Medial Clear Space Widening Research Articles

EFFECT OF FIBULA SHORTENING ON MEDIAL CLEAR SPACE AND LATERAL TRANSLATION OF THE TALUS: AN ANATOMICAL CADAVERIC STUDY

IntroductionFibula shortening with an intact anterior tibiofibular ligament (ATFL) and medial ligament instability causes lateral translation of the talus. Our hypothesis was that the interaction of the AITFL tubercle of the fibular with the tibial incisura would propagate lateral translation due to the size differential.AimTo assess what degree of shortening of the fibular would cause the lateral translation of the talus.MethodologyTwelve cadaveric ankle specimens were dissected removing all soft tissue except for ligaments. They were fixed on a specially-designed platform within an augmented ankle cage allowing tibial fixation and free movement of the talus. The fibula was progressively shortened in 5mm increments until complete ankle dislocation. The medial clear space was measured with each increment of shortening.ResultsThe larger AITFL tubercle interaction with the smaller tibial incisura caused a significant increase in lateral translation of the talus. This occurred in most ankles between 5–10mm of fibular shortening. The medial clear space widened following 5mm of shortening in 5 specimens (mean=2.0725, SD=±2.5338). All 12 specimens experienced widening by 10mm fibula shortening (Mean=7.2133mm, SD=±2.2061). All specimens reached complete dislocation by 35mm fibula shortening. Results of ANOVA analysis found the data statistically significant (p<0.0001).ConclusionThis study shows that shortening of the fibula causes a significant lateral translation of the talus provided the ATFL remains intact. Furthermore, the interaction of the fibula notch with the ATFL tubercle of the tibia appears to cause a disproportionate widening of the medial clear space due to its differential in size. Knowledge of the extent of fibula shortening can guide further intervention when presented with a patient experiencing medial clear space widening following treatment of an ankle fracture.

Successful Outcomes with Nonoperative Treatment and Immediate Weightbearing Despite Stress-Positive Radiographs in Isolated Distal Fibula (OTA/AO 44B) Fractures.

Objectives: To determine if a nonoperative management protocol results in equivalent outcomes in isolated OTA/AO 44B (Weber B) fractures without initial medial clear space (MCS) widening regardless of stress radiography findingsDesign: Prospective cohortSetting: Level 1 academic trauma centerPatients/Participants: Sixty-nine patients with isolated OTA/AO 44B fractures and MCS ≤ 4 mm on initial non-weightbearing injury radiographs over a 4-year periodIntervention: nonoperative management of isolated OTA/AO 44B fractures without initial MCS widening > 4 mmMain Outcome Measurements: MCS measurements on weightbearing radiographs at first follow up, six weeks, 12 weeks, and six months post-injury; American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scoresResults: None of the 38/69 (55%) patients with widening on gravity stress radiographs demonstrated persistent widening with weightbearing radiographs at any time point. Mean MCS measurement differences between the two cohorts were statistically significant for all time points (p=0.012), however with a model adjusted mean MCS value of 2.7 mm for the non-widening cohort and 2.9 mm for the widening cohort, these are not clinically significant. There was no statistically significant difference in overall final AOFAS scores between the two groups (p=0.451). Additionally, statistical equivalence using Schuirmann's two one-sided tests was achieved between the two groups. Both cohorts had mean AOFAS scores representing excellent outcomes at final follow up.Conclusions: Isolated OTA/AO 44B fractures without MCS widening on initial injury radiographs have equivalent outcomes regardless of gravity stress radiography findings when treated nonoperatively. Weightbearing radiographs at initial follow-up are a reliable assessment of ankle stability in these injuries and are an appropriate alternative to painful and time-consuming stress radiography.Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Effect of Fibula Shortening on Medial Clear Space and Lateral Translation of the Talus: An Anatomical Cadaveric Study

Category: Ankle; Trauma Introduction/Purpose: Fibular shortening with an medial and syndesmotic ligament instability causes lateral translation of the talus. We hypothesise that the interaction of the anterior inferior tibiofibular ligament (AITFL) tubercle of the fibular with the anterior tibial incisura would precipitate lateral translation due to the size differential. Methods: Twelve cadaveric ankle specimens were dissected, removing all soft tissue except for ligaments. They were fixed onto a bespoke jig allowing tibial fixation and free movement of the talus and fibula. The fibula was progressively shortened in 5mm increments until complete ankle dislocation, measuring the medial clear space with each increment. Results: The larger AITFL tubercle interaction with the smaller tibial incisura caused a significant increase in lateral translation of the talus. This occurred in most ankles between 5-10mm of fibular shortening. The medial clear space widened following 5mm of shortening in 5 specimens (mean: 2.07, s.d: 2.53). All 12 specimens experienced widening by 10mm fibular shortening (Mean: 7.21mm, s.d: 2.21) and reached complete dislocation by 35mm fibular shortening. Conclusion: This study shows, that with fibular shortening, the interaction between the distal fibular AITFL tubercle and the anterior tibial incisura precipitates a lateral translation of the talus in an ankle fracture model where the medial and syndesmotic ligaments have been transected and the lateral ligaments remain intact. The interaction occurred between 5 and 10mm of fibular shortening. Beyond this point there was a near linear correlation between fibular shortening and medial clear space widening

