Femoral pseudoaneurysm as a complication of slipped capital femoral epiphysis treatment.

Slipped capital femoral epiphysis is a very frequently seen condition in orthopedics centers worldwide. Even in successfully treated cases, complications related either with the pathology per se or with the chosen synthesis method are not rare. This report presents a case of bilateral slipped capital femoral epiphysis treated with pinning, in which one of the limbs developed a very rare condition: the formation of a femoral pseudoaneurysm that ruptured.

Introduction

Complications of treatment for proximal epiphysiolysis of the femoral head are frequent.

These include osteonecrosis (directly associated with the degree of stability of the lesion and with the surgical procedure), chondrolysis (a multifactorial and not fully understood condition, which can occur whether or not the disease is treated), femoroacetabular impact, and fixation failure with progression of the epiphyseal displacement.1, 2

The authors report a very rare complication that required a rapid and effective approach – the formation of a pseudoaneurysm associated with epiphyseal perforation by the screw, with injury and partial traumatic rupture of the femoral artery forming an extensive pulsatile hematoma in the thigh.

Case report

A 14-year-old male patient admitted to this hospital's emergency room reported pain, inability to ambulate, and increased volume in the upper right thigh (Fig. 1).

Fig. 1

(A) Initial clinical image of the patient showing volume increase in the upper thigh; (B) radiographic image of the pelvis on admission to hospital.

Symptoms began two weeks prior, with no history of trauma.

A progressive worsening of the condition was observed during that period. The patient's medical history indicated that he had undergone surgical treatment for proximal femoral epiphysiolysis on the left side three years before. On the right side, the same procedure had been performed four months previously: single screw pinning.

On physical examination, an extensive volume increase in the proximal region of the right thigh was observed. It was warm on palpation, and at first it was thought to be an abscess. Upon closer examination, it was observed that the mass was pulsatile, and there was a tremor on palpation and bruit on auscultation.

A puncture was made with a 7-gauge needle, and a strong stream of arterial blood was observed (Fig. 2).

Fig. 2

Thigh puncture, with a large quantity of blood freed under pressure.

After tamponading the bleeding, the vascular surgery team of the hospital was immediately called. The patient was admitted to hospital and prepared for surgical exploration of the hematoma by the orthopedic and vascular teams. In the intraoperative period, the head of the partially extruded screw of the epiphysis could be observed in the middle of the hematoma, together with lesion and formation of a femoral pseudoaneurysm. The screw was removed and the vascular lesion was repaired, with satisfactory results and without complications (Fig. 3). The patient returned to the outpatient clinic several times; after six weeks, he was capable of normal and painless gait, and presented normal peripheral pulses (Fig. 4, Fig. 5).

Fig. 3

Intraoperative image showing the tip of the screw that perforated the articular cartilage and injured the femoral artery, and also shows the formation of pseudoaneurysm.

Fig. 4

(A) Clinical aspect of the patient after six weeks, showing normal abduction; (B) hip flexion with a positive Drehmann's sign.

Fig. 5

Radiographic image of the pelvis six weeks after arterial repair and screw removal.

Discussion

The primary goals of the treatment of proximal femoral epiphysiolysis are to eliminate pain, maintain the anatomical relationship of the femoral neck and head, prevent future slip progression, and promote epiphysiodesis.1, 2

The secondary objectives are to avoid the complications inherent to the pathology and to reduce the risks of early degenerative alterations.

The gold standard of treatment is in situ fixation with a single screw. Biomechanical studies have demonstrated that the use of two screws leads to a more stable fixation; However, most orthopedic surgeons prefer to use of a single screw to avoid the risk of head perforation and subsequent chondrolysis.3, 4

Femoral neck osteotomy (Dunn) is able to perfectly restore hip anatomy, but the risk of necrosis can be over 20%.5, 6

Other controversies in treatment regard contralateral fixation and the period of time until weight-bearing is allowed.1, 3

The most common complications are chondrolysis, osteonecrosis, femoroacetabular impingement, and secondary arthrosis.

The present report demonstrated a very rare complication: the formation of pseudoaneurysm of the femoral artery by a screw used in situ fixation.

Conflicts of interest

The authors declare no conflicts of interest.