Technique manages ankle trauma in athletes, restores 360° ring of stability
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Historically, management of ankle fracture pathology has focused primarily on obtaining congruity of the ankle mortise with focused surgical restoration of anatomic osseous alignment.
Unfortunately, underappreciated disruption of the syndesmosis and deltoid complex has led to suboptimal clinical results, particularly in the high-level athlete. Furthermore, technical considerations relating to syndesmotic fixation methods and historical teaching dictating that restored osseous mortise alignment would secondarily allow for deltoid complex healing have further complicated optimal management and outcomes of these injuries.
Since the advent of suspensory fixation devices for stabilization of syndesmotic disruption, significant improvements, not only with improved anatomic reduction but also with more efficient progressive return to function avoiding the need for secondary surgeries, have been noted, as well. Additionally, considerable work, including studies by Beat Hintermann, MD, and James A. Nunley II, MD, focused on the effect of the deltoid ligament complex particularly as it relates to trauma, has elucidated important concerns regarding anatomic restoration of physiologic function of this ligament complex in maintaining talar congruity within the weight-bearing ankle mortise. Building on these principles, application and clinical efficacy of this medial-sided restoration in the elite-level athlete has been further demonstrated and validated by Robert B. Anderson, MD.
Source: Kirk A. McCullough, MD
In this light, consideration of the functional 360° ring of stability of the ankle mortise is critical, particularly in consideration of aggressive return to functional rehabilitation timelines. This concept importantly considers not only effective techniques of surgical stabilization, but equally, if not more importantly, the accurate identification of subtle instability patterns that are frequently underappreciated with historical means of diagnosis. An improved understanding of this concept will help progress treatment outcomes to focus on return to preinjury performance, not just simple return to activity.
Preoperative considerations
Without question, certain fracture patterns require increased clinical suspicion of deltoid and syndesmotic complex injury. Classically understood external rotation mechanisms where the foot exerts an external rotation and abduction force on the mortise lead to a spectrum of syndesmotic and medial-sided (eg, deltoid ligament and/or medial malleolar) disruption. Unfortunately, observed clinical anatomic disruptions do not always fit historical-based classification schema and, as such, arguably mandate more effective identification of these disruptions to treat the presenting injury pathology rather than simply relying upon the observed radiographic nature of osseous disruption. While classically this has included use of stress radiographs, technical concerns with ease of reliable reproducibility among clinicians have been raised, as well as frequent issue with patient tolerance of these maneuvers when performed in the clinic. Therefore, the clinician’s index of suspicion needs to remain high and, as with many other conditions, ultimately is a multifaceted assessment, including reported/observed injury mechanism, plain film radiography and clinical examination to ultimately determine the need for further imaging modalities and potential surgical intervention. This is particularly pertinent in the cleated athlete where rotational injury mechanisms with a planted foot are likely to occur. In the setting of recognized posterior malleolar pathology, CT scan imaging has become a modality of choice for preoperative planning as it not only more accurately characterizes the size and extent of posterior tibial fracture, but also identifies issues such as fracture comminution or intercalary fragment interposition that can assist in intraoperative fracture management considerations. Weight-bearing CT has become increasingly effective (particularly in the delayed presentation setting) to provide comparison “stress” views of the ankle mortise to understand subtle diastasis of the syndesmosis and the medial clear space otherwise frequently missed on standard radiographs.
Intraoperative considerations
Diagnostic considerations
Stress fluoroscopy is frequently cited as the primary means by which ligamentous laxity and the extent of soft tissue injury in ankle trauma is identified. Although certainly improved in efficacy when performed in an intraoperative setting as compared to its limitations on an awake patient, the lack of sensitivity to subtle pathology and inconsistent reproducibility among clinicians of varying degrees of experience make it suboptimal as a definitive means of injury identification.
As such, liberal use of intraoperative arthroscopy to identify more subtle pathology is warranted (Figures 1 and 2). Although this does add a degree of complexity in the initial set-up of a case, once performed with some consistency, any initial perceived “inconvenience” is quickly adopted by the operative staff and the value is recognized by the treating surgeon. Furthermore, the advent of needle-based arthroscopy facilitates the ability to do this less invasively and further decrease any potential concern for fluid extravasation with larger bore cannula arthroscopy. This value includes not only the ability to identify soft tissue injury, such as syndesmotic and/or deltoid disruption, but also cartilage trauma that certainly could portend a worse prognosis not otherwise realized unless an MRI had been obtained preoperatively.
Means of stabilization
Posterior malleolus
Necessity and means of fixation of posterior malleolar fractures largely depend upon the extent of injury. Given the large proportion the posterior complex provides to overall distal syndesmotic complex stability, recognition of the injury remains of utmost importance. With small avulsions that involve a minimal amount of articular surface, syndesmotic stabilization alone can suffice. With displaced fragments involving a larger portion of the joint surface or when comminution/intercalary fragments are present that prevent anatomic reduction, the need for open reduction exists as this provides stability not only to the joint surface, but to the posterior syndesmotic soft tissues, as well. Fixation in these cases largely depends on positioning and exposure and can vary from cannulated, partially threaded screws to posterior plating. Following stabilization of the posterior malleolus, fixation of the anterior syndesmosis can include either single suspensory fixation or direct repair of the anterior inferior tibiofibular ligament with suture tape anchor-based repair, such as the InternalBrace system (Arthrex).
