Pia M Jungmann,Thomas Lange,Markus Wenning,Frédéric A Baumann,Fabian Bamberg,Matthias Jung
Ankle Sprains in Athletes: Current Epidemiological, Clinical and Imaging Trends Jungmann et al
ankle injuries,athletic injuries,computed tomography,joint instability,magnetic resonance imaging,sprains and strains
Purpose Ankle injuries are frequent sports injuries. Despite optimizing treatment strategies during recent years, the percentage of chronification following an ankle sprain remains high. The purpose of this review article is, to highlight current epidemiological, clinical and novel advanced cross-sectional imaging trends that may help to evaluate ankle sprain injuries. Methods Systematic PubMed literature research. Identification and review of studies (i) analyzing and describing ankle sprain and (ii) focusing on advanced cross-sectional imaging techniques at the ankle. Results The ankle is one of the most frequently injured body parts in sports. During the COVID-19 pandemic, there was a change in sporting behavior and sports injuries. Ankle sprains account for about 16–40% of the sports-related injuries. Novel cross-sectional imaging techniques, including Compressed Sensing MRI, 3D MRI, ankle MRI with traction or plantarflexion-supination, quantitative MRI, CT-like MRI, CT arthrography, weight-bearing cone beam CT, dual-energy CT, photon-counting CT, and projection-based metal artifact reduction CT may be introduced for detection and evaluation of specific pathologies after ankle injury. While simple ankle sprains are generally treated conservatively, unstable syndesmotic injuries may undergo stabilization using suture-button-fixation. Minced cartilage implantation is a novel cartilage repair technique for osteochondral defects at the ankle. Conclusion Applications and advantages of different cross-sectional imaging techniques at the ankle are highlighted. In a personalized approach, optimal imaging techniques may be chosen that best detect and delineate structural ankle injuries in athletes.
Ankle Sprains in Athletes: Current Epidemiological, Clinical and Imaging Trends Jungmann et al

Ankle injuries are frequent sports injuries. Despite optimizing treatment strategies during recent years, the percentage of chronification following an ankle sprain remains high. The purpose of this review article is, to highlight current epidemiological, clinical and novel advanced cross-sectional imaging trends that may help to evaluate ankle sprain injuries.

Systematic PubMed literature research. Identification and review of studies (i) analyzing and describing ankle sprain and (ii) focusing on advanced cross-sectional imaging techniques at the ankle.

The ankle is one of the most frequently injured body parts in sports. During the COVID-19 pandemic, there was a change in sporting behavior and sports injuries. Ankle sprains account for about 16–40% of the sports-related injuries. Novel cross-sectional imaging techniques, including Compressed Sensing MRI, 3D MRI, ankle MRI with traction or plantarflexion-supination, quantitative MRI, CT-like MRI, CT arthrography, weight-bearing cone beam CT, dual-energy CT, photon-counting CT, and projection-based metal artifact reduction CT may be introduced for detection and evaluation of specific pathologies after ankle injury. While simple ankle sprains are generally treated conservatively, unstable syndesmotic injuries may undergo stabilization using suture-button-fixation. Minced cartilage implantation is a novel cartilage repair technique for osteochondral defects at the ankle.

Applications and advantages of different cross-sectional imaging techniques at the ankle are highlighted. In a personalized approach, optimal imaging techniques may be chosen that best detect and delineate structural ankle injuries in athletes.

The ankle joint is one of the most commonly injured joints in athletes.1,2 Ankle sprains account for 40% of all sports injuries.3,4 Developing common and advanced cross-sectional imaging techniques aims to detect structural lesions at the ankle and to guide therapeutic strategies. This review primarily focuses on developments, changes and adaptations in injury patterns, imaging and treatment approaches that are a current focus of orthopedic surgeons in clinical practice. Besides lateral collateral ligament injury, other potentially associated injuries including syndesmotic injuries and osteochondral lesions are discussed. For review of tendon injuries around the ankle, we refer to other publications.5–10

For this review, an electronic search in PubMed (http://www.ncbi.nlm.nih.gov/pubmed) was performed to identify relevant studies that describe current trends in cross-sectional imaging after ankle sprain.

