Deep Deltoid Ligament Research Articles

Distal Tibiofibular Syndesmosis Injuries in the National Football League (NFL): A Spectrum of Pathology That Correlates With Time to Return to Full Participation.

Studies routinely evaluate high ankle sprains in isolation, but recent data suggest that these injuries are often associated with concomitant pathology, potentially influencing return to full participation. In National Football League (NFL) players, isolated high ankle sprains are rare and syndesmosis injuries with concomitant pathology will result in increased time to return to full participation. Cross-sectional study. Level 3. Distal tibiofibular syndesmosis injuries sustained by NFL players between 2017 and 2019 were identified through NFL Injury Surveillance Database queries and verified with video analysis. Each injury underwent a comprehensive magnetic resonance imaging (MRI) review. Regression modeling was utilized to explore the influence of numerous imaging findings on time to return to full participation. There were 83 external rotation ankle injuries involving the syndesmosis. Isolated distal tibiofibular syndesmosis injuries were rare (n = 11; 13%) and more often associated with other ligamentous injury (deltoid ligament and lateral ligamentous complex) and/or fractures. Regression modeling resulted in clustering of 3 injury pattern groups for time to return to full participation across numerous imaging findings: syndesmosis injury-fracture combinations (250 days [interquartile range [IQR,] 142-266 days]), syndesmosis injury with complete deep deltoid tear or acute diastasis (175 days [IQR, 20-248 days]), and all other syndesmosis injuries (27 days [IQR, 18-46 days]). In NFL athletes with external rotation ankle injuries, isolated distal tibiofibular syndesmosis injuries were rare and more often associated with concomitant pathology. Time to return to full participation was affected by an associated fracture and complete deep deltoid ligament tear or diastasis but no other relevant MRI variables such as lateral ligament complex involvement or the presence of osteochondral lesions or bone contusions.

Functional Anatomy of the Rear Attachment of the Deep Deltoid (RAD) Ligament of the Ankle.

The deltoid ligament plays a key role in ankle stability. Ankle fractures involving the medial ligamentous complex are evaluated on the basis of medial-sided tenderness and the Ottawa ankle rules. Evolution in our understanding of this ligament over the last three decades has shown that, within this medial ligamentous complex, it is the deep deltoid ligament that confers mechanical stability. The latest evolution in this understanding, and the learning point of this report, is that only a distinct component of the deep deltoid ligament - specifically the discreet posterior third - the rear attachment of the deep deltoid ligament (RAD) - confers mechanical value. The RAD is responsible for providing the medial ligamentous component of ankle stability - specifically talar shift, tilt, and importantly rotational stability. This knowledge is of key importance in the assessment and management of ankle fractures with associated deltoid ligament injuries. In this technical report, we highlight the biomechanical contribution of the RAD, which will help surgeons and physiotherapists to accurately manage ankle injuries.

Arthroscopic repair of the tibiotalar fascicle of deltoid ligament is feasible through anterior ankle arthroscopy.

Although arthroscopic repair of the deltoid ligament is becoming a popular procedure, no studies have assessed which bundles of the deltoid ligament can be reached by anterior ankle arthroscopy. This study aimed to assess the feasibility of the arthroscopic repair of the deep layer of the deltoid ligament. In addition, it aimed to correlate which fascicle of the superficial layer of the deltoid ligament corresponds to the deep fascicle visualised by arthroscopy. Arthroscopy was performed in 12 fresh frozen ankles by two foot and ankle surgeons. With the arthroscope introduced through the anterolateral portal, the medial compartment and the deltoid ligament were explored in ankle dorsiflexion without distraction. Using a suture passer introduced percutaneously, the most posterior fibres of the deep deltoid ligament visualised by anterior arthroscopy were tagged. Then, the ankles were dissected to identify the deep and superficial bundles of the deltoid ligament tagged with a suture. In all specimens (100%), the intermediate part of the tibiotalar fascicle, corresponding to the fibres originating from the anterior colliculus, was tagged with a suture. The posterior part of the tibiotalar fascicle was never tagged with a suture. In all specimens, the intermediate part of the tibiotalar fascicle grasped by the suture correlated with the tibiospring fascicle of the superficial layer. The current study demonstrates the feasibility of the arthroscopic repair of the deep fascicle of the deltoid ligament. By performing anterior arthroscopy, it is possible to visualise and repair the intermediate part of the tibiotalar fascicle (deep layer of the deltoid ligament). These fibres correspond to the tibiospring fascicle of the superficial layer. The clinical relevance of the current study is that the arthroscopic repair of the deep layer of the deltoid ligament is feasible through anterior ankle arthroscopy. Not applicable.

