Snowboarder's Ankle

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Introduction[edit | edit source]

Snowboarding

In recent times snowboarding has increased in popularity dramatically, with this increase in popularity comes an increase in a distinct ankle injury which has been aptly termed ‘snowboarder’s ankle’. Snowboarding is a popular winter sport that includes riding a single board down a ski slope or on a half-pipe snow ramp. Snowboarder's Ankle is the common term for a fracture of the lateral process of the Talus (LPTF), often overlooked initially and misdiagnosed as a severe ankle sprain.[1] The term snowboarder’s ankle comes from this fracture being 15x more likely amongst snowboarding associated ankle injuries than any other ankle injuries. Ankles are involved in 12-17% of snowboarding-related injuries.[2] A fracture to the lateral process of the talus in snowboarders can account for one-third of ankle fractures in this population. Various types of snowboard equipment, rider stance, and snowboarding activity tend to result in several types of injury. Soft boots give the snowboarder nearly twice the risk of ankle injury compared with hard boots.[3] Sideways motion, soft (non-hard shell) boots, and being strapped to the board are all factors that influence the higher rate.[4]

Anatomy[edit | edit source]

Talus bone (lateral view)

The talus is one of seven articulating foot bones that are situated between the tibia and fibula of the lower leg and the metatarsal bones of the midfoot. The talus constitutes the lower part of the ankle joint and articulates with the medial malleolus of the tibia and the lateral malleolus of the fibula. The ankle joint permits dorsiflexion and plantarflexion of the foot. The underneath aspect of the talus articulates with the calcaneus forming a subtalar joint.[5] This joint enables inversion and eversion of the foot. The talus also articulates navicular bone allowing for subtle movements of the midfoot that play a vital role when walking on uneven ground. The lateral process of the talus is a wedge-shaped projection of the talar body. The top of the lateral process articulates with the fibula and makes a part of the lateral gutter of the ankle joint. The bottom of the lateral process forms the anterior part of the posterior subtalar joint. As the lateral process is involved in both the ankle and subtalar joints, it is significant in almost all foot movements.[6]

Mechanism of Injury[edit | edit source]

The mechanism of injury is likely that the injured ankle was the leading foot at the time of the fall. Recent research indicates that forced ankle joint dorsiflexion, eversion, and external rotation of the tibia causes the lateral process of talus (LPT) to shear away as it compresses against the calcaneus.[7] Dorsiflexion causes the Talus to become locked in place by the surrounding bones, the ankle roll outwards then causes that specific small area (LPT) to be compressed in between the calcaneus and the lateral malleolus of the fibula with sufficient force applied, the Talus will fracture, causing snowboarder’s ankle.  It can occur during a landing from an aerial maneuver or a jump, especially when the landing has been over-rotated.[8][4]

Causes[edit | edit source]

The cause of the prevalence of the fracture of the Talus bone in snowboarders continues to be debated. In all likelihood, the probable cause is the convergence of both the biomechanics and equipment required for the sport. There is the unnatural sideways biomechanical motion of snowboarding. This is coupled with boots that are strapped to the board, which offer no prompt release upon falling. And then there are the boots which are different from the rigid boots worn in downhill skiing. Snowboarders’ boots are softer and suppler, providing for those thrilling jumps and amazing acrobatics. The more flexible construction of snowboarding boots also indicates that they are less protective on those hard landings from high up causing higher rates of foot and ankle injuries, including snowboarder’s ankle. Whenever there is sufficient force to break a bone, there is possible damage to ligaments and tendons as well.[9]

Classification[edit | edit source]

According to Hawkins classification,

  • Simple fractures (Type I): extending from the talofibular articular surface to the posterior talocalcaneal articular surface of the subtalar joint.
  • Comminuted fractures (Type II): involving both the articular surfaces and the entire lateral process.
  • Chip fractures (Type III): arising from the anterior and inferior portion of the posterior articular process involving only the subtalar joint and not extending into the talofibular articulation.[10]

Boack described a modified classification system that can be used to diagnose a fracture of the lateral process of the tibia. This classification covers four types of fracture, each type subdivided depending on the severity of the bony injury, degree of the Chondral lesion, and ligamentous stability. Based on their description, lateral process fractures are divided into four types.

