# PATHOMECHANICS OF FEMORAL HEAD ASEPTIC NECROSIS

> **NIH NIH R01** · UNIVERSITY OF IOWA · 1989 · $106,096

## Abstract

Aseptic necrosis of the femoral head is an often-disabling disease
entity which can result from any of several forms of circulatory
compromise to tenuously perfused weight-bearing bone.
Preservation of the natural femoral head is an important goal,
particularly in the younger adult patients for whom prosthesis
loosening would be a strong likelihood.  Presently, it is difficult to
predict which infarcted femoral heads will suffer early or late
collapse, and the relationship between involvement region and
severity of symptoms is not well understood.  We hypothesize,
based on preliminary studies and data in the literature, that
femoral heads with osteonecrosis of varying configurations not
only have varying potential for collapse, but that collapse can be
reliably predicted by appropriate mechanical models.

Osteonecrosis generally involves structural comprise of affected
bony regions due to the fact that the complex natural repair
processes which accompany infarct revascularization tend to
result in net resorption of necrotic trabeculae, prior to eventual
trabecular reconstitution with newly deposited viable bone.  We
propose to use finite element analysis to study several aspects of
the structural behavior of the weakened necrotic femoral head.  A
fully anatomic three-dimensional linearly elastic model is
proposed (Specific Aim I) to estimate the stress aberrations
associated with five general configurations of infarct
development, and to estimate the mechanical consequences of
core-drilling, bone grafting, and varus/derotation osteotomy for
each of these infarct configurations.  We propose also to exercise
to three-dimensional elastic model for individual infarct
configurations (Specific Aim II) detected in five specific patients
using magnetic resonance imaging.  To more closely explore the
mechanisms of actual structural failure in the necrotic femoral
head (Specific Aim III), we propose to build upon preliminary work
a linear elastic fracture mechanics finite element algorithm that
has proven capable of predicting crack propagation patterns
similar to those seen clinically.

Although the biomechanical aspects of osteonecrosis are presently
not well understood, most current therapeutic measures are
essentially mechanical in nature.  The significance of the
proposed work lies in helping better delineate the indications for
surgical intervention, and in helping to more selectively identify
which procedure is likely to be of greatest benefit for specific
head involvement patterns.

## Key facts

- **NIH application ID:** 3157359
- **Project number:** 5R01AR035788-02
- **Recipient organization:** UNIVERSITY OF IOWA
- **SAM.gov UEI:** Z1H9VJS8NG16
- **Principal Investigator:** THOMAS DUDLEY BROWN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $106,096
- **Award type:** 5
- **Project period:** 1988-03-01 → 1991-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3157359

## Citation

> US National Institutes of Health, RePORTER application 3157359, PATHOMECHANICS OF FEMORAL HEAD ASEPTIC NECROSIS (5R01AR035788-02). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3157359. Licensed CC0.

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