CT evaluation of tarsometatarsal fracture-dislocation injuries

Inconsistent radiographic diagnostic criteria for lisfranc injuries: a systematic review

PURPOSE

To evaluate the radiographic diagnostic criteria and propose standardised radiographic criteria for Lisfranc injuries.

METHODS

A systematic review of the PubMed and Embase databases was performed according to the PRISMA guidelines. The various radiographic criteria for the diagnosis of Lisfranc injuries were extracted. Descriptive statistics were presented for all continuous (as mean ± standard deviation) and categorical variables (as frequencies by percentages).

RESULTS

The literature search included 29 studies that totalled 1115 Lisfranc injuries. The risk of bias ranged from "Low" to "Moderate" risk according to the ROBINS-I tool. The overall recommendations according to the GRADE assessment ranged from "Very Low" to "High". 1st metatarsal to 2nd metatarsal diastasis was the most common of the 12 various radiographic diagnostic criteria observed, as was employed in 18 studies. This was followed by 2nd cuneiform to 2nd metatarsal subluxation, as was employed in 11 studies.

CONCLUSION

The radiographic diagnostic criteria of Lisfranc injuries were heterogeneous. The proposition for homogenous radiographic diagnostic criteria is that the following features must be observed for the diagnosis of Lisfranc injuries: 1st metatarsal to 2nd metatarsal diastasis of ≥ 2 mm on anteroposterior view or 2nd cuneiform to 2nd metatarsal subluxation on anteroposterior or oblique views. Further advanced imaging by CT or MRI may be required in patients with normal radiographs but with continued suspicion for Lisfranc injuries.

LEVEL OF EVIDENCE

4, systematic review.

CT and Functional Outcomes of Primarily Ligamentous and Combined Ligamentous-Bony Lisfranc Injuries: A Retrospective Review

Lisfranc injuries have been rising in incidence and can cause significant and lasting morbidity. There is no consensus on the optimal surgical treatment for these injuries, be they primarily ligamentous or combined (bony and ligamentous). No study has ever followed Lisfranc injury patients postoperatively using advanced imaging. The purpose of this study was to compare the functional and radiographic outcomes of primarily ligamentous and combined osseous and ligamentous Lisfranc injuries treated operatively with reduction and fixation. We performed a retrospective review of all Lisfranc injuries treated operatively in a single institution over a 6-year period. Injuries were classified as primarily ligamentous or combined by independent evaluation of available computed tomography (CT) or magnetic resonance imaging. Outcomes were measured using the Short Musculoskeletal Function Assessment (SMFA). CT of 29 patients was performed at last follow-up to evaluate reduction and degenerative changes. Of the 56 patients identified, 38 were available for follow-up. The average follow-up was 3.8 years. There were 26 combined injuries and 12 primarily ligamentous injuries. Outcomes were excellent in all patients and there was no statistical difference in SMFA scores in any category between the groups. On follow-up CT, all injuries were anatomically reduced, and 26 of 29 patients had degenerative changes. Our results support that reduction and stable fixation of Lisfranc injuries may be suitable treatment regardless of classification as combined or primarily ligamentous. Future larger-scale prospective studies should be pursued to supplement existing data.

Outcomes after nonoperatively treated non-displaced Lisfranc injury: a retrospective case series of 55 patients

BACKGROUND

Current knowledge of the role of the nonoperative treatment of Lisfranc injuries is based on a few retrospective case series. Hence, consensus on which patients can be treated nonoperatively does not exist. The aim of this study was to investigate outcomes after nonoperative treatment of Lisfranc injuries.

METHODS

In this study, patients were collected by recruiting all computer tomography-confirmed Lisfranc injuries treated during a 5-year period at a major trauma hospital. Between 2 and 6 years after suffering the injury, patients completed the visual analogue scale foot and ankle questionnaire.

RESULTS

In total, 55 patients returned adequately completed questionnaires and were included in the study. Of those, 22 patients had avulsion fractures and 33 had simple non-displaced intra-articular fractures. Of these patients, 30 (55%) scored over 90 points in both the pain and function subscales of the VAS-FA, and 35 (64%) scored over 90 points overall. In addition, three (5%) patients scored under 60 points in both the pain and function subscales of the VAS-FA, and four (7%) scored under 60 points overall. Only one patient with avulsion fractures underwent secondary surgery.

