Arthroscopic Management of Discoid Lateral Meniscus in the Pediatric Knee



Arthroscopic Management of Discoid Lateral Meniscus in the Pediatric Knee


Benton E. Heyworth



Operative Indications



  • Symptomatic lateral discoid meniscus



    • Symptoms may include lateral-sided knee pain or mechanical symptoms (clicking, clunking, snapping, popping, locking) which adversely affect a child’s gait (ie, limping), activities of daily life, sports, or participation in recreational activities (eg, free play, playground activities, gym class)


  • Lateral discoid meniscus tear



    • Even in the setting of minimal or no symptoms, the presence of a true tear within a discoid meniscus should warrant consideration of proactive surgical treatment, so as to remove the tear, “stabilize” the free edges of the meniscus, and prevent the tear from propagating or worsening. Progression of a small tear to a large, complex, or degenerative tear may preclude meniscal preservation and lead to the need for subtotal or total meniscectomy, after which an accelerated rate of arthritis may be predicted at a young age1,2,3,4


    • Radiologic assessment of a tear within a discoid meniscus can be more complex than that in a normal meniscus. Therefore, a higher resolution, higher quality (eg, 3 T magnet) magnetic resonance imaging (MRI) study may be helpful


    • One or more different tear patterns may be seen, including radial, vertical, horizontal, or complex/degenerative tears, as well as meniscocapsular separation or instability. Intermediate or high signal abnormality in the middle of a complete or near-complete discoid meniscus is not necessarily a horizontal cleavage tear, particularly if there is no extension of the signal abnormality to the central free edge or to the superior or inferior meniscal surface


    • If intrasubstance signal abnormality is detected in the absence of significant symptoms, and the shared decision-making process with a patient’s family results in a decision for nonoperative treatment, close observation or monitoring should be pursued, in the form of annual clinical checks and consideration of serial MRI studies


    • If there is worsening of the radiologic appearance, or if symptoms worsen, surgical treatment may allow for a more successful overall meniscal preservation strategy, though this has not been clearly established in the literature


    • While more prospective research is needed on the controversial topic of timing of discoid meniscus surgery, the author believes that a “wait and see” approach—in which surgery is deferred until symptoms become severe or functionally limiting or more definitive tear patterns are identified—may represent a suboptimal strategy, from a long-term joint preservation perspective




Positioning



  • Standard supine positioning



    • A lateral knee post is used on a standard operating room (OR) table to ensure adequate valgus stress for visualization of the medial compartment during the diagnostic arthroscopy portion of the procedure


    • Most of the surgery is performed with the knee in the figure-4 position (see Figure 35.2), in which the knee is flexed to 60° to 100° of flexion and the hip is externally rotated


    • Opening of the lateral compartment, to minimize the chance of iatrogenic injury to the lateral femoral condyle or tibial cartilage surfaces, is best achieved by placing the lateral aspect of the foot of the operative side on the anterior surface of the mid-tibia of the sterilely draped contralateral extremity, which allows the surgical technician or assistant to hold the foot in place (short arrow) in an optimal position (Figure 35.2)


    • Additional gapping of the lateral compartment can be achieved by simultaneously applying a downward force on the medial aspect of the knee


    • These two steps (securing the foot, varusizing the knee) may be performed selectively, only when sharp instruments are passed through the lateral compartment, so as to free the hands of the assistants for instrument passage and other functions








Surgical Approach

Jun 9, 2022 | Posted by in Reconstructive surgery | Comments Off on Arthroscopic Management of Discoid Lateral Meniscus in the Pediatric Knee
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