Chronic Ankle Instability: What to Do When A Sprained Ankle Won’t Heal

Most ankle sprains will heal with standard RICE therapy (rest, ice, compression and elevation) within two to 12 weeks. But for the patients with sprains that do not heal over time with standard therapy, both the cause and next steps for treatment can be unclear.

The indications that an ankle sprain has healed are almost as obvious as the initial signs of injury, reports Daniel C. Farber, MD, of the Penn Orthopaedics Foot and Ankle Service.

“The key sign of healing is stability with use—the patient’s capacity to put weight on the ankle confidently—without pain or the sense that the ankle is ‘giving away,’” explained Dr. Farber.

Ankle Injuries: Six Patient Profiles

According to Dr. Farber, “Non-healing ankle sprains are typically caused by discreet damage to the interior bones, cartilage and ligaments of the foot or at its junction with the tibia and fibula.” For this reason, and because these injuries may also involve entrapped fluid or impinging scar tissue, many reasons for persistent pain after ankle sprains are not apparent on X-ray.

In a recent video, through six patient profiles, Dr. Farber explains the physical and imaging diagnostics for each variant of ankle injury, the likely cause of injury, and the medical (or surgical) therapy for its resolution.

This video will also equip physicians with ways to identify the most common causes of persistent ankle instability, and provides guidance to identify the point at which further evaluation by an orthopaedic surgeon could be needed.

Dr. Farber’s patient profiles include:

• Snowboard Injuries: “Snowboarder’s Fracture”
  Snowboarding-related ankle injuries are more common than skiing injuries due to the increased range of motion that the snowboarding boot allows compared to a downhill ski boot. This patient suffered a less common ankle injury that is seen specifically in snowboarding and sometimes in soccer players called a “snowboarder’s fracture.” This is a discrete break in the talus bone at the subtalar joint of the foot. Best treatment often involves early surgery to avoid lasting pain and disability. (For an alternative sprain originating in bone injury, also see patient profile #5.) [Watch a video profile of a snowboarding injury]

• Cartilage Fractures: Post-recovery pain with strenuous activity
  This patient, who recovered quickly from the initial injury, but who continued to feel deep pain with strenuous activity well after the normal healing period, is suffering from a virtually invisible impact or shear fracture of the osteochondral surface on the talus bone. According to Dr. Farber, the best treatment is often arthroscopic debridement and cartilage stimulation procedures. [Watch a video profile of osteochondral surface injury]

• Ankle Ligament Injuries: Transient pain and post-recovery instability
  With a history of ankle sprain, this patient presented with pain and ankle instability months after a precipitating injury as a result of tearing of the ligaments near the ankle bone at the outside aspect of the foot/ankle. If the injury does not improve with bracing and therapy over time, the best treatment is surgical ligament repair. (For an alternative ankle sprain scenario, also see this patient, whose high ankle sprain was treated with long-term bracing). [Watch a video profile of ligament injury]

• Scar Tissue: Persistent pain that responds to steroid therapy
  Since this patient’s persistent pain at the outside of the ankle responds to local anesthetic and steroid therapy with minimal diagnostic imaging studies, it is likely the result of scar tissue resulting from an injury and now causing impingent in the ankle with bone movement. If the pain does not resolve with steroid therapy and time, the best treatment is surgical excision of the scar tissue via arthroscopy. [Watch a video profile of impingement injury]

• Tendon Injury: The patient with post-inversion sprain pain
  This patient has nagging pain at the side and back of the ankle months after an inversion ankle sprain. This pain is caused by torn tendons. If bracing and physical therapy does not resolve the ankle injury with time, the best treatment is surgery to repair the damaged tendons. (For an alternative ankle sprain originating in tendon injury, also see the this patient, whose damaged peroneal tendons at the rear of the foot were surgically repaired). [Watch a video profile of tendon injury]

• Peroneal Nerve Injury: The patient with pins and needle sensation months after ankle sprain
  This patient’s ankle sprain involved a stretch injury to the superficial peroneal nerve due to severe inversion and plantarflexion position of the ankle resulting in damage to the peroneal nerve at the front of the ankle. Best treatment, involving medications, expectations, and time, is based on accurate diagnosis. [Watch a video profile of peroneal nerve injury]

When To Refer a Patient for a Sprained Ankle

Dr. Farber's counsel to primary care physicians confronting protracted pain after an ankle sprain is to remember that an ankle sprain is still usually an ankle sprain “until it's not”.

