Kinematics and functional characteristics of the Pritchard ERS unlinked total elbow arthroplasty

Matthew Ramsey, Patricia G. Neale, Bernard F. Morrey, Shawn W. O'Driscoll, Kai Nan An

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


This study examined the kinematic characteristics of the Pritchard ERS elbow-resurfacing system, with special attention paid to the effects of the radial head component. The kinematics between the ulna and humerus were assessed in 6 human cadaveric specimens by an electromagnetic tracking system throughout a full flexion/extension range of motion. The elbows were studied under 2 loading conditions, in 3 orientations (neutral, varus, and valgus), and under 4 surgical conditions. The varus/valgus and internal/external rotation laxities were used to assess the condition differences. Specifically, the maximum laxities throughout the extension motion were compared, as were the laxities at 40°, 75°, and 110° of flexion. Both the varus/valgus and internal/external rotation laxities of the ulnohumeral joint increased after total elbow arthroplasty (TEA) implantation, with and without a radial head. This increase was most evident in the extension portion of the arc of motion. At 40° of flexion, the varus/valgus laxity of the intact elbow was 4° ± 2° versus 11° ± 8° for a TEA with a radial head and 22° ± 11° for a TEA without a radial head while the elbow was being subjected to compressive loads via the biceps, brachialis, and triceps. The kinematic data demonstrate a consistent increase in laxity with the Pritchard ERS TEA. They also indicate that a radial head component is necessary for optimal tracking and stability of the ERS arthroplasty.

Original languageEnglish (US)
Pages (from-to)385-390
Number of pages6
JournalJournal of Shoulder and Elbow Surgery
Issue number4
StatePublished - 2003

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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