INOVEDIS & RENOLIT – TAKING ROTATOR CUFF REPAIR TO THE NEXT LEVEL

As their grandson ran toward her, Laura would have liked to hug him. But her chronic shoulder pain prevents her from lifting her arm or playing with her grandchildren. Since the pain has even started to disrupt her sleep at night, she went to a doctor and was diagnosed with a “partial rotator cuff tear”. He advised against surgery and recommended physiotherapy for her, but it gave her little relief. At her next appointment, the surgeon told Laura about an innovative and more gentle procedure without having to cut the tendon first. And in fact, thanks to this technique with a new implant made from a thermoplastic polymer, the surgery was fast and successful. Just a few weeks later, Laura could finally take her grandson in her arms.

Sounds like the future? This new implant already exists: SINEFIX™ – developed by INOVEDIS and produced by RENOLIT Healthcare Beijing from PEEK (polyetheretherketone), a thermoplastic polymer. In 2023 it received FDA clearance, at the same time, the clinical trial for the approval process in Europe has started. In contrast to current arthroscopy procedures of rotator cuff tears or lesions, this procedure promises many advantages: Simplified technique, better healing, and lower cost.

WHAT EXACTLY IS THE ROTATOR CUFF?

The shoulder joint is the most mobile joint in the body. It consists of the humeral head (4) and the glenoid cavity. Unlike other joints, the shoulder joint is only secured to a small extent by bones. Instead, it is mainly muscles, tendons and ligaments that work together with the joint capsule to stabilise the joint. A special group of four tendons is responsible for the stable and powerful guidance and, above all, the centering of the joint. This group of four tendons is called the rotator cuff because it wraps around the head of the  humerus like a cuff: supraspinatus (2), infraspinatus, subscapularis (3), and teres major. The rotator cuff muscles, which run from the shoulder blade to the humerus (5), move the arm to the side and upwards, rotate it outwards and inwards and stabilize the arm on the upper body.

These tendons run directly around the joint in a narrow bony channel between the humeral head and the top outer edge of the shoulder blade, the acromion (1). Over the course of a person’s life, signs of wear and tear can initially go unnoticed in one tendon. In extreme cases, partial-thickness or full-thickness rotator cuff tears (RCTs) can occur. The Supraspinatus tendon that plays a key role in the initiation of shoulder abduction is particularly often affected.

ROTATOR CUFF TEARS – A COMMON CAUSE OF SHOULDER PAIN 

Rotator cuff disorders are among the most common musculoskeletal conditions causing severe pain, weakness, and shoulder dysfunction. Their prevalence depends not only on age, but also on factors, such as patient dexterity, history of trauma, and occupation. It ranges from 10% in the young adult population to over 60% in the 80+ generation. 

Rotator cuff tears (RTCs) may occur in young people because of a trauma, however RCTs are typically present in middle-aged or elderly people. In most cases, they can be attributed to degenerative processes, and are therefore referred to as degenerative RCTs.

INNOVATING ROTATOR CUFF REPAIR TOGETHER

Up until now, rotator cuff repair has consisted of an operation in which screw-shaped anchors are placed in the bone of the humeral head. These anchors are then used to suture the tendon in place to return it to its original position and allow the area to heal. Although this is done as minimally invasive surgery, the procedure itself is complex and is mainly performed by trained experts using cameras. The suture threads must be knotted several times in a stable manner, which constricts the tendon, restricts the blood flow, and thus makes healing more difficult. This is why re-ruptures, a further complete tear, occur at an alarmingly high rate, affecting up to 70 percent of patients, depending on the breadth of the injury.

In addition to complete rotator cuff tears, i.e., the complete detachment of the tendons from the bone, quite a large number of patients only experience a partial tear (lesion). So far, in the case of lesions, what remained of the tendon has needed to be completely separated from the bone so that the partially torn area could be treated using suture anchors.

INOVEDIS has therefore developed a new implant called SINEFIX™, which aims to improve and simplify tendon fixation. The patented system consists of a PEEK plate with two PEEK anchors and additional teeth that ensure the distance to the bone. 

This is where RENOLIT Healthcare came into play. Due to our open innovation approach RENOLIT Healthcare is always investigating new application fields for advanced polymer solutions. In the process, we became aware of INOVEDIS, which was looking for a partner to develop the SINEFIX™ implant. Amongst the various specialty polymers (PEEK, CF-PEEK, PPSU, and more) for long term implants processed at the RENOLIT Amsterdam Innovation Center and in dedicated plants, PEEK has been selected as the preferred material for the SINEFIX™ project, looking at significant advantages offered. Another convincing aspect was the successful collaboration with other customers on filaments made from these specialty polymers for 3D printed implantable orthopaedic parts.

The SINEFIX™ implant is made of medical grade PEEK, known for its biocompatibility, biostability and chemical stability. Besides, the material features good mechanical properties, bone-like stiffness, and solid resistance to environmental stress cracking. 

For the production of the plate and the fine implants, RENOLIT Healthcare was able to contribute its extensive know-how in the field of precision injection molding. With our clean rooms certificated by ISO13485, we also met the production conditions of implantable medical devices. In addition, we help our customers meet regulatory requirements, including 510K in the United States, CE in Europe, and NMPA certification in China.

EASY TO LEARN PROCEDURE FOR SURGEONS – OPTIMIZED OUTCOME FOR PATIENTS

The patented SINEFIX™ implant system was developed to treat adult patients with rotator cuff lesions of size up to 2 cm through arthroscopic reconstruction. It allows reliable re-fixation of the tendon with a simplified surgical technique and is optimized for minimally invasive surgery. In two steps, the PEEK implant can be attached in such a way that the humerus and tendon are firmly connected to one another over a large area. In doing so, the procedure aims to preserve the vitality of the tendon, improve blood circulation and thus the biological healing process. The technique is easy and quick to learn for surgeons, minimizing complications due to surgical mistakes. Additionally, it suggests significant time and cost reductions as well as improved outcomes.

A PERFECTLY FITTING PARTNERSHIP

We at RENOLIT Healthcare are very proud and grateful to be part of this exciting project with INOVEDIS. Thanks to our colleagues at all RENOLIT Healthcare sites and innovation centers for their valuable contribution to the production of the implants.