Although the overall rate of periprosthetic femur fractures associated with THA is unknown, it appears to be increasing [21
]. Estimates in the literature range from 0.1 to 2.1% for postoperative fractures and from 0.3 to 5.4% for intraoperative fractures [14
]. Postoperative fracture rates are generally higher for revision THA compared to primary THA, whereas intraoperative rates are generally higher for uncemented THA compared to cemented THA.
The treatment of periprosthetic femur fractures after THA has historically been associated with a high rate of treatment failures, complications, and unsatisfactory outcomes. Difficulty arises in comparison of various results in the literature due to differences in length of patient follow-up, patient demographics, types of implants used, the number of revision arthroplasties, the types of operative techniques employed, and variable outcome measures utilized. To date, no prospective randomized trial studying treatment interventions has been performed. It has been the work of Duncan and Masri [17
] that has clearly aided in the classification and recommendation for treatment of these complex fractures. According to these authors, treatment is guided by the classification system, with type A fractures generally being treated nonoperatively or with cerclage fixation. Type B1 fractures can be treated by ORIF with plate devices and or the use of cortical strut grafts. Type B2 fractures usually require revision to a long-stem femoral component, with or without additional extramedullary fracture fixation. Type B3 fractures, in addition to revision of the femoral stem, generally require the use of significant allograft in an attempt to reestablish bone stock. Type C fractures can usually be treated by ORIF with standard plate systems or fixed angle plate devices. While these recommendations occurred after the onset of our study, our results appear to be consistent with what these authors have found.
The results of this series are similar to those from previous reports and reflect the difficulty in treating periprosthetic fractures of the femur after THA. In this study, 74% of patients achieved fracture union after the primary treatment, whereas another 12% united the fracture after undergoing further surgical treatment, for a final fracture union rate of 86%. Complications relating to surgical treatment occurred in 19 patients, for a rate of 29% confirming the complicated nature of this type of surgery including several patients with multiple complications. There are several limitations inherent to this type of review including different biases towards treatment over the study time period and the limited number of study patients within some groups. However, clearly some trends are worth noting.
While not statistically significant, among the type B1 fractures, those treated with ORIF and the use of a plate plus a cortical strut graft had a higher healing rate (seven of eight, 88%) than those treated with a plate device alone (six of nine, 67%), although the numbers are small in this subgroup. There has been support in the recent literature for use of onlay allograft cortical struts [4
], as well as animal studies investigating the use of osteogenic proteins to enhance strut allograft healing [24
In the B2 group the success rate with cemented revision (11 of 13, 85%) was equivalent to that of uncemented revision (four of five, 80%). Not surprisingly, our type B3 fractures were associated with the highest complication rates (66%) in our series, as might be expected given the difficulty of surgical reconstruction of many of these fractures. Cemented femoral revision was surprisingly successful in this subgroup, with five of six patients (83%) healing and having a stable femoral component at latest follow-up. Of note, while both patients in whom ORIF was performed gained union, the implants were still both loose at follow-up, making the patients potentially at risk for fracture. Currently, we would recommend revision of the implant.
In the C group of patients, it was interesting to note that union was difficult to obtain regardless of treatment (50%). Clearly, patient factors such as osteopenia and the effect of stress shielding may play a role in getting these fractures to unite. Consideration of adjuvant bone grafting as well as potential use of bone enhancing agents should be given at the time of surgery.
A clear trend was that patients with RA or JRA fared much worse than the overall group. In addition to having compromised immune systems due to the effects of various disease-modifying agents, these patients also frequently had poor bone stock. Of 16 patients, only eight successfully healed after initial treatment. Six fractures ultimately went on to become nonunions, with two patients being converted to total femur replacement due to recurrent infection, nonhealing, and bone loss. Total femur replacement following periprosthetic fractures in RA patients has also been previously reported in the literature [25
]. Three patients sustained a refracture and 6 of the 16 (38%) had one or more infections. These high complication rates highlight the risk to RA and JRA patients whose underlying disease can compromise treatment outcomes.
Recently, authors at the Mayo clinic reported the results of revision arthroplasty for 118 hips with Vancouver type-B fractures [11
]. The femoral implants used in this series included cemented stems, proximally porous coated uncemented stems, extensively coated stems, and allograft-prosthetic composites. Overall, Kaplan–Meier analysis showed a 5-year survival rate of 90% and a 10-year rate of 79.2%. They concluded that the best results were seen when an uncemented and extensively porous coated stem was used. There have also been recent reports demonstrating good results with the use of Wagner-type fluted tapered stems for the treatment of Vancouver type-B fractures [12
]. The patient numbers were small in these two studies, however.
Beals and Tower [1
] reported the results of 93 periprosthetic fractures treated at numerous facilities by multiple surgeons. Overall, outcomes were considered excellent in 32% of cases, good in 16%, and poor in 52%. Most fractures except trochanteric fractures had a poor result with nonoperative treatment. They also found that the results of ingrowth revision were superior to those for cemented revision for all fracture types. The complication rates were 41% relating to the fracture and 33% relating to the arthroplasty.
Sledge and Abiri [2
] reported on seven patients with Vancouver B2 fractures treated in a standardized manner with removal of the implant, cerclage wiring of the fracture with allograft struts, and implantation of a long, uncemented stem. A modular, proximally loading implant was used in three cases, and a curved, fully porous-coated stem was used in four cases. At 33 months average follow-up, they reported no failures, no refractures, and an average Harris hip score of 83. All patients except one returned to their preoperative ambulatory status. They did not comment on complications.
Enthusiasm for operative treatment of complex periprosthetic fracture gained popularity based upon the work of Mont and Maar [26
], whose meta-analysis of 26 published reports looked at periprosthetic fractures in 487 patients. While comparisons are difficult due to a lack of uniformity in fracture classification and reporting of outcomes, they found the most satisfactory outcomes for type 2, 3, and 4 fractures (around the tip of the stem) with cerclage fixation or long-stem revision. Screw/plate fixation and nonoperative treatment with traction generally lead to unsatisfactory outcomes. Highly comminuted type 5 fractures appeared to be best treated with long-stem revision.
Our results demonstrate good success rates in treating the majority of periprosthetic femur fractures. However, surgeons should be alerted to the high rate of complications in this group. When presented with a periprosthetic fracture, we feel that the Vancouver classification system provides excellent stratification and uniform terminology. In addition, our data support the treatment algorithm recommended by the Vancouver group. While one of the limitations of this study includes small numbers of subjects, especially in the nonoperative treatment groups, we believe that depth of analysis of the surgical group provides ample support for our conclusions. Future studies employing prospective randomized trials should be conducted in an attempt to confirm classification systems and outcome measures. However, based upon our data, we recommend the use of the Vancouver classification system and treatment algorithm for these difficult fractures.