Polymer-hydroxyapatite composite versus polymer interference screws in anterior cruciate ligament reconstruction in a large animal model

  • John A. Hunt
  • Jill T. Callaghan


The aim of the study was to assess the hard tissue response of a composite hydroxyapatite/poly l-lactic acid (HA/PLLA) interference screw for anterior cruciate ligament (ACL) reconstruction compared to a standard PLLA screw. Twelve skeletally mature rams underwent unilateral ACL reconstruction using an autologous bone-patellar tendon graft. Each animal received either two test HA/PLLA interference screws or two control PLLA interference screws. Animals were sacrificed at 6 and 12 months post-implantation and the operated knees excised. Undecalcified sections of the screw and surrounding tissues were cut from resin embedded samples and stained; sections were approximately parallel to the longitudinal axis of the screws. A quantitative assessment of bone formation between each screw type (PLLA vs. HA/PLLA) and adjacent tissue in both the tibia and femur was undertaken using automated image analysis (KS400, Zeiss, UK). The inflammatory response of each screw type was assessed by histological evaluation. New bone formation along the perimeter of the screw threads was statistically significantly higher with the HA/PLLA than the PLLA alone. The inflammatory response as assessed semi-quantitatively by histologically determining the number of inflammatory cells present in the tissue adjacent to the implant, was higher for PLLA than HA/PLLA. Significantly increased new bone formation and decreased inflammatory cells were observed in vivo with the composite screw in comparison with the standard polymer. A novel HA/PLLA composite biomaterial in the form of an interference screw demonstrated an improved hard-tissue response compared to PLLA in a large animal ACL reconstruction. This study determined the differences in the tissue response between PLLA and a composite material of HA/PLLA. The improved tissue related outcomes observed in vivo, may be of benefit clinically in ACL reconstruction.


Anterior cruciate ligament Bioabsorbable implants Hydroxyapatite-tricalciumphosphate composite Hydroxyapatite-polylactide Medical device 


