Lateral ankle radiographs: do we really understand what we are seeing?

Development of a Surgical Difficulty Score for Open Reduction Internal Fixation of Pilon Fractures

OBJECTIVES

To identify characteristics that contribute to surgical complexity in pilon fractures and to develop a machine learning (ML) Pilon Surgical Difficulty Score (PSDS) based on these factors.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Academic Level I trauma center.

PATIENT SELECTION CRITERIA

Pilon fractures (OTA/AO Type 43) in adult patients treated with open reduction internal fixation.

OUTCOMES MEASURES AND COMPARISONS

Various patient, injury, and radiological characteristics were assessed. Surgical difficulty was measured using 2 outcomes: (1) operative time and (2) perceived difficulty. Perceived difficulty was determined using the opinion of 16 fellowship-trained orthopaedic traumatologists on a 10-point scale. Significant predictors of difficulty were determined using univariate analyses. ML models were used to develop a PSDS for both operative time and surgical difficulty.

RESULTS

One hundred operatively fixed pilon fractures were included. Predictors of operative time were age, OTA/AO classification, articular comminution, articular impaction, bone loss, delay to surgery, poor quality reduction, number of approaches, and number of articular fragments. Predictors of perceived difficulty included OTA/AO classification and delay to surgery. Operative time PSDS had a mean absolute error of 64 minutes and a 60-minute buffer accuracy of 59%. Perceived difficulty PSDS had a mean absolute error of 1.7 points and a 2-point buffer accuracy of 63%.

CONCLUSION

ML was used to generate accurate PSDSs for operative time and difficulty for pilon fractures. Future work should aim to clinically validate these PSDSs, so they may improve patient outcomes.

LEVEL OF EVIDENCE

Level III Diagnostic.

Influence of reduction quality on functional outcome and quality of life in the surgical treatment of tibial plateau fractures: A retrospective cohort study

BACKGROUND

Despite a substantial improvement in the operative treatment of tibial plateau fractures, the surgical procedure remains controversial and is generally challenging, as patients may develop postoperative arthritis and functional impairment of the knee joint.

HYPOTHESIS

In the surgical treatment of tibial plateau fractures the intraoperative reposition quality has the greatest influence on the postoperative outcome, whereby misalignments of≥2mm lead to a worse result.

PATIENTS AND METHODS

Forty-one patients with tibial plateau fractures were postoperatively examined. The operative treatment was performed under reduction control using an intraoperative 3D C-arm. The follow-up collective was divided into two groups depending on the intraoperative reduction result. The postoperative results were then evaluated using the following parameters: Lysholm score, Rasmussen score, Tegner score, SF-36 score, range of motion and pain level.

RESULTS

Group 1 (articular surface incongruencies<2mm) tended to achieve a better result in all scores than group 2 (articular surface incongruencies≥2mm), in the Lysholm score (p=0.039), in the comparison of the range of motion (p=0.012) and the pain level (p=0.039) this was significant. Group 1 achieved an average of 90.71 points (group 2: 78.74) in the Lysholm score. The average range of motion of the knee joint was 138.93° in group 1 (group 2: 127.78°). The average value of the current pain level in group 1 was 1.14 (group 2: 2.63).

DISCUSSION

Both study groups achieved a very good result compared to the available literature. It appears that reduction quality - which can be analyzed with intraoperative 3D imaging - plays the most important role in postoperative quality of life and functional outcome. Intraoperative adjustments of the reduction should therefore be performed on joint surface irregularities with a size above 2mm.

LEVEL OF EVIDENCE

III; retrospective case control study.

Evaluation of Software-Based Metal Artifact Reduction in Intraoperative 3D Imaging of the Spine Using a Mobile Cone Beam CT

The aim of our study was to evaluate whether software-based artifact reduction can achieve an improved image quality, using intraoperative 3D imaging in spinal surgery. A total of 49 intraoperative 3D image datasets of patients, who underwent surgery with pedicle screw placement, were retrospectively evaluated. The visibility of anatomical structures and the diameter of the pedicle screws were examined, with and without the application of the artifact reduction software. All software prototypes can improve the visibility of anatomical structures (P < 0.01), except MAR (metal artifact reduction) combined with IRIS (iterative reconstruction in image space) (P = 0.04). The algorithms MAR and MAR-2 can reduce the blooming artifacts significantly (P < 0.01), but SL (Shepp & Logan) cannot (P = 0.08-0.988). In summary, software-based artifact reduction for intraoperative 3D datasets can improve the current image quality. Additional information regarding the implant placement and the fracture reduction is therefore generated for the surgeon.

