Intraoperative periprosthetic femoral fractures (IPFs) occur at a higher rate in revision THAs compared to the primary setting. The reported incidence of IPF during primary THA is 0.23% for cemented stems but this rate increases up to 3% with uncemented THA (results from the Mayo Clinic, 2016) [1]. The rate during revision THA has been reported to be 6% during cemented revision THAs and 19% during uncemented revision THAs [2].

The key to preventing IPF is thorough preoperative surgical planning, assessing risk factors, and anticipating potential difficulty [4]. This can be achieved through taking a detailed history, an adequate clinical examination, and obtaining the necessary investigations. Preoperative radiographs should include an anteroposterior (AP) pelvis and a lateral view of the operative hip. Occasionally, additional imaging such as Judet views and/or a CT scan may be required to assess bone loss or deformity [7]. It is also essential to template the sizes of the components [7].

During primary THAs, the surgeon must ensure an adequate and a safe surgical exposure, including appropriate soft tissue releases. In the revision setting, the surgeon should be prepared for multiple options. The aim is to minimize the amount of bone loss while removing the components. If the femoral component is well fixed, then an extended trochanteric osteotomy (ETO) should be considered [7]. Some surgeon may elect to place a prophylactic cerclage cable or wire at the distal extent of an ETO to prevent propagation of a potential future fracture [7].

During canal preparation, attention should be paid to the alignment of the bone and the direction of inserting the reamers, broaches, and final femoral component. Eccentric reaming should be avoided and areas of bone loss should be protected. Intraoperative imaging may be useful to ensure central placement of the instruments in the intra-medullary canal [7].

The key to managing intraoperative periprosthetic femur fractures is early recognition. The use of suction, normal saline washes, and drying enable the surgeon to have a clear view of the bone. The surgeon needs to pay attention to the alignment of the femur and the direction of instruments (such as broaches or reamers) during the preparation or insertion of the stem. A sudden change in resistance is highly suggestive of a femoral fracture. In addition, using an implant with a size that is incosisting with preoperative templating should raise the suspicion of an intraoperative periprosthetic femur fracture. Finally, if the real implant advances beyond where the broach or trial seated, suspicion for an intraoperative fracture should be high and an X-ray obtained.

When a suspicion of IPF is raised during surgery, intraoperative radiographs should be obtained to confirm the diagnosis [7]. However, the absence of clear fracture on the intraoperative images may not be enough to exclude it, especially in cases of nondisplaced fractures, or if the patient is obese or if the intraoperative images obtained or otherwise of poor quality. Therefore, it is always important to correlate the clinical suspicion with radiographic findings. One may consider postoperative images in form radiographs and/or CT scan for further evaluation (Fig. 3.2).

Intraoperative periprosthetic femoral fractures can be classified according to the Vancouver classification. It is based on three elements: location, pattern, and stability of the fracture. There are three main types (A, B, and C). If the fracture involves the proximal metaphysis without extension into the diaphysis of the femur then it is type A. If it involves the diaphyseal bone around the tip of the femoral stem then it is type B. Type C fractures include those distal to the stem tip extending into the distal metaphysis [7]. Each category (A, B, and C) can then be subdivided into (3) subcategories including (1) cortical perforations, (2) nondisplaced linear cracks, and (3) displaced unstable fractures.

Most recently, this system was modified to the Unified Classification System (UCS) described by Duncan and Haddad in 2014 (Table 3.1) [8, 9]. It has six main types (A, B, C, D, E, and F). Type B can further be subclassified into three grades similar to the Vancouver type B fractures: 1) the implant is well fixed; 2) a fracture with a loose implant and good bone stock and 3) a fracture with a loose implant and poor bone stock) [8]. This system has the mnemonic described in the table, which helps understand and recall the classification Table 3.1 [8, 9].

By applying the UCS into the femur , the six types are: