Surgical Complications

Edited by John Early, MD 

There is no operation that has ever been invented that does not have the potential to make a patient worse.

Surgery has the potential to improve the lives of many patients. However, there are inherent risks that are involved with ANY surgical procedure. For patients thinking about surgery, it is important to discuss with your physician what outcome you can reasonably expect as a result of your surgery. It is also essential to understand the risks and potential surgical complications associated with your particular procedure.

Asymmetric Gait

While recovering from foot surgery, patients invariably walk with an uneven gait that will cause extra loading on other parts of the body (most often the back and occasionally the hip or knee on the opposite side). This change in normal gait may lead to irritation to tendons, muscles, and ligaments, which can become painful. The symptoms associated with an uneven gait usually go away after the gait has normalized. Symptoms that result from an uneven gait can be helped by focused stretching and core strengthening exercises as directed by your surgeon during the recovery time. In addition, patients should consider using crutches, a cane, or a knee walker rather than walk with a markedly asymmetric gait.

Complex Regional Pain Syndrome (CRPS)


Complex Regional Pain Syndrome (CRPS) is a serious post-operative complication characterized by marked pain, and often out of proportion to the clinical findings. In the past, it was known as Reflex Sympathetic Dystrophy (RSD). Fortunately, CRPS is not a common complication. However, when CRPS does occur, it can create significant ongoing leg pain. These symptoms need to be treated early and aggressively, in order to minimize the potential for long-term problems.

Clinical Presentation

Complex Regional Pain Syndrome (CRPS) is a neurological syndrome characterized by:
  • Severe burning pain
  • Pathological changes in bone (often a washing out of calcium from the bone)
  • Pathological skin changes (such as dramatic color changes)
  • Excessive sweating
  • Tissue swelling
  • Extreme sensitivity to touch (difficulty having even bedsheets touch the involved area is a common finding)

CRPS is best described in terms of an injury to a nerve, soft tissue or bone (e.g. a fracture) that does not follow the normal healing path. When CRPS occurs, the sympathetic nervous system seems to assume an abnormal hyper-excited state after the injury. The sympathetic nervous system is the part of the nervous system that is involved in the "fight or flight" response. It provides a "control" function for the organs and tissues of the body. For example, it helps control the diameter of blood vessels which can control how much blood is flowing to each area of the body.


CRPS does not appear to depend on the severity of the injury. Minor injuries can lead to CRPS while many severe injuries often do not create any abnormal sympathetic response. There is no single laboratory test to diagnose CRPS. The physician must assess and document both subjective complaints (medical history) and, if present, objective findings (physical examination) before making the diagnosis. Because CRPS is a serious condition, making such a diagnosis should not be done without serious consideration and significant expertise on the part of the physician. Therefore, a diagnosis of true CRPS is often best left to a physician with extensive experience (often a pain medicine specialist).


CRPS will often start as a localized nerve injury (neuritis). In CRPS, all of the nerves innervating the foot tend to become excessively "excited." This is not only painful, but also creates a marked increase in blood flow to the foot as the sympathetic nerves cause the blood vessels to dilate. This can produce impressive blanching of the skin when it is touched (Figure 1). This blood flow leads to swelling and warmth in the foot, as well as the tendency to resorb the calcium in the bone leading to excessive local loss of bone mass (osteopenia). It is also the reason why a bone scan will show an intense "lighting up" in the foot of a patient with CRPS, as this is consistent with the marked increase in local blood flow.

