载距突的解剖学研究及其在跟骨关节内移位骨折手术中的应用

目的 通过研究跟骨载距突本身及其与周围组织的解剖学关系来设计内固定的最佳位置和角度. 方法①测量正常跟骨的以下指标:载距突的前倾角、跟骨后关节面前部的前倾角、跟骨中部最大宽度、载距突基底部厚度,②观察跟骨内部结构,⑧研究载距突及其周围结构解剖学,④观察跟骨中部螺钉模拟内固定及测量相关角度,⑤随访观察27例经外侧入路切开复位内固定治疗的跟骨关节内移位骨折患者的效果. 结果载距突的前倾角、跟骨后关节面前部的前倾角、跟骨中部最大宽度、载距突基底部最大及最小厚度分别是50°±5°、69°±5°、(41.75±1.76)mm、(12.14±1.60)mm、(4.81±1.07)mm;载距突中关节面下方的骨小梁结构致密,并且与跟骨后关节面下方的致密骨小梁相连续;载距突与走行于其内侧的肌腱血管关系密切;在冠状面上测量自后关节面到载距突的三个进针点打入克氏针的最佳进针方向分别是:最低点向上25°±5°、最高点向下3°±3°、中点向上13°±3°;根据以上测量值进行手术,无患者出现复位或内固定失败的情况,疗效按照美国足踝外科协会后足评分系统评分,优良率为88.9%. 结论载距突是跟骨关节内移位骨折手术时螺钉置入的理想位置,应根据跟骨中部的横径选择螺钉的长度,根据载距突基底部的最小径选择螺钉的直径,根据载距突与后关节面的相互关系决定螺钉的进钉方向,可以获得满意的临床疗效.     

Measurement technique of calcaneal varus from axial view radiograph

Background:

Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle.

Materials and Methods:

52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested.

Results:

Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient.

Conclusion:

Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.     

循原骨折线截骨矫正跟骨骨折畸形愈合

目的 探讨循原骨折线截骨矫正跟骨骨折畸形愈合方法的可行性.方法 2004年8月至2007年5月,跟骨骨折畸形愈合患者25例28足,男23例26足,女2例2足;年龄22～56岁,平均31岁;受伤至手术时间1.5～12个月,平均4.6个月.采用循原骨折线截骨术进行治疗.按照Zwipp和Rammelt跟骨骨折畸形愈合的分类方法进行分类,其中Ⅲ型11例12足,Ⅳ型14例16足.术前均摄双足跟骨侧位、轴位X线片及行CT检查,12例患者(14足)行三维CT重建.根据Sander及Essex-Lopresti分类,参考原始X线片对不同骨折类型制定截骨线,重现原始骨折.根据CT轴位载距突及外侧骨块所带关节面的宽度和轴位骨折线的斜度从前外上到后内下斜行截骨,恢复跟骨的高度,将后关节骨折块向后上撬起,使塌陷的后关节面骨块复位.骨缺损处,用劈下的跟骨外侧壁填塞植骨,或取自体髂骨植骨,最后用钢板螺钉固定.结果 24例26足获得随访,随访时间10～16个月,平均12个月.骨折愈合时间10～14周,平均12周.2例发生伤口感染,经抗生素治疗后10周取出钢板伤口愈合.无一例发生钢板螺钉断裂和骨折再移位.按照Maryland足部评分标准,优10足,良12足,可4足,优良率84%.结论 循原骨折线截骨重现原始骨折,可恢复跟骨的骨性结构,能更好地矫正跟骨各方位畸形,同时保留距下关节,减少了手术对足踝功能的影响,近期疗效满意.     

Fractures of the sustentaculum tali

Objective

Anatomical reconstruction of displaced sustentaculum tali fractures via a direct medial approach.

Indications

Displaced fractures of the sustentaculum tali with incongruity or depression of the medial facet of the subtalar joint, entrapment of the flexor hallucis longus or flexor digitorum longus tendons, fracture line extending into the posterior facet of the subtalar joint.

