Vascular injuries are a rare but devastating complication after total hip arthroplasty (THA) [3, 4]. A recent meta-analysis by Alshameeri et al. [5] reports a total of 61 articles describing 138 vascular injuries in 124 patients in the last 22 years. However, to avoid a potentially life- or limb-threatening complication, arthroplasty surgeons should be intricately familiar with the anatomy, epidemiology and risk factors, causes of injury, and potential treatment options [3].

The incidence of vascular injuries during primary THA is considerably low. Abularrage et al. [6] found an incidence of 0.04% in a series of more than 13,000 primary THA [5]. Other authors have reported an incidence of 0.09–0.3% [7–9]. The orthopedic surgeon might encounter about one vessel injury every 14 years of practice [5]. Risk factors can be divided into patient, procedure, and implant-specific.

Patient-specific factors include a clinically relevant vascular disease, previous bypass operations, or revascularization procedures [7, 10–12]. A severely calcified atherosclerotic femoral artery poses a risk of spontaneous occlusion during the manipulation of the leg during total hip arthroplasty [7]. Vascular injuries are more common in female individuals [5]. Due to their anatomical proximity of the aorta to the hip joint, procedures of the left hip are at a higher risk for vascular injuries [10–12]. Patients who have undergone an aorto-bifemoral bypass are at high risk for vascular injury [13, 14]. If such a bypass is present, Cameron et al. [13] recommend performing a trochanteric osteotomy to avoid end-range positioning of the lower extremity. In concerning cases, patients should be evaluated by a vascular surgeon preoperatively.

Procedure-specific vascular injuries can occur either through indirect or direct trauma [15]. The most prevalent forms of injury are penetration or laceration [5]. Indirect trauma can be caused by stretching or compression during exposure, as well as dislocation and reduction of the joint. Cement extrusion and excessive use of electrocautery have been associated with thermal injuries of the vascular walls [16].

Direct trauma secondary to a retractor, scalpel, drill, or acetabular reamer can also occur [17]. Darmanis et al. [17] reported an increased risk of vascular injuries with the use of threaded acetabular components. In addition, cement, cables or wires, and aberrant placement of screws can harm vessels [18]. A quadrant system drawn in a lateral view on the acetabulum (Fig. 2.1) helps the surgeon to identify areas at risk for vessel injury during the drilling of the screw canal and screw insertion [1]. The safest zone is the posterosuperior quadrant (Fig. 2.1, zone B). In this quadrant, screws with a typical length of 35 mm may be used. Next, the posteroinferior quadrant (Fig. 2.1, zone D) allows screws typically no more than 25 mm. The anterosuperior and inferior quadrants are at high risk for screw placement . If necessary, only monocortical screws should be used.

The vascular structures at risk for injuries during primary THA include the common iliac, external iliac, superior and inferior gluteal, profunda femoris, femoral and obturator vessels (Figs. 2.1, 2.2 and 2.3) [12, 19]. Of these, the external iliac and common femoral arteries are involved most often [3]. The external iliac vessels follow the medial border of the psoas muscle. Harm to this vascular complex can occur during every step of the procedure if a retractor is placed too far medially over the anterior column of the acetabulum (Fig. 2.2). The psoas muscle is the only anatomical structure that separates the vascular complex from the capsule of the hip joint. That is why a retractor in this area should be placed with care and as laterally as possible to the surgical site. As the belly of the psoas muscle is more present proximally, the retractor should also be placed as proximally as possible. In addition, the iliac vessel can be injured when perforating the medial acetabular wall [11, 20]. In the case of a dysplastic acetabulum,some authors advocate placing the acetabular component as medial as possible to obtain sufficient bone coverage [21]. However, this puts the iliac vessels at risk for injury. If the preoperative planning results in a medial position of the acetabular component in order to get a good bone coverage and a perforation of the medial could be possible, the authors recommend performing a preoperative angiogram to show the anatomical relation between the bone and the vessels.

After it has crossed the ilioinguinal ligament, the external iliac vessel gives off the common femoral artery that runs anterior and medial to the hip joint (Fig. 2.3). Damage of these structures through retractors, the excessive removal of anterior osteophytes as well as secondary to forced dislocation or reduction has been described [11, 16]. Some approaches like the anterolateral and direct anterior approach have a higher risk of femoral artery injury [1]. The lateral and medial branch of the circumflex femoral artery derive from the profunda branch of the femoral artery and are at high risk for injury when retractors are placed too far medially over the anteroinferior quadrant , as well as during resection of the femoral head (Fig. 2.3).

The superior gluteal vessel, a branch of the internal iliac artery, can be harmed while placing a retractor too far posteriorly or when placing screws into the sciatic notch (Fig. 2.1). Wide acetabular and iliac exposure as is occasionally required in a complex primary THA (e.g. oncologic or post-traumatic) may also place this vessel at risk. The inferior gluteal vessel is also a branch from the internal iliac artery and is most often injured when placing screws into the posteroinferior quadrant.

The most common presenting feature is bleeding and a sudden loss of blood pressure [5]. If an injury to a major blood vessel is suspected and cannot be visualized (e.g., loss of blood pressure after screw placement), an intra-abdominal and/or retroperitoneal ultrasound or angiogram should be completed immediately. About 50% of vascular injuries are identified by occult or frank hemorrhage, including shock during surgery or within the first 24 h thereafter [5]. However, the other 50% do not manifest until 4 days after the index arthroplasty [8], mostly in patients with an epidural anesthetic. According to Calligaro et al. [8] epidural anesthesia can mask ischemic rest pain. A vessel injury can also present as visibly uncontrolled bleeding, thrombosis, compartment syndrome, or false aneurysm formation. False aneurysm formation is often identified at a late stage as the symptoms can vary and are unspecific. Shoenfeld et al. [11] report an average time to the diagnosis of a false aneurysm of 29 month after index surgery. They are not usually diagnosed unless the patient complains of unusual swelling and paresthesia due to compression of neurovascular structures [8]. If suspected, the dressing should be immediately removed; an angiogram or CT angiogram should be completed, along with urgent vascular consultation .