Fatigue failure of the cephalomedullary nail: revision options, outcomes and review of the literature.

Abstract

Cephalomedullary nail (CMN) failure is a rare entity following hip fracture treatment. However, it poses significant challenges for revision surgery, both mechanically and biologically. Nail failure rates have been reported at <2%; however, no published studies have reported revision surgery procedures and their respective outcomes. We present a regional experience, with outcomes, of the revision options. We identified 20 fatigued CMNs that underwent four different revision procedures. Mean age was 73±15.24years, with a 3:1 female preponderance, and a median ASA grade of 3. Post-operative CMN radiographs demonstrated a significant number of fractures were fixed in varus, with reductions in neck-shaft angles post-operatively. A "poor" quality of reduction resulted in significantly earlier nail failure, compared to "adequate" and "good" (p=0.027). Tip-Apex Distance (TAD) mean was 23.2±8.3mm, and an adequate TAD with three-point fixation was seen in only 35% of cases. Mean time to failure was 401.0±237.2days, with mean age at failure of 74.0±14.8years. Options after failure included revision CMN nail, proximal femoral locking plate (PFLP), long-stem or restoration arthroplasty, or femoral endoprosthesis. Barthel Functional Index scores showed no significant difference at 3 and 12months post-operatively, nor any difference between treatment groups. Mean 12-month mortality was 30%, akin to a primary hip fracture mortality risk according to NICE guidelines. Mortality rates were lowest in revision nails. Subsequent revision rates were higher in the PFLP group. There is no reported evidence on the best surgical technique for managing the failed CMN, with no clear functional benefit in the options above. Good surgical technique at the time of primary CMN surgery is critical in minimising fatigue failure. After revision, overall mortality rates were equivalent to reported primary hip fracture mortality rates. Further multicentre evaluations are required to assess which technique convey the best functional outcomes without compromising 12-month mortality rates.