Contraindications

Infected or grossly contaminated soft tissue, severely restricted vascular supply to the foot, high perioperative risk.

Surgical technique

Direct medial approach over the sustentaculum tali, retraction of the tendons, joint exploration, fracture reduction using the medial facet and cortical outline as guidelines, fracture fixation with two small fragment screws from medial to lateral directed slightly plantarly and posteriorly. Fractures with depression of the medial facet as a whole can alternatively be reduced and fixed percutaneously.

Postoperative management

Lower leg splint for 5–7 days, partial weight-bearing with 20 kg for 6–8 weeks (until radiographic signs of consolidation) in the patient’s own shoewear, early range of motion exercises of the ankle, subtalar and mid-tarsal joints.

Results

Over a course of 15 years, 31 patients were treated operatively for sustentacular fractures. In all, 27 patients (87?%) had additional fractures to the same foot and ankle. Eighteen patients with a mean age of 41 years treated at our institution with screw fixation for a unilateral fracture of the sustentaculum tali could be followed for a mean of 80 months (range 15–151 months). No wound healing problems or infections were seen with the medial approach. At the time of follow-up, 15 sustentaculum tali fractures had an average Foot Function Index of 21.6 and an average AOFAS Ankle–Hindfoot Score of 83.6. Patients with isolated fractures of the sustentaculum tali had significantly better scores than those with additional injuries. In 1 patient, an additional lateral process fracture of the talus required subtalar fusion due to persistent pain. Care must be taken not to overlook these atypical calcaneal fractures and accompanying injuries to the mid-tarsal joint and the lateral talar process as seen in 45% and 23%, respectively, in the present series.     

Morphometric variations of the lateral surface of calcaneus: Can standard plate sizes fit all?

PurposeDisplaced intraarticular fractures of the calcaneum often require plate fixation. The complex fractures are usually fixed with standard lateral plates and are approached via the extensile lateral approach which is fraught with the risk of wound complications. Oversized calcaneal plates produce tension on the wound closure site and can, thus result in wound healing problems. The current study analyses the morphometry of the lateral surface of the calcaneus for the ideal configuration of the calcaneal plates for Indian patients using a CT based analysis of intact calcanei.MethodsFifty CT based studies of normal calcanei were retrospectively analyzed using Horos® software version 3.3.5. The cross-section of the lateral third of calcaneum was assessed for the morphometric measurements relevant to the dimensions of the standard plating devices for calcaneum. We measured the overall plating length of calcaneum, the vertical heights at the anterior process and calcaneal tuberosity, the height of the posterior facet, the lengths of the anterior process, and the posterior facet. The inclination angles of the posterior facet, cuboid facet were also measured. The findings were compared between male and female cases.ResultsThe mean plating length of the calcaneus was 60.06 ± 4.05 mm. The mean vertical height of the anterior process and the calcaneal tuberosity were 24.3 ± 2.71 mm and 39.48 ± 4.73, respectively. The length of the anterior process and the posterior facet were 21.36 ± 1.72 and 25.02 ± 4.17, respectively. The mean Gissane angle and the angle of inclination of posterior facet in relation to the plating length were 118.04 ± 5.99° and 47.3 ± 5.20°. The mean anterior slant angle of the cuboid facet was 96.64 ± 4.39°. Significant differences were observed in the measurements among male and female groups except for the angular parameters.ConclusionThe current analysis suggests the individual morphometric variations of the lateral plating surface of the calcaneus. Although female calcanei have smaller dimensions compared to male calcanei, the angular parameters are comparable among the two groups. Considering the wide variations in the majority of the morphometric parameters, it is difficult to standardize the plate dimensions. However, a few serial increments in the plate dimensions can help in providing the best fit rather than an ideal fit. Also, the plates should be available with multiple inclination angles of the facet limbs according to the local population variations.     

The vascularization of the os calcaneum and the clinical consequences.