Weight-Bearing CT Scan After Tibial Pilon Fracture Demonstrates Significant Early Joint-Space Narrowing

BACKGROUND

Posttraumatic osteoarthritis (PTOA) is a common and early sequela of tibial pilon fractures resulting in substantial long-term disability. New approaches are needed to objectively and reliably quantify early disease progression in order to critically assess the impact of interventions aimed at preventing or mitigating PTOA. Weight-bearing computed tomography (WBCT) scans provide a means for measuring joint space while the ankle is in a loaded, functional position. We assessed the interrater and intrarater reliability of a standardized, regional method to quantify joint-space loss following tibial pilon fracture compared with the uninjured contralateral ankle.

METHODS

We prospectively enrolled 20 patients with intra-articular tibial pilon fractures that were surgically treated at 1 of 2 level-I trauma centers. Six months after injury, bilateral ankle WBCT scans were obtained. Joint space was measured by 4 reviewers at 9 discrete regions of the tibiotalar articulation on sagittal images. Measurements were repeated by reviewers 2 weeks later. To characterize the measurement method, interrater correlation coefficient estimates and test-retest reproducibility were calculated.

RESULTS

The mean tibiotalar joint space was 21% less in the injured ankles compared with the contralateral uninjured ankles (p < 0.0001). The middle-lateral and middle-central regions of the joint demonstrated the greatest decrease in joint space between injured and uninured ankles. The interrater correlation coefficient of the measurement technique was 0.88, and the test-retest reproducibility was 0.80, indicating good reliability and reproducibility of the method.

CONCLUSIONS

We developed a simple, standardized, and reliable technique to quantify tibiotalar joint space following tibial pilon fracture on WBCT. Significant loss of joint space is seen 6 months after the injury. This tool can be used to longitudinally quantify loss of joint space following pilon fracture and assess the impact of interventions to reduce PTOA.

Does surgical approach affect sagittal plane alignment and pilon fracture outcomes?

PURPOSE

Sagittal plane alignment beyond articular reduction and its effect on clinical outcomes has not been emphasized. Surgical approach may influence a surgeon's ability to correct the sagittal plane alignment. The purpose of our study was to evaluate how surgical approach impacts anterior distal tibial angle (ADTA) and lateral talar station (LTS). Our hypothesis was that the anterolateral (AL) approach would improve the sagittal plane parameters due to the primary plate placement.

PATIENTS AND METHODS

A retrospective review was performed on patients who underwent operative management for pilon fractures at 2 ACS Level 1 Academic Trauma Centers. Clinical data points including demographics, comorbidities, AO/OTA classification, surgical approach, and complications were recorded. Quality of reduction was measured using the ADTA, lateral distal tibia angle (LDTA), and lateral talar station (LTS) from radiographs.

RESULTS

580 pilon fractures met inclusion criteria. When compared to the AL approach, the modified anteromedial (AM) approach had decreased rates of local wound care, and unplanned reoperations. The AM approach had increased rates of superficial infection, deep infection, non-union, and amputations. There was no difference in ADTA, LDTA, or LTS between the AM and AL approach (P = 0.49, P = 0.41, P = 0.85). There was a difference in LTS with tobacco users (P = 0.02).

CONCLUSIONS

The sagittal plane alignment does not appear to be affected by the surgical approach. Therefore, the surgical approach to pilon fractures should be based on the fracture pattern and the patient's soft tissue envelope. This study shows that the AM is a relatively safe and effective approach to complex fractures and the surgeon should consider the specific fracture pattern and patient soft tissue envelope when choosing the specific approach.

Understanding the Radiographic Anatomy of the Proximal Ulna and Avoiding Inadvertent Intraarticular Screw Placement

OBJECTIVES

To map the proximal ulnar articular margins and ensure safe extraarticular placement of implants.

METHODS

Ten fresh frozen adult elbow cadaver specimens were obtained. Radiopaque wire was applied to the articular margin of the articular facets and the central trochlear ridge of the proximal ulna. Fluoroscopic images were obtained demonstrating the articular facet margins. Radiographic measurements were performed and used to identify relative safe screw zones.

