PATHOGENESIS
Colville described reconstruction of the lateral ligamentous complex of the ankle after a combined inversion-plantar flexion injury of the foot, which led to rupture of the ankle joint capsule, anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL)[8]. Brostrom, well known for his contribution to the diagnosis and treatment of ankle instability, found that 27% of patients evaluated for ankle injuries with ATFL disruption had concomitant CFL involvement. Fifty eight percent of these patients had increased inversion of the ankle when compared to the uninvolved extremity[9].
Advanced imaging may not be necessary in the evaluation of all patients with ankle inversion injuries but, when obtained, rarely show injury to the posterior talofibular ligament, even in the setting of ATFL and CFL disruption[10]. On the other hand, MRI evidence of ATFL disruption may not be clinically significant. MRI has proven useful in the evaluation of chronic ankle discomfort after recurrent ankle injuries, especially when attempting to identify associated injuries, such as osteochondral injuries or peroneal pathology. One should keep in mind, however, that a normal MRI does not preclude ankle instability.
DIAGNOSIS
Patients with ankle instability typically present for treatment after sustaining a severe twisting injury which has progressed to recurrent sprains. The severity of the injury has been linked to the clinical presentation, such that those patients who are unable to bear weight or return to sport immediately after the injury or have difficulty walking on uneven surfaces usually have, at the very least, a complete rupture of the ATFL[11].
Diagnosis is typically based on clinical findings and is made when there is increased laxity on anterior drawer and inversion testing compared to the contralateral ankle. An attempt to isolate rotational instability of the ankle helps to identify if there is an injury to the syndesmosis. Other findings in these high ankle sprains include inability to perform a single leg hop on the involved side, a positive squeeze test and pain with external rotation of the ankle. Some advocate the use of stress radiographs in the workup of ankle laxity, while others question the validity of this modality[12-19]. The use of the Telos device aims to more objectively quantify the degree of instability[16,17].
In order to ensure optimal results in treating patients with ankle instability, it is of utmost importance to identify and treat pathology that may be a result of, or lead to, ankle instability. Examples of associated pathology include osteochondral defects, peroneal injuries and neurological conditions leading to muscle imbalance. The heel should be examined for proper alignment because varus malalignment may lead to recurrent injuries after treatment, or failure of ligamentous reconstruction.
Most advocate conservative treatment for acute ligamentous injuries although there is some evidence that suggests that early surgical intervention leads to a lower incidence of chronic instability[3,9,20-22]. There is no reliable objective criteria that we are aware of that can be used to help dictate whether one will proceed to chronic instability after an acute injury. Once a patient does present with these symptoms after failure of conservative means, surgery should be considered. Such complaints in patients with high activity levels, when combined with positive findings on physical exam, may best be addressed with surgical reconstruction of the injured ligaments.
SURGICAL OPTIONS
The surgical treatment of lateral ligamentous injuries can be classified as either anatomic or non-anatomic reconstructions. Brostrom popularized an anatomic technique for the repair of ligamentous injuries, while Kalsson et al found that a delayed anatomic reconstruction was also possible[9,17]. These reconstructions aim at re-establishing continuity to both the ATFL and CFL through direct repair, which may further be augmented with an imbrication of the inferior retinaculum[23]. Longitudinal, transverse and oblique incisions have been described and selection should be dictated by any associated pathology[24]. Typically on gross examination a redundant and incompetent ligamentous complex is identified. The ligaments should be identified and directly repaired at a length that provides sufficient tension to stabilize the ankle.
Non-anatomic ligamentous reconstructions, such as the Evans, Watson-Jones and Chrisman-Snook procedures, have been described in the literature[10,25-32]. These procedures involve rerouting of a slip of autogenously harvested tendon to impart stability to the ankle and subtalar joint. Stiffness, arthritis and complications associated with tendon harvest have been attributed to these techniques, yet they may still have an important role in ligamentous reconstruction. Non-anatomic reconstructions may best be suited for those patients with long-standing instability, hypermobility or a failed anatomic repair[17].
