Gravity Stress Radiographs and the Effect of Ankle Position on Deltoid Ligament Integrity and Medial Clear Space Measurements

The Use of the Lateral Tibial Line to Assess Ankle Alignment: A Preliminary Investigation

BACKGROUND

Although the medial clear space (MCS) is commonly used to assess talar alignment and ankle stability, its measurement is variable with multiple reported normal values. We have observed that the lateral tibial shaft is a reliable landmark to assess talar alignment. The objective of the current investigation was to determine the normal relationship of the lateral tibia to the superolateral talus using a tangent drawn inferiorly from the lateral tibial shaft, which we refer to as the "lateral tibial line" (LTL).

METHODS

The relationship of the LTL to the superolateral talus was assessed by three reviewers on 99 standing ankle mortise radiographs in uninjured patients. This relationship was quantified by measuring the distance (in millimeters) between the LTL and the superolateral talus. In addition, the interobserver reliability of the LTL measurement was recorded and compared with that of the MCS.

RESULTS

The median value for the distance between the superolateral talus and LTL was -0.50 mm with an interquartile range of -1.4 to 0.0 mm. The LTL was within 1 mm of the lateral talus in 176 of 297 reviewer measurements (59.3%). Moreover, it was either lateral to or at most 1 mm medial to the lateral talus in 90.9% of cases. The LTL measurement also demonstrated good interobserver reliability (0.764, 95% confidence interval, 0.670 to 0.834), similar to the measurement of MCS (0.742, 95% confidence interval, 0.539 to 0.846).

CONCLUSIONS

The relationship between the LTL and superolateral talus is easily measured with good reliability for assessing the anatomic relationship of the tibia and talus. The LTL uncommonly fell more than 1 mm medial to the superolateral talus, as might be seen with displaced ankle fractures. These findings will hopefully serve as a basis for future studies evaluating its role in assessing lateral displacement and stability of isolated fibula fractures.

LEVEL OF EVIDENCE

Level III, retrospective review.

Bone marrow edema at ligament insertion is an accurate MRI sign of deltoid ligament injury

BACKGROUND

Magnetic resonance imaging (MRI) is effective in diagnosing deltoid ligament (DL) injury but its sensitivity in chronic cases is low. Additional diagnostic signs are required to reduce the risk of a false negative diagnosis.

PURPOSE

To evaluate the added diagnostic value of bone marrow edema at the ligament insertion (BMELI) of DL to the MRI assessment of chronic DL injury.

MATERIAL AND METHODS

One hundred patients who consecutively came to our institution between November 2018 and December 2021 and underwent arthroscopic surgery for chronic ankle instability (CAI) were enrolled in the present study. Preoperative MR images were retrospectively reviewed by two orthopedic surgeons to evaluate the sensitivity, specificity and interobserver reliability of three MRI signs in diagnosing chronic DL injury, namely, abnormal ligamentous morphological characteristics (ALMC), BMELI and medial clear space (MCS).

RESULTS

Taking arthroscopy as the reference standard, there were 34 patients with and 66 without DL injury. ALMC had 64.71% (22/34; 46.47-79.70) sensitivity and 83.33% (55/66; 71.71-91.00) specificity, BMELI had 70.59% (24/34; 52.33-84.29) sensitivity and 95.45% (63/66; 86.44-98.82) specificity and MCS had 26.47% (9/34; 13.51-44.65) sensitivity and 92.42% (61/66; 82.50-97.18) specificity. Compared with ALMC, BMELI had similar efficacy in superficial cases (P = 0.06) and greater efficacy in deep cases (P = 0.04). All three signs showed good interobserver agreement (kappa values all above 0.7).

CONCLUSION

BMELI can reliably indicate concomitant injury to the DL in CAI patients. Using BMELI as a sign of chronic DL injury when ALMC is unclear may reduce the risk of a false negative diagnosis.

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

OBJECTIVES

To determine whether 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 findings.

METHODS

DESIGN

Prospective cohort.

SETTING

Level 1 academic trauma center.

PATIENT SELECTION CRITERIA

Nonoperatively managed patients with isolated OTA/AO 44B fractures and MCS ≤4 mm on initial non-weightbearing injury radiographs between from January 2018 and January 2022 were included. All patients underwent emergency department gravity stress radiographs and those with widening were considered the widening cohort and those without the non-widening cohort.

