Abstract
Intraoperative fractures during primary total hip arthroplasty (THA) can occur on either the acetabular or the femoral side. A range of risk factors including smaller incision surgery, uncemented components, prior surgery, female sex, osteoporosis, and inflammatory arthritis have been identified. Acetabular fractures are rare but when they do occur often are underrecognised. It is not uncommon for intraoperative acetabular fractures to be discovered only postoperatively. Intraoperative acetabular fractures are associated with cementless implants and a number of identified anatomic risk factors. Factors related to surgical technique, including excessive under-reaming, excessive medialization with aggressive reaming, and implant designs such as an elliptical cup design are associated with higher risk. Treatment of acetabular fractures is dependent on whether they are diagnosed intraoperatively or postoperatively. When discovered intraoperatively, supplemental fixation should be added in the form of additional screw fixation, placing a pelvic plate, or using an acetabular reconstruction cage and morselised allografts. Acetabular reamings, obtained during preparation of the acetabulum, can be used for local bone graft. The goal should be stability of both the fracture and acetabular cup. Postoperatively, weight bearing and mobilization protocols may require modification, with many surgeons choosing a period of toe-touch weight-bearing in such cases. Acetabular fractures found postoperatively require the surgeon to make a judgement on the relative stability of the implant and the fracture to determine if immediate revision surgery or protected weight-bearing alone is appropriate.
On the femoral side intraoperative fractures can occur around the greater trochanter, the calcar, or in the diaphysis. Fractures of the greater trochanter are problematic because of their tendency to displace due to the attachment of the abductors and the strong force they apply. Tension band wiring techniques will work for many greater trochanteric fractures while a trochanteric plate may be occasionally called for. With either form of fixation strong consideration should be given to 6–8 weeks of protected weight bearing postoperatively. Short longitudinal cracks in the medial calcar region are not rare with uncemented implants. Calcar fractures that do not extend below the lesser trochanter can often be managed with a single cerclage cable. Calcar fractures extending below the lesser trochanter should be scrutinised with additional intraoperative xrays; longer longitudinal cracks can be managed with 2 cables while more complex fractures that exit the diaphysis demand a change to a distally fixed implant and formal fracture reduction. Distal diaphyseal fractures are relatively uncommon in the primary setting, but not rare in the revision setting. When recognised intraoperatively, distal diaphyseal fractures can be treated effectively with cerclage cables. Distal diaphyseal longitudinal cracks noted postoperatively do not typically mandate a return to the OR and instead can be managed with 8 weeks of protected weight bearing.