This study was conducted to analyze extraosseous and intraosseous vascularization of the os calcaneum and to elucidate possible clinical manifestations. The arteries of 13 lower leg and foot specimens of human cadavers were injected with a polymer and subjected to maceration or were embedded in plastic. The examination revealed that 45% of the bone is vascularized via medial arteries and 45% via lateral arteries, whereas the remaining 10% is supplied by the sinus tarsi artery. From the medial side, two or three vessels branch off the posterior tibial artery, penetrate the calcaneus below the sustentaculum, and supply the medial part of the posterior joint. The lateral calcaneal artery normally is a branch from the posterior tibial artery. In two of 13 specimens, this lateral supply comes from the peroneal artery. The medial and lateral intraosseous arterial supply for the calcaneus is equal. Inside the bone there is a water-shed zone where the medial and lateral arterial supply meet in the midline. Only 10% of the blood flow is supplied by vessels in the sinus tarsi. Clinically, interruption of the lateral calcaneal artery during the conventional lateral surgical approach for a calcaneus fracture may result in ischemic bone necrosis. The lateral calcaneal artery could supply a local microvascular flap to cover soft tissue defects of the heel. A compartment syndrome after a calcaneus fracture may be caused by bleeding from the medial calcaneal arteries into the quadratus plantae compartment.     

2D and 3D assessment of sustentaculum tali screw fixation with or without Screw Targeting Clamp

IntroductionPrecise placement of sustentaculum tali screw(s) is essential for restoring anatomy and biomechanical stability of the calcaneus. This can be challenging due to the small target area and presence of neurovascular structures on the medial side. The aim was to evaluate the precision of positioning of the subchondral posterior facet screw and processus anterior calcanei screw with or without a Screw Targeting Clamp. The secondary aim was to evaluate the added value of peroperative 3D imaging over 2D radiographs alone.MethodsTwenty Anubifix™ embalmed, human anatomic lower limb specimens were used. A subchondral posterior facet screw and a processus anterior calcanei screw were placed using an extended lateral approach. A senior orthopedic trauma surgeon experienced in calcaneal fracture surgery and a senior resident with limited experience in calcaneal surgery performed screw fixation in five specimens with and in five specimens without the clamp. 2D lateral and axial radiographs and a 3D recording were obtained postoperatively. Anatomical dissection was performed postoperatively as a diagnostic golden standard in order to obtain the factual screw positions. Blinded assessment of quality of fixation was performed by two surgeons.ResultsIn 2D, eight screws were considered malpositioned when placed with the targeting device versus nine placed freehand. In 3D recordings, two additional screws were malpositioned in each group as compared to the golden standard. As opposed to the senior surgeon, the senior resident seemed to get the best results using the Screw Targeting Clamp (number of malpositioned screws using freehand was eight, and using the targeting clamp five). In nine out of 20 specimens 3D images provided additional information concerning target area and intra-articular placement. Based on the 3D assessment, five additional screws would have required repositioning. Except for one, all screw positions were rated equally after dissection when compared with 3D examinations.ConclusionThis study does not show a substantial benefit between the Screw Targeting Clamp and the freehand technique as well between experienced and inexperienced surgeons. Data suggest that the clamp might help positioning sustentaculum tali screws, especially for inexperienced surgeons. Perioperative 3D recordings facilitate identification of malpositioned screws.     

正常与畸形愈合跟骨应力分布的比较研究

 目的 探讨在静力载荷作用下,正常与畸形愈合跟骨的应力分布差异。方法 将正常跟骨有限元模型的后关节面由内向外、由前向后楔形切除,模拟骨折后距下关节面塌陷的畸形愈合模型。切除前B?hler角为35°,切除后为0°。自足跟及跟腱附着点处分别垂直向上对模型施加320 N和160 N的载荷,观察畸形愈合跟骨的Vonmises应力分布,并与正常模型进行比较。结果 畸形愈合跟骨的距下关节面应力降低,应力分布特点为从正常的跟骨前中关节面为主要应力区转为跟骨外侧紧靠跟骰关节处,外侧主要应力区要高于内侧,是支撑载荷的主要部位。从跟骨结构的细化比较来看,首先,距下关节面顶部的塌陷造成跟骨主要应力区部分后移,转至跟腱附着点处由正常的(1.51±0.22) MPa增至(3.11±0.24) MPa,而距下关节面顶部的应力由正常的(6.71±0.37) MPa减至(2.83±0.49) MPa。其次,跟骨前侧近跟骰关节处应力明显加大,由正常的(0.46±0.15) MPa增至(2.13±0.15) MPa,载距突应力由5.18 MPa减少至1.41 MPa。结论 跟骨骨折距下关节面塌陷是多数病理变化的主因,在临床治疗中应先解决距下关节面的塌陷问题,恢复跟骨正常高度,跟骨内部应力的分布对解决跟骨骨折后期出现的相关部位疼痛至关重要。     