CONCLUSION

Nonoperative treatment has a role in the treatment of Lisfranc injuries, and the results of our study support the view that avulsion and simple intra-articular fractures with < 2 mm of displacement can be treated nonoperatively with high functional outcomes. The results of nonoperative and operative treatment should be compared in a prospective randomized controlled study setting in future studies.

LEVEL OF EVIDENCE

IV, retrospective case series.

Imaging in Lisfranc injury: a systematic literature review

OBJECTIVES

To systematically review current diagnostic imaging options for assessment of the Lisfranc joint.

MATERIALS AND METHODS

PubMed and ScienceDirect were systematically searched. Thirty articles were subdivided by imaging modality: conventional radiography (17 articles), ultrasonography (six articles), computed tomography (CT) (four articles), and magnetic resonance imaging (MRI) (11 articles). Some articles discussed multiple modalities. The following data were extracted: imaging modality, measurement methods, participant number, sensitivity, specificity, and measurement technique accuracy. Methodological quality was assessed by the QUADAS-2 tool.

RESULTS

Conventional radiography commonly assesses Lisfranc injuries by evaluating the distance between either the first and second metatarsal base (M1-M2) or the medial cuneiform and second metatarsal base (C1-M2) and the congruence between each metatarsal base and its connecting tarsal bone. For ultrasonography, C1-M2 distance and dorsal Lisfranc ligament (DLL) length and thickness are evaluated. CT clarifies tarsometatarsal (TMT) joint alignment and occult fractures obscured on radiographs. Most MRI studies assessed Lisfranc ligament integrity. Overall, included studies show low bias for all domains except patient selection and are applicable to daily practice.

CONCLUSIONS

While conventional radiography can demonstrate frank diastasis at the TMT joints; applying weightbearing can improve the viewer's capacity to detect subtle Lisfranc injury by radiography. Although ultrasonography can evaluate the DLL, its accuracy for diagnosing Lisfranc instability remains unproven. CT is more beneficial than radiography for detecting non-displaced fractures and minimal osseous subluxation. MRI is clearly the best for detecting ligament abnormalities; however, its utility for detecting subtle Lisfranc instability needs further investigation. Overall, the available studies' methodological quality was satisfactory.

Inter- and intraobserver reliability of non-weight-bearing foot radiographs compared with CT in Lisfranc injuries

BACKGROUND

Injury of the tarsometatarsal (TMT) joint complex, known as Lisfranc injury, covers a wide range of injuries from subtle ligamentous injuries to severely displaced crush injuries. Although it is known that these injuries are commonly missed, the literature on the accuracy of the diagnostics is limited. The diagnostic accuracy of non-weight-bearing radiography (inter- or intraobserver reliability), however, has not previously been assessed among patients with Lisfranc injury.

METHODS

One hundred sets of foot radiographs acquired due to acute foot injury were collected and anonymised. The diagnosis of these patients was confirmed with a CT scan. In one-third of the radiographs, there was no Lisfranc injury; in one-third, a nondisplaced (< 2 mm) injury; and in one-third, a displaced injury. The radiographs were assessed independently by three senior orthopaedic surgeons and three orthopaedic surgery residents.

RESULTS

Fleiss kappa (κ) coefficient for interobserver reliability resulted in moderate correlation κ = 0.50 (95% CI: 0.45- 0.55) (first evaluation) and κ = 0.58 (95% CI: 0.52-0.63) (second evaluation). After three months, the evaluation was repeated and the Cohen's kappa (κ) coefficient for intraobserver reliability showed substantial correlation κ = 0.71 (from 0.64 to 0.85). The mean (range) sensitivity was 76.1% (60.6-92.4) and specificity was 85.3% (52.9-100). The sensitivity of subtle injuries was lower than severe injuries (65.4% vs 87.1% p = 0.003).

CONCLUSIONS

Diagnosis of Lisfranc injury based on non-weight-bearing radiographs has moderate agreement between observers and substantial agreement between the same observer in different moments. A substantial number (24%) of injuries are missed if only non-weight-bearing radiographs are used. Nondisplaced injuries were more commonly missed than displaced injuries, and therefore, special caution should be used when the clinical signs are subtle.

LEVEL OF EVIDENCE

III.

