Hemiarthroplasty & Pyrocarbon Hemiarthroplasty (Partial Shoulder Replacement)

Overview

A hemiarthroplasty, or partial shoulder replacement, replaces only the ball (humeral head) and leaves the patient's own socket (glenoid) in place. Because there is no plastic socket component, there is nothing on the socket side to wear or loosen, which is appealing for younger, active patients.

The trade-off is that the natural socket can wear over time against the implant. For osteoarthritis that involves both sides of the joint, a meta-analysis found that total shoulder replacement gives better pain relief and function than hemiarthroplasty ^[1], and a systematic review of young patients reached a similar conclusion ^[2]. Hemiarthroplasty therefore works best when the socket cartilage is still healthy, such as in avascular necrosis of the humeral head, some fractures, and arthritis limited to the ball ^[3].

Pyrocarbon hemiarthroplasty uses a humeral head made of pyrolytic carbon instead of metal. Pyrocarbon is smooth and has a stiffness closer to bone, which is intended to be gentler on the native socket. In a systematic review of pyrocarbon hemiarthroplasty, motion and patient-reported outcomes improved, the revision rate was about 8%, and some socket wear was seen on X-rays at a minimum of two years; longer follow-up is still needed ^{[4, 5]}. When a hemiarthroplasty wears out, it can usually be converted to a total or reverse shoulder replacement.

Benefits

• Preserves the natural socket and avoids a plastic socket component
• Can relieve pain when the socket cartilage is healthy
• Keeps future options open, including conversion to total or reverse replacement

Who is a Candidate?

Hemiarthroplasty & Pyrocarbon may be appropriate for patients who meet certain criteria. Ideal candidates include:

• Avascular necrosis of the humeral head with a healthy socket
• Arthritis limited to the ball of the shoulder
• Younger, active patients who want to avoid a plastic socket component (pyrocarbon)
• Some proximal humerus fractures

Recovery & Rehabilitation

Most patients go home the same day or after one night. A sling is worn for several weeks while the subscapularis tendon heals, followed by therapy that progresses from gentle motion to strengthening over three to six months.

References

1. Bryant D, Litchfield R, Sandow M, et al. A comparison of pain, strength, range of motion, and functional outcomes after hemiarthroplasty and total shoulder arthroplasty in patients with osteoarthritis of the shoulder. A systematic review and meta-analysis. J Bone Joint Surg Am. 2005;87(9):1947-56. doi.org/10.2106/JBJS.D.02854
2. Sayegh ET, Mascarenhas R, Chalmers PN, et al. Surgical Treatment Options for Glenohumeral Arthritis in Young Patients: A Systematic Review and Meta-analysis. Arthroscopy. 2015;31(6):1156-1166.e8. doi.org/10.1016/j.arthro.2014.11.012
3. Ristow JJ, Ellison CM, Mickschl DJ, et al. Outcomes of shoulder replacement in humeral head avascular necrosis. J Shoulder Elbow Surg. 2019;28(1):9-14. doi.org/10.1016/j.jse.2018.06.031
4. Park CN, Zhang GX, Chang J, et al. Pyrocarbon hemiarthroplasty of the shoulder: a systematic review and meta-analysis of clinical results. J Shoulder Elbow Surg. 2023;32(6):1323-1332. doi.org/10.1016/j.jse.2022.12.005
5. Griswold BG, Berger JM, Davis BP, et al. Five-Year Radiographic and Clinical Outcomes of Pyrocarbon Hemiarthroplasty for Glenohumeral Arthritis and Osteonecrosis. J Bone Joint Surg Am. 2025;107(24):2751-2762. doi.org/10.2106/JBJS.25.00163