PMID- 12721684
OWN - NLM
STAT- MEDLINE
DCOM- 20031002
LR  - 20220317
IS  - 0936-8051 (Print)
IS  - 0936-8051 (Linking)
VI  - 123
IP  - 2-3
DP  - 2003 Apr
TI  - Proximal humeral fractures: how stiff should an implant be? A comparative 
      mechanical study with new implants in human specimens.
PG  - 74-81
AB  - BACKGROUND: The objective of this study was to determine the in vitro 
      characteristics of the clinically used and newly developed implants for the 
      stabilization of proximal humeral fractures under static and cyclic loading. The 
      goal was to optimize implant stiffness for fracture stabilization even in weak 
      bone stock. METHODS: In a laboratory study using 35 fresh human humeri, the 
      specimens were randomized into 5 groups, which included the clinically used 
      humerus T-plate (HTP), the cross-screw osteosynthesis (CSO), the unreamed 
      proximal humerus nail with spiral blade (UHN), the recently developed Synclaw 
      Proximal Humerus Nail (Synclaw PHN) and the angle-stable Locking Compression 
      Plate Proximal Humerus (LCP-PH). The implant stiffness was determined for three 
      clinically relevant load cases: axial compression, torsion and varus bending. In 
      addition, a cyclic varus-bending test was performed to determine the implant 
      properties under cyclic loading. RESULTS: In contrast to a rather elastic and 
      minimally invasive implant(LCP-PH), the conventionally designed ones (Synclaw 
      PHN, CSO, HTP, UHN) showed rather high stiffness values under static loading. In 
      cyclic loading, a strong decrease in stiffness ( p<0.05) was found for the rigid 
      implants HTP and UHN. In comparison with the other implants, only the elastic 
      implant (LCP-PH) showed a significantly lower load reduction in a weak bone stock 
      (17+/-6.2%). CONCLUSION: The high initial stiffness of rigid implants led to an 
      early loosening and failure of the implant-bone interface under cyclic loading. 
      Implants with low stiffness and elastic characteristics, however, appear to 
      minimize the peak stresses at the bone-implant interface, making them 
      particularly suitable for fracture fixation in osteoporotic bone.
FAU - Lill, H
AU  - Lill H
AD  - Department of Trauma and Reconstructive Surgery, University of Leipzig, 
      Liebigstr. 20a, 04103 Leipzig, Germany. lill@medizin.uni-leipzig.de
FAU - Hepp, P
AU  - Hepp P
FAU - Korner, J
AU  - Korner J
FAU - Kassi, J-P
AU  - Kassi JP
FAU - Verheyden, A P
AU  - Verheyden AP
FAU - Josten, C
AU  - Josten C
FAU - Duda, G N
AU  - Duda GN
LA  - eng
PT  - Comparative Study
PT  - Evaluation Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20030212
PL  - Germany
TA  - Arch Orthop Trauma Surg
JT  - Archives of orthopaedic and trauma surgery
JID - 9011043
SB  - IM
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Biomechanical Phenomena
MH  - Bone Plates
MH  - Elasticity
MH  - Female
MH  - *Fracture Fixation, Internal
MH  - Humans
MH  - Male
MH  - Materials Testing
MH  - Middle Aged
MH  - *Prostheses and Implants
MH  - Prosthesis Failure
MH  - Random Allocation
MH  - Shoulder Fractures/*surgery
EDAT- 2003/05/02 05:00
MHDA- 2003/10/03 05:00
CRDT- 2003/05/02 05:00
PHST- 2002/03/05 00:00 [received]
PHST- 2003/05/02 05:00 [pubmed]
PHST- 2003/10/03 05:00 [medline]
PHST- 2003/05/02 05:00 [entrez]
AID - 10.1007/s00402-002-0465-9 [doi]
PST - ppublish
SO  - Arch Orthop Trauma Surg. 2003 Apr;123(2-3):74-81. doi: 10.1007/s00402-002-0465-9. 
      Epub 2003 Feb 12.