The effect of fibular malreduction on contact pressures in an ankle fracture malunion model

Surgical Correction of Large Talar Tilt in Varus Ankle Osteoarthritis: Lessons from Clinical Experience and a Review of the Literature

Numerous studies exist on medial opening wedge supramalleolar osteotomy (SMO), ever since its introduction by Takakura et al., as a joint-preserving surgical option for treating varus ankle osteoarthritis (OA). Although SMO can induce lateral translation of the talus-which is medially translated in varus ankle OA-it has only minimal effects on the correction of the varus tilt of the talus. Particularly, SMO alone does not effectively neutralize the talar position. The primary reason for this limitation is that varus tilting of the talus is not merely a two-dimensional deformity in the coronal plane, but rather a three-dimensional deformity involving internal rotation and anterior subluxation. Therefore, this study aimed to explore the key considerations for achieving effective correction of varus talar tilt in joint-preserving surgery for treating degenerative varus ankle OA with large talar tilting. Further, we have discussed the relevant studies and included the lessons learned from our clinical experience, categorizing the key surgical considerations into preoperative, intraoperative, and postoperative phases.

[Fractures of the upper ankle joint]

Fractures of the upper ankle joint are frequent injuries and part of routine clinical trauma surgery. In recent years, treatment strategies have changed in different ways due to advances in imaging diagnostics and a better understanding of the biomechanics. In addition, new implant systems are available. The goals of the reconstruction are anatomical reduction with restoration of the joint anatomy, reconstruction of the length, rotation and axial relationships as well as the restoration of stable joint guidance. In addition to the bony reconstruction, the focus is on restoring ligamentous instabilities. Keywords that are increasingly more in focus and controversial are: the posterior malleolar fragment, syndesmosis instability, the fourth malleolus and the importance of the deltoid ligament. For a good long-term result, anatomical reconstruction remains the basic requirement, regardless of the methods used.

Fibular Malunion: Diagnosis, Treatment, and Prevention

Malunions of the fibula are caused by malreduction during initial surgical management or the result of nonoperative treatment of an unstable ankle fracture. They can cause significant changes in loading of the ankle and subsequently lead to arthritic changes. Timely recognition of abnormal anatomy and corrective osteotomy yields favorable results. The current review addresses the anatomy and biomechanics of the ankle and the effects of a malunited fibula fracture. The radiological workup is discussed as well as the technique of the osteotomy. Last, the authors highlight the expected outcome and possible complications for an optimal informed consent of the patient.

Critical factors in enhancing the correction efficacy for varus talar tilt in patients with varus ankle osteoarthritis: relative fibular shortening to the tibia and syndesmotic widening

INTRODUCTION

Relative fibular shortening compared to the tibia and syndesmotic widening are recognized contributors to the valgus tilt of the talus. This study aimed to assess: (1) the impact of fibular shortening relative to the tibia; and (2) the influence of syndesmotic widening, in correcting a large varus talar tilt (TT) associated with advanced ankle osteoarthritis through medial opening wedge valgization supramalleolar osteotomy (SMO).

MATERIALS AND METHODS

We retrospectively reviewed the clinico-radiographic findings of 41 patients with a preoperative TT of 8 degrees or more who underwent SMO for varus ankle osteoarthritis, with a minimum follow-up of more than two years. We compared several clinico-radiographic parameters between the three groups based on postoperative TT changes (decreased TT by 2 degrees or more, no TT changes [TT change between - 2 and 2 degrees], and increased TT by 2 degrees or more).

RESULTS

In total, 18, 16, and 7 patients were included in the groups with postoperative decreased TT, no TT changes, and postoperative increased TT, respectively. The postoperative talocrural angle was greater in the postoperative increased TT group than in the postoperative decreased TT group (P =.036). The postoperative tibiofibular clear space was greatest in the postoperative decreased TT group (P =.037), whereas the other two groups were not significantly different (P =.260). In the postoperative increased TT group, postoperative tibial plafond inclination was the lowest among the three groups (P =.048 and 0.023, respectively), indicating the greatest plafond valgus inclination to the ground. All postoperative clinical parameters were significantly lower in the postoperative increased TT group (P <.05).

CONCLUSION

When performing SMO for varus ankle osteoarthritis, TT correction might be associated with the relative length of the fibula to the tibia and the role of the syndesmosis, implying the need for fibular shortening/valgization and syndesmotic widening. Additionally, excessive correction during SMO that places the tibial plafond in a valgus position relative to the ground floor can paradoxically increase TT and exacerbate ankle osteoarthritis.

LEVEL OF EVIDENCE

Level III.

Mini Fragment and Small Fragment Screws are Comparable in Acute Syndesmotic Injury

Ankle fractures are often accompanied by syndesmotic injuries, contributing to instability and potential long term complications. Syndesmotic injuries are traditionally fixed with either small fragment (3.5-mm diameter) or large fragment (4.5-mm diameter) syndesmotic screws. With regards to the recent emergence of less prominent implants for ankle fracture, this study was set out to compare the outcomes of mini fragment screws (2.7-mm or 2.8-mm diameter) and small fragment screws in syndesmotic fixation. Eighty-seven patients with traumatic syndesmotic injuries were retrospectively included for this study. Forty-four patients underwent mini fragment fixation and 43 patients underwent standard small fragment fixation. After-treatment was similar in both groups. Primary outcome consisted of the incidence of malreduction and secondary dislocation within three months. Secondary objectives were the incidence of the overall complication rate and implant removal rate. In total, malreduction was observed in three patients (3.4 %) and secondary dislocation in two patients (2.3 %), with no significant differences between the mini fragment and small fragment groups. Mini fragment fixation demonstrated a significantly lower overall complication rate (2.3 %) compared to the small fragment group (16.3 %)(p = .030). Implant removal rates were similar between the groups (27.3 % for mini fragment and 27.9 % for small fragment screws). This study suggests that both screw types are effective for fixation of acute syndesmotic injuries, with comparable malreduction and secondary dislocation rates. Prospective studies with longer follow-up, including functional outcome, are needed for comprehensive insights into optimal syndesmotic screw selection.

The Impact of Fibular Fixation Method on Pilon Fracture Healing

Background: Pilon fractures are associated with high-energy injuries, and there is presently much debate as to optimal fixation strategies and timing of intervention. There is little evidence comparing the type of fibular fixation during pilon fracture fixation. The purpose of this study was to compare fibular fixation methods in complex pilon injuries as it relates to pilon union rates and development of post-traumatic arthritis. Methods: This was a retrospective review from an urban Level 1 trauma center from January 2009 to May 2019, including patients age ≥ 18 who sustained a pilon fracture with an associated fibula fracture. Patients were allocated into one of three groups based on fibular fracture treated with plating, intramedullary device, or no fixation. Radiographic analysis was performed postoperatively and at final follow up to evaluate for tibial or fibular nonunion, malunion, talocrural angle, and ankle Kellgren-Lawrence grade. Results: Of the 107 patients in this study, 42 underwent surgical fixation of their fibular fracture. There were no differences with respect to tibial or fibular union rates amongst the three groups. Furthermore, there were no differences in the presence of radiographic ankle arthritis at final follow up. However, Kellgren-Lawrence arthritis grading did appear to be a more severe grade in patients who did not undergo fibular fixation (p = 0.001). Conclusions: Fibular intramedullary fixation does not appear to influence tibial or fibular nonunion rates as compared to plating in complex pilon injuries.

Weightbearing Computed Tomography Evaluation of Acute SER4a Ankle Fractures

BACKGROUND

Supination external rotation (SER) fibula fractures with abnormal medial clear space (MCS) on stress radiographs that normalizes with weightbearing radiographs, termed SER4a ankle fractures, pose a challenge in treatment decision making. This study aims to quantify differences in joint contact area, tibiotalar rotation, and translation using weightbearing computed tomography (CT) scans in SER4a ankle fractures.

METHODS

Between November 2022 and September 2023, patients presenting with isolated Weber B fibula fractures were evaluated for inclusion. Adult patients presenting within 10 days of injury with an SER4a ankle fracture, and no history of ankle fractures or surgery, were included. Ten patients were enrolled and underwent bilateral ankle weightbearing CT scans. Disior Bonelogic Software was used to quantify joint contact area, tibiotalar rotation, and translation, with the uninjured ankle serving as the control.

RESULTS

Ten patients (4 male, 6 female) with an average age of 51 years were included. The average MCS measured 2.5 mm (SD 0.36) on weightbearing and 5.7 mm (SD 0.67) on stress radiographs. The difference in joint contact area between injured and healthy joints was 12.2 mm2 (P = .085). Axial tibiotalar joint rotation averaged 6.6 degrees of increased external rotation on the injured extremity (P < .001). The mediolateral distance between the center of the tibial plafond and center of the talar dome was increased 1.0 mm in the injured extremity (P < .05).

CONCLUSION

In this study evaluating 10 patients with acute SER4a ankle fractures, no difference in joint contact area was found between individuals' healthy and injured ankles. However, differences in external rotation and lateral translation of the talus were observed on the injured ankle. The clinical effects of these tibiotalar rotational and translational changes are unknown.

CLINICAL RELEVANCE

This study provides insight regarding in vivo changes in 3-dimensional alignment of SER4a ankle fractures that may influence future management of these fractures.