The Role of Percutaneous Reduction and Fixation of Lisfranc Injuries

To be able to perform percutaneous fixation of Lisfranc injuries, this article emphasizes that an anatomic reduction must be mandatory. When uncertainty remains as to whether closed reduction is anatomic, formal open reduction is recommended because accuracy of reduction is correlated with long-term outcome. Closed injuries with minimal displacement, bony avulsions, and skeletally immature individuals seem the most appropriate indications for percutaneous fixation. Not all injuries are ideal for this method of treatment, and this is an area that needs to be more clearly defined in the future.

Comparison of treatment results of acute and late injuries of the lisfranc joint

Objective

A retrospective comparison of treatment difficulties and treatment outcomes in Lisfranc joint injuries with late and early diagnosis.

Methods

The study group consisted of 10 patients diagnosed and treated properly within six months to 20 years of the accident causing the injury (mean six years). The control group consisted of the same number of randomly selected patients with a similar type of injury treated immediately after the accident. Mean follow-up was 13 years in the study group and eight years in the control group. The analysis evaluated the causes of the delay and the foot function at the time of follow up, measured using the AOFAS Midfoot Scale and the Lublin Foot Functional Score. The scores of the patients were analyzed using the non-parametric Mann-Whitney U test and the non-parametric Wilcoxon test.

Results

The control group had statistically significantly better scores on both scales.

Conclusion

The main cause of treatment delay was misdiagnosis by the primary care physician. Level of Evidence III, Retrospective Comparative Study.

Age, sex, causal and injury patterns in tarsometatarsal dislocations: a literature review of over 2000 cases

BACKGROUND

The causes and mechanisms of tarsometatarsal (TMT) dislocations are poorly characterized. Unfortunately, the rarity of these injuries makes it difficult and costly to gather the epidemiological data needed to better understand the populations at risk and the circumstances under which injury is most likely to occur.

METHODOLOGY

To address this issue, literature reports of TMT dislocations were identified and analyzed to generate statistical descriptions of the common causes of injury, the age and sex of those injured, and the pattern of injury. Over 2000 injuries were identified from 187 articles.

RESULTS

The analysis reveals that over 40% of injuries were related to traffic accidents. Based on the Hardcastle classification system, more than 60% of TMT dislocation were partial (type B) injuries. Over 55% of the injured were between 15 and 35 years of age, and males were injured more than twice as frequently. Conversely, the victims of falls tended to be older and represented a larger proportion of females. The age and sex of those injured by TMT dislocations vary by cause.

CONCLUSION

An improved understanding of the epidemiologic patterns will benefit research into the mitigation and prevention of these injuries.

Modified anteroposterior and oblique radiographs of the midfoot and their efficiency in demonstrating the tarsometatarsal joints

AIM

To assess whether conventional and modified anteroposterior and oblique radiographs of the midfoot can be used to demonstrate tarsometatarsal (TMT) joints clearly.

MATERIALS AND METHODS

Conventional anteroposterior and oblique radiographs of the midfoot were taken of 152 volunteers. Modified radiographs of the midfoot were taken of 14 volunteers by tilting the radiographic system tube and placing volunteers' feet on different footboards. Both conventional and modified radiographs were taken of 27 patients with midfoot injuries to demonstrate the injuries to the TMT joints. Two radiologists assessed the radiological demonstration of the TMT joints. Statistical analyses were performed using SPSS 13.0 for Windows.

RESULTS

Conventional radiographs of the midfoot did not sufficiently clearly demonstrate TMT joints. They could not demonstrate the majority of the TMT joints. The modified anteroposterior radiographs of the midfoot taken with the radiographic system tube tilted 30° towards the calcaneus demonstrated most TMT joints clearly. The modified oblique radiographs taken with the foot placed on a 30° footboard and with the radiographic system tube tilted 20° towards the calcaneus also showed the majority of TMT joints clearly. For the evaluation of midfoot injuries, modified radiographs perform better than conventional radiographs.

CONCLUSIONS

Modified anteroposterior and oblique radiographs, which allow clear detection of the articulation and trabeculae of TMT joints, are valuable alternatives when assessing TMT joints.

The diagnostic accuracy of radiographs in Lisfranc injury and the potential value of a craniocaudal projection

OBJECTIVE

The purpose of this study is to determine the diagnostic accuracy of radiographs in the diagnosis of Lisfranc injury. In addition, a foot phantom was investigated to determine the optimum degree of craniocaudal angulation on the anteroposterior radiograph to best show the joint. The angle of the joint in patients with midfoot injury was investigated to determine the optimum degree of craniocaudal angulation.

