Mankin, J Bone Joint Surg Am 1971 - Biochemical and Metabolic Abnormalities in Articular Cartilage from Osteo-Arthritic Human Hips. II. Correlation of Morphology with Biochemical and Metabolic Data - Article Summary

Biochemical and Metabolic Abnormalities in Articular Cartilage from Osteo-Arthritic Human Hips. II. Correlation of Morphology with Biochemical and Metabolic Data

Mankin, Zarins, et al.·J Bone Joint Surg Am·1971·803 citations·Basic science

Mankin et al. analyzed 32 discrete cartilage sites from 9 osteoarthritic and 4 normal human femoral heads, correlating a newly devised histologic-histochemical grading system (scoring structure, cellularity, safranin-O staining, and tidemark integrity) with biochemical measures of cell density (DNA), polysaccharide content (hexosamine), DNA synthesis (³H-thymidine incorporation), and proteoglycan synthesis (³⁵SO₄ incorporation) to define how cartilage biology changes across the spectrum of OA severity.

Key Findings

A four-domain grading system was introduced scoring each histologic feature separately, for a total of 0–14 (observed scores in this study ranged 1–13):
- Structure: 0–6
- Cell distribution: 0–3
- Safranin-O staining: 0–4
- Tidemark integrity: 0–1
Proteoglycan (hexosamine) content fell inversely with grade (index of determination = 0.49), while ³⁵SO₄ incorporation rose with severity up to grade 10 (index of determination = 0.88) — cartilage mounts increasing synthetic effort that still cannot keep pace with catabolism
Both DNA synthesis and proteoglycan synthesis increased with disease severity up to grade 10, above which an apparent metabolic 'fall-off' occurred (too few points for statistical analysis); the authors suggested a point of irreversibility beyond which reparative mechanisms fail
DNA concentration did not correlate with disease grade, implying total cell number stays roughly constant because increased replication compensates for increased cell death — the tissue maintains cellularity even as it structurally deteriorates
Osteophyte cartilage was less severely graded (−15.7%), contained more hexosamine (+20.2%), and showed higher sulfate incorporation (+28%) than adjacent non-osteophytic arthritic cartilage, without a corresponding rise in DNA synthesis — the authors read this as against osteophyte cartilage being newly formed reactive cartilage, suggesting the underlying bone grows while the cartilage only remodels its matrix

Supplemental

Biochemical and Metabolic Abnormalities in Articular Cartilage from Osteo-Arthritic Human Hips. II. Correlation of Morphology with Biochemical and Metabolic Data.

Mankin, Zarins, et al.J Bone Joint Surg Am1971803 citationsBasic science