Lateral talar subluxation (LTS) in SER ankle fractures is more responsive than medial clear space widening: A cadaveric biomechanical study

Category: Ankle; Trauma Introduction/ Purpose: Supination-external rotation (SER) ankle fractures are characterized by posterolateral translation and external rotation. In isolated fibula fracture SER variants, medial soft tissue structure incompetence can be identified with medial clear space (MCS) widening or with lateral talar subluxation (LTS), frequently obtained on stress view imaging. This assessment is a key determination of which patients may require surgical management to restore ankle joint stability. Current radiographic studies demonstrated increased sensitivity and specificity of LTS versus MCS which may be due to increased rotational movement occurring in the direction of the talar displacement. Biomechanical data has not yet been established. The purpose of this study was to investigate MCS and LTS displacements in a cadaveric biomechanical study to confirm this rotational movement principle in a controlled setting. Methods: An open approach was utilized to surgically create an SER isolated fibula fracture in five below-knee cadaveric specimens. Open anteromedial and lateral ankle approaches were created for visualization of the medial and lateral structures, also allowing direct measurement of the MCS and LTS with a ruler. There was no ankle instability prior to injury, MCS and LTS were zero in each specimen prior to experimental model creation. An SER-pattern fibular osteotomy was made with an oscillating saw. The superficial and deep deltoid were then released from the medial malleolus, and the foot was displaced maximally creating an SER-4b variant ankle fracture. The MCS and LTS were then measured. Differences were analyzed using a paired Student’s t-test. Effect size (Cohen’s d) was measured to characterize statistical significance and determine relative importance in the degree of change. Results: There was no underlying ankle stability, deformity, or arthritis in any of the 5 cadaveric ankle specimens. In our simulated SER-4b ankle fractures, the mean MCS widening using medial landmarks was 7.2 mm (+/- 1.3mm). The mean lateral displacement utilizing the LTS landmarks was 11.2mm (+/- 1.3mm). The difference between medial and lateral displacement was found to be statistically significant (p = 0.0067, 95% CI [1.85, 6.15]). Cohen’s d was equal to 3.1 (95% CI [1.24, 4.90]), demonstrating a large effect size, showing the mean to be different by 3 standard deviations. The increase in mean lateral displacement was 43% greater when compared to the mean medial displacement. Conclusion: In this cadaveric study, LTS displacement was significantly greater than MCS widening following simulation of SER type IV ankle fracture injuries. The effect size of 3.1 confirms statistical significance. This data supports that talus external rotation is a significant factor in SER pattern displacement. The rotational moment arm is largest laterally with external rotation, and posterolateral displacement. Our study supports the idea of measuring the LTS radiographically as a marker to assist in surgical decision-making. Further characterization of the displacement pattern of SER injuries will be helpful to assist surgical decision- making in these common ankle injuries.

Midterm Follow-up of a Novel Algorithm for Nonoperative Weber B Ankle Fractures.

Stable Weber B ankle fractures are routinely treated nonoperatively. Our group previously presented a novel algorithm that provides radiographic parameters guiding when Weber B ankle fractures can be treated nonoperatively.2 The purpose of this study is to evaluate the durability of those results with a minimum 5-year follow-up. All 51 patients who were included in the initial study were contacted by telephone and asked to return to clinic for repeat evaluation where American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot, Olerud-Molander Ankle (OMA), and visual analog scale (VAS) scores were collected. Bilateral standing ankle radiographs were obtained and evaluated using the Kellgren-Lawrence grading scale for ankle arthritis. Twenty-nine of 51 patients (56%) participated in this follow-up study with a mean follow-up of 6.8 (range 5.6-8) years. Average functional score results were as follows: AOFAS, 98.43; OMA score, 94.11; and VAS, 0.46. AOFAS scores improved by an average of 5 points between 1 year and 5 years (P = .002); OMA and VAS scores were stable. All patients achieved union of their fracture on follow-up radiographs. Our findings demonstrate the durability of the previous study results conducted by Holmes et al,2 and support that appropriately selected patients can be treated nonoperatively using the study's novel algorithm. This reinforces our theory that medial clear space widening on weightbearing radiographs up to 7 mm should be considered for nonoperative management. Level IV, case series.