Biomechanical Effects of Hindfoot Alignment in Supination External Rotation Malleolar Fractures: A Human Cadaveric Model.

Pressure distribution in the ankle joint is known to be dependent on various factors, including hindfoot alignment. We seek to evaluate how hindfoot alignment affects contact pressures in the ankle joint in the setting of supination external rotation (SER) type ankle fractures. SER fractures were created in 10 human cadaver lower extremity specimens, simulating progressive stages of injury: without fracture (step 0), SER fracture and intact deltoid ligament (step 1), superficial deltoid ligament disruption (step 2), and deep deltoid ligament disruption (step 3). At each step, varus and valgus alignment was simulated by displacing the calcaneal tuberosity 7 mm medial or lateral. Each limb was axially loaded following each osteotomy at a static load of 350 N. The center of force (COF), contact area (CA), and peak contact pressure (PP) under load were measured, and radiographs of the ankle mortise were taken to analyze the medial clear space (MCS) and talar tilt (TT). The COF (5.3 mm, P = .030) and the CA (-188.4 mm2, P = .015) changed in step 3 in the valgus hindfoot alignment compared to baseline parameters, indicating the importance of deep deltoid ligament integrity in maintaining normal ankle joint contact stress in the valgus hindfoot. These changes were not seen in the setting of varus alignment (COF: 2.3 mm, P = .059; CA -121 mm2, P = .133). PP were found to not change significantly in either varus or valgus (varus: -4.9 N, P = .132; valgus: -4 N, P = .464).The MCS demonstrated widening in step 3 compared to step 2 (0.7 mm, P = .020) in both varus and valgus hindfoot. The TT increased significantly in step 3 in the valgus hindfoot (2.8 degrees, P = .020) compared to step 0. SER-IV fractures with valgus hindfoot alignment showed significant changes in pressure distribution and radiographic parameters when compared to SER-IV fractures with varus hindfoot alignment. Based on this cadaver modeling study, patients with SERIV fracture with varus hindfoot alignment and complete deltoid ligament lesion may not need fracture fixation, whereas those with valgus hindfoot alignment likely need fracture fixation.

The additional value of weight-bearing radiographs in assessing stability of isolated type B fibular fractures

IntroductionIn isolated type B fibular fractures, the decision whether to operate or treat conservatively is principally based on congruency and stability of the ankle joint. The purpose of the current study is to examine the additional diagnostic value of the weight-bearing radiograph (WBR) in assessing stability of potentially unstable type B fibular fractures. Materials and MethodsIn this retrospective cohort study, patients were selected based on who presented an isolated type B fracture of the fibula. Unstable fractures were directly planned for surgery. Other patients underwent additional weight-bearing imaging 4–7 days after initial trauma, on which definitive treatment was based. The medial clear space (MCS) was compared between the WBR and the conventional radiograph. ResultsA total of 70 patients were included in the period January 2018-December 2021. The average MCS on conventional mortise radiograph was 3.56 mm compared to 3.02 mm on the WBR(p<0.05). The superior clear space (SCS) was equal between both groups (respectively 3.12 mm and 3.08 mm, p = 0.44). All 70 patients were initially treated conservatively with immediate weight-bearing in a brace or soft cast. One patient had the need for open repair and internal fixation due to non-union. DiscussionDifferent techniques for the assessment of deep deltoid ligament integrity exist, such as the MRI, the ultrasonography and different kinds of stress test radiographs. As fractured ankles don't need direct fixation and operative treatment can be postponed, a stepped approach for the assessment of deep deltoid ligament (DDL) integrity can be of assistance in assessing ankle stability. In isolated type B fibular fractures a stepped approach, using the weight-bearing radiograph can be of additional value in assessing the stability. It is a low cost, prevents unnecessary surgery and contributes to a quick weight-bearing non-operative treatment.

