Clinical evidence supports anatomic reconstruction for ankle instability

Broström technique gives consistent results proven over time.

Issue: June 2008

ByBrian C. Toolan, MD

Brian C. Toolan, MD
Brian C. Toolan

In the management of ankle instability, the best surgical option becomes apparent when you consider the anatomy, biomechanics and the pathology associated with an unstable ankle. The clinical evidence clearly demonstrates that a Broström repair provides the best results. When you add these factors up, it makes sense to proceed with anatomical reconstruction for the treatment of mechanical instability.

Ankle instability is defined as abnormal anterolateral rotatory motion of the talus. Specifically, the talus internally rotates, anteriorly translates and adducts in the mortise during weight-bearing activity.

Clinically, instability has to two components: mechanical and functional. The mechanical component derives from quantifiable ligamentous laxity and the functional component from subjective, dynamic dysfunction of the joint. Mechanically, instability has to do with the patient experiencing giving way and having traumatic events which invert the joint and less to do with experiencing pain and unreliability. The converse is true with functional instability.

Static and dynamic factors

Several factors provide stability. The articular congruence between the talus, tibial plafond and the fibula and the application of weight to load the joint provides stability. These articulations are maintained by the lateral collateral ligaments: the ATFL (anterior talofibular ligament) and the CFL (calcaneofibular ligament). Each ligament contributes a varying amount of restraint to abnormal motion throughout ankle range of motion.

It is important to note that these ligaments are not identical structures orientated approximately 105° from one another. They have different mechanical properties. The CFL is 2.5- to 3-times stronger than the ATFL when loaded-to-failure. The ATFL elongates much more than the CFL before failure. These two ligaments effectively complement each other to provide stability during gait.

Dynamic factors include proprioception and peroneal tendon function. The strength and reaction time of these tendons are essential to ankle stability. Studies have shown that deficits in peroneal strength and reaction time impair proprioception and the stability of the joint.

Clinical evidence

Clinical evidence supporting an anatomic reconstruction for mechanical instability began with Broström’s work in 1966 describing a midsubstance repair of the ATFL. In this retrospective review (level IV evidence) he reported that his procedure restored stability in more than 85% of the cases. Gould added valuable modifications to the anatomical reconstruction by repairing the CFL and lateral talocalcaneal ligament and by using the extensor retinaculum to augment the ligament reconstruction. Gould demonstrated success with early and late repair (level IV evidence) in patients with mechanical instability using his modifications.

Karlsson (level IV evidence) performed a large series of anatomical reconstructions with imbrication and reinsertion of the ATFL and CFL into a bony trough. At an average follow-up of 6 years, he reported 86% good or excellent results. He also identified a relationship between persistent laxity and functional outcome. When he performed radiographic anterior drawer and varus tilt tests postoperatively he found that increased translation negatively correlated to the outcome; patients who demonstrated persistent laxity had worse outcomes. Of the 20 patients who had clinical failures, 15 had evidence of hypermobility or hyperlaxity. Of the 20 patients who had clinical failures, 15 had evidence of hypermobility or hyperlaxity in the joint.

Hamilton had good results with a Broström-Gould repair in 28 patients of whom more than half were dancers. He had excellent results in all the dancers included in his study. Overall, Hamilton had no failures, did no redos and no complications in this retrospective case series (level IV evidence).

The longevity of the Broström procedure was investigated by Bell. He retrospectively assessed patients (level IV evidence) with a questionnaire that revealed excellent subjective results at an average follow-up of 26 years.

Thermann assessed his results (level IV evidence) with a clinical algorithm for the operative treatment of ankle instability. Although patients who underwent an anatomical repair had 90% good or excellent results, he found that the postoperative stress radiographs of the ankles were not as stable compared those that underwent an Evans procedure. However, he observed a significant loss of hindfoot inversion in patients reconstructed with the Evans procedure and no deficit in the range of motion in the Broström group. Based on these results, Thermann concluded that the Broström procedure with or without a periosteal flap to augment the reconstruction was the first choice in his treatment algorithm except in cases of ankle arthritis or absent tissue for repair.

Nonanatomic drawbacks

There are several shortcomings associated with a nonanatomical tenodesis for the treatment of ankle instability. They all relate to the lack of a direct repair of the ATFL, the CFL or both during the reconstruction. These tenodesis procedures attempt to stabilize the ankle at the expense of motion or they avoid overtightening the joint at the expense of persistent instability.

Several studies have compared the Broström head-to-head with tenodesis. Hennrikus compared the Broström to the Christian-Snook procedure in a prospective randomized controlled trial (level II evidence). The patients with the Broström had higher outcome scores and more excellent ratings overall than those who received the tenodesis. The Christian-Snook patients had more problems with nerves, wound healing, and complained of their reconstruction being too tight in the postoperative follow up.

In a series of level III studies evaluating patients for more than 20 years, Crisp found that the results with a tenodesis worsened in the long-term. He found increased levels of pain, complaints of stiffness and instability in these patients along with higher rates of revision and ankle osteoarthritis.

As surgeons, have moved away from the classic tenodesis procedures and on to anatomic tenodesis such as those described by Colville and Solakoglu. They have been able to demonstrate that they can preserve near-normal range of motion in ankle. However, all these newer techniques emphasize the importance of placing and tensioning the graft properly to ensure the success of the reconstruction. Thus, it appears that these anatomical tenodeses minimize the chance of overtightening the joint and creating excessive ankle stiffness, but a demanding level of technical expertise is required to reach these claims of improved functional outcome.

Simple and anatomic

The Broström is a direct, simple and anatomically based repair for mechanical instability without the expense of losing ankle or subtalar motion. Over the course of time, is the Broström has proven to be a versatile procedure. There have been two significant modifications that have allowed surgeons to deal with soft tissue deficits. The Broström procedure is also versatile in regard to patient lifestyle — dancers, elite or recreational athletes and people with a pedestrian lifestyle, can be treated successfully. It has demonstrated long-term durability with few postoperative complications.

Based on consistently positive results in a broad series of level IV studies, the use of an anatomical ligament reconstruction as the primary procedure in the surgical management of mechanical instability warrants a grade B recommendation. When judging the Broström versus a tenodesis, the studies mentioned above justify a grade B to B+ recommendation for the Broström

In cases of poor or absent tissue preventing an anatomical reconstruction, long standing laxity, previous attempts at surgical repair, generalized ligamentous laxity and hindfoot varus, the Broström procedure may not be the best option.

For more information:
Brian C. Toolan, MD, can be reached at 5841 S. Maryland Ave., MC 3079, Chicago, IL 60637; 773-702-6984; e-mail: btoolan@surgery.bsd.uchicago.edu. He has no direct financial interest in any products or companies mentioned in this article.

Reference:

Toolan BC. Broström anatomical repair. Presented as part of the Ankle Instability Debate at the 38th Annual Winter Meeting of the American Orthopaedic Foot and Ankle Society. March 8, 2008. San Francisco.