Knee

What are the motions at the knee?

- Flexion and extension in SP - Some motion in TP due to condyles and meniscal anatomy - FP motion is pathological

What is the range of motion of the knee?

0 degrees extension 140 degrees flexion

what are the structures that resist varus stress valgus stress

1. LCL 2. PCL 3. IT band 4. ACL 1. MCL 2. oblique popliteal ligament 3. Cruciate ligaments

ACL and meniscal involvement (acute vs. chronic)

About half of all patients with an ACL injury also have a torn meniscus. A lateral meniscus tear occurs more commonly with an acutely torn ACL. These are usually vertical tears in the posterior horn. Chronic ACL tears are usually associated with medial meniscus tears. These meniscus tears are often classified as oblique, horizontal, radial, flap, undersurface, degenerative, bucket-handle, or displaced.

Normal hip ROM

Add 20, Abd 40, Flexion 120, Extension 20, Med/lat rotation 45 (varies between individuals)

ACL MOI

An ACL tear usually occurs with: (1) low-velocity, non-contact, deceleration injury, like landing from a jump or (2) a contact or collision knee injury with a rotational component, twisting, bending, and hyperextension. ACL injury can occur from seemingly simple activities.

Describe 2 unique characteristics of both or either meniscus:

Both menisci have coronary ligaments and transverse ligaments and they both move posteriorly during flexion and anteriorly during extension. The medial meniscus is connected to the ACL and the MCL (TCL).

True or False: Cartilage is the major shock absorber in the knee?

False premise behind treating osteoarthritis (OA) of the knee is that the major shock absorbing mechanism of the knee is not the cartilage but the muscle. The muscle absorbs 80 percent of the shock. The basis of our program is to get the muscle to a strength level to be able to absorb enough shock so that the patient no longer has pain

where is the AOR in the knee

Femoral condyles (medial to lateral)

Your patient has genu varus at the knee. What are the likely biomechanical and clinical consequences?

Genu varus is when the knees are bowlegged and is caused by coax valgas. Biomechanically it results in an increased load on the medial compartment of the knee. There will be increased compression medially but increased tension laterally

Knee OA: describe possible interventions

If pain is the major cause of limitation, it is addressed first. If it is a small painful area, such as a pes anserine bursitis, iontophoresis is used. If the pain area is larger, electrical stimulation and/or ultrasound is used. We encourage patients to use ice (10 to 30 minutes) if it helps to reduce the pain symptoms. Capsaicin, a topical pain reliever, can also be recommended for temporary pain relief. http://physical-therapy.advanceweb.com/Article/Examining-Further-Treatment-for-Osteoarthritis.aspx

What is TP motion in the knee neccessary for?

In order to 'screw home' the knee in ext, caused by medial rotation of the femur into the larger medial condyle, stabilising the knee and tightening the collaterals

Where does the ACL run, and what role does it have?

Location - runs post and sup from ant aspect of tibial plateau to posterolateral aspect of intercondylar notch Role - prevents tibia moving forward on femur and controls rotational motion

explain the diffs between the femoral condyles

Medial - longer (even surface with lateral condyle due to medial inclination of femur) and more curved than the lateral both are convex in sagittal and frontal plane lateral trochlear groove is higher

How is a PCL injury diagnosed

Part of the diagnosis of a PCL tear is made by knowing how the injury happened. Knowing the story of the injury (for example, the position of the leg and the action taking place) will help in making the diagnosis. Specific maneuvers can test the function of the PCL. The most reliable is the posterior drawer test. With the knee bent, your doctor will push the tibia backwards; this stresses the PCL. If the PCL is deficient or torn, the tibia will slide too far backwards, and indicate an injury to the PCL. X-rays and MRIs are also helpful in clarifying the diagnosis and detecting any other structures of the knee that may be injured. It is common to find other ligament injuries or cartilage damage when a PCL tear is found. PCL tears are graded by the severity of injury, grade I through grade III. The grade is determined by the extent of laxity measured during your examination. In general, grading of the injury corresponds to the following: Grade I: Partial tears of the PCL. Grade II: Isolated, complete tear to the PCL. Grade III: Tear of the PCL with other associated ligament injury.