RESULTS

All specimens demonstrated marked extension of the ulnar and radial facets dorsal to the central trochlear ridge. The dorsal extent of the ulnar facets from the central trochlear ridge averaged 9.7 mm (range, 7.9-13 mm; SD, 1.5 mm) and 6.2 mm (range, 3.4-9.4 mm; SD, 1.9 mm), respectively. The average footprint of the posterior ulnar facet occupied 44% (±4.9%) of the total ulnar height from the dorsal cortex to the trochlear ridge.

CONCLUSIONS

The articular margins of the anterior and posterior facets of the proximal ulna are challenging to identify radiographically. A surgical "at-risk zone" exists within 9.7 mm from the radiographic margin of the central trochlear ridge. Implants placed within this zone have the potential to violate the articular surface.

Influence of reduction quality on functional outcome and quality of life in treatment of tibial plafond fractures: a retrospective cohort study

Background

The aim of the study was to evaluate the impact of reduction quality, using intraoperative 3D imaging, on quality of life and functional outcome in the operative treatment of tibial plafond fractures.

Methods

A group of patients with tibial plafond fractures was re-examined. The operative treatment was performed between September 2001 and October 2011. The follow-up examination was at least 2 years after the final surgical procedure. Final reduction result was assessed intraoperatively using a mobile 3D C-arm. A categorization with regard to descriptive parameters as well as type and size of joint surface irregularities was performed. Follow-up results were evaluated using: Olerud and Molander (O & M) score, Short-Form-36 (SF-36) score, movement deficit, Kellgren and Lawrence grade of osteoarthritis, and pain intensity.

Results

34 patients with operatively treated tibial plafond fracture could be re-examined. Reduction quality had the greatest influence on functional result measured by the O & M score (p = 0.001) and the PCS domain of the SF-36 score (p = 0.018).

Significant differences with regard to O & M score (p = 0.000), SF-36 score (p = 0.001 to p = 0.02; without MCS domain), movement deficit (p = 0.001), grade of osteoarthritis (p = 0.005) and pain (p = 0.001) could be verified under consideration of the reduction quality. The group with the anatomically more accurate reduction also showed a better result for clinical follow-up and quality of life. Furthermore, it is not the type of joint surface irregularity that is always decisive, but rather the size.

Conclusions

Despite other relevant factors, it appears that reduction quality –which can be analyzed with intraoperative 3D imaging– plays the most important role in postoperative quality of life and functional outcome. Corrections should therefore be performed on joint surface irregularities with a size above 2 mm.

Evaluating the Utility of the Lateral Elbow Radiograph in Central Articular Olecranon Reduction: An Anatomic and Radiographic Study

OBJECTIVES

The surgical reduction of intra-articular olecranon fractures is judged primarily on the lateral elbow radiograph, as orthogonal imaging of the articular surface is not obtainable. We sought to determine surgeon accuracy in identifying intra-articular olecranon malreductions on the lateral elbow radiograph.

METHODS

Six human fresh-frozen cadaveric elbow specimens were sagittally sectioned in 5-mm increments after olecranon dissection, preservation of soft tissue envelope, and rigid fixation of the elbow in an external fixator. Three patterns of central intra-articular olecranon malreduction were created in each elbow using a ruler and bone saw. Perfect lateral elbow radiographs were taken of each malreduction, and these images were randomized along with x-rays of normal cadaveric olecranons. The image series was presented to 4 masked trauma-trained surgeons to determine whether the olecranon was malreduced or anatomic. Surgeons interpreted the same image series on 2 separate occasions separated by 6 weeks. Percent correct was recorded, and the interobserver and intraobserver reliability was calculated.

RESULTS

Orthopedic trauma surgeons correctly identified olecranon malreductions only 73% of the time on the lateral elbow radiograph. Interobserver agreement was moderate for the first review of images and fair for the second review, with respective Fleiss Kappa values of 0.43 and 0.28. Intrarater reliability revealed moderate agreement with Cohen's Kappa value ranging from 0.56 to 0.66.

CONCLUSIONS

Intra-articular olecranon malreductions are inconsistently recognized by trauma surgeons on the lateral elbow radiograph. Therefore, articular incongruity may still be present after surgical fixation of comminuted olecranon fractures. We must further define the radiographic anatomic representation of the articular olecranon to improve surgical reduction and clinical outcomes.

Can MRI accurately detect pilon articular malreduction? A quantitative comparison between CT and 3T MRI bone models

BACKGROUND

Pilon fracture reduction is a challenging surgery. Radiographs are commonly used to assess the quality of reduction, but are limited in revealing the remaining bone incongruities. The study aimed to develop a method in quantifying articular malreductions using 3D computed tomography (CT) and magnetic resonance imaging (MRI) models.

