Ruptured pseudoanuerysm of the posterial tibial artery after percutaneous Achilles tenotomy

Abstract

Congenital talipes equinovarus (CTEV), or clubfoot, is the the most common encountered musculoskeletal defect encountered at birth. Most cases present as an isolated deformity, with up to half of them presenting with bilateral deformity. CTEV have also been reported to present as part of syndromic phenomena. Dr Igancio Ponseti proposed a serial casting programme to correct the foot’s cavus, forefoot adduction, varus and equinus. Up to 90% of infants will require a tendo-achilles (TA) tenotomy for the persisting equinus deformity. TA tenotomy is deemed a relatively safe procedure, with the most authors citing bleeding as the most common complication. The Achilles tendon finds itself surrounded by rich network of blood vessels and nerves. We present a case of a ruptured pseudoaneurysm from the posterior tibial artery after percutaneous TA tenotomy was performed. This is a very rare complication and to our knowledge, only one other posterior tibial artery pseudoaneurysm has been reported.

Background

Congenital talipes equinovarus occurs in about 1–2 newborns per 1000 births.¹ The exact aetiology is still not clear, but genetic and environmental factors are thought to play a key role. Chen et al² proposed that family history, parents who smoke, gestational diabetes, maternal obesity, amniocentesis and the use of SSRIs to be the most common associated factors. The Ponseti casting method has become the standard treatment form as it is deemed safe and effective.³ Between 85% and 90% of patients will require a tendo-achilles (TA) tenotomy to correct the persisting equinus deformity.³ Tenotomy procedures can be done as an open procedure (via a skin incision) in theatre, although some centres have good success rates with tenotomies done in outpatient clinics. After the tenotomy is performed, infants are required to wear a cast for another 3 weeks and thereafter bracing can commence. The bracing phase consists of an abduction foot orthosis (Dennis Browne bar and shoes) that is worn for 23 hours per day for 90 days. Thereafter, the brace is worn only at night time, until the child reaches 4 years of age. TA tenotomies are considered safe. Dobbs et al⁴ reported four cases of bleeding after tenotomy. Injuries to structures surrounding the Achilles tendon (figure 1) (including pseudoaneurysm) are rare.⁵

Figure 1.

Important anatomical structures surrounding the Achilles tendon (image drawn by Chané Rademan).

Case presentation

A 3-week-old boy presented to clubfoot clinic with bilateral idiopathic clubfeet. Pirani scores on the left and right feet were 5/6 (figure 2). The infant also had poorly developed heels. Serial Ponseti casting was started. The patient was eventually admitted for accelerated Ponseti castings, as the feet were very stiff and deemed resistant to casting. After this also have failed, the decision was made to perform bilateral TA tenotomies as conservative treatments have failed. Percutaneous TA tenotomies were performed on both feet in the operating theatre. There was minimal bleeding and posttenotomy casts were applied. A swelling was noted on the left foot’s surgical site at the 3 weeks follow-up (figure 3). Doppler ultrasonography showed a mass behind the medial malleolus. The ultrasound report included haematoma and abscess as differentials, but pseudoaneurysm could not be ruled out as the oedema around the wound made visualisation difficult. After consulting with other orthopaedic surgeons and a paediatric surgeon, the decision was made to manage the suspected pseudoaneurysm conservatively. Limited data on the management of this complication existed. A similar case presentation (but possibly a different vessel) was reported to have a good outcome with continuation of serial casting.⁶ Weekly casting and inspections were done. At the third follow-up visit, the pseudoaneurysm ruptured while the casts were removed. Direct pressure was placed over the bleeding vessel and the patient was rushed to theatre. An emergency exploration of the bleeding vessel was undertaken by the surgeon on call. The bleeding vessel was identified as the posterior tibial artery and was successfully ligated. The patient made an uneventful recovery and bracing was commenced. After about 6 months of bracing, the patient’s family moved and he was referred to another facility for follow-up and completion of his bracing. At the time of referral, the right foot achieved 38° of dorsiflexion (figure 4) and the left foot 36° of dorsiflexion (figure 5).

Figure 2.

Photograph of feet at presentation.

Figure 3.

Photograph of the left foot swelling.

Figure 4.

Photograph of the right foot at time of discharge.

Figure 5.

Photograph of the left foot at the time of discharge.