What role does the medial collateral ligament have? and where does it run?

Role - Provides medial stability Location - Originates from med condyle of femur to anteromedial aspect of tibia and med meniscu

What role does the med and lat menisci play? and where are they located?

Role - absorb forces, protect cartilage and aid in stabilisation, lubrication and nutrition of the knee Located - Intra articular attatchments to tibial plateau

What role does the lateral collateral ligament play? and where does it run?

Role - provides lateral stability Location - originates from lateral border of femur to head of fibula (cord like)

What force generally injures the menisci?

Rotational (torsion) forces - asssociated with a 'pop' sound when injured

What are the symptoms of a PCL injury?

The most common symptoms of a PCL tear are quite similar to the symptoms of an ACL tear. Knee pain, swelling, and decreased motion are common with both injuries. Patients may have a sensation that their knee "popped" or gave out. Problems with knee instability in the weeks and months following PCL injury are not as common as instability following an ACL tear. When patients have instability after a PCL injury they usually state that they can't "trust" their knee, or that it feels as though the knee may give out. If this complaint of instability is a problem after a PCL injury, it may be an indicator that surgery is recommended.

ACL Injury Symptoms

There may be an audible pop or crack at the time of injury. A feeling of initial instability, may be masked later by extensive swelling. A torn ACL is extremely painful, in particular immediately after sustaining the injury. Swelling of the knee, usually immediate and extensive, but can be minimal or delayed. Restricted movement, especially an inability to fully straighten the leg Possible widespread mild tenderness. Positive signs in the anterior drawer test and Lachman's test (see ACL injury assessment). Tenderness at the medial side of the joint which may indicate cartilage injury.

What stress causes injury to the medial collateral ligament?

Valgus stress

What stress causes injury to the lateral collateral ligament?

Varus stress

Your patient has chronic PCL tear and is seeing you for knee pain. What muscle group would you strengthen to provide dynamic stability to substitute for the loss of stability of a torn PCL?

You would want to strengthen the anterior and lateral knee extensors (the quads) PCL prevents posterior movement of the tibia so you would want to strengthen the quads

define the Q angle

angle between femur line and patella ligament to ASIS line -10-15 is normal -decreases with flexion (IR of tibia)

which way should you mobilize the tibia to increase knee extension

anterior

You are designing an exercise program for a patient with knee pain. You want to avoid exercises that demand a large external torque at the knee. Describe an exercise in both open and closed chain. a. Closed chain squats through the range of motion in standing (90-0 degrees) b. Open chain terminal knee extension exercise with the foot off the ground c. Open chain knee extension from 90 to 45 degrees flexion with the foot off the ground d. None of these exercises should ever be performed

c

How is the PCL injured

he most common mechanism of injury of the PCL is the so-called "dashboard injury." This occurs when the knee is bent, and an object forcefully strikes the shin backwards. It is called a 'dashboard injury' because this can be seen in car collisions when the shin forcefully strikes the dashboard. The other common mechanism of injury is a sports injury when an athlete falls on the front of their knee. In this injury, the knee is hyperflexed (bent all the way back), with the foot held pointing downwards. These types of injuries stress the PCL, and if the force is high enough, a PCL tear will result

Which structure at the knee is the primary restraint to a varus stress?

lcl

explain the diffs between the menisci

medial - larger both - flat, concave, shallow, coronary ligaments, aneural, more vascular in outer 1/3, move posterior in flexion and anterior in extension

what structures will be injured with a valgus force at the knee

valgus force is into knock knee - pushing knee inward -Anterior retinaculum -MCL -Semimembranosis -popliteal ligament

what structures will be injured with a varus force at the knee

varus force is into bow leg - pushing knee outward -anterior/lateral quad -IT band -PCL -LCL (FCL)