Knee Conditions and Interventions
PTA 104 Ortho Dysfunctions

Instructional Use Statement

The following information is used for instructional purposes for students enrolled in the Physical Therapist Assistant Program at Lane Community College. It is not intended for commercial use or distribution or commercial purposes. It is not intended to serve as medical advice or treatment.

Contact howardc@lanecc.edu for permissions

Lesson Objectives

1. Describe the role of ligaments, menisci, muscles, patellofemoral and tibial-femoral joints in knee motion
2. Identify common special tests for the knee that inform decision-making and care planning for the knee
3. Describe signs and symptoms of common selected knee dysfunctions encountered in the physical therapy practice
4. Distinguish interventions for knee conditions based on the rehabilitation/tissue healing stage
5. Given a knee case situation,
1. Recognize specific motion and joint precautions for non-operative and operative knee conditions
2. Identify relevant tests and measures needed to inform clinical decision-making
3. Select exercise and other interventions to address the impaired structure, function, or participation restriction
4. Recognize situations that require communication with the supervising physical therapist

Video Supports

Approximately 100 minutes of embedded videos are included as information to support meeting lesson objectives

 Intro Video From Christina - Approximately 15 minutes

Review of Knee Joint Function

Ligaments and menisci

• Tibiofemoral: primary motion is between the distal femur and proximal tibia is flexion and extension with accessory motion of internal and external rotation.
• Ligaments, menisci and the joint capsule are the primary static stabilizers
• LCL and MCL excessive motion laterally and medially, respectively (side-to-side)
• ACL and PCL control motion anterior and posteriorly, respectively (back and forth)
• Menisci distribute the weightbearing forces from the femur onto the tibia; wedge shape provide additional stability

• The medial meniscus is attached to: both cruciate ligaments, the medial collateral ligament, and the semimembranosus tendon. Any injury to these structures often creates a meniscal injury as well.
  

   

Muscles

Knee muscles function to produce movement and provide dynamic stability

• gastroc provides soft tissue resistance preventing hyperextension; secondary knee flexor
• popliteus muscle initiates open chain lateral tibal rotation to allow knee to flex from full extension
• pes anserine (gracilis, sartorius, semitendinosus) are medial stabilizers for tibia rotation in closed chain
• quadriceps, hamstrings, gastrocnemius produce motion and control motion at the knee
• peak quadriceps function occurs at 70-50 degrees of flexion and is nearly exhausted at 15 degrees of flexion ( hence extensor lags)
• The soleus assists with maintaining extension in standing.
• hamstring strength is greatest when it is stretched by hip flexion (common to 2 joint muscles) and poor hamstring function can cause genu recurvatum due to poor posterior  instability.
• the gastrocnemius can assist in protecting against hyperextension in closed chain activities.
• the pes anserinus group help with medial knee stability.In regard to the pes anserine, recall that one of the members is attached to medial collateral ligament and an injury to this ligament can cause some pain referrals and dysfunctions in all the muscles due to their common attachment. A helpful memory device about the order of attachment and palpation is Say Grace before Tea. This is important to remember because medial collateral ligaments are often managed conservatively, and due to the extensive attachments, it is difficult to treat all the possible sequelae.

Patellofemoral joint

Patellofemoral: lies anterior to the distal femur and articulates in the intertrochlear groove. Primary motions are:

• superior/cephalad (toward the head) with knee extension
• inferior/caudad (toward the feet) knee flexion
• Function is to increase the advantage of the quadricep for knee extension motion
• Patella alta: describes a patella that sits too high on the femur; typically due to laxity in the quadriceps tendon and increases risk for patellar dislocation
• Patella baja: describes a patella that sits too low on the femur; typically due to a tight quadriceps tendon or a tight quadriceps muscle
• The Quadriceps Angle ("Q Angle") describes the angle between the hip and the patella and the patella with the tibial tubercle
• the larger the Q angle the higher the risk for lateral knee pain and lateral patella dislocation due to increase lateral forces
• Primary factors that influence patella femoral motion:
• size of Q angle (larger = more lateral forces)
• Tight muscles and fascia
• IT band
• lateral retinaculum
• quadriceps
• Quadriceps weakness, especially vastus medialis oblique (VMO)
• Quadriceps imbalance (lateral quadricep is stronger than medial quadricep)
• Hip muscle weakness: weak abductors, weak external rotators
• Compression forces at the patellofemoral joint are high in mid-range flexion:
• In the closed kinetic chain, patellar compression is maximum at 90 degrees of flexion, and rapidly rises at 30-60 degrees of flexion.
• In the open kinetic chain, patellar compression is maximum at 30 degrees of flexion.
• Patellofemoral dysfunction syndrome (PFDS) is most often attributed to faulty, excessive lateral tracking of the patella. This can be affected by Q-angle, tight iliotibial (IT) bands/tensor fascia lata (TFL), tight gluteus maximus, weak hip abductors and tight lateral retinaculum.Additionally, the patella is attached to the tibial tubercle by the ligamentum patella. A tight gastrocnemius will laterally rotate the tibial tubercle.  Are there any foot positions that cause ER of the tibia? Keep this in mind for next week.

• The "screw home" mechanism describes the motion between the femur and tibia in the terminal extension (0-30 degrees)
• occurs because the medial femoral condyle is larger, so lateral structures (femoral condyle, meniscus) are congruent sooner with extension
• open chain: tibia externally rotates on femur in terminal extension
• closed chain: femur internally rotates on the tibia in terminal extension
• popliteus - unlocks knee with open chain motions
• hip external rotation - unlocks knee with closed chain motions
• Medial tibial condyle is longer than lateral tibial condyle. The medial femoral condyle will be moving longer than lateral condyle and will slide further posterior. This is responsible for the screw home mechanism of the knee or functional locking of the knee. The femur rotates internally to lock into extension (closed kinetic chain) The function of the popliteus muscle is to unlock the knee when standing. Adding to this concept is the fact that hip extension pulls the iliofemoral ligament tight, which can cause the last 20 degrees of knee extension, in absence of quadriceps action. A hip joint that is lacking extension will significantly impair knee extension/locking.

 Functional range of motion

The functional knee ROM of the knee is full extension for maximally efficient weight bearing, 60 degrees of flexion for swing phase of gait, 90 degrees or greater for getting into bath tubs, automobiles, and rising from sit to stand.

Postion of ease

Position of comfort is defined as 20-25 degrees of flexion, as this is the range that will accomodate the most joint effusion, post injury. Be sure to let this guide you in exercise selection for people with patellofemoral dysfunction syndrome (PFDS).

A tight IT band is commonly understood to contribute to lateral knee pain due to its connection to the lateral retinaculum. A tight TFL obviously can contribute to this process. A tight gluteus

maximus is often overlooked and will also contribute to tight IT band problems.

Summary of PT Examination

• History, Observation, Inspection, review diagnostic imaging and reports as available
• Joint motion assessment (hip, knee, ankle)
• Resisted isometric muscle assessment
• Ligament stability testing (single and combined planes)
• Palpation
• Neuro testing (DTR, sensory)
• Special tests: Joint mobility testing (tibiofemoral gliding, patellofemoral gliding)
• Functional mobility (gait, squat, balance, stairs, jumping (depends on acuity level and patient-ability)

Summary of Special Tests: Approximate Video Lengths - 10 minutes

Common Conditions

General Intervention Strategies for Non Operative Knee Conditions

Video Resource - ACL Injury Prevention - Approximately 4 minutes

Although listed as ACL prevention, these exercises are consistent with conditioning for controlled motion and dynamic stabilization at the hip and the knee during the initial loading and unloading phases of weight bearing. Educating patients who present with mild sprains in the lower quarter on exercises to prevent tears in the future is advised as an integrated part of a home exercise program

General Intervention Strategies for Post-Operative Knee Conditions

Video Resources for Knee Injuries Requiring Surgeries (Approximate time - 60 minutes)

These are excellent educational videos that provide a clear review of structure, function, typical injury patterns and grades of injury, and surgical approaches. The videos reinforce the structural roles of knee components. Although some of the anatomy information may be repetitive, full review of each linked video is recommended to support your understanding of assigned text and online lecture material.