Radiographic Accuracy of Identifying Anterolateral Tibial Plafond Involvement in Pronation Abduction Ankle Fractures

OBJECTIVES

To evaluate the incidence of anterolateral tibial plafond involvement in pronation-abduction (PAB) ankle fractures and analyze the accuracy of radiographs in detecting anterolateral tibial plafond involvement, impaction, and predicting the need for direct visualization and an articular reduction.

METHODS

DESIGN

A multi-institutional retrospective chart review.

SETTING

Five Level 1 trauma centers in the United States.

PATIENT SELECTION CRITERIA

Adult patients with PAB ankle fractures (OTA/AO 44B2.3, 44C2.2, 44C2.3) from 2020 to 2022 were reviewed by 7 fellowship-trained orthopaedic trauma surgeons. They were queried about the presence of anterolateral tibial plafond involvement and impaction, and whether they would need direct visualization and an articular reduction using both radiographs and CT.

OUTCOME MEASUREMENTS AND COMPARISONS

The presence of anterolateral tibial plafond impaction was tabulated separately using radiographs and CT scans. The accuracy of radiographs and changes in surgical plan after CT review were calculated using CT as the gold standard.

RESULTS

Sixty-one fractures in 61 patients were evaluated using CT and/or plain radiographs. Using plain radiographs, anterolateral tibial plafond involvement and impaction were identified in 61% and 36% of cases, respectively. In the 38 fractures with both plain radiographs and CT scans, anterolateral tibial plafond involvement was identified in 66% of radiographs and 74% of CT scans ( P = 0.4). Plafond impaction was identified in 42% of plain radiographs and 37% of CT scans ( P = 0.62). There was no difference in the rate of involvement between radiographs and CT scan. The diagnosis of anterolateral tibial plafond impaction using plain radiographs was correct in 74% of fractures when compared with using CT imaging, resulting in a sensitivity of 71%, a specificity of 75%, a positive predictive value (PPV) of 62%, and a negative predictive value (NPV) of 82%. Plain radiographs correctly predicted the need for direct visualization and an articular reduction in 74% of cases and had a PPV of 59% and an NPV of 86%.

CONCLUSIONS

Anterolateral tibial plafond involvement and impaction were present on CT in 74% and 37% of pronation-abduction (PAB) ankle fractures, respectively. Plain radiographs had higher NPV for identifying impaction and the need for articular reduction than they did sensitivity, specificity, or PPV. CT is an important tool for preoperative planning that should be considered when planning for operative fixation of PAB ankle fractures.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Fibular Malrotation on Tibiotalar Joint Contact Mechanics in a Weber B Ankle Fracture Model

BACKGROUND

In minimally displaced Weber B ankle fractures, the distal fibular fracture fragment can be externally rotated. This malrotation is difficult to detect on radiographs and, when left malreduced through nonoperative treatment, may contribute to altered joint mechanics, predisposing to posttraumatic osteoarthritis. This study evaluates the effects of fibular malrotation on tibiotalar joint contact mechanics.

METHODS

Six cadaveric ankles were tested using a materials testing system (MTS) machine. A tibiotalar joint sensor recorded contact area and pressure. Samples were tested in the intact, neutrally rotated, and malrotated state. Each trial applied a 686N axial load and a 147N Achilles tendon load in neutral position, 15° dorsiflexion, and 15° plantarflexion.

RESULTS

In the comparison of malrotated to intact ankles, peak contact pressure was found to be significantly greater at neutral flexion (intact 5.56 MPa ± 1.39, malrotated 7.21 MPa ± 1.07, P = .03), not significantly different in dorsiflexion, and significantly decreased in plantarflexion (intact 11.2 MPa ± 3.04, malrotated 9.01 MPa ± 1.84, P = .01). Significant differences in contact area were not found between conditions.

CONCLUSION

The findings suggest that fibular malrotation contributes to significant alterations in tibiotalar joint contact pressures, which may contribute to the development of posttraumatic osteoarthritis. When malrotation of the fibula is suspected on plain radiographs, a computer tomography (CT) scan should be obtained to evaluate its extent and further consideration should be given to surgical treatment.

LEVELS OF EVIDENCE

Level V: Bench testing.

Radiologic evaluation of ankle fracture malunions of the fibula

Ankle fractures involving the distal fibula are common injuries. Malreductions and subsequent malunions of the distal fibula can result in worse clinical outcomes and posttraumatic arthritis. The ability to accurately evaluate and identify malreductions and malunions of the distal fibula is important. A number of different radiographic and CT measurements have been described to assess fibular length and rotation. This review highlights various radiologic measures and discusses their advantages and limitations.

Biplane Reduction: A Novel Technique for Restoring Fibula Length in Maisonneuve Fracture

OBJECTIVE

Fibular length is important for ankle stability. Failure to adequately restore and stabilize fibula length may result in malunion, hindering postoperative functional exercises and recovery of ankle function. However, there is no unified and effective reduction method for fibular shortening in Maisonneuve fractures. In this study, we introduce the biplane reduction as an effective surgical technique for restoring the length of the fibula in Maisonneuve fractures.

METHODS

This retrospective study enrolled 12 patients preoperatively diagnosed with Maisonneuve fractures between June 2019 and June 2022. All patients underwent our biplane reduction technique to restore the length of their fibula. Operation time, hospital stay, complications, FTA (the angle between the fibular tip and the superior articular surface of the talus), visual analog pain score, and the American Orthopaedic Foot and Ankle Society ankle-hindfoot score were recorded. An independent sample t-test was used for component comparisons, and a paired sample t-test or one-way analysis of variance was used for intra-group comparisons.

RESULTS

No patient was lost to follow-up and no obvious postoperative complications were observed. After operation, FTA recovered from 37.52 ± 0.37 ° to 40.42 ± 0.43 °, which was significantly improved compared with that before operation (p < 0.01). At the last follow-up, both the VAS and AOFAS scores showed significant improvement compared to pre-surgery scores.

CONCLUSIONS

The reduction technique proposed in this study to restore the length of the fibula in Maisonneuve fractures is simple and effective, does not require special equipment, and has the advantage of directly examining the reduction condition.

Joint preserving procedures for Takakura stage IIIB varus ankle osteoarthritis

A man in his early 70s with right Takakura stage IIIB varus ankle osteoarthritis underwent medial opening wedge supramalleolar osteotomy with inframalleolar correction as joint preserving procedure. We also performed anteroinferior tibiofibular ligament (AITFL) resection with fibular shortening valgisation osteotomy to enhance the talar tilt correction. Postoperative decrease in talar tilt with dramatic symptom improvement was achieved. Performing the AITFL resection with fibular shortening valgisation osteotomy plus concomitant supramalleolar osteotomy and inframalleolar correction for Takakura stage IIIB varus ankle osteoarthritis resulted in successful improvement in talar tilt by making room for the valgus deviation of the talus.

Better outcomes using suture button compared to screw fixation in talofibular syndesmotic injuries of the ankle: a level I evidence-based meta-analysis

INTRODUCTION

The present meta-analysis evaluated current level I clinical trials which compared the use of a suture button (SB) versus syndesmotic screw (SS) fixation techniques for syndesmosis injuries of the ankle. The outcomes of interest were to compare patient-reported outcome measures (PROMs) and complications. It was hypothesised that SB might achieve better PROMs along with a lower rate of complications.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, PubMed, Web of Science, Google Scholar, and Embase were accessed. All the randomised controlled trials (RCTs) which compared SB versus SS fixation for syndesmosis injuries of the ankle were accessed. Data concerning the American Orthopaedic Foot & Ankle Society (AOFAS), and Olerud-Molander score (OMS) were collected at baseline and at last follow-up. Data on implant failure, implant removal, and joint malreduction were also retrieved.

RESULTS

Data from seven RCTs (490 patients) were collected. 33% (161 of 490) were women. The mean length of the follow-up was 30.8 ± 27.4 months. The mean age of the patients was 41.1 ± 4.1 years. Between the two groups (SB and SS), comparability was found in the mean age, and men:women ratio. The SS group evidenced lower OMS (P = 0.0006) and lower AOFAS (P = 0.03). The SS group evidenced a greater rate of implant failure (P = 0.0003), implant removal (P = 0.0005), and malreduction (P = 0.04).

CONCLUSION

Suture button fixation might perform better than the syndesmotic screw fixation in syndesmotic injuries of the ankle.

Factors Associated With Adverse Radiographic Outcomes Following Operative Management of Ankle Fractures: A Single-Center Study

Introduction Ankle fractures are commonly encountered fractures in emergency departments worldwide. These fractures often have significant articular involvement that requires anatomic surgical reduction and stabilization. Radiographs can be used in everyday practice to evaluate ankle fractures utilizing various parameters to assess reduction quality intraoperatively and postoperatively. Several factors have been found to influence the reduction quality of fractures across body regions. This retrospective study aimed to evaluate the influence of several factors on the reduction quality of ankle fractures in a tertiary care center in the Kingdom of Bahrain. Materials and methods A total of 462 records were identified during the search, and 68 records were excluded. A total of 394 ankle fractures met the inclusion criteria for the study. Five orthopedic surgeons then evaluated the operative films in accordance with the Delphi consensus parameters for evaluating ankle fractures, and the reductions were graded as good, adequate, or poor. Results The study included 394 ankle fractures that met the inclusion criteria, and four significant associations were noted to affect the quality of reduction. Ankle fractures with posterior malleolus involvement (PMI) were significantly associated (p = 0.001) with fragments smaller than 15% and larger than 20% having decreased outcomes. The number of days from admission to operation was also significant (p = 0.009), with the best reductions observed between zero and one day from admission. Operating surgeon was also a significant factor (p = 0.038), with inferior reductions noted in specialist surgeons compared to trainees. The last significant association was the number of malleoli (p = 0.001), with an inferior reduction with a larger number of malleoli involved. Conclusion Ankle fractures are a common and significant orthopedic injury. Reduction quality is important for optimal outcomes after surgical stabilization. Various factors including the number of malleoli, the grade of the operating surgeon, and the time of surgery were significantly related to the quality reduction in this single-center study. Expedited surgical management of fractures that are amenable to early fixation, careful assessment, and meticulous technique in fixation of fractures with multiple fractured malleoli is indicated to reduce the chance of malreduction particularly in complex injuries. Further assessment of factors related to reduction quality with large-scale prospective studies would provide orthopedic surgeons with insights into the identification and optimal treatment of such fractures.

