Duke Orthopaedics
Wheeless' Textbook of Orthopaedics

THR: Press Fit Acetabular Component

- See: Total Hip Replacement Menu:
           - acetabular component revision:
           - operative considerations for hip dyplasia
           - protrusio
           - reaming technique:
           - component insertion:
           - component position:
           - screw placement:
           - bone grafting for acetabular defects:
           - acetabular component revision:

- Discussion:
    - design of acetabular components: (see surface coating)
    - acetabular component loosening:
    - osteolysis
    - normal bone ingrowth:
            - generally for bone ingrowth to occur, component must lie within 40-50 micrometers of the acetabulum, and have enough mechanical stability (less than 40 to
                  50 micrometers) inorder for host bone ingrowht to occur;
            - Bloebaum RD, et al (1997), bone ingrowth into component averages only 12%, even though 84% of cup surface was in contact w/ periprosthetic bone;
                  - bone ingrowth was found to be uniform in all zones, most likely due to the uniform distribution of stresses from the metal backing; 
            - references:
                  - Postmortem analysis of consecutively retrieved asymmetric porous-coated tibial components.
                  - Histological and radiographic assessment of well functioning porous-coated acetabular components. A human postmortem retrieval study.   
                  - Incomplete seating of press-fit porous-coated acetabular components: the fate of zone 2 lucencies.

    - acetabular offset and latealized acetabular liner:
            - this may induce additional torque and shear at the metal osseous surface leading to loosening;
            - references:
                  - Offset acetabular components introduce torsion on the implant and may increase the risk of fixation failure.
                  - Histological and radiographic assessment of well functioning porous-coated acetabular components. A human postmortem retrieval study.
                  - Acetabular Revision With a 7-mm Lateral Offset Component Inserted Without Cement in Patients Who Have Acetabular Deficiency.
                  - Midterm Radiographic Comparison of Cementless Acetabular Shells Containing Lateralized and Nonlateralized Liners. 
    - types of press fit surfaces: 
    - acetabular liner / femoral head size: (vs metal on metal)
           - as pointed out by Jasty M, et al (1997), the thickness of the polyethylene component is especially important in metal backed press fit components;
                  - w/ smaller acetabular components consider using a 26 mm rather than a 28 mm head in order to better prevent osteolysis;
           - as noted by Cobb, et al (1997), there was no indication of early loosening of elevated rim liners at 5 years as compared to neutral liners;
           - optimally orthopaedists should be able to choose specific liners based on long term data of liner survival;
                  - Hylamer liner from DePuy is associated w/ early signs of wear and osteolytic changes.
           - references: 
                  - Wear of polyethylene acetabular components in total hip arthroplasty. An analysis of one hundred and twenty-eight components retrieved at autopsy or revision operations.
                  - Effect of femoral head size on wear of the polyethylene acetabular component.
                  - Size of the femoral head and acetabular revision in total hip-replacement arthroplasty.
                  - Effect of the elevated-rim acetabular liner on loosening after total hip arthroplasty. 
                  - Elevated-rim acetabular components. Effect on range of motion and stability in total hip arthroplasty.
                  - Complications of total hip arthroplasty associated with the use of an acetabular component with a Hylamer liner. 
                  - Impingement and loosening of the long posterior wall acetabular component.   
                  - Effect of femoral head size and abductors on dislocation after revision THA.
                  - Range of motion and stability in total hip arthroplasty with 28-, 32-, 38-, and 44-mm femoral head sizes

    - outcomes:
         - as noted by Bohm and Bosche (1998), the 11 year survivorship of press fit Harris Galante components was 97.7%;
                - there was only one case of osteolysis in this study;
                - mean postoperative inclination was 42 deg;
                - holes in the acetabular component did not correlate with pelvic osteolysis;
    - references: 
         - Survival analysis of the Harris-Galante I acetabular cup.
         - Acetabular augmentation in primary and revision total hip arthroplasty with cementless prostheses.
         - Comparison of porous-threaded and smooth-threaded acetabular components of identical design. Two- to four-year results.
         - Comparison of in vivo cementless acetabular fixation.
         - A preliminary report of the use of a cementless acetabular component with a cemented femoral component.
         - Metal-backed acetabular cups in total hip arthroplasty.
         - Further follow-up on socket fixation using a metal-backed acetabular component for total hip replacement. A minimum ten-year follow-up study.
         - Range of motion caused by design of the total hip prosthesis.
         - Hip Replacement with a Threaded Acetabular Cup. A Follow-up Study.
         - Total hip replacement with insertion of an acetabular component without cement and a femoral component with cement. Four to seven-year results.
         - Early failure of acetabular components inserted without cement after previous pelvic irradiation.
         - Cementless press-fit cup. Principles, experimental data, and three-year follow-up study.
         - Development and first experience with an uncemented press-fit cup.
         - Postmortem Analysis of Bone Ingrowth into Porous Coated Acetabular Components.   
         - Histological and radiographic assessment of well functioning porous-coated acetabular components. A human postmortem retrieval study. 
         - Fixation of acetabular cups without cement in total hip arthroplasty. A comparison of three different implant surfaces at a minimum duration of follow-up of five years. 
         - Fixation of the acetabular component: the case for cementless bone ingrowth modular sockets

- Radiographic Evaluation:
    - preop acetabular x-ray evaluation:
           - protrusio:
                  - reference:
                         - Radiographic measurements in protrusio acetabuli.
           - bone grafting for acetabular defects:
           - references:
                  - The acetabular teardrop and its relevance to acetabular migration.
                  - Bone grafting in total hip replacement for acetabular protrusion.
    - postop radiographic evaluation:
           - acetabular component loosening:
           - component position;
           - polyethylene wear:
           - osteolysis:
                  - references:
                         - Severe Osteolysis of the Pelvis in Association with Acetabular Replacement without Cement.
                         - The relationship between design, position, and articular wear of acetabular components inserted without cement and development of pelvic osteolysis
                           - Are cementless acetabular components the cause of excess wear and osteolysis in total hip arthroplasty?

- Complications:
    - acetabular fracture:
           - acetabuli should not be underreamed by more than 1 mm, especially in osteoporotic bone;
           - underreaming of the acetabulum by two milimeters may result in frx in 20-25% of cases;
           - when intra-operative fracture is recognized intra-operatively, then augment the component with as many acetabular screws as possible;
    - acetabular component loosening:
    - dislocation
    - screw insertion injuries;
    - osteolysis
    - protrusio:
    - references:
           - Periprosthetic fractures of the acetabulum during and following total hip arthroplasty.   
           - Fracture of the acetabulum during insertion of an oversized hemispherical component.
           - The elevated-rim acetabular liner in total hip arthroplasty: relationship to postoperative dislocation.

Secondary total hip replacement after fractures of the femoral neck.

Current status of acetabular fixation in primary total hip arthroplasty.

Failure of the Mecring screw-ring acetabular component in total hip arthroplasty. A three to seven-year follow-up study.

The definition and measurement of acetabular orientation.

Cementless Acetabular Fixation at Fifteen Years. A Comparison with the Same Surgeon's Results Following Acetabular Fixation with Cement.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Sunday, October 13, 2013 11:01 am

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