Repair of deep deltoid ligament ruptures near the medial malleolar attachment or midsubstance rupture by using suture anchors into the talus combined with the transosseous suture in the medial malleolar.

For deep deltoid ligament ruptures near the medial malleolar attachment, anchors were usually placed at the posterior colliculus and intercollicular groove. However, this procedure usually requires a prolonged surgical incision to fully expose the deep deltoid ligament, causing more trauma. In order to reduce surgical trauma, we explored the treatment outcomes of suture anchor into the talus combined with transosseous suture in the medial malleolar for the treatment of deep deltoid ligament ruptures near the medial malleolar attachment or midsubstance rupture. This is a retrospective study of patients who received suture anchor into the talus combined with transosseous suture in the medial malleolar for repairing deltoid ligament ruptures near the medial malleolar attachment or midsubstance rupture. The outcome measures include the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, visual analogue scale (VAS), and the active range of motion (ROM) of the ankle at the final follow-up visit after surgery. Medial malleolus gap was evaluated by radiographic examination. This study included 64 patients. The mean follow-up time was 36.3 ± 15.2 months. There were 43 patients with injuries on the medial malleolar side, and 21 cases on the midsubstance. The average AOFAS and VAS were 87.5 ± 4.9 and 0.7 ± 0.5, respectively. No significance in medial malleolus gap between the contralateral side and affected side was observed. For deltoid ligament ruptures near the medial malleolar attachment or midsubstance rupture, suture anchor into the talus combined with transosseous suture in the medial malleolar yields good clinical effect and outcome, is an optimal management of ankle syndesmosis injuries.

Open Ankle Dislocation Without Associated Malleolar Fracture: Case Report

Open pure tibiotalar dislocations are rarely recorded cases with superficial fibular nerve damage. Case presentation: The authors describe a case of open tibiotalar dislocation without a fracture and a deep deltoid ligament damage as a result of a bad fall. Six hours after the trauma, debridement, open reduction, and casting were done. Following a 4-week checkup, the results were positive and infection-free. Conclusion: Early reduction and appropriate wound care of an open tibiotalar dislocation with delayed repair of an associated deep deltoid ligament tear led to a successful outcome.

Deep Deltoid Ligament Reconstruction Utilizing Suture Augmentation via an Arthroscopically- Assisted Approach: A Novel Technique and Case Series

