Knees

Total Knee Arthroplasty and Clinical Context

• Total Knee Arthroplasty ($TKA$), also known as a total knee replacement, involves the surgical replacement of the entire knee joint with an artificial joint.
• This procedure is typically recommended for patients recovering from surgery rather than those with minor trauma, such as a simple bruise from a fall.
• The knee is considered one of the simplest topics within orthopedics for recovery and study, serving as an entry point for understanding more complex orthopedic conditions.

The Three P's of Orthopedic Recovery: General Principles

There are three core concepts applied to every orthopedic condition, referred to as the Three P's: Pain, Positioning, and Performance.

• Pain: Post-surgical management requires a specific approach based on the timing of recovery.
  • Cryotherapy and Acute Recovery: During the first few days following surgery ($post-op$) or severe trauma, inflammation and swelling are significant. Only cold (cryotherapy) is used during this time. Heat must be avoided because it increases blood flow and circulation, which would exacerbate swelling.
  • Late-Stage Recovery: Heat may be used later in the recovery process depending on what the individual finds beneficial.
  • Balancing Pain and Activity: There is a critical balance between respecting a client's pain experience and encouraging functional activity. While pain should not be ignored or met with a "toughen up" attitude, the goal remains to achieve as much independence as possible.
• Positioning: Specific precautions and positions are required to promote proper healing of the joint and surrounding tissues.
• Performance: The clinical focus is on functional Activities of Daily Living ($ADL$).
  • While the biomechanical frame of reference has a place in orthopedics, Occupational Therapy ($OT$) focuses primarily on independence rather than just therapeutic exercise ($therex$). Recovery from surgery is not a justification for focusing solely on exercises over functional tasks.

Positioning Strategies and the "Straightforward" Framework

The metaphor "Knees are Straightforward" reflects three specific clinical aspects of this joint:

• Simplicity: The recovery process for $TKA$ is relatively simple and direct compared to other joints like the hip.
• Extension at Rest (Straight): It is clinically vital to maintain the knee in full extension while at rest.
  • It is significantly easier to gain flexion (bending) in a stiff knee than it is to gain extension (straightening).
  • If a knee becomes stiff while in a flexed position, it can lead to a flexion contracture. Correcting this is extremely painful, difficult, and time-consuming.
  • The practical solution is to position the knee in full extension as much as possible so that if stiffness occurs, the knee is in a position from which functional movement can more easily be restored.
• No Twisting (Forward): Patients must keep their knee oriented forward and avoid any twisting or rotational movements through the joint to ensure proper healing.

Clinical Application of Pillow Support

• Prohibited Placement: Pillows should never be placed directly underneath the knee. While this may be the most comfortable position for the patient, it promotes flexion, which increases the risk of stiffness and contracture.
• Correct Placement: Pillows or support should be placed distal to the knee (under the lower leg/calf). This positioning allows gravity to pull the knee joint down into extension.

Functional Performance and Early Post-Surgical Mobility

• Early Ambulation: Patients are typically encouraged to move and get out of bed as early as $post-op$ Day $1$.
• Weight-Bearing Status: The most common weight-bearing order after knee surgery is Weight Bearing As Tolerated ($WBAT$), meaning the patient can put as much weight on the limb as they can comfortably handle, though the specific physician's orders must always be verified.
• Barriers to Mobility: The primary obstacle for $TKA$ patients is usually not walking (ambulating) but the transition between sitting and standing ($sit-to-stand$ or $stand-to-sit$). This transition places the highest demand on the knee joint as it moves from a bent to a straight position.

Strategies for Transfers, Toileting, and Bathing

• Upper Extremity Support: To manage the difficulty of sit-to-stand transitions, patients are taught to recruit their arms. The use of armrests, grab bars, and handholds is essential to assist the lower extremities during movement.
• Toileting Equipment:
  • Toilet Safety Frame: Provides armrests around the toilet to assist with sitting and standing.
  • Raised Toilet Seat: Increases the height of the sitting surface, reducing the distance the knee must travel during the transition.
  • Commode Chair: This can be used over the existing toilet to provide both height and armrests, or used at the bedside if the patient has significant difficulty with ambulation or if their bathroom cannot accommodate a wheelchair.
• Bathing Techniques:
  • Safety: Non-slip strips and shower chairs are vital to prevent falls.
  • The Sidestep Technique: Cited as a gold standard for tub transfers without a transfer bench. The patient faces the wall, holds onto a grab bar, and steps sideways over the lip of the tub rather than stepping into it while facing forward.

Activities of Daily Living and Adaptive Equipment

Limited range of motion and the use of knee immobilizers (which hold the knee in extension) make it difficult for patients to reach their lower extremities.

• Dressing: Standard adaptive equipment is used to compensate for the inability to bend the knee comfortably:
  • Reachers and dressing sticks.
  • Sock aids.
  • Long-handled shoe horns.
• Personal Hygiene: A long-handled sponge is used to assist with bathing the lower legs and feet.
• Immobilizer Management: Part of the $OT$ intervention involves training the patient on how to don (put on) and doff (take off) their knee immobilizer as prescribed by their physician.

Questions & Discussion

Case Scenario: A $70$-year-old client is $2$ weeks post-op from a right total knee replacement. The client has met all long-term goals and is preparing for discharge. The $OT$ must educate the client and caregiver on safe car transfers.

• Question: Which option is most appropriate when teaching car transfers?

  • A: Ensure the caregiver is available to provide maximum assist.
  • B: Ensure the passenger seat is pushed back as far as it can go and reclined prior to getting into the car.
  • C: Teach the client to use a walker and to take very small steps when pivoting toward the car.

• Discussion and Rationale:

  • Option A is incorrect because it is vague and non-specific. It does not demonstrate a clinical understanding of $TKA$ precautions or safety.
  • Option B is often associated with hip replacement precautions (posterior hip precautions) where reclining prevents excessive hip flexion. While pushing the seat back might be comfortable, the reclining aspect is more characteristic of a hip answer.
  • Option C is the correct answer. It addresses the primary precaution for knees: avoiding twisting. By taking small steps with a walker rather than pivoting their feet while the body turns, the patient avoids the rotational force that could damage the healing knee joint.

• Clinical Reasoning: Exam questions regarding $TKA$ specifically look for knowledge regarding joint precautions, such as the avoidance of twisting and the maintenance of extension.