Applications

This device is of interest to :

Orthopedic surgeons, to help them better analyze injuries to the ACL but also to perform follow-up on their ligamentoplasties (repair of the ACL).

Centers and departments of Physical Therapy and Rehabilitation as well as independent physical therapists, for pre- and post-operative care.

Physicians specializing in Sports Medicine.

Doctors’ offices and Emergency Rooms, to provide early detection.

And finally, professional sports clubs, (football, basketball, handball, volleyball, rugby...) to use during the recruitment of new players.

The Technique

The GNRB is a device that measures the sagittal translation of the tibia at 20° of flexion to reproduce the Lachman position. The leg rests on a thermoformed shell that can be adapted to the length of each patient’s leg; the foot is held at a rotation of 0°. An electric jack exerts several levels of pressure on the calf, at the examiner’s discretion: 67 N, 89 N, 134 N, 150 N ou 250 N. Surface electrodes applied to the posterior surface of the thigh ensure that there is no hamstring muscle activity for the knee being tested (feedback effect). A motion sensor (precise to 0.1 mm) records the anterior drawer shift of the anterior tuberosity of the tibia in relation to the femur. The drawer shift for each pressure level chosen as well as the shift / pressure curve are recorded on a remote PC. Each patient has his own electronic file in which laxity measurements are recorded, as are the specific testing conditions: the tightening force on the thigh, the level of pressure exerted and the results (shift / pressure curves, extension, stiffness). The system is piloted by a microcalculator that ensures the consistency and precision of the measurements. Comparison tests are performed on each knee; the patient lies on a standard examining table.

The innovative nature of this device lies in the possibility of detecting differences in tibial shift between the two knees, indicating a partial tear, thanks to the precision of the measurements and to the simultaneous recording of muscle activity. All data are recorded automatically in the patient’s electronic file.

The GNRB offers many advantages compared to other arthrometers:

1. A simple, non-invasive and painless system,

2. Precise to 0.1 mm,

3. Hamstring muscle activity is taken into account,

4. Reading and recording on a remote PC,

5. Sensitivity and specificity > 90 %,

6. Reproducibility.