Synovial response to intra-articular metal debris: Implications for anterior cruciate ligament reconstruction

Abstract

Purpose: Intra-articular metal debris is occasionally seen after completion of an endoscopic anterior cruciate ligament reconstruction. The purpose of this study was to examine the tissue response to intra-articular stainless steel metal debris in order to better understand its role in the inflammatory process.

Type of study: Animal case control study.

Methods: Metal filings created from a Beath pin were injected into 10 rabbit knees. The opposite knee of each rabbit was used as a control. The animals were killed at 4 weeks. The knee joints were fixed, sectioned, stained, and examined under light microscopy.

Results: Mild to moderate levels of synovial proliferation were observed in all knees injected with metal particles. There was no evidence of phagocytosis of the metal particles, nor was there any evidence of an inflammatory response. No articular cartilage damage was observed as a result of the metal debris.

Conclusions: We believe that the few particles of stainless steel that may be produced during the reaming process in anterior cruciate ligament reconstruction do not pose a significant risk of inciting an inflammatory reaction or cause articular cartilage damage within the knee joint.