“An ankle sprain that lingers beyond 3 months is often an injury to a bone, tendon or ligament that is unlikely to heal without intervention,” he says. “And the longer an ankle injury persists without proper treatment, the greater the likelihood that permanent disability will result.”

In other words, Dr. Farber concludes: Once it’s clear that ankle sprain is complicated and not resolving with the usual treatments, the best recourse is a referral to a qualified orthopaedic foot and ankle surgeon.

Video Transcript

View the full transcript (PDF)

The way I put this together was to have a couple of different scenarios that go over some of these potential injuries.

Scenario #1 is a 20-year-old female. She injured her ankle snowboarding about six weeks ago. She was seen by the ski patrol on the hill, told that she just had a sprain. She used a lace-up ankle brace for a couple of weeks but really continues to have a lot of pain, especially along the anterolateral aspect of the ankle, and especially when the ankle is really everted and rolled out to the side.

Here's a potential scenario where the snowboarder gets injured. You can see her coming down the hill in her best form, coming off a little jump, and, boom, she hits the ground. The foot tends to dorsiflex and evert and creates this injury that you see here. What you can see subtly on the X-ray is this little abnormality here along the lateral aspect of the talus. This is commonly referred to as a snowboarder's fracture. On a CT scan, it becomes much more clear that, as the calcaneus comes up, it kind of hits against the fibula, it nutcrackers this little fragment here and breaks it off. This is part of the joint, of the subtalar joint, so it's an important fragment.

It's a dorsiflexion eversion mechanism. That nutcracker effect happens on the talus. This can be very easily missed because, on regular ankle films, it's not always as clear as the X-ray that I showed you. A CT scan will show it but you have to have the suspicion and the knowledge that this might be an injury in order to even pursue a CT scan.

The importance of this injury is that it's much better to treat this early surgically. If it's a really small fragment, you can sometimes treat this with nonoperative care, but a lot of times, especially with athletic patients who are very active, if this is a small fragment or it's broken into a lot of little pieces, they do much better with early excision. If it's a significant fragment, they'll do better with fixing this.

This is a patient of mine from a couple of years ago. You can see this is a pretty large articular surface fragment that's fractured. Then, you'll see in this image here, the peroneal tendons, running right in this area. This is the lateral ankle here, so this is the front of the ankle. You can see the two little screws here that we used to fix this into place.

Scenario #2 is a 22-year-old male basketball player. Sprained his ankle about six months ago. He recovered fairly quickly but the ankle has never quite felt right, never 100%, and it bothers him a lot with strenuous activity. The pain is sort of deep in the ankle. Doesn't have any instability, doesn't really have any pain day to day, but, when he's trying to play sports, this is still limiting him.

Here's a potential injury of the ankle. You'll get a little close-up. Look at #50 there as he comes down and rolls his ankle. If you watch a little linger, you get this close-up view. As his foot comes down, you see that rolling mechanism of the ankle. That's a classic eversion ankle sprain injury while playing basketball that we see quite commonly.

His X-rays are pretty normal. You don't see any fractures or any clear abnormalities but, because he's now gone a number of weeks with persistent pain, he got an MRI scan. Here, you see this edema within the bone along the medial talus. This is consistent with an osteochondral injury of the talus. What's happened is basically a shear sort of fracture of the cartilage. Then, you get this fluid that gets pushed down into the bone. This can be a significant source of pain.

This is often a delayed presentation because, usually, we expect these to get better. I think a lot of minor osteochondral injuries do happen with these injuries but they get better on their own and don't need any additional treatment other than the standard treatment for an ankle sprain. Again, these patients, usually day to day living, this is not a big deal, but it's when they try to ramp up to more strenuous activities that they can't get back there.

The pain is often poorly localized. They kind of just feel it deep in the ankle, and it doesn't always correlate. If they feel the pain on the inside part of the ankle, they can still have the lesion on the outside part of the ankle. It's pretty classic that they're very bad at localizing where the injury is.

X-rays are often negative. Sometimes, you can see some lucency in the talus that suggests there's an injury there but, in more acute injuries, it's often very hard to see, so MRI or CT scan can be very helpful.