Category: Trauma; Arthroscopy Introduction/Purpose: Deltoid ligament rupture is a common occurrence in the setting of acute ankle fractures. The indications for surgical restoration of the deltoid ligament complex vary considerably throughout the literature. If medial ankle instability exists after ankle fracture fixation, repair or reconstruction of the deltoid ligament complex may be performed, which is traditionally done via an open approach. While the superficial deltoid is easily accessed with an open approach, the deep deltoid ligament is extremely difficult to visualize. We present a novel technique for reconstruction of the deep deltoid ligament complex utilizing suture augmentation via an arthroscopically-assisted approach and present our outcomes. With this method, the deep deltoid ligament disruption is easily visualized and reconstructed in a minimally invasive manner through an accessory anteromedial arthroscopy portal. Methods: This is a technique guide and retrospective case series. Data was obtained via chart review including pre-operative, intraoperative, and post-operative follow ups. Variables such as age, weight, body mass index (BMI), sex, side, history of previous ankle surgery, preoperative ambulatory status, length of hospital stay, as well as disposition were documented. Radiographs were reviewed for evidence of restoration of the medial clear space as well as hardware position and bony union. In addition, a technique guide was developed using expert surgeon experience and opinion while using this novel technique. Results: 7 patients who underwent this novel technique were reviewed with an average follow up time of six months (3-8 months). All patients suffered bimalleolar or trimalleolar equivalent fractures. Patients were indicated for deep deltoid ligament reconstruction if medial ankle instability existed intraoperatively with valgus stress testing under fluoroscopy. Medial clear space decreased from a mean 11mm preoperatively to 3.3mm postoperatively. 6 patients returned to ambulation without brace by three months postoperatively. One patient demonstrated increased medial clear space measured at 6.6mm postoperatively and residual pain on follow up, but was treated conservatively and able to progress to weight bearing as tolerated by 6 months. One patient developed a keloid scar that required a steroid injection. No postoperative infections occurred. Conclusion: Deep deltoid ligament reconstruction utilizing suture augmentation via an arthroscopically-assisted approach should be considered in patients who have residual medial ankle instability after ankle fracture fixation. This novel technique allows visualization of the deep deltoid ligament complex and reconstruction in a minimally invasive manner via an accessory anteromedial arthroscopy portal. Our short term outcomes demonstrate success in restoring ankle function and radiographic parameters of the medial clear space. Further studies are needed to evaluate long term postoperative functional outcomes, stability, and development of post-traumatic arthritis.

The Impact of Tendon Lengthening Following Achilles Tendon Repair on Foot Kinetics, a Finite Element Analysis

Category: Midfoot/Forefoot; Hindfoot Introduction/Purpose: Triceps surae muscle force is transferred through the Achilles tendon to the calcaneus and from the calcaneus to the plantar fascia and then to the metatarsal heads and the toes which exert force on the ground. Achilles tendon ruptures occur in tendons that have reached a critical point of intrasubstance degeneration. The Achilles tendon almost always heals but frequently lengthens during the healing process, leading to an alteration in the triceps surae force production profile. We hypothesized that Achilles tendon overlengthening has implications not only for force generation but likely has many other impacts throughout the foot. The goal of this work was to evaluate the effect of a lengthened Achilles tendon following tendon repair on the kinetics of the foot. Methods: A validated finite element model of the foot was used to compare foot biomechanics between the foot with a functional and non-functional Achilles tendon. The model of the foot constructed from CT scan images of a female cadaveric foot weighing 60 kg included all 28 bones, 72 ligaments, cartilage, and an encapsulating soft tissue. The model was loaded with 0.5 body weight applied at the center of mass and 0.25 body weight applied to the Achilles tendon simulating quiet stance. The tendon forces were applied using force vectors in the direction of their lines of action. The foot with a non-functional Achilles tendon was created by unloading the Achilles tendon since triceps surae muscle shortening due to tendon lengthening significantly decreases force production. The force transmitted through the joints, force in the ligaments, and plantar pressure were determined for both the foot with a functional and non-functional Achilles tendon. Results: We found that the force transmitted through all the joints decreased when the Achilles tendon force was removed (Figure 1a). In addition, removing the Achilles tendon decreased the force within the plantar fascia, long and short plantar ligaments, and deep deltoid ligament, while it increased the force within the spring and superficial deltoid ligaments (Figure 1b). The plantar fascia experienced the greatest reduction in ligament force after unloading of the Achilles tendon (from 93 N to 26 N). Moreover, the maximum plantar pressure in the heel fat pad increased from 164 kPa to 231 kPa when the Achilles tendon was removed. Conclusion: The varying changes in the force in the ligaments and joints due to Achilles lengthening suggest that Achilles tendon rupture with sequent healing with overlengthening can alter the force distribution throughout the entire foot. A major implication of this work is that in treating Achilles ruptures, an extended period of protection with heel wedges beyond the customary six weeks may be needed to prevent over lengthening of the Achilles. Moreover, this study supports the efficiency of surgical lengthening of the Achilles in the treatment of diabetic forefoot foot ulcers by shifting the plantar pressure towards the calcaneus.

