Fig. 1 — One ligament, three states: stretch, partial tear, complete tear.
What the grades describe
Soft-tissue injuries are graded I through III on the state of the tissue, following the American Academy of Orthopaedic Surgeons definitions:
- Grade I — mild: the ligament, muscle, or tendon is stretched beyond its resting length but remains intact. Pain and mild swelling; function largely preserved.
- Grade II — moderate: a partial tear. More pain, more swelling, some loss of strength or range of motion.
- Grade III — severe: a complete tear or rupture. The structure is severed; the joint it stabilized may feel loose, and function is lost until it heals or is repaired.
The same three-part logic appears across the medical literature — MedlinePlus describes the grades the same way for sprains and strains generally, and the Quebec Task Force's WAD I/II/III ladder applies the same escalating pattern to whiplash specifically (see the whiplash file).
How a grade is assigned
A grade is a clinical finding, made from the exam — tenderness, swelling, range of motion, joint stability — and confirmed or refined by imaging where it is ordered. It is not a pain score. The imaging file explains what each modality contributes to the picture.
What a grade means for the record
For the documentation that follows an injury, the grade does three jobs:
- It anchors severity — a "grade II" recorded on day three tells a later reader the tissue state at the time, even if the notes are brief.
- It frames the expected course — the grade is the main input to the ranges in the recovery file.
- It is a consistency check — the grade, the exam findings, and the imaging should tell the same story. Where they diverge, the record explains why.
Grading is not prognosis. A grade describes tissue, not outcome. Some Grade I injuries linger and some Grade II injuries resolve quickly — which is exactly why the record keeps being written after the first visit.