**2. General complications**

#### **2.1. Urinary tract infection**

Urinary tract infections represent an approximately 13% of all healthcare-associated infection [5] and in the context of post total hip replacement is seen to be the most common minor postoperative compilation [6]. The estimated rates of postoperative urinary tract infections are at 3.26 [7]. Risk factors for the development of a urinary tract infection include female sex, increased age, ASA 3 or higher and the use of a general anaesthetic [6]. Of these in a recent multicentre study by Alvarez et al., increased age followed by female sex was the strongest variable in developing a postoperative urinary tract infection. As with respiratory tract infections to be discussed in the next section, urinary tract infection in the postoperative setting following total hip replacements have been linked to more significant adverse effects such as peri-prosthetic infections, implant failure and revision procedures along with the immediate prolonged hospital stay [8].

Although half of patient who develop a deep vein thrombosis post total hip replacement have no identifiable risk factor there are numerous well recorded risk factors that alter Virchow's triad towards a state of thrombus formation [16]. These include associated fracture, malignancy, previous history of thromboembolism, immobility, obesity, pro-thrombotic conditions such as anti-phospholipid syndrome and the use of oral contraceptive pills. Furthermore an

Complications of Total Hip Replacement http://dx.doi.org/10.5772/intechopen.76574 125

The prophylaxis for deep vein thrombosis is aimed at returning the pro-thrombotic state into equilibrium by adjusting the parameters of Virchow's triad. This is done by treating the stasis of flow in the lower limbs both by mechanical thromboprophylaxis but also by the choice of anaesthetic used. A regional anaesthetic has been shown to reduce the risks of deep vein thrombosis over that of general anaesthetic by 50% alone due to the relative improvement in the flow of venous blood in the lower limbs [17]. Furthermore chemical thromboprophylaxis can be used to reverse the hypercoagulability. Various agents are used for chemical thromboprophylaxis but include low molecular weight heparin and more recently oral factor Xa inhibitors. Mechanical and chemical prophylaxis are utilised both intra and postoperatively

Deep vein thrombosis has a risk of propagating proximally through the right sided cardiac circulation into the pulmonary system. If the thrombus passes into the lungs they result in pulmonary embolisms. The results of these pulmonary embolisms can vary from being asymptomatic to caused catastrophic respiratory failure and can be fatal and pulmonary embolus being one of the leading causes of mortality post total hip replacements. The overall rates of postoperative total hip replacements are 3% in the absence of chemical prophylaxis [15], and 0.21% when chemical prophylaxis is used from a recent large review [18]. The prevention of pulmonary embolism lies primarily in the prevention of deep vein thrombosis discussed in the previous section. The treatment of established pulmonary embolisms are by the use of therapeutic agents to inhibit the pro-thrombotic cascade and profibrinolytic agents to dissolve

In the same way that a deep vein thrombus can pass into the pulmonary circulation, at the time of implant insertion the rise of intramedullary pressure from the prosthesis and cement can cause the embolization of medullary fat and marrow contents into the venous system [19, 20]. If the fat or marrow then passes into the pulmonary circulation in can pass in the pulmonary arteries in the same way as a venous thrombus causing much the same issues. These bodies of fat can also pass into the left sided circulation and cause cerebral embolisms and infarction causing neurological deficits [21]. By the same pattern the fat bodies can cause infarcts in the systemic circulation in tissues causing a classic upper body petechiae. As such the classic symptomatic triad of fat embolism is respiratory distress, neurological symptoms and upper body petechiae. To avoid such complications the intra-medullary canal is lavage

ASA grade of greater than 3 is an independent risk factor [16].

to reduce the overall risk of deep vein thrombosis.

*2.3.2. Pulmonary embolism*

away the embolus.

*2.3.3. Fat embolism*

#### **2.2. Postoperative pulmonary complications**

Postoperative pulmonary complications are common after major surgeries and are defined as a collective of respiratory failure, pneumonia, pleural effusion, atelectasis, pneumothorax and aspiration pneumonia [9]. Postoperative pulmonary complications are a common complication after total hip replacement with 45.9% patients having some form of postoperative pulmonary complications on postoperative CT screening [10]. The symptoms of any postoperative pulmonary complication can vary greatly with many atelectasis following general anaesthesia being asymptomatic but as like urinary tract infections can cause more serious complications along with increased length of stay. The rate of in-patient pneumonia following total hip replacement is estimated to be between 0.74 and 0.86% [7].