OUTCOME MEASURE AND COMPARISONS

MCS measurements on weightbearing radiographs were obtained at first follow-up, 6 weeks, 12 weeks, and 6 months postinjury, were considered indicative of instability if >4 mm and were compared between cohorts.; American Orthopaedic Foot and Ankle Society ankle-hindfoot scores were also compared between cohorts.

RESULTS

Sixty-nine patients were studied. None of the 38 patients (55%) with widening on gravity stress radiographs demonstrated widening with weightbearing radiographs at any time point. Mean MCS measurement differences between the 2 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 nonwidening cohort and 2.9 mm for the widening cohort, these are not clinically significant. There was no statistically significant difference in overall final American Orthopaedic Foot and Ankle Society scores between the 2 groups ( P = 0.451). In addition, statistical equivalence using Schuirmann 2 one-sided tests was achieved between the 2 groups. Both cohorts had mean American Orthopaedic Foot and Ankle Society scores representing excellent outcomes at the final follow-up.

CONCLUSIONS

Patients with isolated OTA/AO 44B fractures without MCS widening on initial injury radiographs did not demonstrate instability on subsequent weightbearing radiographs and had equivalent outcomes regardless of gravity stress radiography findings when treated nonoperatively. Weightbearing radiographs at the initial follow-up appear to be 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.

Effects of Progressive Deltoid Ligament Sectioning on Weber B Ankle Fracture Stability

BACKGROUND

Conventionally, transsyndesmotic fibula fractures with concomitant signs of deltoid ligament injury have been considered unstable and thus treated operatively. Recent studies have indicated that partial deltoid ligament rupture is common and may allow for nonoperative treatment of stress-unstable ankles if normal tibiotalar alignment is obtained in the weightbearing position. Biomechanical support for this principle is scarce. The purpose of this study was to evaluate the biomechanical effects of gradually increasing deltoid ligament injury in transsyndesmotic fibula fractures.

METHODS

Fifteen cadaveric ankle specimens were tested using an industrial robot. All specimens were tested in 4 states: native, SER2, SER4a, and SER4b models. Ankle stability was measured in lateral translation, valgus, and internal and external rotation stress in 3 talocrural joint positions: 20 degrees plantarflexion, neutral, and 10 degrees dorsiflexion. Talar shift and talar valgus tilt in the talocrural joint was measured using fluoroscopy.

RESULTS

In most tests, SER2 and SER4a models resulted in a small instability increase compared to native joints and thus were deemed stable according to our predefined margins. However, SER4a models were unstable when tested in the plantarflexed position and for external rotation in all positions. In contrast, SER4b models had large-magnitude instability in all directions and all tested positions and were thus deemed unstable.

CONCLUSION

This study demonstrated substantial increases in instability between the SER4a and SER4b states. This controlled cadaveric simulation suggests a significant ankle-stabilizing role of the deep posterior deltoid after oblique transsyndesmotic fibular fracture and transection of the superficial and anterior deep deltoid ligaments.

CLINICAL RELEVANCE

The study provides new insights into how the heterogenicity of deltoid ligament injuries can affect the natural stability of the ankle after Weber B fractures. These findings may be useful in developing more targeted and better treatment strategies.

Role of the posterior deep deltoid ligament in ankle fracture stability: A biomechanical cadaver study

BACKGROUND

The deltoid ligament is a key component of ankle fracture stability. Clinical tests to assess deltoid ligament injury have low specificity. In supination external-rotation (SER) type-IV ankle fractures, there is either a medial malleolus fracture or deltoid ligament injury. These injuries are often considered unstable, requiring surgical stabilisation. We look to identify the anatomical basis for this instability. This study investigates the anatomical basis for such instability by re-creating SER type ankle fractures in a standardised cadaveric study model, investigating the anatomical basis for such instability.

AIM

To investigate the anatomical basis for fracture instability in SER type ankle fractures.

