Postoperative Instructions Following Partial Knee Replacement

Postoperative care following Unicompartmental Knee Arthroplasty (UKA) shares critical long-term precautions with Total Knee Replacement (TKR). However, the recovery timeline is substantially accelerated: surgical pain is milder, hospital discharge occurs sooner, and functional mobility returns weeks earlier. A unique objective of UKA rehabilitation is strengthening both the operated compartment and the preserved healthy compartment to safeguard native joint architecture against premature wear.

Immediate Postoperative Care & Sleeping Ergonomics

Immediate Mobilization: Full weight-bearing with a walker or crutches begins on postoperative day one under physical therapy guidance.
Sleeping Position: Sleep supine (on your back) with the operated leg elevated. Place pillows under the calf or heel—never place a pillow directly beneath the knee joint, as maintaining a persistent flexion posture encourages flexion contractures and joint stiffness.
Side Sleeping: Avoid sleeping on the operative side during the first postoperative week.

Crucial Restrictions: What to Avoid

Permanent Prohibitions: Floor sitting, deep squatting, running, and high-impact jumping must be avoided permanently to prevent polyethylene wear and excessive component stress.
Temporary Precautions (3–4 Months): Avoid low chairs or deep sofas that force knee flexion beyond 90° during sit-to-stand transfers.
Rehabilitation Adherence: Do not discontinue physical therapy prematurely once surgical soreness subsides; ongoing muscle conditioning is required to offload the untreated compartment.

The Role of Physical Therapy

Postoperative rehabilitation after UKA serves a dual purpose: restoring quadriceps activation across the surgical site and balancing mechanical load distribution to protect the preserved compartment.

Protocol Length: 12 to 20 structured sessions over 4 to 8 weeks.
Core Regimen: Ankle pumps (DVT prophylaxis), isometric quadriceps sets, straight leg raises (SLR), and progressive active-assisted range-of-motion (ROM) exercises.

Recovery Timeline & Resuming Activities

Independent Walking: Transition from assistive devices to unassisted ambulation within 1 to 2 weeks.
Driving: Permitted within 2 to 3 weeks once narcotics are discontinued and rapid braking reaction time is restored.
Functional Recovery: Daily routine activities resume within 4 to 8 weeks; full tissue remodeling and maximal strength gains take 6 to 12 months.

Red-Flag Symptoms Requiring Prompt Clinical Contact

Fever (> 38.3°C), chills, or purulent wound drainage: Potential periprosthetic infection.
Calf swelling, severe tenderness, or sudden shortness of breath: Signs of deep vein thrombosis (DVT) or pulmonary embolism.
Joint stiffness: Active knee flexion remaining below 90° at 8 weeks post-op.
Sensation of knee instability or mechanical giving way.

Frequently Asked Questions: Postoperative Instructions Following Partial Knee Replacement

When can I begin walking and bearing weight after a Partial Knee Replacement?

Full weight-bearing as tolerated begins immediately on the day of surgery or within the first 24 hours. Under the supervision of a physical therapist, you will practice standing, walking, and climbing stairs using a walker or elbow crutches. Most patients transition to unassisted walking within 1 to 2 weeks as quadriceps control returns.

How should I position my leg when resting or sleeping?

Always maintain your operative leg in a straight, fully extended position. When resting, elevate your foot and calf by placing pillows under your ankle or lower calf so that the leg rests above the level of your heart. Never place a pillow directly beneath your knee, as keeping the joint flexed promotes scar tissue contracture and loss of full terminal extension.

What are the wound care and showering guidelines after surgery?

Follow these essential wound care steps:

Keep the original surgical dressing sterile, clean, and dry.
Showering is generally permitted after 48 to 72 hours if you apply an impermeable waterproof cover over the knee dressing.
Pat the area dry gently after bathing; do not rub the incision.
Avoid full submersion (baths, hot tubs, pools) until all skin staples or sutures are removed and the incision is fully sealed.

How do I manage post-operative pain and swelling at home?

Effective pain management is achieved through a multimodal approach:

Take prescribed medications on schedule rather than waiting for breakthrough pain.
Apply cryotherapy (ice packs wrapped in a thin towel) for 15 to 20 minutes every 2 hours.
Elevate the operative leg above heart level during periods of rest.
Balance active exercise periods with adequate rest intervals.

What medications are essential after discharge from the hospital?

Your discharge prescription plan typically includes:

Thromboprophylaxis (Blood Thinners): Oral anticoagulants or aspirin taken daily for 2 to 4 weeks to prevent deep vein thrombosis (DVT).
Analgesics & NSAIDs: Scheduled medications to control pain and localized inflammation.
Prophylactic Antibiotics: If prescribed for specific indications.
Gastrointestinal / Stool Softeners: To counter constipation associated with opioid analgesics.

Which home exercises should I perform during the early recovery phase?

Consistent performance of foundational home exercises is critical:

Ankle Pumps: 20–30 repetitions every hour to stimulate calf muscle pump action and prevent blood clots.
Quadriceps Sets: Tightening the thigh muscle and pressing the back of the knee flat against the bed for 5 seconds.
Straight Leg Raises: Elevating the straightened leg 6–12 inches off the bed to restore active quad control.
Heel Slides: Gently sliding the heel toward your buttocks to progressively improve flexion.

When is it safe to resume driving after Partial Knee Replacement?

Most patients can safely drive within 2 to 4 weeks post-surgery. Before operating a vehicle, you must:

Be completely off all narcotic pain medications.
Demonstrate rapid braking reaction time and full motor control of the operative leg.
Gain clearance from your orthopedic surgeon at your initial follow-up visit.

How should I prepare my home environment to prevent falls during recovery?

Set up a safe home recovery space by removing loose area rugs, clearing cords from walkways, ensuring bright night-lighting in hallways, placing frequently used items within arm’s reach, and using a firm chair with sturdy armrests to facilitate standing up.

When can I return to work and light recreational activities?

Patients with sedentary desk jobs typically return to work within 2 to 3 weeks (with provision for intermittent leg elevation). Physically demanding or labor-intensive occupations require 6 to 8 weeks. Low-impact cardiovascular activities (stationary cycling, swimming once the wound is closed, and level walking) can commence between 4 and 6 weeks.

What red-flag symptoms require immediate contact with my orthopedic surgeon?

Seek immediate clinical evaluation if you develop any of the following warning signs:

Fever over 38.3°C (101°F) or persistent chills.
Spreading redness, warmth, or purulent drainage from the surgical incision.
Severe, worsening pain in the calf or swelling in the lower leg that does not resolve with elevation.
Sudden onset of shortness of breath, rapid heart rate, or chest pain (emergency medical attention required).