- Two Hole Implants:
- two hole plate, usually a 4.5 mm, is fixed to the superior surface of the symphysis with two
6.5 mm cancellous screws
immediately adjacent to the symphysis pubis;
- screws are inserted on the anterosuperior surface of the pubis on either side of the symphysis and directed to the full depth
of pubis in a posteroinferior direction;
- to provide satisfactory fixation, 6.5-mm cancellous screws with 32-mm threads are used and they should
penetrate full depth of pubis;
- usually, screws of 50-55 mm in length can be accommodated;
- implant appears to loosen to point of accommodating physiologic motion at symphysis pubis, yet adequately resists
tensile stresses across symphysis without loss of reduction;
- fixation failures w/ two hole implants are more common w/ osteoporotic bone;
- ref:
- Two Hole Plate Fixation for Traumatic Symphysis Pubis Diastasis. Webb LX, Gristina AG, Wilson JR, Rhyme AL, Meredith JH, Hansen ST Jr. J Trauma 28: 813-817.
- Four Hole Implants:
- indicated for anterior diastasis w/ or w/o an unstable
posterior injury;
- fixation usually involves a contoured
4.5 mm reconstructive plate applied to the superior surface surface of the pubis;
- usually, fully threaded cancellous screws are used to secure the plate;
- four-hole plate fixation, while maintaining reduction of diastasis, does not allow motion across joint & may be prone
to late problems of loosening or implant fatigue;
- Combined Two and Four Hole Plates:
- the anterior plate may consist of a 3.5 or a 4.5 mm reconstruction plate;
- the plate is usually secured w/ 4.5 mm cortical screws;
- indications are mainly for unstable
posterior injury;
- Box Plate Fixation:
- allows for superior fixation in osteoporotic bone;
- utilizes two 2-hole narrow 4.5 DCP plates placed parallel to each other, one above and one below the the pubic symphysis;
- the inferior plate is recessed w/ in the symphysis;
- the plates are inter-locked utilizing two 6.5 mm screws;
- references:
- Box Plate Fixation of the Symphysis Pubis: Biomechanical Evaluation of a New Technique. J. Orthop Trauma. 1994. Vol 8. No 6. p 483 489.
Comparative radiographic and clinical outcome of two-hole and multi-hole symphyseal plating.
