Hip arthroplasty following proximal femoral tumour resection in children : the impact of age and articulation on implant survival and the outcomes following acetabular revision.

Abstract

Hip arthroplasty is rarely required before skeletal maturity. However, it is appropriate after resection of a proximal femoral bone tumour. This retrospective single-centre cohort study was conducted to evaluate how age and choice of articulation affects modes of implant failure and revision-free survival, and to understand the longer-term outcomes following inevitable revision. Between January 1982 and April 2023, 60 patients aged between two and 16 years underwent excision of a malignant bone tumour and proximal femoral endoprosthetic reconstruction (PFEPR) combined with either a hemiarthroplasty (HA) or total hip arthroplasty (THA) articulation. The median follow-up was 12.6 years (IQR 4 to 21). There were 41 HAs and 19 THAs. Revision-free survival was poor in pre-adolescent patients (age ≤ 12 years) regardless of articulation (54% at five years (95% CI 38 to 77) and 21% at ten years (95% CI 8 to 54)). Adolescent patients (age > 12 years) undergoing THA (n = 12) had better median, five-year, and ten-year revision-free implant survival (21.9 years (IQR 11.9 to 22.7), 89% (95% CI 71 to 100), and 78% (55 to 100), respectively) than similarly aged patients undergoing HA (n = 15); (7.1 years (IQR 4.9 to 13.5), 68% (95% CI 46 to 100), 39% (18 to 82); p = 0.048), respectively). The leading indication for revision across all ages was an acetabular complication. HA subluxation occurred exclusively in the pre-adolescent cohort (14/26) at a median 2.8 years (IQR 2 to 8). Chondrolysis occurred in the adolescent cohort (8/27) at a median 7.1 years (IQR 2 to 12). Revision THA after failed HA (n = 35) survived well (85% (95% CI 71 to 100) and 77% (60 to 100) at five and ten years) although an early postoperative dislocation rate of 12% (n = 4) was observed, all of which were managed by closed reduction. Very young patients continue have a high risk of further surgery in the first decade after PFEPR. THA combined with PFEPR appears to improve revision-free implant survival in adolescent patients when compared with HA; however, it may introduce a risk of early postoperative dislocation. Following HA, there is a different mode of failure in pre-adolescent compared with adolescent patients, and revision to THA in either circumstance is durable.