In younger patients, a period of casting can be helpful to get this to heal. In older patients, and I'm not talking that old, but really past adolescence, oftentimes surgery is necessary to clean out the area of cartilage injury. We'll often drill into the bone in that area to try to stimulate the body to form some scar cartilage over that region.

This is an arthroscopy. What you can see here is this is a flap of cartilage that's coming up from the normal cartilage surface here. That's part of that cartilage injury. What we've done now is we've basically cleaned out that loose cartilage. Now, we have a stable edge of cartilage. Here is exposed bone. This is a significant injury, where you lose cartilage.

We then drill into the bone and what we want to see is this little bit of bleeding here. That's those good marrow elements that have a lot of stem cells and multi-potential healing cells that can form some scar cartilage over this whole area so that at least that joint has a better gliding surface. That seems to help very well in most patients.

Scenario #3, a 32-year-old female with multiple prior ankle sprains. Her last sprain was about eight months ago. She has persistent pain and swelling, doesn't trust her ankle. She avoids sports. She has several episodes of giving way over the past six months.

You examine her in the office, and this is just the textbook image that we saw earlier. Again, you see this sort of dimple sign. There's clear anterior instability. A patient who continues to be unstable at this stage, with giving-way episodes, they will often benefit at first from a course of physical therapy if they haven't had that already. That's really to focus on proprioception and strengthening of the surrounding musculature to see if that can be adequately ... Sorry, to see if that can adequately restore their sense of stability and allow them to return to activity. These patients often need bracing for more strenuous sporting activity to give them the sense of stability that they need.

If those things fail, then surgery to repair the ligament is often very helpful. This is a diagram of the classic Brostrom-type repair. This is the fibula right here. This is the calcaneofibular ligament, which has been cut and shortened and repaired. You don't always actually have to repair this. The most important part is repairing what's called the anterior talofibular ligament. That ligament is actually underneath here. This is the extensor retinaculum, which holds down the tendons on the front of the ankle. We incorporate that into the repair for some additional stability. Underneath that is the ligament repair.

That's very successful surgery. People do very well with that and they're able to return to most sporting activities, but it does take about six months before they can go back to real strenuous activity.

Scenario #4 is an 18-year-old football player who twisted his ankle on the turf about a month ago. They did rest, ice, compression, elevation, and told him he'd be better in a couple weeks because it didn't look like that bad a sprain but he continues to have significant pain, pointing to the anterolateral aspect of the ankle. The pain travels up the leg from that point.

X-rays are negative, but an MRI shows this fluid right here in the recess of the syndesmosis. This, as we talked about earlier, is a syndesmotic injury, or your classic high ankle sprain. This is the injury to the syndesmotic ligaments that connect the fibula to the tibia, and so, when the ankle externally rotates, that's what puts stress on these ligaments.

You can diagnose this with what's called a squeeze test where you squeeze the fibula against the tibia proximally in the leg, just below the knee. That should recreate pain at the ankle. People often complain of pain over the tibia where you put your hand or your thumb. That's not a positive test. It has to be pain that they feel down in the ankle.

The X-rays will be negative unless there's severe ligament disruption and instability. That's a different sort of injury.

These take a long time to heal. They need a good bit of bracing for a while and rehab, and mostly time, but they will almost always settle down.

Scenario #5 is a 38-year-old female. She sprained her ankle about nine months ago. She got better for a while but has pain in the anterolateral ankle. No instability. She did some therapy, which didn't help, but she did get a cortisone injection in the ankle and that seemed to give her excellent relief for a period of time.

This scenario, this is really a diagnosis of exclusion until you get to this point. This is an arthroscopic image of the ankle. Patients can develop what's called an anterolateral impingement lesion. What that is is essentially hypertrophic scarring of the lateral ankle ligaments or the capsule. That creates, essentially, an impingement lesion where, when the ankle dorsiflexes and comes up, this excess tissue that you see here in the ankle. Here is the talus and up here is the tibia. When these two bones come together during activities, or even just walking, it pinches all this tissue here and causes pain.