#### **2.3. Thromboembolic complications**

#### *2.3.1. Deep vein thrombosis*

Deep vein thrombosis is a common complication following total hip replacements due to the venous stasis and hypercoagulability experienced both during and subsequent to the procedure, adversely influencing Virchow's triad towards a state of thrombus formation [11]. The subsequent results of deep vein thrombosis can vary from asymptomatic, chronic venous insufficiency and proximal propagation. Without the use of any prophylaxis the overall radiological diagnosed rates of deep vein thrombosis has been as high as 70% in total hip replacement cases [12].

With the introduction of modern thromboprophylaxis the overall rates of deep vein thrombosis has reduced to approximately 44% and in those that are symptomatic as low as 1.3% [13, 14]. Thankfully with prophylactic treatment the rate of symptomatic proximal propagation to form a pulmonary embolus is lower still at less than 0.6% [15].

Although half of patient who develop a deep vein thrombosis post total hip replacement have no identifiable risk factor there are numerous well recorded risk factors that alter Virchow's triad towards a state of thrombus formation [16]. These include associated fracture, malignancy, previous history of thromboembolism, immobility, obesity, pro-thrombotic conditions such as anti-phospholipid syndrome and the use of oral contraceptive pills. Furthermore an ASA grade of greater than 3 is an independent risk factor [16].

The prophylaxis for deep vein thrombosis is aimed at returning the pro-thrombotic state into equilibrium by adjusting the parameters of Virchow's triad. This is done by treating the stasis of flow in the lower limbs both by mechanical thromboprophylaxis but also by the choice of anaesthetic used. A regional anaesthetic has been shown to reduce the risks of deep vein thrombosis over that of general anaesthetic by 50% alone due to the relative improvement in the flow of venous blood in the lower limbs [17]. Furthermore chemical thromboprophylaxis can be used to reverse the hypercoagulability. Various agents are used for chemical thromboprophylaxis but include low molecular weight heparin and more recently oral factor Xa inhibitors. Mechanical and chemical prophylaxis are utilised both intra and postoperatively to reduce the overall risk of deep vein thrombosis.

#### *2.3.2. Pulmonary embolism*

**2. General complications**

Urinary tract infections represent an approximately 13% of all healthcare-associated infection [5] and in the context of post total hip replacement is seen to be the most common minor postoperative compilation [6]. The estimated rates of postoperative urinary tract infections are at 3.26 [7]. Risk factors for the development of a urinary tract infection include female sex, increased age, ASA 3 or higher and the use of a general anaesthetic [6]. Of these in a recent multicentre study by Alvarez et al., increased age followed by female sex was the strongest variable in developing a postoperative urinary tract infection. As with respiratory tract infections to be discussed in the next section, urinary tract infection in the postoperative setting following total hip replacements have been linked to more significant adverse effects such as peri-prosthetic infections, implant failure and revision procedures along with the immediate

Postoperative pulmonary complications are common after major surgeries and are defined as a collective of respiratory failure, pneumonia, pleural effusion, atelectasis, pneumothorax and aspiration pneumonia [9]. Postoperative pulmonary complications are a common complication after total hip replacement with 45.9% patients having some form of postoperative pulmonary complications on postoperative CT screening [10]. The symptoms of any postoperative pulmonary complication can vary greatly with many atelectasis following general anaesthesia being asymptomatic but as like urinary tract infections can cause more serious complications along with increased length of stay. The rate of in-patient pneumonia following

Deep vein thrombosis is a common complication following total hip replacements due to the venous stasis and hypercoagulability experienced both during and subsequent to the procedure, adversely influencing Virchow's triad towards a state of thrombus formation [11]. The subsequent results of deep vein thrombosis can vary from asymptomatic, chronic venous insufficiency and proximal propagation. Without the use of any prophylaxis the overall radiological diagnosed rates of deep vein thrombosis has been as high as 70% in total hip replace-

With the introduction of modern thromboprophylaxis the overall rates of deep vein thrombosis has reduced to approximately 44% and in those that are symptomatic as low as 1.3% [13, 14]. Thankfully with prophylactic treatment the rate of symptomatic proximal propagation to form

**2.1. Urinary tract infection**

124 Total Hip Replacement - An Overview

prolonged hospital stay [8].

**2.2. Postoperative pulmonary complications**

**2.3. Thromboembolic complications**

*2.3.1. Deep vein thrombosis*

ment cases [12].

total hip replacement is estimated to be between 0.74 and 0.86% [7].

a pulmonary embolus is lower still at less than 0.6% [15].

