Uncemented slotted stem versus short stem for distal femoral endoprosthetic reconstruction in pediatric bone tumor patients: a retrospective analysis of prosthetic performance and functional outcomes.

BACKGROUND

Uncemented endoprosthetic reconstruction is commonly used in pediatric patients after distal femoral tumour resection. However, conventional short stems may be associated with aseptic loosening, bone resorption, and end-of-stem pain, which may compromise long-term outcomes. This retrospective cohort study aimed to compare prosthetic loosening, bone resorption, and clinical outcomes between slotted stems and conventional short stems in pediatric patients undergoing uncemented distal femoral endoprosthetic reconstruction.

METHODS

We performed a retrospective cohort study of pediatric patients who underwent implantation of an uncemented endoprosthesis with either a slotted stem or a conventional short stem between 2021 and 2023. Aseptic loosening and bone resorption were evaluated radiographically using radiolucent lines, stem axis displacement, and translucent bands. Clinical outcomes were assessed using the 1993 Musculoskeletal Tumor Society (MSTS-93) score and the rate of end-of-stem pain. Complications and endoprosthetic failures were also recorded.

RESULTS

A total of 47 patients were included, including 24 in the slotted stem group and 23 in the control group. The median age was 9 years (range, 8-14) in the slotted stem group and 10 years (range, 7-14) in the control group. The median follow-up was 35 months (range, 24-49) in the slotted stem group and 36 months (range, 25-48) in the control group. No significant between-group difference was observed in the rate of radiographic aseptic loosening (4.17% vs. 8.70%, p = 0.609) or in bone resorption in Zones 1-4. However, the slotted stem group had less bone resorption in Zone 5 (p = 0.022). MSTS-93 scores were similar between groups (p = 0.574), whereas the slotted stem group had a lower rate of end-of-stem pain (p = 0.048).

CONCLUSIONS

In this retrospective cohort, the slotted stem showed comparable short-term outcomes to the conventional short stem, with less Zone 5 bone resorption and a lower rate of end-of-stem pain. Slotted stems are viable alternatives to short stems for distal femoral endoprosthetic reconstruction following tumour resection in pediatric patients.