Figure 1: Blanching of the skin from dilated blood vessels (Dermatographia)


Treatment of CRPS needs to be started early and should be aggressive. If a significant local nerve injury (neuritis) or a complex regional pain syndrome (CRPS) is diagnosed, a referral to a pain medicine specialist may be warranted. Treatment may involve:

  • Physical therapy aimed at addressing a local neuritis (nerve irritation): This can include "desensitization therapy" where the area around the injured nerve is massaged. This is usually uncomfortable. Though the therapy can make the symptoms worse in the short-term, it is essential to get the nerve to settle down. In addition, physical therapists will continue to work on maintaining joint motion.
  • Nerve stabilizing medication: Medications such as gabapentin (Neurontin) may be started in an effort to get the nerve symptoms to settle.
  • Local Lidocaine patches: Local anesthetic patches applied to nerve injuries can often improve a patient's symptoms, and perhaps stop the pain cycle that can lead to a full blow CRPS.
  • Sympathetic blocks: Blocking the sympathetic nerves at the level of the spine can help improve the symptoms associated with CRPS. These are performed under x-ray guidance by physicians with expertise in these types of blocks.
  • Anti-depressant medications: It is not uncommon for patients to benefit from a course of anti-depressant medications to help break the cycle associated with CRPS.
  • Vitamin C: There are some studies that suggest that taking vitamin C daily before and after surgery may minimize the risk of developing CRPS.

Deep Vein Thrombosis

A DVT (Deep Vein Thrombosis) is a blood clot in the lower leg veins, which are the veins that help carry blood back to the heart. It is a relatively uncommon, but potentially serious complication of foot surgery. Symptoms of a DVT range from no symptoms at all too marked swelling and discomfort of the lower leg. Having a blood clot in the leg is a worrisome problem because it can lead to a pulmonary embolism. A pulmonary embolism occurs when a blood clot forms and then breaks away and goes to the lungs, where it can be fatal.

Patients who have had significant blood clotting in one of their legs may suffer from chronic swelling and engorgement of that leg. This is a condition known as post-thrombotic (or post-phlebitic) syndrome. Risk factors for a DVT (Blood clot) include the three elements described by Virchow in the 1800's:

  1. Stasis (blood that does not move freely) such as may occur in a patient who is immobilized on the operating table for a while, or someone who is immobilized in a cast. In both instances, normal lower extremity muscle contracting is diminished, and this decreases normal venous blood flow.

  2. Hypercoagulability of the blood (easy clotting). There can be an inherited tendency for increased blood clotting, so a positive family history of a blood clot may be important.  Also smoking, the use of birth control pills, and the presence of certain cancers, can increase a patient's potential to form blood clots.
  3. Endothelial (blood vessel) injury. Trauma or surgery may increase blood vessel injury, which in turn can increase the chance of blood clots forming. 

 Based on Virchow's Triad, the risk of having a blood clot in the leg is increased with:
  • Immobilization
  • Direct injury to the vessel
  • Obesity
  • Birth Control Pill or other hormone use
  • Positive family history (first-degree relative)
  • Previous history of a blood clot (perhaps the most important risk factor)

Prophylaxis against blood clotting can include: mechanical devices to squeeze the lower leg muscles when patients are anesthetized, or thinning the blood with medications.


Unlike major surgery on the hip and knee, symptomatic blood clots after foot surgery are relatively uncommon without a major risk factor: The risk of a blood clot is about 1 in 100. Using medication to protect against blood clot formation may increase the risk of bleeding. This bleeding risk can increase the risk of wound healing problems and infection. For this reason, many foot surgeons do not routinely give blood thinners following foot surgery if there are no major blood clotting risk factors.

Failure to Resolve ALL Symptoms

Some pain may still be present even after a successful foot or ankle surgery. It is important to appreciate that there are MANY different potential sources of pain in the foot and ankle. Operations on the foot and ankle are usually designed to address pathology (and the resulting pain) from specific areas of the foot. A successful surgery on one area of the foot may have no effect on pain originating elsewhere in the foot or ankle.


For example, an ankle fusion or ankle replacement may eradicate most or all of the pain symptoms stemming from an arthritic ankle joint. However, these procedures will have no appreciable effect on symptoms that are originating from ligaments and tendons outside of the ankle joint, or arthritis that involves any of the surrounding joints. In fact, arthritis in the surrounding joints, such as the subtalar and talonavicular joint, may actually be worsened following an ankle fusion.


Serious deep infection following foot surgery is not common. About 1 in a 100 (or less) patients experience this complication following a surgical procedure. Re-hospitalization and intravenous treatment may be required to treat a serious post-operative infection. People with diabetes, smokers, and those who have had a previous infection in the area, are at a higher risk of developing an infection..

