Brostrom Procedure for Lateral Ankle Instability

The Brostrom procedure is a surgical repair of the lateral ankle ligaments, and it has been the gold standard treatment for chronic ankle instability for decades. Originally described in 1966, the operation directly reattaches the torn or stretched ligament tissue on the outer side of the ankle, and a common modification reinforces the repair with nearby tissue to add strength. Surgeons generally turn to it only after months of physical therapy, bracing, and strengthening exercises have failed to resolve the problem. The procedure’s track record is unusually strong for orthopedic surgery, with long-term studies reporting good or excellent results in roughly nine out of ten patients more than two decades after the operation.

Why the Lateral Ankle Ligaments Matter

The outer ankle is held stable by three ligaments. The one that tears most often during a sprain is the anterior talofibular ligament (ATFL), a relatively thin band that runs from the fibula to the talus bone. Below it, the calcaneofibular ligament (CFL) connects the fibula to the heel bone and provides a deeper layer of support. A third ligament at the back, the posterior talofibular ligament, rarely causes clinical problems on its own.

What makes the CFL so important is that it acts as a kind of backup. Cadaver studies show that cutting the ATFL alone does not produce a measurable increase in ankle inversion angle, but once the CFL is also cut, inversion angles increase and the joint becomes unstable under load, with peak torque dropping and pressure patterns inside the joint shifting.

¹ A separate biomechanical study confirmed this finding: sectioning the ATFL alone did not observably alter inversion angles, but subsequently cutting the CFL increased inversion in both the ankle joint proper and the subtalar joint beneath it.² The practical takeaway is that people who have injured both the ATFL and CFL tend to have worse instability than those who have torn only the ATFL, which is one reason surgeons assess both ligaments before and during surgery.

There is also considerable natural variation in ATFL size. Anatomical studies have found that the length, width, and thickness of the ATFL vary quite a bit from person to person, while the angle between the ATFL and CFL is a more consistent measurement.³ This person-to-person variation partly explains why some ankles tolerate repeated sprains without becoming chronically unstable while others do not.

When Surgery Becomes the Right Option

The consensus in orthopedic literature is clear: nonsurgical rehabilitation comes first. Strengthening the peroneal muscles, proprioceptive training, bracing, and activity modification resolve chronic ankle instability in many patients. Surgery is recommended when symptoms persist after three to six months of dedicated conservative treatment, the physical exam shows ongoing laxity on clinical tests, and imaging confirms the ligament damage.⁴ In practice, many patients go considerably longer than six months before seeking surgical consultation, often because they avoid the specific activities that trigger giving-way episodes rather than pursuing formal rehab.

Imaging before surgery typically involves stress radiographs and sometimes MRI. Each has strengths: MRI had a sensitivity of about 83% for detecting lateral ligament pathology in one study, while stress radiographs had higher specificity at 97%, meaning they were better at ruling instability in when present but less sensitive at catching all cases.⁵ Many surgeons use both in tandem and combine the imaging findings with what they feel during the physical exam.

What Happens During the Operation

The original Brostrom repair involves making an incision over the outer ankle, identifying the torn or stretched ATFL remnant, and reattaching it to the fibula with sutures. The goal is an anatomic repair, meaning the ligament is restored to something close to its original position and tension rather than replaced with a tendon graft routed through a different path.

The most common modification, attributed to Gould, adds a step: the inferior extensor retinaculum, a band of tissue that sits over the front of the ankle, is pulled up and sutured over the ligament repair as a reinforcing layer. This modification became so standard that “modified Brostrom” and “Brostrom-Gould” are often used interchangeably in clinical practice. The Brostrom-Gould technique is widely considered the gold standard for surgical treatment of chronic lateral ankle instability.⁶

Interestingly, a biomechanical cadaver study found no measurable difference in stability between the original Brostrom repair and the Brostrom-Gould modification when tested on the bench.⁷ One research group has suggested the retinaculum reinforcement uses a portion of tissue that has no real mechanical function on its own.⁸ Despite this, most surgeons continue to include the Gould reinforcement, reasoning that any additional layer of support during the vulnerable healing window is worth the minimal extra surgical time.

