Capsular Shrinkage in the Treatment of Wrist Instability

CHAPTER 15 Capsular Shrinkage in the Treatment of Wrist Instability






Basic Science


What is old is new again. Capsular shrinkage was used by Hippocrates 2,400 years ago to stabilize dislocated shoulders. Luckily, anesthetic techniques and thermal delivery methods have improved during the past two millennia. Recently (comparatively speaking), the biology of capsular shrinkage has been extensively studied in animal models. These studies have shown that the triple helix of collagen “unwinds” and “shrinks” when heated to 60° C, maximum shrinkage being achieved between 65 and 75° C (Figures 15.1 and 15.2). The hydrogen bonds that maintain the 3D configuration of the type I collagen triple–helix rupture as the collagen is heated beyond 60° C. The denatured collagen can potentially shorten to 50% of the resting length of the untreated collagen. The shortened denatured collagen acts as scaffolding onto which new collagen is deposited.1 The new collagen fibers maintain this shortened conformation, thus assuring the long–term maintenance of the shortening.




Biomechanical studies have demonstrated that the tensile strength of heated collagen decreases rapidly and does not return to normal values for 12 weeks.2 The tensile strength returns to nearly 80% normal by six weeks after heating (Figure 15.3). This transient loss of tensile strength would suggest that the application of stress to recently heated collagen is contraindicated. Premature loading of the shrunk collagen will lead to a lengthening of the collagen. This has been verified in an animal model.3,4 Based on this data, it would seem reasonable to recommend at least six to eight weeks of joint immobilization after capsular shrinkage. Clearly heavy loading of the joint should be avoided for 12 weeks.




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Jun 22, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Capsular Shrinkage in the Treatment of Wrist Instability

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