# Risk-Stratified Predictive Analysis of Docking Site Outcomes in Lower Extremity Bone Transport: Identifying High-Risk and Low-Risk Zones for Large Segmental Defect Management

## TL;DR

This study identifies factors that predict the need for a docking site procedure during bone transport in lower extremities, helping improve treatment planning.

## Contribution

The study introduces transport duration and speed as strong predictive factors for the need of a docking site procedure in bone transport.

## Key findings

- Transport speed and duration were strong predictors of the need for a docking site procedure.
- A transport duration exceeding 290.5 days significantly increased the likelihood of requiring a docking site procedure.
- Age and vascular injury were also significant predictors of docking site necessity.

## Abstract

Background: Reconstruction of limbs with extensive bone loss often requires complex surgical procedures, which can be technically demanding, time-consuming, and physically and psychologically burdensome for patients. Historically, the lack of alternatives for large bone defects often led to primary amputation. Modern musculoskeletal practice allows for reconstruction using autologous or allogeneic bone grafts, or through more complex procedures such as the Masquelet technique or distraction osteogenesis. However, these methods share a common challenge: the need for a docking site procedure in cases of insufficient bony fusion of the transport segment. The aim of this study was to identify predictive factors for the need for a docking site procedure. Methods: A retrospective analysis was conducted on 93 patients treated for lower extremity bone defects between January 2013 and June 2023. Of these, 39 patients (41.9%) underwent segmental bone transport and formed the study cohort for the predictive model analysis. Patients of all ages and both genders were included, regardless of the etiology and size of the defect. The need for a docking site procedure was analyzed using logistic regression, ROC analysis, and ANOVA. Results: The study included 93 patients (73 male, 19 female) aged 7 to 83 years. The mean defect size was 76.46 mm (range: 12.1 to 225.1 mm). The mean transport duration was 149.97 days, with a mean transport speed of 0.61 mm/day. Among the 39 segmental transport patients, a docking site procedure was performed in 64.1% (n = 25). Logistic regression and ROC analysis were performed on this subgroup (n = 39, with 25 events). Significant predictors for the need for a docking site procedure were age (p = 0.024), vascular injury (p = 0.009), transport duration (p = 0.001), and transport speed (p < 0.001). ROC analysis demonstrated that transport speed (AUC = 0.931) and transport duration (AUC = 0.911) showed strong discriminative ability for predicting docking site procedure necessity, suggesting potential utility as clinical decision-support parameters. Conclusions: The study identified transport duration and speed as potentially valuable predictive factors in this retrospective cohort for the need of a docking site procedure, though prospective validation is required. A transport duration exceeding 290.5 days significantly increased the likelihood of requiring a docking site procedure. These findings can help optimize treatment planning and improve long-term limb preservation.