LPT Fracture

Type 1: A small chip or avulsion fracture (< 0.5 cm):

  • 1a - Small (extra-articular) fragment of the lateral process of the talus;
  • 1b - Small fragment of the isolated medial tubercle of the posterior process of talus;
  • 1c - Small (intra-articular) fragment of the lateral process of the talus.

Type 2: An intermediate fragment (0.5-1.0 cm) with some form of displacement:

  • 2a - Extends into the subtalar joint without the involvement of the talofibular joint;
  • 2b - Isolated fracture of the complete lateral tubercle of posterior process.

Type 3: A large fracture fragment (> 1 cm) with associated damage to  the ankle as well as the subtalar joints:

  • 3a - Single large fragment of the lateral process extending from the talofibular articular surface to the posterior facet of the subtalar joint;
  • 3b - Comminuted fracture of the complete lateral process;
  • 3c - Fracture of the whole posterior process of the talus.

Type 4: A severe form of fracture of either of the processes along with associated instability or dislocation of the subtalar joint.[11]

[12]

Clinical Features[edit | edit source]

A snowboarder’s ankle has a similar presentation to that of a badly sprained ankle which is why it is important to monitor symptoms if an ankle injury occurs on the slopes. A history of an ankle sprain while snowboarding when the foot and ankle are fixed in stiff boots and strapped to the board whilst twisting the ankles to change direction should certainly arouse suspicion. A huge 33-41% of these injuries are reported to be missed on initial inspection and just diagnosed as a bad sprain as X-rays in this area are often hard to distinguish. [13]

Symptoms of this injury may include:

  • Extreme tenderness and sensitivity to pressure around the back of the ankle. Tenderness is localized to a region about 1cm inferior to the tip of the lateral malleolus. Although often mimicking a lateral ankle sprain it may be difficult to specifically elicit this site.
  • Swelling to the area.
  • Ecchymosis or a degree of bruising
  • There is normally difficulty in walking and an inability to bear weight.

The warning signs for a snowboarder's ankle injury involves inflammation and chronic pain. Those who sprained their ankles many times before and complain about persistent pain and swelling are also possible candidates for this specific type of ankle injury.[13]

Investigations[edit | edit source]

A plain radiograph and CT images showing LPTF

It may be possible to identify the fracture on plain X-rays, but the fracture line is often quite subtle and difficult to see due to overlapping bony structures.[14] Both lateral (ankle at 90°) and ankle mortice views are recommended for a routine investigation. Ultrasound can be useful for the detection of cortical disruption and ankle joint space effusion; However, follow-up CT or MRI is often used to visualize the fracture line more clearly and provide information to thoroughly understand the extent of the injury. A CT scan should be considered when these symptoms occur for a long period of time because the scan will provide accurate detail if there is a suspected fracture.[15] The sequelae of missed fractures result in malunion, nonunion, long-term disability, and degenerative arthritis of the subtalar joint.[15][10]

Medical Management[edit | edit source]

Recognizing this injury as early as possible can help reduce the likelihood of subsequent ankle joint degeneration and resulting functional disability. Appropriate intervention depends on the size, location, and displacement of the fragment, the degree of articular cartilage damage, and instability of the subtalar joint. [16]

  • Non-operative management

If the fracture is non-displaced (< 2 mm)  then 6 weeks of non-weight bearing on crutches and a Removable plastic cast or boot is the usual treatment. In the early stages of treatment, ice packs and pain-relieving medications can be helpful in controlling pain and reducing swelling.[11]

  • Operative management
Fixation of the lateral process fracture

However, If the displacement is > 2mm, an open reduction and internal fixation (ORIF) may be performed. This involves an incision on the lateral aspect of the ankle, through which lag screws or wires are used to stabilize the bone fragment to the talus body. If there are any loose bodies found during the surgery, these are also removed. In instances of an associated subtalar dislocation, up to 50% of athletes can have an additional osteochondral injury. In these cases, emergency administration is recommended to relocate the subtalar joint, and arthroscopic assessment should be used to visualize the articular surface and to excise any loose fragments, preventing subsequent problems. The treatment strategy based on Boack’s classification is compiled in Table 1.