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

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. To investigate the anatomical basis for fracture instability in SER type ankle fractures. 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. 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. 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 foot alignment and morphological features of deltoid ligament in pediatric patients with medial osteochondral lesions of the talus.

The cause of osteochondral lesions of the talus (OLT) in patients without a history of trauma remains unclear, and almost all nontraumatic lesions appear to involve the medial talar dome. This study aimed to investigate the relationship between foot alignment, deltoid morphology, and medial OLT in pediatric patients. In total, 28 patients (31 feet) with medial OLT (17 boys, 11 girls, mean age: 14.9 years), and 50 patients without OLT (50 feet, 31 boys, 19 girls, mean age: 14.5 years) were included in this study. The OLT patients were subdivided into traumatic and nontraumatic groups. Radiographic parameters of the foot arch were measured on weight-bearing lateral images. The extent of the OLT was measured on computed tomographic images. The ratio of deep deltoid attachment length of the talus to talar height was examined as deltoid ligament position index (DPI) on coronal magnetic resonance imaging. Nontraumatic medial lesions were frequently observed in pediatric patients (54.8%) compared to traumatic lesions. The depression of the foot arch was commonly identified in pediatric patients with resistant medial lesions. The lesion size was moderately correlated with DPI (rho = 0.48; P = 0.0086). The attachment of the deep deltoid ligament to the medial talar dome was located more proximally in nontraumatic lesions than in traumatic lesions and the control group. Our findings suggest that a combination of foot alignment and the anatomic variations in the attachment of the deep deltoid ligament contributes to the incidence of nontraumatic medial OLT in the pediatric population. Level of evidence: level IV.

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.

MRI Findings in Patients with Discordant Results Between Gravity Test and Weight-Bearing Stress Views in Isolated Supination-External Rotation Fibular Fracture

Category: Trauma Introduction/Purpose: Medial and syndesmotic stability evaluation of isolated supination-external rotation fibula fractures (ISER) is critical to determine surgical conduct. However, there is no agreement on the best method to diagnose instability preoperatively. This problem is especially relevant in those with less than 2mm displacement in non-weightbearing radiographs. Different radiographic stress methods have been proposed: external rotation, weightbearing x-rays (WBx), and gravity stress radiographs (GSx). Likewise, the literature describes the use of ultrasound and magnetic resonance imaging (MRI) as complementary studies. To our knowledge, no studies have described the MRI findings in patients with discordant results between GSx and WBx views. Purpose: To analyze the imaging findings in WBx, GSx, and MRI in a consecutive group of patients with ISER with discordant results on stress views. Methods: For two years and prospectively, consecutive patients treated in a Level 1 trauma center were enrolled, performing the following imaging study protocol:- All patients with ISER fractures with a congruent tibiotalar joint on non-weightbearing radiographs underwent a bilateral WBx and GSx.- When there was a discordant result between WBx and GSx, MRI was taken. A retrospective analysis of the patients who had a complete study was carried out, considering the radiological findings and measurements. Measurements on radiographs were performed by six physicians (2 general practitioners, two trauma residents, and two ankle and foot subspecialists). One musculoskeletal radiologist analyzed the MRIs. The following parameters were measured, medial clear space (MCS), superior clear space (SCS), and tibiofibular clear space (TFCS). Inter-observer agreement in radiographs was analyzed using the intra-class correlation coefficient. Differences between groups were evaluated by t-student for independent samples, considering α &lt;=5% significant. Results: Thirty-four patients were recruited. Interobserver agreement was good to excellent on all radiographic measurements. For all the measurements in the WBx, there were no significant differences between the injured and the healthy side. Average of MCS 2.51, SCS 3.07 and TFCS 3.74 mm for the uninjured side; and MCS 2.51, SCS 3.12, and TFCS 3.67 mm for the injured side. In the GSx, significant differences were observed for all measurements between the fractured and the healthy side. Average of MCS 3.55, SCS 3.85, and TFCS 3.89 for the healthy side; and MCS 5.87, SCS 4.25, and TFCS 4.44 for the injured side.100% of GSx and 0% of WBx met instability criteria (more than 2 mm compared to the healthy side). None of the MRIs showed a complete lesion of the deep deltoid ligament nor syndesmal complex. Conclusion: MRI did not demonstrate a complete deltoid nor syndesmal lesion in any patient with ISER fracture with normal WBx and altered GSx. A positive GSx does not correlate with MRI findings in patients with a non-displaced WBx study.