METHODS

Four matched pairs of cadaveric limbs were tested for stability both when axially loaded and under external rotation stress. Four matched pairs of cadaveric limbs (8 specimens) were tested for stability when axially loaded to 750 N with a custom rig. Specimens were tested through increasing stages of SER injury in a stepwise fashion before restoring the lateral side with open reduction and internal fixation (ORIF). Clinical photographs and radiographs were recorded at each step. We defined instability in accordance with well accepted radiological parameters: > 4 mm medial clear space opening on a mortise-view radiograph or > 7 degrees of talar tilt.

RESULTS

All specimens with an intact posterior deep deltoid ligament were stable. Once the posterior deep deltoid ligament was sectioned there was instability in all specimens. Stabilisation of the lateral side prevented talar shift, but not talar tilt.

CONCLUSION

If the posterior deep deltoid ligament is intact then SER fractures can be managed without surgery. If the posterior deep deltoid is incompetent, ORIF and cautious rehabilitation is recommended because the talus can still tilt in the mortise.

Radiographic parameters of the normal ankle syndesmosis: Comparison between hindfoot alignment view and anteroposterior view

OBJECTIVE

To compare the parameters associated with the normal ankle syndesmosis between the hindfoot alignment view (HAV) and anteroposterior (AP) view and determine which view is more accurate for comparing the left and right ankles.

METHODS

This study involved 61 subjects without syndesmosis injury who had radiographs of both ankles. The tibiofibular clear space (TFCS), tibiofibular overlap (TFO), and medial clear space (MCS) were measured in each view. Intraclass correlation coefficients were used to assess the agreement between the two ankles. Difference ratios for the measured parameters between the ankles were also compared.

RESULTS

The agreement for TFCS showed wide disparity between the two ankles (AP view, 0.576; HAV, 0.858). The highest degree of agreement was seen for TFO (AP view, 0.733; HAV, 0.926). The agreement for MCS was low in both groups. The mean difference ratio for TFCS was also lower in the HAV group (9.9%) than in the AP view group (16.4%); a similar result was observed for TFO (16.4% vs. 25.8%).

CONCLUSIONS

For evaluation of the syndesmosis, use of the HAV showed increased accuracy and few measurement errors when comparing the left and right ankles relative to use of the AP view.

Arthroscopic Quantitative Measurement of Medial Clear Space for Deltoid Injury of the Ankle: A Cadaveric Comparative Study With Stress Radiography

BACKGROUND

The deltoid ligament (DL) is an important stabilizer of the ankle. DL injury of varying severity can occur alone or with syndesmotic injury and fibular fracture. Limited diagnostic tools are available to assess DL injury quantitatively.

PURPOSE

To establish an arthroscopic quantitative assessment of DL injury and to compare its performance with that of external rotation stress (ERS) and gravity stress (GS) radiography.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 24 cadaveric lower extremities were divided into 4 groups: group 1 consisted of intact DL, group 2 of superficial DL disruption, group 3 of deep DL disruption, and group 4 of complete DL (superficial and deep) disruption. All specimens underwent sequential sectioning of syndesmotic ligaments, and medial clear space (MCS) was measured with ankle arthroscopy, ERS radiography, and GS radiography at different stages of syndesmotic sectioning.

RESULTS

For noninjured deltoid (group 1) and injured deltoid (groups 2-4), area under the receiver operating characteristic curve (AUC) of measurement of MCS was 0.939 for arthroscopy, 0.932 for ERS radiography, and 0.874 for GS radiography, with a significant difference between arthroscopy and GS radiography (P = .014). For incomplete deltoid injury (groups 1-3) and complete deltoid injury (group 4), the AUC of MCS was 0.811 for arthroscopy, 0.656 for ERS radiography, and 0.721 for GS radiography, with a significant difference between arthroscopy and ERS radiography (P < .001) and between arthroscopy and GS radiography (P = .035). For all stages of syndesmotic sectioning, cutoff values of arthroscopic MCS with intact fibula were ≤2.5 mm for intact DL, between 2.5 and 3.5 mm for partial DL injury (superficial or deep), and ≥3.5 mm for complete DL injury. Arthroscopy was unable to detect a difference between superficial deltoid injury (group 2) and deep deltoid injury (group 3) in partial DL injury, with a measured MCS between 2.5 and 3.5 mm. The intraclass correlation coefficient of interrater reliability was 0.975 for arthroscopy, 0.917 for ERS radiography, and 0.811 for GS radiography.

