Reconstruction of cortical bone
using coral


We have just seen the reconstruction of spongy bone at the ends of a long bone, using natural coral. Now let's see how to rebuild the wall (cortical bone) of a long bone.

Here's an example of a young man, 20 years old, who was injured in a road accident (long-term follow-up for 10 years).


Patient's clinical history:

After many problems, he saw the doctor about the delay in consolidation of his femur. He had two metal devices (external fixators), one in front and one on the side of the thigh. The knee was locked and stiff in extension. The thigh bone (femur) was not strong. There were several centimetres missing between the two ends. The ends were stripped and white. In short, this bone had to be consolidated by the insertion of material. The classic technique consists of taking a fragment of the patient's bone from the pelvis (a graft) and inserting it so that it fills the void and consolidates the bone.

This excellent technique is tried and tested and practised by most traumatologists. If we can accept the idea that a biomaterial behaves like an immunologically compatible bone graft, it should be possible to obtain the same result but with a distinct advantage. We are not obliged to take a bone graft. We don't have to perform another operation which is always painful.

The coral implantation was performed. The coral spheres on all four sides of the bone wall were counted.

Counting spheres

  Spheres Feb
1993		 Mar
1993 		Sept
1993 		Dec
1993 		June
1994 		May
1995 		Apr
1996		 Apr
1997 		May
1998 		May
1999 		Dec
1999 		Feb
2002
Medium   111 89 52 57 38 34 22 20 24 13 7 0
Lateral   68 55 21 19 - - - - - 7 9 0
Anterior   79 57 - - - - 6 9 - - 15 10
Posterior   100 74 50 52 47 - 32 39 21 29 24 15

A parallel was established between the disappearance of the spheres and the formation of the bony callus.

Compared evolution of callus development and disappearance of the coral

DATE BONY CALLUS NATURAL CORAL
PARTIAL UNITING RODS SPHERES
  A. P. I. E. A. P. I. E. Visibles Resorbed Visibles Resorbed
DECORTICATION + Coral GRAFT (50% porosity)
25-02-93 0 0 0 0         ++++   ++++  
25-03-93   + +     + +   ++++   ++++  
20-04-93   + +     ++ ++   ++++   ++++  
ABLATION OF FIXATOR + PLATE
10-05-93   ++ ++     ++ ++ + ++++   +++ +
10-09-93 +       + +++ +++   +++ + ++ ++
13-12-93 ++       + +++ ++++   ++ ++ + +++
14-06-94 ++       + ++++ ++++   ++ ++ + +++
03-04-95 ++       + ++++ ++++   ++ ++ + +++
11-05-96 ++       ++ ++++ ++++   ++ ++ + +++
29-04-97 ++       ++ ++++ ++++   ++ ++ + +++
11-05-98 ++       ++ ++++ ++++   ++ ++ + +++
ABLATION OF THE PLATE
11-12-99 ++       ++ ++++ ++++ ++++ ++ ++ + +++
29-01-02 +++       +++ ++++ ++++ ++++ ++ ++ 15% 85%

Visual scale : + = 25% ; ++ = 50% ; +++ = 75 % ; ++++ = 100%
Walls : A=Anterior ; P=Posterior ; E=External ; I=Internal

A complete and gradual reconstruction of the femoral walls (container) took place. Reconstruction involved five phases (numbered in Roman numerals).

I: FIRST BIORESORBABILITY
- It occurs centrifugally with disappearance of the central spheres.
- Resorption is quantitative. The peripheral spheres remain visible.
- It is rapid, taking place in two to three months (spheres).
- The layout, dispersion and distribution of the spheres is random.

II: ALIGNMENT IN A COLUMNAR RIDGE
- The spheres were aligned vertically, parallel to the main diaphyseal axis.
- Alignment occurred over six to nine months (spheres).
- Sphere dispersion remains random.

II: REDUCING THE DIAMETER OF THE COLUMNS
- The diameter of the columns is reduced by medullary resorbability.
- A concentration of spheres was noted along the main axis of the diaphyseal wall. It took place in centrifugal fashion.
- This arrangement took place between twelve and eighteen months (spheres).

III: REMODELLING THE COLUMNAR RIDGE
- The spheres were in a longitudinal architectural structure, aligning in fine columns along the main parietal axis, one above the other.
- Reduction in width of the column

IV: SECOND RESORBABILITY
- Reduction in sphere diameter, producing the cortical bone which becomes punctiform.
- The second resorption occurs in twelve months on average (spheres).
- Production of Haversian type cortical bone occurs at the same time.

V: CORTICALISATION AND CORTICAL THICKENING
- Homogeneous reconstruction of the periosteal cortex precedes that of the endomedullary cortex.
- This occurs a few weeks later and is complete in one year.
- The wall under compression thickens and becomes homogeneous.
- The thickening is complete in one year.

X-rays copies on tracing paper shows the progress of reconstruction of the wall – the container.


We trace the logarithmic curves of the coral disappearance.

A magnificent femoral diaphysis (part of the femur between hip and knee) is reconstructed before your eyes.

The result relative to knee stability and mobility is clear (mobility: 0-105°).

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