Total Hip Arthroplasty: Complications and Results

Fig. 6.1

(a) Radiograph of a total hip arthroplasty in a 93-year-old female patient showing cup loosening; (b) postoperative radiograph after revision hip surgery with a bone impaction grafting technique and a cemented dual-mobility cup

The classic reasons for revision have been aseptic loosening and wear-related complications, but this must be interpreted depending on whether it is a first- or multiple-revision situation. To date, dislocations, infection, and fracture are increasing among multiple-revision patients and in older patients (Fig. 6.2). Finally, removal of the total implant or a component depends on the cause of revision: it is frequent to remove the entire implant in cases with infection, sometimes in cases with wear or loosening, the stem when there is a femoral fracture with associated osteosynthesis and the cup if there is a recurrent dislocation. Cemented or uncemented techniques require complex analysis since combined techniques with newer implants and the use of bone allograft are becoming more frequent.

../images/479782_1_En_6_Chapter/479782_1_En_6_Fig2_HTML.png — Fig. 6.2

Radiograph showing a dislocation after revision surgery with hip abductor deficiency

Other national registries report complementary data. The National Joint Registry (NJR), from England and Wales, also shows that revision procedures are rising during the last years. It also reports aseptic loosening, lysis, and wear also as the most frequent reason for revision [9]. The Australian Register (AOANJRR) reports similar data for first-revision cases; however, it also shows that dislocation was the most frequent cause for revision during the first 4 years after primary THA after which time is aseptic loosening and lysis became the most frequent cause [10]. All registries also report the importance of introducing new implants, like large friction THA with hard-on-hard implants and their influence on results. Interestingly, the NJR and AOANJRR analyses include diagnoses such as adverse reactions and emphasize the importance of these problems.

6.3 Epidemiological Studies

In epidemiological studies it is important to comment that revision and primary THA rates oscillate across different geographic areas. Multiple causes have been investigated in order to explain these findings. The number of surgeons, providers, population access, and other socioeconomic reasons can influence these data. In Spain, regional variability was higher than expected [11]. Despite a universal health coverage system, equity may be challenged in the administration of hip arthroplasty. When hip replacement rates were adjusted for sex and age, the regional aging index, the density of orthopedic surgeons, and the regional health budget could only partially explain risk ratio changes. An interesting finding was the influence that the regional density of orthopedic surgeons had on the adjusted rates of primary and revision THA. Data have shown that patients in regions with more orthopedic surgeons are more prone to receive a primary THA; however, revision THA did not follow this tendency. Paradoxically, a significantly lower risk ratio for revision rates was found in regions with more orthopedic surgeons. This could be an expression of insufficient resources or qualification to perform revision hip surgery in regions with a higher density of general orthopedic surgeons, with subsequent unmet needs for the population. In fact, this finding could even reflect that the higher rate of revision hip procedures in areas with fewer surgeons could be associated with higher failure rates related to insufficient caseloads.

6.4 Complications and Outcome in Revision Total Hip Arthroplasty: Big Data

As previously described, the most frequent indication leading to a first-revision THA procedure in most is mechanical complications such as loosening and wear; however, in further reoperations, there are more complications related to more challenging surgeries such as infection, venous thromboembolic disease (VTE), or dislocation. First, it must be noted that these patients may be older and can have more comorbidities than those undergoing primary THA. A study of a US Medicare population observed that advanced age, rather than orthopedic complications, was a clear risk factor for VTE and mortality [12]. To date, comorbidities were also related to all complication types, but dislocation and infection rates are of particular importance. The NJR in England and Wales reported that dislocation and infection gained importance when compared to mechanical complications, wear, pain, or lysis reason for re-revision THA. In terms of 90-day mortality, this was also lower after primary THA than after revision. SHAR also confirmed these data in terms of more dislocation, infection, and complex patients in multiple-revision procedures. Thus, some complications such as periprosthetic fractures have higher dislocation rates, and this leads to changing indications meaning being prepared to change both the cup and stem rather than only the stem.

In terms of long-term survival after revision or re-revision surgeries, the last Annual Report from the SHAR confirmed that this was lower in both first- and multiple-revision THAs than for primary THA as expected. They have also observed that the risk of a revision was lower in female patients than in males. The 2017 NJR reports that the cumulative percentage probability of revision is increased three times overall at 13 years when comparing primary and revision THA rates. Similar to other registries, the reasons for re-revision due to infection and dislocation were higher in the latter. Last, mortality was lower after primary surgeries, and they did not find differences in between sexes. Registry data have also revealed complications in revision THA.

6.5 Dislocation After Revision Total Hip Arthroplasty

This complex and multifactorial problem is more challenging in revision than in primary THA. Previous surgery affects not only the long bone but also soft tissue around the hip. Abductor biomechanics are probably one of the most important factors [13]. Despite recent interest in implants with large femoral heads, modular stems, or dual-mobility cups leading orthopedic surgeons to introduce newer techniques, reconstruction of the center of the hip with a correct lever arm distance, height of the greater trochanter, and component position must be the main objective of the surgery to obtain good results. To date, preoperative planning to evaluate bone defects, including greater trochanter status, is critical. In a previous history of at least one dislocation, acetabular bone defect and abductor deficiency are the most important factors for dislocation [7] (Fig. 6.2).

After dislocation, careful assessment is mandatory. Re-revision rates are a big problem not only in number but in clinical morbidity and dissatisfaction. Re-dislocation and re-revision rates at 15 years can be higher than 30% and 40% when revision THA is done due to instability [14]. Repeated dislocation after two or more surgeries, small femoral heads, and liner exchange with cup retention has a higher risk. Some alternative options like constrained liner use have not improved re-revision rates. On the other hand, dual-mobility cups are gaining popularity given their better results when combined with proper assessment of the components, bone defect, and abductor deficiency issues [15].

6.6 Periprosthetic Fractures After Revision Total Hip Arthroplasty

This is a well-known as a challenging complication. During femoral revision surgery, the possible bone defect, as in the acetabulum, determines surgery [16]. Although femoral preoperative assessment can help in surgical planning, removal of the previous implant may change the strategy. Heterotopic calcifications, abductor deficiency with scar tissue and muscular atrophy, greater trochanter weakness, and cement or porous-coated implants are frequent local conditions that affect the final intraoperative bone defect. An intra- and postoperative periprosthetic femoral fracture can occur regardless of the choice of implant type [17]. In order to facilitate femoral component extraction, an extended femoral osteotomy has been reported [18]. This technique can be effectively performed and combined with different reconstruction techniques like impaction bone grafting [19] (Fig. 6.3).

../images/479782_1_En_6_Chapter/479782_1_En_6_Fig3_HTML.png — Fig. 6.3

Radiograph showing a femoral impaction bone grafting technique with a cemented stem combined with an extended trochanteric osteotomy

The first problem after a periprosthetic fracture has occurred is to diagnose and classify [20]. During revision there are many factors that influence the appearance of a fracture, as mentioned above. Any audible crack or a changing resistance during impaction must be checked with imaging in order to detect. The explanation for intraoperative fracture management cerclage wires and a complete set with screws and plates must be ready for use. When a periprosthetic fracture is found after a given time after revision surgery, proper classification is critical [21] (Fig. 6.4). A distal femoral fracture is relatively easy to identify; however, the treating surgeon ought to suspect a loosened femoral component when a fracture occurs around the stem. Finally, refracture after a periprosthetic fracture is a very complex situation with a relatively high rate for infection, malunion, and residual limping and is usually related to a poor outcome [22] (Fig. 6.5).