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Risk Factors for Mid-Flexion Instability After Total Knee Arthroplasty: A Systematic Review.
Sravya P Vajapey1, Robert J Pettit1, Mengnai Li1
1Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH.
The Journal of Arthroplasty
|June 14, 2020
Summary
Mid-flexion instability after total knee arthroplasty (TKA) is a poorly understood issue. This review identifies patient, implant, and technique factors, noting inconclusive evidence for some and highlighting the importance of articular conformity and preoperative laxity.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
Background:
- Mid-flexion instability is a significant complication following total knee arthroplasty (TKA), often leading to patient dissatisfaction and poorer functional outcomes.
- This clinical entity remains understudied, necessitating a comprehensive review of its associated risk factors.
Purpose of the Study:
- To conduct a comprehensive literature review to identify and analyze risk factors contributing to mid-flexion instability after TKA.
- To synthesize current research findings on implant-related, technique-related, and patient-related factors influencing mid-flexion instability.
Main Methods:
- A systematic literature search was performed across major databases (PubMed, EMBASE, Google Scholar, Cochrane Library) for studies published between 2010 and 2020.
- Keywords included "mid flexion," "instability," and "knee arthroplasty." Studies were analyzed for research design, research question, and outcomes, with both quantitative and qualitative analyses conducted.
Main Results:
- Eighteen articles were reviewed, comprising computational, cadaveric, and clinical studies.
- Fourteen risk factors were identified: 6 implant-related, 6 technique-related, and 2 patient-related. Five factors showed contradictory results, leading to inconclusive associations.
- Articular surface conformity and preoperative joint laxity emerged as potentially more significant factors than previously recognized, while joint line elevation and femoral component radius of curvature effects were inconclusive.
Conclusions:
- Mid-flexion instability in TKA is a distinct clinical problem with identifiable patient, implant, and technique-related risk factors.
- Current evidence predominantly stems from computational and cadaveric research, highlighting a critical need for more extensive clinical investigations to validate these findings.
