Abstract
The clinical results of the cemented Exeter stem in primary hip surgery have been excellent. The Exeter ‘philosophy’ has also been extended into the treatment of displaced intracapsular hip fractures with ‘cemented bipolars’ and the Exeter Trauma Stem (Howmedica).
We have identified an increase in the number of periprosthetic fractures that we see around the Exeter stem. We have also identified a particular group of patients with comminuted fractures around ‘well fixed’ Exeter stems after primary hip surgery that present a particular difficult clinical problem.
Prior to fracture, the stems are not loose, the cement mantle remains sound and bone quality surrounding the reconstruction is good, i.e. classifying it as a Vancouver B1. However the comminuted nature of the fracture makes reduction and fixation with traditional methods difficult. Therefore in these particular circumstances it is often better to manage these as B2 or even B3 fractures, with distal bypass and uncemented reconstruction.
Over an eleven-year period since 1999, 185 patients have been admitted to Nottingham University Hospitals with a periprosthetic femoral fracture around a hip replacement. These patients were identified from a prospective database of all trauma patients admitted to the institution. Of these patients we have identified a cohort of 21 patients (11%) with a periprosthetic fracture around an Exeter polished stem. Hospital notes were independently reviewed and data retrieved. Outcome data was collected with end points of fracture union, re-revision surgery and death. Data was also collected on immediate and long term post-operative complications.
The mean age was 76 years at time of fracture, and 52% were male. The mean duration between primary index surgery and fracture was 18 months (median 11 months).
15 patients were classified as Vancouver B1, and six as B2 fractures. Of the B1 fractures, 14 underwent fixation and one was treated non-operatively. Of the B2 fractures, four were revised, one was revised and fixed using a plate, and one was fixed using a double-plating technique. Prior to fracture, none of the implants were deemed loose although one patient was under review of a stress fracture which subsequently displaced.
One patient died prior to fracture union. All the other patients subsequently went onto unite at a mean of 4 months. There were no deep infections, non- or malunions. No patient underwent further surgery. Dislocation occurred in one patient and a superficial wound infection occurred in one patient which responded to antibiotic treatment. Three other patients have subsequently died at seven, twelve and fifty-three months post fracture due to unrelated causes.
In our series of patients, in addition to the more standard fracture patterns, we have identified a very much more comminuted fracture. Indeed, we have described the appearance as if the tapered stem behaves like an axe, splitting the proximal femur as a consequence of a direct axial load. As a consequence of the injury, the cement mantle itself is severely disrupted. There is significant comminution and soft tissue stripping, calling into question the viability of the residual fragments. Treatment of this type of fracture using a combination of plates, screws and cables is unlikely to provide a sufficiently sound reconstruction. In our experience we believe these fractures around previously ‘well fixed’ Exeter stems should be treated as B2/B3 injuries.