METHODS

CT and MRI data were acquired using three pairs of human cadaveric ankle specimens. Common tibial pilon fractures were simulated by performing osteotomies to the ankle specimens. Five of the created fractures [three AO type-B (43-B1), and two AO type-C (43-C1) fractures] were then reduced and stabilised using titanium implants, then rescanned. All datasets were reconstructed into CT and MRI models, and were analysed in regards to intra-articular steps and gaps, surface deviations, malrotations and maltranslations of the bone fragments.

RESULTS

Initial results reveal that type B fracture CT and MRI models differed by ~0.2 (step), ~0.18 (surface deviations), ~0.56° (rotation) and ~0.4 mm (translation). Type C fracture MRI models showed metal artefacts extending to the articular surface, thus unsuitable for analysis. Type C fracture CT models differed from their CT and MRI contralateral models by ~0.15 (surface deviation), ~1.63° (rotation) and ~0.4 mm (translation).

CONCLUSIONS

Type B fracture MRI models were comparable to CT and may potentially be used for the postoperative assessment of articular reduction on a case-to-case basis.

Beam Projection Effect in the Radiographic Evaluation of Ankle Valgus Deformity Associated With Fibular Shortening

BACKGROUND

Fibular shortening is one of the most common causes of ankle valgus deformity in children, and is frequently observed in patients with hereditary multiple exostoses (HME). It has been observed that the lateral distal tibial angle (LDTA) measured on the teleoradiograph differs from that on the ankle anteroposterior (AP) radiograph. The effect of the beam projection angle in the measurement of ankle valgus deformity associated with fibular shortening in HME patients was investigated.

METHODS

Fourteen ankles showing valgus deformity associated with fibular shortening from 14 HME patients comprised the short fibula group. Nineteen ankles with normal ankle alignment from 19 patients comprised the control group. The LDTA on the AP radiograph, teleoradiograph, and 3 coronal planes of 3-dimensional computed tomographic scans were measured and compared.

RESULTS

In the short fibula group, the LDTA measured on the ankle AP radiograph was significantly larger than that on the teleoradiograph (79.6±4.3 vs. 75.0±6.2 degrees, P=0.001), whereas there was no significant difference in the control group (P=0.36). In the short fibula group, the LDTAs measured on the 3 coronal planes of 3-dimensional computed tomography showed that the ankle valgus measurement significantly increased from anterior to posterior planes (P=0.001), whereas there was no significant difference in the control group (P=0.85).

CONCLUSIONS

Measurement of ankle valgus deformity depends on the direction of beam projection and ankle valgus deformity is more severe in the posterior coronal plane of the ankle joint. This discrepancy should be taken into consideration in the planning of ankle valgus deformity management.

LEVEL OF EVIDENCE

Level IV-diagnostic.

Impact of Intraoperative Cone Beam Computed Tomography on Reduction Quality and Implant Position in Treatment of Tibial Plafond Fractures

BACKGROUND

The intraoperative assessment of the articular surface in displaced intra-articular distal tibia fractures can be challenging using conventional fluoroscopy. The aim of the study was to determine the frequency and the method of intraoperative corrections of fracture reductions or implant placements during open reduction, internal fixation by using cone beam computed tomography (CT) after conventional fluoroscopy.

METHODS

Displaced intra-articular distal tibia fractures were retrospectively analyzed from August 2001 until December 2011. The fractures were classified according to the standards of the AO/OTA as type B or C and treated with open reduction and internal plate fixation. After primary reduction using conventional fluoroscopy, an additional cone beam CT scan was used to determine the alignment of the joint line and the implant position. The number of intraoperative revisions of the primary reduction due to the use of cone beam CT was analyzed.

RESULTS

A total of 143 patients with an intra-articular tibial plafond fracture were included in the analysis. In 43 patients (30%), an intraoperative correction was performed after the cone beam CT scan. In 34 (24%) of these cases, intraoperative correction was required because of inadequate joint line reduction. Nine (6%) corrections were required as a result of a malposition of the implant. The revision rate did not differ by fracture classification.

