Comparison of flanged and unflanged acetabular cup design. An experimental study using ceramic and cadaveric acetabuli.
OBJECTIVE
Adequate depth of cement penetration and cement mantle thickness is important for the durability of cemented cups. A flanged cup, as opposed to unflanged, has been suggested to give a more uniform cement mantle and superior cement pressurization, thus improving the depth of cement penetration. This hypothesis was tested experimentally.


METHODS
The same cup design with and without flange (both without cement spacers) was investigated regarding intraacetabular pressure, cement mantle thickness, and depth of cement penetration. With machine control, the cups were inserted into open-pore ceramic acetabular models (10 flanged, 10 unflanged) and into paired cadaver acetabuli (10 flanged, 10 unflanged) with prior pressurization of the cement.


RESULTS
No differences in intraacetabular pressures during cup insertion were found, but unflanged cups tended to migrate more towards the acetabular pole. Flanged cups resulted in thicker cement mantles because of less bottoming out, whereas no differences in cement penetration into the bone were observed.


CONCLUSIONS
Flanged cups do not generate higher cementation pressure or better cement penetration than unflanged cups. A possible advantage of the flange, however, may be to protect the cup from bottoming out, and there is possibly better closure of the periphery around the cup, sealing off the cement-bone interface.
Ørskov
Mette
M
Department of Orthopedics, Lund University and Skåne University Hospital, Lund, Sweden.
Abdulghani
Saba
S
McCarthy
Ian
I
Søballe
Kjeld
K
Flivik
Gunnar
G
D000077:Acetabulum; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001843:Bone Cements; D002102:Cadaver; D002484:Cementation; D002516:Ceramics; D006622:Hip Prosthesis; D006801:Humans; D008954:Models, Biological; D011312:Pressure; D011474:Prosthesis Design; D013314:Stress, Mechanical
D001843:Bone Cements