Endoscopic Posterior Ankle Decompression and Release After Total Ankle Arthroplasty

Accurate positioning of the total ankle arthroplasty implant components with the absence of any hindfoot deformity does not preclude the development of bony impingement. In cases of ankle stiffness after total ankle arthroplasty, the usual limitation is in dorsiflexion. If triceps surae contracture is excluded or persistent restriction remains in ankle dorsiflexion after gastrocnemius recession or tendo-Achilles lengthening, posterior ankle capsulectomy, debridement of posterior ankle gutter, and release of the deep posterior deltoid ligament and the posterior talofibular ligament are indicated. In this Technical Note, the technical details of endoscopic posterior ankle decompression and release after total ankle arthroplasty are described.

Superficial Deltoid Ligament and Deep Deltoid Ligament Play Equally Important Roles in the Stability of Isolated Lateral Malleolus (OTA/AO 44-B1) Fractures: A Biomechanical Study

To evaluate the individual contributions to stability of the superficial and deep deltoid ligaments in the setting of SER IV ankle fractures. Nineteen total cadaveric specimens were used. SER IV injuries were created with the rupture of either the superficial (SER IV-S) (n = 9) or deep deltoid (SER IV-D) (n = 10). These were tested by applying an external rotation force (1 Nm, 2 Nm, 3 Nm, and 4 Nm). Changes in the position of the talus were recorded with a 3D motion tracker. Injury conditions were compared with a 4-step general linear model with repeated measures. Injury condition was also compared with the intact state and to each other using 2-tailed t tests. The general linear model showed that increased loading had a significant effect with axial rotation (P = 0.02) and sagittal translation (P = 0.003). SER IV-S and SER IV-D showed significantly greater instability compared with the intact state in axial rotation (1 Nm, 2 Nm, and 3 Nm). SER IV-S and SER IV-D did not significantly differ from each other. SER IV fracture patterns can be unstable with isolated injury to either the superficial or deep deltoid. This challenges the notion that deep deltoid rupture is necessary. Further clinical studies would help quantify the consequences of this instability.

A Biomechanical Investigation on the Effects of Deep Deltoid Ligament Repair Combined with Flexible and Rigid Syndesmotic Fixation