Chronic Deltoid Insufficiency in Stage IV Adult Acquired Flatfoot Deformity: Do We Have a Good Answer?

Stage IV adult acquired flatfoot deformity (AAFD) with secondary chronic deltoid ligament insufficiency is a challenging deformity to treat, with minimal consensus in the literature concerning its surgical management. Many surgical treatment options have been described, including joint-sparing techniques, fusions, osteotomies, and even arthroplasties. However, questions remain as to what, if any, treatment is optimal. This contribution reviews studies on surgical treatments for stage IV AAFD with deltoid ligament failure and provides a critical analysis regarding the quality of outcomes reported for those different treatment options. PubMed and Google Scholar databases were searched between June 1, 2022, and August 15, 2022, for studies published between 1990 and 2022 that describe the treatment of stage IV AAFD with deltoid ligament insufficiency. Articles included in the study focused on subjects with stage IV AAFD and associated deltoid ligament insufficiency undergoing surgical correction. Exclusion criteria included stage I, II, and III AAFD, as well as deltoid ligament repair following acute injury/rupture. Nine studies covering five different treatment options for patients with stage IV AAFD and chronic deltoid insufficiency were included, with minimal overlap in outcome measures used to assess the efficacy of the procedure. Triple arthrodesis with deltoid ligament reconstruction resulted in a 62.5% (5/8) success rate with a residual tibiotalar (TT) angulation of 2° (success defined as <3°). Tibiotalar arthrodesis of four patients resulted in an average post-operative tibiotalar angulation of 4.8° with all patients showing progressive destabilization of the hindfoot complex at 12-18 year follow-ups. Deltoid arthroscopic laminoplasty (Brostrom) resulted in an increased American Orthopaedic Foot and Ankle Society (AOFAS) score from 49.7 pre-op to 91.9 post-op. There was no long-term follow-up of these patients. Deltoid ligament reconstruction using autografts of the peroneus longus resulted in a post-operative valgus of 2.1° in one study and <5° in another. Deltoid ligament reconstruction using an anterior tibial tendon autograft resulted in a gain of 126.4 + 40.2% in stiffness compared to an intact ligament. Twinfix suture anchors resulted in a post-operative hindfoot angle averaging 5.3°. Combined deltoid and spring ligament reconstruction resulted in a 5.1° valgus angulation. There is currently no standard of care or clinical consensus regarding surgical treatment for stage IV AAFD with deltoid insufficiency. Several studies imply that mild valgus malalignment around the tibiotalar joint can result in satisfactory outcomes. A few studies even deemed <5° of valgus tilt post-operatively successful. However, it has been described that any imbalance in tibiotalar tilt is a significant risk factor for progressive arthritis and future ligamentous failure. No treatment option was able to correct valgus tilt to an anatomical standard (i.e., to normal anatomy). These varied findings, along with the lack of consensus on post-surgical measures to assess efficacy, are worrisome and emphasize the need for better surgical options. Moreover, there is a critical need for additional research on the long-term outcomes following stage IV AAFD and deltoid insufficiency repair, particularly, as over five million people in the United States and 10% of the geriatric population are affected by AAFD with a risk of progressing to stage IV.

Management of Pediatric Supination-inversion Ankle Injuries Involving Distal Tibia and Intraepiphyseal Distal Fibula Fractures

Pediatric ankle fractures are prevalent injuries that make up a notable portion of all periphyseal injuries. The Salter-Harris classification is the most popular classification about physeal and periepiphyseal injuries. Ogden expanded on this and described type 7 fractures which are completely intraepiphyseal and include propagation of the fracture from the articular surface through the epiphyseal cartilage and do not involve the physis. These injuries are common about the distal fibula in pediatric patients with supination-inversion type injuries. There are no specific guidelines or recommendations on treatment of these injuries in the literature. We present three cases of this injury pattern and describe our chosen management that leads each patient to full, painless ankle range of motion and return to all prior activities and sports without complication. Supination-inversion type pediatric ankle fractures are common injuries that all orthopaedic surgeons will encounter at some point throughout their practice or training. Recognizing fracture variants and understanding treatment options of pediatric ankle fractures are important for the orthopaedic community as a whole.

Measuring External Rotation of the Fibula and Fibular Length in Bilateral Computed Tomography Scans: How Reliable Is This Method?

OBJECTIVES

During ankle fracture surgery, goals include accurate reduction and fixation of the fibula regarding rotation and fibular length. Bilateral postoperative computed tomography (CT) can be performed to assess fibular rotation using the talar dome angle, and fibular length. The aim of this study was to compare side-to-side differences of the fibular rotation and fibular length using bilateral CT scans of uninjured ankles.

METHODS

DESIGN

Retrospective.

SETTING

Single center, Level I Academic Trauma Center.

PATIENT SELECTION CRITERIA

Patients with bilateral CT scans of uninjured ankles.

OUTCOME MEASURES AND COMPARISONS

External rotation using the Nault talar dome method and fibular length using the coronal method of Prior et al. The average, difference, and ratio (injured side/healthy side) and interobserver variability were calculated.

RESULTS

There were 83 patients included (166 ankles, mean age 47 years, 77.1% male). A random set of 66 ankles (33 CT scans) were used to measure interobserver variability. The mean degrees of external rotation ranged from 6.6 to 7.7, mean difference ranged from 1.4 to 3.4 degrees, mean ratio ranged from 1.1 to 1.5, and interobserver variability ranged from 0.27 to 0.65. For fibular length, the mean ranged from 24.6 to 25.8 mm, mean difference in fibular length ranged from 0.5 to 2.1 mm, mean ratio ranged from 1.0 to 1.1 mm, and interobserver variability ranged from 0.45 to 0.73.

CONCLUSIONS

Using bilateral ankle CT scans, mean differences in fibular rotation using the Nault talar dome method were 1.4-3.4 degrees. The distal fibular length had a mean difference between both sides of 0.5-2.1 mm. Although the intraclass correlation's were low, the interleg differences between patients were small, making them useful for clinical practice.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Image Rotation Alters Apparent Fibula Length: An Evaluation of Talocrural Angle, Shenton Line, and Dime Sign

BACKGROUND

Fibula shortening can compromise ankle stability and force transmission, thereby impacting clinical outcomes. Because radiographs depict 3-dimensional anatomy in 2 dimensions, accurate radiographic assessment of fibula length is a commonly encountered clinical challenge. The talocrural angle (TCA), Shenton line, and dime sign are useful parameters of fibula length. Yet, the impact of 3-dimensional limb positioning on these radiographic parameters is not established.

METHODS

Bone models were constructed from CT scans of 30 lower limbs. Fibula length was computationally manipulated, and digitally reconstructed radiographs were generated reflecting 1-degree increments of sagittal and axial plane rotation of each limb for each fibula length condition. The TCA was computationally measured on each image. The presence of an aligned mortise view, intact Shenton line, and intact dime sign was assessed by 2 observers.

RESULTS

The mean TCA, which was 78.0 (95% CI ± 1.6) degrees for a true mortise projection with anatomic fibula length, changed by approximately 1 degree per millimeter of fibula length change. On average, 14.7 degrees of caudal rotation obscured 2 mm of fibular shortening by virtue of producing the same TCA as a true mortise view with anatomic fibula length, designated a false positive view. Axial rotation had a comparatively small effect. Observers 1 and 2 were, respectively, 91% and 88% less likely to accurately judge the image alignment of the false positive images compared to true mortise images. Moreover, intraobserver agreement was poor to moderate (mean 0.47, range 0.13-0.59) and interobserver agreement was uniformly poor (mean 0.08, range 0.01-0.20).

CONCLUSION

In our study using digitally reconstructed radiographs from CT scans of 30 limbs, we found that sagittal plane rotation impacts the radiographic appearance of fibula length as measured by the TCA. Limb axial rotation had a comparatively small effect. Further study of human perception of Shenton line and dime sign is needed before the effect of rotation on these parameters can be fully understood.

LEVEL OF EVIDENCE

Level IV, case series.

Morphological features of the non-affected side of the hindfoot in patients with unilateral varus ankle osteoarthritis

BACKGROUND

The innate shape characteristics of the hindfoot bones alter the loading conditions of the foot and thus may be associated with an increased risk of developing varus ankle osteoarthritis (OA). This study aimed to clarify the innate morphological patterns of the hindfoot bones that may be associated with ankle OA by analyzing the differences between the bone morphology of the non-affected side of patients with unilateral varus ankle OA and that of healthy participants.

