Biomechanics of the compression hip screw in intertrochanteric fracture

Abstract EN

screw and the modi- ////’٠٠ when fixed changes in the fracture geoin- 'اا/'ااء/'ا»ا/'،ا/ fication of this etry, compression hip screwswere inserted into dry cadav-/٠ fashioned to simulate various types »■/ا)//ا'،/ /'،ا/ر//ء eric loaded to ؛»’١١ intertrochanteric fractures.

Each specimen near physiological load limits of normal walking or to fail-lire and the bone and implant behavior recorded.

Although in all fracture types the DHS could produce compression and impaction at tlie fracture site, only the stable type toi-beyond the physiological limits and with //'،'٠، crated load minimal vertical deflection.

In the unstable fractures, the site was not a linear ’،•ااا/'،اا-ا/ '،ء//(compression produced a one.

The proximal fragment displayed torsion and retro-version displacement relative to tlie distal fragment together various 'راء with compression.

These displacements were degrees depending on tlie type oftlie fracture, til(’ amount of bone contact, the location of bone defect between the two main fragments and the direction ofinclination ofthe fracture plane.

Other factors such as bone quality, accu-racy of reduction and the position of tlie implant in tlie proximal fragment were also important.

The overall loads tolerance were less than the stable type.

Tlie vertical de-marked.

All tlie unstable types showed (Ilf- ’،•ا'،'ااflections ferent failure patterns in tlie form of secondary fracture lines.

The clinical significance oftliis study will he of value ill the modification of preoperative planning, operative tech-Iiiqtte and postoperative rehabilitation program aiming at better clinical results.