Evaluation of the concentration and molecular weight of hyaluronic acid in synovial fluid before and after arthroscopic irrigation in horses with intra-articular osteochondral fragmentation

Introduction

Joint irrigation fluids replace synovial fluid (SF) during arthroscopy. It is known that only after 24 hours hyaluronic acid (HA) concentrations return to baseline levels. However, we have poor information of the immediate effects of arthroscopy on SF replacement. Therefore, the objective of the study was to evaluate the concentration and molecular weight of HA in the SF of horses in the first hour after arthroscopy.

Materials and methods

Horses with osteochondral fragmentation undergoing arthroscopy of two or more joints were included. A prospective study of the first joints accessed was carried out. Arthroscopy was performed with irrigation of lactated Ringer’s solution and SF was collected from the same joint at the beginning of the first procedure and at the end of the last arthroscopy (average ± standard deviation of 61 ± 23 minutes). HA was identified by agarose gel electrophoresis and its concentration and molecular weight were quantified by densitometry. The HA concentration was corrected by the urea concentration. Data were evaluated using the paired T and Wilcoxon test (Jamovi 2.3).

Results

Concentration (baseline: 0.97 ± 0.36 mgHA/mgU; post-arthroscopy: 0.61 - 0.36 mgHA/mgU; p<0.001; d=1.16) and weight (baseline: 7,767 ± 987 kDa; post-arthroscopy: 4,134 ± 596 kDa; p<0.001; d=1) of the HA of the SF after arthroscopy was significantly lower, despite being present and measurable.

Discussion/conclusions

In the first hour after arthroscopy, despite being significantly lower, the SF presents levels greater than 50% in the concentration and molecular weight of HA, compared to baseline values. The study therefore demonstrates a process of early reestablishment of HA production in SF after arthroscopic irrigation, providing protection to the joint surface in the immediate postoperative period, even during anesthetic recovery