[Biodegradable meniscus fixations: a comparative biomechanical study].
OBJECTIVE
Numerous new all inside meniscus repair techniques using biodegradable fixation devices have become available in the last years. Few studies have dealt with the biomechanical properties of these implants so far. The aim of this study was to analyze meniscus repairs under cyclic loading conditions for different fixation devices (Meniscus Arrow, Clearfix Meniscal Screw, Meniscal Dart, BioStinger) and to compare them to standard suture techniques.


METHODS
Eighty meniscus repairs on 27 medial porcine menisci were performed. For biomechanical testing loosening, number of failures, failure modes and failure loads were evaluated under cyclic and maximum loading conditions. Testing was performed on a materials testing machine.


RESULTS
During cyclic loading 10 out of 40 (25%) fixation devices failed. A gap appeared between the 2 parts of the meniscus within the first loading cycles. The failure strengths obtained with the 4 meniscus fixation devices did not differ significantly (Meniscus Arrow: 44 N; Clearfix Meniscal Screw: 35 N; Meniscal Dart: 33 N; BioStinger: 54 N). Besides for the BioStinger, the values of the sutures were significantly higher. The use of a stronger suture material (PDS 0) increased the failure load significantly. During maximum loading the fixation devices failed by both pull-out of the head or the tip of the device, except for the BioStinger showing only pull-out of the head. All sutures failed by breakage, except for the PDS 0 horizontal sutures in which 50% of complete tissue failures could be noted.


CONCLUSIONS
This study shows that meniscal fixation devices may fail under repetitive loading conditions. A gap appeared between the meniscal margins within the first loading cycles irrespective of the suture type and fixation device used. Both gapping and failure modes of the fixation devices may be design-specific. The maximum failure loads differed significantly between the bioabsorbable devices and the sutures. Stronger suture materials increased the failure loads significantly. To allow a complete evaluation of new meniscus fixation devices not only biomechanical, but also biological and clinical parameters need to be analyzed in forthcoming studies.
Seil
R
R
Service de Chirurgie Orthopédique, Cliniques Universitaires de Sarre, 66421 Hombourg, Sarre, Allemagne. rseil@yahoo.com
Rupp
S
S
Jurecka
C
C
Georg
T
T
Kohn
D
D
D020341:Absorbable Implants / Q000592:standards*; D000818:Animals; D001696:Biomechanical Phenomena; D001863:Bone Screws / Q000592:standards*; D004867:Equipment Design; D016268:Internal Fixators / Q000592:standards*; D008422:Materials Testing; D008592:Menisci, Tibial / Q000601:surgery*; D023421:Models, Animal; D009984:Orthopedic Fixation Devices; D013537:Sutures / Q000592:standards*; D013552:Swine; D013718:Tensile Strength; D016474:Weight-Bearing