Nerve Injury / Neuritis

Numbness over the incision is a common occurrence following surgery. However, it is a more serious problem if a nerve that affects muscle or sensory control is injured. This can occur when a nerve is placed under traction, or when it is directly injured. The risk of nerve injuries varies widely, depending on the particular operation. Therefore, it is important for any patient contemplating foot surgery to discuss the potential risk of a nerve injury.


An injury to one of the nerves of the foot often leads to a neuritis (painful inflammation of a nerve). The initial nerve injury may be relatively minor, such as: a nerve that is stretched while retracting the soft-tissues during surgery; or a nerve that becomes trapped in scar tissue that forms in response to post-operative bleeding. This type of nerve irritation creates symptoms, such as numbness and/or a burning sensation along the course of the nerve. The localized nerve injury is often associated with a surgical incision and pressing on the area of the nerve injury may create a sharp pain or sense of discomfort along the course of the nerve, which is known as a "Tinel sign." Examples of operations that may lead to local nerve injuries include:

  • Ankle arthroscopy where the outside (lateral) incision (portal) is right near a branch of the superficial peroneal nerve.

  • Open reduction and internal fixation (ORIF) of an ankle fracture where the outside (lateral) incision may injure or irritate the superficial peroneal nerve.
  • Tarsal tunnel release where the tibial nerve is exposed and released but often heals with excessive scar formation, leading to increased pain.

Delayed Union / Non-Union

Many foot and ankle operations involve fusing joints (arthrodesis) or attempting to get fractures to heal. If a joint has not fused or a fracture has not adequately healed in the time that healing would be expected, then the area is said to be a delayed union. The time expected to achieve adequate healing can vary widely, from 6 weeks-10 weeks (or even longer), depending on the size of the joint, the blood supply to the area, and how immobilized the area is. Many delayed unions will go on to eventually heal. Some delayed unions can be encouraged to heal with the use of a bone stimulator, which passes current through the area to encourage bone healing. If no evidence of satisfactory healing has been demonstrated after a certain period of time (usually 6 months), then this is described as a "non-union."  Risk factors for a non-union include:

  • Smoking (Typically increases the risk of non-union by 3X)
  • Inadequate immobilization (either because the patient walked on the area too soon, or because the fixation was poor)
  • Diabetes
  • Poor blood supply to the area (One of the reasons smoking is a big risk factor)
  • Previous non-union in the area (i.e. revision surgery for non-union has a much higher rate of non-union)

The rate of non-union varies widely, depending on the patient's risk factors, the joints involved, and the fixation obtained by the surgeon. Typically non-union rates in otherwise healthy and compliant patients are on the order of 5-10% for many common foot fusions (ex. ankle fusionsubtalar fusion), but may be lower if there is lots of good healing bone (ex. Calcaneal Osteotomy) or higher in areas of the foot where the blood supply may be tenuous and the forces great (ex. talonavicular fusions).

Pulmonary Embolism (PE)

A pulmonary embolism occurs when a blood clot breaks off and goes to the lungs. This is a very serious condition and can be potentially fatal. Fortunately, this is a very uncommon complication, occurring in less than 1/3000 patients who undergo foot and ankle surgery. Pulmonary embolisms more commonly occur in patients undergoing hip and knee surgeries. Your surgeon may anti-coagulate your blood if you have a major risk factor for developing a PE.

Vascular Injury

Bleeding is not very common during surgery due to the use of a tourniquet. Vascular injuries that can occur following surgery include loss of blood supply to a distal extremity (like a toe). People with vascular diseases and diabetes are at higher risk of developing a vascular injury. Certain procedures on toes carry a higher risk for vascular injury.

Wound Healing Problems

Wound healing problems include scarring and wound breakdown that can lead to infection. This complication occurs in about 1/100 or less patients. People with diabetes, smokers, and those who have had previous surgery are at a higher risk of having a problem with wound healing.

Edited February 18, 2019

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