Acute Deep Deltoid Ligament Reconstruction using a Novel, Arthroscopically-Assisted Technique: Case Report

Category: Arthroscopy; Ankle; Sports; Trauma Introduction/Purpose: The deltoid ligament complex is the main stabilizing structure of the ankle mortise and is often disrupted in rotational ankle injuries. Current treatment involves open techniques for the acute repair of the superficial deltoid layer, however, repair or reconstruction of the deep deltoid ligament (DDL) has proven to be challenging using open techniques. Our described arthroscopically-assisted technique allows for better intra-articular visualization and durable reconstruction of the ruptured DDL with suture and knotless bone anchors. The goal of this new, minimally invasive approach is to facilitate a faster and more reliable recovery and prevent long-term dysfunction and degeneration from medial and rotational ankle instability. We believe it has the potential to provide improved immediate ankle stability and decrease overall surgical morbidity compared to open treatments. Methods: Case of a 48-year-old male with ligamentous-equivalent Massioneuve fracture with medial clear space (MCS) measuring 11 millimeters. Arthroscopy revealed unstable syndesmosis and rupture of the DDL. After syndesmotic fixation, there was persistent MCS widening on stress exam. Arthroscopically-assisted DDL reconstruction was performed using an accessory anteromedial (AAM) portal between the tibialis anterior tendon and posterior tibial tendon. Needle localization identified the sagittal midpoint of the medial wall of the talus, inferior to articular cartilage. Anchor sites at both the medial talar wall and midportion of the distal medial malleolus (insertion and origin of the DDL, respectively) were then drilled via the AAM portal under arthroscopic and fluoroscopic guidance respectively at the isometric point. A suture anchor was placed into the talus and tails were loaded and secured to the medial malleolus with a bioabsorbable anchor. Ankle mortise was stable to stress exam and there were no restraints to physiologic motion. Results: The patient was kept non-weight bearing on his right lower extremity for a total of 6 weeks postoperatively and was seen in the clinic for routine follow-up visits at 2 weeks, 6 weeks, and 3 months post-procedure. Sutures were removed at 2 weeks, without any wound complications, and he was transitioned from splint to a short leg cast. He required only three days of oral narcotic analgesia. Weight-bearing in a controlled ankle motion (CAM) boot and physical therapy were both initiated at 6 weeks post-op. Radiographs at each follow-up visit were without abnormalities. At 3 months post-op, he was graduated from the CAM boot into a lace-up ankle brace, without any complaints of ankle pain or instability. The patient progressed well with full weight-bearing and physical therapy and was seen for a final visit at 5 months post-op with stable MCS. No complications were encountered. Conclusion: Acute DDL rupture is a common occurrence in ankle fractures and can be diagnosed radiographically and by arthroscopy. Known sequelae of untreated DDL disruption include medial instability and late valgus collapse. This case report demonstrates a novel, minimally invasive technique to successfully reconstruct the DDL, which may minimize the surgical morbidity compared to open dissection methods and allow for decreased recovery time postoperatively. This approach may also be utilized for cases of chronic instability. Future work includes larger case series with long-term follow-up and refinement of the technique as instrumentation advances.

The Lateral Drawer Test: A New Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures.

Background:Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability. The goal of this study is to test the validity of a new clinical examination maneuver, the lateral drawer test, against the gravity stress view (GSV) in a cohort of patients with Weber B fibula fractures. Secondary goals included assessing pain tolerability of the lateral drawer test, as well as testing interobserver reliability.Methods:Sixty-two patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three nonweightbearing radiographic views of the ankle as well as a GSV were obtained. Radiographs were not visualized before conducting the lateral drawer test. Two foot and ankle fellowship–trained orthopaedic surgeons performed and graded the lateral drawer test. Radiographs were then examined and medial clear space (MCS) was measured. Visual analog scale (VAS) pain scores were obtained before and after testing. The results of the lateral drawer test were compared with radiographic measurements of MCS on GSV. A cadaveric experiment was devised to assess interobserver reliability of the lateral drawer test.Results:Thirty (48%) of 62 consecutively enrolled patients demonstrated radiographic instability with widening of the MCS ≥5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 86%. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (Spearman correlation ρ = 0.82, P < .005). Patients tolerated the maneuver well with an average increase of 0.7 on the VAS pain scale. Testing of 2 observers utilizing the cadaveric model demonstrated a Cohen’s Kappa coefficient of 0.7 indicating moderate interobserver agreement.Conclusion:The lateral drawer test demonstrates high sensitivity, specificity, PPV, and NPV with moderate interobserver reliability compared with the MCS on GSV in patients presenting with Weber B fibula fractures. Although further external validation is required, the lateral drawer test may offer an adjunct tool via physical examination to help determine mortise stability.Level of Evidence:Level II, Prospective Cohort Study.

Impact of Weber B Fracture Displacement on Medial Clear Space Volume: How Much Displacement Matters?

