Hip arthroplasty following proximal femoral tumour resection in children

Aims: 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. Methods: 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). Results: 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. Conclusion: 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.