• Chapter: Orthopedic problems associated with vascular malformations

    Article: 5 of 9

    Update: Feb 24, 2021

  • Author(s): Kertai, Michael Amir

Two main causes of contractures in patients with vascular malformation can be distinguished:

  • Contractures due to prolonged immobilization or protective posture.
  • Contractures due to remodeling of the muscle by the malformation.

The correct differentiation of the cause is essential in order to choose the right therapy and to estimate the success of the therapy.

Contractures as a result of prolonged immobilization

As vascular malformations can always lead to chronic pain, patients often adopt a protective posture.The most frequently observed situation is complete relieving of a foot when it hurts because of the malformation when the foot touches the ground. The patient then assumes a hip and knee flexion for relief and thus lifts the foot off the ground while walking on forearm crutches. After just a few days, the hip and knee flexor muscles begin to shorten. The longer the restraint continues, the more pronounced the contracture becomes.

Another form of pain-related contracture occurs when the pressure of the surrounding musculature on the vascular malformation varies in certain flexion or extension positions and the patient chronically assumes the corresponding least painful position.

The following case study presents such a case and its treatment:

12-year-old patient with PTEN hamartoma of soft tissue in the area of the thigh directly above the left patella. As a result of pain caused by mechanical pressure during knee extension, a flexion posture was always adopted. Additionally there was leg length discrepancy with an excess length of approx. 3 cm of the left leg. The detailed picture shows the maximum possible active extension of the left knee. The X-ray shows additional dysplasia of the tibia. The vascular tumor (PTEN hamartoma) is located in the area of the distal thigh. Because the PTEN hamartoma is located mainly medial to the distal femur (T2-weighted MRI), a conversion osteotomy of the femur was planned via a lateral approach. The goal was to correct the knee flexion contracture with a single operation. Treatment of the vascular tumor was not the goal of therapy. As the patient had an excess length of more than 3 cm on the affected side, it was decided to perform the operation as a “closed-wedge” osteotomy and to correct the leg length discrepancy as well. Lateral X-ray image after the operation. The patient can now fully extend the left knee. Plaster or other immobilization is no longer necessary thanks to the use of a stable-angle implant. Thus, the patient can use his compression garments again and the duration of anticoagulation can be shortened.

Note: 1. The two visible threads are the radiographic strips of the dressing on the surgical wound.
Note: 2. The clear caliber jump above and below the osteotomy results from the removal of the 3 cm measuring wedge to correct for the leg length.

The therapeutic options must be assessed on a highly individual basis. The pure technical feasibility of a surgical treatment should not be the basis for a decision.

Especially in the case of pain-related contractures due to a painful vascular malformation on the sole of the foot, there is no point in treating the contracture surgically as long as the patient does not put any weight on the foot afterwards because of the pain and falls back into the same protective posture. In this case, an interdisciplinary approach in treating the vascular malformation is all the more important.

If there is no improvement in function even after contracture treatment, amputation must be considered as a final option.

Contractures due to muscle remodeling

Particularly in fibro-adipose vascular anomaly (FAVA), contractures are to be expected owing to the regular constrictive connective tissue remodeling with shortening of the musculature. Most frequently, this relates to the calf muscles and a resulting pes equinus.

In order to identify treatment options, it is necessary to understand how contracture occurs in fibro-adipose vascular anomaly:

There is a loss of extensible muscle due to the remodeling of the existing musculature partly into connective tissue (fibrous connective tissue and fat) structures, partly interspersed with dysplastic venous vessels.

As the underlying bone grows, the surrounding altered muscle can no longer adapt to the new length ratios. This then leads to increasing contracture.

However, this also means that therapy at the growth age always carries a high risk of recurrence. Nevertheless, treatment should not be carried out too late because the therapy of a long-standing acute foot contracture is more complex and rehabilitation of the patient is more difficult.

Therapy of contractures

The simplest therapy is Achilles tendon lengthening. It is a good option in patients who have little pain from the malformation and who have only a pes equinus.

Achilles tendon lengthening should be Z-shaped and performed openly in malformation patients. Percutaneous procedures potentially carry an increased risk of bleeding because of the sometimes massive phlebectasia.

If tolerated by patients, treatment with a night-time positioning orthosis should follow in the growing age in order to reduce the risk of recurrence or to delay the time of recurrence.

In patients with recurrent and severe pain due to fibro-adipose vascular anomaly (FAVA), Achilles tendon lengthening is an unsatisfactory option because, although this may temporarily correct the pes equinus, patients still do not use the involved leg on account of pain and because recurrence of the pes equinus is common as a result of intramuscular disease recurrence or progression.

In these cases, removal of the FAVA including the affected muscle is recommended. This can be a very complex procedure if nerves and normal vessels are encased by the malformation in the knee area. However, to date this seems to be the only therapeutic approach to treat both the contracture and the other symptoms caused by FAVA.

It should be noted, especially in patients with prolonged pain prior to surgery, that a long rehabilitation period should be expected, and pain management should be part of the treatment plan.

Likewise, one or more prior sclerotherapies of the venous malformation part of FAVA preoperatively is the rule. It is obligatory to close veins communicating with the deep conducting venous system beforehand (interventional or open surgery) in order to prevent the risk of thromboembolism.