The lateral collateral ligament complex at the ankle consists of three ligaments. The most anterior anterior talofibular ligament (ATFL) runs from the anterior tip of the fibula horizontally to the talar neck. In most cases, it consists of two bands.11 The thin calcaneofibular ligament (CFL) runs from the lateral malleolar tip at the inferomedial border to the trochlear eminence of the calcaneus. The striated posterior talofibular ligament (PTFL) runs horizontally from the fibular malleolar fossa to the posterior talus, blending with the joint capsule. The deltoid ligament is the medial collateral ligament complex at the ankle. It consists of a deep and a superficial layer.12,13 The deep layer is composed of the anterior and posterior tibiotalar ligament. The superficial layer consists of the tibiocalcaneal, the tibiospring and the tibionavicular ligament and crosses two joints. The syndesmosis consists of the anterior and posterior syndesmosis and of the interosseous ligament. The anterior syndesmosis consists of the striated anteroinferior tibiofibular ligament (AITFL) and the frequent inferior accessory fascicle (Bassett’s ligament). It runs from the tibia in a slightly oblique course to the fibula.14–16 The posterior syndesmosis consists of the posteroinferior tibiofibular ligament (PITFL) and its inferior part, the transverse tibiofibular ligament.17 The interosseous ligament, a distal interosseous membrane expansion, runs from proximal tibial to distal fibular.18–20

Fifty-three percent of National Football League (NFL) Combine participants are reported to have a history of ankle injury.21,22 Acute ankle sprain is the most common lower limb injury in athletes, accounting for 16–40% of the injuries and 14% of the emergency visits.21,23–25 Ankle sprains have an incidence of 1 per 10,000 persons (8000 in Germany) per day.2,21,26 In professional team sports in Germany, the ankle is the most commonly injured body part in basketball (16.9%) and handball (14.7%). Also in the FIFA World Cup 1998–2012, the ankle was the most frequently injured body part (19%).27 In the 2014 Winter Olympics, the ankle was the second most commonly injured body region (12%).28 During the Summer Olympics, foot and ankle injury rates ranged from 0.09 to 0.42 injuries per athlete-years (Winter Olympics: 0.02 to 0.35).23 In the 2016 Summer Olympics, 8.8% of the athletes were referred for an ankle Magnetic Resonance Imaging (MRI), of which 99% had at least one abnormal finding (79% (sub)acute).29 The majority of sprains affect the lateral collateral ligament complex, which is injured in 85% of the ankle sprains.21 Total ligament ruptures occur in 10% of the cases, most frequently of the ATFL (65–85%) and CFL (75–85%).21,23,30 Additional injuries are osteochondral lesions, injury to the medial ligaments, the tibiofibular syndesmosis, the bifurcate ligament, the ligaments of the tarsal sinus, the peroneal tendons, and fractures.31,32 The medial collateral ligament complex is more resistant to trauma than the lateral. Therefore, medial collateral ligaments injuries are far less frequent than lateral collateral ligaments and occur in 5–15% of the ankle sprains, rarely in isolation. Usually, they occur in combination with lateral ligament tears, malleolar fractures, and syndesmotic tears. In more than 50% of the cases, the superficial and the deep medial collateral ligaments are affected. High ankle sprains include injury to the tibiofibular syndesmosis.33 Injuries to the syndesmosis occur in about 10% of the ankle sprains.34 Ice hockey is the most common sport to result in a high ankle sprain.35 High ankle sprain results in significantly higher time to return to play (average: 41–45 days) as compared with low ankle sprain (average: 1.4 days).35 Ankle instability has a high rate of chronification.36 Chronic ankle instability with persistent frequent residual symptoms, sprain recurrence and subjective ankle instability is observed in 10–40% of the cases.21,25,37,38 According to van Rijn et al, 5–33% of the patients still experienced pain 1 year after ankle sprain. After 3 years, one-third of the patients reported at least one re-sprain.36 Osteochondral lesions are found in about 6–7% of the ankles after sprain,39,40 in 40% of the patients with persistent ankle disability after sprain41 and in 42% of the ankle MRIs in asymptomatic soccer players.42 The ratio of prevalence at the talus versus tibia is about 20:1.43 Two-thirds of osteochondral defects at the talus are located medially and 1/3 laterally.40,44,45 The COVID-19 pandemic has influenced sporting activity and trauma visits.46 Social isolation, lack of access to facilities, spare time, home-schooling, and home-office resulted in training changes.46 The running-related injury rate increased 1.4-fold.46 However, only patients with severe injury showed up to the emergency room.47–49 Young athletes with minor sports injuries such as ankle sprains did not seek care.47,50 The percentage of patients undergoing surgery for ankle fractures remained stable.51