Category:Ankle; Sports; TraumaIntroduction/Purpose:Numerous radiographic studies examining Weber B fibular fractures demonstrate no change in tibiotalar contact area until the deltoid ligament is disrupted. In contrast, more recent studies using weight-bearing CT scan (WBCT) and 3D volume analysis suggest that medial clear space (MCS) volume can in fact increase in the setting of a Weber B fibular fracture even if initial radiographs are reassuring, possibly due to a loss of fibular buttress. This study aims to evaluate the ability of WBCT to quantify the impact of isolated Weber B fractures on MCS volume (3D), as well as understand the implication of increasing fibular displacement among patients with symmetric MCS distance (1D) on initial radiographs.Methods:The study group included 18 patients with unilateral Weber B ankle fractures who underwent preoperative bilateral foot and ankle WBCT. The control group consisted of 60 patients without ankle injury who underwent similar imaging.Measurements on WBCT images included: 1) MCS distance, 2) syndesmotic area, 3) anterior, middle, and posterior distal tibiofibular distance, 4) fibular rotation, 5) distance from fibular tip to plafond, and 6) fibular fracture displacement. Additionally, volumetric measurements included: 1) MCS volume 2) syndesmotic joint volume from the tibial plafond extending to 3cm and 5 cm proximally, and 3) lateral clear space volume were calculated. Area under the receiver operating characteristic (ROC) curve analysis and Delong test were used, and optimal cutoff values to distinguish between stable and unstable Weber B fractures without syndesmotic instability and MCS widening were determined using Youden's J statistic.Results:Among patients with unilateral Weber B ankle fractures, all WBCT measurements showed no side-to-side difference in any parameter, except MCS volume (p-values <0.001). When compared to the uninjured side, fibular displacement up to 2cm and up to 4cm increased lateral MCS volume by 37.1% (0.23cm3) and 51.8% (0.3cm3), respectively. Based on ROC analysis and Youden's J statistic, the optimal threshold for differentiating stable from an unstable Weber B fracture was 2.3 mm of displacement (AUC 0.81; sensitivity 77.8%; specificity 80%). The control group showed no difference in any of the measurements between the two sides.Conclusion:When using WBCT, 3D MCS volume increases significantly with Weber B fibular fractures, even if 1D distance measurements at the medial clear space are reassuring. This is especially true with fibular displacement greater than 2.3mm and may have an important role in the management of SER II ankle fractures.

Effectiveness of a Superelastic Nitinol Device for Fixation of Syndesmosis in Ankle Fracture

Category:Ankle; TraumaIntroduction/Purpose:Syndesmosis injuries are increasingly common. Available fixation options are not yet optimal. The PUMA System (Panther Orthopedics, Sunnyvale, CA) is an FDA-cleared superelastic, nitinol-based fixation device for the ankle syndesmosis which provides stabilization without over-compression or loosening during cyclical loading. The spring-like design of the PUMA System allows physiological micro-motion while maintaining continuous compression and resisting syndesmosis widening, without material creep. The objective of this prospective study is to assess the effectiveness and complication rate of the PUMA device for treatment of fracture-associated syndesmosis injuries.Methods:We prospectively collected radiographic and clinical data on 32 consecutive patients treated for fracture-associated syndesmotic disruption with the PUMA SystemTM at 8 centers. Primary outcome measures included adverse event rates, radiographic evaluations for syndesmosis integrity and implant failure, and rates of revision surgery.Results:All 32 patients had successful repair of their ankle syndesmosis (Figure 1). The mean age of patients at time of operation was 42 years (range 16- 68). There were 13 females (13/32, 40.6%) and 19 (19/32, 59.4%) males. Postoperative radiographic evaluations confirmed satisfactory syndesmosis healing with maintained reduction in the ankle mortise in 33/33 (100%) ankles. There was no evidence of lysis, device migration or syndesmotic or medial clear space widening. There were no infections or soft tissue complications. All fractures healed. No devices required removal and there were no revision surgeries.Conclusion:The PUMA SystemTM provides physiologic stabilization of the syndesmosis due to the design features that allow for continuous compression without creep. We found no device-related complications nor construct failures in our series. The superelastic implant design allows physiologic motion at the syndesmosis but does not creep or stretch following displacement. This flexibility obviates the need for routine removal. The implant's low-profile buttons without suture and knot tying requirements eliminate the concern for subcutaneous knot irritation and slippage. Additional biomechanical and clinical outcomes study of this device may further optimize rehabilitation protocols for patients treated for syndesmotic injury.

Diagnosing Medial Ankle Instability with Gravity Stress, Weight-Bearing, and External Rotation Stress Ultrasonography: A Cadaveric Study

