FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Open veterinary journal2025; 15(8); 3787-3793; doi: 10.5455/OVJ.2025.v15.i8.43

Autologous conditioned serum IRAP efficacy for tendon and ligament injuries in horses: An observational study.

Abstract: Tendon and ligament injuries in equine athletes pose significant challenges, often leading to prolonged recovery, reduced performance, and increased risk of reinjury. Current treatment strategies, including conservative and surgical approaches, have shown limited success in fully restoring tendon integrity. Autologous blood derivatives, such as autologous conditioned serum (ACS), have emerged as potential regenerative therapies. However, the clinical efficacy of ACS in the treatment of equine tendinopathies remains under investigation. Unassigned: This study aimed to compare the clinical outcomes between intralesional ACS injections and conservative treatment in horses diagnosed with superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) injuries. Unassigned: This retrospective observational case-control study used clinical data from 100 horses evaluated for lameness between 2017 and 2022. Horses were categorized into two groups: the IRAP group ( = 48), which received three intralesional ACS injections at 1-week intervals, and the NO-IRAP group ( = 52), which was treated conservatively with NSAIDs and a structured rehabilitation program. Lameness assessments and ultrasonographic evaluations were performed at initial presentation and follow-up at 4, 8, and 12 weeks. The statistical analyses compared changes in lameness scores between the two groups. Unassigned: At 4 weeks, improvement in lameness was observed in 51.5% and 55.6% of the IRAP and NO-IRAP groups, respectively. At 8 weeks, improvement rates were 47% and 42.2%, respectively. By 12 weeks, 60.7% of the IRAP group and 55% of the NO-IRAP group showed improvement. However, a subset of horses in the IRAP group experienced transient worsening of lameness (8.5%-17.7%). Stratification by lesion type revealed better outcomes in the IRAP group for SDFT (58.3% 48%) and SL (51.2% 36%) injuries, whereas the NO-IRAP group had superior results for DDFT injuries (60.9% 46.2%). Unassigned: The study suggests that ACS treatment enhances tendon and ligament healing, particularly in SDFT and SL injuries. However, the transient worsening of lameness observed in some horses receiving ACS warrants further investigation. Although these findings support the potential benefits of ACS, controlled randomized clinical trials are needed to validate its efficacy and optimize treatment protocols for equine tendon and ligament pathologies.
Get Full Text
Publication Date: 2025-08-31 PubMed ID: 41036008PubMed Central: PMC12483392DOI: 10.5455/OVJ.2025.v15.i8.43Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article
  • Observational Study
  • Veterinary

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study evaluated the effectiveness of autologous conditioned serum (ACS), delivered via intralesional injections, compared to conservative treatment for tendon and ligament injuries in horses.
  • The research focused on equine superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) injuries, analyzing clinical outcomes from 100 cases over a 12-week period.

Background and Rationale

  • Tendon and ligament injuries are common and challenging issues in equine athletes, often causing long recovery times and diminished performance.
  • Traditional treatments include conservative care (like NSAIDs and rehabilitation) and surgical repair, but these often fail to fully restore the tendon or ligament to its original state.
  • Autologous conditioned serum (ACS), a blood derivative enriched with anti-inflammatory and regenerative factors, has been proposed as a novel treatment option to promote healing, but its clinical effectiveness is not fully established.

Study Design and Methods

  • This was a retrospective observational case-control study using clinical records from 100 horses treated between 2017 and 2022.
  • Horses were divided into two groups:
    • IRAP group (n=48): Received three ACS intralesional injections spaced one week apart.
    • NO-IRAP group (n=52): Received conservative treatment consisting of non-steroidal anti-inflammatory drugs (NSAIDs) and a structured rehabilitation protocol.
  • Lameness scoring and ultrasound evaluations were performed at baseline and then at 4, 8, and 12 weeks to monitor progress.
  • The primary outcome measure was improvement in lameness scores over time, compared between the two groups.