These patients respond very well to excision of this tissue, but oftentimes they'll get better with time or with a local cortisone injection. MRIs are not very helpful. They often don't show this lesion. We're looking at some research to see if ultrasound may be more helpful in finding these lesions, but sometimes it's simply a diagnosis of exclusion. You've ruled out all the other things, their pain is appropriate and clinically appropriate to this sort of diagnosis, and you offer them an arthroscopy. That will often solve the issue for them.

Scenario #6 is a 42-year-old female. She turned her ankle stepping off a curb about six weeks ago. They placed her in an air stirrup in the ED but that didn't really help. Her bruising and swelling has resolved but she continues to have a lot of pain over the lateral foot and ankle.

Here are her X-rays. What you'll notice here is some abnormality at the base of the fifth metatarsal. The point here is you always need to check the foot when people have an ankle sprain and turn it because you can sometimes end up with a fracture of the fifth metatarsal. This is indeed a Jones fracture, and it is an area of the bone that sometimes doesn't heal very well, my point being here is that you just need to make sure you examine this as a possible source of their injury.

Treatment is often casting or a CAM boot. Most avulsion-type fractures will heal very readily. The Jones fracture, like we see in this image here, often gives us trouble healing, and so, especially in athletic patients, we'll consider putting a screw down the pike here to get this to heal more quickly. Here is an example of that where you see the screw crossing the fracture line. This, again, helps to get this to heal much more quickly.

Scenario #7 is a 36-year-old female. She suffered an inversion ankle sprain about six months ago. She's done well except she has this nagging posteriolateral ankle pain and swelling and sometimes popping. Worse with activity. She uses a lace-up brace, which makes her feel better for activity, but this is still a significant problem for her.

This is a scenario where we can have some injury to the peroneal tendons. This is an MRI image, axial image. This is the fibula here, tibia is here, and these are the peroneal tendons running behind there. You can see these tendons should be restricted back here. They should be back behind the fibula. This one is subluxating out to the side. In that setting, that instability can cause pain. It can also cause a tear to that tendon.

This is an injury to the superior peroneal retinaculum. It can be simply a shift of the tendons. It can also be a tear in the tendons. Exam is very helpful to look for subluxation. If you have their foot in a plantar flex position and a little bit eversion and you ask them to push against the side of their foot, you'll sometimes feel those tendons shift out of position. MRI or ultrasound can be very helpful for diagnosis.

For a tear, sometimes therapy and bracing is adequate to take care of this. If it doesn't resolve, then surgery to clean out and repair the tendon is helpful. If it's subluxation of the tendons and they really pop out next to the fibula, therapies are often not successful because it doesn't help to restrain the tendon where it needs to be, and surgery to repair that retinaculum is quite helpful.

Scenario #8 is a 46-year-old male who sprained his ankle falling on the stairs and has a hyper-plantar flexion injury, as well as inversion. He now complains of pins and needles sensation in the dorsum in the foot, hypersensitivity over the top of the foot, and sometimes the pain will radiate up the anterolateral leg.

In this setting, this is what we often see, is an injury to the superficial peroneal nerve. You can see the branches of the superficial peroneal nerve. They cover the sensation over the entire top of the foot. You can see in this diagram, this whole area is covered by this single nerve. When you turn the ankle, this nerve gets put on tension and you can have a traction injury.

If you look closely at a lot of ankle sprains that you see, in the first few days, and sometimes even a few weeks, they'll have irritation of this nerve, but it often quiets down. It's a little bit more rare that this pain persists for a longer period of time. You can see this on a regular patient just by surface anatomy. You can see the course of that superficial peroneal nerve right in this area. It's a very superficial nerve, very susceptible to injury.

This will get better with time. The most important thing that you can do is to diagnose this properly so you can let patients know that they will get better, it's just going to take time. Most of the time, the nerve recovers, but it can take a number of months. If they're really having a tough time, using some neuroactive-type medications, whether that be Nortriptyline or Gabapentin or Cymbalta or similar things like that to help attenuate the nerve pain, can be helpful.

In summary, an ankle sprain is usually an ankle sprain, but sometimes it's not. If it doesn't get better, you want to further investigate this, both by physical exam, as well as diagnostic tests. It can be any of these diagnoses that we've talked about today, and there's even more, but I won't torture you with all the additional information there.
I want to thank you very much for your attention. It's been an honor to have the opportunity to speak with you. Thank you.