What Does Irreparability Mean?
When the tendon(s) of the rotator cuff are torn, the associated muscles undergo degeneration (aging). This results in muscle atrophy (shrinkage) and fatty infiltration. These degenerative changes occur independently of inactivity or a high-fat diet and can even affect very slim individuals.
In a healthy state, the tendon and muscle form an elastic unit, comparable to a rubber band. If the tendon tears completely, its elasticity allows it to be retracted back to its attachment site, where it can heal under minimal tension. As long as the muscle-tendon unit has not undergone significant fatty infiltration, it remains elastic, and repair is possible.
Over time, however, progressive fatty infiltration and muscle atrophy lead to stiffness in the elastic muscle-tendon unit—similar to a leather belt. In this condition, it is often impossible to restore the tendon to its attachment site. Even if reattachment is achieved, there is a high risk that the tendon will fail to heal due to excessive tension.
Fatty infiltration is classified into five grades (0 to IV) according to the French physician Goutallier. The higher the grade, the worse the prognosis. From Goutallier Grade II onwards, repair is generally deemed futile, and the tears are classified as irreparable.
How Quickly Does a Repairable Tear Become Irreparable?
The rate of fatty infiltration and muscle atrophy is unpredictable. Studies show that small tears can sometimes rapidly increase in size, while large tears may show little to no progression of fatty infiltration even after several years. As such, it is impossible to accurately predict the timeline for the degeneration of the muscle-tendon unit.
Due to this uncertainty, early repair is recommended for complete tears causing symptoms in patients with good muscle quality (repairability), as the prognosis in these cases is excellent.
How Can an Irreparable Rotator Cuff Tear Be Treated?
If patients are pain-free and can perform their daily activities without limitation, surgery is not necessary. However, for patients experiencing reduced quality of life due to pain or poor function, biologically younger patients may benefit from a tendon transfer. In this procedure, the irreparable tendon is replaced by another tendon to preserve shoulder function.
The feasibility of a tendon transfer depends on various factors that a shoulder specialist evaluates using clinical examinations and imaging (X-rays, MRI). Factors include shoulder stiffness, the number of irreparable tendons, and the condition of the joint. Success rates for tendon transfer are approximately 70%, and long-term outcomes, especially with Latissimus dorsi tendon transfer, are consistently good. However, it is essential to set realistic expectations, as 30% of cases may not achieve the desired outcome.
If a tendon transfer is not possible, the final option is a reverse shoulder arthroplasty.
What Can a Reverse Shoulder Arthroplasty Achieve (and What Can It Not)?
A reverse shoulder arthroplasty is primarily used for patients over 60 years old with multiple irreparable rotator cuff tears. The success rate, as measured by patient satisfaction one year after surgery, is between 90% and 95%. Patients frequently report significant pain relief and improved overhead arm function.
While the prosthesis can alleviate pain and enhance upward arm movement, it has limitations in rotational movements (external and internal rotation), which are difficult to predict. These limitations must be clearly communicated before surgery.
Risk factors for unsatisfactory outcomes include younger age (especially under 50), a history of joint infections, multiple prior surgeries, and shoulder stiffness.
How Long Does a Reverse Shoulder Arthroplasty Last?
Data from large joint registries, such as the Australian registry, indicate that after 10 years, 93% of patients still have the same prosthesis, and after 20 years, this figure is 83%. Reasons for premature revision may include infections, instability, loosening, or fractures.
With advancements in surgical techniques and materials, the longevity of prostheses is expected to improve further, although this will require confirmation from future studies.