Category:Ankle; TraumaIntroduction/Purpose:Destabilizing injuries to the deltoid ligament have historically relied on radiographic stress examination for diagnosis, with a focus on medial clear space (MCS) widening. Increasingly, Portable ultrasound (P-US) has increasingly been used in the clinical setting, allowing dynamic and non-invasive evaluation at the point of care. This study aims to determine whether the P-US assisted MCS evaluation during the gravity stress (GST), weight-bearing, and external rotation stress test can detect medial side instability in supination-external rotation (SER) type ankle injuries with sequential disruption of the anterior inferior tibiofibular ligament (AITFL) (stage I), the fibula (Weber B fracture) (stage II), the posterior inferior tibiofibular ligament (PITFL) (stage III), the superficial deltoid ligament (stage IVa) and the deep deltoid ligament (stage IVb).Methods:Ten fresh-frozen cadaveric specimens were used. Medial ankle instability was assessed by the P-US. The assessment was performed with all structures intact and later with sequential transection of the AITFL, Weber-B fibular fracture, the PITFL, the superficial and deep deltoid ligament. In all scenarios, three loading conditions were considered, including the GST, the external rotation stress test (45N), and the simulated weight-bearing (750N). The P-US measurement of the MCS was assessed at the anteromedial aspect and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. To investigate the correlation between the P-US measurements and the staging of SER ankle injuries, a Spearman rank correlation was used. To detect a difference in MCS distances between each injured stage and the intact stage for each stress test, a Wilcoxon signed-rank test was used. P-values were adjusted for multiple comparisons using the Holm- Bonferroni method.Results:MCS values measured with the P-US increased as the SER ankle injury stage progressed. The Spearman's rank correlation coefficient ranged from 0.43 to 0.90 (p-values <0.001), which represent moderate to strong positive correlations between the ultrasonographic MCS measurements, and the sequentially created supination-external rotation ankle injury model. All MCS values measured with the P-US during; 1) the GST in neutral ankle position, 2) the GST in plantarflexed ankle position, 3) weight-bearing, and 4) the external rotation stress test, were significantly different between intact stage vs. stage IVb (p ranged from 0.02-0.03). When compared between SER ankle injury stage IVa vs. IVb, the P-US MCS values measured in SER stage IVb were significantly larger (p ranged from 0.005-0.03). Inter-rater (0.97; 95% confidence interval: 0.96-0.98) and intra-rater reliability (0.95; 95% confidence interval: 0.94-0.96) for the P-US MCS measurements were all substantial.Conclusion:Portable ultrasonography is a feasible tool for diagnosing medial ankle instability in SER ankle injury. The MCS measurements assessed with P-US during the GST, weight-bearing, and the external rotation stress test well correlated with the SER ankle injury staging. Besides, the P-US method is capable of differentiating the SER ankle injury stage IVb from the intact stage, as well as differentiating the stable SER ankle injury stage from the unstable stage. Therefore, the P-US can be a valuable diagnostic tool at the point of care due to its ability to dynamically evaluate suspect medial ankle instability in SER type injury.

Retrospective Chart Review: Weight Bearing CT Scans and the Measurement of the Tibiofibular Syndesmosis

Category:AnkleIntroduction/Purpose:Tibiofibular Syndesmosis injuries are commonly misdiagnosed due to their unreliable projection on plain films. Many studies have striven to establish baseline measurements of the distal tibial and fibular articulation. While cadaver, MRI, ultrasound, and non-weight bearing computer tomography (CT) have been utilized, weight bearing CT (WBCT) scans are a relatively new imaging modality that has not yet been utilized to establish reproducible and widely-referenced baseline anatomic positions. The hypotheses of this study are: 1. Standing, weight bearing CT scan will allow for evaluation and measurement of the tibio-fibular syndesmosis. 2. There will be no side to side variation or sex-based differences in syndesmosis measurements.Methods:A retrospective chart review was conducted using the electronic medical record. Inclusion criteria was applied as follows: Patients who have undergone weight bearing CT of the bilateral lower extremities from 2018 to 2020. One hundred twenty ankle CT scans were acquired for measurements. Measurements were collected by two independent reviewers twice in order to achieve inter- and intra-reliability. The measurements were then analyzed in order to establish a baseline for normal anatomy, compare injured to non-injured side, and observe any sex-based differences.Results:Measurements of uninjured legs were utilized to define normal parameters for tibiofibular syndesmosis on weight bearing CT. Averages were found for measurements of anterior incisura 3.2mm (SD=1.1mm), middle incisura 3.9mm (SD=1.1mm), posterior incisura 5.6mm (SD=1.7mm), alpha angle 16.3° (SD=6.3°), medial clear space 2.2mm (SD=0.6mm).Patients with syndesmotic injuries had significantly larger measurements for anterior (p<0.0001), middle (p=0.0007), and posterior incisura (p=0.002) when compared to uninjured ankles. Males had significantly higher medial clear space widening (p=0.0012) compared to female patients. Anterior incisura (p <0.0001), posterior incisura (p=0.0005) were found to significantly decrease as age increased.Conclusion:This study aims to assist in defining baseline anatomic measurements for syndesmotic parameters. The values and comparisons obtained were able to reinforce that weight bearing CT is valuable in identifying subtle injuries to the TFS while also demonstrating that there is male-to-female and age-related differences that should be kept in mind when radiographically evaluating imaging studies of injured patients.