  1. 1.
    Hovis WD, Bucholz RW (1997) Polyglycolide bioabsorbable screws in the treatment of ankle fractures. Foot Ankle Int 18:128–131PubMedGoogle Scholar
  2. 2.
    Shellock FG, Mink JH, Curtin S et al (1992) MR imaging and metallic implants for anterior cruciate ligament reconstruction: assessment of ferromagnetism and artifact. J Magn Reson Imaging 2:225–228PubMedCrossRefGoogle Scholar
  3. 3.
    Pihlajamaki H, Kinnunen J, Bostman O (1997) In vivo monitoring of the degradation process of bioresorbable polymeric implants using magnetic resonance imaging. Biomaterials 18:1311–1315PubMedCrossRefGoogle Scholar
  4. 4.
    Zantop T, Weimann A, Schmidtko R et al (2006) Graft laceration and pullout strength of soft-tissue anterior cruciate ligament reconstruction: in vitro study comparing titanium, poly-d,l-lactide, and poly-d,l-lactide-tricalcium phosphate screws. Arthroscopy 22:1204–10PubMedGoogle Scholar
  5. 5.
    Athanasiou KA, Agrawal CM, Barber FA et al (1998) Orthopaedic applications for PLA–PGA biodegradable polymers. Arthroscopy 14:726–37PubMedGoogle Scholar
  6. 6.
    Goetzen N, Lampe F, Nassut R et al (2005) Load-shift–numerical evaluation of a new design philosophy for uncemented hip prostheses. J Biomech 38:595–604PubMedCrossRefGoogle Scholar
  7. 7.
    Weiler A, Hoffmann RF, Stähelin AC et al (2000) Biodegradable implants in sports medicine: The biological base. Arthroscopy 16:305–321PubMedGoogle Scholar
  8. 8.
    Middleton JC, Tipton AJ (1998) Synthetic biodegradable polymers as medical devices. Medical Plastics and Biomaterials. Mar/Apr:31–38Google Scholar
  9. 9.
    Matthews LS, Soffer SR (1989) Pitfalls in the use of interference screws for anterior cruciate ligament reconstruction: Brief report. Arthroscopy 5:225–226PubMedGoogle Scholar
  10. 10.
    Barber FA, Dockery WD (2006) Long-term absorption of poly-l-lactic acid interference screws. Arthroscopy 22:820–826PubMedGoogle Scholar
  11. 11.
    Park MC, Tibone JE (2006) False magnetic resonance imaging persistence of a biodegradable anterior cruciate ligament interference screw with chronic inflammation after 4 years in vivo. Arthroscopy 22:911.e1–4Google Scholar
  12. 12.
    Marumo K, Sato Y, Suzuki H et al (2006) MRI study of bioabsorbable poly-l-lactic acid devices used for fixation of fracture and osteotomies. J Orthop Sci 11:154–158PubMedCrossRefGoogle Scholar
  13. 13.
    Böstman O (1992) Intense granulomatous inflammatory lesions associated with absorbable internal fixation devices made of polyglycolide in ankle fracture. Clin Orthop Relat Res 278:193–199PubMedGoogle Scholar
  14. 14.
    Frokjaer J, Moller BN (1992) Biodegradable fixation of ankle fractures. Complications in a prospective study of 25 cases. Acta Orthop Scand 63:434–436PubMedGoogle Scholar
  15. 15.
    Bostman OM, Pihlajamaki HK (2000) Adverse tissue reactions to bioabsorbable fixation devices. Clin Orthop Relat Res 371:216–227PubMedCrossRefGoogle Scholar
  16. 16.
    Gefen A (2002) Optimising the biomechanical compatibility of orthopaedic screws for fracture fixation. Med Eng Phys 24:337–347PubMedCrossRefGoogle Scholar
  17. 17.
    Ciccone WJ, Motz C, Bentley C et al (2001) Bioabsorbable implants in orthopaedics: new developments and clinical applications. J Am Acad Orthop Surg 9:280–288PubMedGoogle Scholar
  18. 18.
    Krappel FA, Bauer E, Harland U (2006) The migration of a BioScrew as a differential diagnosis of knee pain, locking after ACL reconstruction: a report of two cases. Arch Orthop Trauma Surg 126:615–620PubMedCrossRefGoogle Scholar
  19. 19.
    Baums MH, Zelle BA, Schultz W et al (2006) Intraarticular migration of a broken biodegradable interference screw after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 14:865–868PubMedCrossRefGoogle Scholar
  20. 20.
    Han I, Kim YH, Yoo JH et al (2005) Broken bioabsorbable femoral cross-pin after anterior cruciate ligament reconstruction with hamstring tendon graft: a case report. Am J Sports Med 33:1742–1745PubMedCrossRefGoogle Scholar
  21. 21.
    Moonot P, Allen P (2006) Intra-articular pullout of an interference screw after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 14:1004–1006PubMedCrossRefGoogle Scholar
  22. 22.
    Resinger C, Vecsei V, Heinz T et al (2005) The removal of a dislocated femoral interference screw through a posteromedial portal. Arthroscopy 21:1398PubMedGoogle Scholar
  23. 23.
    Sassmannshausen G, Carr CF (2003) Transcutaneous migration of a tibial bioabsorbable interference screw after anterior cruciate ligament reconstruction. Arthroscopy 19:E133–E136PubMedCrossRefGoogle Scholar
  24. 24.
    Bush-Joseph CA, Bach BR (1998) Migration of femoral interference screw after anterior cruciate ligament reconstruction. Am J Knee Surg 11:32–34PubMedGoogle Scholar
  25. 25.
    Sidhu DS, Wroble RR (1997) Intra-articular migration of a femoral interference fit screw. A complication of anterior cruciate ligament reconstruction. Am J Sports Med 25:268–271PubMedCrossRefGoogle Scholar
  26. 26.
    Agrawal CM, Athanasiou KA (1997) Technique to control pH in vicinity of biodegrading PLA-PGA implants. J Biomed Mater Res 38:105–114PubMedCrossRefGoogle Scholar
  27. 27.
    Macarini L, Murrone M, Marini S et al (2004) MRI in ACL reconstructive surgery with PDLLA bioabsorbable interference screws: evaluation of degradation and osteointegration processes of bioabsorbable screws. Radiol Med 107:47–57PubMedGoogle Scholar
  28. 28.
    Wilson TC, Kantaras A, Atay A et al (2004) Tunnel enlargement after anterior cruciate ligament surgery. Am J Sports Med 32:543–549PubMedCrossRefGoogle Scholar
  29. 29.
    Brand J, Weiler A, Caborn DN et al (2000) Graft fixation in cruciate ligament reconstruction. Am J Sports Med 28:761–774PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.UK Centre for Tissue Engineering, School of Clinical SciencesUniversity of LiverpoolLiverpoolUK

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