ACL Injury with Hamstring Graft

ACL Injury with Patellar Tendon Graft

Meniscal Tears

PCL Reconstruction

Total Knee Replacement

Cruciate ligament repair highlights

Essential information to note for anterior cruciate ligament repairs (ACL):

• If patellar tendon or cadaver graft was used, always respect anterior knee pain and do not attempt to push or work through it. This is a warning sign that there is too much force placed through the tendon graft site.
• If a hamstring tendon graft was performed to repair the ligament, respect medial knee pain and do not attempt to push or work through it. This is a warning sign that there is too much force placed through the tendon graft site.
• Approved ROM for exercise training are: closed chain 0-60, open chain 90-40.

Review of ACL 12-week protocol - Video approximately 10 minutes

Posterior cruciate ligament repairs (PCL):

• Immobilization is typically about 4 weeks.
• Weight bearing will be advanced slower and exercises will be advanced slower than in an ACL reconstruction
• For both grafts and non-surgical management, the hamstrings training is very important to improving dynamic stability. Also remember that internal tibial rotation tightens/stresses both ACL and PCL ligaments

Meniscus injury and repair highlights

• Keep in mind that weight bearing must be pain free before advancing any significant stresses on the joint.
• Absolutely no undertaking of weight bearing combined with rotation on the involved leg until late in the recovery phase.
• When treating conditions associated with the medial meniscus, remember the multiple attachments that exert force on the meniscus. Excessive stress to muscles and connective tissue that attach to an partially healed meniscus will cause discomfort.
• Always take complaints of popping or clicking in the joint as very serious and notify the surgeon and the PT

Total Knee Arthoplasty highlights

There are many types of prostheses for use in TKAs (total knee arthroplasty). Surgeons drive how components are selected for patients.

Just make sure you have a general understanding of general structures that are replaced and still called "TKA"

• unicompartmental - replaces one tibiofemoral compartment (usually medial)
• bicompartmental
• total (includes patella)

All may be cemented or uncemented. Poor or reduced bone quality, advanced age, and sedentary lifestyle may increase the likelihood of the use of cement and post-operative WBAT status

Good bone health, younger age, and prior history of active lifestyle may result in increased likelihood of uncemented prosthesis and more restrictive early weight bearing orders.

Clinical Pearl: The highest priority is to attain full knee extension. Why? Try standing and walking on one slightly bent knee for any length of time (go ahead try it)! Can you appreciate how any long-term loss of extension will significantly and negatively impact function?

Gaining range into extension is an uncomfortable and often painful process. Be vigilant in patient monitoring during early rehab: are they stretching often? are they stretching effectively? are they taking the necessary steps to manage their pain? What does the use of quad setting during the knee extension stretch attain beyond passive stretching alone? Assess their understanding and positively influence their attitude toward exercise by listening and teaching. Positioning the affected limb to allow for gravity-assisted extension stretching helps with pain and long term motion gains. Add isometric quad sets and you've got a great tool for improving extension. Remember, hip flexion thighness can result in persistent knee flexion, so be sure to include hip flexion stretching and glut strengthening as needed.

Clinical Pearl: The knee must flex in order to make space for edema. Therefore, early edema management is a powerful way to prevent extension loss. (Patients who work with Christina get to hear, "You can't bend a full water balloon!")

Progressing flexion AROM is best achieved through a combination of open and closed chain activities. Start with AROM that includes static holding controlled by the patient. Reciprocal inhibition through active hamstrings recruitment is very powerful means to increase knee flexion.

