[Fwd: (StillsNet) Anatomical Reconstruction Of Extramedullary Stem Best In Total Hip Replacement]

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> Anatomical Reconstruction Of Extramedullary Stem Best In Total Hip

> Replacement

> 12/12/2000 11:36:18 AM

> By

>

> Anatomical reconstruction of the extramedullary stem to restore normal hip

> biomechanics has advantages over other stem designs, researchers find.

>

> Stability of the implant and the transfer of stress after total hip

> replacement are affected by the design of the extramedullary stem. Most

> designs result in micromotions in the interfacial region that allow bone

> regrowth.

>

> Investigators conducted a biomechanical study of seven different

> extramedullary stem designs. These were 1) anatomical case reconstruction

> based on computed tomography data; 2) -15 degrees retroverted case; 3) +15

> degrees anteverted case; 4) medial case with femoral neck shortened 10 mm;

> 5) lateral case with femoral neck elongated 10 mm; 6) varus case with CCD

> angle 127 degrees and 7) valgus case with CCD angle 143 degrees.

>

> In all seven variations, the intramedullary shape was anatomically

> reconstructed using computed tomography data.

>

> Results showed that the anatomical reconstruction of the extramedullary stem

> gave the lowest micromotions and the lowest interfacial stresses. The

> anteverted and the lateralized cases gave the worst results.

>

> The investigators conclude that " the present results could be taken as

> biomechanical arguments for the requirement of anatomical reconstruction of

> not only the intramedullary shape but also the extramedullary parameters. "

>

> For more information on Still's Disease please visit the International Still's

Disease Foundation at http://www.stillsdisease.org