5. AAOS classification of femoral bone deficiencies for revision hip arthroplasty

#### 5.1. Introduction

This classification was first proposed by D'Antonio et al. (Pennsylvania, USA) in 1989 and later adopted by American Academy of Orthopedic Surgeons (AAOS) [6] (Figure 4).

#### 5.2. Classification

Type I: Segmental deficiencies.

1a: Proximal either partial or complete.

1b: Intercalary.

1c: Greater trochanteric.

Type II: Cavitary deficiencies (cancellous, cortical or ectasia).

Type III: Combined.

Type IV: Rotational or angular malalignment.

Type V: Femoral stenosis.

Type VI: Femoral discontinuity.

Figure 4. AAOS classification.

#### 5.3. Clinical applications

This classification is very useful in describing the bone defect accurately but has less role in guiding the surgeon determine the reconstructive option.

#### 5.4. Reliability

Type 4: Impaction bone grafting with tapered cemented stem if intact cortex. Composite

This classification was first proposed by D'Antonio et al. (Pennsylvania, USA) in 1989 and later

prosthesis allograft if no proximal cortex. Long cemented stem is an option in elderly.

5. AAOS classification of femoral bone deficiencies for revision hip

adopted by American Academy of Orthopedic Surgeons (AAOS) [6] (Figure 4).

arthroplasty

24 Total Hip Replacement - An Overview

5.1. Introduction

5.2. Classification

1b: Intercalary.

Type III: Combined.

Type V: Femoral stenosis.

Figure 4. AAOS classification.

Type VI: Femoral discontinuity.

Type I: Segmental deficiencies.

1c: Greater trochanteric.

1a: Proximal either partial or complete.

Type IV: Rotational or angular malalignment.

Type II: Cavitary deficiencies (cancellous, cortical or ectasia).

Gozzard et al. in their study observed the inter observer agreement among consultants and registrars. They noted a fair agreement (k value of 0.28) among consultants and a poor agreement (k value of 1.0) among the registrars.
