How Often Does Spindle Failure Occur in Compressive Osseointegration Endoprostheses for Oncologic Reconstruction?

Area of Science:

• Orthopedic Oncology
• Biomaterials Science
• Surgical Reconstruction

Background:

• Compressive osseointegration is a key technique for limb salvage in distal femoral oncologic tumor cases.
• Limited data exists on short-term survival and failure risk factors for distal femur compressive endoprostheses.

Purpose of the Study:

• To determine the frequency of spindle failure in distal femoral reconstructions using compressive osseointegration.
• To identify characteristics and risk factors associated with mechanical and rotational failures.
• To explore other failure modes and revision causes in these reconstructions.

Main Methods:

• Retrospective review of 116 distal femur reconstructions using Compress® prosthesis (1996-2013).
• Analysis of failure modalities, including spindle and rotational failures, through radiographs and clinical data.
• Evaluation of risk factors (age, BMI, resection length, chemotherapy) using survival analysis (Kaplan-Meier) and Cox proportional hazard modeling.

Main Results:

• Five- and 10-year spindle survival rates were 91% and 91%, respectively.
• Five- and 10-year rotational failure survival rates were 92% and 92%, with most early failures linked to twisting injuries.
• No significant risk factors were identified for mechanical failure; 5-year revision-free survival was 57%.

Conclusions:

• Distal femur compressive osseointegration is a viable reconstructive method for oncologic cases.
• Rotational failures are infrequent and typically occur early post-operatively.
• Further investigation is needed to mitigate mechanical/rotational failures and address other revision causes like infection.