Related Experiment Video
Updated: Aug 6, 2026
A Morphometric and Cellular Analysis Method for the Murine Mandibular Condyle
Published on: January 11, 2018
Histomorphometry of fragmented medial coronoid process in dogs: a comparison of affected and normal coronoid
Kelson C Danielson1, Noel Fitzpatrick, Peter Muir
1Comparative Orthopaedic Research Laboratory, University of Wisconsin, School of Veterinary Medicine, Madison, 53706, USA.
Objective:
To determine if fatigue microdamage is associated with fragmented medial coronoid process (FMCP).
Study Design:
Prospective study.
Animals:
Thirty-eight dogs were admitted for subtotal coronoid ostectomy as treatment for FMCP. Surgical specimens of medial coronoid process (MCP) were retrieved from treated dogs. Normal MCP were collected from 5 age- and breed-matched dogs and 2 age-matched research beagles that were euthanatized for reasons other than elbow disease.
Methods:
MCP specimens from affected elbows were classified into 4 groups based on disease severity. Specimens were bulk-stained for microdamage using 1% basic fuchsin, embedded in polymethylmethacrylate and sectioned at 130 microm. Specimens were evaluated using epifluorescent microscopy (425-440 excitation, 475 nm barrier filter) for diffuse damage (D.DX), osteocyte loss, and porosity. Cartilage thickness was evaluated using bright field microscopy. Qualitative observations were also made.
Results:
MCP specimens from affected elbows had increased D.Dx, increased osteocyte loss, and greater porosity than normal groups. Specimens classified as severe FMCP (Classes 3, 4) had the most fatigue microdamage. Some Class 1 specimens, defined as having no visible fissuring of the articular cartilage (AC), had large microcracks in trabecular bone.
Conclusions:
Accumulation of subchondral fatigue microdamage, is associated with MCP fragmentation. Fissuring occurs in the subchondral bone before gross fibrillation of articular cartilage develops.
Clinical Relevance:
Accumulation of fatigue microdamage in the MCP is important in the pathogenesis of FMCP. The underlying cause of this microdamage accumulation must be identified before treatment plans that will prevent further osteoarthritis of the elbow joint can be designed.
Insights
Fatigue microdamage in the medial coronoid process (MCP) is linked to fragmented medial coronoid process (FMCP) in dogs. This bone damage occurs before cartilage changes, indicating its importance in FMCP development.
Area of Science:
- Veterinary Orthopedics
- Biomechanical Engineering
- Canine Pathology
Background:
- Fragmented medial coronoid process (FMCP) is a common canine elbow disease.
- The pathogenesis of FMCP, particularly the role of fatigue microdamage, requires further elucidation.
Purpose of the Study:
- To investigate the association between fatigue microdamage and fragmented medial coronoid process (FMCP).
- To evaluate the severity of microdamage in relation to FMCP classification.
Main Methods:
- Prospective study involving 38 dogs with FMCP undergoing coronoid ostectomy.
- Analysis of medial coronoid process (MCP) specimens using bulk staining for microdamage and microscopy.
- Evaluation of diffuse damage (D.Dx), osteocyte loss, porosity, and cartilage thickness.
Main Results:
- Affected MCP specimens exhibited increased diffuse damage, osteocyte loss, and porosity compared to controls.
- Severe FMCP cases (Classes 3 and 4) showed the highest levels of fatigue microdamage.
- Microcracks were observed in subchondral bone even in early-stage FMCP (Class 1) with no visible cartilage fissuring.
Conclusions:
- Subchondral fatigue microdamage accumulation is associated with MCP fragmentation.
- Bone microdamage precedes articular cartilage fibrillation, highlighting its role in FMCP pathogenesis.
- Identifying the cause of microdamage is crucial for developing strategies to prevent elbow osteoarthritis.
