluate short-term effectiveness of revision total knee arthroplasty (TKA) with porous-coated metaphyseal Sleeve and MBT implant.

Methods: A clinical data of 23 patients (24 knees) who underwent revision TKA by using porous-coated metaphyseal Sleeve combined with MBT implant between March 2015 and April 2017 was retrospectively analyzed. There were 8 males (8 knees) and 15 females (16 knees). The age ranged from 48 to 85 years (mean, 65.4 years). The cause of revision TKA included infection in 14 knees, aseptic loosening in 8 knees, instability in 1 knee, and stiff knee in 1 knee. Bone defects were classified according to the Anderson Orthopaedic Research Institute (AORI) bone defect classification. The femoral defect was rated as type ⅡA in 5 knees, type ⅡB in 17 knees, and type Ⅲ in 2 knees; the tibial defect was rated as type ⅡA in 2 knees, type ⅡB in 20 knees, and type Ⅲ in 2 knees. The mean time between primary TKA and revision TKA was 30.6 months (range, 6-86 months). The preoperative range of motion (ROM) was (56.0±24.9)°. The preoperative Hospital for Special Surgery (HSS) total score was 41.9±14.2; and the pain and function scores were 8.5±5.2 and 33.4±13.5, respectively.

Results: All patients were followed up 12-39 months (mean, 25.6 months). The mean operation time was 2.2 hours (range, 1.6-2.9 hours). The mean intraoperative blood loss was 580 mL (range, 400-1 000 mL). There were 2 knees (8.3%) of intraoperative fracture associated with Sleeve insertion and 1 knee (4.2%) of acute postoperative infection at 25 days after revision TKA. All incisions healed by first intention. No deep venous thrombosis of lower extremity occurred. X-ray film showed that all implants were stable. At last follow-up, slight discomfort after exercise occurred in 4 knees (16.7%); end-of-stem pain in the tibia occurred in 1 knee (4.2%). The ROM was (114.6±5.1)°, which had significant improvement compared with the preoperative result ( =11.698， =0.000). The HSS total score (89.0±10.9), pain score (26.9±6.6), and function score (62.1±5.8) also had significant improvement compared with the preoperative results ( =15.616, =0.000; =12.522, =0.000; =10.076, =0.000).

Conclusion: The porous-coated metaphyseal Sleeve combined with MBT implant in revision TKA has a significant improvement in short-term effectiveness and no signs of implant loosening.