Sports injury is the cause of ankle sprain in 18% of the cases. In particular, basketball and soccer players are at risk. The injury mechanism implies plantarflexion, adduction, and inversion.15 The ATFL usually ruptures first, followed by the CFL. Due to the mechanism of the injury, PTFL ruptures as well as isolated ruptures of the CFL are extremely rare. PTFL ruptures usually only occur after ankle dislocation. Since the deltoid ligament is strong, medial malleolar fractures may occur instead of medial collateral ligament injuries. Injuries to the medial collateral ligaments usually occur in case of eversion and dorsiflexion trauma. They are usually combined with other injuries. The injury mechanism of syndesmotic injury may include external rotation of the foot, eversion of the talus and excessive dorsiflexion.33 Usually, the anterior syndesmosis ruptures first. The posterior syndesmosis may stay intact. Bony avulsion of the posterior syndesmosis at the tibia corresponds to the Volkmann fracture. Injuries of the medial collateral ligament and/or to the syndesmosis require examination of the proximal fibula to exclude Maisonneuve fractures and ruptures of the interosseous membrane of the shank. Although chronic ankle instability is considered a risk factor for osteoarthritis, overall only little posttraumatic osteoarthritis is observed.37 Three-dimensional (3D) stress MRI showed that the cartilage contact area in plantarflexion-supination compared to neutral-null position is reduced by about 1/3.52 In patients with chronic ankle instability, the cartilage contact area is even more severely reduced (by 41% horizontal tibiotalar and 56% tibiofibular, respectively; Figure 1a and b).52

The anamnesis should imply evaluation of the trauma mechanism (supination) and recurrence. The clinical examination should imply palpation (including the fifth metatarsal and the fibular head) and range of motion. Further, the squeeze test for assessment of the syndesmosis, and the talar drawer test should be included. Be aware, that injuries to the syndesmosis are frequently overlooked at initial presentation. The clinical examination is followed by conventional radiography if one of the Ottawa Ankle rule criteria applies. Excessive imaging has been described as a common mistake in the management of ankle sprains.21

Radiography helps to rule out fractures and to evaluate the congruency of the joint including the syndesmosis. According to the Ottawa ankle rules, conventional radiography in two planes including the Mortise-view (anterior-posterior with 10° to 20° internal rotation) and the lateral view is indicated when one criterion applies:25,30,53 Criteria include (i) pain at the posterior lateral malleolus (6cm), (ii) pain at the posterior medial malleolus (6cm), or (iii) impossibility of weight-bearing directly after trauma and during the examination; Criteria for conventional radiography of the foot in two planes are pain at palpation of (iv) the fifth metatarsal basis or (v) the navicular bone.30 Radiography is also indicated in osteoporotic patients or medial injury. Stress radiographs are obsolete in the acute setting and are controversially discussed in case of chronic instability.38

Computed Tomography (CT) imaging is indicated in case of suspicion for fracture but unremarkable radiography or for further evaluation of fracture lines. Performing cone-beam CT has the advantage of radiation dose reduction and evaluation under weight-bearing conditions (Figure 2a).54,55 Cone-beam CT under weight-bearing is most appropriate for the evaluation of the stability of the distal tibiofibular joint under compression. The syndesmotic distance is measured at the anterior and posterior tubercles of the tibia 10mm above the joint line (Figure 2b and c). A side-to-side-difference >2mm or posterior width >6mm is considered abnormal.56,57 Currently, there are no definite thresholds regarding tibiofibular displacement or malrotation.58 Congruency of the distal tibiofibular joint is assumed in case of (i) harmonious elliptical line, (ii) the fibula positioned in the tibial incisura, (iii) congruent positioning of the malleoli in relation to the talus, and (iv) equal clear space.59,60 Despite no definite cut-off value, malrotation can be assumed in the case of >15–20° external rotation of the fibula.61 Dual-energy and photon-counting CT may have several advantages as compared to conventional CT, including assessment of BME and metal artifact reduction.62–64 Dual-energy CT identifies BME around the ankle joint with a sensitivity of 88–92% and specificity of 82–93% (Figure 3a–c).65,66 Besides, new iterative projection-based MAR techniques show excellent metal artifact reduction not only for soft tissue reconstructions but also for reconstructions with bone Kernel (Figure 4a and b).