METHODS

In this case-control study, computed tomography images were used to develop three-dimensional models of three hindfoot bones (distal tibia with fibula, talus, and calcaneus) from 23 non-affected sides of patients with radiography-diagnosed unilateral ankle OA and 22 healthy control participants. Anatomical and sliding landmarks were placed on the surface of each bone, and the principal components (PCs) of shape variation among specimens were independently calculated for each bone, preserving homology between individuals. The PC modes representing 5% or more of the overall variation were statistically compared between the ankle OA and control groups.

RESULTS

Significant differences were identified between the OA and control groups in the fifth PC mode for the tibia with fibula (proportion of variance, 5.1%; p =.025), fifth PC mode for the talus (6.7%, p =.031), and third PC mode for the calcaneus (7.4%, p =.001). The hindfoot bones of the participants who developed ankle OA had the following innate morphological characteristics: the lateral malleolar articular surface of the fibula was shifted superiorly, tibial plafond was enlarged posteroinferiorly, posterior width of the talar trochlea was narrower, talonavicular articular surface of the talus was oriented more frontally, anterior-middle talocalcaneal articular surfaces of the talus were more medially shifted and those of the calcaneus were flatter, calcaneal sustentaculum tali was less protruding, and lateral plantar process of the calcaneus was more superiorly positioned.

CONCLUSIONS

These distinctive morphological alterations may increase the incidence and progression of varus ankle OA through aberrant anterior translation, internal rotation, and varus tilting of the talus.

Numerical simulations of the effect of lateral malleolus fracture malunion on ankle biomechanics: Different offset directions and offsets

INTRODUCTION

Ankle fractures account for approximately 10 % of all fractures. Approximately 5-68 % of patients with ankle fractures may suffer from malunion. Besides, suboptimal reduction of fracture fragments can affect the biomechanics of the ankle joint, ultimately leading to damage to the ankle joint. However, there are certain controversies over the conclusion of previous cadaveric studies.

METHODS

In this study, a three-dimensional model of the ankle joint was established based on CT image data. In addition, the effects of backward offset (1-2 mm) and outward offset (0.5-1 mm) of the fracture fragment on the contact area, contact pressure, and ligament force of the ankle joint were investigated via the finite element method. Moreover, lateral malleolus fracture malunion in five ankle positions (neutral, 10° dorsiflexion, 10° plantarflexion, 20° dorsiflexion, and 20° plantarflexion) was investigated.

RESULTS

This model predicted an overall increased contact area in the ankle joint in patients with lateral malleolus fracture malunion compared with the normal ankle joint. The results demonstrated that the outward offset had a more significant effect than the backward one. The larger the dorsiflexion-plantarflexion angle, the more pronounced the effect of malunion. Further, an outward offset can cause the fibula to lose its function.

CONCLUSION

Post-traumatic osteoarthritis occurs under the action of unaccustomed cartilage forces due to altered tibial talar joint contact patterns, rather than increased contact pressure reported in previous studies. Malunion leads to an increase or decrease in force on the affected ligament, while the cause of malunion can be envisioned based on a decrease in the force on the ligaments.

Residual Medial Ankle Pain After the Delayed Union of a Lateral Malleolus Fracture: A Case Report

A 17-year-old girl sprained her left ankle and was diagnosed with a lateral malleolar fracture. She was treated conservatively for six months but had medial ankle pain with activity. Imaging revealed an oblique lateral malleolar fracture, with posterolateral displacement and partial fusion of the bone fragments, and bone marrow edema on the medial articular surface of the talus and medial malleolus. We diagnosed ankle instability due to delayed union with a displacement of the lateral malleolus, which caused an osteochondral lesion. We performed arthroscopic and open surgery eight months after the injury, reducted the lateral malleolus anatomically, and fixed it with a plate. Postoperatively, the pain improved rapidly, and the bone marrow edema had almost disappeared on an MRI. In this case, we think rotational instability of the ankle mortise caused abnormal pressure and continuous stress on the medial malleolus after injury, which may have contributed to persistent medial ankle pain.

Role of Lateral Ankle Ligaments in Vertical Stability of the Fibula: A Cadaveric Model

BACKGROUND

In unstable ankle fractures, the role of the deltoid and syndesmosis ligaments has been widely studied. However, it is uncertain what the importance of the lateral ankle ligament complex (LALC) is in the vertical stability of the fibula. Given its anatomical position, it should prevent the proximal translation of the fibula. This study aims to evaluate the role of the LALC in stabilizing the fibula in the vertical plane.

METHODS

Eleven below-knee cadaveric specimens were used in this study. Proximal traction of the fibula was performed by applying 50 N in the intact state and after sequential transection of the syndesmotic ligaments, anterior talofibular ligament (ATFL), and the calcaneofibular ligament (CFL). At each stage, the proximal displacement of the fibula was measured. One-way repeated measures analysis of variance with post hoc Bonferroni correction was carried out to determine any significant differences between the groups. A P value <.05 was considered statistically significant.

RESULTS

The vertical displacement of the fibula in the intact state, and after sequential transection of syndesmotic ligaments, ATFL, and CFL was 1.96 ± 1.19 mm, 3.96 ± 1.33 mm, 5.9 ± 1.73 mm, and 10.22 ± 2.76 mm, respectively. There was no significant difference in the proximal displacement of the fibula between the intact and the syndesmotic ligaments groups (P < .05). However, when the syndesmotic ligaments were transected in conjunction with ATFL ± CFL, a significant difference was observed compared to the intact state (P < .001).

CONCLUSION

The complete disruption of syndesmotic ligaments did not significantly increase the proximal displacement of the fibula. However, when the ATFL ± CFL were additionally disrupted, there was a significant increase in the vertical translation of the fibula.

CLINICAL RELEVANCE

To our knowledge, this is the first study describing that LALC plays a paramount role in the vertical stability of the fibula. Concomitant syndesmosis and LALC should be suspected in an axially unstable fibular fracture with a significant proximal displacement.

Evaluation of Contact Area and Pressure After Malreduction in Isolated Medial Malleolar Fractures With 2 mm of Displacement: A Cadaveric Study

This study was performed to evaluate the changes in contact area and pressure in the tibiotalar joint, with a 2 mm displacement after IMMF (isolated medial malleolar fracture). Ten cadavers with pairs were used to establish a situation in which IMMF occurred during ankle injury. We performed IMMF corresponding to types C and D of the Herscovici classification, and it was displaced by 2 mm. The normal group was defined as a normal tibiotalar joint, the TF (transverse fracture) group as a 2 mm transverse displacement corresponding to the Herscovici classification type C, and the OF (oblique fracture) group as a 2 mm oblique displacement corresponding to the Herscovici classification type D. We measured the contact area and pressure at the tibiotalar joint. The film was scanned and analyzed using the digital imaging software, Scion Image (Scion Crop. Frederick, MD). In normal group, the average contact area of the tibiotalar joint was 317 mm2 (IQR; interquartile range, 256; 347) and 308 mm2 (IQR, 262; 364), average pressure was 2.19 N/mm2 (IQR, 1.94; 2.27) and 2.15 N/mm2 (IQR, 2.06; 2.53). In the TF and OF groups, the average contact area of the tibiotalar joint decreased by 9% and 12%, respectively, and the average pressure increased by 8% and 14%, respectively. There was no statistical difference in peak pressure between the normal, TF, and OF groups. In the case of transverse and oblique fractures, a 2 mm displacement showed significant changes in contact area and contact pressure compared to the normal tibiotalar joint, but there were no significant changes pertaining to type, between the 2 fractures.

Influence of quality of reduction using radiological criteria on kinematics and kinetics in ankle fractures with unstable syndesmotic injury

BACKGROUND

In ankle fractures with syndesmotic injury, the anatomic reduction of the ankle mortise is crucial for preventing osteoarthritis. Yet, no studies have analysed the effect of surgical reduction after unstable ankle fractures on patients' active functional outcome.

METHODS

The Intraoperative 3D imaging data of patients surgically treated between 2012 and 2019 for ankle fracture with concomitant syndesmotic injury were reviewed. 58 patients were allocated to two groups depending on whether the criteria for radiologically optimal reduction were met (39 patients) or not (19 patients). Criteria for optimal reduction were composed of objectively measured and subjectively rated data. After undertaking the Olerud/Molander ankle score, a gait analysis and several active function tests using 3D motion capture were performed in order to evaluate kinetic and kinematic differences between both groups.

FINDINGS

Patients showed deficits of range of motion and balance parameters on the injured ankle, however, there were no significant differences between both groups.

INTERPRETATION

Although, the data did not show that radiological reduction criteria have a statistically significant effect on active functional outcome after a mean follow up time of 5.7 years, tendencies for a better outcome of patients that met the criteria could be seen. It also must be taken into consideration that results are limited by case number and allocation ratio, which made a sub-analysis of the separate reduction criteria unfeasible.

Distal Tibial Metaphyseal Malunion Treated with Clamshell Osteotomy: A Case Report

CASE

Here, we describe a case of a 49-year-old female patient with a history of hypertension and polysubstance use disorder presenting with a distal tibial metaphyseal malunion treated with a clamshell osteotomy. Her follow-up was 2.5 years long.

CONCLUSION

Malunions in the tibial diaphysis and distal metaphysis can cause significantly increased joint reaction forces and altered gait mechanics leading to cosmetic dissatisfaction and decreased quality of life for these patients. Correction of these deformities can improve patient satisfaction and quality of life, along with decrease the risk of early arthritis. The clamshell osteotomy, although initially described to treat diaphyseal long bone malunions, can safely be performed for treatment of complex periarticular metaphyseal malunions.

