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Knee arthroscopy and partial medial menisectomy

    Overview

    Professional Guidelines Included
    Learn the Knee arthroscopy and partial medial menisectomy surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Knee arthroscopy and partial medial menisectomy surgical procedure.
    Arthroscopic partial meniscectomy is a commonly performed procedure. In recent years a clearer understanding of the success of meniscectomy in the degenerative knee has reduced its popularity, as non-operative treatment may result in greater patient satisfaction. However there is still strong evidence for its use for acute and/or unstable tears.
    Tears in the non-vascular “white-on-white” zone are not amenable to meniscal repair (see separate presentation) and therefore may require conservative debridement back to healthy stable meniscal tissue.
    The surgery is performed with the use of a combination of handheld instruments such as punches, shavers and more recently radio-frequency ablation.
    The detail in this technique in terms of the mechanics of performing a knee arthroscopy is complementary to knee arthroscopy also detailed on OrthOracle.
    The various OrthOracle techniques detailing techniques of meniscal repair can also be usefully read in conjunction with this technique: Trans-tibial meniscal root repair using Smith and Nephew Firstpass mini and Meniscal repair using Smith & Nephew fast-fix 360 system & knee arthroscopy.

    Indications

    INDICATIONS
    Arthroscopy
    Knee arthroscopy has evolved as the equipment has improved from a diagnostic procedure to a become a means by which to perform less-invasive procedures, with faster recovery and reduced morbidity. The following is a list of commonly performed procedures using an arthroscopic technique:
    meniscectomy
    meniscal repair
    loose body removal
    synovial biopsy / synovectomy
    ligament reconstruction (ACL / PCL)
    chondral stabilisation and regeneration procedures
    adjunct to periprosthetic trauma management e.g. tibial plateau fracture reconstruction
    Occasionally diagnostic procedures can be used for pre-planning for instance in the case of high tibial osteotomy, to carefully assess the joint surfaces. However with increasing definition of magnetic resonance images the need has reduced.
    Meniscectomy
    Meniscal tears can be categorised in many ways: site, type, shape, stability. However it is vital to appreciate from a management perspective to first understand if the tear is:
    acute – tear in an otherwise normal healthy meniscus, often caused by a significant injury
    degenerative – tear in degrading meniscal tissue – as described by the BASK Meniscal Working Group (July 2018)
    Unstable tears that are irreparable (see Meniscal repair presentation in OrthOracle) may be amenable to excision or debridement.
    SYMPTOMS & EXAMINATION
    Pain – the pain arising from a meniscal tear is often well localised to the joint line, activity-related and often sharp in nature. This is distinct from arthritic pain which is often a general dull ache, even at rest.
    Mechanical symptoms – true locking (jamming in flexion) and giving way are symptoms attributed to unstable meniscal tears. A locked knee will often indicate a large displaced bucket-handle type tear, which may be eminently repairable. In this clinical scenario the surgeon should consider urgent investigation and/or proceeding to urgent surgery for potential repair. Even if the meniscus is not repairable, removal of the displaced meniscal fragment will allow recovery of full extension. The risk of a permanent fixed flexion deformity increases with time, so surgery as advised as soon as possible within a 12 week window of the event.
    On examination the telltale signs include:
    swelling / effusion especially acutely
    point tenderness on the jointline
    pain on valgus (medial tear) or varus (lateral tear) stressing of the knee
    McMurray’s test – the knee is brought into deep flexion and, with the foot is grasped by the examiner, the knee is twisted into internal rotation (lateral tear) and external rotation (medial tear). A positive test elicits pain on rotation often with a palpable albeit subtle click
    Care must be taken to fully assess the knee for concomitant ligamentous injuries such as ACL tear.
    IMAGING
    X-ray – in an acute setting an x-ray can be useful to rule out a bony injury; in the more chronic cases a weight-bearing x-ray can help differentiate between a meniscal tear and osteoarthritis
    MRI – is the mainstay investigation – a tear is confirmed as a breach in the meniscal tissue (seen as a white line in T2 weighted images) that reaches the surface of the meniscus in at least two sequential slices.
    This modality is reported to have a >82-97% sensitivity of detecting meniscal tears, subsequently confirmed on arthroscopy (Sharifah et al. Knee Surg Sports Traumatol Arthrosc 2015 Mar;23(3):826-30). These figures correlate with our own audit. Note that there is higher sensitivity with lateral vs meniscal tears:
    medial meniscus – sensitivity 80%; specificity 75%; negative predictive value 75%; positive predictive value 80%
    lateral meniscus – sensitivity 92%; specificity 91%; negative predictive value 95%; positive predictive value 85%
    ALTERNATIVE OPERATIVE TREATMENT
    Meniscal repair if appropriate.
    See Meniscal repair using Smith & Nephew fast-fix 360 system & knee arthroscopy
    NON-OPERATIVE MANAGEMENT
    Non-operative management with pain relief and physiotherapy – this is particularly the case in chronic or degenerative tears
    CONTRAINDICATIONS
    Active infection

