Risk factors for periprosthetic femoral fracture
Introduction
Periprosthetic femoral fracture is a devastating complication after total hip arthroplasty and is associated with a high rate of postoperative complications and often a poor clinical result.20, 35 Moreover, the mortality rate after periprosthetic femoral fracture is alarmingly high.4 For these reasons it is important to identify risk factors that lead to fracture. Mont and Maar found most studies in their review of the literature to be small and varied in the type of data reported.28 Another challenge is the relative lack of studies of late fractures after cementless implants.38 More recent clinical studies and published registry data have contributed to our understanding of the aetiology of late periprosthetic fracture, and have led to identification of several risk factors.
Section snippets
Trauma
The mechanism of periprosthetic fracture has been frequently investigated.1 Not surprisingly, the majority of the time, low-energy falls are the traumatic event that causes the fracture.23, 31 Minor trauma, or falls at the same level at which the patient had been sitting or standing, accounted for approximately 75% of periprosthetic fractures in patients in the Swedish registry database.23 Again highlighting the lack of quality bone stock remaining after multiple procedures, spontaneous
Age
Age is frequently cited as a risk factor for late fracture. Related to remaining bone quality, previous surgery, and medical comorbidities, the risk imparted by age is probably multifactorial,21 and evidence supporting age as a risk factor varies widely. Among studies investigating the age of patients sustaining fractures, reported mean ages have been ranged from 60 to 77 years. Age is associated with other problems like osteoporosis and falls which put the patient at greater risk.
Wu reviewed
Gender
A higher proportion of periprosthetic fractures among female patients has been reported.1, 3, 15, 37 Reported percentages of fractures in females in these studies have ranged from 52% to 70%. As a result of these numbers, Tsiridis claimed that gender was a risk factor for postoperative fracture.36 The significance of gender is probably multifactorial, as it also is associated with osteoporosis and remaining structural bone. Swedish joint registry data show an almost equal gender distribution in
Osteoporosis
Osteoporosis is a generally accepted risk factor for late periprosthetic femoral fracture.10, 17, 19, 21 However, few studies have systematically investigated the effect of the patient's bone quality on subsequent fracture risk. Wu 1999 looked at 16 postoperative fractures in a series of 454 consecutive arthroplasties.38 Using Singh's index of osteoporosis, preoperative osteoporosis was found to be a significant predictor of fracture risk. Beals and Tower found that 38% of patients in their
Index diagnosis
Different diagnoses often lead to specific patient care decisions. Similarly, the patient diagnosis prior to hip arthroplasty has been demonstrated to impart some degree of risk for periprosthetic fracture.
Rheumatoid arthritis is often associated with diffuse osteopenia and other medical comorbidities. In the Swedish registry, rheumatoid arthritis was overrepresented in the group of patients sustaining periprosthetic fracture.23 In addition, when evaluated as a risk factor, rheumatoid arthritis
Osteolysis
Osteolysis by itself is frequently cited as a risk factor for late periprosthetic femoral fracture.29, 32, 36 Described by Harris, localised femoral bone loss in association with a loose cemented stem was thought to be mediated by the failed cement.11 Now recognised to be the end result of a response to wear particles, osteolysis is still an enormous problem in both cemented as well as cementless hip arthroplasty.24, 25
The most common cause of late periprosthetic fracture is osteolysis and the
Aseptic loosening
Aseptic loosening is typically mediated by osteolysis, but the two terms are often used interchangeably. Loosening of femoral stems as a result of osteolysis is characterised by localised or diffuse endosteal bone resorption.
Loose implants have been demonstrated to be risk factors for periprosthetic fracture in several studies.13, 36 Bethea et al. suggested that loosening of the stem led to increased motion at the cement–bone interface, resulting in further bone resorption.3 In their series of
Revision
Revision total hip arthroplasty is frequently associated with bone loss and challenging implant fixation. Wear debris and resultant osteolysis can reduce available bone stock for fixation at the time of revision. In addition, cortical perforation may occur during cement or implant removal, thus compromising remaining bone integrity. For these reasons, when investigated independently, revision has been identified as a risk factor for periprosthetic fracture.21
Several studies have confirmed the
Implants
Different implants have also been shown to impart different levels of late periprosthetic fracture risk depending on specific design characteristics. These differences have been found mainly among cemented stems, as countries where cement is the predominant means of fixation also have the largest series of periprosthetic fractures. From the Finnish registry, Sarvilinna et al. found the Exeter stem to be associated with an increased risk of late fracture compared with all other stems.30 Data
Technique
Any surgical factor that decreases bone strength is a risk factor for late fracture. These include screw holes and stress risers from adjacent implants.7, 32 Cortical perforations may result from osteolytic lesions, previous hardware or during cement or implant removal. McElfresh and Coventry described reaming of the femoral canal, osteoporosis, a narrow medullary canal and previous prosthesis or osteotomy as factors increasing the chances of creating a cortical perforation.27
These defects can
Prevention
Prevention of late periprosthetic femoral fracture is best accomplished through routine clinical and radiographic follow-up.21 Regular monitoring of patients allows for early detection of osteolysis and aseptic loosening, and thus facilitates timely revision surgery.32
Several technical factors can help prevent late fracture. Great care must be taken when reaming the canal or removing cement in patients with known risk factors for fracture, such as rheumatoid arthritis, or those patients who
Conclusions
Given the variable results of treatment for late periprosthetic femoral fracture, every means necessary to prevent this complication must be undertaken. The surgeon must keep in mind patient factors that increase the chance of fracture, including age, gender and index diagnosis. Compromised bone stock in both complex primary and revision surgery must be addressed. Finally, routine follow-up of patients after total hip arthroplasty is critical in identifying those at high risk of fracture.
Conflict of interest statement
Dr. Franklin has no financial relationship with any member of the orthopaedic industry.
Dr. Malchau has a financial relationship with Zimmer, Biomet, and Smith and Nephew.
References (36)
Periprosthetic fractures associated with osteolyis: a problem on the rise
J Arthroplasty
(2003)- et al.
The Charnley versus the Spectron hip prosthesis: clinical evaluation of a randomized, prospective study of 2 different hip implants
J Arthroplasty
(1999) - et al.
The Charnley versus the Spectron hip prosthesis: radiographic evaluation of a randomized, prospective study of 2 different hip implants
J Arthroplasty
(1999) - et al.
The prevention of periprosthetic fractures in total hip and knee arthroplasty
Orthop Clin North Am
(1999) Femoral fractures associated with total hip arthroplasty
Orthop Clin North Am
(1992)- et al.
Periprosthetic femoral fractures: classification and demographics of 1049 periprosthetic femoral fractures from the Swedish National Hip Arthroplasty Register
J Arthroplasty
(2005) - et al.
Fractures of the ipsilateral femur after hip arthroplasty. A statistical analysis of outcome based on 487 patients
J Arthroplasty
(1994) - et al.
Periprosthetic fractures of the femur
Orthop Clin North Am
(2002) - et al.
Fractures of the femur after hip replacement: the Oregon experience
Orthop Clin North Am
(1999) - et al.
The management of periprosthetic femoral fractures around hip replacements
Injury
(2003)