Open Versus Arthroscopic Approaches

Over the past decade, arthroscopic versions of the Brostrom have gained popularity. Instead of making a standard incision, the surgeon works through small portals using a camera and specialized instruments to reattach the ligament from inside the joint. The appeal is obvious: smaller incisions, the ability to inspect and treat the joint surfaces during the same procedure, and potentially faster early recovery.

A systematic review and meta-analysis of 11 studies covering nearly 700 patients compared the two approaches and found that by two years after surgery, there were no significant differences in functional scores, talar tilt, anterior translation, complication rates, or time to return to previous activity levels. The arthroscopic group did start bearing weight roughly a week earlier.⁹ A separate meta-analysis found a similar pattern: functional scores and pain were modestly better in the arthroscopic group during the first year, and the arthroscopic group reached weight-bearing sooner, but those differences narrowed over time.¹⁰

The arthroscopic approach is not without trade-offs. It requires specialized training, and the working space around the lateral ankle is tight. A cadaver study found that the superficial peroneal nerve passes close to the standard arthroscopic portal, with the nearest branch sitting an average of about 16 millimeters away.¹¹ That margin is tight enough to warrant caution, and nerve irritation or injury remains a recognized complication of the arthroscopic technique. For most patients, the choice between open and arthroscopic comes down to surgeon experience and the specific pathology found on imaging rather than any clear superiority of one method over the other.

Suture Tape Augmentation

A more recent evolution in the procedure adds a high-strength synthetic tape alongside the repaired ligament. The idea is that the tape acts as a seatbelt for the healing tissue, allowing the ligament to move and remodel under protection rather than being subjected to the full stress of ankle motion while it is still fragile. Biomechanical testing supports this concept: the suture tape augmentation construct tolerated about 95% more torque before failure compared to the standard Brostrom repair, and the ligament construct failed at a greater inversion angle with the tape in place (roughly 35 degrees versus 24 degrees without it).¹²

Clinical studies suggest that suture tape augmentation allows for higher early stability and reduced ligament elongation during the healing period.¹³ Additional biomechanical research has confirmed that the tape significantly improves the immediate post-repair stability of the ankle ligaments.¹⁴ Surgeons sometimes favor augmentation in patients who place higher demands on their ankles or in revision cases where the native tissue quality is poor. Whether the tape provides a meaningful clinical advantage over the standard repair in average patients remains an active area of study.

Recovery and Rehabilitation

The postoperative timeline varies depending on the surgeon’s protocol, whether the approach was open or arthroscopic, and whether augmentation was used. In a cohort of 67 patients, the average time to full weight-bearing in a walking boot was about four and a half weeks, and by six weeks roughly 88% of patients were weight-bearing. By twelve weeks, over 92% had returned to baseline activities in normal shoes.¹⁵

For competitive athletes, the return-to-play timeline is a bit longer. A study of elite athletes found that the average time to personal training was about two months, team training about three months, and competitive play about four months. All athletes in the study had returned to competition by eight months after surgery.¹⁶

There is an ongoing debate about how aggressively to mobilize the ankle after surgery. A meta-analysis comparing early mobilization (starting movement within the first two weeks) to delayed mobilization (immobilization for six weeks or more) found that early movers scored higher on functional outcome scales but had slightly greater residual laxity on stress testing and a higher complication rate, particularly for wound-healing issues (about 11% versus 3%).¹⁷ Return-to-sport timing did not differ between the two groups. This is a genuine trade-off, and the right protocol depends on the individual. A desk worker with no athletic ambitions might prefer the safer healing of a more conservative approach, while a younger athlete with good tissue quality might benefit from controlled early motion under close supervision.

One thing to be aware of is that even when patients feel ready to return to sport, subtle deficits may persist. Research has shown that dynamic balance and neuromuscular reaction time in the operated ankle remain reduced compared to healthy controls at the time patients are typically cleared for sports.¹⁸ This suggests that continued proprioceptive and balance training well beyond the formal “return to sport” date is important, and that the ankle may not be fully rehabilitated just because it feels stable on the field.