CONCLUSION

Arthroscopic MCS measurement can differentiate intact DL, partial DL injury, and complete DL injury. Compared with ERS and GS radiography, arthroscopic MCS measurement has greater accuracy with excellent interrater reliability.

CLINICAL RELEVANCE

For patients with suspected DL injury, arthroscopic MCS is useful for determining deltoid lesion severity based on defined cutoff values for consideration in preoperative planning to improve surgical outcomes.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

DISCUSSION

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.

LEVELS OF EVIDENCE

Diagnostic studies-investigating a diagnostic test: Level III.

The Value of Additional Gravity Stress Radiographs for Decision Making in the Treatment of Isolated Type B Distal Fibular Fractures

BACKGROUND

Prior to treatment decisions concerning isolated Weber type B ankle fractures, assessment of the stability of the ankle joint is mandatory. The gravity stress (GS) radiograph is a radiographic tool to determine stability. We hypothesized that this additional GS radiograph would lead to fewer operative treatments by applying the criterion of operative treatment when medial clear space (MCS) > superior clear space (SCS) + 2 mm on the GS radiograph, compared with the nonstressed mortise view criteria of advising operative treatment in case of MCS > SCS + 1 mm.

METHODS

This retrospective comparative cohort study analyzed 343 patients aged between 18 and 70 years with an isolated Weber type B ankle fracture diagnosed at the emergency department between January 2014 and December 2019. The cohort was divided into 2 groups based on whether an additional GS radiograph was performed. Group I consisted of 151 patients in whom a regular mortise and lateral radiograph were performed. Group II comprised 192 patients, with an additional GS radiograph. Primary outcome was type of treatment (conservative vs operative). Secondary outcomes were patient-reported functional outcomes and pain.

RESULTS

Baseline characteristics of both groups did not differ. In group I, surgery was performed in 60 patients (39.7%) compared with 108 patients (56.3%) in group II (P = .002). In the operatively treated patients, the mean MCS on regular mortise view was significantly smaller in patients in whom an additional GS radiograph was performed compared to patients without an additional GS radiograph (4.1 mm vs 5.2 mm, P < .001). Mean Olerud-Molander Ankle Score and mean visual analog scale (VAS) for pain did not differ significantly between groups I and II.

CONCLUSIONS

Contrary to what was hypothesized, the introduction of an additional gravity stress radiograph, by which operative treatment was indicated if the MCS was wider than the SCS + 2 mm, did not result in reduced operative treatment of Weber type B ankle fractures when operative treatment was indicated for MCS > SCS + 1 mm on non-gravity stress radiographs.

LEVEL OF EVIDENCE

Level III: retrospective comparative study.

State of the Art in Treatment of Chronic Medial Ankle Instability

Chronic deltoid instability (CDI), or medial ankle instability, can happen following traumas of the foot and ankle, predominantly rotational injuries. CDI is frequently underdiagnosed or misdiagnosed. Long-term residual instability can lead to ankle posttraumatic arthritis. Adequate assessment of patients with suspected CDI is paramount. Conservative treatment can be tried for stable or mildly unstable cases, but surgical treatment is usually needed for the more severely unstable patients, or when conservative measures fail. Few reconstruction techniques have been proposed in the setting of posttraumatic CDI. This article describes our preferred technique for reconstruction of the deep components of the deltoid ligament.

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.

Therapeutic approach to combined deltoid ligament disruption with lateral malleolus fracture: Current evidence and literature review

Ankle fractures are among the most common injuries treated by orthopaedic traumatologists. These fractures range from stable, simple injuries to complex, multi-planar unstable ones. Osseo-ligamentous structures play a paramount role in maintaining the stability of the ankle joint. The deltoid ligament is among the most important ankle static stabilizers. Rupture of this ligament along with a lateral malleolar fracture is considered by many as an unstable type of injury and usually requires surgical treatment (bi-malleolar equivalent). Left untreated, it may lead to chronic pain, loss of function and secondary arthritis. Due to lack of high-quality evidence, there are no welldefined, well-accepted criteria for the diagnosis and treatment for treating this type of injury.

Combined Posteromedial and Posterolateral Approaches for 2-Part Posterior Malleolar Fracture Fixation

BACKGROUND

This study investigated the clinical efficacy of combined posteromedial and posterolateral approaches for repair of 2-part posterior malleolar fractures associated with medial and lateral malleolar fractures.

