Prevalence and risk factors of concomitant malleolar and fibular fractures in patients with distal spiral tibial shaft fractures.

Purpose: (1) To evaluate the incidence and combination types of concomitant malleolar and fibular fractures in patients with distal spiral tibial shaft fractures. (2) To evaluate the risk factors for concomitant malleolar fractures in patients with distal spiral tibial shaft fractures.

Methods: A retrospective review was performed on 64 cases of surgically treated distal spiral tibial shaft fractures with complete radiographs and computed tomography (CT) scans. Data on age, sex, injured side, AO classification of tibial shaft fractures, relative fibular fracture location, patterns and combination types of concomitant malleolar fractures were collected. Univariate analysis was performed to analyse factors associated with concomitant malleolar fractures.

Results: Concomitant fibula fractures were present in 90.6% of the patients; these fractures were predominantly proximal to the tibial fracture, with a significant association between fibular fractures at the same level as the tibia and AO42B fractures (p = 0.0011). Concomitant malleolar fractures occurred in 89.1% of patients, with 39.1% having multiple malleolar fractures. The most common malleolar fracture was the posterior malleolar fracture (PMF), accounting for 70.3% of the cases, which were mostly Bartonicek type 4 fractures (32/45, 71.1%). Anterior inferior tibiofibular ligament (AITFL) avulsion fractures were observed in 39.1% of the cases, which were mostly Rammelt II fractures (10/25, 40%). Lateral malleolar fractures (LMFs) occurred in 29.7% of the cases, which were mostly Weber C fractures (13/19, 68.4%). No significant differences between AO42A and AO42B fractures were found regarding the prevalence of malleolar fractures. Age was associated with the number of concomitant malleolar fracture sites, particularly LMF and AITFL avulsion fractures, whereas sex, fracture side, and fibular fracture site were not significantly associated.

Conclusion: Distal spiral TSFs are strongly associated with malleolar fractures. Concomitant malleolar fractures can be complex, and these patients often exhibit compromised ankle stability. Therefore, a comprehensive evaluation of the ankle joint is important when treating individuals with distal spiral TSFs. A CT scan of the ankle joint is crucial for avoiding misdiagnosis of concomitant malleolar fractures and the potential need for additional fixation of these fractures. Elderly patients are more likely to experience multiple malleolar fractures, and special attention should be given not only to PMFs but also to LMFs and AITFL avulsion fractures.