An interventional study of Revision ACL Reconstruction With Achilles Tendon Allograft and InternalBrace Augmentation and Revision ACL Reconstruction With Achilles Tendon Allograft Without InternalBrace Augmentation in Anterior Cruciate Ligament Injury, Anterior Cruciate Ligament Rupture and Anterior Cruciate Ligament Graft Failure, sponsored by Medical University of Graz. Completed at 1 site in Austria. Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-05-08.
Sponsored by Medical University of Graz · Not applicable, Interventional, and Treatment
This study evaluated outcomes after revision anterior cruciate ligament reconstruction using Achilles tendon allografts with a calcaneal bone block, with or without additional InternalBrace augmentation. Revision ACL reconstruction is often more complex than primary ACL reconstruction because previous surgery may leave widened bone tunnels or bone defects. Achilles tendon allografts with attached bone blocks may help address these defects and allow reconstruction in a single surgical procedure.
Participants with MRI-confirmed ACL graft re-tear and clinical knee instability were randomized to undergo revision ACL reconstruction either with InternalBrace augmentation or without InternalBrace augmentation. Clinical outcomes, patient-reported knee function, health-related quality of life, and MRI findings were assessed during 13 months of follow-up. The study was designed as a prospective randomized controlled pilot trial to compare whether additional InternalBrace augmentation improved functional, radiographic, or quality-of-life outcomes after revision ACL surgery.
Anterior cruciate ligament revision surgery remains challenging and may have less predictable outcomes than primary ACL reconstruction. In revision cases, prior bone tunnels and bone defects can complicate graft fixation. Achilles tendon allografts with calcaneal bone blocks provide a reliable graft configuration and may help fill pre-existing bone defects during a one-stage revision procedure. InternalBrace augmentation is intended to provide additional support to the reconstructed ligament during the healing period, but clinical evidence for its use with allograft ACL revision surgery is limited.
This prospective, randomized controlled pilot study enrolled patients from February 2017 to September 2020 at the Medical University of Graz. Eligible participants had MRI-confirmed re-tear of the ACL graft and clinical and patient-reported knee instability. Patients with advanced associated lesions requiring reconstruction or prolonged restricted weight bearing, signs of infection, advanced osteoarthritis, or neuromuscular disease were excluded. For all included participants, the procedure was the first revision surgery on the affected knee. The study was approved by the Ethics Committee of the Medical University of Graz, and written informed consent was obtained before participation.
All participants underwent revision ACL reconstruction using an Achilles tendon allograft with a calcaneal bone block. Participants were randomized in a 1:1 ratio to receive either additional InternalBrace augmentation or no InternalBrace augmentation. The InternalBrace group received a non-resorbable polyethylene FiberTape fixed separately and independently from the ACL graft. Apart from the additional InternalBrace fixation in one group, the surgical technique and postoperative rehabilitation protocol were the same for all participants.
Clinical and patient-reported outcomes were assessed preoperatively and at 6 weeks, 12 weeks, 6 months, and 13 months after surgery. Outcome measures included the International Knee Documentation Committee score, Lysholm Knee Questionnaire, Tegner Activity Scale, Knee Injury and Osteoarthritis Outcome Score, and Short Form-36. MRI scans were performed before surgery and 13 months after surgery to assess graft appearance, graft tightness, graft signal, ligament signs at the femoral and tibial tunnel insertions, and tunnel size.
The final analyzed study population included 30 participants, with 16 participants in the InternalBrace group and 14 participants in the non-InternalBrace group. Overall, clinical and patient-reported outcomes improved during follow-up. At the final 13-month follow-up, there were no clinically relevant differences between the InternalBrace and non-InternalBrace groups. Postoperative MRI showed elongated or insufficient ACL allografts in 15 of 30 participants, without significant differences between groups. The study concluded that ACL revision surgery using Achilles tendon allografts with bone blocks resulted in improved clinical outcomes at 13 months, but additional InternalBrace augmentation did not improve objective or subjective outcomes in this pilot trial.
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This study's enrollment of 32 is below the median of 56 across 373 interventional studies indexed under Anterior Cruciate Ligament Injuries.