Routine MRI is not recommended for simple sprains.25 However, severe trauma, extreme clinical findings, suspicion of syndesmotic injury, persistent complaints, or uncertainty about the trauma mechanism may indicate cross-sectional imaging to help guide treatment.40,67 Despite its low sensitivity for chronic ankle instability, also for preoperative MRI is recommended.31,38,40,41 Standard high-resolution MRI protocols are suitable for patients after ankle sprain. The protocol usually includes coronal T1-weighted (T1w) TSE images, sagittal and coronal IMw fat-saturated (fs) TSE images, and transverse images either IMw fs or T2w (or both) TSE images, all with a slice thickness of ≤3mm. It is important to keep the echo time (TE) between 35 and 50ms for IMw sequences to mitigate “magic angle” artifacts.68 Acquiring images at two echo times may be useful in case of collateral ligament injuries. Fat suppression by the use of short-tau-inversion-recovery (STIR) sequences may be of advantage in cases with metal implants. Dixon sequences allow reconstruction of images with and without fat suppression.68 Since the tibiofibular syndesmosis has an oblique course, some radiologists recommend additional oblique transverse images, especially in cases with clinical suspicion of a syndesmotic injury.69 Alternatively, these oblique transverse images may be reconstructed from a 3D TSE sequence with no difference in accuracy (Figure 5).70–72 3D GRE sequences are inferior in depicting BME and therefore not suitable for the standard ankle protocol.73,74 Superiority of 3T and 7T over 1.5T MRI of the ankle with higher resolution was described.73 However, 7T only surpassed 1.5T ankle MRI for GRE sequences in runners. Tibiotalar bone edema-like lesions were barely visible at 7T.73 Using compressed sensing (CS) with slice-encoding for metal artifact correction (SEMAC) may result in excellent in-plane and through-plane artifact reduction,75–78 superior to high-bandwidth techniques for the evaluation of bone, BME, tendons, and the joint capsule in patients with total ankle arthroplasty or other large metallic implants (Figure 6a–d).76 In the case of small implants, standard TSE sequences or high bandwidth sequences should be used, since the image quality of CSSEMAC sequences is still inferior.78 At the ankle, the CS techniques may be combined with TSE, Dixon, and T2-mapping sequences without loss of image quality.79,80

Of the lateral collateral ligaments, the ATFL and the CFL have a hypointense signal on MR imaging and a linear shape.81 The strong PFTL has a striated, fan-like shape caused by fibrofatty components. Of the medial collateral ligaments, the thick, striated posterior tibiotalar ligament, the tibiocalcaneal ligament, the tibiospring ligament and the tibionavicular ligament can usually be identified on MRI. The anterior tibiotalar ligament cannot always be identified.12,13 Periligamentous edema and increased signal intensity, loss of striation as well as partial discontinuity indicate partial ruptures.12 Ligament discontinuity indicates complete ruptures. The overall accuracy of MRI for partial and complete tears of the ATFL is 74% and 79%, respectively (CFL: 66% and 88%, respectively).82 Tears usually occur in the middle third of the ligaments or at the talar or calcaneal insertion, respectively.81 After 3 months, evaluation on MRI is difficult with a decreasing accuracy due to scarring. For chronic ankle instability, increased ATFL length and width, as well as large angles between ATFL and PTFL, have been described.83,84 Still, the sensitivity for the detection of collateral ligament lesions is low in chronic cases (28–38%).31 Higher SNR of injured ATFL compared to controls and correlations of higher SNR with remnant condition, reparability, and outcomes are reported.83,85,86 However, using SNR for quantitative measurements remains questionable. For more sophisticated quantitative measurements of ligament signal intensity at the ankle, UTE-based T2* values are being used.87

