Introduction
When a person suffers from advanced shoulder arthritis—especially when the rotator cuff is also damaged and the socket side (glenoid) of the shoulder is severely worn away—conventional shoulder replacements often don’t work. In such cases, placing a standard implant is difficult or even impossible. To offer hope in these complex situations, surgeons have developed a custom-made shoulder implant that draws inspiration from hip replacement designs. This solution uses 3D technology to create an implant that is specifically tailored to the patient’s bone structure, allowing for more secure fixation and improved function.
Why a Custom Implant?
Patients with severe shoulder joint damage often have bone loss so extensive that typical implants won’t stay in place or perform well. Traditional solutions like bone grafts or reverse shoulder replacements may not be reliable if too much of the socket has eroded.
This custom shoulder implant uses computer-aided design and manufacturing (CAD-CAM) to build a prosthesis tailored to each patient’s anatomy. Unlike traditional implants, this one attaches around the glenoid socket instead of directly into it—making it ideal when large parts of the bone are missing.
Who is a Candidate?
This specialized implant is intended for patients who:
- Have severe glenoid bone loss not fixable with standard implants
- Experience debilitating pain and limited function
- Have already tried non-surgical treatments for at least a year
- Suffer from rotator cuff-deficient arthritis, rheumatoid arthritis, post-traumatic arthritis, or congenital shoulder deformities
How the Custom Implant is Made
Each implant is uniquely designed using a detailed CT scan of the patient’s shoulder. Based on this scan, a personalized implant is created that includes:
- A titanium glenoid “shell” shaped like a hip socket
- A polyethylene (plastic) liner that fits inside the shell
- A specially designed humeral stem and head to match the upper arm bone
Surgical Technique
The surgery is performed under general anesthesia with a nerve block for added comfort. The surgeon accesses the shoulder from the front and carefully prepares the area by removing damaged tissue and preserving important structures like the axillary nerve.
Key steps include:
- Cutting and reshaping the upper arm bone (humerus) to fit the stem
- Creating a new socket area on the scapula using special reamers
- Securing the titanium glenoid shell to the scapula with screws angled for maximum grip
- Cementing the plastic liner into the shell
- Inserting and aligning the humeral stem and head for proper joint movement
After implanting the components, the surgeon checks for stability and a smooth range of motion before closing the wound.
Recovery and Rehabilitation
- First 6 weeks: Arm is kept in a sling to allow healing. Gentle movements are guided by a therapist.
- 6 to 12 weeks: Strengthening begins, especially for the deltoid muscle.
- After 12 weeks: More advanced exercises restore functional movement.
Patients can usually return to light daily activities in a few months, though overhead lifting may remain limited.
Results and Functional Improvement
At an average of 5 years after surgery, most patients reported:
- Significant pain relief (pain scores dropped from 9.2 to 2.4)
- Improved function (Oxford Shoulder Score improved from 11 to 27)
- Increased ability to perform daily activities
- Better motion: shoulder elevation improved from 39° to 64°, and external rotation from 6° to 15°
- Over half of the patients could reach essential areas like the mouth, opposite armpit, and same-side buttock after surgery (a function known as the “functional triangle”)
Complications and Risks
As with any major surgery, there are risks. In this study:
- 24% of patients needed further surgery
- 6 patients had issues with implant components (loosening, dislocation, fracture)
- Some had pain due to screw placement or other minor complications
Fortunately, in most cases, the implant remained secure, and the issues were manageable with additional procedures.
When Should This Implant Be Considered?
This custom solution is not for everyone. It is specifically recommended only when no standard implants can be securely fixed due to the degree of bone loss. It is not intended to replace reverse or anatomic total shoulder replacements in routine cases. Instead, it fills an important gap for patients with complex anatomy or failed previous surgeries.
Summary
For patients with severely damaged shoulder sockets and limited options, a custom-made shoulder implant inspired by hip designs offers a promising alternative. It provides pain relief, functional improvement, and long-term stability when standard methods fail. Although complications can occur, the tailored design allows surgeons to overcome anatomical challenges and restore meaningful use of the arm.
