Locking mechanism failure in semiconstrained total elbow arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Implant Design

Background:

• Total elbow replacement is a common procedure for end-stage elbow arthritis.
• Semiconstrained implants offer stability but can be prone to mechanical failure.
• Locking mechanism failure can lead to significant morbidity and revision surgery.

Purpose of the Study:

• To evaluate the incidence and outcomes of late locking mechanism failure in semiconstrained total elbow replacements.
• To assess the efficacy of a novel revision technique for polyethylene bushing and locking mechanism failure.

Main Methods:

• Retrospective review of 170 total elbow replacements performed between 1988 and 2000 using semiconstrained implants.
• Analysis of radiographic evidence for implant failure, specifically locking mechanism migration.
• Surgical revision of failed locking mechanisms using a custom-made locking clip via a limited approach.

Main Results:

• A 5.3% (9 of 170) incidence of late locking mechanism failure was observed, with a mean time to failure of 5.5 years.
• Eight elbows required revision surgery; 7 of these had successful revisions with no recurrence at a mean follow-up of 1.4 years.
• Revised implants in 7 patients demonstrated good or excellent outcomes using the Hospital for Special Surgery elbow scoring system, with a mean arc of motion of 130 degrees.

Conclusions:

• Late locking mechanism failure is a potential complication of semiconstrained total elbow arthroplasty.
• A limited surgical approach with a custom locking clip can effectively revise polyethylene bushing and locking mechanism failures.
• Successful revision surgery can restore good to excellent functional outcomes and range of motion in most patients.