Deep vein thrombosis has a risk of propagating proximally through the right sided cardiac circulation into the pulmonary system. If the thrombus passes into the lungs they result in pulmonary embolisms. The results of these pulmonary embolisms can vary from being asymptomatic to caused catastrophic respiratory failure and can be fatal and pulmonary embolus being one of the leading causes of mortality post total hip replacements. The overall rates of postoperative total hip replacements are 3% in the absence of chemical prophylaxis [15], and 0.21% when chemical prophylaxis is used from a recent large review [18]. The prevention of pulmonary embolism lies primarily in the prevention of deep vein thrombosis discussed in the previous section. The treatment of established pulmonary embolisms are by the use of therapeutic agents to inhibit the pro-thrombotic cascade and profibrinolytic agents to dissolve away the embolus.

#### *2.3.3. Fat embolism*

In the same way that a deep vein thrombus can pass into the pulmonary circulation, at the time of implant insertion the rise of intramedullary pressure from the prosthesis and cement can cause the embolization of medullary fat and marrow contents into the venous system [19, 20]. If the fat or marrow then passes into the pulmonary circulation in can pass in the pulmonary arteries in the same way as a venous thrombus causing much the same issues. These bodies of fat can also pass into the left sided circulation and cause cerebral embolisms and infarction causing neurological deficits [21]. By the same pattern the fat bodies can cause infarcts in the systemic circulation in tissues causing a classic upper body petechiae. As such the classic symptomatic triad of fat embolism is respiratory distress, neurological symptoms and upper body petechiae. To avoid such complications the intra-medullary canal is lavage cleaned prior to implant insertion to reduce the fat content. The treatment of fat embolism is supportive principally for the symptoms of respiratory compromise [22].

Radiological investigations can aid the diagnosis with signs of osteopaenia and osteolysis however there is no clear way to distinguish these from aseptic loosening on plain radiographs alone. Radionucelotide scanning can identify areas of increased bone turnover and inflammatory foci and are more sensitive and specific to deep infection. More specialist radiological investigations such as labelled white cell scans and immunoglobin scans and modern PET scanning techniques are more sensitive and specific still, at 85.5 and 92.6% respectively

Complications of Total Hip Replacement http://dx.doi.org/10.5772/intechopen.76574 127

Cytological and microbiological analysed sample can give both diagnostic information on the presence of infection but also the causative organism. Done radiologically under sterile conditions, a guided aspirate has been shown to have a sensitivity and specificity of 82 and 91% [36]. A surgically performed procedure allows the concurrent washout of the surgical site to furthermore reduce the organism load. Any such sample however should be taken with 2

The treatment of deep infection in total hip replacement is based on the principles of eradication of infection and restoration of function [37]. If deep infection occurs in the acute period, in the first 2 weeks, then component retention may be possible with thorough debridement and antibiotic treatment. However such this only results in clearance of infection in 50–74% of patients [38]. More often the presence of deep infection requires a full revision of the total hip replacement. This can be performed as either a single or two stage procedure. A single stage procedure is the removal of the prosthesis with thorough clearance of the infection with the implantation of a new prosthesis and subsequent antibiotics therapy. This differs to that of a two stage procedure whereby the first stage is the removal of the infected prosthesis, soft tissue debridement and the insertion of an antibiotic loaded spacer. After an interval of approximately 6 weeks of antibiotic therapy and the patient undergoes a second stage procedure with the insertion of a new prosthesis [39, 40]. The benefits of a single stage procedure are that of reduced operative morbidity however the results of successful treatment of the infection is consistently better with a two stage proce-

Haemorrhage can be classified into intraoperative haemorrhage and postoperative. Arthroplasty surgery is associated with significant levels of haemorrhage and a relatively high demand of blood transfusion [42, 43]. Haemorrhage that is deemed to be clinically significant is difficult to determine and varies between clinician, centres and trails. One large multi-centered study defines important haemorrhage to be as "*bleeding that is recorded by the surgeon as being outside the range of 'typical expected levels' of bleeding following THA/TKA, or bleeding that is cited as the cause of prolonged hospital stay"* [44]. Rates of intraoperative haemorrhage vary from 2 to 3.6 unit [44–47]. Risk factors for increased intraoperative haemorrhage rates include increased operative time, with one study demonstrating a 1 min increase in operative time resulting in a 1.552 ml increase in intraoperative bleeding in total hip replacements [48]. Low

and high BMI has been both associated with increased risk of haemorrhage [49, 50].

for PET scans, but the availability remains challenging [34, 35].

weeks of antibiotic cleared time to avoid any false negative findings.

dure at 87–94% [41] (**Figure 1**).

**3.2. Haemorrhage**