Unlike the original technique described by Brostrom, our preferred approach to lateral ankle ligament reconstruction is to begin with an arthroscopic evaluation and treatment (Figure 1) of any intraarticular pathology, when indicated. This is undertaken with a 2.7 mm arthroscope and a low-pressure calf tourniquet. The joint and syndesmosis are inspected and articular injuries or intraarticular scar formation may be addressed. Any gross instability of the syndesmosis may need to be addressed with a separate stabilization technique, which is outside the scope of this editorial. When peroneal pathology is identified through a thorough preoperative evaluation, a posterolateral portal may be used for tendoscopy and tendon debridement or for a more thorough evaluation when the preoperative evaluation was equivocal. This portal may later be incorporated into a longitudinal incision for ligamentous reconstruction, which allows for treatment of any peroneal pathology in an open fashion.
Figure 1 Portal Placement and set-up for ankle arthroscopy.
SURGICAL TECHNIQUE
Our incision is dictated by other pathology and ensures exposure of the lateral ligamentous complex, inferior retinaculum and the peroneal tendons, if necessary (Figure 2). Dissection through the subcutaneous tissue is performed in line with the incision, protecting any branches of the superficial peroneal nerve when identified (Figures 3A and 3B). The ATFL, CFL and anterior joint capsule are identified, allowing for mobilization and retraction of the inferior retinaculum. Careful dissection is made at the level of the CFL in order to prevent injury to the peroneal tendons. The anterior joint capsule is then incised transversely, leaving a stump of capsule attached to the fibula for later repair. The ankle joint may now be explored if arthroscopy was not first performed.
Figure 2 Placement of a curved, anteriolateral skin incision between the superficial peroneal nerve and peroneals, just distal to the fibula.
Figure 3 Identification (A) and isolation (B) of a branch of the superficial peroneal nerve.
Reconstruction is then begun with placement of multiple, interrupted, nonabsorbable sutures in the capsule, ATFL and CFL, allowing for later sequential imbrication (Figure 4). The sutures are tied with the foot positioned in an eversion, followed by advancement of the inferior retinaculum over the imbricated repair (Figure 5), which is secured to the fibula with suture or suture anchor. A layered closure is then performed, followed by placement of a soft dressing and a supportive boot or splint.
Figure 4 Interrupted suture placement in the lateral ligamentous complex.
Figure 5 Imbrication of the lateral structures with a retinacular reinforcement.
Two hundred and fifty patients who underwent surgical reconstruction of their lateral ligamentous structures by a single surgeon between 1998 and 2008 were contacted for interview. Patients were included in the study if they underwent lateral ankle ligament reconstruction due to symptomatic instability with sporting activity and activities of daily living despite a course of conservative management. All patients had more than three instances of what they considered significant instability, with findings on physical exam that included ecchymosis, diffuse soft tissue swelling, pain along the course of the ATFL and CFL and an inability to bear weight immediately after the injury. The majority of patients in this study listed Australian Rules football, basketball, netball or soccer as the sporting activity during which the initial injury occurred. Patients with a varus heel alignment or peroneal weakness due to a neurologic condition were excluded from the study.
The most commonly encountered concomitant injuries at the time of lateral ligamentous reconstruction included intraarticular synovitis, hypertrophy of the ATFL leading to impingement and discrete osteochondral injuries. Any area of synovitis or soft tissue impingement was treated with arthroscopic debridement, while osteochondral lesions were generally small and amenable to debridement and osteoplasty.
The female to male ratio was 1:2, with a mean age of 34.47 (range 9-90). The patients were asked a series of questions in regard to postoperative pain and function, with 2.25% of patients admitting to residual pain. Two of these patients had a Brostrom procedure in conjunction with internal fixation of an ankle fracture. The remainder of the patients remain pain free at their most recent evaluation. The overall satisfaction rate was 91%.
The majority of patients denied continued instability, with 78% returning to activities without recurrence of inversion injuries. Of the remaining patients, 13% returned to a pre-injury level of activity with some residual instability, while 9% were limited in their ability to return to activity by continued instability.
