Abstract
Periprosthetic fractures in total hip arthroplasty lead to considerable morbidity in terms of loss of component fixation, loss of bone and subsequent functional deficits. We face an epidemic of periprosthetic fractures as the number of cementless implants inserted continues to rise and as the number of revisions continues to increase. The management of periprosthetic fractures requires careful preoperative imaging, planning and templating, the availability of the necessary expertise and equipment, and knowledge of the potential pitfalls so that these can be avoided both intra-operatively and in follow-up. There is a danger that these cases fall between the expertise of the trauma surgeon and that of the revision arthroplasty surgeon.
The past decade has afforded us clear treatment algorithms based on fracture location, component fixation and the available bone stock. We still nevertheless face the enduring challenge of an elderly population with a high level of comorbidity who struggle to rehabilitate after such injuries. Perioperative optimisation is critical as we have seen prolonged hospital stays, high rates of systemic complications and a significant short term mortality in this cohort.
We have also been presented with new difficult fracture patterns around anatomic cementless stems and in relation to tapered cemented and cementless stems. In many cases, fixation techniques are biomechanically and biologically doomed to fail and intramedullary stability, achieved through complex revision is required.
The treatment of unstable peri-prosthetic femur fractures can be technically challenging due to the weak non-supportive bone stock. We have seen an increase in the frequency of Type B3 fractures that require complex reconstruction with modular tapers, interlocking implants and proximal femoral replacements. Our reconstructive practice has evolved; the aims of femoral reconstruction include rotational and axial stability of the stem, near normal hip biomechanics and preserving as much femoral bone as possible. The advent of modular prostheses that gain distal fixation but have proximal options has extended the scope of this type of fixation. We now favor modular tapered stems that afford us the opportunity to reconstruct such femora whilst attempting to preserve the proximal bone. In effect, distal cone or taper fixation provides the initial stability required for the procedure to be successful but the proximal modular implant subsequently load shares to decrease stress shielding, distribute stress more evenly through the femur and minimise the risk of stem fracture. Such systems provide the intraoperative versatility that these cases require. The use of interlocking stems with coated ingrowth surfaces offers a relatively appealing solution for some complex fractures and avoids the complications that would be associated with unstable fixation or resection of the proximal femur.
Periprosthetic acetabular fractures are also increasingly recognised. This is in part due to the popularity of press fit components, which increase fracture risk both at the time of insertion and later due to medial wall stress shielding and pelvic osteolysis, and partly due to the increasing frequency of severe defects encountered at the time of revision surgery. These can present a very difficult reconstructive challenge and may require porous metal, cup-cage or custom reconstruction.
Periprosthetic fractures continue to cause problems worldwide. The sequelae of periprosthetic fractures include the financial cost of fixation or revision surgery, the associated morbidity and mortality in an elderly frail population, the difficulty with mobilisation if the patient cannot fully weight bear and a poor functional outcome in a proportion of cases. The battle over which patients or fractures require fixation and which require revision surgery continues.