MATERIALS AND METHODS

Sixty patients examined by CT had their radiographs evaluated independently and by consensus opinion by two observers, and the diagnostic performance was calculated using CT as the reference standard. A foot phantom was radiographed with varying degrees of craniocaudal angulation, and the radiograph that best revealed the joint was determined. This was compared with the angle of the joint as measured on CT. The angle of the joint in all 60 patients was measured on CT.

RESULTS

The radiographs correctly identified 31 of the 45 cases (68.9%) of Lisfranc injury, with a positive predictive value of 84.4%, a negative predictive value of 53.3%, a sensitivity of 84.4%, and a specificity of 53.3%. Twenty degrees of craniocaudal angulation best showed the second tarsal-metatarsal joint of the phantom, and this correlated with a 20° angle measured by CT. The mean (± SD) angle of the joint in the patients was 28.9° ± 5.7°.

CONCLUSION

Conventional radiographs miss a significant number of cases of Lisfranc injury. Craniocaudal angulation can better show the joint, and an angle of 28.9° is likely to optimally visualize the joint in the majority of patients.

Sonographic evaluation of Lisfranc ligament injuries

OBJECTIVE

This study characterized the sonographic appearances of Lisfranc injuries.

METHODS

Sonography reports (2000-2007) were searched for "Lisfranc," resulting in 10 patients. Sonographic images of affected and asymptomatic contralateral feet were reviewed, recording the thickness of the dorsal ligament between the first (medial) cuneiform (C1) and second metatarsal (M2) ligaments, distance between C1 and M2, and change in this distance with weight bearing, hyperemia, and fractures. Correlations were made to clinical, surgical, and other imaging findings.

RESULTS

In 5 asymptomatic feet, the dorsal C1-M2 ligament was 0.9 to 1.2 mm thick, and the C1-M2 distance was 0.5 to 1 mm. Of the symptomatic feet, 1 group (n=3) had normal sonographic findings (thickness, 0.9-1.1 mm; distance, 0.6-0.7 mm; all had normal radiographic findings and follow-up, and 1 had normal magnetic resonance imaging [MRI] findings). Another group (n=3) had abnormal hypoechogenicity and thickening of the dorsal C1-M2 ligament (1.4-2.3 mm), a normal C1-M2 distance (0.6-0.7 mm), and no widening with weight bearing (1 of 1), consistent with a ligament sprain (1 had normal computed tomographic [CT] findings, and all had uneventful follow-up). The third group (n=4) had nonvisualization of the dorsal C1-M2 ligament, an increased C1-M2 distance of 2.5 to 3.1 mm, and further widening with weight bearing (3 of 4) from Lisfranc ligament disruption (shown at surgery in 2, MRI in 1, and CT in 1).

CONCLUSIONS

Nonvisualization of the dorsal C1-M2 ligament and a C1-M2 distance of 2.5 mm or greater were indirect signs of a Lisfranc ligament tear. Dynamic evaluation with weight bearing showed widening of the space between C1 and M2.

Sprains—residual instability of subtalar, Lisfranc joints, and turf toe

Sprains of the hindfoot, midfoot and forefoot are being diagnosed with more regularity in athletes. Each of these injuries can go on to develop chronic instability with associated disability. With early diagnosis and appropriate treatment significant morbidity and loss of playing time can be avoided. Knowledge of the relevant anatomy, mechanism of injury, and available diagnostic tools is essential for making the proper diagnosis. Once the correct diagnosis is made, proper treatment can be implemented to avoid long term complications of instability.

Injury to the tarsometatarsal joint complex

Tarsometatarsal joint complex fracture-dislocations may result from direct or indirect trauma. Direct injuries are usually the result of a crush and may involve associated compartment syndrome, significant soft-tissue injury, and open fracture-dislocation. Indirect injuries are often the result of an axial load to the plantarflexed foot. Midfoot pain after even a minor forefoot injury should raise suspicion; up to 20% of tarsometatarsal joint complex injuries are missed on initial examination. An anteroposterior radiograph with abduction stress may reveal subtle injury, but computed tomography is the preferred imaging modality. The goal of treatment is the restoration of a pain-free, functional foot. The preferred treatment is open reduction and internal fixation, using screw fixation for the medial three rays and Kirschner wires for the fourth and fifth tarsometatarsal joints. Satisfactory outcome can be expected in approximately 90% of patients.