Syndesmosis stabilization
Although static stabilization with screws was historically used with frequency, concerns regarding appropriate screw diameter, necessary length and associated cortical capture, anatomic malreduction, and when and if screw removal was necessary has complicated their use. Modern day stabilization has instead focused on means of dynamic stabilization of the syndesmosis with suture button suspensory fixation constructs like the TightRope (Arthrex). Numerous studies have demonstrated not only the ability of these devices to withstand the stress of early weight-bearing, but have also demonstrated improved technical aspects of syndesmotic stabilization, including decreased risk of malreduction, and have essentially eliminated the need for routine hardware removal considerations.
When performed without the need for posterior malleolar fracture fixation, the most common construct utilized is one that incorporates two separate syndesmosis implant systems placed parallel to the tibiotalar articulation and equidistant respectively from the radiographic center of syndesmotic articulation seen on a lateral X-ray view (Figures 3, 4 and 5). This is routinely executed utilizing a low profile one-third tubular plate construct for two reasons: 1) fixation above and below the suspensory fixation constructs limits the risk of stress riser fracture propagation, particularly for a contact athlete; and 2) centers the fixation constructs within the plate and fibula, avoiding asymmetric edge loading of the button/fibular cortex and shares the load/stress over a larger surface area (Figure 6). These constructs are tensioned with the ankle in neutral to slight dorsiflexion to avoid over-tensioning/constraining the joint and with a bump under the Achilles leaving the heel free to avoid excess anterior translation of the talus in the mortise. In the presence of anterior-based avulsion of the syndesmosis complex from the tibia or fibula, suture tape fixation either placed between two anchors or through a fixation plate if concurrent fibular fracture fixation is needed, can be substituted to provide direct anterior-based repair/stabilization. This is then combined with single syndesmosis implant system fixation for the posterior ring disruption (Figure 7).
Deltoid complex
It is the author’s opinion that while restoration of the congruity of the ankle mortise brings the fibers of the deep deltoid into approximation and thus allows for secondary healing of the deep deltoid ligament pathology, much akin to mid-substance disruption of the lateral ligaments, it is the superficial deltoid complex that frequently “peels off” of the medial malleolar bone, like a patellar sleeve avulsion of the knee that without surgical repair to the anterior colliculus leads to persistent elongation and instability of the associated fibers (Figure 8). This pathology, when present, is readily identified with the use of intraoperative arthroscopy. In addition to the ability to perform a “drive through” with a small joint shaver or probe (Figure 9), disruption of the anterior, superficial deltoid fibers facilitates the ability of a shaver or probe to communicate from the medial gutter around the colliculus and into the subcutaneous tissue of the medial ankle (Figure 10).
When recognized, restoration of the anterior superficial deltoid is critical to provide appropriate medial congruity of the talus within the mortise and prevent medial rotatory instability, and to also secondarily allow the deep fibers to maintain spatial continuity to heal appropriately. Although the exact sequence of soft tissue and bony repair is largely dependent on the preferences of the surgeon, it is the author’s preference to perform this only after fixation of the lateral osseous and ligamentous pathology. Through a separate, extensile exposure centered over the anterior colliculus, frequently, after incision through the skin, a subcutaneous traumatic disruption down through the capsule-ligamentous tissue is identified which not uncommonly extends back to the posterior tibial tendon sheath. Similar to a lateral ligament repair, this “medial Brostrum” is then performed by first preparing the bony bed and then, with suture anchors, advancing the tissue back to bone (Figures 11 and 12). This is most often accomplished with a suture bridge construct for two reasons: 1) biomechanical superiority of a double-row to single-row construct to resist forces with early mobilization; and 2) to provide maximal surface area contact of soft tissue to bone to facilitate healing.
Postoperative recovery considerations
In the acute postoperative setting, mainstays of early soft tissue healing focused on edema control measures with immobilization, and extremity elevation remains critical to facilitate early recovery and healing of the surgical wounds. As studies have shown regarding appropriate ligamentous healing, early motion to facilitate collagen formation along lines of tension while avoiding pathologic elongation are critical to functional regeneration of injured tissue. As such, with early wound healing, initiation of early active range of motion in the sagittal plane while avoiding inversion/eversion in the frontal plane is encouraged. Additionally, depending on the osseous and ligamentous injury involved, early progressive weight-bearing is encouraged, as well. Although custom molded casting can be used to safely encourage early weight-bearing while avoiding excessive strain on the soft tissues (particularly medially), lack of early motion can be detrimental to healing as discussed previously. With this consideration, use of fracture boot immobilization that can be removed to allow early joint range of motion and promote appropriate skin healing/hygiene is preferred. As current boot design allows for use on either extremity, arguably this is accomplished at the expense of arch and hindfoot support and control otherwise present in most athletic shoe wear, which can be critical in avoiding excess pronation and thus pathologic elongation and stress of the healing superficial deltoid and syndesmotic complex. To avoid this, it is recommended with early progressive weight-bearing protocols and particularly those involving repair of the syndesmotic and deltoid complex for the addition of an orthotic to the boot to provide support the medial hindfoot and midfoot.
Conclusion
Management of ankle trauma in the high-level athlete presents a complex scenario regarding diagnostic and treatment-related considerations. Although there have been significant developments in the surgical treatment of these various pathologies, complete understanding and recognition of the involved structures remains paramount to a clinically effective and expedient return to activity, as well as providing the potential to return to the preinjury level of performance.
- References:
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- For more information:
- Kirk A. McCullough, MD, can be reached at Kansas City Orthopaedic Institute, 3651 College Blvd., Suite 100A, Leawood, KS 66211; email: kmccullough@osmckc.com.
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Andersen MR, et al. J Bone Joint Surg Am. 2018;doi:10.2106/JBJS.16.01011.
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