Successful Management of Tendinopathy With Injections of the MMP-inhibitor Aprotinin

Abstract

Aprotinin is a broad spectrum proteinase inhibitor (including matrix metalloproteinase [MMP] inhibitor) used for treating patellar and Achilles tendinopathies. One previous randomized control trial demonstrated aprotinin injections superior to both corticosteroid and saline injections in patellar tendinopathy (Level II), whereas results reported for aprotinin treatment in Achilles tendinopathy have been mixed. We performed a case review and followup questionnaire for 430 consecutive patients with tendinopathy treated by 997 aprotinin injections (30,000 KIU). A response rate of 72% was achieved with a minimum followup of 3 months (average, 12.2 months; range, 3-54 months). Seventy-six percent of patients had improved, 22% of patients reported no change, and 2% were worse. Sixty-four percent of patients thought aprotinin injections were helpful, while 36% believed they had neither a positive nor negative effect. Mid-Achilles tendinopathy patients (84% improvement) were more successfully treated than patellar tendinopathy patients (69% improvement). Despite stronger published evidence of benefit in patellar tendinopathy, clinical outcomes appeared better with aprotinin use in Achilles tendinopathies.

Metalloproteases and rotator cuff disease

“…81,97 Although enzyme inhibitors have not been extensively evaluated in the treatment of tendinopathy, 2 small trials have ascertained whether patients with patellar and Achilles tendinopathy may benefit after peritendinous injections of aprotinin, a general protease inhibitor, 74 but further evidence of its efficacy has been shown in a large case series on chronic tendinopathy. 86 In a small, randomized trial of patients with Achilles tendinopathy, combined treatment with aprotinin and eccentric exercises did not significantly improve outcomes compared with placebo, although results in both groups were satisfactory. 17 Despite the theoretic benefits and this low level of evidence, aprotinin is no longer available in most countries to use as an injectable MMP inhibitor (in small doses).…”

Relative contributions of mechanical degradation, enzymatic degradation, and repair of the extracellular matrix on the response of tendons when subjected to under‐ and over‐ mechanical stimulations in vitro

“…Aprotinin, a broad spectrum serine protease inhibitor, has been used successfully in the management of tendinopathy. 21 It has indeed been observed that some proteases may be essential in healthy tendons, as well as tendons undergoing repair. 22 The test platform that we developed could be used to help differentiate which proteases should be inhibited.…”

Radiological interventions for soft tissue injuries in sport

“…MMP inhibitors such as aprotinin may control the cycle of degradation and repair. There are conflicting reports of the efficacy of peritendonous injection of aprotinin in treatment of patellar and Achilles tendonopathy [28]. A randomised controlled trial (RCT) of Achilles tendonopathy did not show any significant improvement in outcome for patients treated with aprotonin vs placebo [29].…”