Review of literature - Repair Pins

Introduction

Until today, adequate therapy of cartilage defects (particularly in case of advanced cartilage defects) still presents a huge problem for both physicians and patients (12, 13).

In 1743, Hunter already found out that damaged cartilage is not repairable (18). A thorough scientific analysis the structure and neogenesis significantly contributed to a better understanding of cartilage (19, 23).

Function and strength of human cartilage are directly related to its intact structure. The specific structure of hyaline joint cartilage ensures its damping and sliding function and thus mobility of the joint.

Cartilage is neither vascularised nor innervated. Due to its limited regeneration and healing ability there are still significant therapeutic problems. Only in case of simultaneous damage of the subchondral bone lamella fibrocartilaginous replacement tissue is formed. Although this tissue does not have the same mechanical properties as hyaline cartilage, it can successfully replace some functions of hyaline cartilage.

For decades, numerous attempts have been made to regenerate destroyed cartilage (11, 20, 22, 26).

So far, only pain relief can be achieved by means of medication and successful cartilage regenerating measures are not yet available for patients.

At present, some 5 million people suffer from arthrosis symptoms in Germany (14). Due to the demographic development, the frequency of arthrosis as well as the resulting frequency of surgical interventions will further increase. At present, more than 50,000 knee endoprostheses are implanted in Germany every year, with increasing tendency (10). The demand for new, more effective and more cost-effective surgical methods is also driven by the limited resources in the healthcare system.

Besides axis-correcting techniques, arthroscopic techniques are mainly used in the treatment of arthrosis (13). By means of debridement and arthroscopic rinsing as well as removal of structurally changed cartilage the associated inflammation is reduced and temporary relief achieved in most cases. However, duration of the pain relief varies from several years to only a few months (14). Common arthroscopic techniques, such as Pridie drilling, abrasion arthroplasty as well as microfracturing are based on the established principle of marrow-stimulating techniques.

Fibrocartilaginous replacement tissue is induced when pluripotent stem cells reach the bone surface and biological resurfacing is finally achieved (23, 26).

Cartilage growth is thus achieved by means of penetration of blood vessels in the subchondral bone lamellae with subsequent bleeding and scaring (21).

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