Complications of missed or untreated Lisfranc injuries

Injuries to the Lisfranc complex are fairly common. Delayed treatment or missed diagnosis of these injuries can lead to significant complications. Non-operative treatment and salvage surgery can help to relieve sequelae that are associated with tarsometatarsal arthritis following traumatic injury.

Classification, investigation, and management of midfoot sprains: Lisfranc injuries in the athlete

BACKGROUND

Midfoot sprains in athletes represent a spectrum of injuries to the Lisfranc ligament complex, from partial sprains with no displacement to complete tears with frank diastasis. Treatment of these injuries varies from the treatment of high-velocity injuries seen in nonathletes.

PURPOSE

We wanted to report the outcome of treatment in athletes with Lisfranc injuries classified according to our system.

STUDY DESIGN

Retrospective cohort study.

METHODS

Weightbearing radiographs and bone scintigrams were used to diagnose midfoot sprains in 15 athletes who were treated surgically or nonoperatively according to the following classification: nonoperative management for stage I injuries (undisplaced) and anatomic reduction with fixation for stage II (diastasis with no arch height loss) and stage III (diastasis with arch height loss) injuries.

RESULTS

We achieved an excellent outcome in 93% of 15 athletes with midfoot sprains at an average follow-up of 27 months (range, 9 to 72).

CONCLUSIONS

Weightbearing radiographs and bone scintigrams are sensitive, reproducible, and relatively inexpensive methods of investigation of these injuries. Restoration and maintenance of the anatomic alignment of the Lisfranc joint is the key to appropriate treatment of injury to the midfoot.

Pericuboid fracture-dislocation with cuboid subluxation

The case of a 44-year-old male with a traumatic pericuboid fracture-dislocation consisting of disruption of the midtarsal, tarsometatarsal and pericuboid articulations is presented. The cuboid was partially dislocated without cuboid fracture. Treatment consisted of open reduction with stable internal fixation followed by early range of motion and protected weight-bearing for 12 weeks. Functional outcome results were excellent at final follow-up.

Developments and advances in the diagnosis and treatment of injuries to the tarsometatarsal joint

Continued research and clinical advances have allowed clinicians to diagnose injuries of the tarsometatarsal joint earlier and with greater precision than in previous eras and have promoted refinements of the surgical procedures used in their treatment. For patients with such injuries, these advances should result in improved function and a substantial decrease in morbidity.

Optimal computed tomography imaging of the midfoot: an improved technique

A new protocol for computed tomography (CT) imaging of the midfoot is described. This imaging technique places the CT cuts parallel to and perpendicular to the talus-first metatarsal axis, as viewed on the lateral CT scout image. For imaging the midfoot, this technique is an improvement over previously described hindfoot or midfoot protocols.

Radiographic and computed tomographic evaluation of Lisfranc dislocation: a cadaver study

Six cadaver feet were used for radiological and computed tomographic (CT) evaluation. The tarsometatarsal joints of each specimen were displaced dorsolaterally in successive 1-mm increments. None of the 1-mm and two thirds of the 2-mm dorsolateral Lisfranc dislocations could be visualized on routine radiographs; they could all be noted on CT scans. There was good assessment on CT scan for the extent of the minor lesions that are normally obscured by overlapping projection in routine radiographs. A Lisfranc injury that appears undisplaced on radiographs or acceptable after closed reduction may still have an unpredictable outcome because of the presence of an occult joint subluxation. CT scanning is more sensitive than radiography for detecting the minor amounts of Lisfranc displacement. If there is any doubt on the radiographs, a CT scan should be performed. The early diagnosis and treatment of Lisfranc injuries may minimize development of post-traumatic degenerative arthritis.

Computer evaluation of second tarsometatarsal joint dislocation

Using computer-assisted techniques, this study analyzes the mean contact area of the articular surface of the second tarsometatarsal joint. The articular contact area decreased proportionate to the displacement in both males and females, but it was consistently greater in males than in females for all simulated displacements. The reduction in the contact area was the highest with dorsolateral displacement compared with the lateral and dorsal displacements. Dorsolateral displacement of the second metatarsal of 3 mm led to 38.6% reduction in the contact area, compared with 33.1% and 20.2% reduction with lateral and dorsal displacements, respectively. This study shows that even minor degrees of displacement not apparent on plain radiographs lead to significant decrease in the contact area of the second tarsometatarsal joint. Careful evaluation of second tarsometatarsal injuries with computed tomography is recommended to detect minor degrees of displacement.