Fracture dislocation of the calcaneus. A report of two cases

In two typical cases of calcaneal fracture dislocation, the primary fracture, which runs forward and medially from a point behind the sustentaculum tali, is associated with inversion of the hindfoot. The calcaneus splits into a small anteromedial and a larger posterolateral fragment. Rupture of the lateral collateral ligament allows the posterolateral calcaneal fragment to move laterally to lie immediately subjacent to the distal fibula. Closed reduction is impossible. Open reduction of this rare fracture dislocation is essential. A lateral approach to the calcaneus is generally sufficient, but a second medial incision may be required.     

载距突螺钉导向器在跟骨载距突螺钉置钉中的应用

背景：跟骨关节内骨折手术治疗时准确置入载距突螺钉可获得最佳固定效果。但由于跟骨复杂的解剖特点和术中有限的X线透视效果,完成载距突螺钉的准确置钉工作难度极大。而准确置入载距突螺钉的方法仍存较大争议。目的：探讨跟骨关节内骨折手术治疗时使用跟骨载距突螺钉导向器辅助载距突螺钉的准确置钉效果。方法方法：回顾性分析2010年7月至2013年12月手术治疗的42例（48足）跟骨关节内骨折病例,男35例,女7例;年龄15-67岁,平均38.9岁。根据Sanders分型：Ⅱ型22足,Ⅲ型19足,Ⅳ型7足。所有手术均采用跟骨外侧入路,术中使用跟骨载距突螺钉导向器辅助置入跟骨载距突螺钉。术后复查X线与CT,验证螺钉置入载距突的准确性。结果：42例患者术后随访7-28个月,平均17.4个月。按美国足踝外科协会Maryland足部功能评分标准进行功能评定：优21足,良19足,可8足,差0足;术后Maryland足部评分平均为87.8分,优良率83.3%。共置入53枚载距突螺钉。1枚螺钉从跟骨后关节面内下方露出部分螺纹,1枚螺钉从载距突前方穿出,1枚螺钉穿出载距突关节面进入距跟中关节,1枚螺钉远端一半螺纹在载距突下方露出,余49枚螺钉位于载距突内;螺钉置入精确率为92.5%（49/53）。结论：跟骨载距突螺钉导向器能辅助术者从跟骨外侧入路准确完成载距突螺钉置钉。     

Grouping of intraarticular calcaneal fractures relative to treatment options

None of the classifications of intraarticular calcaneal fractures are comprehensive enough to accommodate all types of fractures. Of the 150 intraarticular calcaneal fractures, 37 could not be placed in the commonly used Sanders classification. These then were grouped according to where their primary fracture line was located in relation to the posterior calcaneal facet. Twenty-three fractures were anteromedial to the facet; 75% of these were of the tongue type and were amenable to being treated with the Essex-Lopresti method of reduction and placement of two screws. The joint depression type in this group required open reduction and internal fixation through the lateral approach. Eight fractures were located posterolateral to the facet. They were treated from the lateral or the medial approach. Six fractures crossed the facet transversely; these were treated percutaneously with placement of two lag screws. Clinically this grouping was helpful because it provided a guideline to appropriate treatment strategies for fractures that could not be accommodated in the Sanders classification.     

