Intraoperative Assessment of Mid-Flexion Instability in Primary Total Knee Replacement
Keywords:
Knee, Midflexion instabilityAbstract
Introduction: Midflexion instability in primary total knee replacement (TKR) is an evolving concept. Successful treatment of instability requires an understanding of the different types of instability.
Methods: A literature review was performed to identify information pertinent to midflexion instability in primary total knee replacement, utilising some guidelines.
Results: Three factors, i.e., elevated joint line, multiradii femoral component and medial collateral ligament (MCL) laxity, were identified to influence midflexion instability. Literature suggested mediolateral instability at 30–60° of flexion as diagnostic of midflexion instability. Literature search also revealed paucity in clinical studies analysing midflexion instability. Most of the evidence was obtained from cadaveric studies for elevated joint line and MCL laxity. Clinical studies on multiradii femoral component were limited by their small study size and early followup period.
Conclusion: Elevated joint line, multiradii femoral component and MCL laxity have been suggested to cause midflexion laxity in primary TKR. Due to limitations in available evidence, this review was unable to raise the strength of overall evidence. Future well-designed clinical studies are essential to make definitive conclusions. This review serves as a baseline for future researchers and creates awareness for routine assessment of midflexion instability in primary total knee replacement.
References
2. Vince KG, Abdeen A, Sugimori T. The unstable total knee arthroplasty: causes and cures. J Arthroplasty 2006 Jun;21(suppl1):44–49.
3. Vince K, Malo M. Instability in Total Knee Arthroplasty. In: Berry P, Trousdale and Dennis (eds)., Revision Total Hip and Knee Arthroplasty. Philadelphia, Lippincott, Williams and Wilkins; 2006.
4. Vince KG, ed. The unstable TKA: You rock, it rolls. Seminars in Arthroplasty. Elsevier; 2014 Sep;25(3).
5. Vince K. Flexion Instability: Mind the gap. Bone Joint J 2014;96-B(suppl12):63.
6. Schwab JH, Haidukewych GJ, Hanssen AD, Jacofsky DJ, Pagnano MW. Flexion instability without dislocation after posterior stabilized total knees. Clin Orthop Relat Res 2005;440:96–100.
7. Pagnano MW, Hanssen AD, Lewallen DG, Stuart MJ. Flexion instability after primary posterior cruciate retaining total knee arthroplasty. Clin Orthop Relat Res 1998;356:39–46.
8. Vince K. Extensor mechanism disruption after total knee arthroplasty. In: Insall, Scott, eds. Surgery of the Knee. fifth ed, Philadelphia, Elsevier- Churchill Livingstone;2011:1386–1410.
9. Abdel MP, Pulido L, Severson EP, Hanssen AD. Stepwise surgical correction of instability in flexion after total knee replacement. Bone Joint J 2014;96-B:1644–1648.
10. Martin JW, Whiteside LA. The influence of joint line position on knee stability after condylar knee arthroplasty. Clin Orthop Relat Res 1990;259:146–156.
11. König C, Matziolis G, Sharenkov A, et al. Collateral ligament length change patterns after joint line elevation may not explain midflexion instability following TKA. Med Eng Phys 2011;33:1303–1308.
12. McPherson EJ, Cuckler J, Lombardi AV. Midflexion instability in revision total knee arthroplasty. Surg Technol Int 2008;17:249–252.
13. Hino K, Ishimaru M, Iseki Y, et al. Mid-flexion laxity is greater after posterior-stabilised total knee replacement than with cruciate-retaining procedures: a computer navigation study. Bone Joint J 2013;95-B:493–497. Grood ES, Noyes FR, Butler DL, Suntay WJ. Ligamentous and capsular restraints preventing straight medial and lateral laxity in intact human cadaver knees. J Bone Joint Surg [Am] 1981;63-A:1257–1269.
14. Shoemaker SC, Markolf KL, Finerman GA. In vitro stability of the implanted total condylar prosthesis. Effects of joint load and of sectioning the posterior cruciate ligament. J Bone Joint Surg [Am] 1982;64-A:1201–1213.