Temporizing cast immobilization is a safe alternative to external fixation in ankle fracture-dislocation while posterior malleolar fragment size predicts loss of reduction: a case control study

Abstract

Background To determine if temporizing cast immobilization is a safe alternative to external fixator (ex-fix) in ankle fracture-dislocations with delayed surgery or moderate soft-tissue injury, we analysed the early complications and re-dislocation rates of cast immobilization in relation to ex-fix in patients sustaining these injuries. Methods All skeletally mature patients with a closed ankle fracture-dislocation and a minimum 6-months follow-up treated between 2007 and 2017 were included. Baseline demographics, comorbidities, injury description, treatment history and complications were assessed. Results In 160 patients (94 female; mean age 50 years) with 162 ankle fracture-dislocations, 35 underwent primary ex-fix and 127 temporizing cast immobilizations. Loss of reduction (LOR) was observed in 25 cases (19.7%) and 19 (15.0%) were converted to ex-fix. The rate of surgical site infections (ex-fix: 11.1% vs cast: 4.6%) and skin necrosis (ex-fix: 7.4% vs cast: 6.5%) did not differ significantly between groups (p = 0.122 and p = 0.825). Temporizing cast immobilization led to an on average 2.7 days earlier definite surgery and 5.0 days shorter hospitalization when compared to ex-fix (p < 0.001). Posterior malleolus fragment (PMF) size predicted LOR with ≥ 22.5% being the threshold for critical PMF-size (p < 0.001). Conclusion Temporizing cast immobilization was a safe option for those ankle fracture-dislocations in which immediate definite treatment was not possible. Those temporized in a cast underwent definite fixation earlier than those with a fix-ex and had a complication rate no worse than the ex-fix patients. PMF-size was an important predictor for LOR. Primary ex-fix seems appropriate for those with ≥ 22.5% PMF-size. Trial registration The study does not meet the criteria of a prospective, clinical trial. There was no registration.

Primary Screw Fixation of the Medial Malleolus in Highly Unstable Ankle Fracture-dislocations as an Alternative to Temporary Ankle-spanning External Fixation

“…11,18,19 Interposition of soft tissues such as the tibialis posterior tendon may make closed reduction impossible and predispose for persistent fracture-dislocation. 6,11,18,[20][21][22] The intrinsic stability of the ankle joint depends on the integrity of the medial and lateral malleolus together with the medial and lateral ligaments and the syndesmotic complex. The deep deltoid ligament and the posterior colliculus of the medial malleolus are the primary stabilizers of the ankle and provide important restraint to talar external rotation.…”

“…Besides a pre-existing joint deformity or plantarflexion of the foot, associated conditions of the injury, such as a ruptured deltoid ligament or a fractured medial malleolus, the occurrence of a Volkmann fracture and the size of this fragment have been recognized to increase instability. 11,18,19 Interposition of soft tissues such as the tibialis posterior tendon may make closed reduction impossible and predispose for persistent fracture-dislocation. 6,11,18,[20][21][22] The intrinsic stability of the ankle joint depends on the integrity of the medial and lateral malleolus together with the medial and lateral ligaments and the syndesmotic complex.…”

“…Several factors have been identified to increase instability with recurrent loss of reduction of fracture-dislocations of the ankle. Besides a pre-existing joint deformity or plantarflexion of the foot, associated conditions of the injury, such as a ruptured deltoid ligament or a fractured medial malleolus, the occurrence of a Volkmann fracture and the size of this fragment have been recognized to increase instability 11,18,19 . Interposition of soft tissues such as the tibialis posterior tendon may make closed reduction impossible and predispose for persistent fracture-dislocation 6,11,18,20–22 …”

“…1). [11][12][13] Recurrent fracture-dislocation, in particular when remained unnoticed in a plaster or splint, may lead to devastating soft tissue and skin problems. 11,13,14 Furthermore, secondary loss of reduction may also occur associated with discomfort and pain when the splint is repeatedly removed to assess the soft tissues before definitive ORIF can be performed.…”

“…[11][12][13] Recurrent fracture-dislocation, in particular when remained unnoticed in a plaster or splint, may lead to devastating soft tissue and skin problems. 11,13,14 Furthermore, secondary loss of reduction may also occur associated with discomfort and pain when the splint is repeatedly removed to assess the soft tissues before definitive ORIF can be performed. 15 Ankle-spanning external fixation is an established treatment modality for highly unstable ankle fracture-dislocations with critical soft tissues and/or when immediate ORIF is not feasible.…”