Biomechanical analysis of different internal fixation methods for special Maisonneuve fracture of the ankle joint based on finite element analysis

OBJECTIVE

The objective of this study was to evaluate the biomechanical properties of different internal fixation methods for Maisonneuve fractures under physiological loading conditions.

METHODS

Finite element analysis was used to numerically analyze various fixation methods. The study focused on high fibular fractures and included six groups of internal fixation: high fibular fracture without fixation + distal tibiofibular elastic fixation (group A), high fibular fracture without fixation + distal tibiofibular strong fixation (group B), high fibular fracture with 7-hole plate internal fixation + distal tibiofibular elastic fixation (group C), high fibular fracture with 7-hole plate internal fixation + distal tibiofibular strong fixation (group D), high fibular fracture with 5-hole plate internal fixation + distal tibiofibular elastic fixation (group E), and high fibular fracture with 5-hole plate internal fixation + distal tibiofibular strong fixation (group F). The finite element method was employed to simulate and analyze the different internal fixation models for the six groups, generating overall structural displacement and Von Mises stress distribution maps during slow walking and external rotation motions.

RESULTS

Group A demonstrated the best ankle stability under slow walking and external rotation, with reduced tibial and fibular stress after fibular fracture fixation. Group D had the least displacement and most stability, while group A had the largest displacement and least stability. Overall, high fibular fracture fixation improved ankle stability. In slow walking, groups D and A had the least and greatest interosseous membrane stress. Comparing 5-hole plate (E/F) and 7-hole plate (C/D) fixation, no significant differences were found in ankle strength or displacement under slow walking or external rotation.

CONCLUSION

Combining internal fixation for high fibular fractures with elastic fixation of the lower tibia and fibula is optimal for orthopedic treatment. It yields superior outcomes compared to no fibular fracture fixation or strong fixation of the lower tibia and fibula, especially during slow walking and external rotation. To minimize nerve damage, a smaller plate is recommended. This study strongly advocates for the clinical use of 5-hole plate internal fixation for high fibular fractures with elastic fixation of the lower tibia and fibula (group E).

The Tibiofibular Line: A Reliable Method of Syndesmosis Assessment in Certain Fibula Morphologies

Background The tibiofibular line (TFL) technique was initially proposed to assess syndesmosis reduction. Clinical utility was limited by low observer reliability when applied to all fibulas. This study aimed to refine this technique by describing TFL's applicability to various fibula morphologies. Methods Three observers reviewed 52 ankle CT scans. Observer consistencies for TFL measurement, anterolateral fibula contact length, and fibula morphology were assessed using intraclass correlation (ICC) and Fleiss' Kappa. Results TFL measurement and fibula contact length intra-observer and inter-observer consistencies were excellent (minimum ICC, 0.87). Fibula shape categorization intra-observer consistency was substantial to almost perfect (Fleiss' Kappa, 0.73 to 0.97). Six to 10 mm of fibula contact length corresponded to excellent TFL distance consistency (ICC, 0.80 to 0.98). Conclusion The TFL technique appears best for patients with 6 mm to 10 mm of straight anterolateral fibula. Sixty-one percent (61%) of fibulas featured this morphology, indicating most patients may be amenable to this technique.

Biomechanical Sequelae of Syndesmosis Injury and Repair

This review characterizes fibula mechanics in the context of syndesmosis injury and repair. Through detailed understanding of fibula kinematics (the study of motion) and kinetics (the study of forces that cause motion), the full complexity of fibula motion can be appreciated. Although the magnitudes of fibula rotation and translation are inherently small, even slight alterations of fibula position or movement can substantially impact force propagation through the ankle and hindfoot joints. Accordingly, implications for clinical care are discussed.

Multi-Body 3D-2D Registration for Robot-Assisted Joint Reduction: Preclinical Evaluation in the Ankle Syndesmosis

Purpose

Existing methods to improve the accuracy of tibiofibular joint reduction present workflow challenges, high radiation exposure, and a lack of accuracy and precision, leading to poor surgical outcomes. To address these limitations, we propose a method to perform robot-assisted joint reduction using intraoperative imaging to align the dislocated fibula to a target pose relative to the tibia.

Methods

The approach (1) localizes the robot via 3D-2D registration of a custom plate adapter attached to its end effector, (2) localizes the tibia and fibula using multi-body 3D-2D registration, and (3) drives the robot to reduce the dislocated fibula according to the target plan. The custom robot adapter was designed to interface directly with the fibular plate while presenting radiographic features to aid registration. Registration accuracy was evaluated on a cadaveric ankle specimen, and the feasibility of robotic guidance was assessed by manipulating a dislocated fibula in a cadaver ankle.

Results

Using standard AP and mortise radiographic views registration errors were measured to be less than 1 mm and 1° for the robot adapter and the ankle bones. Experiments in a cadaveric specimen revealed up to 4 mm deviations from the intended path, which was reduced to <2 mm using corrective actions guided by intraoperative imaging and 3D-2D registration.

Conclusions

Preclinical studies suggest that significant robot flex and tibial motion occur during fibula manipulation, motivating the use of the proposed method to dynamically correct the robot trajectory. Accurate robot registration was achieved via the use of fiducials embedded within the custom design. Future work will evaluate the approach on a custom radiolucent robot design currently under construction and verify the solution on additional cadaveric specimens.

Acute Syndesmosis Injuries

Ankle syndesmosis injuries include isolated ligamentous rupture, as well as fractures with ligamentous injury. These injuries can significantly affect athletes in all sports, and lead to prolonged recovery and return to sport. Adequate evaluation and diagnosis of these injuries are imperative for treatment and return to play. Many can be treated nonoperatively, but operative treatment is indicated in fractures with syndesmosis disruption and ligamentous injuries with instability. Anatomic reduction and fixation of these injuries will allow functional rehab and return to sport.

Restoration of Anatomic Parameters and Syndesmotic Reduction After Intramedullary Nailing of Distal Fibular Fractures

Background:

Intramedullary nailing of the fibula (FN) is a method of fixation that has proven to be useful for treating distal fibular fractures (DFs). FN minimizes soft tissue complications and provides similar stability to plating, with fewer hardware-related symptoms. Nevertheless, FN has been associated with syndesmotic malreduction and the incapacity of restoring length and rotation of the fibula. We aimed to evaluate the fibular position and syndesmotic reduction after fixation with FN compared with the uninjured ankle in the immediate postoperative period.

Methods:

Prospective cohort study. Patients with DF fractures treated with IN between January 2017 and January 2020 were included. Immediate postoperative bilateral ankle CT was obtained in all cases. Fibular rotation, length, and translation as well as syndesmotic diastasis were measured on both ankles and compared by 3 independent observers.

Results:

Twenty-eight patients were included (16 women). The mean age was 46 years (range 16-91). Fracture type distribution according to AO/ASIF classification included 19 patients with 44.B (67.9%), 8 patients with 44.C (28.6%), and 1 patient with a 44.A fracture (3.6%). No significant differences were identified considering fibular rotation (P = .661), syndesmotic diastasis (P = .147), and fibular length (P = .115) between the injured and uninjured ankle. Fibular translation had statistical differences (P = .01) compared with the uninjured ankle. The intraclass correlation coefficient showed an excellent concordance between observers except for fibular translation on the injured ankle.

Conclusion:

In this cohort, fixation of DF fractures with FN allows restoration of anatomical parameters of the ankle in terms of fibular rotation, length, and syndesmotic diastasis. However, fibular translation had significant differences compared with the uninjured ankle based on bilateral CT scan evaluation.

Level of Evidence:

Level II, prospective cohort study.

Measuring Deltoid Insufficiency After Supination-External Rotation Ankle Fracture With Lateral Talar Subluxation on Gravity Stress View

BACKGROUND

Stress-view radiographs are frequently obtained to evaluate supination-external rotation (SER) variant ankle fractures. Measurement of the ankle medial clear space (MCS) is a surrogate of medial structure integrity as part of overall ankle stability. Measurement of the lateral talus displacement with respect to the incisura may be a sensitive and specific method to assess joint subluxation.

METHODS

Retrospective review of acute SER-variant isolated lateral malleolar fractures with gravity stress views (GSVs) were performed for 103 patients. GSV analysis was performed with standardized measurements of the MCS, superior clear space (SCS), and 2 new novel measurements of lateral talus subluxation (LTS). Decision for surgery was obtained by surgeons who reviewed masked injury radiographs for predictive performance analysis of the LTS vs MCS.

RESULTS

MCS, SCS, and LTS measurements were performed on 103 patients. Mean MCS, SCS, and LTS within the operative group was increased. MCS ≥5 mm and LTS >4 mm had equal sensitivity (95%), with higher specificity for LTS (75% vs 60%). Receiver operating characteristic analysis demonstrates an area under the curve of 0.786 for MCS ≥5 mm vs 0.918 for LTS >4 mm.

CONCLUSION

We found LTS to be superior to MCS for medial ankle structure stability on gravity stress views of SER-variant ankle fractures. We propose this as a useful tool for clinicians to consider when evaluating SER-variant ankle fractures.

LEVEL OF EVIDENCE

Level II, prospective comparative study of radiographs.

