title: Collagen application reduces complication rates of mid-substance ACL tears treated with dynamic intraligamentary stabilization.
abstract: OBJECTIVE
  Dynamic intraligamentary stabilization was recently proposed as an option for the treatment of acute ACL ruptures. The aim of this study was to investigate the feasibility of the procedure in mid-substance ACL ruptures and examine whether the additional application of a bilayer collagen I/III membrane would provide for a superior outcome.
  
  
  METHODS
  The study group consisted of patients presenting with a mid-substance ACL rupture undergoing dynamic intraligamentary stabilization using the Ligamys™ device along with application of a collagen I/III membrane to the surface of the ACL (group A, n = 23). The control group comprised a matched series of patients presenting with a mid-substance ACL rupture also treated by dynamic intraligamentary stabilization Ligamys™ repair, however, without additional collagen application (group B, n = 33). Patients were evaluated preoperatively and at 24-month follow-up for stability as well as Tegner and Lysholm scores. Knee laxity was measured as a difference in anterior translation (ΔAP) and pivot shift. Any events occurring during the follow-up period of 24 months were documented. Logistic regression of complications was performed, and adjustment undertaken where necessary.
  
  
  RESULTS
  A high total complication rate of 78.8 % was noted in group B, compared to group A (8.7 %) (p = 0.002). The addition of a collagen membrane was the only independent prognostic factor associated with reduced complications (OR 8.0, CI 2.0-32.2, p = 0.003, for collagen-free treatment). In group B, 6 patients suffered a re-rupture with subsequent instability requiring secondary hamstring reconstruction surgery, and 11 developed extension loss requiring arthroscopic debridement, whilst in group A, 2 patients required arthroscopic debridement for loss of exension, with no further encountered complication. Median Lysholm score was significantly higher in group A compared to group B (median 100 range 93-100 vs median 95 range 60-100, p = 0.03) at final follow-up.
  
  
  CONCLUSIONS
  A high complication rate following ACL Ligamys™ repair of mid-substance ruptures was noted. Application of a collagen membrane to the surface of the ACL resulted in a reduced incidence of extension deficit and re-ruptures. The results indicate that solitary ACL Ligamys™ repair does not present an appropriate treatment modality for mid-substance ACL ruptures. Collage application proved to provide healing benefits with superior clinical outcome after ACL repair.
  
  
  METHODS
  Case control study, Level III.
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Dimitrios S
authors.initials: DS
authors.lastname: Evangelopoulos
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Bern, Switzerland. sandro.kohl@gmail.com.
authors.forename: Sandro
authors.initials: S
authors.lastname: Kohl
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwienbacher
authors.affiliation: Institute for Surgical Technology and Biomechanics (ISTB), University of Bern, Bern, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gantenbein
authors.affiliation: Department of Emergency Medicine, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Aristomenis
authors.initials: A
authors.lastname: Exadaktylos
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Bern, Switzerland.|Institute for Surgical Technology and Biomechanics (ISTB), University of Bern, Bern, Switzerland.
authors.forename: Sufian S
authors.initials: SS
authors.lastname: Ahmad
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D016022:Case-Control Studies; D003094:Collagen / Q000008:administration & dosage*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control; D007719:Knee Joint / Q000601:surgery; D008297:Male; D008567:Membranes, Artificial; D012008:Recurrence; D012421:Rupture / Q000517:prevention & control; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D008567:Membranes, Artificial; D003094:Collagen
keywords: ACL; ACL reconstruction; DIS; Dynamic intraligamentary stabilization; Knee; Ligamys