Kathleen Dailey1, Andy Carter, PhD1,2, William R. Walsh, PhD2, Ivan Popoff, MD3,6, Doron Sher, MD3,6, Kenneth Cutbush, MD4, Ashish Gupta, MD5, Jerome Goldberg, MD6
- Tetrous, Inc., 14930 Ventura Blvd., Suite #325, Sherman Oaks, CA USA
- Surgical and Orthopaedic Research Laboratories, School of Clinical Medicine, University of New South Wales (UNSW) Sydney, Australia
- UNSW, Sydney, Australia
- Queensland University of Technology, Orthopaedic Department, Cairns Base Hospital. Shoulder Clinic, St Andrew’s War Memorial Hospital, Brisbane, Australia
- Queensland Unit for Advanced Shoulder Research, University of Technology, Orthopaedic Department, Cairns Base Hospital. Shoulder Clinic St Andrew’s War Memorial Hospital, Brisbane, Australia
- Orthosports, Sydney, Australia
Tetrous presented a workshop on the EnFix® product line for improving outcomes in enthesis failure syndrome at the 2024 Shoulder and Elbow Society of Australia (SESA) meeting in Brisbane. SESA brought together leading orthopedic surgeons, researchers, and industry professionals to share insights on the latest surgical methods, clinical advancements, and implant technologies aimed at improving patient outcomes in upper extremity care.
Tetrous’ EnFix Implant: Revolutionizing Bone-to-Tendon Healing and Advancing Orthobiologics
Tetrous’ EnFix implant, the sole recipient of the 2024 ACE Award for Accelerating the Cutting Edge, is redefining the field of bone-to-tendon healing and setting a new benchmark in orthobiologics. The EnFix implants have groundbreaking potential across enthesis repair procedures. Tetrous presented a talk on the biological significance of the product for enthesis reformation and four surgeons with extensive experience using the implant presented their surgical procedures and clinical results over the past year at the SESA meeting.
The talks highlighted how EnFix demonstrates a significant capacity to enhance both biological healing and structural stability, including cuff thickening, establishing it as a transformative advancement in orthopedic care with minimal change to technique.
Dr. Andy Carter Explains EnFix’s Role in Bone-to-Tendon Healing
Dr. Carter, Co-Founder and Chief Technology Officer at Tetrous, shared findings on the use of EnFix for tendon reattachment to bone. In his presentation, Dr. Carter explained how the EnFix implant consists of demineralized bone fibers (DBF), a material known for its osteoinductive and osteoconductive properties, and promotes endochondral ossification—the natural bone-forming process. This process replicates the process that occurs in enthesis development in the embryo, promoting functional tendon-bone integration in repairs, unlike traditional methods that often result in formation of scar tissue.
Dr. Carter presented preclinical rabbit data demonstrating that EnFix results in histological evidence of enthesis reformation, including collagen fibrils extending from the bone into the tendon, shown in Figure 1.
Figure 1. Histological evidence at 12 weeks demonstrating enthesis reformation in the EnFix-treated group, with collagen fibrils extending from bone-to-tendon in a rabbit model.
Biomechanical testing corroborated these findings, showing that this structural recreation significantly strengthens the repair compared to the scar tissue that forms with traditional repair methods. Figure 2 illustrates a rabbit infraspinatus repair study where there is an improvement in strength of the biological structure over time with EnFix. The tendon was detached and re-attached using suture fixation through two bone tunnels, with a DBF sheet placed between the tendon and bone in the treated group. Mechanical testing, conducted after cutting the sutures thus isolating the properties of the tendon-bone interface, showed that the DBF improved over time (P<0.05), where the control group was not statistically higher at 6 and 12 weeks.
Figure 2. Biomechanical testing of a rabbit infraspinatus repair study showing increased strength with EnFix over time.
Figure 3. EnFix TAC and RC implants for enthesis repair.
Since the controlled launch of EnFix in June 2023, over 225 surgeries have been performed by seven surgeons in Australia and the United States, with more than 400 implants utilized. Dr. Carter reported overwhelmingly positive feedback from surgeons, who noted improved patient outcomes, and six-month MRI follow-ups demonstrated promising results, further validating the implant’s effectiveness.
Dr. Ken Cutbush Highlights EnFix’s Versatility in Rotator Cuff and Biceps Tendon Repairs
Dr. Cutbush discussed the revolutionary impact of EnFix on rotator cuff repair, citing a case study in which a 64-year-old patient demonstrated complete healing of the rotator cuff with excellent signal seen in the tendon at the 3-month MRI, suggesting rapid tendon healing, shown in Figure 4. This restoration of bone-to-tendon attachment, driven by EnFix’s properties, showed the implant’s ability to enhance the biological integration and biomechanical stability necessary for successful repairs.
Figure 4. Case study of a 64-year-old patient demonstrating progression enthesis regeneration (arrows) following rotator cuff repair with EnFix.