Is the osteosynthesis of lateral malleolar fractures by pin/cerclage effective? A retrospective study

INTRODUCTION

Lateral malleolar fractures are present in about 90% of ankle fractures. The standard treatment is plate osteosynthesis. Although the plates are thin, the risk of cicatricial complications is not insignificant and can lead to cutaneous or even infectious complications and the latter can cause functional repercussions. We therefore aimed to evaluate a technique consisting of osteosynthesis of the lateral malleolus using two cerclages and two intramedullary pins.

HYPOTHESIS

Our hypothesis is that the use of osteosynthesis by pin/cerclage of the lateral malleolus makes it possible to have objective reduction criteria, similar to the reference treatment.

METHODS

This is a retrospective study of patients who had an interligamentous spiral fracture of the lateral malleolus. One group of patients had internal fixation of the lateral malleolus fracture by pins, and the other by plate. Our primary outcome was to compare the reduction of the fracture of the lateral malleolus between the two techniques using the "Dime sign", the measurement of the talocrural angle and respect for Shenton's line.

RESULTS

A total of 118 lateral malleolar fractures were included: 56 patients (47.5%) in the "pin" group and 62 patients (52.5%) in the "plate" group. The mean age of the patients was 46.6 years (17.4) with an average body mass index of 25.2kg/m² (4.8) and 55.1% of the patients were women. We found a difference in the reduction criteria between the two groups by looking at Shenton's line: 73.2% (41/56) of postoperative X-rays in the "pin" group respected Shenton's line, compared to 90.3% (56/62) in the "plate" group (p=0.02). We did not find any difference regarding the "Dime sign" and the talocrural angle.

CONCLUSION

Our study shows the superiority of plate osteosynthesis for lateral malleolar fractures compared to pin/cerclage osteosynthesis, regarding one of the three radiological criteria for reduction. No significant difference was found in the one-year rates of complications and of hardware removal, between the two groups.

LEVEL OF EVIDENCE

IV, retrospective study.

Detection of fibular rotational changes in cone beam CT: experimental study in a specimen model

Background

In syndesmotic injuries, incorrect reduction leads to early arthrosis of the ankle joint. Being able to analyze the reduction result is therefore crucial for obtaining an anatomical reduction. Several studies that assess fibular rotation in the incisura have already been published. The aim of the study was to validate measurement methods that use cone beam computed tomography imaging to detect rotational malpositions of the fibula in a standardized specimen model.

Methods

An artificial Maisonneuve injury was created on 16 pairs of fresh-frozen lower legs. Using a stable instrument, rotational malpositions of 5, 10, and 15° internal and external rotation were generated. For each malposition of the fibula, a cone beam computed tomography scan was performed. Subsequently, the malpositions were measured and statistically evaluated with t-tests using two measuring methods: angle (γ) at 10 mm proximal to the tibial joint line and the angle (δ) at 6 mm distal to the talar joint line.

Results

Rotational malpositions of ≥ 10° could be reliably displayed in the 3D images using the measuring method with angle δ. For angle γ significant results could only be displayed for an external rotation malposition of 15°.

Conclusions

Clinically relevant rotational malpositions of the fibula in comparison with an uninjured contralateral side can be reliably detected using intraoperative 3D imaging with a C-arm cone beam computed tomography. This may allow surgeons to achieve better reduction of fibular malpositions in the incisura tibiofibularis.

Treatment and outcome of a patient with low-energy 'Logsplitter' injury

The low-energy ‘Logsplitter’ fracture, caused by a sprain or fall, is characterized by an intact or slightly separated inferior tibiofibular joint. Compared with the high-energy ‘Logsplitter’ fracture, this atypical subtype is rarely seen and is easily missed. Here, the case of a 33-year-old male patient with a fractured right ankle as a result of a sprain during walking is reported. The patient initially received routine surgical treatment comprising internal fixation of the fibular, medial and posterior malleoli. Unexpectedly, post-surgery imaging examinations revealed that the medial clear space of the right ankle had widened to 6 mm, due to incomplete reduction of the lateral malleolus, shortening and rotation of the fibula, and an unreduced avulsion fracture block of the anterior malleolus. A revision surgery was then performed to anatomically reduce and fix the lateral malleolus, as well as the anterior malleolus avulsion fracture. During 5 months following surgery, the patient achieved good fracture union and functional restoration of the right ankle. For this rare injury, the present case demonstrates that complete restoration of the fracture is required to achieve good clinical efficacy.

Radiographic Assessment of Ankle Fracture Displacement: A Validation Study

BACKGROUND

Ankle fracture displacement is an important outcome in clinical research examining the effectiveness of surgical and rehabilitation interventions. However, the assessment of displacement remains subjective without well-described or validated measurement methods. The aim of this study was to assess inter- and intrarater reliability of ankle fracture displacement radiographic measures and select measurement thresholds that differentiate displaced and acceptably reduced fractures.

METHODS

Eight fellowship-trained orthopaedic surgeons evaluated a set of 26 postoperative ankle fracture radiographs on 2 occasions. Surgeons followed standardized instructions for making 5 measurements: coronal displacement (3) talar tilt (1), and sagittal displacement (1). Inter- and intraobserver interclass correlations were determined by random effects regression models. Logistic regression was used to determine the optimal sensitivity and specificity for the measurements with the highest correlation.

RESULTS

Three of the 5 measures had excellent interobserver reliability (correlation coefficient &gt; 0.75): (1) coronal plane distance between the lateral border of tibia and lateral border of talus, (2) coronal plane talar tilt, and (3) sagittal plane displacement. The threshold that best discriminated displaced from well-aligned fractures was 2 mm for coronal plane distance (sensitivity 82.1%, specificity 85.4%), 3 degrees for talar tilt (sensitivity 80.4%, specificity 82.2%), and 5 mm for sagittal plane distance (sensitivity 83.9%, specificity 84.9%).

CONCLUSION

This study identified 3 reliable measures of ankle fracture displacement and determined optimal thresholds for discriminating between displaced and acceptably reduced fractures. These measurement criteria can be used for the design and conduct of clinical research studying the impact of surgical treatment and rehabilitation interventions.

Quantification of manipulation forces needed for robot-assisted reduction of the ankle syndesmosis: an initial cadaveric study

PURPOSE

Manual surgical manipulation of the tibia and fibula is necessary to properly align and reduce the space in ankle fractures involving sprain of the distal tibiofibular syndesmosis. However, manual reduction is highly variable and can result in malreduction in about half of the cases. Therefore, we are developing an image-guided robotic assistant to improve reduction accuracy. The purpose of this study is to quantify the forces associated with reduction of the ankle syndesmosis to define the requirements for our robot design.

METHODS

Using a cadaveric specimen, we designed a fixture jig to fix the tibia securely on the operating table. We also designed a custom fibula grasping plate to which a force-torque measuring device is attached. The surgeon manually reduced the fibula utilizing this construct while translational and rotational forces along with displacement were being measured. This was first performed on an intact ankle without ligament injury and after the syndesmosis ligaments were cut.

RESULTS

Six manipulation techniques were performed on the three principal directions of reduction at the cadaveric ankle. The results demonstrated the maximum force applied to the lateral direction to be 96.0 N with maximum displacement of 8.5 mm, applied to the anterior-posterior direction to be 71.6 N with maximum displacement of 10.7 mm, and the maximum torque applied to external-internal rotation to be 2.5 Nm with maximum rotation of 24.6°.

CONCLUSIONS

The specific forces needed to perform the distal tibiofibular syndesmosis manipulation are not well understood. This study quantified these manipulation forces needed along with their displacement for accurate reduction of ankle syndesmosis. This is a necessary first step to help us define the design requirements of our robotic assistance from the aspects of forces and displacements.

Ankle Joint Pressure in Supination-External Rotation Injuries: A Biomechanical Study in an Unrestrained Cadaver Model

BACKGROUND

Previous biomechanical studies simulating supination-external rotation (SER) IV injuries revealed different alterations in contact area and peak pressure. We investigated joint reaction forces and radiographic parameters in an unrestrained, more physiological setup.

METHODS

Twelve lower leg specimens were destabilized stepwise by osteotomy of the fibula (SER II) and transection of the superficial (SER IVa) and the deep deltoid ligament (SER IVb) according to the Lauge-Hansen classification. Sensors in the ankle joint recorded tibio-talar pressure changes with axial loading at 700 N in neutral position, 10° of dorsiflexion, and 20° of plantarflexion. Radiographs were taken for each step.

RESULTS

Three of 12 specimen collapsed during SER IVb. In the neutral position, the peak pressure and contact area changed insignificantly from 2.6 ± 0.5 mPa (baseline) to 3.0 ± 1.4 mPa (SER IVb) (P = .35) and from 810 ± 42 mm² to 735 ± 27 mm² (P = .08), respectively. The corresponding medial clear space (MCS) increased significantly from 2.5 ± 0.4 mm (baseline) to 3.9 ± 1.1 mm (SER IVb) (P = .028).The position of the ankle joint had a decisive effect on contact area (P = .00), center of force (P = .00) and MCS (P = .01).

CONCLUSION

Simulated SER IVb injuries demonstrated radiological, but no biomechanical changes. This should be considered for surgical decision making based on MCS width on weightbearing radiographs.

LEVELS OF EVIDENCE

Not applicable. Biomechanical study.