Classification Fracture Characteristics Management
Type 1a, 1b < 0.5 cm, extra-articular Conservative
Type 1c < 0.5 cm, displaced, intra-articular Arthroscopic excision
Type 2a, 2b 0.5-1 cm, displaced Arthroscopic assessment of chondral lesion
Type 3a > 1 cm single fragment Arthroscopic assisted screw fixation
Type 3b > 1 cm or multi-fragmentary Open reduction and internal fixation (ORIF)
Type 3c Entire process fracture Open reduction and internal fixation (ORIF)
Type 4 Fracture associated with a subtalar dislocation Emergency reduction, subsequent arthroscopic assessment of chondral lesion

Table 1: The Management strategy for the Fracture of the lateral process of the talus.[17]

Physiotherapy Treatment[edit | edit source]

Initial treatment for snowboarder’s ankle includes:

  • Rest, Ice, Compression, and Elevation
  • Initial immobilization for a minimum of 6 weeks (CAM walker or plaster cast)
  • Surgery when there is a severe displacement of the fracture

The aim of treatment in these cases is to minimize swelling, inflammation, and pain, and to provide the best conditions for healing to take place. Once the bones are healed, exercise and physiotherapy can be started to aid in the gradual restoration of motion, strength, and function of the ankle joint. Hydrotherapy exercises are very helpful in regaining the ankle range of movement. Manual therapy is important and can help to restore normal ankle movement. Non-weight bearing exercises, pool running using a Buoyancy Belt, also allow the patient to regain fitness.[18] It is also important to introduce a balance and strength program for the lower limb. Intensive rehabilitation reduces the recurrence of future injury. The final stage is getting fitness back and protecting from further injury.  This can be done by using an ankle brace during the sport. There is also some evidence to suggest that hybrid or mid-stiffness boots are the safest forms of boots for protecting the ankles.[19]

[20]

Complications[edit | edit source]

Potential complications of surgery include general complications like:

Complications that are particular to surgery for a lateral talus process comprise:

  • Painful implants: Occasionally, hardware like screws that were used to stabilize the fracture will require removal at a later stage.
  • Nonunion: Sometimes the fracture fragments will fail to heal and may need to be removed.
  • Arthritis of the Ankle or Subtalar joint: These joints are affected by this injury and can develop arthritis secondary to injury later on. It should be noted that with non-operative treatment, there is also the potential that arthritis involving the outside of the ankle joint or the subtalar joint can develop.[22]

Recovery[edit | edit source]

Typically, recovery time from surgery needs six to eight weeks of relative immobilization and non-weight bearing, if the fracture has been stabilized (fixed with screws). If the fracture fragments were just cleaned out (debridement), then weight bearing can be started once the patient feels comfortable. Most athletes are able to go back to normal physical activity within 4 to 6 months. However, if missed or improperly treated the outcome is poor, with complications including chronic pain, joint instability, arthritis, or loss of mobility. In general, 80% of people with this fracture make a return to pre-injury levels in their sport. [9]

Prevention[edit | edit source]

  • There is no definite route to avoid the injury while snowboarding, but wearing well-built snowboarding boots that provide flexibility while maintaining stability can be beneficial. Being properly trained in snowboarding techniques can also help to avoid the bad landings that often cause snowboarder’s ankle.
  • The use of a Wobble Board to improve balance and proprioception can aid to prevent ankle injuries by improving proprioception and ankle stability. The wobble board, together with ankle braces, is commonly used in the rehabilitation of ankle instability. Wobble boards are designed to help the re-education of the proprioceptive system by improving sensory receptor function, required for snow-based activities.
  • Strengthening exercises with resistance bands can also help improve proprioception as well as improve multi-planar movements that are needed to snowboard.
  • Wearing a sports ankle brace and high cut shoes can also provide added support to the ankle. This acts as physical restraint and helps to prevent going over on the ankle.
  • Taping & Strapping.[23]

References[edit | edit source]