Osteosynthesis for intra-articular calcaneal fractures

PURPOSE: To correlate treatment results of intra-articular calcaneal fractures with their computed tomographic (CT) classification. METHODS: 36 men and 4 women with 48 intra-articular calcaneal fractures (8 bilateral) underwent open reduction and internal fixation with bone grafting via an extensile lateral approach. Based on 2-dimensional CT scans, the fractures were categorised using the Sanders classification. There were 16 type-II, 20 type-III, and 12 type-IV fractures. Radiographs and Maryland foot scores were used for evaluation of the results at a mean of 38 (range, 26-66) months. RESULTS: Anatomic reduction of the posterior calcaneal facet was achieved in 38 of 48 fractures. The Bohler and Gissane angles were restored to between 92 and 99% of normal, respectively. Despite this, the mean functional scores were 84 in type-II, 83 in type-III and 67 in type-IV fractures. CONCLUSION: Surgical results were superior in type-II and -III fractures. Type-IV fractures fared poorly, despite excellent restoration of calcaneal anatomy; subtalar arthrodesis should have been considered.     

Calcaneus fractures with subluxation of the posterior facet. A surgical indication

The charts and radiographs of 118 patients with 126 intraarticular fractures of the calcaneus were reviewed retrospectively. Eleven of 126 (8.7%) calcaneal fractures had injuries consisting of intraarticular calcaneal fracture, lateral subluxation or dislocation of the posterior facet, fracture extension into the calcaneocuboid joint, peroneal tendon subluxation, subluxation of the talus in the ankle mortise, and complete disruption of the anterior talofibular and calcaneal fibular ligaments or fracture of the lateral malleolus. There were six women and five men. The average age was 40 years (range, 17-65 years). The mechanism of injury was a motor vehicle accident in eight and a fall from a height in three. According to the classification of Sanders et al eight fractures were Type II, one was Type III, and two were Type IV. Followup at an average of 26 months (range, 14-38 months) showed that eight of 11 patients (72.7%) had either good or excellent results. When lateral subluxation of the posterior facet of the calcaneus is identified with a preoperative computed tomography scan, operative management is indicated, and the surgeon should search for associated injuries that should be addressed at the time of surgery.     

跟骨内外侧经皮置针安全区解剖学研究

目的 划定国人跟骨内、外侧外固定针进针位置解剖学相对安全区.方法 解剖14具正常成年人足踝部标本.于跟骨内侧取跟骨最内下后点为A点,内踝最下点为B点,足舟骨结节为C点.解剖出跟骨内侧神经、足底外侧神经最后分支、足底外侧神经、足底内侧神经、胫后动脉、足底外侧动脉和足底内侧动脉.根据各结构行经AB、AC线的位置,确定跟骨内侧的相对安全区;于跟骨外侧取跟骨最外下后点为D点,外踝最下点为E点,解剖出跟骨外侧神经、腓肠神经、小隐静脉主干,同理确定跟骨外侧的相对安全区.结果 跟骨内侧神经、足底外侧神经最后分支、足底外侧神经、足底内侧神经、胫后动脉分别行经AB线后下22%、50%、56%、64%及58%处,跟骨内侧神经、足底外侧神经最后分支、足底外侧神经、足底内侧神经、足底外侧动脉、足底内侧动脉分别行经AC线后下14%、39%、49%、63%、41%及57%处.跟骨外侧神经、腓肠神经、小隐静脉分别行经DE线后下 19%、65%及61%处.结论 在跟骨内侧,AB线后1/2、AC线后1/3所在圆形区域为经皮置针相对安全区.在跟骨外侧,经DE线中点垂线后方的跟骨为经皮穿针相对安全区.     

