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Unicompartmental Knee Arthroplasty Revision under Navigation System

March 15, 2015

Contributors: Sang-Min Park, MD; Young-Bong Ko, MD; Kwak Yoon-Ho, MD; Han-Jun Lee, MD; Han-Jun Lee, MD

Introduction: The main technical difficulty encountered during the surgical revision of unicompartmental knee arthroplasty (UKA) by total knee arthroplasty (TKA) is filling bone defects, which are associated with the failed UKA. These parameters can be controlled with computer navigation systems, which have been confirmed for primary TKA, but more rarely for revision TKA. The purpose of this study was (1) to assess the clinical and radiologic outcome of the revision of UKA to TKA under navigation system and (2) to provide a surgical technique based on our experience with navigation-assisted revision of UKA to TKA.

Materials and Methods: From May 2012 to April 2013, the navigation-assisted UKA revision were performed in nine patients (nine knees) who received the same prosthesis under the same navigation system. The clinical results were assessed using the range of motion (ROM), the Hospital for Special Surgery (HSS) score, the Knee Society Knee Score (KSKS), and the Knee Society Functional Score (KSFS). The radiologic results were evaluated using the mechanical femorotibial angle (MAD), coronal and sagittal component angle, and radiolucent line.

Results: The preoperative ROM and the ROM at final follow up was not statistically different (p=0.85). The KSKS and KSFS were significantly improved from the preoperative values (p<0.001). The HSS score was significantly improved at the latest follow up (p<0.001). The pain VAS score was significantly decreased at the latest follow up (p<0.001). The reasons for revision of UKA included three component loosening/failure, three progressive arthritis, three polyethylene wear, and one bearing dislocation. All revised UKAs were same design. At the time of surgery, stemmed implants were used on the tibial side in nine knees (100%) and not on the femoral side. The mean polyethylene liner size used in TKA was 13.3 mm. The MAD was significantly improved from the preoperative value (p=0.03).

Conclusion: With appropriate surgical technique, the navigation assisted revision UKA to TKA technique provides reliable preoperative information, minimal bone cuts, an ideal joint line and limb alignment, less invasive implants, and soft tissue balancing.

Results for "Primary Knee Arthroplasty"

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