Internal_derangements_of_Knee.pptx in orthopaedics

Internal derangements of knee joint

1. INTERNAL DERANGEMENTS OF KNEE By- Dr. Lokendra Assistant professor (Orthopaedics) AIIMS Bathinda

2. Internal derangements of knee (IDK) It is a term used to cover the diseases involving disruption of the normal functioning of the ligaments or menscii of the knee joints. The commonest derangement is Medial collateral ligament injury followed by medial meniscus and ACL.

3. ANATOMY OF KNEE JOINT It is the largest joint of the body. It is a synovial hinge type joint. Mainly articulation of four bones:femur,tibia,patella and fibula. The primary articulation is between the condyles of femur and tibia.

4. LIGAMENTS Two major ligaments (inside knee joint) -Anterior and posterior cruciate ligament Two other ligament (outside knee joint) -Medial and lateral collateral ligament -They act to stabilise knee sideways motion.

5. Anterior cruciate ligament(ACL) Origin at the medial wall of the lateral femoral condyle and inserts into the middle of the intercondylar area. It have four main functions -Restrains anterior translation of tibia. -Prevent hyperextension of knee. -Acts as secondary stabiliser to valgus stress test. -Controls rotation of tibia on femur.

6. Examination of ACL Anterior Drawer Test With the knee flexed to 90deg, verification of relaxation of hamstrings.With foot stabilised and in neutral rotation, a firm gentle grip on proximal tibia is achieved. An anterior force is applied to proximal tibia with gentle to and fro motion to assess for increased translation as compared to C/l knee. %mm is the upper limit of anterior tibial displacement normally.

7. Lachmans test One hand secures and stabilises the distal femur while the other hand grasps the proximal tibia. A gentle anterior translation force is applied to proximal tibia. There is significant translation of tibia on the femur in an ACL deficient knee.

8. Patient rotated 20deg from supine towards the affected side. with slight distal traction on the leg, a valgus and internal rotation force is applied to the extended knee. With maintainence of force noted above, the knee is flexed past 30deg. Pivot shift in an ACL deficient knee, in the initial stages of knee flexion, the tibia will be anterolaterally subluxed on the distal femur with application of valgus and internal rotation at the knee. With further flexion of knee (past 30deg) the illiotibial band goes from an extendor to flexor of knee and tibial anterolateral subluxation reduces bak in place. Pivot Shift test

9. Posterior cruciate Ligament (PCL) -Originates from the anterolateral aspect of the medial femoral condyle within the notch and inserts along the posterior aspect of the tibial plateau, approximately 1 cm distal to the joint line. -Functions Provide restraint against hyperextension. Against posteior displacement of the tibia in flexed knee

10. Examination Posterior Drawer Test -With knee flexed to approx 90deg,foot in neutral rotation and stabilised, a firm but gentle posterior translation force is applied to proximal tibia. -Application of posterior translation force results in posterior subluxation of tibia on the femur in patient with PCL deficient knee.

11. Tibial Back drop Test In this test, we compare the prominences of proximal tibia to the femoral condykles with the knee flexed to 80deg. In a PCL deficient knee, the knee will be posteriorly subluxed due to gravity.

12. Medial Collateral Ligament(MCL) Arises from posterior aspect of medial femoral condyle and inserts to metaphyseal region of tibia 4-5cm distal to joint. Provides primary restraints to valgus stress at the knee. Examination- Valgus stress test - Opening of 5-8mm compared to other knee indicate complete tear.

13. Valgus stress test

14. Lateral Collateral Ligament(LCL) LCL originates on the lateral epicondyle of the femur and inserts on the fibular head. LCL is primary restraint to varus angulation and resist internal rotation forces. Examination- Varus stress test- Significant instability in full extension indicate complete LCL tear.

15. Varus Stress test

16. MENISCI Meniscus are C-shaped fibrocartilaginous structures. Two in number Medial and lateral meniscus They act as shock absorbers and also help in spreading weight. A meniscus is frequently torn at the same time as ACL tears during injury.

17. Examination Joint Line tenderness- It is an accurate clinical sign occuring in 75-85% of patients Effusion- present in approx 50% cases. Range of motion- Restricted by pain and swelling.

18. Mc Murray test This maneuver usually elicits pain or a reproducible click in the presence of a meniscal tear The Medial meniscus is evaluated by extending the fully flexed knee with foot/tibia internally rotated while a varus stress is applied. The Lateral meniscus is evaluated by extending the knee from the fully flexed position, with the foot/tibia externally rotated while a valgus stress is applied to the knee.

19. Apley Test Patient lie prone and knee flexed 90deg. An axial load is applied through the heel as the lower leg is internally and externally rotated. This grinding maneuver is suggestive of meniscal pathology if pain is elicited at the medial or lateral joint.

20. Physical trauma- Sports injury, RTA, Occupational stress. Patients with generalised ligamentenous disorders. Familial predisposition Genu Recurvatum Predisposing factors

21. Mode of injury MCL injury - Forced valgus stress. LCL injury - Forced varus stress. ACL- Forced Valgus in fully extended knee. PCL- High velocity Trauma with posterior dislocation of tibia in a flexed knee. Meniscus tear- Rotational stresses in flexed knees.

22. Imaging Modalities Xray- To rule out Bony injuries. MRI Arthroscopy- It is diagnostic as well as theraputic.

23. Treatment Protocols Choice of Treatment depends on 3 major factors: -Age -Functional disability -Functional requirement Treatment varies according to the ligament/cartilage injured. - It can be Conservative (Non Operative) and Operative.

24. NON OPERATIVE RX Methods Progressive physical therapy and rehabilitation Educating the patient how to prevent knee instability. Use of Hinged knee brace. Indications Isolated tears wtih no symptoms When growth plates are still open(children) People who do light work.

25. OPERATIVE RX Indications Patients with knee instability, pain or swelling. Progressive premature degenerative changes in patient with unstable knee Methods Repair Reconstruction Debridement and removal

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