Effect of Posterior Malleolar Fixation on Syndesmotic Stability

Abstract

Background: Transsyndesmotic fixation with suture buttons (SBs), posterior malleolar fixation with screws, and anterior inferior tibiofibular ligament (AITFL) augmentation using suture tape (ST) have all been suggested as potential treatments in the setting of a posterior malleolar fracture (PMF). However, there is no consensus on the optimal treatment for PMFs. Purpose: To determine which combination of (1) transsyndesmotic SBs, (2) posterior malleolar screws, and (3) AITFL augmentation using ST best restored native tibiofibular and ankle joint kinematics after 25% and 50% PMF. Study Design: Controlled laboratory study. Methods: Twenty cadaveric lower-leg specimens were divided into 2 groups (25% or 50% PMF) and underwent biomechanical testing using a 6 degrees of freedom robotic arm in 7 states: intact, syndesmosis injury with PMF, transsyndesmotic SBs, transsyndesmotic SBs + AITFL augmentation, transsyndesmotic SBs + AITFL augmentation + posterior malleolar screws, posterior malleolar screws + AITFL augmentation, and posterior malleolar screws. Four biomechanical tests were performed at neutral and 30° of plantarflexion: external rotation, internal rotation, posterior drawer, and lateral drawer. The position of the tibia, fibula, and talus were recorded using a 5-camera motion capture system. Results: With external rotation, posterior malleolar screws with AITFL augmentation resulted in best stability of the fibula and ankle joint. With internal rotation, all repairs that included posterior malleolar screws stabilized the fibula and ankle joint. Posterior and lateral drawer resulted in only small differences between the intact and injured states. No differences were found in the efficacy of treatments between 25% and 50% PMFs. Conclusion: Posterior malleolar screws resulted in higher syndesmotic stability when compared with transsyndesmotic SBs. AITFL augmentation provided additional external rotational stability when combined with posterior malleolar screws. Transsyndesmotic SBs did not provide any additional stability and tended to translate the fibula medially. Clinical Relevance: Posterior malleolar fixation with AITFL augmentation using ST may be the preferred surgical method when treating patients with acute ankle injury involving an unstable syndesmosis and a PMF ≥25%.

Chronic lateral ankle instability using anterior tibiofibular ligament distal fascicle transfer augmentation repair: an anatomical, biomechanical, and histological study

“…To match the repeated measures experimental design ( Stake et al, 2023 ), random-intercept linear mixed-effects models were used to compare the displacement during the anterior drawer test at neutral and at 30° of plantar flexion, the Cotton test, and the axial load test at different positions (30° plantar flexion, 20° dorsiflexion, 15° inversion, 10° eversion, 5° internal rotation, and 5° external rotation). The restricted maximum likelihood method was performed to estimate the model.…”

Das hintere Kantenfragment

“…Das Vorliegen einer trimalleolaren Fraktur und ein damit einhergehendes hinteres Kantenfragment ist ein prognostisch ungünstiger Faktor bei Sprunggelenkfrakturen [2,7,9,24,25,38,30,39,40]. Bereits 1977 wurde erstmalig ein schlechteres funktionelles Outcome bei Vorliegen eines hinteren Kantenfragmentes in Form einer vermehrten posttraumatischen Arthrose des Sprunggelenkes festgestellt [41].…”

“…Langzeitergebnisse präsentierten eine verbesserte Funktion des Sprunggelenkes nach osteosynthetischer Versorgung des hinteren Kantenfragmentes im Vergleich zu konservativen Therapien. Dabei sorgt eine osteosynthetische Versorgung mittels direkter Plattenosteosynthese im Gegensatz zur (in-)direkten Schraubenosteosynthese für eine bessere Stabilität des Sprunggelenkes, was gleichzeitig zu einer Minderung notwendiger additiver Stabilisierungsverfahren der Syndesmose führte [9,10,34,38,39,40]. Trotz Kenntnisnahme der oben aufgeführten Risikofaktoren und verbesserter Therapiestrastellt die Behandlung eines hinteren Kantenfragmentes im Rahmen einer komplexen Sprunggelenkverletzung weiterhin eine Herausforderung in der klinischen und operativen Behandlung dieser Patienten dar.…”

“…5).Dieses Dokument wurde zum persönlichen Gebrauch heruntergeladen. Vervielfältigung nur mit Zustimmung des Verlages 10,34,38,39,40]…”