  1. Noble J, Royle SG. Fracture of the lateral process of the talus: computed tomographic scan diagnosis. British journal of sports medicine. 1992 Dec 1;26(4):245-6.
  2. Kirkpatrick DP et al. The snowboarder's foot and ankle. Am J Sports Med 1998; 26:271-7
  3. Mahmood B, Duggal N. Lower extremity injuries in snowboarders. Am J Orthop. 2014 Nov;43:502-5.
  4. 4.0 4.1 Wijdicks CA, Rosenbach BS, Flanagan TR, Bower GE, Newman KE, Clanton TO, Engebretsen L, LaPrade RF, Hackett TR. Injuries in elite and recreational snowboarders. British journal of sports medicine. 2014 Jan 1;48(1):11-7.
  5. Lee C, Brodke D, Perdue Jr PW, Patel T. Talus Fractures: Evaluation and Treatment. JAAOS-Journal of the American Academy of Orthopaedic Surgeons. 2020 Oct 15;28(20):e878-87.
  6. Sullivan MP, Firoozabadi R. Fractures of the Lateral Process of the Talus. Fractures and Dislocations of the Talus and Calcaneus. 2020:97-106.
  7. Funk JR, Srinivasan SC, Crandall JR. Snowboarder's talus fractures experimentally produced by eversion and dorsiflexion. The American journal of sports medicine. 2003 Nov;31(6):921-8.
  8. Boon AJ, Smith J, Zobitz ME, Amrami KM. Snowboarder's talus fracture: Mechanism of injury. The American journal of sports medicine. 2001 May;29(3):333-8.
  9. 9.0 9.1 Mahmood B, Duggal N. Lower extremity injuries in snowboarders. Am J Orthop. 2014 Nov;43:502-5.
  10. 10.0 10.1 Majeed H, McBride DJ. Talar process fractures: an overview and update of the literature. EFORT open reviews. 2018 Mar;3(3):85-92.
  11. 11.0 11.1 Boack DH, Manegold S. Peripheral talar fractures. Injury. 2004 Sep 1;35:SB23-35.
  12. Talus fracture, snowboarder's ankle. Available from: https://www.youtube.com/watch?v=jY76m6wIlDg
  13. 13.0 13.1 Kramer IF, Brouwers L, Brink PR, Poeze M. Snowboarders’ ankle. Case Reports. 2014 Oct 29;2014:bcr2014204220.
  14. Paul CC, Janes PC. The snowboarder's talus fracture. InSkiing Trauma and Safety: Tenth Volume 1996 Jan. ASTM International.
  15. 15.0 15.1 Von Knoch F, Reckord U, Von Knoch M, Sommer C. Fracture of the lateral process of the talus in snowboarders. The Journal of bone and joint surgery. British volume. 2007 Jun;89(6):772-7.
  16. Tucker DJ, Feder JM, Boylan JP. Fractures of the lateral process of the talus: two case reports and a comprehensive literature review. Foot & ankle international. 1998 Sep;19(9):641-6.
  17. Hörterer H, Baumbach SF, Mehlhorn AT, Altenberger S, Röser A, Polzer H, Walther M. Fractures of the lateral process of the talus-snowboarder's ankle. Der Unfallchirurg. 2018 Sep 1;121(9):715-22.
  18. Dann K. Snowboarding. InFoot and Ankle Sports Orthopaedics 2016 (pp. 541-547). Springer, Cham.
  19. McDonah MR. Trauma risks and prevention strategies for snowboarders. Journal of the American academy of nurse practitioners. 2000 Dec;12(12):517-21.
  20. Ankle Strengthening Exercises for Snowboarders. Available from: https://www.youtube.com/watch?v=CVE7PVGUgr8&feature=youtu.be
  21. Chan GM, Yoshida D. Fracture of the lateral process of the talus associated with snowboarding. Annals of emergency medicine. 2003 Jun 1;41(6):854-8.
  22. da Fonseca LF, Pontin PA, Magliocca GD, Arliani GG, Roney A, de Cesar Netto C, Bastías GF, Chaparro F, Zhu Y, Xu X, Ramirez C. An International Perspective on the Foot and Ankle in Sports. Baxter's The Foot and Ankle in Sport. 2020 Jan 25:454.
  23. Bladin C, McCrory P, Pogorzelski A. Snowboarding injuries. Sports medicine. 2004 Feb;34(2):133-8.