Special tests of knee


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Special tests of knee

  1. 1. Special Tests of Knee Patellar Glide test Knee flexed 20-30o, quadriceps relaxed Patella divided into quadrants and displaced in medial and lateral directions to assess tightness of parapatellar structures Medial glide of 1 quadrant = tight lateral structures Patellar Tilt test Knee extended, quadriceps relaxed Examiner lifts lateral edge of patella from the lateral femoral condyle Tight lateral structures indicated in neutral or negative angle to the horizontal A-P drawer First inspect to determine if there is any posterior sagging (may get false positive anterior drawer in a knee that is really PCL deficient) Knee at 90o, do anterior drawer in neutral as well as 30o IR and 15o ER In ER, medial complex should become tight; abnormal laxity = injury to posteromedial corner In IR, lateral complex should tighten and in the normal knee reduce anterior drawer; abnormal laxity = injury to posterolateral corner The IR/ER part is called the Slocum test Lachman test Perform an anterior drawer test at 15 degrees of flexion The most sensitive test for ACL deficiency Flexion Rotation Drawer Test Anterior force is applied to the tibia in 15o of flexion, resulting in anterior subluxation as in the Lachman test With further knee flexion the tibia reduces beneath the femur with a clunk and internal rotation of the femur Pivot Shift 3 requisites: non functioning ACL, an intact medial complex and an intact iliotibial tract Foot held in internal rotation with one hand and the leg slightly abducted, the other hand is placed on the lateral side of the leg at the level of the fibular head Apply a valgus thrust to the leg and gently flex it
  2. 2. If positive, subluxation will reduce at 20-30o with the lateral femoral condyle sliding forward on the tibial plateau to a reduced position Jerk Test Start with the knee flexed and apply a valgus and IR force to sublux the lateral tibial condyle anteriorly As the knee is extended the tibia reduces with a clunk Quadriceps Active Test Patient supine, knee flexed to 90o, foot flat on the table In the PCL deficient knee, tibia assumes a resting position posterior to normal Quadriceps contraction against resistance produces anterior tibial translation Dynamic Posterior Shift Test Leg positioned with the hip at 90o flexion and knee is slowly extended from 90o of flexion; Tibia is in a posteriorly subluxed position In PCL insufficiency, as the knee extends, suddenly reduces with a clunk Posteromedial Pivot Shift Elicited by flexing the knee more than 45 degrees, while applying a varus stress, compression and IR As the knee is brought into extension, the tibia suddenly reduces, ~ 20-40 degrees short of full extension To be positive, PCL, MCL and posterior oblique ligament should be divided External Rotation Recurvatum Test Patient being supine, lift the legs by the great toe Positive, when knee falls into varus hyperextension and tibial ER Hughston stated this test to be specific for injury to the arcuate complex (LCL, arcuate ligament, popliteus, lateral gastrocnemius) Insall believes that the test will be mildly positive with isolated injury to the posterolateral corner, but for excessive hyperextension and varus to be present, ACL must be torn and possibly the PCL too Posterolateral Drawer Test Perform posterior drawer test, with knee at 90o flexion and foot 15o ER If positive, lateral tibial plateau moves posteriorly on the femoral condyle; in contrast, the medial condyle does not move When asymmetrical = pathological ER of tibia
  3. 3. When the posterolateral structures are sectioned, ER of tibia increases ~5o at 90o of flexion When the PCL is torn, ER at 90o flexion increases another 15o ,if this test grossly positive, PCL is probably damaged Reverse Pivot Shift Test Elicited by bringing the knee from a position of 90o flexion, where it is subluxed, to the fully extended position under a valgus load and foot externally rotated, where it reduces Jakob test is grossly positive in 3% and weakly positive in 8% of normal knees This has been found to correlate with ligamentous laxity When the test is asymmetrical comparing to other side or reproduces symptoms, indicates posterolateral instability External Tibial Rotation Prone, knees at 30o and at 90o, foot is forcefully rotated externally The degree of rotation of the medial border of the foot is measured relative to the femur and compared with the contralateral side Palpate the tibial plateau to determine its relative position to the femoral condyles; this is to confirm that the increased ER is due to posterolateral instability rather than anteromedial instability There is considerable inter-individual variation in degree of maximal ER at 30o flexion: average 30o, range 15-45o .At 90o flexion: average 37o, range 15-70o Meniscal Tests Numerous rotation tests for meniscal pathology have been described All have the common purpose of trapping abnormally mobile or torn fragments of menisci between the joint surfaces, causing pain or clicking McMurray Test Intended to diagnose lesions of the posterior horn of the meniscus Patient supine, hip flexed 90o and knee flexed more than 90o For examining the right knee, the examiner stands to the patient's right side with left hand on the knee and right hand holding the foot The foot is taken from a position of abduction and ER to one of adduction and IR This is repeated for various angles between full flexion and 90o ,trapping of damaged meniscus is felt as a clunk by the fingers on the joint line
  4. 4. Imaging tests X-ray. Your doctor may first recommend having an X-ray, which can help detect bone fractures and degenerative joint disease. Computerized tomography (CT) scan. CT scanners combine X-rays taken from many different angles, to create cross-sectional images of the inside of your body. CT scans can help diagnose bone problems and detect loose bodies. Ultrasound. This technology uses sound waves to produce real-time images of the soft tissue structures within and around your knee, and how they are working. Your doctor may want to maneuver your knee into different positions during the ultrasound, to check for specific problems. Magnetic resonance imaging. MRI uses radio waves and a powerful magnet to create 3D images of the inside of your knee. This test is particularly useful in revealing injuries to soft tissues such as ligaments, tendons, cartilage and muscles. Surgery If you have an injury that may require surgery, it's usually not necessary to have the operation immediately. Before making any decision, consider the pros and cons of both nonsurgical rehabilitation and surgical reconstruction in relation to what's most important to you. If you choose to have surgery, your options may include: Arthroscopic surgery. Depending on your injury, your doctor may be able to examine and repair your joint damage using a fiber-optic camera and long, narrow tools inserted through just a few small incisions around your knee. Arthroscopy may be used to remove loose bodies from your knee joint, remove or repair damaged cartilage, and reconstruct torn ligaments. Partial knee replacement surgery. In this procedure (unicompartmental arthroplasty), your surgeon replaces only the most damaged portion of your knee with parts made of metal and plastic. The surgery can usually be performed with a small incision, and your hospital stay is typically just one night. You're also likely to heal more quickly than you are with surgery to replace your entire knee. Total knee replacement. In this procedure, your surgeon cuts away damaged bone and cartilage from your thighbone, shinbone and kneecap, and replaces it with an artificial joint made of metal alloys, high-grade plastics and polymers.