- Discussion:
-see
fracture healing menu and
plate biomechanics menu
- where bone is under compression w/ no gap, dead bone is reabsorbed, & resorption cavities, produced by cutting cones of
osteoclasts,
traverse the fracture plane;
- clinically the ideal result of rigid plating should have primary endosteal healing w/o perceptible periosteal callus;
- degree to which external callus forms is an index of the amount of motion at the fracture site;
-
primary bone healing:
- in direct healing no relevant amount of callus, esp of callus which specifically bridges frx line, becomes visible radiologically;
- radiologic appearance of direct fracture healing is characterized by virtual absence of callus formation;
- when ideal fixation is attained, there is no resorption of bone ends, & fracture heals by revascularization of the bone ends and endosteal callus;
- vascular considerations:
- no more than half of bone circumference is epiperiosteally exposed;
- to minimize further injury to blood supply of bone, the periosteum should be stripped sparringly with a periosteal elevator and only sufficiently
for application of the plate;
- formly orthopedists recommended that the plate be placed on the periosteum rather than the bone;
- report by
Whitesides et. al., however, suggestion that exposure by this technique produces greater blood
supply alteration than an exposure that strips the periosteum with the muscle attached;
- Misc:
- generous lengths of incisions will help to avoid inadvertent stripping during the manipulation;
- as rule plate should not be used to stabilize a fracture of wt bearing bone, but to unload (protect) a fracture stabilized by other means (eg., lag
screws);
- it is important goal of use of plate to at least partially unload fractured bone which has previously been fixed using
screws;
- before plate application, larger comminuted fragments should be secured to main fragments w/ lag
screws to produce interfragmentary compression;
The effects of extraperiosteal and subperiosteal dissection. II. On fracture healing.
The effects of extraperiosteal and subperiosteal dissection. I. On blood flow in muscle.
Comparison of the effects of compression plates and external fixators on early bone-healing.
Effects of plates on cortical bone perfussion. RR Jacobs et al. Journal of Trauma. 1981. Vol 21. p 91-95.
The biomechanics and biology of internal fixation using plates and nails. SM Perren. Orthopaedics. 1989. Vol 12. p 21-34.
Early temporary porosis of bone induced by internal fixation implants. A reaction to necrosis, not to stres protection? SM Perren et al. CORR. Vol 232. 139-151. 1988.
Rigid or sliding plate. A mechanical evaluation of osteotomy fixation in sheep. E Panagiotopoulos MD et al. CORR. No 358. Jan 1999. p 244.
Biomechanical Considerations in Plate Osteosynthesis: The Effect of Plate-to-Bone Compression With and Without Angular Screw Stability.
Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology.
