Tapered fluted titanium stems in the management of Vancouver B2 and B3 periprosthetic femoral fractures

Abstract

Background: Surgeons have several implant choices when managing Vancouver B2 and B3 periprosthetic fractures about the hip. Few long-term studies have reported outcomes for tapered fluted titanium stems.

Questions/purposes: We determined (1) survival, with femoral revision as the end point, of distal taper stems in the treatment of Vancouver B2 and B3 periprosthetic fractures at our institution, (2) radiographic outcomes, and (3) quality of life and hip function after revision.

Methods: Of the 200 patients with Vancouver B2 or B3 periprosthetic fractures treated with femoral revision between February 2000 and February 2010, 55 (38 B2, 17 B3) were treated with modular tapered titanium stems. Of the surviving 47 patients, one was lost to followup, leaving 46 (30 B2, 16 B3) available for review at a mean of 54 months (range, 24-143 months). Initial indications for using these implants were treatment of periprosthetic fractures where less than 4 cm of diaphyseal fit was available, but this evolved during the study period to all fractures unless no diaphysis remained, in which case complex revision techniques were used. Radiographs were assessed to establish fracture healing, stem subsidence, and bone stock restoration. Quality of life and hip function were assessed using WOMAC, Oxford, SF-12, UCLA activity level, and satisfaction scores.

Results: Two femoral stems were revised: one subsided and was revised at 12 months; the other had deep infection and underwent two-stage revision at 49 months. Radiographic review showed one nonunion, with maintenance or improvement of bone stock in 89% of patients. Subsidence occurred in 24%. Mean Oxford score was 76 of 100, WOMAC function and pain scores were 75 and 82 of 100, satisfaction score was 91 of 100, and SF-12 mental and physical scores were 53 and 40 of 100.

Conclusions: We report encouraging short-term results in terms of survival of distal taper stems in the treatment of B2 and B3 periprosthetic fractures. Although subsidence was frequent, most migrated less than 3 mm without correlation to poor pain and functional scores.

Fig. 1A–C

Photographs show the ZMR^® and Revitan^® stems: (A) ZMR^® stem with a 3.5° taper and (B, C) two sizes of the Revitan^® stem and modular bodies with a 2° stem taper.

Fig. 2A–D

Images illustrate revision of a Type B2 fracture using a 14-mm-diameter tapered fluted modular titanium stem. (A) A preoperative radiograph shows a fracture around a loose cemented stem. (B) An initial postoperative view shows position of the tapered stem. (C) The undersized stem has clearly subsided. (D) The patient was revised to a 20-mm stem and had excellent results at 12 months. A constrained liner had been used because of severe abductor deficiency and high risk of dislocation.

Fig. 3A–C

Images illustrate revision of a Type B3 fracture with an allograft strut in a 63-year-old woman. (A) An AP radiograph of the femur demonstrates a fracture around a cemented stem with an extensive cement mantle. After removal of the cement, there was severe bone loss. (B) An immediate postoperative view shows the tapered stem with allograft to restore lateral bone stock. (C) Eight years later, the fracture has not united, but the onlay allograft has united to the femur. There is obvious bone loss (Type A) around the proximal implant. Her cup acetabular cage construct was revised for loosening and pelvic discontinuity by plating the posterior column and using an enhanced fixation surface cup.

Fig. 4A–C

Images illustrate revision of a Type B3 fracture in an 83-year-old woman. (A) An AP radiograph of the femur demonstrates a fracture with osteolysis of the proximal femur. (B) An initial postoperative view shows allograft postioned medially with thinning of the cortical bone. (C) Followup at 34 months shows recovery of proximal bone and incorporation of the allograft strut. Despite the subsidence of the stem, the patient was asymptomatic.