Effectiveness of the Lateral Unilateral Dynamic External Fixator After Elbow Ligament Injury (original) (raw)

Abstract

The optimum management of ligamentous injuries of the elbow is not known. Use of dynamic external fixators has been advocated to stabilize the joint while maintaining motion, but there are no published data to corroborate their efficacy. The purpose of this study was to test the hypothesis that a laterally applied unilateral dynamic external fixator is capable of stabilizing and restoring normal kinematics to elbows with varying degrees of soft-tissue injury. Six fresh-frozen cadaveric upper extremities, from donors who were an average of seventy-six years of age at the time of death, were tested in a custom apparatus with an electromagnetic tracking device to analyze the kinematic behavior. Testing began with an injury of either the lateral or the medial collateral ligament, which was followed by a second test with an injury to the ligament on the contralateral side of the joint. In each test, the varus-valgus displacement and the forearm rotatory displacement were measured through the arc of elbow flexion under three loading conditions (hand weight alone, hand weight plus 3.5 N, and hand weight plus 7 N). After each test (with each injury), a unilateral external fixator was applied from the lateral aspect of the elbow, and the same measurements were conducted under the three loading conditions across the elbow joint. With varus stress testing, both after injury of the medial collateral ligament alone and after injury of the lateral collateral ligament and extensor mass alone, the laterally applied unilateral dynamic external fixator was capable of maintaining the displacements within the laxity envelope of an uninjured elbow. With valgus stress testing, after either lateral or medial ligamentous injury, the fixator was unable to maintain displacements within the normal laxity envelope when a 7-N load was applied to the elbow. When both medial and lateral injuries were present, the lateral fixator maintained varus displacement within normal limits, but valgus displacement was consistently maintained within normal limits only when no additional load was applied to the forearm. A lateral dynamic elbow external fixator is capable of maintaining varus displacements within normal limits in the presence of medial and lateral collateral ligament injuries and with a 7-N load added to the limb. However, valgus displacement is only consistently maintained within normal limits if no additional displacement force is added to the weight of the hand and forearm. The maintenance of valgus displacement is more sensitive to additional load and specifically to the extent of medial soft-tissue injury.

Loading...

Loading Preview

Sorry, preview is currently unavailable. You can download the paper by clicking the button above.

References (15)

  1. Ring D, Jupiter JB. Compass hinge fixator for acute and chronic instability of the elbow. Oper Orthop Traumatol. 2005;17:143-57.
  2. Stavlas P , Gliatis J, Polyzois V, Polyzois D. Unilateral hinged external fixator of the elbow in complex elbow injuries. Injury. 2004;35:1158-66.
  3. Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of pri- mary and secondary constraints. Clin Orthop Relat Res. 1991;265:187-95.
  4. Luo ZP , Niebur GL, An KN. Determination of the proximity tolerance for mea- surement of surface contact areas using a magnetic tracking device. J Biomech. 1996;29:367-72.
  5. Milne AD, Chess DG, Johnson JA, King GJ. Accuracy of an electromagnetic tracking device: a study of the optimal range and metal interference. J Biomech. 1996;29:791-3.
  6. Cheng SL, Morrey BF. Treatment of the mobile, painful arthritic elbow by dis- traction interposition arthroplasty. J Bone Joint Surg Br. 2000;82:233-8.
  7. Dunning CE, Zarzour ZD, Patterson SD, Johnson JA, King GJ. Ligamentous sta- bilizers against posterolateral rotatory instability of the elbow. J Bone Joint Surg Am. 2001;83:1823-8.
  8. Volkov MV, Oganesian OV. Restoration of function in the knee and elbow with a hinge-distractor apparatus. J Bone Joint Surg Am. 1975;57:591-600.
  9. Bottlang M, O'Rourke MR, Madey SM, Steyers CM, Marsh JL, Brown TD. Radio- graphic determinants of the elbow rotation axis: experimental identification and quantitative validation. J Orthop Res. 2000;18:821-8.
  10. Sekiya H, Neale PG, O'Driscoll SW, An KN, Morrey BF. An in vitro biomechani- cal study of a hinged external fixator applied to an unstable elbow. J Shoulder El- bow Surg. 2005;14:429-32.
  11. Madey SM, Bottlang M, Steyers CM, Marsh JL, Brown TD. Hinged external fix- ation of the elbow: optimal axis alignment to minimize motion resistance. J Or- thop Trauma. 2000;14:41-7.
  12. Fukuda Y, Takai S, Yoshino N, Murase K, Tsutsumi S, Ikeuchi K, Hirasawa Y. Impact load transmission of the knee joint-influence of leg alignment and the role of meniscus and articular cartilage. Clin Biomech (Bristol, Avon). 2000;15: 516-21.
  13. Radin EL, Swann DA, Paul IL, McGrath PJ. Factors influencing articular carti- lage wear in vitro. Arthritis Rheum. 1982;25:974-80.
  14. Lill H, Korner J, Rose T, Hepp P , Verheyden P , Josten C. Fracture-dislocations of the elbow joint-strategy for treatment and results. Arch Orthop Trauma Surg. 2001;121:31-7.
  15. Beckett KS, McConnell P , Lagopoulos M, Newman RJ. Variations in the normal anatomy of the collateral ligaments of the human elbow joint. J Anat. 2000;197 Pt 3:507-11.