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Posterior ankle impingement syndrome

Posterior Ankle Impingement Syndrome(PAIS)


Disease name/condition

Disease name: Posterior ankle impingement

Posterior Ankle Impingement Syndrome (PAIS)

Impingement, which means "trapping", is a disorder that causes pain and limited range of motion in the ankle joint due to pathological bones, soft tissues, or accessory bones.

Posterior Impingement Syndrome

called. A typical example is impingement of the triangle bone and retrotalar process, which is often seen in classic volleyball players and soccer players (instep kick), and significantly reduces performance.



If you have ankle pain or limited range of motion, we will examine the cause of the pain through examination and detailed images (CT/MRI). Even if the bone (triangle bone) or soft tissue is incised, the same​ symptoms.

​There is impingement of the flexor hallucis longus tendon (FHL), and pain is induced by bending the thumb and applying resistance.



3 Treatment method


First of all, we will basically do conservative treatment.

Surgery is indicated for cases that do not improve with conservative treatment such as oral anti-inflammatory analgesics, exercise therapy, and tape fixation.

surgical therapy

open surgery

​Arthroscopic surgery

Surgery involves excision of impingement bone, inflamed synovium, and soft tissue. Surgery is highly effective and can be expected to improve pain, limited range of motion, and improve performance. I have. Instability should be evaluated thoroughly after resection, and operable ligaments should be repaired and reconstructed at the same time.

Anesthesia is entrusted to the department of anesthesiology and performed under general anesthesia or spinal anesthesia.

In our hospital, we perform arthroscopy. With arthroscopy, there is less discomfort at the wound site and it is minimally invasive, allowing early return to sports.

If preoperative examination reveals instability due to ligament damage, ligament repair/reconstruction (see attachment) will be performed at the same time.

  • Insert the arthroscope first.

Inject 5 cc of physiological saline from the outside to the rear of the ankle joint. A 5mm incision is made medially and laterally along the Achilles tendon behind the ankle joint. Insert the camera and insert the necessary equipment (such as a shaver) from the other end. The hindfoot is filled with soft tissue, so the soft tissue and synovium are excised.

Identify the flexor digitorum longus tendon and expose the deltoid bone. Since the triangular bone is strongly attached to the retrotalar process by the fibrous tissue, it is peeled off. The triangular bone is basically removed as a single mass.

There are few cases where only the triangular bone is the cause, so we treat the retrotalar process, tendon sheath, synovitis, etc. If a free body (popular name: joint mouse) is recognized, it will be removed. If it is not the cause of the impingement but causes extra-articular or other tissue damage, we may choose not to treat it. After confirming that the tumor has been sufficiently resected with an arthroscope and X-rays, the surgery is completed.

Assess ankle instability after radiographic confirmation. If instability is recognized, there is a possibility of treating the ligaments, etc.

*Intraoperative images and collected tissues will be used for future research with the consent of the patient. At that time, we will properly manage the handling of personal information in accordance with the regulations of universities and hospitals.



Postoperative course:

After surgery, follow the flow in the table below. Limit plantar flexion and start range of motion training early, and load from the next day (first wrapping). Stitch removal takes around 7-10 days. Jogging will start after about a month, and rehabilitation will be carried out with the aim of returning to work in 6-8 weeks.

* Post-treatment may change depending on individual cases.

Risks of this surgery and its incidence

□ Infection (in severe cases, metal removal may be required): Surgical wounds can become infected (about 1%). In particular, people with diabetes, malignant tumors, and the elderly are at high risk of infection due to their weak immune system. The same is true for those taking immunosuppressants. It has been reported that surgery using metal has a higher risk of infection than surgery that does not use metal. When deep infection occurs after surgery using metal, multiple types of surgery, such as removal of metal fixation materials, scraping of infected lesions, continuous irrigation, and open wound therapy, may be unavoidable, requiring long-term hospitalization. become In addition, if the bacteria are multidrug-resistant bacteria such as MRSA, antibiotics are almost ineffective, so long-term hospitalization is required in this case as well. Sepsis can be fatal.

□ Joint contracture: The ankle joint is swollen with saline and operated. Joint contracture may occur due to invasive surgery and rest. Early rehabilitation is important.

□ Remaining pain: Since the affected area is artificially invasive, discomfort and pain may remain. Some people are prone to keloid-like scar formation at the incision site.

□ Nerve/Vascular Injury: Avoid nerves/vessels for surgical operations. However, nerves may run differently in each individual, and traction and adhesion due to surgical manipulation may cause symptoms such as sensory disturbance, numbness, bleeding, and motor paralysis that were not observed before surgery. Basically, it is temporary and improves, but such symptoms may remain permanently. In severe cases, reconstructive surgery may be required. This surgery may cause numbness in the superficial peroneal nerve area.

□ Deep vein thrombosis/pulmonary infarction/fat embolism: Stagnation of blood flow due to trauma, bed rest, etc. may cause blood clots in the lower extremities (approximately 10-20%). If blood clots (fat) fly into the lungs and become clogged, pulmonary infarction and respiratory failure can occur, and in severe cases, it can be fatal (0.3%). In addition, clots and fat flying into the blood vessels of the brain and heart can be fatal.

□ Implant damage/implant damage to surrounding tissue: There is a rare possibility that the instrument being investigated or the metal used to insert the anchor will break and remain in the joint or bone. Basically, it is removed, but in most cases it does not affect the human body, and if it is highly invasive, it may not be removed.

□ Compartment syndrome: Due to damage to the soft tissue during surgery, the internal pressure of the lower leg compartment increases, compressing blood vessels and nerves, and nerve paralysis and blood circulation disorders may occur. Emergency surgery may require a fasciotomy.

□ Complex regional pain syndrome (CRPS): An intractable chronic pain syndrome accompanied by symptoms such as chronic pain and edema, abnormal skin temperature, and abnormal sweating. In addition to surgery, bone fractures, sprains, and bruises can also be triggers, and their causes and mechanisms have not yet been fully elucidated.

□ Others: Unexpected accidents and complications may occur.


5 Responses in the event of accidental events

In the event of complications during and after surgery, best measures will be taken. (In addition, medical care at that time will be covered by regular insurance.)


6 Alternative treatments

Conservative treatment: Fixation therapy with braces, suspension of sports and rehabilitation aiming to return to sports.


7 Expected progress without surgery

If instability persists, it may progress to osteoarthritis of the ankle.

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