The delayed reconstruction of the lateral ankle ligamentous complex is a well-established technique for the surgical management of ankle instability. The authors prefer an anatomic repair, with the addition of retinaculum advancement, as described by Brostrom and Gould[9,23]. Satisfactory reports have been described with the use of non-anatomic, tendon weaving repairs, but we feel that these techniques should be reserved for salvage cases due the associated complications, such as stiffness and sacrifice of a portion of the peroneals[25,26,28,30-32]. The peroneals are important stabilizers of the hindfoot and play a vital role in eversion of the foot and maintenance of the longitudinal arch. Harvesting of the peroneal tendons has been associated with loss of strength in approximately 8% of patients[33].
In order to ensure optimal results from ligament reconstruction, it is important to identify and address any factors that may predispose the patient to recurrent instability, such as varus heel malalignment and peroneal injuries. Other factors that may lead to poor results after surgical intervention include unrecognized concomitant pathology, such as articular cartilage injuries, unrecognised fractures, ankle synovitis or soft tissue impingement. In our experience, the addition of an arthroscopic examination aids in the diagnosis and treatment of these intraarticular conditions that may predispose patients to poor outcomes if not appropriately addressed.
In the current series, the most commonly encountered intraarticular injuries included areas of soft tissue impingement and osteochondral lesions. A recent study investigated causes for residual disability after ankle sprains in an attempt to compare the ability of arthroscopy to diagnosis pathology versus standard and advanced imaging[34]. The authors found arthroscopy to be as good in identifying intraarticular pathology as other imaging and able to identify missed lesions in 14 of 72 patients. Fifty-four percent of patients had ATFL injuries, 40.3% had osteochondral lesions and 4.2% of patients had impingement due to fibrous bands. Of those patients with impingement due to fibrous bands, arthroscopy was the only means of detecting the abnormality. A similar study in which arthroscopy was used to detect pathology in chronically unstable ankles found osteochondral injuries in 66% of patients and elongation of the ATFL and CFL in 86% and 64% of patients respectively[35].
Ankle inversion injuries continue to be a common condition, with a minority of patients progressing to chronic pain and instability. The diagnosis and treatment of this condition is well described, but the literature is limited to small series with limited follow-up. We present our experience with ankle instability in the form of disruption of the lateral ankle ligamentous complex in order to illustrate that good long term results can be anticipated in appropriately selected patients with an anatomic reconstruction, as long as all pathology is identified and addressed. The treating physician should be knowledgeable in terms of other injuries commonly associated with lateral ankle ligamentous injuries in order to properly evaluate and care for their patients.
COMMENTS
Background
Ankle sprains are among the most common musculoskeletal injuries seen by physicians. The majority of these injuries have satisfactory outcomes with the use of conservative treatments, but in the face of continued instability and patient limitation in spite of such intervention, surgical reconstruction of the lateral ligament complex may be warranted. In our experience, good long- term outcomes can be obtained with the use of an anatomic reconstruction of the lateral ligaments of the ankle.
Research frontiers
There has been some debate as to wether an anatomic or nonanatomic reconstruction of the lateral ligaments yields better results. Nonanatomic reconstructions have been associated with more hindfoot stiffness, and usually sacrifice a portion of the peroneals. There has also been some controversy in regards to the use of arthroscopy in the treatment of ankle instability, which we believe is an important tool, when used appropriately, in the treatment of chronic lateral ligament dysfunction.
Innovations and breakthroughs
Many researchers have found good short-term results with the use of an anatomic reconstruction of the lateral ligaments of the ankle. We have shown that the majority of our patients continue to have a high satisfaction rate at ten-year follow-up, with 91% returning to a pre-injury functional level. We also present the directed use of arthroscopy as an important tool in the treatment of concomitant injuries associated with chronic ankle instability.
Applications
The use of an anatomic approach to the reconstruction of the lateral ligaments of the ankle in our practice, when combined with an arthroscopic treatment of any intraarticular pathology, when indicated, has led to a high patient satisfaction rate.
Terminology
Lateral ligament complex: anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL). Modified Brostrom: Anatomic repair of the ATFL and CFL, with imbrication of the inferior retinaculum. Directed arthroscopy: Arthroscopic treatment of concomitant pathology identified preoperatively with a thorough history and physical exam, in conjunction with the use of appropriate diagnostic modalities.
Peer review
Overall, this was an interesting editorial on the author’s preferred treatment of ankle instability which will be of interest to readership.
