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Arthroscopy of the Knee Joint: - Wheeless' Textbook of Orthopaedics
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Wheeless' Textbook of Orthopaedics

Arthroscopy of the Knee Joint:

 - See: Knee Joint Menu

- Discussion:
    - arthroscopy of the arthritic knee 
    - Arthroscopy following TKR 
    - chondral and osteochondral injuries of the knee
    - meniscal tears:
         - prevalence of wrong pre-operative diagnosis or additional pathology:
               - always consider an alternative diagnosis especially in younger patients (in whom bone tumors should be considered);
               - " isolated medial meniscal tear"
                       - actually occurs only 21% of time;
                       - additional dx in 23%;
                       - lateral meniscal tear 5% of time (referred pain)
                       - in 70% of ACL tears, there will be a meniscus tear;

- Preparation and Anesthesia

 - Portals:
    - anteroloateral portal
    - superomedial portal 
    - medial portals
    - superolateral portal:
            - useful viewing dynamics of patellofemoral articulation.
            - portal located just lateral to the quadriceps tendon about 2.5 cm superior to the superolateral corner of the patella;
            - in addition to the skin incision, the knife should nick the deep fascia to facilitate portal insertion;

    - reference:
            - Posterior portals for arthroscopic surgery of the knee

- Patellofemoral Joint:
    - see: chondromalacia and osteochondral lesions);
    - it is important to visualize the entire lateral and medial patellar facets (including the odd facet at the medial aspect of the medial facet);
    - normal patellar position in the extended knee is slightly lateral to the lateral femoral condyle, patella moving medially and distally w/ increasing flexion;
           - increasing contact occurs between lateral patellar facet & lateral femoral condyle;
           - most often patella seats in the center of trochlea at about 45 deg of flexion (and w/ suspected patellar subluxation, it is important to document the amount of knee flexion that elicits patellar contact and full patellar seating);
    - any plans for a lateral retinacular release should be delayed until the arthroscopy is completed, since bleeding from this procedure will interfere with visualization; 
    - Supra-patellar Pouch:
           - most often affected by inflammatory arthritis (w/ hypertrophic synovium);
           - medial synovial plicae 
    - reference:
           - Arthroscopic examination of the patellofemoral joint using a central, one-portal technique.  


- Medial Compartment: 
    - chondral injuries of the knee
          - these lesions are identified by flexing the knee to 45 deg;
    - visualization of the medial meniscus
          - begin by flexing the knee and holding the tibia in external rotation;
          - while holding external rotation, apply valgus, and extend the leg to between 10-30 deg;
                - note that an ACL deficient will tend to pivot w/ valgus stress, which brings the tibia forward thus imparing visualization of the posterior compartment;
                       - solution is to firmly hold the tibia in external rotation, which prevents the tibia from  subluxing forward;
                - gently titrate flexion and extension to give the best visualization of the posterior meniscal horn;
          - in difficult cases, an assitant can ballott both the medial and lateral menisci which can facilitate visualization and menisectomy;
                - if an assistant is not available a spinal needle can be inserted into the posteror medial aspect of the joint to hold the meniscus in a anterior position;
    - references:
          - Arthoscopic visual field mapping at the periphery of the medial meniscus: a comparison of different portal approaches
          - Evaluation of arthrography and arthroscopy for lesions of the posteromedial corner of the knee

- Intercondylar Notch:
    - ACL
    - PCL
    - for optimal assessment of the intercondylar notch, the surgeon should strive for the widest  panoramic view that is possible w/ the 30 deg scope directed laterally;
           - often the ligamentum mucosum will have to be taken down inorder to improve visualization;
           - if the fat pad appear to be in the way, then try a quick "push - pull" with the arthroscope inorder to pull the fat pad backwards;
           - if the fat pad continues to obstruct visualization of the notch, it will need to be partially shaved away;
                  - extend the knee and begin shaving above the intercondylar notch, and then work inferiorly;
                  - this method allows good visualization as the fat pad is being shaved;
           - fat pad syndrome or Hoffa's disease may be diagnosed arthroscopically when there is hypertrophic intercondylar/or infrapatellar synovitis extending to central to the inner rim of the anterior horn of the meniscus;
           - references:
                  - Hoffa's disease: arthroscopic resection of the infrapatellar fat pad.  
                  - Impingement of infrapatellar fat pad (Hoffa's disease): results of high-portal arthroscopic resection.