Can you think of closed chain ROM or other functional activities that will increase active knee flexion and extension motion and control?

Continuous Passive Motion - an example of evidence based practice

Continuous passive motion machines (CPM) were often prescribed in the early 1990's through 2000 and beyond to help improve TKA flexion range of motion. CPM was initially supported in the evidence by animal studies. A systematic review (Harvey, Brosseau, & Herbert, 2014) of 41 randomized control trial study designs showed no significant effect on short term or long term gains in flexion or extension ROM after TKA. You may encounter CPM use today, and it is typically reserved for the acute phase or initial days of rehabilitation.

Harvey, L. A., Brosseau, L., & Herbert, R. D. (2014). Continuous passive motion following total knee arthroplasty in people with arthritis. The Cochrane Library.

Patellofemoral Dysfunction Syndrome

This condition is covers pain presentations at or around the patella. Major sources of patellofemoral dysfunction are attributed to altered patella tracking in the tibiofemoral joint and arthritic changes under the patellar surface. Bursa above and below the patella can also become inflammed, resulting in knee pain and altered mechanics.

Patellofemoral dysfunction can also evolve after a total knee replacement or prior knee injury, so monitoring patellofemoral mobility and control is often a component of knee rehabilitation

Video explaining of Patellofemoral Dysfunction - Approximately 6 minutes

Presentation

• Pain in or under the patella "knee cap"
• Pain with running and jumping
• Pain with prolonged sitting or unable to sit due to patella pain (Positive + "movie sign")
• Pain with stair climbing
• Patella may be positioned high (patella alta), low (patella baja), or laterally - most typical is lateral and high due to imbalance between medial forces on the knee and tight lateral structures pulling on the patella

Interventions

• medial quad strengthening
• IT band stretching
• taping or bracing
• progressive strengthening for return to squatting and stairs

Video of Sample Interventions - Approximately 10 minutes

Data Collection

Data collection guides decision making for activity progression and communication with the supervising physical therapist. The PTA should be documented relevant data in order to guide the rehabilitation plan and promote optimal function. Examples of data to collect to inform clinical decision making and care planning include:

Maximum protection phase

• limb appearance: color size, scar healing, edema, atrophy
• pain: levels, type, activity related, use of medication, ice, compression, etc., for pain management
• posture: weight bearing habit in sagittal, frontal, and transverse planes, compensation in the spine, pelvis, and lower quarter, postural abnormalities
• limb circumference: typically measured at joint line, 5-10cm above and below the joint line
• use of braces and assistive devices: is the patient using them as indicated consistently and appropriately? are they in good condition
• exercise and protective activity adherence: is the patient using PRICE, limiting WB activity, performing self-range of motion as directed? any barriers to exercise adherence?
• range of motion: passive and active assisted only for maximum protection
• aerobic exercises: activities that maintain overall cardivascular fitness

Controlled motion phase

• skin, particularly mobility of tissue and/or incisions
• pain levels, location, activity restrictions
• continue with posture monitoring, swelling monitoring, PROM, and use of braces or least restrictive and most appropriate assistive device
• strength tests
• endurance for partial weight bearing and non weight bearing strengthening
• balance and postural control in static standing on one leg, with or without supports
• active ROM and motion control in open and closed chains
• strengthening progression quality and adherence
• gait training quality, distance, device, pattern, compensation, step height

Return to function phase

• endurance (sets, reps, running, jumping)
• stability and mobility during agility drills
• functional movements and activities: squatting, kneeling, pivoting, jumping running

Signs indicating a need to communicate with the supervising physical therapist include:

• recurrent or abnormal swelling or redness
• complaints or reports of popping, clicking, or "giving away"
• persistent loss of extension or flexion inconsistent with healing phase
• significant indicators of poor patient adherence to joint protections (e.g. premature return to sport, discontinuing bracing, etc)
• pain levels that are persistently high at rest or during activity

End of Lesson