Comparison of temporary epiphysiodesis with RigidTacks TM and Blount-Staples in a porcine animal model using MRI

Authors: 
Hillebrand H, Sattelberger J, Gosheger G, Frommer A, Moller-Madsen B, Rahbek O, Gottliebsen M, Abdul-Hussein Abood A, Roedl R, Vogt B
J Orthop Res. 2019 Nov 19. doi: 10.1002/jor.24532.

RigidTackTM is a newly developed implant for total temporary epiphyseodesis. The implant combines the technical advantages of the traditionally used rigid Blount-staples and the newer flexible eight-platesTM. Thus the implant is rigid like the Blount-staples, which may be a biomechanically advantage in temporary epiphyseodesis, and has an easy and guided implantation-technique like the eight-plateTM. As in eight-platesTM , supposedly only two RigidTacksTM are sufficient for temporary epiphyseodesis compared to six Blount-staples in the traditional treatment.

The goal of this study was to compare Blount-staples and RigidTacksTM in regard of the total potential of growth arrest, the occurrence of postoperative implant-associated complications, secondary angular-deformities and central joint-deformations.

Twelve pigs were allocated in two groups (n=6) for treatment of the proximal tibia. Total temporary epiphysiodesis was performed with either four Blount-staples or two RigidTacksTM . MRI-scans were performed before and fourteen weeks after surgery, and the amount and distribution of growth arrest were evaluated by measuring the interphyseal-distance in nine defined zones.

Total temporary epiphysiodesis with two RigidTacks™ resulted in a similar amount of growth arrest as four Blount-staples. No significant coronal or sagittal angular-deformities or joint-deformities were observed in either group; however, one secondary loosening of a Blount-staple occurred.

The study concluded that Blount-staples and RigidTacksTM are adequate implants for total temporary epiphysiodesis. If the precise implant-placement through the guided implantation-technique of RigidTacksTM and a reduced number of implants indeed lead to a reduction of secondary angular-deformities has to be investigated in further clinical trials.