Abstract
Introduction
Post-arthroscopic glenohumeral chondrolysis (PAGCL) is a rare, but significant, complication of arthroscopic shoulder surgery that may lead to arthroplasty. Exact causal factors and pathways associated with the development of PAGCL are unknown however a number of patient factors and surgical factors have been implicated. Suture is one of these potential causal factors and currently little is known about the body's immune response to commonly used orthopaedic sutures. The aim of this project is to examine the biological response to 3 commonly used orthopaedic sutures (Ethibond, Fibrewire, and Orthocord) in a murine airpouch model. It was hypothesised that different sutures would elicit a different histological response and that suture wear-debris would induce an increased inflammatory reaction compared to intact suture.
Methods
Total of 50 male Wister rats (12 weeks old) were used in this study. 5 rats were used per time point per group. Rat air-pouch was created according to a protocol previously described by Sedgewick et al. (1983). Once the pouch was established, on day 6, an incision was made and one of the test materials (intact Ethibond, intact Orthocord, intact Fibrewire, Fibrewire wear-debris) administered. Following wound closure, 5 ml of sterile PBS was injected to suspend the implanted materials. Negative control animals were injected with PBS alone. Rats were sacrificed at 1 and 4 weeks following surgery. The entire pouch was harvested and processed for H&E histology. The images of histological stained sections were digitally photographed and evaluated for presence of synovium and inflammatory reaction. Foreign body giant cells were quantified by two independent, blinded observers.
Results
All animals recovered well and no infection were seen in any specimen. Synovium environment was confirmed by the presence of synovium lining in the airpouch (Figure 1). Giant multinucleated cells were confirmed to populate the suture material in all treatment groups (Figure 2) at both time points but not in the control specimens. Cell count results are summarized in Figure 3. Briefly, no statistical difference was found in the number of cells counted between intact suture groups at either time point. The number of cells increased in all groups from 1 week to 4 weeks however the difference was not found to be statistically different. Significant difference was found between Fibrewire intact suture and Fibrewire suture wear debris at both 1 and 4 week time points (p = 0.032 and 0.047 respectively).
Discussion
No differences were observed between the biological reactivity of commonly used orthopaedic sutures. When particles (suture wear-debris) were implanted they elicited a greater inflammatory response then intact suture alone. This was confirmed by increased number of foreign body cells quantified. Increased inflammatory response may lead to PGAL and ultimately arthroplasty.