Results

  • At 4 weeks:
    • 51.5% of horses treated with ACS showed improvement in lameness.
    • 55.6% of horses under conservative treatment improved.
  • At 8 weeks:
    • 47% improvement rate in the ACS group.
    • 42.2% improvement in the NO-IRAP group.
  • At 12 weeks:
    • 60.7% of ACS-treated horses improved.
    • 55% of those treated conservatively improved.
  • Some horses in the ACS group experienced a temporary worsening of lameness symptoms, ranging from 8.5% to 17.7% depending on timepoints.
  • When accounting for injury type:
    • ACS treatment showed better outcomes for SDFT injuries (58.3% improved vs. 48% in controls) and suspensory ligament injuries (51.2% vs. 36%).
    • Conservative treatment was more effective for DDFT injuries (60.9% improved vs. 46.2% with ACS).

Interpretation and Implications

  • The findings suggest that ACS may enhance healing particularly for superficial digital flexor tendon and suspensory ligament injuries.
  • The greater improvement in these injuries might be due to the biological effects of ACS in reducing inflammation and promoting tissue regeneration.
  • The transient lameness worsening in some horses receiving ACS could indicate an initial inflammatory reaction or other side effects that require further study.
  • The study’s observational and retrospective design limits the strength of conclusions; randomized controlled trials are needed to confirm the benefits and refine treatment protocols.
  • Results contribute to the growing evidence supporting autologous blood products as adjunct therapies in equine tendon and ligament repair.

Conclusion

  • Autologous conditioned serum shows promise as a treatment to improve healing outcomes in certain equine tendon and ligament injuries.
  • Clinical benefits were particularly notable for SDFT and suspensory ligament lesions, while conservative treatment sometimes performed better for DDFT injuries.
  • Future prospective and randomized studies are necessary to validate these results, understand the cause of transient worsening, and optimize ACS application in veterinary sports medicine.

Cite This Article

APA
Tommasa SD, Raspe S, Farí G, Imperante A, Brehm W. (2025). Autologous conditioned serum IRAP efficacy for tendon and ligament injuries in horses: An observational study. Open Vet J, 15(8), 3787-3793. https://doi.org/10.5455/OVJ.2025.v15.i8.43

Publication

Open veterinary journal
ISSN: 2218-6050
NlmUniqueID: 101653182
Country: Libya
Language: English
Volume: 15
Issue: 8
Pages: 3787-3793

Researcher Affiliations

Tommasa, Simone Della
  • Department for Horse, University of Leipzig, Leipzig, Germany.
Raspe, Sarah
  • Department for Horse, University of Leipzig, Leipzig, Germany.
Farí, Giacomo
  • Department of Biological and Enviromental Science and Technologies (Di. Ste. B.A.), University of Salento, Lecce, Italy.
Imperante, Annarita
  • Field Veterinary Surgeon, Bari, Italy.
Brehm, Walter
  • Department for Horse, University of Leipzig, Leipzig, Germany.

MeSH Terms

  • Animals
  • Female
  • Male
  • Case-Control Studies
  • Horse Diseases / therapy
  • Horses / injuries
  • Lameness, Animal / therapy
  • Ligaments / injuries
  • Retrospective Studies
  • Serum
  • Tendon Injuries / veterinary
  • Tendon Injuries / therapy
  • Treatment Outcome

Conflict of Interest Statement

None.