The anterior and posterior syndesmosis usually have a fascicular appearance on MRI. Thickening, increased signal, loss of fascicular appearance, and soft tissue swelling indicate partial rupture of the syndesmosis. Discontinuity, retraction, or curved appearance indicate complete rupture of the syndesmosis. In the acute setting, tibiotalar joint effusion indicates syndesmotic injury.88 Differentiating between disruption and syndesmotic instability is challenging.58 Bone contusions are seen in >2/3 of syndesmotic injuries.34 Posterior malleolus BME (in 60%) and posterior malleolus fracture (in 16%) indicate posterior syndesmosis rupture and consecutive instability.72 The sensitivity of MRI decreases from 94% for <6 weeks to 54% for >12 weeks after injury.72

Generally, posteromedial osteochondral lesions are associated with chronic instability, while lateral lesions are more likely to be the result from acute trauma. Medial defects are usually located posteromedially with a deep osseous involvement based on osteochondral compression.44,68 Lateral talar defects are usually located anterolaterally or midlaterally with superficial cartilage delamination or flake fracture based on shearing injury.44 At the tibia, there is no preferred location.89 Regularly at the anteromedial tibial plafond, an osteochondral concavity can be observed (Notch of Harty; Figure 7a).90 Biochemical quantitative MR techniques may help to detect cartilage degeneration and cartilage defects (Figure 7a and b). Higher relaxation times indicate more severe cartilage matrix degeneration (see below). The sensitivity for the detection of cartilage lesions at the talus is about 50–75% for conventional MRI,74 75–87% for MR arthrography (MRA)91 and 89–92% for CT arthrography (CTA; Figure 7c and d).74,91 If lesions are detected on MRI, defect size is overestimated (52%) or underestimated (24%) in many cases.92 A non-invasive method for optimized cartilage evaluation is MRI under axial traction (Figure 7e and f). The radiographic Berndt and Harty classification for osteochondral lesions was transferred to MRI by Nelson and Dipaola (Figure 8).93–95 The grades are associated with pain intensity.96 It is clinically important to differentiate between stable grade II (demarcation of the fragment/partial loosening) and unstable grade III (total loosening, surgical treatment indicated).97 Indirect signs for osteochondral involvement at the talus include joint effusion,88 cartilage signal changes, and subchondral BME. Frequently, subchondral BME is the only indicator of talar cartilage defect on MRI.74,98

As a common finding after an ankle injury, BME helps determine the trauma mechanism.98 Following inversion injury, BME involves the lateral malleolus, the medial talus, and the medial tibia.98 After ankle sprain, BME and osteophytes were associated with swelling, reduced plantarflexion, and pain.99 BME of the medioplantar talar head is associated with severe ligamentous injury in ankle sprain, in particular to the medial and lateral collateral ligament complex.100 Avulsion injuries are difficult to detect on MRI since they are not always accompanied by a BME.

Interestingly, MR imaging findings do not correlate with return to play following an ankle sprain.35 Imaging findings in patients with persistent ankle instability are mainly ATFL injuries (54%) and osteochondral changes (40%) including cartilage lesions, osteophytes, and BME.41,99 To assess osteoarthritis on MRI, semi-quantitative scoring methods have been developed for the knee (WORMS),101 the shoulder (SOAS),102 the hip (SHOMRI),103 and also for the ankle (Ankle Osteoarthritis Scoring System, AOSS).104

Imaging, including MRI of the ankle, plays an increasing role in pre-signing medical examination.105 Working closely with the clinicians and being aware of the high prevalence of findings and ethical and medicolegal issues is required.105 In professional soccer players, a high prevalence of asymptomatic osteochondral lesions in at least one of the joints of the foot and ankle was described (Figure 9a and b). Seventeen percent of all players showed cartilage lesions with >50% lesion depth. Subchondral bone marrow edema was present in all of these cases.42 Eighty-seven percent of players showed degenerative joint disease (Mostly Kellgren–Lawrence grade 1) and 64% synovitis. Tibiotalar cartilage T2* values are increased in football players.106 Half of the NFL Combine participants were shown to have signs of osteoarthritis around the ankle joint.21,22

Quantitative MRI techniques were applied for cartilage imaging at the ankle to assess cartilage matrix quality, cartilage stress, and early degeneration. Running, lateral ankle instability, and osteochondral lesions result in increased tibiotalar or subtalar cartilage T2, T2* or T1rho relaxation times.107–113 Combined ATFL and CFL rupture resulted in higher T2 values with worse clinical scores than isolated injury.108,111 Early cartilage matrix degeneration was not halted by ATFL repair or reconstruction.114

