Cofield's 1984 prospective case series evaluated 73 total shoulder arthroplasties using the Neer prosthesis in 65 patients at 2–6.5 years follow-up. The study asked whether this less-constrained implant could reliably relieve pain and restore function while avoiding the high complication rates of earlier ball-and-socket designs. Diagnoses included osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
Before this paper, ball-and-socket constrained prostheses dominated shoulder arthroplasty — but their complication rate was prohibitive (11 reoperations in 21 cases at Mayo Clinic). Cofield validated that the less-constrained Neer design could reliably relieve pain while reducing catastrophic failures.
When you counsel a patient for total shoulder arthroplasty, the rotator cuff examination is non-negotiable. A patient with an intact cuff can expect ~143° of active abduction. A patient requiring major cuff repair at the time of arthroplasty averages only 63°. Less than functional overhead reach. This is why preoperative MRI and intraoperative cuff assessment directly shape the informed consent conversation.
On postoperative radiographs, a radiolucent line at the glenoid bone-cement junction does not automatically mean failure. Cofield showed 80% of shoulders develop some lucency, but only 8 of 73 progressed to definite loosening. The key question is whether the line is progressing and whether the patient has pain.
This paper is why glenoid component design (metal backing, improved keel geometry) became the central engineering focus of shoulder arthroplasty development for the next two decades. Cofield himself noted the limitation and began incorporating metal-backed glenoids based on these findings.
Cofield's 1984 prospective case series evaluated 73 total shoulder arthroplasties using the Neer prosthesis in 65 patients at 2–6.5 years follow-up. The study asked whether this less-constrained implant could reliably relieve pain and restore function while avoiding the high complication rates of earlier ball-and-socket designs. Diagnoses included osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
Before this paper, ball-and-socket constrained prostheses dominated shoulder arthroplasty — but their complication rate was prohibitive (11 reoperations in 21 cases at Mayo Clinic). Cofield validated that the less-constrained Neer design could reliably relieve pain while reducing catastrophic failures.
When you counsel a patient for total shoulder arthroplasty, the rotator cuff examination is non-negotiable. A patient with an intact cuff can expect ~143° of active abduction. A patient requiring major cuff repair at the time of arthroplasty averages only 63°. Less than functional overhead reach. This is why preoperative MRI and intraoperative cuff assessment directly shape the informed consent conversation.
On postoperative radiographs, a radiolucent line at the glenoid bone-cement junction does not automatically mean failure. Cofield showed 80% of shoulders develop some lucency, but only 8 of 73 progressed to definite loosening. The key question is whether the line is progressing and whether the patient has pain.
This paper is why glenoid component design (metal backing, improved keel geometry) became the central engineering focus of shoulder arthroplasty development for the next two decades. Cofield himself noted the limitation and began incorporating metal-backed glenoids based on these findings.