GNRB® Knee Arthrometer
The original automated knee arthrometer from Genourob — applying precisely defined forces to generate objective, reproducible ACL compliance curves via the LDA® method. The clinical and research foundation for over 15 years of peer-reviewed knee laximetry studies.
Description
The GNRB® is the automated knee arthrometer that established the LDA® (Laxity Displacement Analysis) method — the quantitative approach to measuring anterior tibial translation that underpins over 15 years of peer-reviewed research across Europe, the Middle East, Australia, and beyond.
Unlike manual arthrometers (KT-1000, Rolimeter), the GNRB® applies precisely defined forces to the tibia automatically, with no examiner hand contact during the measurement itself. The result is a force-displacement compliance curve — not a single displacement number — from which the clinician extracts both the displacement differential between the injured and healthy knees, and the slope of the compliance curve (ΔP2), which captures the structural behaviour of the ACL and surrounding soft tissue.
The GNRB® is positioned with the patient supine, knee at 20° of flexion — replicating the standard Lachman test position. The device records the complete force-displacement curve at forces up to 200 N (with 300 N available), automatically comparing both sides and generating a standardised report. Testing a single knee takes approximately 10 minutes.
The GNRB® operates without accessories: no LDA Couch is required for the standard configuration. This makes it the entry point to the Genourob system — capable of rigorous ACL assessment with minimal setup.
The GNRB® platform is in use in 50+ countries. It is validated in pre-operative ACL rupture diagnosis, post-operative graft monitoring, return-to-sport decision support, and orthopaedic research comparing surgical techniques. Its data is directly comparable with the growing international GNRB® literature.
Key Advantages
Automated, Examiner-Independent Forces
The GNRB® applies precisely defined loads to the tibia without the examiner's hands on the knee during measurement — eliminating the examiner variability that limits manual arthrometers like the KT-1000 and Rolimeter. Every test is reproducible regardless of who performs it.
Force-Displacement Compliance Curves
Rather than a single displacement measurement, the GNRB® generates a complete force-displacement curve. This curve provides two clinically meaningful outputs: the total displacement differential between knees, and the ΔP2 slope, which reflects the structural stiffness of the ACL. Together they offer a richer picture of ligament integrity than a point measurement alone.
Validated Research Platform
The GNRB® has been used as the reference measurement tool in peer-reviewed studies across Europe, the Middle East, and Australia — comparing ACL reconstruction techniques, graft types, and return-to-sport criteria. Any centre adopting the GNRB® joins a growing international literature built on directly comparable data.
No Accessories Required
The standard GNRB® configuration requires no additional modules or dedicated couch — making it the most accessible entry point to automated knee laximetry. Clinics with limited space or budget can deploy the full ACL assessment capability of the Genourob platform without additional infrastructure.
Upgrade Path to Full Knee Assessment
The GNRB® is the foundation of the Genourob system. Centres requiring PCL assessment can upgrade to the GNRB® PCL configuration; centres requiring rotational assessment can add the Rotab module; and centres seeking the latest technology can transition to the DYNEELAX®, which adds ACL rotation and a fully integrated platform in a single device.
Included & Optional Accessories
- Knee Cup — standardises knee position and tightening force for both knees
- Foot Locker — secures the patient's foot for accurate testing
- Knee Locker — locks the knee at the correct angle and records tightening values
- Ruler — records device position for session-to-session comparability
Technical Specifications
| Assessment | Anterior tibial translation (ACL) |
| Method | LDA® — Laxity Displacement Analysis |
| Test Position | Supine, knee at 20° flexion (Lachman position) |
| Force Applied | Up to 200 N standard (300 N maximum) |
| Force Application | Automated — no examiner hand contact during measurement |
| Output | Force-displacement compliance curve + displacement differential (mm) + ΔP2 slope |
| Accessories Required | None — standard GNRB® operates without LDA Couch |
| Testing Time | Approximately 10 minutes per knee |
| Countries in Use | 50+ |
| Certification | CE Medical Device |
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DYNEELAX® Dynamic Knee Laximetry Arthrometer
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