1. Paprosky classification of acetabular deficiencies for revision hip arthroplasty

#### 1.1. Introduction

Wayne Paprosky (Illinois, USA) proposed this classification in 1994 based on his experience with revision of 134 acetabular cups [1] (Figure 1).

#### 1.2. Classification

Type I: Defect with undistorted rim.

Type II: Defect with distorted rim but adequate to support a hemispherical cup.

• IIA: Superior and medial with intact superior rim.

be moderate with consultant and registrars scoring 0.56 and 0.27, respectively. Validity was

Classifications Used in Total Hip Arthroplasty http://dx.doi.org/10.5772/intechopen.77231 21

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

Type II Contained loss of bone stock where there is cavitary enlargement of the acetabular

Type III Uncontained loss of bone stock where there is <50% segmental loss of the acetabulum

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

deemed to be good (κ = 0.65). Overall, the authors found the system to be unreliable.

2. Saleh classification of acetabular deficiencies for revision hip

arthroplasty

2.1. Introduction

2.2. Classification

the acetabulum.

following implant removal [3] (Figure 2).

involving anterior or posterior column.

Type I No significant bone loss.

cavity but no wall deficiency.

Figure 1. Paprosky classification of acetabular deficiencies.


Type III: Defect with non-supportive rim.


#### 1.3. Clinical applications

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

#### 1.4. Reliability

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 be moderate with consultant and registrars scoring 0.56 and 0.27, respectively. Validity was deemed to be good (κ = 0.65). Overall, the authors found the system to be unreliable.