The Lateral Drawer Test: A Novel Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures

Category:Trauma; AnkleIntroduction/Purpose:Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. While instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the apparent isolated Weber B fibula fracture often requires further investigations such as stress radiography. While several authors have previously demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis and swelling with instability, no previous investigation has examined the ability of a translational test to determine deltoid ligament injury. The goal of this study is to test the validity of a novel clinical test, the lateral drawer test, in determining mortise instability in a cohort of patients with Weber B fibula fractures.Methods:Patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three views of the ankle as well as gravity stress views (GSV) were obtained. Prior to examining radiographs, two foot & ankle fellowship-trained orthopaedic surgeons (JYK, CPM) performed and graded the lateral drawer test. (Grade 0: no instability/symmetric to contralateral ankle, Grade I: translation < 5mm, Grade II: translation >= 5mm) While the surgeons were made aware of the presence of a Weber B fibula fracture, radiographs were not visualized prior to conducting the drawer test.Medial clear space (MCS) was measured. VAS pain scores were obtained before and after testing. The results of the lateral drawer test results were compared with radiographic measurements of MCS.Results:The study enrolled 57 consecutive patients with Weber B ankle fractures. Twenty-nine (51%) patients demonstrated radiographic instability with widening of the medial clear space >= 5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83.3%, specificity of 96%, positive predictive value (PPV) of 96% and negative predictive value (NPV) of 84% for determining instability. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (⍴=0.82, p<0.001). Patients tolerated the lateral drawer test well with an average increase of 0.8 points on the VAS pain scale after testing.Conclusion:The lateral drawer test demonstrates high sensitivity, specificity, PPV and NPV for detecting instability in patients presenting with Weber B fibula fractures. While further validation is required in a larger cohort of patients, the lateral drawer test may offer an adjunct tool via physical examination to predict mortise stability.

Fibular displacement does not predict instability in type B ankle fractures.

Despite the wide prevalence of ankle fractures, no consensus exists on the most accurate radiologic diagnostic tool to indicate medial ligament injury in isolated type B distal fibular fractures. The aim of this study was to evaluate the value of the fibular fracture displacement in predicting medial clear space widening on the gravity stress radiographs, as a parameter of fracture instability. This retrospective cohort study included 192 patients with an isolated type B fibular fracture, for which a regular mortise and gravity stress radiograph were made in our hospital between January 2014 and December 2019. On the regular mortise and lateral radiographs, the medial clear space (MCS), superior clear space (SCS), anteroposterior and lateral fibular displacement were measured. On the gravity stress radiograph, the MCS and SCS were measured. Instability was defined as MCS ≥ SCS + 3.0mm on the gravity stress radiograph. A receiver operating characteristic (ROC) curve was constructed to evaluate the predictive value of the fibular displacement. Of the 192 included patients, 55 (29%) patients had instable ankle fractures. In predicting instability, fibular displacement demonstrated an area under the curve (AUC) of 0.68 (95% confidence interval 0.60-0.77) and a correlation coefficient of 0.41 with MCS. Fibular displacement on regular mortise view is a poor predictor of instability in type B fibular fractures. It should not be advised to use the fracture displacement as parameter for medial injury and thus for operative treatment.

Deltoid Ligament Injuries Associated With Ankle Fractures: Arguments For and Against Direct Repair.

Ankle fractures are an extremely common orthopaedic injury treated by surgeons on a routine basis. The deltoid ligament is torn in a large number of these fractures and is commonly seen with associated radiographic changes of medial clear space widening. The clinical relevance of addressing the injured deltoid ligament with acute surgical repair has been debated for decades. The early literature documenting repair or reconstruction of the deltoid ligament dates back to the 1950s. Most commonly, orthopaedic surgeons restore the lateral column directly with fibula fracture fixation. The injury may then be further evaluated intraoperatively by stress testing to ensure syndesmosis integrity and mortise stability with indirect medial column reduction, which allows for secondary healing of the medial deltoid ligamentous complex. This popular treatment paradigm is based primarily on literature from the 1980s and has not been thoroughly evaluated with modern surgical implants, techniques, and research methods. A review and background of the supportive literature for and against deltoid ligament repair in the setting of acute ankle fractures is presented. Undeniably, the deltoid ligament complex has been proven to confer some element of stability to maintaining a congruent ankle mortise. The commonly cited data in favor of not repairing the deltoid ligament warrants careful consideration to allow accuracy in obtaining the best patient outcomes with the most predictable surgical methods available.

Medial Ankle Stability Evaluation With Dynamic Ultrasound: Establishing Natural Variations in the Healthy Cohort.