METHODS

This case series report included 27 Weber B with Haraguchi type II patients with medial and lateral malleolar fractures combined with 2-part posterior malleolar fractures. Patients were treated with open reduction and internal fixation through a combination of posteromedial and posterolateral approaches from January 2015 to January 2018. There were 11 males and 16 females, with an average age of 61.5 years (range, 53-67 years). The procedures were performed on prone patients under spinal anesthesia. The medial, lateral, and posterior malleolar fractures were exposed through posteromedial and posterolateral approaches performed at the same time. The lateral malleolar fracture was fixed using a plate, the medial malleolar fracture was fixed using screws, and the posterior malleolar fracture was fixed using a plate or cannulated screws according to the size of the fragments. We performed follow-up on 22 patients for an average of 30 months (range, 18-48 months).

RESULTS

Primary healing of the incisions was achieved in all cases, and no infection was found. The mean time of bone union was 12.5 weeks (range, 10-15 weeks). The mean time from the operation to full weightbearing was 13 weeks (range, 11-16 weeks). We used the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale to score patient outcomes; the mean score was 85.4 (range, 80-92) at the final follow-up. No significant pain was found at the final follow-up.

CONCLUSION

This study showed that satisfactory outcomes were achieved with combined posteromedial and posterolateral approaches. Therefore, we believe this approach was a good alternative strategy to repair 2-part posterior malleolar fractures associated with medial and lateral malleolar fractures.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Management of Isolated Lateral Malleolus Fractures

Isolated lateral malleolus fractures represent one of the most common injuries encountered by orthopaedic surgeons. Nevertheless, appropriate diagnosis and management of these injuries are not clearly understood. Ankle stability is maintained by ligamentous and bony anatomy. The deep deltoid ligament is considered the primary stabilizer of the ankle. In the setting of an isolated lateral malleolus fracture, identifying injury to this ligament and associated ankle instability influences management. The most effective methods for assessing tibiotalar instability include stress and weight-bearing radiographs. Clinical examination findings are important but less reliable. Advanced imaging may not be accurate for guiding management. If the ankle is stable, nonsurgical management produces excellent outcomes. In the case that clinical/radiographic findings are indicative of ankle instability, surgical fixation options include lateral or posterolateral plating or intramedullary fixation. Locking plates and small or minifragment fixation are important adjuncts for the surgeon to consider based on individual patient needs.

Compatibility of Lauge-Hansen Classification Between Plain Radiographs and Magnetic Resonance Imaging in Ankle Fractures

We evaluated the accuracy of the predictive injury sequences of the Lauge-Hansen (L-H) classification using magnetic resonance imaging (MRI) in patients with ankle fractures and determined the possible causes of mismatch. Sixty-five patients with ankle fractures who had a complete series of anteroposterior, lateral, and oblique radiographs and ankle MRI studies available were included. The fracture pattern was assigned by 2 senior orthopedic surgeons according to the L-H classification system. The syndesmotic ligaments, lateral collateral ligaments, and medial deltoid complex ligaments were evaluated on the preoperative MRI scans. Comparisons were performed between the predicted ankle ligamentous injury based on the radiographic L-H classification and preoperative MRI analysis. Of the 65 feet in 65 patients, 50 feet (76.9%) were classified as having a supination-external rotation (SER) fracture, 6 feet (9.2%) as having a pronation-external rotation fracture, 4 feet (6.2%) as having a supination adduction fracture, and 2 feet (3.1%) as having a pronation abduction fracture. The overall compatibility of the radiologic classification with the MRI classification was 66.1%. In the evaluation of 50 feet with the MRI SER designation, maximum compatibility was found for stage 4 (77.3%). The main cause for the discrepancy in the SER designation was missing the presence of deltoid ligament disruption on the plain radiographs, especially in the stage 2 and 3 SER fracture pattern. In the evaluation of deltoid complex injuries, all injuries were localized to the anterior part of the medial deltoid complex. The validity of the L-H classification system was low. A new classification system is needed to address the medial malleolus fracture or deltoid complex injuries without posterior injury. Also, stress radiographs could be added to standard radiographs for the classification to address deltoid complex injuries.