Category:Ankle; TraumaIntroduction/Purpose:The role of deep deltoid ligament (DDL) repair in the setting of an unstable syndesmotic injury is largely unknown, and the optimal fixation strategy for syndesmosis stabilization is controversial. The purpose of this study was to investigate the effect of an augmented, anatomic repair of the DDL combined with flexible or rigid syndesmotic stabilization using a cadaveric model.Methods:10 pairs of fresh-frozen through knee cadaveric specimens were used for biomechanical testing which included subjecting the specimens to 5 Nm of external rotation torque while under 750 N of axial compression. Whole-foot rotation angles were measured and rotation and translation of the fibula, tibia, and talus were tracked with optical motion capture. Specimens were tested intact and then after destabilization by sectioning the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament, interosseous ligament and membrane extending 7 cm proximal to the ankle joint, and both bands of DDL. The intact fibula was a surrogate for an anatomically fixed fibula. Each specimen underwent mechanical testing both with and without DDL reconstruction added to flexible syndesmotic stabilization using a suture button (SB) plus AITFL reconstruction. In the final test, the syndesmosis was rigidly stabilized using a 4.5 mm screw.Results:Destabilization increased the foot rotation under the applied axial load and torque to 170% (+-49%) of that of the intact case. After flexible syndesmotic stabilization (AITFL + SB) foot rotation was 109% (+-26%) of intact condition. Addition of the deltoid ligament reconstruction (AITFL + SB + DD) reduced rotation to 87% (+-31%) of the intact condition. Fixation with a screw alone came closest to the rotation of the intact specimen (93% +- 17% of intact), and like the flexible repair, the addition of DDL reconstruction to the screw increased rotational stability (85% +- 35% of intact).Conclusion:DDL reconstruction provides improved resistance to external rotation stress when added to both flexible and rigid syndesmotic stabilization. Although our results with both the flexible and rigid constructs demonstrated increased constraint to external rotation stress compared to the intact specimen, these results should be thought of as time zero data, and the implants likely experience some creep with early motion and graduated weight bearing. Our demonstration of increased stability with a deltoid ligament reconstruction suggests that this addition may be beneficial for unstable syndesmotic injuries.

Dynamic Portable Ultrasound Cutoff Values for Diagnosing Medial Ankle Instability in Supination External Rotation Ankle Injury: A Cadaveric Study

Category:Ankle; TraumaIntroduction/Purpose:In the setting of an isolated lateral malleolar fracture, stability is predicated by whether the deep deltoid ligament is intact. Portable ultrasound (P-US) has also been used in the clinical setting, allowing dynamic and non-invasive evaluation at the point of care. This study aimed to determine the cutoff values, as well as its sensitivity and specificity for diagnosing supination external rotation (SER) ankle injury stage IVb (with complete deltoid ligament rupture) using the P-US.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. The P-US measurement of the MCS was assessed by placing the ultrasound probe perpendicularly to the medial gutter at the anteromedial aspect and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. To determine the sensitivity and specificity of the diagnosis of SER injury type IV using the P-US, a receiver operating characteristic (ROC) curve analysis was performed.Results:The MCS optimal cutoff point to distinguish SER ankle injury stage IVb from other injury stages ranged from 10.4 to 13.8 during the GST, 4.2 to 7.9mm during the weight-bearing stress, and 10.6-17.9mm during the external rotation stress test (Table 1). All P-US cutoff values provided acceptable sensitivity (60-100%), specificity (84-100%), and the area under ROC curve (0.8-1.0) for diagnosing SER ankle injury stage IVb.Conclusion:MCS cutoff points assessed with the P-US under the GST, weight-bearing, and the external rotation stress test demonstrate high sensitivity and specificity for detecting SER ankle injury stage IVb. The cutoff values vary depending on which loading condition is being used. Additional clinical studies are necessary in the in vivo setting to better understand the implications of these test conditions.

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.

A Comparison of Portable Ultrasonography and the Fluoroscopy for Evaluating Medial Ankle Instability: A Cadaveric Study

