The Use of Rotating Hinges in Unstable Total Knee Arthroplasty

James L. Howard M.D., MSc, FRCSC
London, ON

Instability is an important cause of failure following total knee arthroplasty. Recent literature has identified that instability is one of the most common reasons for revision total knee arthroplasty, accounting for approximately 25% of all revision cases3,12.

The goal of any revision knee arthroplasty is the creation of a functional and durable construct for the patient. Achieving this goal requires reconstruction of bony defects, correction of limb alignment, and stable fixation of the components to the host bone.

In the case of an unstable total knee arthroplasty, restoration of knee stability is critical. This must begin with a careful preoperative assessment of stability to determine what degree of constraint may be required at the time of revision. Ultimately, the choice of implant will be finalized at the time of revision after an intra-operative evaluation of the adequacy of available soft tissues and of ligament balance. Therefore, a full complement of component-constraint options must be available at the time of surgery.

Indications for the use of a rotating hinge when revising an unstable total knee arthroplasty include: absence of medial collateral soft tissue support, massive bone loss of the tibia or femur such that the collateral ligament origin or insertion is compromised, and severe residual flexion extension gap imbalance1,9. Other potential indications include: 1) comminuted distal femoral fractures in elderly low demand patients, 2) certain distal femoral non-unions or malunions, and, 3) in the setting of extensor mechanism disruption requiring reconstruction in the unstable knee1.

The clinical results of hinged knee replacements in revision total knee arthroplasty have been variable and dependent on prosthesis design. Early designs of hinged total knees generally did not fare well and had poor results. Reports on these early designs have demonstrated a number of problems including high rates of loosening, infection, and extensor mechanism problems2,4-6,8. High failure rates with early hinged knee designs were partially due to a true fixed hinge that only allowed motion in one plane of flexion and extension, without allowing varus or valgus tilt, axial rotation, or distraction. This resulted in high stresses on the hinge and excessive transmission of forces to the bone cement interface.

The rotating hinge design was conceived to improve outcomes compared to fixed hinge devices. Unfortunately, long-term studies on the early rotating hinge designs continued to show disappointing results with poor outcomes11,15. Subsequent hinged knee replacements attempted to address design flaws of the earlier generation implants. Barrack1 evaluated patients who underwent revision TKA with such a second generation implant. This design had improvements in the patellofemoral articulation, the mobile-bearing tibial component articulation and the rotating hinge mechanism, with the addition of modular canal filling slotted fluted stems and metaphyseal sleeves. He reported clinical results comparable to a large group of standard condylar revision total knees performed in the same time period with less challenging cases. Similar promising mid-term results have been reported by others with different rotating hinge designs7,16. Unfortunately, these encouraging reports may lead some surgeons to overuse these implants in situations where lesser amounts of constraint would be sufficient10. This concern has been addressed by several authors who have demonstrated that the use of rotating hinges is still associated with a significant complication rate even in the most experienced hands10,13,14. Nevertheless, rotating hinges will continue to have a role in treatment of the unstable knee, particularly in situations where a varus-valgus constrained design cannot be expected to maintain stability in the long-term9.

Therefore, when faced with the unstable total knee arthroplasty, the surgeon must carefully evaluate the status of the patient's bony and soft tissue elements to choose the amount of implant constraint required for the clinical situation. Although promising results have been reported with modern rotating hinge designs, complication rates are still significant. Hinged total knee arthroplasty should be reserved as the final salvage option when lesser amounts of constraint will not suffice to stabilize the knee.

References

  1. Barrack, R. L.: Evolution of the rotating hinge for complex total knee arthroplasty. Clin Orthop Relat Res, (392): 292-9, 2001.
  2. Cameron, H. U.; Hu, C.; and Vyamont, D.: Hinge total knee replacement revisited. Can J Surg, 40(4): 278-83, 1997.
  3. Fehring, T. K.; Odum, S.; Griffin, W. L.; Mason, J. B.; and Nadaud, M.: Early failures in total knee arthroplasty. Clin Orthop Relat Res, (392): 315-8, 2001.
  4. Hui, F. C., and Fitzgerald, R. H., Jr.: Hinged total knee arthroplasty. J Bone Joint Surg Am, 62(4): 513-9, 1980.
  5. Inglis, A. E., and Walker, P. S.: Revision of failed knee replacements using fixed-axis hinges. J Bone Joint Surg Br, 73(5): 757-61, 1991.
  6. Jones, E. C.; Insall, J. N.; Inglis, A. E.; and Ranawat, C. S.: GUEPAR knee arthroplasty results and late complications. Clin Orthop Relat Res, (140): 145-52, 1979.
  7. Jones, R. E.: Total knee arthroplasty with modular rotating-platform hinge. Orthopedics, 29(9 Suppl): S80-2, 2006.
  8. Karpinski, M. R., and Grimer, R. J.: Hinged knee replacement in revision arthroplasty. Clin Orthop Relat Res, (220): 185-91, 1987.
  9. McAuley, J. P., and Engh, G. A.: Constraint in total knee arthroplasty: when and what? J Arthroplasty, 18(3 Suppl 1): 51-4, 2003.
  10. Pour, A. E.; Parvizi, J.; Slenker, N.; Purtill, J. J.; and Sharkey, P. F.: Rotating hinged total knee replacement: use with caution. J Bone Joint Surg Am, 89(8): 1735-41, 2007.
  11. Rand, J. A.; Chao, E. Y.; and Stauffer, R. N.: Kinematic rotating-hinge total knee arthroplasty. J Bone Joint Surg Am, 69(4): 489-97, 1987.
  12. Sharkey, P. F.; Hozack, W. J.; Rothman, R. H.; Shastri, S.; and Jacoby, S. M.: Insall Award paper. Why are total knee arthroplasties failing today? Clin Orthop Relat Res, (404): 7-13, 2002.
  13. Springer, B. D.; Hanssen, A. D.; Sim, F. H.; and Lewallen, D. G.: The kinematic rotating hinge prosthesis for complex knee arthroplasty. Clin Orthop Relat Res, (392): 283-91, 2001.
  14. Springer, B. D.; Sim, F. H.; Hanssen, A. D.; and Lewallen, D. G.: The modular segmental kinematic rotating hinge for nonneoplastic limb salvage. Clin Orthop Relat Res, (421): 181-7, 2004.
  15. Walker, P. S.; Emerson, R.; Potter, T.; Scott, R.; Thomas, W. H.; and Turner, R. H.: The kinematic rotating hinge: biomechanics and clinical application. Orthop Clin North Am, 13(1): 187-99, 1982.
  16. Westrich, G. H.; Mollano, A. V.; Sculco, T. P.; Buly, R. L.; Laskin, R. S.; and Windsor, R.: Rotating hinge total knee arthroplasty in severly affected knees. Clin Orthop Relat Res, (379): 195-208, 2000.

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