You are right that studies have shown there’s a fairly high failure rate after rotator cuff repair. In fact, failure of the tendon repair to heal ranges from 20 to 94 per cent. There are many known or potential risk factors, including the one you mentioned: osteoporosis (decreased bone density).
Recognizing the role of osteoporosis in rotator cuff tear healing is a fairly new research finding. Once the correlation between bone mineral density and tendon repair failure was observed, we realized patients at increased risk for failed tendon healing can be identified. Surgeons can measure bone mineral density before surgery.
With careful management of low bone mineral density it may be possible to improve the healing rate of surgically repaired rotator cuff tears. How can this be done? If you smoke or use tobacco products, you can decrease (better yet, quit!) use of tobacco products.
Also eliminating alcohol while increasing your calcium and vitamin D intake are recommended steps. Proper exercise and medications (e.g., hormone therapy) are also known to increase bone mineral density level. Since osteoporosis and rotator cuff tears are both common in older adults (especially postmenopausal women), efforts must continue to educate everyone of the importance of osteoporosis prevention.
Consult with your physician to find out what your overall risk factors are and make every effort to reduce those that are within your control. These are just a few suggestions related to your question about bone mineral density. Your physician may have some additional thoughts specific to your health.