Reverse Shoulder Replacement: Key Contraindications and Candidacy Considerations

Who is not a good candidate for reverse shoulder replacement?

A reverse shoulder replacement is a highly specialized surgical procedure, and not all individuals suffering from shoulder pain or dysfunction are suitable candidates, particularly those with intact rotator cuffs, compromised deltoid function, or significant medical comorbidities.

Understanding Reverse Shoulder Replacement

Reverse shoulder replacement, or reverse total shoulder arthroplasty (RTSA), is a unique surgical procedure designed primarily for individuals with significant shoulder dysfunction stemming from irreparable rotator cuff tears combined with severe arthritis (rotator cuff arthropathy). Unlike traditional shoulder replacement, which mimics the natural ball-and-socket anatomy, RTSA reverses it: a "ball" is placed on the shoulder blade (scapula), and a "socket" is placed on the upper arm bone (humerus). This alteration allows the deltoid muscle, rather than the damaged rotator cuff, to become the primary mover of the arm, restoring overhead motion and reducing pain. Given its specific biomechanical principles, the criteria for candidacy are stringent.

Primary Contraindications for Reverse Shoulder Replacement

Certain conditions make a patient definitively unsuitable for a reverse shoulder replacement, as the procedure's success fundamentally relies on specific anatomical and physiological prerequisites.

• Intact or Repairable Rotator Cuff: The primary indication for RTSA is an irreparable rotator cuff tear with associated arthritis. If a patient has an intact rotator cuff or one that can be successfully repaired, a traditional shoulder replacement or rotator cuff repair is typically the preferred and more appropriate surgical approach. RTSA alters the shoulder's natural biomechanics, which is unnecessary and potentially detrimental if the rotator cuff can still function.
• Compromised Deltoid Muscle Function: The deltoid muscle is paramount for the function of a reverse shoulder replacement. After RTSA, the deltoid takes over the role of the damaged rotator cuff in elevating and moving the arm. If the deltoid muscle is significantly weak, paralyzed, or otherwise compromised (e.g., due to nerve injury or severe atrophy), the patient will be unable to effectively utilize the new joint, leading to poor functional outcomes and potential instability.
• Insufficient Bone Stock (Glenoid or Humeral): The success of the implant depends on its secure fixation to healthy bone.
  • Glenoid Bone Stock: The glenoid (shoulder socket) must have sufficient bone quality and quantity to support the baseplate of the "ball" component. Severe glenoid bone loss, often due to advanced arthritis, infection, or previous surgery, can make stable fixation impossible.
  • Humeral Bone Stock: Similarly, the humeral shaft must have adequate bone to secure the "socket" component. Significant bone defects or severe osteoporosis can compromise implant stability.
• Active Infection in the Shoulder Joint: Any active infection in or around the shoulder joint is an absolute contraindication. Implanting a prosthetic joint into an infected environment almost guarantees failure and can lead to severe, life-threatening complications. Infection must be completely eradicated before any joint replacement surgery can be considered.
• Neuropathic Arthropathy (Charcot Joint): This condition involves progressive joint destruction due to nerve damage, leading to loss of protective sensation and repeated microtrauma. The bone and joint structures are severely compromised and unstable, making stable implant fixation virtually impossible and leading to a high risk of failure and dislocation.
• Unrealistic Patient Expectations or Non-Compliance: Successful recovery from RTSA requires significant patient commitment to a structured rehabilitation program. Patients who have unrealistic expectations about the level of function they will regain or who are unlikely to comply with post-operative restrictions and physical therapy protocols are not good candidates, as their outcomes will likely be poor.

Relative Contraindications and Considerations

While not absolute contraindications, certain factors can increase the risks associated with reverse shoulder replacement or negatively impact outcomes, requiring careful consideration by the surgical team.

• Significant Neurological Deficits (e.g., Paralysis from Stroke, Brachial Plexus Injury): While a completely non-functional deltoid is an absolute contraindication, other neurological conditions affecting shoulder function can make RTSA challenging. The success of the surgery relies on the patient's ability to participate in rehabilitation and control the deltoid muscle.
• Severe Medical Comorbidities: Patients with significant underlying health conditions, such as severe heart disease, lung disease, uncontrolled diabetes, or kidney failure, may be at a much higher risk for surgical complications (e.g., anesthesia risks, infection, poor wound healing) and may not tolerate the stress of a major surgery and rehabilitation.
• Younger Age: While there's no strict age cut-off, RTSA is typically performed in older adults. In younger, more active individuals, the long-term durability of the implant is a concern, as the implants may wear out over a longer lifespan, potentially requiring revision surgery.
• Previous Failed Shoulder Arthroplasty (Complex Revisions): While RTSA is sometimes used as a salvage procedure for failed traditional shoulder replacements, these revision surgeries are significantly more complex, carry higher risks, and may have less predictable outcomes due to altered anatomy, bone loss, or scar tissue.
• Active Substance Abuse or Mental Health Issues: These conditions can severely impair a patient's ability to understand and adhere to pre- and post-operative instructions, manage pain, and participate effectively in rehabilitation, thus jeopardizing the surgical outcome.

Importance of Comprehensive Surgical Evaluation

Determining candidacy for reverse shoulder replacement is a complex process that requires a thorough evaluation by an experienced orthopedic surgeon specializing in shoulder surgery. This evaluation typically includes:

• Detailed Medical History: Assessment of all past and current medical conditions, medications, and previous surgeries.
• Comprehensive Physical Examination: Assessment of shoulder range of motion, strength, stability, and neurological function.
• Advanced Imaging Studies: X-rays, MRI, and often CT scans are crucial to assess bone quality, rotator cuff integrity, deltoid status, and the extent of arthritis and bone loss.
• Discussion of Patient Goals and Expectations: Ensuring alignment between what the patient hopes to achieve and what the surgery can realistically deliver.

A multidisciplinary approach, involving discussions with primary care physicians, cardiologists, or other specialists, may also be necessary to optimize a patient's health before surgery. Ultimately, the decision to proceed with a reverse shoulder replacement is highly individualized, balancing the potential benefits against the risks and contraindications specific to each patient.