References

This article includes 28 references
  1. Alzola R, Easter C, Riggs CM, Gardner DS, Freeman SL. Ultrasonographic-based predictive factors influencing successful return to racing after superficial digital flexor tendon injuries in flat racehorses: a retrospective cohort study in 469 Thoroughbred racehorses in Hong Kong. Equine Vet. J. 2018;50(5):602–608.
    pmc: PMC6099230pubmed: 29352495doi: 10.1111/evj.12810google scholar: lookup
  2. Baxter GM. Tendon and ligament injuries and disease. In: Baxter GM, editor. In Adams and Stashak’s Lameness in Horses. Chichester, FL: Wiley-Blackwell; 2012. pp. 927–938.
  3. Carvalho AM, Badial PR, Álvarez LE, Yamada AL, Borges AS, Deffune E, Hussni CA, Garcia, Alves AL. Equine tendonitis therapy using mesenchymal stem cells and platelet concentrate: a randomized controlled trial. Stem Cell Res. Ther. 2013;4:85.
    pmc: PMC3854756pubmed: 23876512
  4. Dahlgren LA, Harvey SC. Effect of autologous conditioned serum on the metabolism of normal tendon explants. In: 54th Annual Meeting of the Orthopedic Research Society; March 2–5, 2019. Rosemont, IL: Orthopedic Research Society; 2008.
  5. Dahlgren LA, van der Meulen MC, Bertram JE, Starrak GS, Nixon AJ. Insulin-like growth factor-I improves cellular and molecular aspects of healing in a collagenase-induced model of flexor tendinitis. J. Orthop. Res. 2002;20:910–919.
    pubmed: 12382953
  6. Dakin SG, Dudhia J, Smith RKW. Modulation of prostaglandin E2 production in equine tendon cells. In: 49th British Equine Veterinary Association Congress; September 8–11. Newmarket, England: Equine Veterinary Journal, Ltd; 2010. p. 96.
  7. Della Tommasa S, Brehm W, Farì G, Bernetti A, Imperante A. Use of autologous conditioned serum (ACS) for osteoarthritis treatment in horses: a systematic review of clinical data. Vet. Sci. 2023;10(12):707.
    pmc: PMC10747612pubmed: 38133258doi: 10.3390/vetsci10120707google scholar: lookup
  8. Dyson SJ. Medical management of superficial digital flexor tendonitis: a comparative study of 219 horses (1992-2000). Equine Vet J. 2004;36:415–419.
    pubmed: 15253082doi: 10.2746/0425164044868422google scholar: lookup
  9. Frisbie DD, Kawcak CE, Werpy NM, Park RD, McIlwraith CW. Clinical, biochemical, and histologic effects of intraarticular administration of autologous conditioned serum in horses with experimentally induced osteoarthritis. Am. J. Vet. Res. 2007;68:290–6.
    pubmed: 17331019
  10. Hraha TH, Doremus KM, McIlwraith CW, Frisbie DD. Autologous conditioned serum: the comparative cytokine profiles of two commercial methods (IRAP and IRAP II) using equine blood. Equine Vet. J. 2011;43(5):516–521.
    pubmed: 21496084doi: 10.1111/j.2042-3306.2010.00321.xgoogle scholar: lookup
  11. Ionita JC, Brehm W. Autologe Blutprodukte in der Regenerativen Therapie: ACS, PRP, ACP, Knochenmark (Autologous blood products for regenerative therapies: ACS, PRP, ACP, bone marrow). In: Lauk HD, editor. In Pferdeheilkunde Forum-Berliner Fortbildungstage. Berlin, Germany: Hippiatrika Verlag; 2008. pp. 588–591.
  12. James R, Kesturu G, Balian G, Chhabra AB. Tendon: biology, biomechanics, repair, growth factors, and evolving treatment options. J. Hand Surg. Am. 2008;33:102–112.
    pubmed: 18261674doi: 10.1016/j.jhsa.2007.09.007google scholar: lookup
  13. Jann H, Stashak TS. Tendon and Paratendon Lacerations. In: Stashak TS, Theoret CL, editors. In Equine wound management. Ames, Iowa: Wiley-Blackwell; 2008. pp. 489–508.
