[Vascular injuries in joint replacement surgery]

Iatrogenic injuries to blood vessels in joint replacement surgery are rare events that occur as few per thousand. However, their sequelae are serious. The patient may either bleed to death, because vascular injury is not obvious and therefore difficult to diagnose, or lose the limb due to ischaemia. The highest risk of vascular injury is associated with repeat surgery and loosening of the acetabular component. We distinguish sharp and blunt force injuries. The former are caused by implants, sharp instruments, bone fragments or bone cement debris. The latter arise from stretching over a part of implanted material. Bleeding can be inapparent or apparent. Inapparent bleeding is difficult to diagnose and is recognized from the dynamics of blood losses. Haemodynamic instability or, in a worse case, even hypovolaemic shock may be the only signs of bleeding. Occlusion of an artery is manifested by limb ischaemia. The seriousness and progression of ischaemia depends on the rate of arterial occlusion, potential pathways for collateral circulation and the degree of atherosclerotic vascular disease. The patient with conduction anaesthesia does not feel pain and therefore the diagnosis must primarily be based on arterial pulsation in the limb and its skin colour. A pseudoaneurysm can develop due to a partially weakened vascular wall and its rupture is a life-threatening complication. Its presence is recognized as a pulsating mass in the groin. An arterio- venous fistula which arises from traumatic communication between the two vessels may lead to cardiac failure. The diagnosis is based on examination by sonography and digital subtraction angiography. The results of CT angiography and MR angiography are difficult to evaluate because of the presence of metal implants. In apparent bleeding it is sometimes difficult to locate the source. It is recommended to perform digital compression and gain access to the vessels from the extraperitoneal approach. When an expanding haematoma or ischaemia is present, the artery can be treated by surgical exploration or percutaneous transluminal angioplasty. A possibility of vascular injury should be taken into account particularly in revision arthroplasty. To check blood flow in the limb before surgery is advisable. If the procedure entails a significant risk of post-operative complications, a vascular surgeon should be available. In the case of acute intra-operative bleeding, the source should be localised as soon as possible, the site compressed and an expert assistance called in. When the source is not obvious, it should not be attempted to apply vascular clamps or clips at random; this may do even more damage to the vessel.