Several new MR imaging techniques with CT-like image impression have been published, such as zero echo time (ZTE), ultra-short echo time (UTE), or 3D T1w spoiled gradient-echo MRI (T1GRE) sequences, which may all be applied at the ankle (Figure 10a–c).115–118 However, all techniques currently still have their limitations. Inverted T1GRE sequences are easiest to acquire and have the highest spatial resolution and image contrast.116,119 As a disadvantage, not only bone is depicted bright on inverted images but also fluid, ligaments, and tendons. Therefore, detection of tendon calcifications or avulsion fractures is still challenging on T1GRE sequences. BME cannot be differentiated from sclerosis.119 On UTE images, tendons may be differentiated from bone, sclerosis, and calcification, but ligaments and fluid still appear bright.116,118–121 Disadvantages are motion artifacts, blurring, signal inhomogeneity, low SNR, lower diagnostic image quality, and long acquisition times.119,122 ZTE is most promising for bone imaging on MRI since only calcified structures are shown bright.123–125 BME, ligaments, and tendons can be differentiated from bone, sclerosis, and calcifications. It also has reduced acoustic noise levels. Still, ZTE images have severe chemical shift artifacts, low SNR, and image quality, although cortical delineation, cortical thickness, and pathology visualization were reported similar to CT126 with good performance for the shoulder,124,127 and hip.123 For the ankle joint, 3D intermediate-weighted (IMw) turbo spin-echo (TSE) sequences and T1GRE sequences were applied so far.57,117

In doubt of syndesmotic injury, complementary stress ultrasonography is recommended.128 After acute ankle sprain, ultrasonography may be used for evaluation of superficial tendons, ligaments and muscles, while it is inadequate for the evaluation of deeper structures,129 for evaluation of the lateral collateral ligaments and the anterior syndesmosis standardized ultrasound may replace MRI.130 A high correlation of ligament injuries detected was reported for the two modalities. However, ultrasonography is investigator dependent and should be performed by an experienced sonographer.

In recent decades, the most common therapy of ankle sprains shifted from surgical to conservative treatment including early functional training, with bracing and physiotherapy.21,25,30 After initial treatment according to the “RICE” regime with rest, ice, compression and elevation, the treatment strategy depends on the severity of the injury. Grade I is defined by sprain and partial rupture of the lateral collateral ligaments and is functionally treated with tape for 4 to 6 weeks with weight bearing as tolerated. Grade II is defined by total rupture of the LFTA and LFC and is treated with orthesis for 6 weeks and weight bearing as tolerated. Grade III is defined by rupture of the collateral ligaments plus additional medial collateral ligament injury or/and additional other concomitant injuries. In case of grade III injuries, immobilization for a maximum of 10 days may be of advantage, followed by functional treatment in an orthesis until 6 weeks after injury.30 Despite the high rate of chronification, the majority of cases remain on conservative therapy after 6 months.21,25,37,38 External stabilization of the ankle during sports is recommended for at least 1 year following an index sprain, and even longer in chronic instability if functional training and compensation for mechanical deficits is insufficient (so-called Non-Copers).131 Physiotherapy is helpful in case of recurrence and persistent instability including strengthening and proprioception training. A recent review and meta-analysis evaluated the effects of Kinesio Taping on sports performances and ankle functions in athletes with chronic ankle instability.132 The authors report a stabilizing effect of ankles with significant improvement in gait functions, reduction in inversion and eversion range of motion, decrease in the muscle activation of the long peroneus and decrease in the postural sway in movement in the mid-lateral direction.132