Category:Ankle; TraumaIntroduction/Purpose:Diagnosis of destabilizing deltoid ligament injuries remains challenging and is best identified with dynamic imaging techniques. This study aims to assess and compare medial clear space (MCS) distances in various stages of sequentially created supination external rotation (SER) ankle injury model using portable ultrasound (P-US) and fluoroscopy. We hypothesize that there is a strong correlation between the P-US and fluoroscopic measurements for the assessment of medial ankle instability in SER type ankle injury during the gravity stress test (GST), weight-bearing, or external rotation stress test.Methods:Ten cadaveric specimens were used for assessing medial ankle instability. The assessment was performed with all structures intact, and later with sequential transection of the anterior inferior tibiofibular ligament (Stage I), fibular (Weber-B fracture) (Stage II), posterior inferior tibiofibular ligament (Stage III), superficial deltoid ligament (Stage IVa), and deep deltoid ligament (Stage IVb). In all scenarios, the GST, external rotation stress test(45N), and Simulated weight-bearing condition(750N) were performed. The P-US measurement of the MCS was assessed at the anteromedial and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. The fluoroscopic MCS measurements were assessed on a true mortise ankle view achieved during each loading condition. Spearman rank correlation was used to investigate the relationship between the P-US and fluoroscopic measurements. The inter- and intra-observer agreement was assessed using the intraclass correlation coefficient (ICC) through a two-way mixed-effects model with absolute agreement.Results:The P-US and fluoroscopic assessed medial ankle instability values during the GST, weight-bearing, and the external rotation stress test increased as the SER ankle injury stage progressed. The P-US values measured during all stress tests demonstrated a moderate to strong positive correlation with those measured with the fluoroscopy (Spearman's rank correlation ranged from 0.61-0.93, p-values <0.001). Inter-rater (P-US: 0.97, 95%CI: 0.96-0.98) and intra-rater reliability (P-US, 0.95, 95%CI: 0.94-0.96) for the P-US measurements were all substantial.Conclusion:The use of dynamic P-US to measure the MCS appears to be a reliable and repeatable technique. The P-US MCS measurement values measured in the SER ankle injury model during the GST, weight-bearing and the external rotation stress test are well correlated with those values measured with fluoroscopy. Therefore, the dynamic P-US with stress examination of the ankle has the potential to quantify medial ankle instability in a radiation-free, non-invasive, low cost, and point of care setting.

Is Repair of the Superficial Deltoid Ligament Alone Enough to Restore Medial Ankle Stability in Deltoid Ligament Injuries? A Cadaveric Study

Category:TraumaIntroduction/Purpose:Deltoid ligament injuries are controversial in many aspects: the best method to assess the stability of a Weber B fibular fracture, the indications of deltoid repair after lateral side surgical fixation, the best technique of deltoid repair and the efficacy of superficial deltoid repair alone, compared to repair of both deep and superficial deltoid ligaments, to restore medial ankle stability. The last point is specifically important because of the technical difficulty of repairing the deep deltoid ligament, specially if performed after fixation of the fibular fracture and the syndesmosis, which is the common scenario. The aim of the study was to evaluate the ability of superficial deltoid repair without deep deltoid repair to restore medial ankle stability in cases of deltoid ligament injuries.Methods:Ten fresh frozen ankle cadaveric specimens were used. Anteromedial dissection was performed to expose the ankle joint and to visualize the deltoid ligament. After good exposure, stress valgus and stress external rotation tests were performed with observation of the medial gutter and the medial part of the ankle joint for any widening. In all specimens, the ankle was stable at this point. Then, the superficial deltoid ligament was detached by sharp dissection from the medial malleolus followed by transection of the deep deltoid ligament completely at its midportion. Stress valgus and stress external rotation tests were repeated to demonstrate the gross instability of the ankle joint. Then, the superficial deltoid ligament was repaired using a suture anchor to the medial malleolus without any repair of the deep deltoid ligament. Then, stress valgus and stress external rotation tests were performed again to assess the medial ankle stability.Results:All ankles were stable initially as confirmed by stress valgus and stress external rotation tests. After cutting both components of the deltoid ligament, the ankles were found to be grossly unstable using the same tests. After repair of the superficial deltoid, all ankles were stable again with a medial space equal to the initial status and with negative stress valgus and stress external rotation tests.Conclusion:Surgical repair of the superficial deltoid ligament without repair of the deep deltoid ligament in cases of deltoid ligament injury may be sufficient to restore medial ankle stability. Limitations of the study include that all potential secondary restraints are intact in the cadaveric study compared to the actual situation where other structures like the capsular attachments may be injured especially if a fracture dislocation is encountered. Clinical trials are needed to confirm this finding.