Factors associated with failure of fixation of Vancouver B fractures around a cemented polished tapered stem: A 5 to 14 year follow up study.

AIMS

There is increasing evidence for fixation as opposed to revision for Vancouver B fractures around polished taper slip stems, however it is remains unclear whether fixation is associated with stem loosening in the longer term. This study aims to assess survival of plate-fixation of Vancouver-B-fractures around a polished-taper- slip cemented stem and identify factors associated with failure.

METHODS

Retrospective cohort study assessed 129 consecutive unilateral Vancouver-B-fractures around cemented Exeter stems at a minimum of 5 years following open-reduction-internal-fixation (ORIF) with unilateral non-locked unilateral plating+/-cerclage cables. The primary outcome measure was reoperation for any reason. Kaplan Meier survival analysis was performed.

RESULTS

Fractures (B1 n = 31 (24%); B2 n = 91 (71%); and B3 n = 7 (5%)) occurred at median of 6 years (IQR 1.2-9.2) after primary surgery. Mean patient age was 78.2 (SD10.56, range 46-96) and 54 (42.9%) were female. Mean follow up was 8.7 years (SD 2.48, 5.7 to 14.4). Symptomatic femoral stem loosening requiring revision occurred in two B2 fractures of metaphyseal split and short spiral patterns. The most common mode of failure was non-union (n = 7, 5%). Both fixation failure (n = 6/31 Vs n = 3/91 vs n = 0/7, p = 0.008) and reoperation (n = 8/31 vs n = 6/91 vs n = 0/7, p = 0.008) were significantly higher following fixation of B1 fractures compared to B2 and B3 fractures. Overall 5year survival free from reoperation was 88.8% (82.0-94.7 95%CI). B1 fracture types were associated with an increase risk of failure (endpoints fixation failure p = 0.010; and reoperation p = 0.016). Transverse fractures (B1) were associated with a relative risk of reoperation of 4.22 (1.63-10.9 95% CI, p = 0.008).

CONCLUSION

Fixation of Vancouver-B fractures around cemented Exeter stems, when the bone-cement interface is intact and the fracture is anatomically reducible, had an excellent 5-year survival. Only 2 (1.6%) cases of late femoral stem loosening occurred, however, B1 type transverse fractures were associated with a higher rate of reoperation.