2. Saleh classification of acetabular deficiencies for revision hip arthroplasty

#### 2.1. Introduction

This system of classification was proposed by Saleh et al. in 1999. The study had included 21 expert arthroplasty surgeons and was proposed based on estimation of anticipated bone stock following implant removal [3] (Figure 2).

#### 2.2. Classification

• IIB: Superior with less than one-third superior rim deficient.

• III A: Superior and lateral with 40 to 60% of the host bone intact and partial inherent

• III B: Superior and medial with host bone less than 40% and possibility of occult discontinuity.

Bone grafting techniques depends on the type of acetabular bone defect. Superior dome defect will need structural distal femoral allografts or trabecular metal wedges. Medial wall and ischial defect will need particulate bone grafts. Pelvic discontinuity needs ORIF versus

Gozzard et al. had performed a study to assess the reliability and validity of classification systems used for defects in acetabulum during revision arthroplasty [2]. It was found that there was poor to good intra observer agreement with the consultants (0.24) and moderate to good intra observer agreement with the registrars (0.36). Interobserver agreement was noted to

triflanged custom cage. Unsupportive bone stock will need cup and cage construct.

• IIC: Medial wall defect.

20 Total Hip Replacement - An Overview

mechanical stability.

1.3. Clinical applications

1.4. Reliability

Type III: Defect with non-supportive rim.

Figure 1. Paprosky classification of acetabular deficiencies.

Type I No significant bone loss.

Type II Contained loss of bone stock where there is cavitary enlargement of the acetabular cavity but no wall deficiency.

Type III Uncontained loss of bone stock where there is <50% segmental loss of the acetabulum involving anterior or posterior column.

Type IV Uncontained loss of bone stock where there is >50% segmental loss of the acetabulum affecting both anterior or posterior columns (if there is >50% loss of the acetabulum, involving

Figure 2. Saleh classification. (A) Type uncontained cavitary loss of bone stock. (B) Type III, uncontained (segmental) loss of bone stock involving <50% of acetabulum. (C) Type IV, uncontained (segmental) loss of bone stock involving >50% of the acetabulum.

mostly the medial wall but the columns are intact, then this type of defect is considered type II because of the availability of the columns for reconstruction).

Type V Acetabular defect with uncontained loss of bone stock in association with pelvic discontinuity.

### 2.3. Reliability

Gozzard et al. had observed an Inter-observer reliability testing revealed kappa values of 0.89 for the acetabulum. Average validation value was kappa = 0.86 for the acetabulum [2]. To put things into perspective: clinical epidemiologists consider correlation values of 0.6–0.8 to be "substantial" and between 0.8 and 1.0 to be "perfect association".