Organized chaos? Computed tomographic evaluation of the neuropathic diabetic foot

Accurate radiographic evaluation of diabetic neuroarthropathy is increasingly difficult as the disease becomes more florid. 22 patients with a known diabetic neuroarthropathy of one or both feet were prospectively examined by computed tomography (CT) in the axial and coronal planes. Bilateral changes of a neuroarthropathy were present in 75% of cases. Distinct patterns of disease were seen and categorized into five types in order of increasing severity. Changes at the medial tarsometatarsal joints and adjacent intercuneiform joints were seen in all affected feet. More extensive disease involved the medial arch more commonly than the lateral. Fractures of the tarsal bones were found in 32% of cases and were associated with neuroarthropathic changes in adjacent joints. Calcaneal fractures were seen in four feet. A Lisfranc fracture-dislocation was present in 41% of cases and a bilateral in only 21%. A single CT examination of the foot, while an accurate method of demonstrating the extent of the disease, is an insensitive indicator of disease activity.

Rupture of Lisfranc's ligament in athletes

Ligamentous injuries to the tarsometatarsal joints are uncommon and usually result from violent trauma to the forefoot. A more subtle tarsometatarsal injury consisting of an isolated diastasis of the first and second tarsometatarsal rays has recently been described. This injury is thought to be caused by a rupture of Lisfranc's ligament. Nine injuries that occurred during athletics are described. History and physical findings are crucial for arousing the clinician's suspicion for this injury, but confirmation can best be obtained by comparison weight-bearing radiographs; the space between the first and second metatarsal bases may be widened 2 to 5 mm. Nonoperative treatment consisting of casting and the use of crutches for 4 to 6 weeks was successful in returning patients back to athletics; however, the time to return to competition averaged 4 months.

Fractures and dislocations of the foot

The incidence and severity of fractures and dislocations vary depending on their location and on the direction of the forces responsible for the injury. The radiologist's role in evaluation of the injured foot is to recognize the types of injuries produced by particular forces. Because there is considerable overlap of fractures and dislocations of the foot and ankle, evaluation of one area to the neglect of the other can lead to significant oversights and failure to recognize additional injury patterns. For example, fractures of the talus, calcaneus, base of the fifth metatarsal, and to a lesser extent, the cuboid and navicular bones may masquerade as ankle sprains or malleolar injuries. The most important aspects to correct interpretation of traumatized foot radiographs are (1) pertinent clinical history, (2) a complete radiographic series, and (3) detection of soft-tissue swelling or injury.

Tarsometatarsal joint injuries in the athlete

This is a retrospective review of the presentation, diagnosis, treatment, and outcome of 19 patients who injured the tarsometatarsal joint of the foot during athletic activity. Diagnosis by clinical and radiographic examination was supplemented by stress fluoroscopy of the articulation under anesthesia. Injuries were classified as either a first- or second-degree sprain of the tarsometatarsal joint, a third-degree sprain (with diastasis between the metatarsals or cuneiforms), a fracture, or frank dislocation. Poor functional results were seen in those for whom diagnosis was delayed and for whom the injury was not treated adequately. Three patients were unable to return to sports, one of whom eventually required fusion of the tarsometatarsal joint. The third-degree sprains were indistinguishable from fracture and fracture-dislocations in that good results were not reliably obtained by nonoperative treatment, and both classes of injury seem to require open reduction and internal fixation for optimal return to function. The delay in return to full activity is a marker of the severity of this injury despite an often benign appearance on radiograph.

Fracture-dislocations of the tarsometatarsal joint, a combined anatomical and computed tomographic study

Based on anatomical and computed tomographic data as well as experience with the treatment of 30 patients with fracture-dislocation of the tarsometatarsal (Lisfranc) joint, a pathophysiological model is described in which the shape of the foot and ligamentous configuration in combination with applied forces are of pivotal importance. CT imaging helps to elucidate the extent of the lesions, easily overlooked in straight radiographs. In the transverse plane we discern three grades of dislocation. Grade 1, virtually no displacement; grade 2, dislocation of half of the shaft; grade 3, total displacement. Treatment is generally dictated by the severity of the lesion and ranges from plaster application to open reduction and internal fixation. Quality of reduction is easily visualized with CT imaging.