Knee Arthroplasty Basics Quiz

Knee Arthroplasty Rehabilitation

• Knee arthroplasty is the surgical construction of a new, artificial, painless, movable, and stable knee joint.
• Indications for surgery are severe painful joints, with or without deformity. Common causes include rheumatoid arthritis, osteoarthritis, and traumatic arthritis.
• Contraindications include bone infection, severe osteoporosis, recent joint sepsis, and malignant tumors.

Classifications of Knee Arthroplasty

• Uni-compartmental: Replacing the opposing articular surfaces of the femur and tibia on either the medial or lateral side; often not as successful.
• Bi-compartmental: Replacing the opposing articular surfaces of the femur and tibia on both the medial and lateral sides.
• Tri-compartmental: Same as bi-compartmental with resurfacing of the patellofemoral articulation.

Preoperative Rehabilitation

• The first purpose of the preoperative visit is to record baseline information.
• This includes: pain and swelling, functional abilities and range of motion (ROM), and muscle strength.
• The second purpose is to prepare the patient for the postoperative program.
• This includes practice with exercises used after surgery, such as isometric quadriceps exercises.
• Training with walking aids (walker or crutches) and CPM machines should also be done before surgery.

Early Postoperative Stage (Day One)

• Deep breathing and coughing exercises are crucial to prevent complications and pressure sores.
• Ankle pumps (10 times every 2 hours) promote circulation and minimize deep vein thrombosis (DVT).
• Gluteal sets, upper extremity exercises, and patella movement exercises will be part of daily routine.
• Quadriceps sets (10 times per hour) reduce joint effusion and pain and help achieve inner-range strength.
• SLR exercises should begin after the first two days.

Two Main Forms of Management (No CPM)

• The knee is maintained in an extended position for 4 days with a large compression bandage and splint.
• This prevents movement and reduces pain.
• No active exercise can be done until the bandage/splint is removed.
• Assisted weight bearing begins from day 2 without active knee exercises during this stage.

Post-Removal (After 4 Days)

• Passive mobilization of the patella and the scar is crucial to reduce pain and increase flexion.
• Active assisted knee flexion is vital, starting twice daily for 20 minutes or more.
• Patients are typically discharged 5-6 days post-operation, assuming no complications arise.
• By day 7 post-op, ideally 50-70 degrees of active knee flexion should be achieved.

CPM (Continuous Passive Motion)

• Used immediately after surgery for up to 4 days, with a 6-hour daily routine.
• Controls flexion range at 40 degrees during first 24 hours and gradually increases by 10 degrees per day to 80-90 degrees by day 7.
• Active knee flexion returns more quickly with CPM than without it.
• Weight-bearing with the splint is possible two days post-op, without the splint 1-2 days later.
• CPM can hasten quadriceps strength.

CPM and Disadvantages

• Increased bed time, loss of independence, and discomfort are some common disadvantages of CPM in the early stage.
• Increased incidence of common peroneal nerve palsy and quadriceps lag are also observed.
• Patients on CPM should wear a splint at night.

Fixed Flexion Deformity

• This can be a particular problem for the CPM group due to an imbalance between flexion and extension gains.
• Methods to solve this problem include passive flexion progression halt until the extensor lag reduces and manual mobilization techniques to increase extension.

Functional Rehabilitation (Start at Week 3)

• Closed chain exercises (e.g., sitting up, stepping up/down, step-ups, small arc cycling) are introduced.

Proprioception Training

• Loss of proprioception (sensation about the position of the limb in space) is a normal part of knee joint replacement, which is often accentuated by removing parts of the joint capsule, including the ACL.

Walking

• Crutches/walkers (6-12 weeks) are used to support patients depending on the prosthetic type (cemented vs. cement-free) for the first few weeks to months.
• Patients should walk rhythmically, smoothly, and gradually increase the step length and leg weight bearing. Avoid limping and leaning away from the operated knee.

Stairs

• Handrails are typically required initially to aid in balance support with ascending (up with the good knee). Ascending and descending stairs (up with the good/down with bad) is excellent strengthening and endurance training.

Driving and Activities

• Driving, twisting, turning, jumping, and running should be avoided for at least 3 months.
• Some doctors extend this restriction to 6 months.

Knee Replacement Guidelines and Precautions

• Activity, range of motion, isometric and active exercises, resisted exercises, and ambulation have specific guidelines which are determined by the prosthetic type, or cemented vs. cement-less.

Problem-Solving Exercises

• Patients with new knee replacement pain and increased swelling have potentially caused issues with infection, DVT, or incorrect movement into flexion. ICE, positioning, and other considerations should be attempted.