The proximal humerus is the rounded top portion of the humerus, the long bone in the upper arm, connecting to the shoulder blade to form the shoulder joint. Proximal humerus replacement surgery involves replacing damaged parts of this bone and the shoulder joint with artificial components. This procedure aims to alleviate severe pain and restore movement and stability, improving the patient’s ability to use their arm and reducing discomfort.
Understanding Proximal Humerus Replacement: Indications and Patient Selection
Proximal humerus replacement is a type of shoulder arthroplasty. The procedure involves removing the damaged humeral head, the ball-shaped end of the upper arm bone, and sometimes the glenoid, the socket portion of the shoulder blade. These are then replaced with prosthetic implants designed to replicate the natural joint’s structure and function.
There are different types of shoulder arthroplasty, each considered based on the extent and nature of the damage. Hemiarthroplasty involves replacing only the humeral head with a metal prosthesis, while total shoulder arthroplasty replaces both the humeral head and the glenoid with prosthetic components. Reverse total shoulder arthroplasty is another option where the ball and socket positions are switched; a ball is fixed to the glenoid, and a cup is placed in the arm bone, which can improve stability for patients with rotator cuff deficiencies.
The primary reasons for this surgery are severe damage to the proximal humerus or shoulder joint that has not responded to other treatments. Complex proximal humerus fractures are a common indication, particularly those where the bone shatters into multiple pieces. Other conditions include severe osteoarthritis or rheumatoid arthritis impacting the shoulder joint, avascular necrosis (AVN) of the humeral head, and tumors involving the proximal humerus.
Patient suitability for proximal humerus replacement is determined by several factors, including overall health, age, and tolerance for surgery and rehabilitation. The severity of pain and limitations in arm function are also assessed. This surgery is typically considered after conservative treatments, such as physical therapy and medication, have failed. Realistic expectations for recovery and outcomes also play a role.
The Surgical Procedure
Before proximal humerus replacement surgery, preparation and assessment are undertaken. This involves detailed imaging such as X-rays, CT scans, and sometimes MRI to understand the extent of the damage and to plan the precise placement of the prosthetic components. A thorough physical examination and medical clearance from other specialists are also performed to confirm the patient’s readiness for surgery.
The surgery is typically performed under general anesthesia. In some cases, a regional nerve block may also be used in conjunction with general anesthesia to help manage pain immediately after the operation. This combination helps ensure comfort during and after the surgical process.
An incision is made over the shoulder joint area, allowing the surgeon to access the underlying structures. The muscles are then carefully separated to expose the shoulder joint. The damaged bone and cartilage from the humeral head and, if necessary, the glenoid are meticulously removed. The remaining bone is then prepared to precisely fit the prosthetic implants.
The prosthetic components (humeral stem, head, and glenoid) are carefully inserted and secured. For instance, in a reverse shoulder replacement, a metal hemisphere is fixed to the shoulder socket, and a metal prosthesis with a plastic cup is implanted in the arm bone. The incision is then closed, often in layers, to promote healing. The entire procedure typically lasts one to two hours, varying by case complexity.
Post-Surgical Recovery
Immediately following proximal humerus replacement surgery, patients are closely monitored in a recovery area. Pain management is a significant focus during this initial phase, with medications provided as needed to ensure comfort. Patients typically remain in the hospital for a few days before being discharged home. The arm is usually immobilized in a sling to protect the healing joint and tissues, and the duration of sling use varies based on the specific surgical approach.
Early rehabilitation is important for recovery, with physical therapy beginning soon after surgery, sometimes within the first week. The initial phases of physical therapy focus on passive range of motion exercises, where a therapist or a device moves the arm without the patient’s muscle effort, to prevent stiffness and gently restore movement. Simple exercises like pendulum swings, where the patient leans forward and gently sways their arm in circles, are commonly introduced to encourage early, controlled motion.
As recovery progresses, the physical therapy program becomes more active and challenging. Patients gradually transition from consistent sling use to active range of motion and strengthening exercises. Adherence to the prescribed program is important for achieving the best functional outcome. Most patients need three to four months of therapy to regain significant range of motion and strength.
Managing post-operative pain is typically accomplished through prescribed medications and non-pharmacological methods like icing the surgical area. Wound care involves keeping the incision site clean and dry, with specific instructions from the surgical team regarding dressing changes and showering. General guidelines for returning to daily activities, light work, and exercise are provided, with activity levels gradually increasing over several months, often taking six months or longer for a return to more strenuous activities or sports.
Long-Term Outlook
Patients undergoing proximal humerus replacement can generally anticipate significant improvements in pain relief and increased shoulder range of motion. While full pre-injury function is not always realistic, many individuals experience substantial quality of life enhancement, allowing them to perform daily activities with greater ease. The goal is to restore a functional, pain-free shoulder that supports a more active lifestyle.
The longevity of shoulder prostheses can vary, but modern implants are designed to last for many years. Factors influencing implant lifespan include activity level, bone quality, and overall health. Studies show revision-free survival rates for total humerus replacements are around 86% at 10 and 15 years. For typical proximal humerus replacements, many patients can expect implants to function well for 10 to 15 years or longer.
While relatively uncommon, potential long-term considerations include complications such as infection around the implant, loosening of prosthetic components, or nerve injury during initial surgery. Dislocation of the implant and persistent stiffness are also possibilities. If the implant wears out or a complication arises, revision surgery may be necessary to replace or adjust components.
Ongoing management following surgery involves regular follow-up appointments with the surgeon to monitor the implant’s condition and recovery. Continued adherence to a home exercise program, often guided by a physical therapist, is encouraged to maintain shoulder strength and mobility. This consistent care helps optimize long-term outcomes and address potential issues early on.