Survival and failure modes of the Compress® spindle and expandable distal femur endoprosthesis among pediatric patients: A multi‐institutional study

Abstract

Background: Expandable endoprostheses can be used to equalize limb length for pediatric patients requiring reconstruction following large bony oncologic resections.Outcomes of the Compress ® Compliant Pre-Stress (CPS) spindle paired with an Orthopedic Salvage System expandable distal femur endoprosthesis have not been reported. Methods:We conducted a multi-institutional retrospective study of pediatric patients with distal femoral bone sarcomas reconstructed with the above endoprostheses. Statistical analysis utilized Kaplan-Meier survival technique and competing risk analysis.Results: Thirty-six patients were included from five institutions. Spindle survivorship was 86.3% (95% confidence interval [CI], 67.7-93.5) at 10 years. Two patients had a failure of osseointegration (5.7%), both within 12 months. Twenty-two (59%) patients had 70 lengthening procedures, with mean expansions of 3.2 cm (range:1-9) over 3.4 surgeries. The expandable mechanism failed in eight patients with a cumulative incidence of 16.1% (95% CI, 5.6-31.5) at 5 years. Twenty-nine patients sustained International Society of Limb Salvage failures requiring 63 unplanned surgeries. Periprosthetic joint infection occurred in six patients (16.7%). Limb preservation rate was 91% at 10 years.Conclusions: There is a high rate of osseointegration of the Compress ® spindle among pediatric patients when coupled with an expandable implant. However, there is a high rate of expansion mechanism failure and prosthetic joint infections requiring revision surgery.

A Successful Clinical Outcome 29 Months Following Improper Placement of the Compress Implant

“…In both cases, revision surgery was successful at obtaining osseous integration. The most common reason for revision was for infection which occurred in 6 of 36 patients at a mean time of 44 months 9 . This patient is nearly 3 years out from the index surgery without evidence of failure at the bone-implant junction, suggesting that this patient is outside the window of commonly seen osseous integration failure.…”

Femoral Magnetic Lengthening After Distal Femur Endoprosthetic Reconstruction in a Pediatric Patient

“…Furthermore, a long length of otherwise normal bone would be removed to implant an expandable prosthesis of appropriate lengthening potential. Prior studies have demonstrated that expandable prostheses have high failure rates ranging from 63% to 78%, typically requiring 2 additional surgeries unrelated to lengthening 8,10 .…”

“…Endoprosthetic reconstruction can complicate options to correct limblength discrepancy because of the presence of implant stems and risk of prosthesis infection. Expandable prostheses exist but have high rates of reoperation and failure 1,[8][9][10] . In addition, sufficient bone must be removed for the expandable portion of the implant, creating additional challenges in patients with growth potential.…”

What’s New in Musculoskeletal Tumor Surgery

“…The authors demonstrated lower mean implant survival time in patients who underwent high-dose radiation compared with patients who underwent no radiation. Tanaka et al performed a multi-institutional review of pediatric patients with distal femoral bone malignancies who underwent reconstruction with the Compress Compliant Pre-Stress spindle (Zimmer Biomet) paired with an Orthopedic Salvage System expandable distal femoral endoprostheses (Zimmer Biomet) 27 . The authors found high rates of osseointegration of the Compress spindle but high rates of failure of the expandable endoprosthetic device.…”