Ankle Instability (Chronic Ankle Sprains)
Ankle sprain simply means tearing of the collateral ligments that stabilize the ankle and prevent it from giving way. The ligament damage can be as mild as stretching the tissue or as severe as completely tearing the tissue in half. Fortunately, most patients who have an ankle sprain recover with rest, ice, compression, elevation, anti-inflammatories, bracing, and physical therapy. The physical therapy component helps to strengthen the peroneal tendons and also emphasizes balance and proprioception to prevent future sprains. Even patients with complete tearing of their ankle ligaments often recover completely and are able to continue life with the activities they enjoy without the need for surgical intervention. In fact, studies have shown that conservative treatment and surgery both have equivalent outcomes for the treatment of an acute ankle sprain.
Unfortunately, some individuals with a severe sprain or recurrent sprains may develop laxity and instability in their ankle. This can lead to chronic ankle instability. Ankle instability is a problem most often seen in young patients or athletes with multiple ankle sprains or the feeling that their ankle is unstable and gives way frequently. Symptoms may include pain, giving way, difficulty walking on uneven ground, cracking and popping, or recurrent sprains. Diagnostically the physician may be able to shift or subluxate the ankle which can be indicative of chronic instability. Sometimes these patients respond to activity modification, bracing, and physical therapy. If these modalities have been attempted, and the chronic instability persists, then an operation may be warranted. The operation generally consists of primary repair of the ankle ligaments commonly referred to as a Brostrum procedure. Many patients have insufficient healthy tissue for primary repair. In those instances, the surgeon may use a donor tendon (allograft from a donor person, or autograft from yourself) to pass through bone tunnels to recreate and reinforce your torn ligaments with a more robust repair.
In individuals with recurrent episodes of instability other portions of the ankle can also become damaged including the articular cartilage surface and the peroneal tendons. For this reason, simultaneous to your ligament repair, the surgeon may perform additional procedures including an ankle arthroscopy to remove inflammatory synovial scar tissue and to address any damage to your articular cartilage. This can include removing loose pieces of cartilage and bone (loose bodies) from your ankle or drilling holes in the bottom of cartilage defects (osteochondral defects- OCD) to stimulate bone marrow to backfill the OCD with new scar cartilage. Drilling the articular cartilage to stimulate backfill with bone marrow is a procedure known as 'microfracture'. In patients who have already attempted microfracture or who have very large OCDs, then exciting new products exist to help restore the cartilage defect. Two of the cartilage products approved by the FDA in the United States include BioCartilage (Arthrex, Naples, FL) and DeNovo (Zimmer Warsaw, IN). These products are very expensive and generally only approved by insurance companies after other procedures have been attempted. Individuals with recurrent sprains also often have concomitant peroneal tendon tears. These tears can cause pain in the ankle directly behind the fibula bone. Tears may severely limit the function of the peroneal tendons which are important for preventing future ankle sprains. For this reason, often times the peroneal tendons will be evaluated and repaired if necessary at the time of your ankle ligament reconstruction.
If you have unsuccessfully attempted conservative treatment for chronic ankle instability, then you may benefit from a reconstructive operation. Your work-up prior to surgery will include injury history, physical exam, x-rays, and likely an MRI to evaluate the peroneal tendons, ankle ligaments, and the articular cartilage. A CT scan is also sometimes necessary to help measure the true size of an OCD.
The recovery from chronic ankle instability surgery is variable and dependent on patient characteristics as well as surgical findings. The surgery is generally done on an outpatient basis. You will be discharged with a prescription for pain medicine to help control your pain. Many patients choose to have a nerve block placed prior to discharge to help decrease any discomfort. Much of the time immediately after surgery is spent resting and elevating your leg to decrease swelling, which will enhance incision healing and decrease the risk of infection. We generally recommend you keep your leg elevated as much as possible during the first two weeks. Your ankle is usually immobilized for 6 weeks to promote healing. Depending on what is found at the time of surgery, most patients are not able to put weight on the ankle during the first six weeks and will need to use crutches, a walker, or a rolling knee walker to aid in mobilization. You will be discharged home in a splint and then we will see you in office within the first week to check your incision and place a cast. At three-weeks, sutures are usually removed and a new non-weight bearing cast is placed. Typically, at six weeks following surgery, the cast is changed to a walking boot. Patients wear the boot for about 6 weeks as they gradually transition back to weight-bearing and begin motion exercises. Typical office visits are at 1 week, 3 weeks, 6 weeks, 12 weeks, and then less frequently. Physical Therapy is an important component of recovery from chronic ankle instability surgery and is usually commenced at 6-12 weeks.
© 2015 Jesse F. Doty, MD - Reviewed: October, 2015
Dr. Doty is a foot and ankle fellowship-trained orthopaedic surgeon with an interest in providing musculoskeletal care to the lower extremity. Subspecialty training equips him to confidently address some of the most complicated deformities of the foot and ankle. He is well-versed in internal fixation as well as external fixation in treating chronic hindfoot and forefoot deformities.