Effect of weightbearing and foot positioning on 3D distal tibiofibular joint parameters

The aim of this study was to investigate the effect of different loading scenarios and foot positions on the configuration of the distal tibiofibular joint (DTFJ). Fourteen paired human cadaveric lower legs were mounted in a loading frame. Computed tomography scans were obtained in unloaded state (75 N) and single-leg loaded stand (700 N) of each specimen in five foot positions: neutral, 15° external rotation, 15° internal rotation, 20° dorsiflexion, and 20° plantarflexion. An automated three-dimensional measurement protocol was used to assess clear space (diastasis), translational angle (rotation), and vertical offset (fibular shortening) in each foot position and loading condition. Foot positioning had a significant effect on DTFJ configuration. Largest effects were related to clear space increase by 0.46 mm (SD 0.21 mm) in loaded dorsal flexion and translation angle of 2.36° (SD 1.03°) in loaded external rotation, both versus loaded neutral position. Loading had no effect on clear space and vertical offset in any position. Translation angle was significantly influenced under loading by - 0.81° (SD 0.69°) in internal rotation only. Foot positioning noticeably influences the measurements when evaluating DTFJ configuration. Loading seems to have no relevant effect on native ankles in neutral position.

A Quantitative Method for Intraoperative Evaluation of Distal Fibular Malrotation

Background

Due to the low sensitivity of commonly used radiographic parameters for the evaluation of rotational malreduction of the distal fibula under intraoperative fluoroscopy, a quantitative method is needed to make up for this defect.

Methods

A total of 96 sets of computed tomography images of normal ankles were imported into MIMICS to reconstruct 3D models. The fibula models were rotated along the longitudinal axis from 30 degrees of external rotation to 30 degrees of internal rotation. Virtual X-ray function in MIMICS was used to obtain radiographic images in mortise view. A line was drawn through the tip of the medial malleolus and parallel to the distal tibial plafond, the distances from the medial edge of the fibula to the lateral malleolar fossa cortex and from the medial edge of the fibula to the lateral edge of the fibula were measured on this line, and the ratio of them was calculated and marked as ratio α.

Results

The mean ratio α for normal ankles was 0.49 ± 0.06, while the 95% confidence interval was 0.48–0.50. The ratio α decreased when the fibula was externally rotated and increased when the fibula was internally rotated. The effects of different genders or different types on each group of data were compared, and the p values were all greater than 0.05.

Conclusions

This is a new method to quantitatively evaluate rotational malreduction of the distal fibula during operation. The ratio α can correspond to the rotation angle of the fibula. The larger the ratio α, the more the internal rotation of the fibula. Contrarily, the smaller the ratio α, the more the external rotation of the fibula. Making the ratio α close to 0.5 may be an intuitive approach that can be used intraoperatively.

Correction of the Valgus Ankle with a Joint Sparing Supra-Malleolar Osteotomy: The Modified Wiltse Technique

The valgus ankle is a common cause of pain, deformity, and disability in patients. Addressing these deformities with extraarticular osteotomies is a valuable, joint-sparing treatment option. The modified Wiltse osteotomy provides correction of the mechanical alignment as well as allowing inherent stability. Accurate templating of the Wiltse triangle enables reproducible, accurate intraoperative results.

Risk Factors for Aseptic Revision of Operatively Treated Ankle Fractures

BACKGROUND

Early revision rates within 12 months after ankle fracture open reduction internal fixation (AF-ORIF) are fairly low; however, they remain relevant given the volume of ankle fractures occurring annually. Understanding these rates is complex because reoperation due to technical or mechanical complications is typically reported alongside soft tissue-related problems such as symptomatic hardware, wound dehiscence, or infection. There are limited data identifying risk factors specifically for revision of ankle fracture fixation in the absence of soft tissue complications. Understanding variables that predispose to aseptic technical and mechanical failure without this confounder may provide insight and improve patient care.

METHODS

A retrospective cohort study was performed at 2 large academic medical centers. Research Patient Data Registry (RPDR) data available from 2002 to 2019 were used to identify patients who underwent aseptic revision of AF-ORIF within 12 months (n = 33). A control group (n = 100) was selected by identifying sequential patients who underwent AF-ORIF not requiring revision within 12 months. Multiple factors were recorded for all patients in both cohorts. Each fracture was also evaluated according to the Ankle Reduction Classification System (ARCS) of Chien et al,⁸ which categorizes biplanar talar displacement in relation to a central tibial plumb line into 1 of 3 grades: A (0-2 mm), B (3-10 mm), and C (>10 mm). Adapted from its original purpose of grading reduction quality, we applied ARCS to pre-reduction radiographs to assess initial fracture displacement. All variables collected were compared in univariate analysis. Variables that achieved significance in univariate comparisons were included as candidates for multivariable analysis.

RESULTS

Final multivariable logistic regression modeling demonstrated the following factors to independently predict the need for aseptic revision surgery: documented falls in the early postoperative period (aOR, 298; 95% CI, 15.4, 5759; P < .001), movement-altering disorders (aOR, 81.7; 95% CI, 4.12, 1620; P = .004), a nonanatomic mortise (medial clear space [MCS] > superior clear space [SCS]) on immediate postoperative imaging (aOR, 38.4; 95% CI, 5.53, 267; P < .001), initial coronal plane tibiotalar displacement >10 mm and sagittal plane tibiotalar dislocation (ARCS-C) (aOR vs ARCS-A, 25.8; 95% CI, 2.81, 237; P = .004), substance abuse (aOR, 15.7; 95% CI, 2.66, 92.8; P = .002), and polytrauma (aOR, 12.3; 95% CI, 2.02, 74.8; P = .006).

CONCLUSION

In this investigation we found a notable increase in risk for revision surgery after AF-ORIF for patients who had one of the following: (1) falls in the early postoperative period, (2) movement-altering disorders, (3) a nonanatomic mortise (MCS > SCS) on immediate postoperative imaging, (4) more severe initial fracture displacement, (5) substance abuse, or (6) polytrauma. Identifying these factors may allow surgeons to better understand risk and counsel patients, and may serve as future targets for intervention aimed at improving patient safety and outcomes after ankle fracture ORIF.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Long-Term Follow-up of Functional and Radiographic Outcome After Revision Surgery for Fibula Malunion

Background. Ankle fractures are some of the most common injuries seen in the emergency department. Malunited ankle fractures are uncommon. Patients with malunion frequently present with multiple complaints. Radiographs often show abnormalities in anatomical alignment. Aim. To evaluate the anatomical alignment on radiographic imaging in patients with malunited ankle fractures. Secondary aims were to evaluate patient satisfaction after reconstruction and to investigate the relationships between radiological alignment and functional outcome. Methods. All consecutive patients (n = 25) treated for a fibula malunion between January 1, 2002, and September 1, 2017, were included. The primary outcome was anatomical alignment of the ankle mortise. The talocrural angle (TCA), talar tilt (TT), and medial clear space (MCS) were used to investigate to what extent revision surgery had improved alignment. The patient-related outcome measure consisted of the Olerud and Molander Ankle Score (OMAS). To assess quality of life (QoL) the EQ-5D-5L was used. Results. The median TCA was 78.4° before revision and 79.25° after revision; P = .297. The median TT was 2.95° before revision and 0.70° after; P < .001. The MCS before revision was 5.2 mm and 3.17 mm after; P < .000). The OMAS had a median of 67.5 points. Analysis of the QoL questionnaires yielded a score of 0.84 points. Conclusion. Anatomical alignment improves significantly after revision surgery of malunited ankles. Measurements of the TCA appeared less useful in determining the anatomical alignment. In our series, 60% of patients reported good to excellent results. The QoL scores of our patient were comparable to those in the healthy population in the Netherlands.Levels of Evidence: Level IV: Case series.

Utility of WBCT to Diagnose Syndesmotic Instability in Patients With Weber B Lateral Malleolar Fractures

BACKGROUND

Diagnosing syndesmotic instability accompanying Weber B ankle fractures can be challenging. This study aimed to evaluate the ability of weight-bearing computed tomography (WBCT) to diagnose syndesmotic instability using one-dimensional, two-dimensional, and three-dimensional measurements among patients with unilateral Weber B lateral malleolar fractures with symmetric medial clear space (MCS) on initial radiographs and yet demonstrated operatively confirmed syndesmotic instability.

METHODS

The treatment group included 23 patients with unilateral surgically confirmed syndesmotic instability accompanying Weber B ankle fractures who underwent preoperative bilateral foot and ankle WBCT. The control group included 18 unilateral Weber B ankle fracture patients without syndesmotic instability who underwent bilateral WBCT. Measurements on WBCT images included the following: (1) syndesmotic area, (2) anterior, middle, and posterior distal tibiofibular distance, (3) fibular rotation, (4) distance from fibular tip to plafond, (5) fibular fracture displacement, and (6) MCS distance. In addition, the following volumetric measurements were calculated: (1) syndesmotic joint volume from the tibial plafond extending to 3 and 5 cm proximally, (2) MCS volume, and (3) lateral clear space volume. Area under the receiver operating characteristic curve analysis and Delong test were used, and optimal cutoff values to distinguish between stable and unstable syndesmosis were determined using Youden J statistic.

RESULTS

Among patients with unilateral syndesmotic instability and Weber B ankle fractures, all WBCT measurements were significantly greater than uninjured side, except MCS distance, syndesmotic area, and anterior and posterior tibiofibular distances (P values <0.001 to 0.004). Moreover, syndesmosis volume spanning from the tibial plafond to 5 cm proximally had the largest area under the curve of 0.96 (sensitivity = 90%; specificity = 95%), followed by syndesmosis volume up to 3 cm proximally (area under the curve = 0.91; sensitivity = 90%; specificity = 90%). Except for MCS volume and distal fibular tip to tibial plafond distance, the control group showed no side-to-side difference in any parameter.