CONCLUSION

Despite its acceptance as the standard method of imaging, intraoperative conventional fluoroscopy for the assessment of implant positioning and fracture reduction of tibial plafond fractures is limited. The intraoperative utilization of cone beam CT provided additional information for the surgeon to detect insufficient reduction or implant malposition.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Reliability of measurements on lateral ankle radiographs

Background

The aims of our study were to evaluate the validation of measurement of weight-bearing lateral radiographs. Two hypotheses were tested: the measurements on the lateral radiographs are reliable, and a theoretical limit could be identified when a surgeon can “eyeball” an incongruous ankle joint on lateral radiographs.

Methods

To test the first hypothesis, 3 experienced ankle surgeons evaluated 50 normal weight-bearing lateral radiographs of patients. The measurements assessed were the tibial lateral surface angle (TLS), the distance from the center of the talar joint circle to the longitudinal axis of the tibia (x) and the displacement from the center of the talar articular joint circle to the center of the distal tibia articular joint circle (d). To test the second hypothesis, we used CAD software to create schematic diagrams on which lateral radiographs of the ankle joint were not parallel (d = 1, 2, 3, 4 mm). Five experienced ankle surgeons were asked to judge whether the ankle articular surfaces were parallel. Intraobserver reliability was determined using the intraclass correlation coefficients (ICCs) and interobserver agreement by the Kendall coefficient of concordance.

Results

First, the intraobserver reliability was high (Cronbach’s alpha >0.80) with regard to radiographic measurements according to the ICC. Significant interobserver disagreement was found (Kendall tauB, p < 0.01) using the Kendall concordance coefficient. Second, when the d-value was 4 mm, all the observers identified the incongruous ankle joint at two separate times.

Conclusions

Consultation with experienced foot and ankle surgeons and precise definitions for lateral measurement assessments do not guarantee a high level of agreement. Surgeons can observe an incongruous ankle joint on lateral radiographs when the d-value is 4 mm.

How much articular displacement can be detected using fluoroscopy for tibial plateau fractures?

INTRODUCTION

While there is conflicting evidence regarding the importance of anatomic reduction for tibial plateau fractures, there are currently no studies that analyse our ability to grade reduction based on fluoroscopic imaging. The purpose of this study was to determine the accuracy of fluoroscopy in judging tibial plateau articular reduction.

METHODS

Ten embalmed human cadavers were selected. The lateral plateau was sagitally sectioned, and the joint was reduced under direct visualization. Lateral, anterior-posterior (AP), and joint line fluoroscopic views were obtained. The same fluoroscopic views were obtained with 2mm displacement and 5mm displacement. The images were randomised, and eight orthopaedic traumatologists were asked whether the plateau was reduced. Within each pair of conditions (view and displacement from 0mm to 5mm) sensitivity, specificity, and intraclass correlations (ICC) were evaluated.

RESULTS

The AP-lateral view with 5mm displacement yielded the highest accuracy for detecting reduction at 90% (95% CI: 83-94%). For the other conditions, accuracy ranged from (37-83%). Sensitivity was highest for the reduced lateral view (79%, 95% CI: 57-91%). Specificity was highest in the AP-lateral view 98% (95% CI: 93-99%) for 5mm step-off. ICC was perfect for the AP-lateral view with 5mm displacement, but otherwise agreement ranged from poor to moderate at ICC=0.09-0.46. Finally, there was no additional benefit to including the joint-line view with the AP and lateral views.

CONCLUSION

Using both AP and lateral views for 5mm displacement had the highest accuracy, specificity, and ICC. Outside of this scenario, agreement was poor to moderate and accuracy was low. Applying this clinically, direct visualization of the articular surface may be necessary to ensure malreduction less than 5mm.

Assessing the bilateral geometrical differences of the tibia--are they the same?

Contralateral bones are often used in many medical applications but it is assumed that their bilateral differences are insignificant. Previous studies used a limited number of distance measurements in quantifying the corresponding differences; therefore, little is known about their bilateral 3D surface asymmetries. The aim of the study is to develop a comprehensive method to quantify geometrical asymmetries between the left and right tibia in order to provide first results on whether the contralateral tibia can be used as an equivalent reference. In this study, 3D bone models were reconstructed from CT scans of seven tibiae pairs, and 34 variables consisting of 2D and 3D measurements were measured from various anatomical regions. All 2D measurements, and lateral plateau and distal subchondral bone surface measurements showed insignificant differences (p>0.05), but the rest of the surfaces showed significant differences (p<0.05). Our results suggest that the contralateral tibia can be used as a reference especially in surgical applications such as articular reconstructions since the bilateral differences in the subchondral bone surfaces were less than 0.3mm. The method can also be potentially transferable to other relevant studies that require the accurate quantification of bone bilateral asymmetries.

Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D

Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in operative techniques should be considered.

[Intraoperative 3-dimensional imaging - beneficial or necessary?]

BACKGROUND

With reference to two large retrospective studies we would like to make a contribution to the discussion whether intraoperative 3-dimensional imaging is only a helpful tool or state of the art for some special indications.

METHODS

To answer this question the intraoperative revision rates of syndesmotic injuries and calcaneal fractures were analyzed over a period of 10 years and 8 years, respectively. Additionally, the clinical outcome was evaluated depending on the restoration of the joint reconstruction.

RESULTS

Intraoperative revision rates of 32.7 % of 251 syndesmotic injuries and 40.3 % of 377 calcaneal fractures were found. The mutivariate analysis showed that residual joint incongruity leads to significantly worse clinical and radiological outcome of calcaneal fractures.

CONCLUSIONS

Correct assessment of alignment and joint line reconstruction are not possible by means of fluoroscopy in every case of syndesmotic injuries and calcaneal fractures. Therefore, intraoperative 3-dimensional imaging should be used in the treatment of these injuries due to the high intraoperative revision rates and the clinical relevance.

Articular congruity is associated with short-term clinical outcomes of operatively treated SER IV ankle fractures

BACKGROUND

With regard to supination-external rotation type-IV (SER IV) ankle fractures, there is no consensus regarding which patient, injury, and treatment variables most strongly influence clinical outcome. The purpose of this investigation was to examine the impact of articular surface congruity on the functional outcomes of operatively treatment of SER IV ankle fractures.

METHODS

A prospectively generated database consisting of operatively treated SER IV ankle fractures was reviewed. Postoperative computed tomography (CT) scans were used to assess ankle joint congruity. Ankles were considered incongruent in the presence of &gt;2 mm of articular step-off, intra-articular loose bodies, or an articular surface gap of &gt;2 mm (despite an otherwise anatomic reduction) due to joint impaction and comminution. Patients with at least one year of clinical follow-up were eligible for analysis. The primary and secondary outcome measures were the Foot and Ankle Outcome Score (FAOS) and ankle motion.

RESULTS

One hundred and eight SER IV fractures met our inclusion criteria. The average duration of follow-up was twenty-one months. Seventy-two patients (67%) had a congruent ankle joint, and thirty-six (33%) had elements of articular surface incongruity on postoperative CT scanning. These two groups were similar with regard to comorbidities and injury and treatment variables. At the time of the final follow-up, the group with articular incongruity had a significantly worse FAOS with regard to symptoms (p = 0.012), pain (p = 0.004), and activities of daily living (p = 0.038). Those with articular incongruity had worse average scores in the FAOS sport domain as well. No significant differences in ankle motion were found between the two groups.

CONCLUSIONS

In this population of patients with an operatively treated SER IV ankle fracture, the presence of postoperative articular incongruity correlated with inferior early clinical outcomes. Orthopaedic surgeons should scrutinize ankle fracture reductions and strive for perfection to allow for the best possible clinical outcome.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Malleolar fractures and their ligamentous injury equivalents have similar outcomes in supination-external rotation type IV fractures of the ankle treated by anatomical internal fixation

It has previously been suggested that among unstable ankle fractures, the presence of a malleolar fracture is associated with a worse outcome than a corresponding ligamentous injury. However, previous studies have included heterogeneous groups of injury. The purpose of this study was to determine whether any specific pattern of bony and/or ligamentous injury among a series of supination-external rotation type IV (SER IV) ankle fractures treated with anatomical fixation was associated with a worse outcome.

We analysed a prospective cohort of 108 SER IV ankle fractures with a follow-up of one year. Pre-operative radiographs and MRIs were undertaken to characterise precisely the pattern of injury. Operative treatment included fixation of all malleolar fractures. Post-operative CT was used to assess reduction. The primary and secondary outcome measures were the Foot and Ankle Outcome Score (FAOS) and the range of movement of the ankle.

There were no clinically relevant differences between the four possible SER IV fracture pattern groups with regard to the FAOS or range of movement. In this population of strictly defined SER IV ankle injuries, the presence of a malleolar fracture was not associated with a significantly worse clinical outcome than its ligamentous injury counterpart. Other factors inherent to the injury and treatment may play a more important role in predicting outcome.