Total Knee Arthroplasty (TKA) Rehabilitation Protocol

This protocol outlines a comprehensive physical therapy rehabilitation program following a Total Knee Arthroplasty (TKA). It is a guideline and should be modified based on individual patient needs, surgical technique, and physician preferences. Close communication with the surgeon is crucial throughout the rehabilitation process.

I. Pathophysiology

Total Knee Arthroplasty (TKA) is a surgical procedure where damaged or diseased articular surfaces of the knee joint are replaced with artificial components. The primary indications for TKA include:

• Osteoarthritis: Progressive degeneration of joint cartilage leading to pain, stiffness, and decreased function.
• Rheumatoid Arthritis: An autoimmune disease causing inflammation and damage to the joint lining.
• Post-traumatic Arthritis: Arthritis resulting from a previous knee injury (e.g., fracture, ligament tear).
• Avascular Necrosis: Death of bone tissue due to insufficient blood supply.

The surgical procedure involves resecting the damaged bone and cartilage of the distal femur, proximal tibia, and often the patella. Metal and plastic components are then implanted to recreate the joint surface, allowing for smoother and pain-free movement. The underlying cause of the arthritis, the severity of the damage, and the patient's pre-operative condition all influence the outcome and rehabilitation process.

II. Phase I: Protection (Weeks 0-4 Post-Op)

Goals: Control pain and swelling, protect the healing tissues, achieve independent ambulation with assistive device, achieve 0-90 degrees of knee flexion, initiate quadriceps control.

• Pain and Edema Management:
  • Cryotherapy: Apply ice packs for 20-30 minutes several times per day.
  • Elevation: Elevate the leg above heart level to promote venous drainage.
  • Compression: Use compression bandages to minimize swelling.
  • Medication Management: Follow physician’s prescribed pain medication regimen.
• Early Mobilization:
  • Ankle Pumps: Perform frequently throughout the day to prevent blood clots.
  • Quadriceps Sets: Isometric contractions to activate the quadriceps muscle.
  • Hamstring Sets: Isometric contractions to activate the hamstring muscles.
  • Gluteal Sets: Isometric contractions to activate the gluteal muscles.
  • Heel Slides: Gentle knee flexion and extension exercises.
• Range of Motion (ROM):
  • Continuous Passive Motion (CPM) Machine: Use as prescribed by the surgeon. Start with a limited range and gradually increase the arc of motion.
  • Active Assisted Range of Motion (AAROM): Use a towel or sheet to assist with knee flexion and extension.
  • Passive Range of Motion (PROM): Therapist provides range of motion exercises, as needed, if active range of motion is limited.
• Gait Training:
  • Begin with a walker or crutches for ambulation.
  • Progress to partial weight-bearing as tolerated, following surgeon's instructions.
  • Focus on proper gait mechanics, including heel strike, midstance, and toe-off.
• Strengthening:
  • Open chain exercises such as Short Arc Quads (SAQ) may be initiated if deemed safe.
  • Hip abduction and adduction exercises.
  • Core stabilization exercises.
• Precautions:
  • Avoid excessive stress on the knee joint.
  • Follow weight-bearing restrictions prescribed by the surgeon.
  • Avoid activities that cause pain or swelling.
  • Be mindful of wound healing and signs of infection.

III. Phase II: Loading (Weeks 4-12 Post-Op)

Goals: Improve ROM to 0-120 degrees of knee flexion, improve strength and endurance, normalize gait pattern, begin functional activities.

• Range of Motion (ROM):
  • Continue AAROM and PROM exercises.
  • Patellar mobilization to prevent scar tissue formation and improve patellar tracking.
  • Static stretching exercises to improve knee extension and flexion.
• Strengthening:
  • Weight shifting exercises to improve balance and proprioception.
  • Mini-squats, focusing on proper form and alignment.
  • Leg press (light resistance).
  • Hamstring curls (light resistance).
  • Calf raises.
  • Closed kinetic chain exercises (CKC), such as step-ups and lunges (progress with caution).
• Balance and Proprioception:
  • Single-leg stance (progress from eyes open to eyes closed).
  • Balance board or wobble board exercises.
  • Weight shifting with perturbations.
• Cardiovascular Endurance:
  • Stationary cycling (low resistance).
  • Elliptical training.
  • Swimming (when wound is fully healed).
• Gait Training:
  • Progress to full weight-bearing as tolerated.
  • Address any gait deviations.
  • Begin inclines and declines.
• Functional Activities:
  • Stair climbing (ascending and descending).
  • Step over objects.
  • Walking on uneven surfaces.
• Precautions:
  • Avoid high-impact activities.
  • Monitor for signs of inflammation or pain.
  • Proper warm-up and cool-down routines.
  • Progress exercise intensity gradually.

IV. Phase III: Return to Function (Weeks 12+ Post-Op)

Goals: Maximize strength, endurance, and functional abilities, return to recreational activities.

• Advanced Strengthening:
  • Progress resistance on all exercises as tolerated.
  • Plyometric exercises (e.g., jumping jacks, box jumps – cautiously and with appropriate technique).
  • Isokinetic exercises (if available).
• Sport-Specific Training (if applicable):
  • Agility drills (e.g., cone drills, shuttle runs).
  • Sport-specific movements and exercises.
  • Gradual return to sport participation, following surgeon's guidelines.
• Maintenance Program:
  • Home exercise program to maintain strength, ROM, and endurance.
  • Regular follow-up appointments with physical therapist as needed.
• Precautions:
  • Avoid activities that cause pain or swelling.
  • Proper warm-up and cool-down routines.
  • Use appropriate protective equipment when engaging in sports or recreational activities.

V. Common Special Tests

While special tests are less critical post-TKA than in other knee conditions, they can help rule out other pathologies or identify potential complications. These tests should be performed cautiously and modified as needed, considering the presence of the prosthesis.

• McMurray's Test: Evaluates for meniscal tears. Perform cautiously.
• Apley's Grind Test: Evaluates for meniscal tears. Perform cautiously.
• Lachman Test & Anterior Drawer Test: Assesses anterior cruciate ligament (ACL) integrity. Less relevant but can help rule out other issues.
• Varus/Valgus Stress Test: Assesses medial and lateral collateral ligament (MCL/LCL) integrity. Important to check for instability.
• Patellar Apprehension Test: Assesses patellar instability.
• Ober's Test & Thomas Test: Assess hip flexor tightness which can impact knee mechanics.

Disclaimer: This protocol is a guideline and should be adapted to meet the individual needs of each patient. Always consult with the surgeon and physical therapist before making any changes to the rehabilitation program.