Rotator Cuff Repair With Magnesium Pin

Mechanical enhancement is a direct approach to enhance the bone-tendon interface (BTI) healing, which includes surgical techniques that seek to improve BTI healing through better fixation device. Favourable results would be achieved in the non-massively torn cases, improvement in the structural integrity and shoulder function were reported in the clinical studies. However, despite the improved initial biomechanical strength, high retear rate were still reported among the massive-teared patients, which indicates that enhancing the mechanical enhancement alone may not enough to promote the overall healing outcome. Other novel adjuvants to aid rotator cuff healing to promote bone tendon junction healing include growth factor supplementation, stem cells or biophysical intervention (5,6,7).

Tissue engineering is a promising strategy that would combine modern engineering techniques with novel biomaterials, cell therapy, growth factors, bioactive molecular. Enhancement of BTI healing with biomaterial, such as magnesium, may promote osteogenesis and thus improve the surgical outcome. These various approaches have been investigated in pre-clinical animal models of rotator cuff repair, yet further investigation to translate these into clinical practice is needed (8).

We have developed a magnesium pin that can be applied to the cuff repair site to improve the BTI healing.

The use of biodegradable materials as implants to stimulate healing has been developed in orthopaedics for decades. Our team and others reported that Mg-based interference screw or suture anchors could upregulate the expression of osteogenic and angiogenic factors experimentally, yet further investigation is still required to translate into clinical practice. However, the potential insufficient mechanical strength of Mg-based implants over the degradation period may result in a loss of fixation or failure of repair, which limits its clinical application. Herein, our novel magnesium pin showed good mechanical properties to be used to enhance the suture anchor commonly used for RCT repair in clinical practice. This can incorporate the benefit of an Mg-based component for its degradation and release of osteogenic and angiogenic by-products, but without the risk of compromising the integrity of the RCT repair site or the potentially osteoporotic bone at the repair site.

40 patients with rotator cuff tear scheduled for arthroscopic rotator cuff repair (ARCR) will be recruited from the Li Ka Shing Orthopaedic Specialist clinic at the Prince of Wales Hospital (PWH) Hong Kong.

Oral and written consents will be obtained from individuals who agree to participate in the study.

The recruitment period will last for 12 months and the whole project period is 2 years in total. Basic demographics, MRI assessment and Outcome Measurement Questionnaires will be carried out.

The intervention groups receive treated using magnesium pin in additional to the suture anchor used routinely in clinical practice, whereas the control group receives routine suture anchor for the treatment-as-usual (TAU). Both treatments are conducted in clinical practices that are randomly allocated to either the intervention or the control condition. Participants are therefore randomized as their allocation depends on their practice being an intervention or a control practice.

Assessments including anthropometric measurement, range of motion, shoulder muscle strength assessment, inflammation test and questionnaires will be conducted.

• Height measurement [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Weight measurement [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• BMI measurement [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Shoulder flexibility (range of motion) [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Shoulder muscle strength [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Western Ontario Rotator Cuff (WORC) Index Western Ontario Rotator Cuff (WORC) Index Index [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Constant-Murley Score [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Visual Analogue Scale (VAS) [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• Adverse events [Срок оценки: baseline, post-operative 2 weeks, 3 months, 6 months, and 12 months.]
• C-reactive protein measurement [Срок оценки: baseline, day 1 post-operatively, 2 weeks, 3 months and 6 months post-operatively]
• Calcium (Ca) measurement [Срок оценки: baseline, day 1 post-operatively, 2 weeks, 3 months and 6 months post-operatively]
• Magnesium (Mg) measurement [Срок оценки: baseline, day 1 post-operatively, 2 weeks, 3 months and 6 months post-operatively]