Chapter 6 Assessment of Acute Knee Injuries

Transcription

1 Learning Outcomes Chapter 6 Assessment of Acute Knee Injuries After this lesson, you should be able to: describe the common forces that produce acute injuries describe the following components of injury assessment related to acute knee injuries mechanism of injury symptoms signs stress tests special tests describe the common acute knee injuries Forces Acting on the Knee to Produce Acute Injuries Compressive Tensile Shear Rotational History Location of pain Weight-bearing status Sounds or sensations Onset acute or chronic Previous knee injury 1

2 Location of Pain Location of Pain You must know your anatomy! bony landmarks origin & insertion of ligaments insertion sites of tendons joint lines location of other soft tissues ACL pain inside the knee PCL can mimic a gastroc strain Menisci joint lines Mechanism of Injury Mechanism of Injury Valgus force medial meniscus lateral meniscus Varus force LCL medial meniscus Hyperextension ACL femur forced posteriorly on the tibia PCL tibia forced posteriorly on the femur posterior joint capsule 2

3 Mechanism of Injury Mechanism of Injury Hyperflexion PCL tibia forced posteriorly on the femur ACL Landing on the flexed knee with the ankle plantarflexed PCL tibia forced posteriorly on the femur Mechanism of Injury Mechanism of Injury Rotational stress usually results in injury to multiple structures Internal rotation ACL LCL anteromedial capsule posteromedial capsule arcuate complex (posterolateral capsule) 3

4 Mechanism of Injury Sounds or Sensations External rotation ACL LCL PCL arcuate complex (posterolateral capsule) Pop or snap ACL tear patellar dislocation subluxation fx Clicking meniscus injury Sounds or Sensations Sounds or Sensations Locking true meniscus injury loose body psuedo quadriceps weakness patellofemoral syndrome Giving way with buckling ligamentous instability ACL, PCL, MCL, LCL without buckling quadriceps weakness patellofemoral syndrome 4

5 Inspection Inspection Swelling intracapsular effusion ACL (hemarthrosis) fx (femoral condyle, tibial plateau) meniscal tear extracapsular edema Discoloration Atrophy Alignment of femur on tibia genu valgum (knock knees) genu varum (bowlegs) genu recurvatum (hyperextension) Tibial tuberosity Palpation ROM Should include key bony and soft tissue structures Based on location of pain presence of swelling, discoloration Flexion Extension - 0 5

6 Stress Tests (Single Plane) Lachman s Test ACL Lachman s prone Lachman s anterior drawer Normal Knee Positive Test Lachman s Anterior Drawer Anterior Drawer Test Stress Tests (Single Plane) PCL posterior drawer Godfrey s posterior sag Normal Knee Positive Test Posterior Drawer Godfrey s Posterior Sag 6

7 Posterior Drawer Test Stress Tests (Single Plane) valgus LCL varus Normal Knee Positive Test Valgus Stress Test Full extension Medial joint capsule ACL, PCL flexion Valgus Stress Test Full extension Medial joint capsule ACL, PCL flexion 7

8 Varus Stress Test Stress Tests (Multiplanar) Full extension LCL lateral joint capsule IT band arcuate ligament complex ACL, PCL flexion LCL Rotational instability Slocum drawer test Crossover test Pivot shift Slocum Drawer Test Slocum Drawer Test (cont.) Foot externally rotated tests for anteromedial instability anteromedial capsule ACL posteromedial capsule Foot internally rotated tests for anterolateral instability LCL anterolateral capsule ACL posterolateral capsule IT band popliteus tendon 8

9 Pivot Shift Special Tests Anterolateral instability Meniscal Injury McMurray s Apley s compression Normal Positive Test Common Acute Knee Injuries Contusion Sprain Meniscal injury Strain Chondral lesion Fracture Dislocation Contusions to the Knee Signs Symptoms Stress tests Special tests 9

10 Meniscal Injuries Function of menisci? Meniscal Injuries Signs Symptoms Stress tests Special tests Meniscal Injuries Meniscal Injuries Flap tear 10

11 Meniscal Injuries Meniscal Injuries Meniscal Injuries Initial Management RICE refer to orthopedist Meniscal Injuries Surgical Management somewhat dependent on location and type of tear location red zone red-white zone white zone 11

12 Meniscal Injuries Surgical Management somewhat dependent on location and type of tear tear type Sprains to the Knee Joint capsule Medial (tibial) collateral (MCL) Lateral (fibular) collateral (LCL) Anterior cruciate (ACL) Posterior cruciate (PCL) Arcuate complex Anterior View Posterior View MCL Sprains Signs Symptoms MCL Sprains Initial Management PRICE reduce pain & swelling restore normal ROM strengthen muscles around the knee Stress tests Special tests 12

13 MCL Sprains Return to play must have normal ROM pain-free functional activities grade I 10 days to 2 weeks grade II 3 weeks grade III 5 weeks LCL Sprains Signs Symptoms Stress tests Special tests LCL Sprains Management similar to MCL sprains ACL Sprains Signs Symptoms Stress tests Special tests 13

14 ACL Sprains Initial management PRICE restore normal ROM reduce swelling strengthen muscles around the knee ACL Sprains Surgical management ACL reconstructive surgery ACL is replaced with a graft bone-patellar tendon-bone hamstring (semimembranosus gracilis tendons) allograft (cadaver) ACL Sprains Predisposing factors extrinsic intrinsic ACL Sprains Predisposing factors extrinsic to knee hyperpronation of foot weakness of posterior tibialis anterior pelvic tilt anteverted hips/internal rotation of tibia menstrual cycle muscle coordination (neural control) 14

15 ACL Sprains Predisposing factors intrinsic to knee small intercondylar notch genu recurvatum small ACL PCL Sprains Signs Symptoms Stress tests Special tests Rotational Knee Instabilities AMRI ALRI PMRI PLRI 15