Destabilizing injuries to the deltoid ligament have relied on radiographic stress examination for diagnosis, with a focus on medial clear space (MCS) widening. Recently, studies have demonstrated the use of ultrasonography to assess deltoid ligament injury, but not the medial ankle stability. The purpose of this study was to assess the MCS via ultrasonography while weight-bearing and with a gravity stress test (GST) in the uninjured ankle as a means of establishing normative values for future comparison. Twenty-six participants with no reported ankle injury in their premedical history were included. The MCS was examined using ultrasonography with the patient lying in a lateral decubitus position to replicate a GST with the ankle held in a neutral and plantarflexed position as well as while weight-bearing. The MCS was assessed in mm at the anteromedial and inferomedial aspect of the ankle joint. With weight-bearing, the average anterior MCS and inferior MCS were 3.6 and 3.3 mm, respectively. During the GST in neutral ankle position, the average anterior MCS was 4.1 mm, whereas the average inferior MCS was 4.0 mm. When measured during the GST in plantarflexed ankle position, the averages anterior MCS and inferior MCS increased to 4.4 mm. MCS values were notably higher with GST than with weight-bearing measurements (P < 0.001). MCS values were notably higher with the foot in a plantarflexed compared with a neutral position when doing GST (P < 0.001). No notable differences in MCS distance were found when comparing laterality (P > 0.05). Height had a notable effect on all MCS values (P < 0.05). Inter- and intra-rater reliabilities for ultrasonographic MCS measurements were all excellent (interclass correlation coefficient >0.75). Ultrasound can reliably measure the MCS of the ankle while doing dynamic stress manoeuvres. With the deltoid ligament intact, a GST increases MCS widening more than weight-bearing, and holding the ankle in plantarflexion while doing a gravity stress view, further increases this difference. Diagnostic studies-investigating a diagnostic test: Level III.

Correlating Arthroscopic and Radiographic Findings of Deep Deltoid Ligament Injuries in Rotational Ankle Fractures.

The deep deltoid ligament (DDL) is a key stabilizer to the medial ankle and ankle mortise and can be disrupted in ligamentous supination external rotation type IV (LSER4) ankle fractures. The purpose of this study was to define the medial clear space (MCS) measurement on injury mortise radiographs that corresponds with complete DDL injury. A retrospective record review at a level 1 hospital was performed identifying patients with LSER4 ankle fractures who underwent arthroscopy and open reduction internal fixation. Chart reviews provided arthroscopic images and operative reports. Complete DDL injury was defined as arthroscopic visualization of the posterior tibial tendon (PTT). Inability to completely visualize the PTT was defined as a partial DDL injury. MCS was measured on injury mortise radiographs. Eighteen subjects met inclusion criteria. Twelve subjects had complete and 6 subjects had partial DDL injury based on arthroscopic findings. Patients with complete DDL injury and those with partial DDL injury had injury radiograph MCS ranging from 5.5 to 29.9 mm and 4.0 to 5.0 mm, respectively. All patients with MCS ≥5.5 mm on injury radiographs had complete DDL injury and all patients with MCS ≤5.0 mm on injury radiographs had partial DDL injury. Complete DDL injury was found on injury ankle mortise radiographs as MCS widening of ≥5.5 mm, which correlated with arthroscopic visualization of the PTT. Using this cutoff, surgeons can surmise the presence of a complete deltoid ligament injury, allowing for improved preoperative planning. Level III, retrospective comparative study.

Kinematics after Syndesmotic Injury: Assessing the Magnitude of Talus and Fibula Rotation and Displacement

Category:Ankle; Sports; OtherIntroduction/Purpose:High ankle sprains, or injuries to the distal tibiofibular syndesmosis, are predictive of long-term ankle dysfunction. Our objectives were to evaluate ankle mortise stability, radiographically, and kinematically, using a cadaveric model with a simulated syndesmotic injury. We also measured the ability of a suture-button system to restore natural joint motion.Methods:Eight cadaveric specimens underwent serial sectioning of the anterior-inferior tibiofibular (AITFL), interosseous (IOL), posterior-inferior tibiofibular (PITFL), and deltoid ligaments. Specimens underwent external rotation and lateral translation testing after ligament release to obtain kinematic data (using a validated infrared LED motion capture system) and radiographic measurements. We then repeated external rotation and lateral translation testing after implementing a suture-button system. Repeated measures ANOVA with a Bonferroni/Dunn post-hoc test calculated the interspecimen comparisons.Results:Sectioning of each ligament, beginning with the AITFL, significantly increased talar external rotation. After releasing the AITFL and IOL, fibular external rotation increased significantly. Posterior displacement of the fibula began following the release of AITFL. Significant radiographic widening of the medial clear space and the syndesmosis occurred only after the release of the deltoid ligament. Syndesmotic and medial clear space widening was not significantly different from the intact state under lateral translation until after the release of the deltoid ligament. Placement of the suture-button system successfully reduced the medial clear space but was unable to restore the native stability of the ankle joint.Conclusion:This project addresses rotational and kinematic changes in the ankle after syndesmotic injury by quantifying the effect of ligamentous disruption on the tibiotalar articulation. The change in joint kinematics may explain why patients with moderate-to-severe syndesmosis injuries take longer to heal and develop long-term dysfunction. Significant talar rotation and posterior fibular displacement occur during external rotation, even with moderate syndesmosis injury, and before the disruption of the deltoid ligament. Stress radiography does not appear to be a reliable indicator of mild or moderate syndesmosis injuries.

