Review Article: Bone Defect Classifications in Revision Total Knee Arthroplasty

Abstract

There are several classification systems for bone defects in revision total knee arthroplasty. Each has its own drawbacks, and none satisfies all the clinical demands. Therefore, a new classification system and treatment guideline based on a combination of criteria (location, side, containment, and severity of the bone defect) is necessary.

Influence of varying stem and metaphyseal sleeve size on the primary stability of cementless revision tibial trays used to reconstruct AORI IIA defects. A simulation study

“…The CT scan of the implanted tibia showed an AORI type IIA defect, as classified by the operating surgeon. At surgery, after removal of the tibial component, the proximal tibia had a posterolateral cavitatory (contained) defect measuring approximately 8 cm 3 (2 cm in each axis).…”

Bone Defects in Revision Total Knee Arthroplasty and Management

“…Anderson Orthopaedic Research Institute classification of bone defects: (A) type I (intact metaphyseal bone with minor defects not compromising the stability of a revision component), (B) type IIA (damaged metaphyseal bone with defects in one femoral condyle or tibial plateau), (C) type IIB (more than one damaged metaphyseal bone), and (D) type III (deficient metaphyseal bone with bone loss compromising a major portion of the condyle or plateau). The latter defects are occasionally associated with collateral or patellar ligament detachment and usually require bone grafting or custom implants.…”

“…There are various classification systems of bone defects that are mainly based on size, severity, and location of the defects that enable accurate preoperative planning for management, predict outcomes, as well as provide guidelines on treatment and rehabilitation 15,16 . Among these classifications, the Anderson Orthopedic Research Institute (AORI) classification is the most practical and frequently used system which predominantly depends on the size of the bone defect originated from the tibia and femur 17 . According to the AORI classification, bone defects are classified into three types for tibia (T1, T2, T3) and femur (F1, F2, F3) separately 18 .…”

“…In type 3 (T3 and F3) defects, there is significant cancellous metaphyseal bone loss compromising the ligamentous instability of a majorportion of the condyle or plateau (Table 1) ( Fig. 2) 15,17 .…”

“…The Anderson Orthopedic Research Institute classification of bone defects in revision of total knee arthroplasty[15][16][17] Type Severity of bone defects in tibia (T) and femur(without compromising the stability of a revision component, normal development of the posterior condyles Type 2A (T2A and F2A) Metaphyseal bone damage and cancellous bone loss in one femoral condyle/tibial plateau, reduced development of the posterior condyles, requiring reconstruction to maintain implant stability Type 2B (T2B and F2B) Metaphyseal bone damage and cancellous bone loss in one or both femoral condyle/tibial plateau, reduced development of the posterior condyles, requiring reconstruction to maintain implant stability Type 3 (T3 and F3) Significant cancellous metaphyseal bone loss compromising the ligamentous instability of a major portion of the tibial or femoral condyle, association with patellar tendon detachment Anderson Orthopaedic Research Institute classification of bone defects: (A) type I (intact metaphyseal bone with minor defects not compromising the stability of a revision component), (B) type IIA (damaged metaphyseal bone with defects in one femoral condyle or tibial plateau), (C) type IIB (more than one damaged metaphyseal bone), and (D) type III (deficient metaphyseal bone with bone loss compromising a major portion of the condyle or plateau). The latter defects are occasionally associated with collateral or patellar ligament detachment and usually require bone grafting or custom implants 17 .…”