  14. Lam KH, Parkin TDH, Riggs CM, Morgan KL. Descriptive analysis of the retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992-2004). Equine Vet. J. 2007;39:143–148.
    pubmed: 17378443doi: 10.2746/042516407x159132google scholar: lookup
  15. Maffulli N, Kader D. Tendinopathy of tendo achillis. J. Bone Jt Surg-Ser B. 2002;84:1–8.
    pubmed: 11837811doi: 10.1302/0301-620x.84b1.0840001google scholar: lookup
  16. Majewski M, Ochsner PE, Liu F, Fluckiger R, Evans CH. Accelerated healing of the Achilles tendon in response to autologous conditioned serum. Am. J. Sports Med. 2009;37:2117–2125.
    pubmed: 19875360
  17. Molloy T, Wang Y, Murrell G. The roles of growth factors in tendon and ligament healing. Sports Med. 2003;33:381–394.
    pubmed: 12696985
  18. Murray RC, Dyson SJ, Tranquille C, Adams V. Association between sport type and performance level and anatomical site of orthopedic injury diagnosis. Equine Vet. J. 2006;36:411–416.
    pubmed: 17402457doi: 10.1111/j.2042-3306.2006.tb05578.xgoogle scholar: lookup
  19. O’meara B, Bladon B, Parkin TDH, Fraser B, Lischer CJ. Investigation of the relationship between race performance and superficial digital flexor tendonitis in the Thoroughbred racehorse. Equine Vet. J. 2010;42:322–6.
    pubmed: 20525050doi: 10.1111/j.2042-3306.2009.00021.xgoogle scholar: lookup
  20. Patterson-Kane JC, Firth EC. Pathobiology of exercise-induced superficial digital flexor tendon injury in Thoroughbred racehorses. Vet. J. 2009;181:79–89.
    pubmed: 18406184
  21. Shojaee A, Parham A. Strategies of tenogenic differentiation of equine stem cells for tendon repair: current status and challenges. Stem. Cell Res. Ther. 2019;10(1):181.
    pmc: PMC6582602pubmed: 31215490doi: 10.1186/s13287-019-1291-0google scholar: lookup
  22. Smith RK, Werling NJ, Dakin SG, Alam R, Goodship AE, Dudhia J. Beneficial effects of autologous bone marrow-derived mesenchymal stem cells in naturally occurring tendinopathy. PLoS One 2013;8:e75697.
    pmc: PMC3783421pubmed: 24086616
  23. Smith RK. Treatment of tendinopathies. Equine Vet. Educ. 2024;36(12):659–672.
    doi: 10.1111/eve.13987google scholar: lookup
  24. Spaas JH, Guest DJ, Van de Walle GR. Tendon regeneration in human and equine athletes. Sport Med. 2012;42:871–90.
    pubmed: 22963225doi: 10.1007/bf03262300google scholar: lookup
  25. Sun HB, Li Y, Fung DT, Majeska RJ, Schaffler MB, Flatow EL. Coordinate regulation of IL-1beta and MMP-13 in rat tendons following subculture fatigue damage. Clin. Orthop. Relat. Res. 2008;466:1555–1561.
    pmc: PMC2505236pubmed: 18470577
  26. Textor J. Autologous biologic treatment of equine musculoskeletal injuries: a platelet-rich plasma and IL-1 receptor antagonist protein. Vet. Clin. North Am. Equine Pract. 2011;27:275–298.
    pubmed: 21872759
  27. Thorpe CT, Clegg PD, Birch HL. A review of tendon injury: why is the equine superficial digital flexor tendon most at risk?. Equine Vet. J. 2010;42:174–180.
    pubmed: 20156256doi: 10.2746/042516409x480395google scholar: lookup
  28. Weinberger T. Regenerative therapiemöglichkeiten beim Pferd-eine Übersicht (Regenerative treatment options in horses-an overview). Pferde Spiegel 2008;11:116–119.

Citations

This article has been cited 0 times.
Subscribe to our newsletter
Join 99,970 horse owners like you who receive our email updates on horse health and nutrition.