Is augmented femoral lateral plating with helically shaped medial plates biomechanically advantageous over straight medial plates?

Dual plating of comminuted distal femoral fractures allows for early patient mobilization. An additional helically shaped medial plate avoids the medial vital structures of the thigh. The aim of this study is to investigate the biomechanical competence of an augmented lateral locking compression plate distal femur (LCP-DF) using an additional straight versus a helically shaped medial LCP of the same length. Ten pairs of human cadaveric femora were instrumented with a lateral anatomical 15-hole LCP-DF. Following, they were pairwise instrumented with either an additional medial straight 14-hole LCP (group 1) or a 90°-helical shape LCP (group 2). All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading until failure. Initial interfragmentary axial displacement and flexion under static compression were significantly smaller in group 1 (0.11 ± 0.12 mm and 0.21 ± 0.10°) versus group 2 (0.31 ± 0.14 mm and 0.68 ± 0.16°), p ≤ 0.007. Initial varus deformation under static compression remained not significantly different between group 1 (0.57 ± 0.23°) and group 2 (0.75 ± 0.34°), p = 0.085. Flexion movements during dynamic loading were significantly bigger in group 2 (2.51 ± 0.54°) versus group 1 (1.63 ± 1.28°), p = 0.015; however, no significant differences were observed in terms of varus, internal rotation, and axial and shear displacements between the groups, p ≥ 0.204. Cycles to failure and load at failure were higher in group 2 (25,172 ± 6376 and 3017 ± 638 N) compared to group 1 (22,277 ± 4576 and 2728 ± 458 N) with no significant differences between them, p = 0.195. From a biomechanical perspective, helical double plating may be considered a useful alternative to straight double plating, demonstrating ameliorated damping capacities during flexion deformation and safer application as the medial neurovascular structures of the thigh are avoided.

Lateral soft-tissue release through a medial incision: Anatomic comparison of two techniques.

BACKGROUND: The distal soft tissue procedure is an integral part of hallux valgus surgery, providing soft tissue balance and alignment restoration of the first metatarsophalangeal joint. Various approaches have been established to this end. For techniques that do not include a separate dorsal incision, lateral release may be achieved via a transarticular approach or via a medial incision and a dorsal flap over the first metatarsal. Compared to the double-incision technique, these techniques are not only cosmetically superior and thus meet the demands of most surgeons and patients. MATERIAL AND METHODS: Using six pairs of frozen cadaveric feet, lateral release was performed using one of the above techniques in a randomized manner with pair comparison. The specimens were then dissected and the completeness of the release as well as any damage to anatomic structures was documented. RESULTS: The transarticular technique enabled complete release of the metatarsal-sesamoid suspensory ligament (MSL) and the transverse and oblique head of the adductor hallucis muscle in five of six specimens. The comparative technique enabled the same in only two of six cases for the adductor hallucis muscle and in four cases for the MSL. The transarticular approach achieved complete release of the lateral joint capsule in three of six specimens, whereas the dorsal approach achieved no release in any specimen. Neither of the methods caused any macroscopic injury to the surfaces of the first metatarsophalangeal joint. The examined arteries, veins, and nerves remained intact in all specimens treated with the transarticular approach, but dorsal release resulted in one documented injury to the first dorsal metatarsal artery and its concomitant veins. CONCLUSIONS: Compared to release by dissection superficially to the extensor tendons, transarticular release provides a more complete lateral release and less injuries to neurovascular bundles. Further anatomic and clinical studies are needed, however, before conclusive recommendations can be made.