Knee Arthroplasty Rehabilitation

Knee Arthroplasty Rehabilitation

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

Knee Arthroplasty Classifications

• Classifications based on the portion of the knee replaced:

• Uni-compartmental: Replacing opposing articular surfaces of the femur and tibia, either medial or lateral compartment; often has poor results.

• Bi-compartmental: Replacing the opposing articular surfaces of the femur and tibia, including both medial and lateral compartments.

• Tri-compartmental: Similar to bi-compartmental, but also resurfacing the patellofemoral articulation.

• Classifications based on mechanical constraint:

• Un-constrained

• Semi-constrained

• Fully constrained

• Classifications based on the type of fixation:

• Cemented

• Cementless

Preoperative Rehabilitation

• A preoperative visit records baseline information, including pain, swelling, functional abilities, range of motion (ROM), and muscle strength.
• Patients practice exercises, like isometric quadriceps, that will be used post-surgery.
• Training on walking aids like walkers or crutches is crucial.
• If a continuous passive motion (CPM) machine is available, patients should try it before surgery.

Early Postoperative Stage (Day One)

• Deep breathing and coughing are crucial to avoid pressure sores.
• Ankle pumps should be performed 10 times every 2 hours to improve circulation and reduce the risk of deep vein thrombosis (DVT).
• Gluteal sets, upper extremity exercises, patella movement are a part of the daily routine.
• Quadriceps sets are repeated hourly throughout the day; this helps reduce joint effusion, pain-induced muscle inhibition, and improve inner range strength.
• Patients should prepare themselves for the sliding leg raising (SLR) exercises.

Two Main Forms of Management (No CPM)

• The knee is maintained in an extended position for 4 days using a pressure bandage and splint.
• A large compression bandage is applied.
• A back splint keeps the leg straight to prevent movement and reduce pain.
• Active exercises are not allowed until the splint is removed.
• Assisted weight bearing is possible from day two.

Postoperative Mobilization (After the splint removal)

• Patients will do passive mobilization of the patella and the scar. This helps relieve knee pain and increases flexion.
• Start active assisted knee flexion exercises at least twice a day for 20 minutes.
• Patients usually go home 5-6 days post-operation (without complications).
• Goal by postoperative day 7 is for 50-70 degrees of active knee flexion.

Return of Knee Flexion, 50-70 Degrees

• Continue the process of increasing knee flexion by at least 10 degrees every day at home.
• If 50-70 degrees of flexion isn't met on day 7, start continuous passive motion (CPM) machine for at least 6 hours per day to maximize knee flexion.
• The knee should reach 80-90 degrees of flexion by day 14.
• If a CPM machine is unavailable, manipulation under anesthesia could be considered.
• Water therapy is helpful if available.

Continuous Passive Motion (CPM) Machine

• CPM is used immediately post-operatively (up to 4 days).
• CPM is applied to control knee flexion to 40 degrees in the first 24 hours and gradually increase up to 80-90 degrees until day 7.

Disadvantages of CPM

• Increased time in bed
• Loss of independence due to extended use of CPM
• Discomfort related to CPM use
• Incidence of common peroneal nerve palsy
• Patients using CPM often develop quadriceps lag, so a splint may be needed at night to prevent knee flexion.

Extensor Lag or Fixed Flexion Deformity

• This is common amongst patients on CPM due to an imbalance between gain in flexion and extension.
• Several exercises are done to overcome this issue like:
• Progressing passive knee flexion until the extensor lag is reduced.
• Utilizing gentle manual mobilization techniques.
• Performing inner range quadriceps strengthening and hamstring/posterior knee stretching.

Functional Rehabilitation

• Begins in week 3.
• Includes closed-chain exercises (sitting to standing from varying heights, step-ups, and stationary cycling).

Proprioception Training

• Loss of proprioception is common post-replacement, exacerbated by ACL and joint capsule removal.

Walking

• Patients should use crutches or a walker for 6 weeks (cemented prostheses) or 12 weeks (cementless prostheses), and then a cane for 4-6 months.
• Walk rhythmically and smoothly, without hurrying.
• Adjust step length and speed, gradually increasing weight bearing on the affected leg.
• Use a crutch or cane on the unaffected side.
• Avoid limping or leaning away from the operated knee.

Stairs

• Initially, use handrails and ascend/descend stairs one step at a time ("up with the good, down with the bad").
• As strength improves, ascend/descend stairs foot over foot.

Driving, Jumping, and Running

• Knee joint proprioception and inner range quadriceps strength/ROM are required for driving.
• Avoid twisting, turning, jumping and running for at least 3 months (some surgeons recommend 6 months).
• Best knee implants offer near 80-85% of normal function.
• Total knee replacement is mechanically simpler than total hip replacement, likely leading to 90-95% of normal function.

Activity Guidelines (Cemented vs. Cementless)

• Cemented and cementless prostheses have slightly varying guidelines for range of motion, isometric exercises, active exercises, and resisted exercises. Specific timing for each is described in the table.
• Postoperative ambulation guidance (partial vs. full weight bearing) differs based on cemented or cementless prosthesis.

Problem Solving Exercises (Example)

• A patient with a 3-day-old knee implant showing increased swelling and warmth after exercise could indicate infection or DVT.
• Addressing these conditions involves body temperature checks, swelling checks, pain evaluation for DVT assessment, and applying ice.

Important Notes

• This information is for educational purposes only. Consult with a medical professional for specific instructions regarding your condition.