    Setup

    The patient is supine on the operating table.
    High thigh tourniquet
    Side support at the level of the tourniquet
    Antibiotics at induction (if meniscal repair is planned)
    Arthroscopy stack including:
    screen
    light source
    video and image capture computer
    pump for fluid set at 30-40mmHg to insufflate the knee (optional: some surgeons prefer not to use pumps but instead use gravity and a sterile bladder on the tubing to pump the fluid on demand)
    shaver / resection device
    radio-frequency ablation
    arthroscopic handheld instruments -ACUFEX punches: 1. curved-up 2. straight 3. curved-right 4. curved-left 5. left side-cutting 6. right side-cutting 7. arthroscopic grasper

    Operation

    This AP fat suppressed T2 MRI image shows a clear white line extending from the undersurface of the periphery of the meniscus into the body without extending to the capsular (red) zone, suggesting a white zone tear.

    Similarly the tear is visible as a white line on this lateral fat-supressed T2 weighted MRI image, extending from the inferior surface. To reiterate a tear is confirmed as a breach in the meniscal tissue (seen as a white line in T2 weighted images) that reaches the surface of the meniscus in at least two sequential slices.

    A curved side-support is placed at the level of the tourniquet, so that the caudal edge of the support lines up the the caudal edge of the tourniquet.A sandbag can be placed under the opposite buttock to minimise rotation of the operated leg during valgus stressing.

    The leg is prepared with alcoholic betadine. The arthroscopy drape is applied to expose the knee below the tourniquet and above the leg bag, to avoid water going into the leg bag.Ensure that the leg is free to move into deep flexion (pictured), full extension, valgus stress position against the side support and “figure-of-four” position.
    The wires and tubing should be fixed above the operative site at the level of the patient’s abdomen.
    The patella, patellar tendon and the medial and lateral joint lines are marked out. The lateral “viewing” portal is marked immediately lateral and half way up the tendon.

    A horizontal, lateral portal is first made with an 11 blade, its blunt edge turned towards the tendon to avoid inadvertent damage.The lateral “viewing” portal is marked immediately lateral and half way up the tendon.
    Portals can be made horizontal, vertical or oblique. I prefer a horizontal portal as this reduces the risk of damaging the anterior horn of the menisci.

    The cannula and blunt trocar are introduced pushing parallel with the tibial slope, towards the notch.This position is simply to introduce the blunt trocar and cannula and care should be taken not to advance it once the joint has been entered. Further advancement requires extension of the knee.

    The cannula and trocar are “swung” carefully under the patellar into the suprapatellar pouch whilst bringing the leg into extension.

    The tip of the cannula itself is sharp so the blunt trocar must be left in situ until safely in the pouch and insufflated with fluid. The trocar can then be replaced with the scope and camera.
    Diagnostic arthroscopy is performed using a 30 degree arthroscope. Angled scopes are required because the bony structure of the knee allows the arthroscope to be positioned only in certain positions. The angled scope allows the surgeon a greatly increased view within the joint. Rotating the scope will show a series of views angled at 30 degrees from the axis of the scope.
    Initially view the patellofemoral joint by turning the camera to look proximally. If formal assessment of patella tracking is required then this is best assessed viewing though a superolateral portal.

    After the patellofemoral compartment the medial compartment is viewed. The ankle is rested on surgeon’s hip and forced into valgus against the side support to open this part of the joint.Slight (10-20 degrees) of flexion allows relaxation of the postero-medial structures of the knee and therefore improves medial opening.
    In very tight cases the medial collateral ligament (MCL) can be trephined with a green needle percutaneously to open up the gap. The tip of needle can divide 1-2mm width of MCL fibres, particular in the posterior half of the ligament, at joint level.

    This image shows the body of the medial meniscus.

    It is imperative to be able to see and assess the meniscus from the anterior horn, through the body to the posterior horn.Occasionally it is necessary to pass into the posterior aspect of the medial compartment through the notch, medial to the anterior cruciate ligament, which is the view shown in this image.
    This access and view is particularly important when dealing with ACL injuries. This is to look for a RAMP lesion, a menisco-capsular separation of the posterior horn of the medial meniscus.

    Once in the medial joint a medial portal is created under direct vision, its exact location determined by the surgical objective.The key is to make this portal with the knee in position at which the meniscectomy is to be undertaken, in this case in the near extended valgus position. Changing the knee’s orientation after making the portal will malalign the skin and capsular incisions and make passage of instruments more difficult.
    A needle is inserted through the antero-medial skin. In the case of a posterior third medial meniscal tear it must be remembered that the handheld instruments need to reach under the femoral condyle. Therefore the portal must be as low and midline as possible. The needle must therefore emerge 2mm above the menisco-capsular junction. This differs from the portal for a lateral meniscal tear which will need to be higher in order to pass over the tibial eminences. In the case of both medial and lateral meniscal tear the surgeon may choose to make the portal vertical to allow extension (as made under direct vision this reduces the risk of iatrogenic anterior horn injury).

