The risk of violating the posterior malleolar fracture when nailing the ipsilateral concomitant spiral distal tibial fracture

Abstract

BackgroundFor a distal tibial spiral fracture combined with a non-displaced posterior malleolar fragment (PMF), we proposed a hypothesis that the treating surgeon could assess the size of the PMF to determine the need for stabilizing that structure first before rodding the tibia.Materials and methodsFifty 3-D models (22 females) of combined distal tibial and posterior malleolar fractures from one trauma center were reconstructed. In each case, a virtual tibial intramedullary nail (vIM nail) with three distal anteroposterior (AP) locking screws (S13, S15 and S37, the number indicating the distance from the screw to the nail tip) were inserted into the center of the tibial canal and ended on top of the distal tibial physeal scar. Contact between the screws and the PMF was defined as causing PMF displacement. The relationship between PMF secondary displacement and traumatic anatomic factors (the fragment area and height of the PMF) was explored. Then, the parameters were justified by analyzing intraoperative radiographs of 35 cases treated by nail with single locking screw (S15) design.ResultsIn the analog experiment, multiple logistic regression analysis revealed that the height of the PMF could confidently predict the risk of fragment displacement (S13: odds ratio [OR] 1.18, 95% confidence interval [CI] 1.06–1.32; S15: OR 1.15, 95% CI 1.05–1.27). Regarding the height of the PMF, the receiver operating characteristic established a cut-off value of 31.2 mm for preliminary fixation of the fragment with 88.89% sensitivity and 88.89% specificity. In the operation group the nail stopped on the top of distal tibial physeal scar, no PMF secondary displacement occurred when the PMF height was less than 31.2 mm. However, the incidence of secondary displacement was 93.33% when the height of the PMF exceeded 31.2 mm.ConclusionWhen the distal tibial physeal scare was set as the limit of nail insertion depth, the height of the PMF could be used as a reliable reference predicting the risk of PMF secondary displacement caused by distal anteroposterior locking screw.

Classifications of posterior malleolar fractures: a systematic literature review

“…Zhang et al . were able to show that the potency of the Bartoníček/Rammelt classification also applies to distal tibial spiral fractures with associated PMF [ 82 ]. One objection is the imprecise definition of type 5 fractures, which includes all fractures that cannot be classified as type 1–4.…”

Incidence and missed diagnosis risk of occult posterior malleolar fractures associated with the tibial shaft fractures: a systematic review

“…However, other scholars believe that a surgical intervention is only needed for PMFs with displacement of fracture fragments ≥ 2 mm and instability or the proportion of fracture lines involving ≥ 25–30% of the articular surface [ 33 , 34 , 44 – 46 ]. When the fragments of PMFs were not displaced and small enough and if the intramedullary nail was properly inserted, the necessity of additional surgical fixation of the fragment could be eliminated [ 23 , 40 ]. Of note, in a prospective study, Hou et al [ 2 ] stated that spiral TSFs are commonly associated with PMFs, classified such combined injuries into four types, and recommended corresponding treatment strategies according to the different types of posterior malleolar injuries and the different radiologic examinations, which has a certain scientific basis.…”

Far Proximal and Far Distal Tibial Fractures: Management with Intramedullary Nails

“…At times, more than one fracture line is seen. For preoperative planning, we routinely request a CT scan with 3-D reconstructions [25,26] (Figure 8). This is a valuable tool that allows to depict which might be the location and trajectory of percutaneous screws that maintain the epiphyseal bone block as a whole unit, before insertion of the nail.…”

“…Percutaneous fixation with either 3.5 or 2.7 mm screws prevents articular displacement during final impaction of the nail. At times, the coronal fracture is a split fracture of a large posterior articular fragment in discontinuity with the diaphysis [25,28]. In these cases, limited open reduction and fixation with a T-shaped 3.5 mm plate are performed, which can be positioned anteriorly or posteriorly prior to nail insertion (Figure 9a-d).…”