High incidence of screw penetration in the proximal and distal tibiofibular joints after intramedullary nailing of tibial fractures-A prospective cohort and mapping study.

Background: Intramedullary-nails (IMN) are the treatment of choice for most tibial shaft fractures due to their minimally-invasive nature and non-demanding surgical technique. However, a potential iatrogenic pitfall is intra-articular interlocking screw positioning within the proximal (PTFJ) and distal (DTFJ) tibiofibular joints that may go unrecognized.

Objective: To evaluate the incidence of intra-articular screw penetration of the PTFJ and DTFJs after interlocking of IMN for tibial fractures.

Intervention: Reamed IMN using modern techniques, including proximal interlocking via standard aiming jig and distal interlocking either freehand or using SureShot.

Methods: Prospective series of 165 consecutive patients with a tibial shaft fracture managed with an IMN. Diagnosis and incidence of penetration of the PTFJ and DTFJ was assessed on protocolled low-dose postoperative CT-scans (standardized clinical practice for assessing rotational alignment). The degree of penetration of the TFJ's was graded as: Grade 1-slight breach of the tibial cortex; Grade 2-clear penetration of the tibial cortex with intra-articular screw tip; and Grade 3-penetration of both tibial- and fibular cortices with screw tip in fibula.

Results: Of the 165 tibial shaft fractures, using the AO/OTA classification, 69% were simple, 16% wedge and 15% complex fractures. Following IMN 42% of patients had intra-articular screw penetration of their PTFJ whilst 39% had penetration of their DTFJ. 66% of patients had penetration of either one- or both of their TFJs. The grading of PTFJ violation was distributed as follows: Grade 1 in 24 patients; Grade 2 in 26 patients and Grade 3 in 19 patients. DTFJ violation was graded as: Grade 1 in 21 patients; 40 patients had Grade 2 violation; and four patients had a Grade 3 penetration.

Conclusions: This diagnostic imaging study reports a high rate of intra-articular screw penetration of the PTFJ and DTFJ after interlocking of IMN for tibia shaft fractures. A prospective cohort study is underway to evaluate its clinical significance. Changes to enable alteration in forced angle of interlocking screw trajectory and avoidance of the anteromedial to posterolateral locking screw may reduce the incidence of TJF violation.

Level Of Evidence: Level II - Diagnostic Imaging Study.