Returning to high-load exercises like push-ups is a common goal for individuals recovering from shoulder surgery. Shoulder replacement, or arthroplasty, alleviates chronic pain and restores functional range of motion in a damaged joint, often due to severe arthritis or trauma. The primary concern regarding push-ups post-surgery is the long-term mechanical safety of the prosthetic implant. This article explores the surgical differences, the forces involved in a push-up, and the long-term restrictions required to protect the new joint.
Understanding Shoulder Replacement Surgery
Shoulder replacement involves replacing the damaged surfaces of the glenohumeral joint with artificial components made of metal and plastic. The two primary types of total shoulder replacement—anatomic (TSA) and reverse (RTSA)—differ fundamentally in their design and mechanical function. A TSA aims to replicate the joint’s natural shape, placing a metal ball on the humerus and a plastic socket on the glenoid.
The TSA requires an intact and functional rotator cuff to provide stability and power for movement, maintaining the shoulder’s natural center of rotation. Conversely, the RTSA is used when the rotator cuff is severely damaged or irreparable. This design reverses the natural anatomy, placing the ball on the socket side and the socket on the arm side.
This reversal medializes the center of rotation, allowing the large deltoid muscle to take over the function of the deficient rotator cuff. While this design improves stability and function in a cuff-deficient shoulder, it is less tolerant of repetitive, high-impact loads associated with pushing motions. The new joint is a mechanical device, not biological cartilage, and it comes with specific, lifelong restrictions.
Biomechanics of the Push-Up and Joint Stress
The push-up is a closed-chain, weight-bearing exercise, meaning the hand remains fixed on the ground while the body moves toward it. This movement generates significant forces transmitted directly through the wrists and elbows to the glenohumeral joint. Studies show that a standard push-up can place a load equivalent to approximately 69% to 75% of a person’s body weight onto the shoulders.
This high force is applied as a combination of compressive and shear stresses across the prosthetic joint surface. A healthy shoulder relies on the robust stability of the rotator cuff and capsule to manage these forces and maintain proper joint alignment. A prosthetic joint, especially the RTSA design, is not engineered to withstand this type of repeated, high-magnitude loading.
The standard hand position for a push-up often forces the shoulder into internal rotation and extension, which can increase the risk of component wear or dislocation, particularly with the RTSA design. The exercise necessitates robust stabilization from surrounding soft tissues, which may be compromised post-surgery. The magnitude of force involved exceeds what the components are designed to handle over the course of decades.
The Recovery Timeline and Phased Return to Strength
Post-operative recovery is a highly structured, phased process focused on protecting soft tissue healing and gradually restoring mobility. Phase 1 (0 to 6 weeks) is strictly limited to passive range of motion, where the arm is moved by a therapist or the patient’s other arm. The shoulder is often immobilized in a sling during this time to allow the surgical site to heal.
Phase 2 (6 to 12 weeks) introduces active motion, allowing the patient to move the arm using their own muscles. The initial focus is on light resistance and low-impact movements, often involving resistance bands or light weights. Phase 3, the long-term phase, usually begins after 3 months and focuses on more substantial strengthening.
Authorization to return to demanding strength training, even with light weights, is typically given around the 3-to-4-month mark, but only for open-chain exercises like shoulder raises. While soft tissues may be healed enough to begin strengthening after 6 to 12 months, this biological readiness does not override the mechanical limitations of the prosthetic joint itself. The timeline for tissue healing is separate from the lifetime requirements for implant longevity.
Long-Term Restrictions and Prosthesis Longevity
Push-ups are generally discouraged as a permanent restriction for most patients with total shoulder arthroplasty. The primary goal following replacement is to make the prosthetic joint last 10 to 20 years or more, requiring careful management of mechanical load. Repetitive, high-force activities like push-ups risk accelerating the wear of the polyethylene socket component and can lead to component loosening.
For patients with a reverse total shoulder replacement (RTSA), the restriction is more stringent, as the design is inherently less tolerant of high compressive and shear loads. The risk of early dislocation is also higher with RTSA, and push-up forces contribute to this instability. Surgeons often recommend a permanent weight limit, typically restricting patients from lifting more than 25 to 30 pounds with the surgical arm.
Safer alternatives for developing chest and triceps strength focus on open-chain movements that do not involve fixed weight-bearing. These exercises include machine chest presses, light dumbbell press variations, or wall push-ups, which significantly reduce the percentage of body weight supported. The trade-off for pain relief and restored function is the long-term commitment to load management, meaning avoiding activities that place undue mechanical stress on the synthetic joint.