Long-Term Outcomes

The Brostrom procedure has one of the longer track records of any orthopedic soft-tissue repair, and the durability of the results is impressive. A study following patients for an average of 26 years after the original Brostrom procedure reported a mean ankle function score of 91 out of 100, and 91% of patients rated their ankle as good or excellent.¹⁹ Another long-term study found a mean functional score of 91, with 28 of 30 patients returning to their pre-injury activity levels.²⁰

In athletes specifically, outcomes at 10 to 15 years of follow-up were excellent in about 95% of cases, with functional scores jumping from an average of roughly 68 preoperatively to 99 postoperatively. All athletes in the study returned to their sport at the same competitive level.²¹ High-demand athletes using suture anchor fixation have also been shown to successfully return to their pre-injury functional level.²²

One concern worth addressing: the surgery does not appear to sacrifice ankle motion. A clinical evaluation found no significant difference in passive or active range of motion compared to the opposite ankle after the modified Brostrom repair.²³ This is one of the key advantages of an anatomic repair over older non-anatomic reconstruction techniques, which sometimes restricted motion, particularly eversion and subtalar movement.

Who Might Not Do as Well

The Brostrom repair works best when there is adequate remaining ligament tissue to sew back together. Factors traditionally considered as risk factors for a poorer outcome include severe pre-existing instability, poor quality or absence of the ligament remnant, obesity, and generalized joint hypermobility. That said, the evidence behind these risk factors is not as strong as you might expect; much of it is based on expert opinion and small case series rather than well-controlled studies.²⁴

When the procedure does fail, revision is possible but more complex. A case series of patients who failed a primary Brostrom-Gould repair found that the average time to revision was about 18 months, usually triggered by a new inversion injury. About half of the patients in that series required advanced imaging for a new injury after their revision surgery, though most of the reconstruction constructs remained intact on imaging. A small number needed further surgery to replace hardware or the graft itself.²⁵ For patients in whom the native tissue is clearly insufficient, surgeons may skip the Brostrom entirely and opt for a tendon graft reconstruction as the primary procedure.

Pre-existing arthritis in the ankle is another consideration. A study of patients who had both chronic ankle instability and early osteoarthritis inside the joint found that the modified Brostrom combined with arthroscopic joint debridement produced a low recurrence of instability (about 5%), but over a quarter of patients showed progression of their arthritis at follow-up.²⁶ Stabilizing the ankle did not necessarily halt the arthritic changes already underway, which is an important thing to discuss with your surgeon if you have both problems.

The Procedure in Children and Adolescents

Chronic ankle instability does occur in skeletally immature patients, and the Brostrom procedure can be adapted for them, though it requires extra care. The primary concern is the growth plate at the end of the fibula. Placing suture anchors or drilling near an open physis carries a theoretical risk of growth disturbance. Radiographic studies have shown that with careful preoperative planning and precise intraoperative technique, it is possible to safely perform the repair using suture anchors without damaging the growth plate.²⁷

Clinical results in young patients have been encouraging. A study of skeletally immature patients who underwent the modified Brostrom for subfibular ossicle excision and instability found dramatic improvements in pain, functional scores, and activity levels, with a median return to sports of 17 weeks. At final follow-up, there were no significant differences in leg length or ankle alignment compared to the opposite side, suggesting no growth disturbance had occurred.²⁸

More recently, arthroscopic “all-inside” techniques have been applied to pediatric patients. A study of 40 patients aged 8 to 15 who underwent arthroscopic ligament repair reported significant improvements across all outcome scores at an average follow-up of nearly four years. Postoperative MRI confirmed no cases of growth-plate violation, and no major complications, axial deviations, or clinical signs of growth-plate injury were observed.²⁹ These results are reassuring, though the evidence base in pediatric populations is still smaller than in adults, and most surgeons will exhaust conservative measures more aggressively in children before recommending surgery.