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Exclusion Criteria:
Participants underwent revision anterior cruciate ligament reconstruction using an Achilles tendon allograft with calcaneal bone block and additional InternalBrace augmentation. The InternalBrace consisted of non-resorbable polyethylene FiberTape fixed separately and independently from the ACL allograft.
Procedure: Revision ACL Reconstruction With Achilles Tendon Allograft and InternalBrace Augmentation
Participants underwent revision anterior cruciate ligament reconstruction using an Achilles tendon allograft with calcaneal bone block without additional InternalBrace augmentation. Apart from the InternalBrace augmentation, the surgical technique and postoperative rehabilitation protocol were the same as in the InternalBrace group.
Procedure: Revision ACL Reconstruction With Achilles Tendon Allograft Without InternalBrace Augmentation
Revision anterior cruciate ligament reconstruction was performed using an Achilles tendon allograft with calcaneal bone block. In this group, a non-resorbable polyethylene FiberTape InternalBrace was additionally fixed separately and independently from the ACL allograft to support the graft during healing.
Also known as: Revision ACL Reconstruction With InternalBrace, ACL Revision Surgery With InternalBrace Augmentation, Achilles Tendon Allograft ACL Revision With Suture Tape Augmentation
Revision anterior cruciate ligament reconstruction was performed using an Achilles tendon allograft with calcaneal bone block. No additional InternalBrace or suture tape augmentation was used. Apart from the absence of InternalBrace augmentation, the surgical technique and postoperative rehabilitation protocol were the same as in the InternalBrace augmentation group.
Also known as: Revision ACL Reconstruction Without InternalBrace, ACL Revision Surgery Without InternalBrace Augmentation, Achilles Tendon Allograft ACL Revision Without Suture Tape Augmentation
International Knee Documentation Committee Score
The International Knee Documentation Committee score was used to assess patient-reported knee symptoms, function, and sports activity after revision anterior cruciate ligament reconstruction. Scores range from 0 to 100, with higher scores indicating better knee function.
Time frame: Preoperative baseline to 13 months after surgery
Lysholm Knee Questionnaire Score
The Lysholm Knee Questionnaire was used to assess knee symptoms and functional limitations after revision anterior cruciate ligament reconstruction. Scores range from 0 to 100, with higher scores indicating better knee function.
Time frame: Preoperative baseline to 13 months after surgery
Tegner Activity Scale Score
The Tegner Activity Scale was used to assess participant activity level after revision anterior cruciate ligament reconstruction. Scores range from 0 to 10, with higher scores indicating a higher activity level.
Time frame: Preoperative baseline to 13 months after surgery
Knee Injury and Osteoarthritis Outcome Score
The Knee Injury and Osteoarthritis Outcome Score was used to assess knee-related pain, symptoms, activities of daily living, sport and recreation function, and knee-related quality of life. Subscale scores range from 0 to 100, with higher scores indicating better outcomes.
Time frame: Preoperative baseline to 13 months after surgery
Short Form-36 Physical Component Summary Score
The Short Form-36 Physical Component Summary score was used to assess physical health-related quality of life after revision anterior cruciate ligament reconstruction. Scores range from 0 to 100, with higher scores indicating better physical health-related quality of life.
Time frame: Preoperative baseline to 13 months after surgery
Short Form-36 Mental Component Summary Score
The Short Form-36 Mental Component Summary score was used to assess mental health-related quality of life after revision anterior cruciate ligament reconstruction. Scores range from 0 to 100, with higher scores indicating better mental health-related quality of life.
Time frame: Preoperative baseline to 13 months after surgery
MRI Assessment of ACL Allograft Tightness
Postoperative magnetic resonance imaging was used to assess anterior cruciate ligament allograft tightness. Grafts were categorized as tight, elongated, or insufficient.
Time frame: 13 months after surgery
MRI Assessment of Femoral and Tibial Tunnel Size
Postoperative magnetic resonance imaging was used to measure femoral and tibial tunnel size after revision anterior cruciate ligament reconstruction. Tunnel size was measured in millimeters.
Time frame: 13 months after surgery
Plan to share: Yes — De-identified individual participant data underlying the results reported in the publication will be shared upon reasonable request. Shared data may include baseline characteristics, group allocation, clinical outcome scores, patient-reported outcome measures, health-related quality-of-life scores, and MRI assessment data.
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