Abstract
Acetabular fractures, particularly in the geriatric population are on the rise. A recent study indicated a 2.4-fold increase in the incidence of acetabular fractures, with the fastest rising age group, those older than the age of 55. Controversy exists as to the role and indications for total hip arthroplasty (THA), particularly in the acute setting. Three common scenarios require further evaluation and will be addressed. 1.) What is the role of THA in the acute setting for young patients (< 55 years old)? 2.) What is the role and indications for THA in the older patient population (>55 years) and what are surgical tips to address these complex issues? 3.) What are the outcomes of THA in patients with prior acetabular fractures converted to THA?
Acetabular fractures in young patients are often the result of high energy trauma and are a life changing event. In general, preservation of the native hip joint and avoidance of arthroplasty as the first line treatment should be recommended. A recent long-term outcome study of 810 acetabular fractures treated with Open Reduction and Internal Fixation (ORIF) demonstrated 79% survivorship at 20 years with need for conversion to THA as the endpoint. Risk factors for failure were older age, degree of initial fracture displacement, incongruence of the acetabular roof and femoral head cartilage lesions. In selected younger patients, certain fracture types with concomitant injuries to articular surfaces may best be treated by acute THA.
In the elderly patient population, acetabular fractures are more likely the result of low energy trauma but often times result in more displacement, comminution and damage to the articular surface. Osteoporosis and generalised poor bone quality make adequate reduction and fixation a challenge in these acute injuries. As such, the role of acute arthroplasty is becoming more widespread. Consideration should be given to delayed arthroplasty in certain patients to allow time for fracture healing followed by THA. However, early mobilization and weight bearing is important in the elderly population and consideration should be given to acute THA. The challenge remains gaining appropriate acetabular fixation in the fractured, osteoporotic bone. Early results showed high complication rates with acetabular fixation. However, newer fixation surfaces and advances in ORIF techniques have led to improved results. In addition, the need for complex acetabular reconstruction with the use of cages or cup cage constructs may be required in this setting. Appropriate 3-D imaging is essential to evaluate the extent of involvement of the anterior and posterior columns as well as the acetabular walls. Mears et al. reported on 57 patients who underwent THA for acute acetabular fracture and reported results at a mean of 8.1 years. 79% of patient reported good or excellent results and no acetabular cups were revised for loosening.
One of the more common scenarios is the patient that presents with a prior ORIF of an acetabular fracture that has developed post-traumatic arthritis or avascular necrosis of the hip and requires conversion to THA. Challenges in this patient population include dealing with prior hardware that may interfere with THA component fixation, severe stiffness of the joint making exposure difficult and prior heterotopic ossification that may put neurovascular structures at risk. Previous studies have demonstrated lower long-term survivorship of the acetabular component (71% at 20 years) compared to primary THA for osteoarthritis. New acetabular fixation surfaces should mitigate the risk of aseptic loosening in this challenging patient population.