The Effect of Primary Fracture Line Location on the Pattern and Severity of Intraarticular Calcaneal Fractures: A Retrospective Radiographic Study

This retrospective radiographic study sought to evaluate how primary fracture line location relates to the pattern and severity of intraarticular calcaneal fractures. Preoperative lateral radiographs and semicoronal computed tomography scans of 100 displaced intraarticular calcaneal fractures (89 patients) were evaluated for Bohler's angle, Sanders classification, and calcaneocuboid, anterior, or middle subtalar articular involvement. Primary fracture line location was measured on semicoronal computed tomography views as a ratio of the width of the posterior facet. There were 60 Sanders type II (29 IIA, 29 IIB, 2 IIC), 35 type III (10 IIIAB, 9 IIIAC, 16 IIIBC) and 5 type IV fractures. The mean Bohler's angle was 10.1+/-15.6 degrees. The mean primary fracture line location was calculated to be found at 45.7+/-18.2% of the width of the posterior facet, as measured from lateral to medial. Statistical analysis found a significant association between primary fracture line location and Sanders class (r=.636; P<.001) and Bohler's angle (r=-.287; P=.005); as the fracture line moved medially, comminution increased and Bohler's angle decreased. Forty-eight percent of the fractures involved the calcaneocuboid joint; 39% involved the anterior (n=28) or middle (n=11) subtalar facets, or both. A medial primary fracture line correlated to greater involvement of the calcaneocuboid joint (r=.247; P=.015) and the anterior (r=.241; P<.001) and middle (r=.344; P=.003) facets. These results suggest that intraarticular calcaneal fractures exhibiting a medial primary fracture line are associated with a more severe fracture pattern and an increased incidence of anterior articular extension.     

Sanders Ⅱ型跟骨骨折螺钉微创治疗的有限元优化分析

目的:探讨Sanders Ⅱ型跟骨骨折微创治疗时螺钉不同固定方式后的生物力学特点.方法:将CT 扫描后的跟骨Dicom 数据输入Mimics 21.0 软件及Ansys 15.0 软件中构建跟骨三维有限元数字模型;将此模型导入UG NX 10.0 软件中,根据Sanders 分型切割跟骨,建立后关节面塌陷的Sander...     

Foot Deformity Correction Planning in the Sagittal Plane Based on the Vitruvian Foot First Metatarsal Mechanical Axis and Calcaneus Anatomic Axis

The aim of the study was to test a novel planning method for simultaneous midfoot and hindfoot deformity correction, based on reference lines and angles (RLA) of the talus, calcaneus and first metatarsal in 64 normal radiographs from 55 patients. Talus Joint Line (TJL), from the border of the articular surface of the talus and the posterior process of talus, and mechanical axis of the first metatarsal form the mechanical Lateral Talometatarsal Angle (mLTMA) = 23.6º (±3.2). The length of the first metatarsal line was measured from its intersections with the TJL and first metatarsal head and it was 4.3 (±0.94) times longer that TJL (k). For hindfoot correction planning, we used an axis of the calcaneus formed by a line starting at the middle of the back of the calcaneal tuberosity and going perpendicular to a line from the top point to the bottom point of the calcaneal tuberosity. The intersection of the calcaneal line and the anterior continuation of TJL form the lateral heel angle (LHA) = 15.2º (±3.4).The following parameters were identified: the length from the intersection point of the lines and anterior point of TJL was 2.56 ± 1.1 longer than TJL (k1). The length from the intersection point and posterior border of the calcaneus was 4.59 ± 1.0 times longer than TJL (k2). Planning using the new method was demonstrated and confirmed on 3 case examples. A novel method for analysis and planning of midfoot and hindfoot sagittal plane deformity correction may be used separately or simultaneously for complex deformity correction.     

Morphologic analysis of the subtalar joint using statistical shape modeling

Weightbearing computed tomography (WBCT) enables visualization of the foot and ankle as patients stand under load. Clinical measurements of WBCT images are generally limited to two-dimensions, which reduces the ability to quantify complex morphology of individual osseous structures as well as the alignment between two or more bones. The shape and orientation of the healthy/normal subtalar joint, in particular, is not well-understood, which makes it very difficult to diagnose subtalar pathoanatomy. Herein, we employed statistical shape modeling to evaluate three-dimensional (3D) shape variation, coverage, space, and congruency of the subtalar joint using WBCT data of 27 asymptomatic healthy individuals. The four most relevant findings were: (A) talar and calcaneal anatomical differences were found regarding the presence of (a) the talar posterior process, (b) calcaneal pitch, and (c) curvature of the calcaneal posterior facet; (B) the talar posterior facet articular surface area was significantly greater than the calcaneal posterior facet articular surface area; (C) the posterior facet varied in joint space distance, whereas the anteromedial facet was even; and (D) the posterior and anteromedial facet of the subtalar joint was consistently congruent. Despite considerable shape variation across the population, the posterior and anteromedial articular facets of the subtalar joint were consistently congruent. Results provide a detailed 3D analysis of the subtalar joint under a weightbearing condition in a healthy population which can be used for comparisons to pathological patient populations. The described SSM approach also shows promise for clinical evaluation of the subtalar joint from 3D surface reconstructions of WBCT images.     

A measuremental approach to calcaneal fractures

Objective

The calcaneus is the most frequently broken tarsal bone in the setting of trauma. The diagnosis, treatment and prognosis of calcaneal fractures depend on the location and type determined by the Sanders classification. With the help of measurements on lateral view radiographs like the Böhler’s angle, the angle of Gissane, the calcaneal inclination angle and the calcaneal facet height, we can predict the severity of the trauma and prognosis by assessing the collapse of the calcaneus. On computed tomography (CT), calcaneal fractures which reach into the joint space can be classified by the Sanders classification system according to the number of fragments. In this study, we tried to determine whether calcaneal fracture severity determined by angle and facet height measurements on lateral X-ray radiographs correlate with the Sanders classification.

Materials and methods

Among 69 patients diagnosed with calcaneal fractures, we performed a retrospective study by analysing the Böhler’s angle, the angle of Gissane, the calcaneal inclination angle and the calcaneal facet height on digital lateral X-rays and by classifying the fractures according to the Sanders classification by CT. We compared the results of the two different imaging modalities.

Results

We found that, as the Sanders classification type became more severe from type 1 to type 4, a general decrease was observed in the Böhler’s angle, the inclination angle and the facet length, whereas a general increase was observed for the mean values of the angle of Gissane.

Conclusion

These findings suggest that measurements obtained from lateral X-rays coincide with the Sanders classification and, therefore, might indicate the prognosis.     

The modified Palmer lateral approach for calcaneal fractures: wound healing and postoperative computed tomographic evaluation of fracture reduction

In 32 consecutive intra-articular calcaneal fractures (28 patients, 4 bilateral), open treatment was done using the modified Palmer lateral approach and the reduction was assessed with postoperative radiography and computed tomography (CT) (coronal and axial images, 1-2 days after surgery). Retrospective analysis of the available radiographs and CT scans was done in 27 fractures (25 patients, 2 bilateral) to assess accuracy of reduction achieved; in five fractures the studies were not available. Sanders classification was type I in 2 (7%), type II in 20 (74%), and type III in 5 (19%) fractures; the calcaneocuboid joint was involved in 9 (33%) fractures. Reduction included elevation of the depressed lateral side of the posterior facet, reduction of the neck (anterior third of calcaneus) to the body (middle third of calcaneus), realignment of the posterior tuberosity, and reduction of lateral wall blowout; internal fixation was done with cannulated screws. Mean (+/-SD) values of the following displacement parameters were significantly improved after surgery: B?hler's angle, posterior facet angle, lateral posterior facet articular depression, heel width (coronal CT), and calcaneal height. There was no significant difference between preoperative and postoperative values of mean angle of Gissane, posterior tuberosity position, and body width and length on axial CT. One (3%) of the 32 fractures was associated with preoperative (traumatic) full-thickness skin necrosis at the sinus tarsi that required free muscle flap coverage. One (3%) postoperative wound healing complication occurred, consisting of wound dehiscence and drainage at the central portion of the surgical wound in a smoker, which resolved with dressing changes and antibiotics. In conclusion, the modified Palmer lateral approach enabled open reduction of major features of calcaneal fractures with less soft-tissue risk than more extensile approaches.