View Full Version : Re: "Cracking Joints" - review article

Charles E. (ted) Wright
04-03-1997, 10:18 AM
On Thu, 3 Apr 1997, Greg Kawchuk wrote:

> David,
> This article is an excellent review of this topic:
> The audible release associated with joint manipulation.
> Jmpt (Journal of Manipulative & Physiological Therapeutics).
> 18(3):155-64, 1995 Mar-Apr. (40 ref)
> __________________________________________________ __________________
> Greg Kawchuk D.C., M.Sc.
> Clinician, University Health Services
> Ph.D. Student, McCaig Centre for Joint Injury and Arthritis Research

I thought that others might like to know the punch line.

Ted Wright

1. Brodeur R.
The audible release associated with joint manipulation.
Journal of Manipulative and Physiological Therapeutics, 1995 Mar-Apr,

Abstract: OBJECTIVE: The objective of this paper is to review the literature on
the audible release associated with manipulation. DATA SOURCES:
Bibliographic information in pertinent articles and papers located in the
MEDLINE database containing the keywords joint, joints, cartilage, crack,
cracking, cavitation, crepitus and noise. STUDY SELECTION: All articles
relevant to the objectives were selected. DATA EXTRACTION: All available
data was used. DATA SYNTHESIS: The audible release is caused by a
cavitation process whereby a sudden decrease in intracapsular pressure
causes dissolved gasses in the synovial fluid to be released into the joint
cavity. Once a joint undergoes cavitation, the force-displacement curve
changes and the range of motion of the joint increases. The gasses released
from the synovial fluid make up about 15% of the joint volume and consist
of approximately 80% carbon dioxide. Habitual joint cracking does not
correlate with arthritic changes, but does correlate with loss of grip
strength and soft-tissue swelling. During the "crack" associated with a
joint manipulation, there is a sudden joint distraction that occurs in less
time than that required to complete the stretch reflexes of periarticular
muscles. Theories on the cavitation mechanism were reviewed and new
information on the cavitation process is introduced. In this paper, it is
proposed that the cavitation process is generated by an elastic recoil of
the synovial capsule as it "snaps back" from the capsule/synovial fluid
interface. CONCLUSIONS: Because the sudden joint distraction during a
manipulation occurs in a shorter time period than that required to complete
the stretch reflexes of the periarticular muscles, there is likely to be a
high impulse acting on the ligaments and muscles associated with the joint.
This is an important conclusion, because others have proposed that reflex
actions from high threshold periarticular receptors are associated with the
many beneficial results of manipulation. This suggests that the cavitation
process provides a simple means for initiating the reflex actions and that
without the cavitation process, it would be difficult to generate the
forces in the appropriate tissue without causing muscular damage.