The versatility of EnFix in various surgical scenarios, including arthroscopic suprapectoral biceps tenodesis, was also emphasized by Dr. Cutbush. His presentation underscored the implant’s ability to augment healing of the biceps tendon at the humeral head, offering surgeons a reliable solution across different bone-to-tendon repair scenarios.
Dr. Ivan Popoff Discusses EnFix’s Clinical Success in Reducing Failure Rates
Dr. Popoff presented clinical data highlighting integration of EnFix into existing surgical workflows. He shared an analysis of his clinical case load showing a significant 36% reduction in failure rates for rotator cuff repairs after 12 months, from 8.3% without EnFix to 5.3% with EnFix. An example of pre-op and six-month post-op MRIs is shown in Figure 5. This improvement supports EnFix’s role in increasing repair durability and accelerating the healing process.
Figure 5. Pre-op and six-month post-op MRI results showing rotator cuff healing with EnFix.
Dr. Doron Sher Demonstrates EnFix’s Versatility in Surgical Techniques
Dr. Sher focused on the implant’s adaptability, noting that it can be easily integrated into various surgical techniques, such as single-row, double-row, and medial-to-lateral anchor placements. This versatility makes EnFix an invaluable tool for a wide range of rotator cuff repairs, enabling surgeons to enhance healing outcomes across different tear patterns and complexities. Dr. Sher also highlighted the use of EnFix RC in patients with poor bone quality and, in particular, revision cases.
Dr. Ashish Gupta Presents EnFix Augmentation for Massive Rotator Cuff Tears
Dr. Gupta’s presentation centered on using EnFix to enhance outcomes in massive rotator cuff tears. His study, which compared two patient groups undergoing arthroscopic repair with and without EnFix, demonstrated that the EnFix group achieved superior tendon outcomes on the Sugaya scale, with 5.6% of patients achieving excellent results (Sugaya 1) and 61.1% achieving good results (Sugaya 2), compared to the control group, which showed no Sugaya 1 results, shown in Table 1.
Table 1. Rotator cuff repair with augmentation using DBF implant
| With (n=18) | Without (n=18) | |
|---|---|---|
Mean Tendon Thickness | 4.4 mm | 4.3 mm |
Healing | 100% | 100% |
Tendon Integrity |
|
|
Dr. Gupta’s data also indicated that EnFix patients reported lower pain levels and higher functional recovery scores, shown in Figure 6, reinforcing the implant’s potential to improve both structural integrity and functional recovery for patients with complex rotator cuff injuries.
Functional recovery was assessed using validated scoring systems:
- Visual Analog Scale (VAS): A subjective tool for measuring pain intensity on a 10-cm continuum from 0 (no pain) to 10 (worst pain)2. EnFix patients reported significantly lower scores, indicating reduced pain levels.
- American Shoulder and Elbow Surgeons (ASES) Score: A 100-point patient-reported scale assessing pain and physical function3. The EnFix group demonstrated higher scores, reflecting better function and satisfaction.
- Constant-Murley Score (Constant): A 100-point assessment comprising pain, activities of daily living, strength, and range of motion.4 EnFix patients showed improved shoulder strength and mobility.
- UCLA Shoulder Rating Scale: A 35-point combined subjective (pain, satisfaction, function) and objective (active flexion, strength) evaluation tool.5 Higher scores in the EnFix group highlighted superior recovery outcomes.
Patients in the Enfix group consistently reported less pain and greater functional improvements compared to the control group, underscoring the clinical value of DBF augmentation.
Figure 6. Comparison of recovery scores between groups with EnFix and control groups without EnFix. EnFix patients showed lower pain (VAS), higher function (ASES), better strength and mobility (Constant), and superior overall recovery (UCLA).
Dr. Gupta’s work demonstrates how EnFix augmentation has the potential to redefine the standard of care for complex rotator cuff injuries, offering a robust solution for improved long-term outcomes.
Looking Forward
The 2024 SESA meeting showcased the transformative potential of Tetrous’ EnFix implants in rotator cuff repair and bone-to-tendon healing. With the ability of these grafts to integrate seamlessly into existing surgical workflows, reduce failure rates, and enhance both biological healing and biomechanical stability, EnFix is positioned to redefine the standard of care in sports medicine. These advancements highlight the importance of continued innovation and collaboration in improving patient outcomes and advancing orthopedic care.
1 Bessa, P. C., Casal, M., & Reis, R. L. (2008). Bone morphogenetic proteins in tissue engineering: the road from the laboratory to the clinic, part I (basic concepts). J Tissue Eng Regen Med 2008(2), 1–13. Wiley InterScience. https://doi.org/10.1002/term.63
2 https://www.physio-pedia.com/
Visual_Analogue_Scale
4 https://www.physio-pedia.com/Constant-Murley_Shoulder_Outcome_Score