    - posteromedial drive through:
           - a required part of any knee arthroscopy is the posteromedial drive thru;
           - the scope is slid along the lateral side of the medial femoral condyle (under the PCL) until it reaches the posterior compartment;
           - in cases of large posterior horn tears (or displaced bucket handle tears), the torn portion of the meniscus may flip up into the posterior compartment;
                  - this portion of the meniscus will not been seen from the medial compartment;
           - reference:
                  - Arthroscopic examination of the posteromedial compartment of the knee joint.  

- Lateral Compartment:
    - visualization of lateral compartment
    - lateral meniscus 
    - popliteus tendon:
         - this tendon, arises from distal part of lateral femoral condyle just anterior to origin of the lateral collateral ligament;

- Complications of Arthroscopy:
    - infection:
         - note that there are several different methods of sterilizing arthroscopic instruments, and that some are better than others; 
         - references:
                - Septic arthritis following arthroscopic meniscus repair: a cluster of three cases.
                - Septic arthritis following arthroscopy: Clinical syndromes and analysis of risk factors.  
    - vascular and nerve injury
         - neural disruption / neuropraxia - is usually secondary to prolonged tourniquet times;
    - neurologic complications 
         - references:
               - Current Concepts Review.  Neurological Complications Due to Arthroscopy.
               - Injury to infrapatellar branch of saphenous nerve in arthroscopic knee surgery
    - synovitis
    - persistent drainage
    - effusions are common 
    - hemarthrosis 
    - iatrogenic fracture
           - references:
                - Supracondylar femoral fracture after anterior cruciate ligament reconstruction with transfemoral fixation.       
                - Extra articular arthroscopic release in post-traumatic stiff knees: a prospective study of endoscopic quadriceps and patellar release.
                - Serious consequences of the wrong diagnosis of meniscal lesion in a case of stress fracture of the distal femur. 
                - COMPLICATIONS OF KNEE SURGERY
                - Complications in Arthroscopic Surgery Performed by Experienced Arthroscopists.  
                - Supracondylar femoral fracture after arthroscopic reconstruction of the anterior cruciate ligament. A case report
                - Knee surgery: complications, pitfalls, and salvage
 
    - deep venous thrombosis
           - in the report by Wirth T, et al., in order to evaluate the risk of VTE in knee arthroscopy patients inorder to determine efficacy and safety of a low-molecular weight heparin (LMWH) (reviparin sodium) in preventing VTE.
           - there were 262 patients undergoing elective knee arthroscopy prospectively randomized to receive either no treatment or reviparin once daily subcutaneously for 7 to 10 days.
           - 239 patients were evaluable (122 no treatment, 117 receiving LMWH). 6 DVT were detected - 5 in  control group (5/117 - 4.1%) and only one in the active treatment group (1/116 - 0.85%). 
           - 1 patient had a transitory fall in platelet count below 100 giga-particles/L without any clinical symptoms.
           - patients undergoing knee arthroscopy have a moderate risk of VTE and effective prophylaxis can be achieved with LMWH (reviparin).
           - references:
                 - Prevention of venous thromboembolism after knee arthroscopy with low-molecular weight heparin (Reviparin).  Results of a randomized controlled trial 
                 - Incidence of Symptomatic Venous Thromboembolism After Elective Knee Arthroscopy

 Increasing the Osmolarity of Joint Irrigation Solutions May Avoid Injury to Cartilage: A Pilot Study

 

Alternatives to Total Knee Replacement:   Autologous Hamstring Resurfacing Arthroplasty




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, January 11, 2013 1:34 pm