Hemiarthroplasty of the elbow: the effect of implant size on joint congruency

• Published in: Journal of shoulder and elbow surgery Vol. 25; no. 2; pp. 297 - 303
• Main Authors: Desai, Sagar J., MD, MSc, FRCSC, Lalone, Emily, PhD, Athwal, George S., MD, FRCSC, Ferreira, Louis M., PhD, Johnson, James A., PhD, PEng, King, Graham J.W., MD, MSc, FRCSC
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2016
• Subjects: Aged; Aged, 80 and over; Algorithms; Biomechanical Phenomena; Cadaver; Elbow hemiarthroplasty; Elbow Joint - physiopathology; Elbow Joint - surgery; Epiphyses; Hemiarthroplasty - instrumentation; Humans; Humerus - physiopathology; Humerus - surgery; joint congruency; Joint Prosthesis; Male; Orthopedics; Prosthesis Design; Range of Motion, Articular; Ulna - physiopathology; Basic Science Study; Cadaver Model; joint congruency; Elbow hemiarthroplasty; Kinesiology
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2015.09.022

Background Distal humeral hemiarthroplasty is a treatment option for elbow joint disease that predominantly affects the distal humerus, including distal humerus fractures, nonunions, and avascular necrosis. The effect of hemiarthroplasty implants on joint contact has not been reported. The purpose of this in vitro study was to quantify the effects of hemiarthroplasty and implant size on ulnohumeral joint congruency. Methods Five fresh frozen cadaveric upper extremities were mounted to a custom elbow testing system. Active and passive motion were performed in dependent, horizontal, varus, and valgus positions. A registration and interbone distance algorithm was used to quantify ulnohumeral joint congruency throughout elbow flexion. Results The optimally sized hemiarthroplasty implant demonstrated the greatest joint congruency with the ulna, followed by the oversized implant, then the undersized implant. Joint congruency was greater during active vs. passive flexion, indicating that the elbow joint is more reduced in active flexion than in passive flexion. Conclusion This study demonstrates that undersized distal humeral hemiarthroplasty implants have the lowest joint congruency compared with an optimally sized or oversized implant.