Treatment

Serial casting (as per Ponseti protocol). TA tenotomy required on both feet. Left foot developed a pseudoaneurysm which was managed by continuation of casting and close follow-up. At the third postoperative visit, the pseudoaneurysm ruptured while the cast was taken off in clinic. Emergency surgery was done with ligation of the affected blood vessel. Casting and eventual bracing.

Outcome and follow-up

Following surgery for ligation of the posterior tibial artery, the patient made a full recovery and bracing could continue. The family relocated to another town and the patient was referred to another centre. At the time of discharge, the patient was healthy and was making good progress.

Discussion

The Ponseti method for the management of idiopathic clubfoot has gained popularity in the last couple of years. It was first proposed by Dr Ignacio Ponseti some 40 years ago.⁷ Dobbs et al⁴ reported performing tenotomies on 200 of his 219 reported clubfoot cases and Burghardt et al⁶ reported 28 tenotomies out of the 34 cases. Tenotomies are deemed to be relatively safe, with bleeding being the most common complication. Dobbs et al reported four cases where serious bleeding after tenotomies was reported.⁴ Deformed or absent blood vessels to the foot have been reported in infants with clubfeet. It is therefore imperative that a detailed vascular examination of the foot is performed before any surgery is performed. The most common vascular anomaly is associated with the anterior tibial artery, with a reduction or complete absence occurring in up to 40%.⁸ If there is reduced or absent blood flow in the anterior tibial artery territory, ligation of the posterior tibial artery can cause necrosis of the foot.⁴ Mardjetko et al⁹ reported four cases (out of 2756) of vascular injury (pseudoaneurysms) in elective foot surgery in paediatric patients. Vascular injuries after TA tenotomies for patients with clubfeet usually involve the peroneal artery, which lies anteriorly and laterally to the Achilles tendon, with the sural nerve and lesser saphenous vein lying anterolateral to it.^10–12 These structures are the most commonly encountered when performing a TA tenotomy and a detailed understanding of the regional anatomy around the Achilles tendon is a must before performing the procedure (figure 1).⁵ Injury to any of the vascular structures might not be picked up shortly after surgery. Regular follow-up and close inspection of the foot is therefore imperative. The diagnostic modality most often used is ultrasound; angiography can be used in difficult-to-diagnose cases. Various treatment modalities exist for the management of an iatrogenic pseudoaneurysm. Burghardt et al⁶ described success with well-moulded serial casting. Other modalities include surgical repair (or ligation), ultrasound guided thrombin injection and ultrasound-guided compression or stenting.^{13 14} If left untreated, a pseudoaneurysm may be complicated by infection, compression of surrounding neurovascular structures and even haemorrhage.⁶

Our patient presented with an already ruptured pseudoaneurysm and life threatening bleeding. Immediate surgical ligation of the posterior tibial artery was deemed to be the best option at that stage. The patient made a full recovery and was able to continue with the management plan set out before his complication. Even though TA tenotomy is relatively safe, this case highlights the fact that no surgical procedure is without risk. The procedure was done by a well-trained, experienced surgeon. The choice was made to continue with serial casting and monitoring, as this was previously described to be successful in a case similar to ours.⁶ The survival and success of the patient’s ruptured pseudoaneurysm can largely be attributed that the rupture occurred in the outpatients department. Immediate resuscitation and surgical intervention was therefore available. The management of an unruptured pseudoaneurysm is still unclear and should be decided on a case-by-case basis. No two cases are the same and implying that all pseudoaneurysms should be managed in the same way would be naïve. A thorough evaluation of the vascular status of the foot should be done before the tenotomy if altered blood flow in the foot is suspected. Doppler ultrasonography is a useful, non-invasive tool that can help identify decreased baseline vascular supply. A mini-open procedure can be considered to reduce the risk of complications from a tenotomy in a foot with reduced blood flow.¹⁵

Pseudoaneurysm after TA tenotomy is extremely rare (but life threatening) and very few cases have been reported. Postoperative swellings should be thoroughly investigated and a pseudoaneurysm should be high on the list of differentials and must be ruled out. Most injuries to blood vessels are from the peroneal artery.

Learning points.

• Tenotomy is considered safe, but severe and life threatening complications can occur.

• Pseudoaneurysm is rare but life threatening complication and should be suspected (and ruled out) for all postoperative swellings.

• Always have a high index of suspicion for investigating suspected vascular injuries.

• A mini-open procedure should be considered to reduce complications in a foot with suspected reduced vascular flow.

Ethics statements

Patient consent for publication

Consent obtained from parent(s)/guardian(s).