Search Results
Abstract
Background: Ideal suture technique and type in tendon repair are remain unclear. This biomechanical study aimed to assess the biomechanical characteristics of three techniques, modified Kessler (mKE), modified Krackow (mKR), and modified tension Bunnell (mtBU), in sheep Achilles’ tendon tear repair using three suture types, polypropylene, polyester, and ultra-high molecular weight polyethylene (UHMWPE) sutures, which are also compared.
Methods: Sixty-three Achilles’ tendons harvested from sheep were transversely hacked as a replacement for rupture in a standardized measure and repaired using mKE, mKR, and mtBU techniques with No. 2 polypropylene, polyester, and UHMWPE sutures. Biomechanical parameters, such as Young’s modulus, ultimate strength, and strength to the 5-mm gap were recorded for statistical analysis.
Results: The mtBU technique with UHMWPE use resulted in increased ultimate strength, strenght to 5-mm gap, Young’s modulus, and quantity of specimens with low clinical failure modes compared to other techniques with other suture materials. Furthermore, mtBU has the lowest thickness at the repair side of the tendons. This approach showed tendon failure during maximal traction testing, whereas the mKE and mKR had polyethylene and polyester suture failures.
Conclusions: The UHMWPE suture was significantly superior to the other sutures in each suture techniques in terms of strength and durability. The mtBU technique using UHMWPE suture showed better biomechanical results, implying that this repair might be more appropriate to obtain early mobilization after tendon ruptures.
Background:
The use of total first metatarsophalangeal joint (MPJ) arthroplasty to treat patients in which the pain, due to a pathological joint, has not been relieved with a conservative method or for which the disease or disorder is at an advanced stage, is popular. Although meta-analysis of clinical results indicates that this surgical option is efficacious, there are problems with implant failure due to wear of the components. Although there is a plethora of designs of this type of implant in clinical use, there are no literature reports on total first MPJ simulators, which may be used to evaluate, for example, the wear rate of a total first MPJ implant.
Methods:
We designed such a simulator, guided by the biomechanics of the joint. Thus, for example, the implant under test will be articulated at least 40° dorsiflexion, under a 600 N loading, at 1 Hz. Furthermore, the testing stations will be configured to allow testing of any type of first MPJ implant. We also performed a finite element analysis (FEA) study of a model of an articulating station, subjected to a quasi-static load of 1200 N.
Results:
For an articulating station, 1) the highest von Mises stress occurred at the implant-fixture interface; and 2), for the other parts, the minimum factor of safety, against elastic failure, is approximately 9.
Conclusions:
The designed joint simulator is mechanically sound and may be used for wear testing of any type of first MPJ implant. (J Am Podiatr Med Assoc 103(5): 411–417, 2013)
Flake-Austin Modification of the STA-Peg Arthroereisis
A Retrospective Study
The Smith subtalar arthroereisis implant (STA-peg) is used to correct severe collapsing pes valgoplanus in children. Flake and Austin modified the placement of this implant to block the leading wall of the lateral talus. Twenty-one patients with a total of 40 STA-peg procedures were evaluated subjectively and objectively. The average age at the time of surgery was 9.7 years (4 to 16 years). The follow-up period averaged 36 months (12 to 90 months). The subjective, objective, and radiographic results were positive and the complication rate was low. A significant advantage of the Flake-Austin modification of the STA-peg placement in transverse planar dominant foot types is also noted. (J Am Podiatr Med Assoc 91(8): 394-405, 2001)
