[Bone defects in revision total knee arthroplasty: classification and management]

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Reconstructive Surgery

Background:

• Revision total knee arthroplasty (TKA) requires bone defect reconstruction for implant stability and joint line restoration.
• Existing classifications, such as Stockley et al. (1992) and Engh and Parks (1994), guide treatment strategies for bone defects.
• Aseptic loosening is a common indication for revision TKA, necessitating effective bone defect management.

Purpose of the Study:

• To present a classification system for bone defects encountered during revision total knee arthroplasty.
• To correlate bone defect classification with appropriate reconstructive techniques.
• To review the clinical consequences of different bone defect types and their management.

Main Methods:

• Review of bone defect classifications for revision total knee arthroplasty (TKA).
• Analysis of reconstructive options including structural allografts, metal wedges, cancellous allograft, modular revision components, bulk allografts, and modular tumor endoprostheses.
• Clinical experience from over 150 revision TKA procedures at the authors' institution.

Main Results:

• Bone defects in revision TKA are categorized as contained or uncontained (Stockley et al.).
• Engh and Parks classification aids reconstruction for aseptic loosening, with specific recommendations for Grade 1, 2, and 3 defects.
• Reconstruction options vary from allografts and modular components for lower-grade defects to bulk allografts or tumor endoprostheses for higher-grade defects.

Conclusions:

• A clear classification of bone defects is essential for successful revision total knee arthroplasty.
• Tailoring reconstruction methods to defect type ensures implant stability and joint line congruity.
• This review synthesizes existing classifications and clinical outcomes to guide surgical decision-making in revision TKA.