Key Objectives:

  • Validate the recently developed Twente Lower Extremity Model (TLEM) further and use innovative measurement methods to acquire unique validation data.
  • Apply and validate 4-D shape measurements on patients, as an improvement to conventional marker-based movement analysis systems.
  • Generate a patient-specific representation of the lower limb using innovative imaging techniques and fast computer algorithms.
  • Add new features to TLEM such that it can incorporate adaptive capabilities of patients that require complex M-S surgery.
  • Create a computer program of the patient-specific model which allows the surgeon to pre-plan and execute the surgery, as well as an interface which can be used during surgery.
  • Develop a surgical simulator that can be used as a training method for reconstructive surgeons.


To reach the project main goal, the following quantifiable objectives can be formulated:

Objective 1: The starting point for this research is a musculo-skeletal computer representation of the lower extremity. For this aim we will use the Twente Lower Extremity Model (TLEM) which is recently developed. The aim is to validate the TLEM model further for other activities than normal walking and use innovative measurement methods to acquire unique validation data.

  • The model should predict the measured quantities within 10% accuracy (external forces, EMG, FDG-PET scan, NIRS and ultrasound comparison).
  • Correlations between model predictions and actual measurements should be higher with the patient-specific models as compared to a generalized model.

Objective 2: Kinematic measurements are commonly performed using markers on the body segments and multiple CCD cameras that can calculate the segmental positions, velocities and accelerations. However, the application of markers can sometimes be burdensome for patients. In this project we want to apply and validate 4-D shape measurements (3-D shape varying in time) on patients. One could compare it to ‘dynamic body scans’. This is a very innovative technique and, if successful, will reduce the burden for patient measurement.

  • The overall accuracy should not deviate more than 5% of traditional Vicon measurements
  • The sample frequency should be in the order of 50 Hz
  • The experimental set-up time and costs should be comparable to the Vicon system

Objective 3: Add new features to the TLEM model such that it can incorporate adaptive capabilities of patients that require complex muscuslo-skeletal surgery. This is necessary as computer models typically cannot predict the functional outcome after the surgery as they ignore the adaptive capacity of the human body. In this project the adaptive capacity of the patients is quantified and incorporated in the muscuslo-skeletal model.

  • Implementation of the adaptive capacity of patients should reduce errors in the predicted effect of the surgery by a factor of 2.

Objective 4: To generate a patient-specific representation of the lower limb. Using innovative imaging techniques and fast computer algorithms a patient-specific parameterization of the patient is made which enables the creation of a musculo-skeletal model. Image based 3-D parameterization should be:

  • Fast - within an hour rather than days/weeks as is currently the case
  • Accurate - the geometrical errors should in general be less than 1 cm the geometrical errors (in terms of muscle insertion points, muscle length moment arms) should have a small effect (less than 10%) on the functional outcome as predicted by the musculo-skeletal model

Objective 5: Create an informative-communicative computer program of the patient-specific computer model which allows the surgeon to pre-plan and execute the surgery to achieve the best functional outcome for the patient in the safest way.

  • The software should allow surgeons to pre-plan the optimal surgical intervention within 30 minutes (this includes the analysis of multiple surgical scenarios and the prediction of the functional outcome for all these scenarios)

Objective 6: Create an interface of the pre-operative plan and the navigation system which can be used during the actual surgery and allows for safe surgery:

  • The navigation system should be completely compatible with the virtual pre-plan module. Hence, fully automatic and instant uploading of the optimal surgical plan should be possible.
  • 3-D precision (of for example a muscle transfer in mm, or a bone cut in mm) quantification will be performed; errors should be less than 3 mm.
  • The navigation module that guides the surgeon through the operation should result in a surgical time that does not cost more than 15 minutes relative to the non-navigated operation.

Objective 7: To develop a surgical simulator that can be used as a training modality for reconstructive surgeons so that young surgeons are trained in a virtual environment, allowing them to generate experience and comprehension of musculo-skeletal surgery and its complications.

  • The surgical simulator should be fast and calculate functional effects of the changes to the musculo-skeletal model as made by the trainees within 1 minute

Additional information