Evaluation of intra-articular collagenase, TIMP-1, and TNF-alpha levels before and after anterior cruciate ligament reconstruction.

OBJECTIVES

We investigated intra-articular levels of collagenase, which presumably promotes bone-tendon healing, and collagenase mediators involved in its production (tumor necrosis factor-alpha, TNF-alpha) and inhibition (TIMP-1 enzyme) in patients following anterior cruciate ligament (ACL) reconstruction.

METHODS

The study included 16 patients (15 males, 1 female; mean age 27 years; range 17 to 40 years) who underwent arthrocentesis due to effusion that developed following reconstruction of isolated ACL injuries. Intra-articular levels of collagenase, TNF-alpha, and TIMP-1 were measured using appropriate activity assay and immunoassay kits in synovial fluid samples obtained intraoperatively and during arthrocentesis. The mean time from ACL injury to surgical repair was 21+/-10 months (range 1 to 72 months). Arthrocentesis was performed in a mean of 18 hours (range 12 to 36 hours) following ACL repair.

RESULTS

Measurements in synovial fluid samples obtained intra- and postoperatively yielded 1.49+/-0.06 ng/ml and 1.45+/-0.05 ng/ml for collagenase, 12+/-5 ng/ml and 22+/-9.5 ng/ml for TIMP-1, and 10.4+/-7.1 pr/ml and 14.11+/-6.1 pr/ml for TNF-alpha, respectively. Postoperative changes in the levels of collagenase (p=0.098) and TNF-alpha (p=0.069) were not significant, whereas increase in the TIMP-1 level was significant (p=0.026).

CONCLUSION

This study showed elevated levels of TNF-alpha, collagenase, and TIMP-1 due to the presence of ruptured ACL. Our findings showed how these levels changed in the acute postoperative period.