CONCLUSION

Syndesmotic joint volume measurements seem to be best suited to diagnose syndesmotic instability among patients with Weber B ankle fractures, compared with other two-dimensional and three-dimensional WBCT measurements.

LEVEL OF EVIDENCE

Level III, comparative diagnostic study.

Ankle fractures involving the posterior malleolus: patient characteristics and 7-year results in 100 cases

INTRODUCTION

The presence of a posterior malleolar (PM) fragment has a negative prognostic impact in ankle fractures. The best treatment is still subject to debate. The aim of this study was to assess the medium-to-long-term clinical and functional outcome of ankle fractures with a PM fragment in a larger patient population.

MATERIALS AND METHODS

One hundred patients (69 women, 31 men, average age 60 years) with ankle fractures including the PM were evaluated clinically and radiographically. Patients with Bartoníček-Rammelt type 3 and 4 fracture displayed a significant female preponderance. Fixation of the PM was performed in 63% and tailored to the individual fracture pattern.

RESULTS

Internal fixation of the PM fragment was negatively correlated with the need for syndesmotic screw placement at the time of surgery (p = 0.010). At an average follow-up of 7.0 years, the mean Foot Function Index (FFI) was 16.5 (SD: 21.5), the Olerud Molander Ankle Score (OMAS) averaged 80.2 (SD: 24) and the American Orthopedic Foot & Ankle Society (AOFAS) ankle/hindfoot score averaged 87.5 (SD: 19.1). The maximum score of 100 was achieved by 44% of patients. The physical (PCS) and mental health component summary (MCS) scores of the SF-36 averaged 47.7 (SD: 12.51) and 50.5 (SD: 9.36), respectively. Range of motion was within 3.4 (SD: 6.63) degrees of the uninjured side. The size of the PM fragment had no prognostic value. There was a trend to lower outcome scores with slight anterior or posterior shift of the distal fibula within the tibial incisura. Patients who underwent primary internal fixation had significantly superior SF-36 MCS than patients who underwent staged internal fixation (p = 0.031).

CONCLUSIONS

With an individualized treatment protocol, tailored to the CT-based assessment of PM fractures, favorable medium and long-term results can be expected.

Does the orientation of syndesmosis fixative device affect the immediate reduction of the distal tibiofibular joint?

INTRODUCTION

Incongruent stabilization of the distal tibiofibular joint (syndesmosis) results in poorer long-term outcome in malleolar fractures. The aim was to analyze whether the orientation of the syndesmotic stabilization would affect the immediate reduction imaged in computed tomography (CT).

MATERIALS AND METHODS

The syndesmotic congruity in 114 ankle fractures with stabilization of the syndesmosis were retrospectively analyzed in the post-operative bilateral CT scans. The incisura device angle (IDA) was defined and correlated with the side-to-side difference of Leporjärvi clear-space (ΔLCS), anterior tibiofibular distance (ΔantTFD) and Nault talar dome angle (ΔNTDA) regardless of the stabilization technique and separately for suture button system and syndesmotic screw. Asymmetric reduction was defined as ΔLCS > 2 mm and |ΔantTFD|> 2 mm.

RESULTS

Regardless of the stabilization technique, no correlation between the IDA and the ΔLCS (r = 0.069), the ΔantTFD (r = 0.019) nor the ΔNTDA (r = 0.177) could be observed. There were no differences between suture button system and syndesmotic screw. Asymmetrical reduction was detected in 46% of the cases, while sagittal asymmetry was most common. No association was found between the orientation of stabilization device and occurrence of asymmetrical reduction (p > 0.05). The results of suture button system and syndesmotic screw were comparable in this respect (p > 0.05).

CONCLUSION

Poor correlation between the orientation of the stabilization device and the immediate post-operative congruity of the syndesmosis could be shown. In contrast to current literature, this study did not show difference of suture button system over syndesmotic screw in this regard. Careful adjustment of the fibula in anteroposterior orientation should be given special attention.

Suture button versus syndesmotic screw in ankle fractures - evaluation with 3D imaging-based measurements

BACKGROUND

Inadequate reduction of syndesmotic injuries can result in disabling clinical outcomes. The aim of the study was to compare syndesmosis congruity after fixation by syndesmotic screws (SYS) or a suture button system (SBS) using three-dimensional (3D) computed imaging techniques.

METHODS

In a retrospective single-center study, patients with unilateral stabilization of an ankle fracture with a syndesmotic injury and post-operative bilateral CT scans were analyzed using a recently established 3D method. The side-to-side differences were compared for tibio-fibular clear space (∆CS), translation angle (∆α), and vertical offset (∆z) among patients stabilized with syndesmotic screws or suture button system. Syndesmotic malreduction was defined for ∆CS > 2 mm and for |∆α| > 5°. ∆CS and ∆α were correlated with two-dimensional (2D) measurements.

RESULTS

Eighteen patients stabilized with a syndesmosis screw and 29 stabilized with a suture button system were analyzed. After stabilization, both groups revealed mild diastasis (SYS: mean ∆CS 0.3 mm, SD 1.1 mm vs SBS: mean ∆CS 0.2 mm, SD 1.2 mm, p = 0.710). In addition, both stabilization methods showed slight dorsalization of the fibula (SYS: mean ∆α 0.5°, SD 4.6° vs SBS: mean ∆α 2.1°, SD 3.7°, p = 0.192). Also, restoration of the fibula-to-tibia length ratio also did not differ between the two groups (SYS: mean Δz of 0.5 mm, SD 2.4 mm vs SBS: mean Δz of 0 mm, SD 1.2 mm; p = 0.477). Malreduction according to high ∆α was most common (26% of cases), with equal distribution between the groups (p = 0.234). ∆CS and ∆α showed good correlation with 2D measurements (ρ = 0.567; ρ = 0.671).

CONCLUSION

This in vivo analysis of post-operative 3D models showed no differences in immediate post-operative alignment after syndesmotic screws or suture button system. Special attention should be paid to syndesmotic malreduction in the sagittal orientation of the fibula in relation to the tibia in radiological control of the syndesmotic congruity as well as intra-operatively.

Ankle CT scan allows better management of posterior malleolus fractures than X-rays

PURPOSE

Undiagnosed and undertreated posterior malleolus fractures lead to early ankle instability and arthritis. A preoperative CT scan could improve the management of those fractures. This study assessed the benefits of a systematic ankle CT scanner to diagnose and manage posterior malleolus fracture.

METHODS

A monocentric retrospective cohort study was conducted. Sixty consecutive patients with bimalleolar fractures were operated and underwent a preoperative CT scan. The mean age was 50.0 years old (18.6 years old) with a mean body mass index of 20.3 (kg/m²) (11.4 kg/m²) and 71.7% (43/60) of women. The primary outcome was the rate of posterior malleolus fragment diagnosed on X-rays and on CT scan. Secondly, interobserver and interobserver's agreement were compared between conventional X-rays and CT scan.

RESULTS

Thirty-five (58.3%) posterior fragment fractures were observed on X-rays and 53 (88.3%) on the preoperative CT scan (p < 0.01). The intraobserver reproducibility for X-rays was low (0.02 [- 0.23; 0.27]) and moderate for CT scan (0.45 [0.0; 0.84]). The interobserver reproducibility for X-rays was moderate (0.39 [0.15; 0.60]) and excellent for CT scan (0.78 [0.0; 1.0]).

CONCLUSION

A wide proportion of bimalleolar fractures are associated with posterior malleolus fractures and undiagnosed with standard X-rays. We advocate a systematic preoperative CT scan in the management of bimalleolar fractures.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

TRIAL REGISTRATION NUMBER

2218999v0, date of registration: 11/08/2020 (retrospectively registered).

Follow-up Evaluation of Medial Clear Space and Talar Tilt After Bimalleolar Equivalent Fracture Fixation Without Primary Deltoid Repair

BACKGROUND

We sought first to determine the efficacy of lateral ankle fixation alone in maintenance of medial clear space and talar valgus in bimalleolar equivalent ankle fractures not receiving primary deltoid repair, and second to assess perceived outcomes via the Foot and Ankle Outcome Score. To our knowledge, no study has quantified the reduction of medial clear space and talar valgus in bimalleolar equivalent ankle fractures receiving lateral ankle fixation alone.

METHODS

We compared preoperative, initial postoperative, and greater than 1-year follow-up radiographs of medial clear space and talar valgus in individuals who received lateral ankle fixation alone in bimalleolar equivalent ankle fractures. Subjective outcomes were measured via the Foot and Ankle Outcome Score.

RESULTS

Thirty-seven patients participated in the study and showed a statistically significant reduction of medial clear space and restoration of talar position, and maintenance with this fixation method during follow-up in patients with bimalleolar equivalent ankle fractures. Adjunctively, patients perceived their outcomes to be satisfactory, as demonstrated by the results of the Foot and Ankle Outcome Score.

CONCLUSIONS

We aimed to assess the efficacy of lateral ankle fixation in the maintenance of medial clear space and talar valgus reduction at midterm follow-up. Although some authors contend that primary deltoid repair in bimalleolar equivalent ankle fractures is warranted, these midterm study results suggest that isolated lateral ankle fixation is adequate for medial ankle stabilization in bimalleolar equivalent fractures, and thus primary deltoid repair is not indicated.