Isolated total ruptures of lateral collateral ligaments may only be treated surgically in high-level athletes with severe instability.38 Nowadays, also isolated ruptures of the anterior syndesmosis are treated conservatively if the distal tibiofibular congruency (eg, on weight-bearing cone-beam CT) is maintained. Additional ruptures of the interosseous membrane or the posterior syndesmosis with consecutive instability and/or chronic pain may require surgery.57,133 Other indications for surgery include interposition of lateral collateral ligaments, (osteo)chondral lesions, impingement, and obviously dislocated fractures.38 When surgery is indicated, lateral collateral ligament repair is the treatment of choice.38 In chronic cases, surgical reconstruction may be considered (modified Brostrom procedure).25,134–136 It implies refixation of the scar tissue to the lateral malleolus with or without up to three intraosseous suture anchors.137,138 In case of treatment failure, generalized laxity, or poor ligament quality, lateral ligament reconstruction (using gracilis autograft or allograft) of both the ATFL and CFL should be considered.38,134 Reconstruction has the risk of overconstrainment which may produce a feeling of tightness of the ankle, which is not observed after repair, and may result in early osteoarthritis.139 Alternative or additional therapeutic approaches include platelet-rich plasma (PRP) injections, which can stimulate tissue healing.37 For surgical treatment of syndesmotic injury, advantages of suture-button fixation systems over screw fixation are (i) no screw removal, (ii) early functional rehabilitation with immediate full weight bearing, and (iii) better outcomes with earlier return-to-sport.67 Despite the decreased incidence of malreduction, elongation of the tight rope can occur. Therefore, initial overcorrection is required. Intermittent trends towards double-suture-button fixation were abandoned due to insufficient superiority. Although nonoperative treatment can be considered a good option for patients with OCL at the talus.140 OCL lesion size at the talus increased by 11% within 3 to 10 years.140 In symptomatic patients, cartilage repair surgery is considered treatment of choice.45,141–143 None of the surgical strategies is superior.141,144–148 “Magnetic Resonance Observation of Cartilage Repair Tissue” (MOCART) scores vary around 60 with frequent BME, cysts, underfilling, and tissue irregularities.147,149–157 BME may have an impact on clinical outcomes.155,156 Although after matrix-associated chondrocyte implantation (MACI) better filling has been reported,157 need for early return-to-sports leads to extensive use of microfracturing or Autologous Matrix-Induced Chondrogenesis (AMIC; microfracturing plus collagen I/III matrix). Autologous osteochondral transplantation (OCT) is a good option for large defects.149,158 The newest technique is minced cartilage implantation.146 Briefly, intact native hyaline cartilage is minced into small pieces with a specific device or knife, mixed with PRP, filled as a paste-like mixture into the defect, and covered with thrombinator/fibrin glue (Figure 11a–d).146

There is a high prevalence of ankle injuries during the Olympic Games and other big tournaments. Ankle sprain is the most common injury. After clinical examination, conventional radiography should be performed according to the Ottawa ankle rules. A summary of new technical developments of cross-sectional imaging that may help in the context of imaging after ankle sprain is provided in Table 1. Cone-beam CT is the imaging method of choice to evaluate the congruency and instability of the distal tibiofibular joint under weight-bearing conditions. BME may be detected by the use of dual-energy or photon-counting CT. In case of severe injury, early MRI is recommended since the sensitivity for the detection of structural defects decreases over time. Advanced MR techniques using native and stress 3D IMw TSE sequences of the ankle may help in the evaluation of chronic ankle instability. While CTA is currently the method of choice for the evaluation of osteochondral lesions at the ankle, MRI with axial traction may represent a good non-invasive alternative. Early cartilage matrix degeneration in patients with chronic ankle instability and osteochondral lesions may be detected via quantitative MR imaging techniques. More advanced degenerative changes may be assessed using the AOSS. Complementing MRI with CT-like images may help detect osseous abnormalities. Stress ultrasonography helps in doubt of syndesmotic injury. Ultrasonography may detect injuries to the lateral collateral ligaments and the syndesmosis reliably when performed by experienced investigators. In case of ankle sprain in athletes, besides looking for ruptures of the lateral collateral ligaments, it is most important to pay attention to additional injuries of the bone, the syndesmosis, the medial collateral ligaments, osteochondral injuries, and tendons to guide clinical treatment decisions. There was a paradigm shift towards conservative treatment for ankle sprain and syndesmotic injuries with an emphasis on secondary prevention. The current surgical treatment of unstable syndesmoses is single suture-button fixation. Besides microfracturing and AMIC, minced cartilage implantation represents a new cartilage repair technique.

Advanced cross-sectional imaging techniques at the ankle that best detect and delineate structural and ultrastructural abnormalities may be applied in a dedicated, personalized approach after ankle injury in athletes.