    The needle is removed, noting its entry point and the 11 blade is inserted under direct vision to make the portal.
    The horizontal orientation reduces risk of damage to the meniscus and the articular surfaces. The blade is pushed into the knee. The shape of the blade cuts the portal as it goes deeper. The skin incision will be no more than 10mm in width.

    Once the medial portal is created an arthroscopy hook is used to identify the position, extent and nature of the tear.In this case it is short vertical tear of the body. It is imperative to identify the beginning and end of the tear in order to plan the meniscectomy without under- or overresecting. This is more difficult to assess with the punches, therefore take time with the hook.

    Once the most anterior aspect of the tear is identified the meniscectomy begins, in this case with a curved-left punch to create a curved rather than sharp resection edge.The resection continues into the tear but not beyond. If orientation becomes difficult then the punch can be removed and the tear reassessed with the hook.
    The resection can be continued with the handheld punches for a clean finish. The curved-up punch works well around the posterior third of the medial meniscus passing under the femoral condyle without damaging the articular surface.

    The options for further resection are:
    continue with handheld punches and using as grasper to remove the fragment
    remove piecemeal with the punches and use a shaver to remove the debris
    resect using the shaver
    All approaches as acceptable. I prefer to use the punches for as much of the resection as possible as it reduces the risk of overresection and inadvertent chondral injury. It also leaves a cleaner finish with reduce the risk of further tearing.

    The resected meniscus is reassessed with the hook to ensure it has been completely removed.

    Complete the diagnostic aspect of the arthroscopy, after medial menisectomy, with a view of the notch and assess both the ACL and PCL.

    Complete the diagnostic aspect of the arthroscopy by viewing the lateral compartment.The knee is fully flushed out to ensure that no loose fragments remain in the knee. As much saline is removed as possible. The portal may or may not be closed with removable sutures. In a relatively avascular procedure such as a white zone meniscal resection, which will not ooze significantly, I often leave the portals to heal without suture. These are dressed with a waterproof adhesive.
    The knee is bandages with wool and crêpe. The tourniquet is released.

    Post Operative

    The patient can fully weightbear as pain allows. Early mobilisation reduces the need for formal anti-DVT measures provided the patient does not have an increased risk.
    The wool and crêpe can be removed after 48 hours, but the waterproof adhesive needs to remain on covering the portals for 14 days.
    Return to sport should be delayed for 3-4 weeks at the earliest dependent on the reaction of the knee.
    Formal physiotherapy is often not required but swelling control, gait retraining, range, quads bulk and proprioceptive recovery are commenced immediately.

    Recommended Reading

    Arthroscopic surgery and especially meniscectomy has come under a great deal of scrutiny in recent times. This is driven by poor result of the surgical management of degenerative meniscal tears. As a consequence guidelines have been expertly developed by both European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) and the British Association of Surgery of the Knee (BASK), linked below. The ESSKA document in particular lists the review of current literature for both non-degenerative and degenerative tears.
    https://cdn.ymaws.com/www.esska.org/resource/resmgr/Docs/meniscus-consensus-project-p.pdf
    http://baskonline.com/professional/clinical-care/meniscal-surgery-guidelines/#1531380165416-89d240cf-0dd0
    The advancement of repair techniques impart a need on the treating clinician to recognise those acute tear that are amendable to salvage rather than resection.
    Philippe Beaufils, Roland Becker, Sebastian Kopf, Ollivier Matthieu, Nicolas Pujol. The knee meniscus: management of traumatic tears and degenerative lesions. EFORT Open Rev. 2017 May; 2(5): 195–203.
    This 2017 literature review article is available online. It describes the effects of menisectomy versus meniscal repair in both the stable knee and the unstable (ACL-deficient) knee. Salient points are:
    6% of acutely injured knee sustain an isolated meniscal tear; the rate of meniscal tear increases with an ACL injury
    risk of OA at 20 years post lateral meniscectomy is 56%
    meniscectomy in an ACL deficient knee will lead to OA in near 100% patients at 30 years
    meniscal repair in conjunction with ACL reconstruction not only has a higher rate of success of repair rates of 14% at 6 years (MOON study) but also protects the ACL graft be conferring improved stability
    there is strong evidence on support of primarily meniscal repair or indeed leaving a torn meniscus in situ versus early meniscectomy
    Fillingham YA, Riboh JC, Erickson BJ, Bach BR Jr, Yanke AB. Inside-Out Versus All-Inside Repair of Isolated Meniscal Tears: An Updated Systematic Review. Am J Sports Med. 2017 Jan;45(1):234-242.
    A review paper which showed that all-inside with modern devices produces the same results of success of repair, functional outcomes and complication rates as the gold standard inside-out techniques.

    Reference

    • orthoracle.com

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