Rehabilitation following knee surgery is a structured and highly individualized process that determines the success of returning to normal activity. Exercise is a fundamental component of this recovery, helping to restore joint mobility, rebuild muscle strength, and improve functional capacity. While this overview provides insight into the typical progression of exercises, it is imperative that every movement be performed under the direct guidance of a surgeon or physical therapist. Their instruction ensures exercises are appropriate for the specific surgical procedure and your unique healing timeline.
Initial Focus: Restoring Range of Motion
The immediate phase following knee surgery, typically the first two weeks, centers on controlling swelling, protecting the surgical site, and initiating gentle motion to prevent joint stiffness. The primary objective during this period is to regain full knee extension, which is crucial for a normal walking gait, and achieve a functional degree of flexion. Circulation is supported through simple movements like ankle pumps, where the foot is repeatedly flexed and pointed, which helps reduce the risk of blood clots.
Muscle activation without joint movement is addressed through quadriceps setting, or “quad sets,” where the thigh muscle is tightened, pressing the back of the knee down against the bed or floor. This static contraction reactivates the quadriceps, which are often inhibited immediately after surgery, and is a foundational step in restoring control. Heel slides are introduced to gently initiate knee flexion, involving sliding the heel toward the buttocks while lying on the back. This passive range of motion exercise helps to reduce stiffness and works toward an initial flexion goal, often aiming for approximately 90 degrees in the first few weeks.
Achieving full extension is often given priority, sometimes using a towel roll placed under the heel while the knee remains straight, allowing gravity to assist. This gentle stretch helps counter the common tendency for the knee to settle into a slightly bent position, which can hinder long-term recovery. These early movements are performed frequently throughout the day, often in sets of 10 to 15 repetitions, to maintain consistency without causing undue stress or inflammation.
Building Strength: Early Muscular Engagement
Once the initial swelling is managed and a foundational range of motion is established, usually around two to six weeks post-surgery, the rehabilitation shifts toward strengthening the musculature surrounding the knee. The quadriceps, which naturally weaken significantly after surgery, are targeted first through exercises that avoid excessive joint strain. The straight leg raise is a common movement in this phase, performed by tightening the thigh muscle and lifting the straight leg a few inches off the surface, which activates the quadriceps without bending the knee.
This progression allows for the rebuilding of muscle power in the thigh before introducing significant weight bearing. Short arc quads, performed with the knee slightly bent over a bolster or rolled towel, further isolate the quadriceps muscle. The patient actively straightens the leg against the bolster, engaging the muscle through a limited, protected range of motion.
As strength improves, the patient gradually transitions from non-weight-bearing positions to partial weight-bearing activities. Standing hamstring curls are introduced to strengthen the muscles at the back of the thigh, which are important for balancing forces around the knee joint. This involves standing and bending the knee to bring the heel toward the buttocks, often while holding onto a stable surface for balance. Seated knee extensions, where the knee is slowly straightened while sitting, help to build endurance and strength in a controlled manner.
Functional Movement and Balance Training
The next stage of rehabilitation, typically beginning after six weeks, concentrates on exercises that prepare the knee for the demands of daily life and physical activity. The goal shifts from isolated muscle strengthening to compound movements that integrate the entire leg and improve stability. Stationary cycling is often introduced because it provides non-impact, repetitive motion that improves joint mobility and cardiovascular endurance. The seat height is initially adjusted to ensure the knee is nearly straight at the bottom of the pedal stroke, protecting the joint while increasing range of motion.
Partial squats are a fundamental functional exercise, as they mimic the motion required for sitting down and standing up. These are performed with the back against a wall or using a stable support, gradually lowering the body only a short distance to protect the joint from excessive load. Step-ups and step-downs, performed on a low platform or stair, are crucial for training the knee to handle the impact and stability required for navigating stairs and curbs. The focus is on controlled movement, ensuring the knee tracks correctly over the foot.
Balance and proprioception, the body’s sense of its position in space, are refined through single-leg stance drills. Standing on the operated leg without support helps retrain the stabilizing muscles around the knee and hip to react to subtle shifts in weight. Advanced balance work may include performing a single-leg stance on an unstable surface or adding a gentle reach with the opposite foot.
Safety Guidelines and Progression Pacing
Progression through rehabilitation must be guided by clinical criteria, such as pain level and range of motion milestones, rather than a rigid timeline. A general rule of thumb is that exercise should cause a working ache or mild discomfort, but never sharp or stabbing pain within the joint. Any sudden increase in pain, excessive swelling, or fever is a warning sign that requires immediate consultation with a physical therapist or surgeon.
It is imperative to avoid high-impact activities, such as running or jumping, and twisting motions across the knee joint, especially in the early months, as these can jeopardize the surgical repair. The physical therapist will dictate when resistance, such as ankle weights, can be safely added to exercises, which is typically after the initial six weeks. Consistency is more beneficial than intensity; performing exercises multiple times a day as prescribed is more effective than infrequent, strenuous sessions.
Managing Recovery
Listen to the body’s response, use ice and elevation to manage post-exercise swelling, and understand that a full recovery is a gradual process that can take several months.