The Lateral Drawer Test: A Novel Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures

Category:Ankle; TraumaIntroduction/Purpose:Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. While instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the apparent isolated Weber B fibula fracture often requires further investigations such as stress radiography. While several authors have previously demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis and swelling with instability, no previous investigation has examined the ability of a translational test to determine deltoid ligament injury. The goal of this study is to test the validity of a novel clinical test, the lateral drawer test, in determining mortise instability in a cohort of patients with Weber B fibula fractures.Methods:Patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three views of the ankle as well as gravity stress views (GSV) were obtained. Prior to examining radiographs, two foot & ankle fellowship-trained orthopaedic surgeons (JYK, CPM) performed and graded the lateral drawer test. (Grade 0: no instability/symmetric to contralateral ankle, Grade I: translation < 5mm, Grade II: translation >= 5mm) While the surgeons were made aware of the presence of a Weber B fibula fracture, radiographs were not visualized prior to conducting the drawer test.Medial clear space (MCS) was measured. VAS pain scores were obtained before and after testing. The results of the lateral drawer test results were compared with radiographic measurements of MCS.Results:The study has thus far prospectively enrolled 14 consecutive patients with Weber B ankle fractures. Six (43%) patients demonstrated radiographic instability with widening of the medial clear space >= 5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83.3%, specificity of 100%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 88.9% for determining instability. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (⍴=0.82, p=0.0003). Patients tolerated the lateral drawer test well with an average increase of 1.6 on the VAS pain scale after testing.Conclusion:The lateral drawer test demonstrates high sensitivity, specificity, PPV and NPV for detecting instability in patients presenting with Weber B fibula fractures. While further validation is required in a larger cohort of patients, the lateral drawer test may offer an adjunct tool via physical examination to predict mortise stability.

Effect of Muscle Activation on the Gravity Stress View in Unstable Weber B Ankle Fractures.

In the setting of apparently isolated distal fibula fractures, the gravity stress view (GSV) is a validated method to determine mortise stability. There is currently no published data evaluating whether dynamic muscle activation can reduce an unstable mortise. If patients with instability can overcome gravity, resultant images could yield false-negative results. The goal of this investigation was to determine if patient effort can influence medial clear space (MCS) measurements in proven unstable bimalleolar-equivalent ankle fractures. Patients presenting with Weber B fibula fractures were assessed for mortise stability using the GSV. If the GSV demonstrated instability based on MCS widening >4 mm, 3 additional views were performed: GSV with an assistant maintaining the ankle in a neutral position; GSV with the patient actively dorsiflexing to neutral; and GSV with the patient actively dorsiflexing and supinating the foot. Twenty-four consecutive patients met inclusion criteria, with a mean age of 48.7 (range, 22-85) years. Fifteen patients (62.5%) were female and 9 (37.5%) were male. The laterality was evenly divided. The mean MCS was 5.8 ± 2.0 6.0 ± 2.6, and 6.2 ± 2.7 mm for the manual assist, active dorsiflexion, and active supination radiograph measurement groups, respectively (P = .434). Only 5 of 24 subjects had any measurable decrease in their MCS with active supination, with a maximum change of 1.2 mm. The remainder of the patients had an increase in MCS ranging from 0.1 to 4.0 mm. There was no significant difference between measurement states indicating that muscle activation is unlikely to yield a false-negative result on GSV. Mortise instability, secondary to deep deltoid injury in the presence of gravity stress, is unlikely to be actively overcome by dynamic stabilizers, supporting the validity and specificity of the GSV. Level III, prospective study.

Safety of Early Weight Bearing Following Fixation of Bimalleolar Ankle Fractures.

Ankle fractures are common orthopedic injuries. Although operative indications and subsequent stabilization of these fractures have not significantly changed, postoperative protocols remain highly variable. Effects of early weight bearing (EWB) on fracture characteristics in operatively stabilized bimalleolar and bimalleolar equivalent ankle fractures remain poorly publicized. This study seeks to clarify postoperative fracture union rates, rates of hardware loosening or failure, and radiographic medial clear space changes when comparing EWB to late weight bearing (LWB) following open reduction and internal fixation (ORIF).A total of 95 patients with either bimalleolar (66%) or bimalleolar equivalent (34%) fractures who underwent ORIF were retrospectively reviewed. Weight bearing was allowed at three weeks in the EWB group and when signs of radiographic union were noted in the LWB group. Postoperatively, patients were evaluated at regular intervals for fracture union, signs of implant failure, and evidence of medial clear space widening radiographically.There were 38 patients (40%) in the EWB group and 57 patients (60%) comprising the LWB cohort. There were no significant demographic differences between groups. The EWB group on average began to weight bear at 3.1 + 1.4 weeks postoperatively, whereas the LWB group began at 7.2 + 2.1 weeks postoperatively (p<0.01). Union rate (p=0.51), time to union (p=0.23), and implant failure (p>0.1 at all time intervals) were not notably different between groups. No differences in medial clear space were detected at any postoperative interval between groups (p>0.1 at all time intervals). This study suggests that EWB at three weeks postoperatively does not increase markers of radiographic failure compared to six weeks of non-weight bearing (NWB), which has been regarded as the gold standard of treatment to allow for healing; this may represent an improvement to rehabilitation protocols after bimalleolar ankle ORIF of unstable ankle fractures.