Table 1.

Criteria, scores, and observations for histological assessment of anterior and posterior menisci. The range of possible total score is 0–25.

Criteria	Score	Anterior	Posterior
Tissue Surface Structure
Femoral and tibial side, inner rim	0	Smooth	Smooth
	1	Slight fibrillation or undulating	Slight fibrillation or undulating
	2	Moderate fibrillation or undulating	Moderate fibrillation or undulating
	3	Severe fibrillation or undulating, - Disruption or total loss of tissue	Severe fibrillation or undulating, - Disruption or total loss of tissue
Cellularity
Outer region	0	Normal distribution of fusiform cells	Normal distribution of fusiform cells
	1	Hypercellularity	Hypercellularity
	2	Diffused hypocellularity - Few empty lacuna	Diffused hypocellularity - Few empty lacuna
	3	Hypocellularity - Empty lacuna, cyst, matrix separation	Hypocellularity - Empty lacuna, cyst, matrix separation
Inner region	0	Normal distribution of round cells	Normal distribution of round cells
	1	Hypercellularity	Hypercellularity
	2	Diffused hypo/acellular zones	Diffused hypo/acellular zones
	3	Hypocellularity - Empty lacuna, cyst	Hypocellularity
Superficial zone	0	Normal distribution of round cells	---
	1	Hypercellularity - Cell clustering	---
	2	Diffused hypo/acellularity - Cell shrinkage	---
	3	Hypocellularity	---
Matrix Staining
Outer region	0	Normal - slight staining of PCM	Normal - slight staining of PCM
	1	Slightly disrupted	Slightly disrupted
	2	Moderately disrupted	Moderately disrupted
	3	Severely disrupted	Severely disrupted
Inner region	0	---	Normal - slight staining of ECM
	1	---	Slightly disrupted
	2	---	Moderately disrupted
	3	---	Severely disrupted
Superficial zone	0	Normal - homogenous staining of ECM	---
	1	Slightly disrupted	---
	2	Moderately disrupted	---
	3	Severely disrupted	---

Bone formation: present +, ++, +++

Inflammation: present +, ++, +++