The Incidence Of Fracture And Displacement Of Sustentaculum Tali In Intra-articular Calcaneal Fractures And Its Effect On The Surgical Reduction

Objective: The calcaneus is the most commonly clinical fractured tarsal bone. Calcaneal fractures accounting for about 75% for intra-articular fractures. The patients sustaining calcaneal fractures are mainly in young men aged 36 to 40 years, the mechanism of injury is typically high-energy axial loading of the calcaneal, usually fall from height. Because of its anatomical structure and surrounding soft tissue are different from other bones,the treatment is more complex and special than other fractures. The treatment cost is expensive and the treatment period is long, and some patients can be highly disabling. Displaced intra-articular calcaneal fractures likely result in traumatic arthritis, ankle joint motion limitation, foot pain and deformity. This fracture has a great socioeconomic impact, so it is called "poverty fracture". Conservative treatment can not completely reset the fracture and can not be effectively fixed, easily lead to deformity healing. In recent years, with the rapid development of calcaneal fracture mechanism and internal fixation technology, the operation becomes the first choice for the treatment of displaced intra-articular calcaneal fractures.Orthopedics physicians in the surgical treatment of displaced calcaneal fractures, how to choose the incision has not yet reached a consensus. Surgical treatment of displaced calcaneal fractures typically occur through a lateral approach. In addition, they also believe that the sustentacular fragment in displaced intra-articular calcaneal fractures has historically been portrayed as a ‘‘constant fragment’’, bound to the talus by the interosseous and deltoid ligament complex and arounding tendons. The purpose of this study was to characterize the frequency, magnitude, and mode of displacement of the sustentaculum tali, and then to investigate whether the ‘‘constant fragment’’ can maintain the anatomical alignment and its effect on the reduction of the fracture during operation.Methods: Computed tomographic(CT) scans of 311 patients with intra-articular calcaneal fractures admitted to The Third Hospital of Hebei Medical University between October 2013 and August 2015 were retrospectively reviewed, including outpatient and inpatient. All the data was extracted from the hospital registration system, calcaneal fractures were graded according to the Sanders classification. Demographics and mechanisms of injury, magnitude, sustentacular fracture patterns, and mode of displacement of the sustentaculum tali were recorded, and associated foot injuries were also noted.Angulation and translation of the sustentacular fragment as well as gapping and intra-articular fractures of the middle facet were examined. Angulation exceeding 10° and translation of more than 3 mm were considered diagnostic of displacement.Results: over the study period, 311 patients with 347 calcaneal fractures met the inclusion criteria. These patients had a mean age of 41.77±0.68 years. A sustentaculum tali fracture was present in 201(57.9%)of the patients. The most common Sanders type was II(42.8%), followed by III(34.3%), IV(19.9%), and I(3%).One hundred and fifty-four(76.6%) of the sustentacular fractures were coronal fracture lines,twenty-six(12.9%)were Sagittal fracture lines,thirteen(6.5%)were comminuted,four(2%)were "T" shaped or inverted "T" shaped fracture lines,and two(1%)were horizontal fracture lines. Of the 201 fractures, thirty-seven(18.4%) had angulation of the sustentacular fragment of >10°, twenty-two(10.9%)had translation of >3 mm.Conclusion: The incidence(57.9%)of fracture of sustentaculum tali in intra-articular calcaneal fractures is very high. Sustentaculum tali is not truly constant, The possibility of translation and angulation is great(18.4% had angulation of the sustentacular fragment of >10°, 10.9% had translation of >3 mm),the high prevalences of sustentacular fracture and displacement disprove the ‘‘constant’’ theory of the sustentacular fragment. Lateral and axial view X-ray of the affected foot,and CT scan were taken to evaluate anatomic alignment and integrity of the sustentaculum tali. Combined medial and lateral techniques for calcaneal fixation may be a better choice for comminuted sustentacular fracture. It may affects the reduction and fixation of the fracture. From this sense, we must pay much attention to sustentacular fracture.