Homeostasis restored

Rationale for hyaluronan as a synovial fluid replacement

Once the synovial fluid is flushed out of the joint, the balance of the articular environment is lost. Replacement of the synovial fluid with hyaluronan may promote restoration of homeostasis inside the joint.

Restoring the articular homeostasis

Studies have shown that exogenous hyaluronan:

• restores cartilage metabolism following the physiological disturbance caused by irrigating solution^15,16
  
  
• protects the articular cartilage and synovial membrane from damage through its functional and structural properties^17-25
  
  
• suppresses chondrolysis of cartilage by reducing penetration of fibronectin fragments⁴
  
  
• restores cartilage glycosaminoglycan content following 6 weeks of joint immobilisation; in addition, treatment with remobilisation and hyaluronan increased glycosaminoglycan content more than remobilisation alone²⁶
  
  
• promotes repair of degraded cartilage, reverses the damage caused by exposure to fibronectin or interleukin-1, and restores proteoglycan to normal levels²⁷
  
  
• promotes meniscal regeneration following meniscectomy and appears to inhibit degeneration of articular cartilage for up to 6 months^28,29
  
  
• stimulates collagen remodelling and inhibits swelling during healing of meniscal tears in a rabbit model of total medial meniscectomy³⁰
  
  
• stimulates the synthesis of endogenous hyaluronan³¹
  
  
• promotes wound healing³² and the healing response following surgical laceration of the anterior cruciate ligament in rabbit models.³³
  
  

Saline irrigation significantly inhibits cartilage metabolism, as shown by reduced 35S-sulphate incorporation into proteoglycans.
It is restored to normal by the addition of hyaluronan¹⁶

Following partial meniscectomy, hyaluronan promotes meniscal regeneration compared with saline²⁹

Exogenous hyaluronan stimulates healing of damage to the
anterior cruciate ligament (ACL)³³