A sprained knee occurs when one or more of the ligaments supporting the joint are stretched or torn. Ligaments are fibrous tissues that connect bones and provide stability to the knee. Proper rehabilitation is necessary for the ligament to heal effectively and for the joint to regain full function. The recovery involves a structured progression from immediate protection and pain control to restoring full strength and preparing the knee for physical activity.
Immediate Care and Initial Stabilization
The first 48 to 72 hours following a knee sprain focus on minimizing damage and managing inflammation using the P.R.I.C.E. protocol: Protection, Rest, Ice, Compression, and Elevation. Protection involves using crutches, a brace, or a supportive wrap to prevent movements that could worsen the injury.
Rest means avoiding activities that stress the joint, allowing initial healing. Ice should be applied for 15 to 20 minutes several times a day to reduce pain and limit swelling; wrap the ice pack in a thin towel to protect the skin.
Compression, typically with an elastic bandage, limits fluid accumulation, which reduces pain and stiffness. Elevation of the injured leg above the heart uses gravity to assist in draining excess fluid. Pain management can be aided by over-the-counter medications such as acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen.
Restoring Range of Motion and Flexibility
Once initial swelling and pain subside, the focus shifts to preventing joint stiffness and restoring the knee’s full range of motion. This phase transitions from passive rest toward gentle, active movement, which helps the joint receive nutrients and clear waste products. These early exercises must be slow and controlled, stopping immediately if sharp pain occurs.
The Heel Slide is performed by lying on the back and gently sliding the heel toward the buttocks to bend the knee, restoring the ability to flex. To regain full knee extension, the Passive Knee Extension hold can be used, where the heel is propped up and a small weight is placed on the thigh.
The Quadriceps Set involves the isometric contraction of the thigh muscle while the leg is straight. This action helps re-establish the nerve-muscle connection, which is often inhibited after injury, without moving the joint. Consistent, gentle movement in this stage improves flexibility and mobility, preparing the muscles for strengthening.
Building Strength and Stability
The rehabilitation progresses by introducing exercises that build muscle support around the joint, which is necessary for preventing re-injury and restoring functional capacity. This stage is divided into non-weight-bearing and weight-bearing exercises to gradually increase the load on the healing ligament. Strengthening the quadriceps, hamstrings, and glutes is paramount for stability.
Early Strengthening (Non-Weight Bearing/Partial Weight Bearing)
Early strengthening activities isolate the muscles without placing excessive strain on the joint. Straight Leg Raises, performed by lifting the straight leg in various directions (forward, side, and backward), target the hip flexors, quadriceps, and gluteal muscles. These exercises build baseline strength and control in a non-impact position.
Hamstring Curls are performed while lying on the stomach and bending the knee to lift the heel toward the ceiling, strengthening the muscles at the back of the thigh. Intensity can be increased by holding the contraction or slowly adding a light ankle weight (one to five pounds). The focus remains on slow, deliberate movements to ensure proper muscle activation and control.
Progressive Strengthening (Full Weight Bearing/Functional)
The next step integrates strength and coordination into functional, weight-bearing movements that mimic daily activities. Mini Squats are a starting point, involving a shallow bend of the knees while maintaining an upright posture. As strength improves, exercises like Step-Ups, where the injured leg steps up onto a small platform, introduce a controlled loading pattern that builds functional strength.
Wall Sits are an isometric exercise that requires holding a seated position against a wall, building endurance in the quadriceps and glutes. Balance and proprioception are trained through single-leg stands, initially on a firm surface and then progressing to unstable surfaces like a pillow. These exercises retrain the body’s awareness of the joint’s position in space, which is essential for dynamic stability and safe movement.
Criteria for Returning to Full Activity
A safe return to high-impact activities, sports, or full work duties requires meeting specific benchmarks to minimize the risk of re-injury.
- The knee must demonstrate a full, pain-free range of motion, bending and straightening completely without discomfort.
- Swelling should be completely resolved, and the joint must feel stable and secure during all movements.
- Strength testing should show the injured leg’s strength is nearly equal to the uninjured leg, aiming for a Limb Symmetry Index of over 90% to 95%.
- Functional tests, such as the ability to perform a single-leg hop or jump and land without pain, are important indicators of readiness.
If recovery stalls or the initial injury was severe, consulting with a physical therapist or physician is highly recommended for a personalized rehabilitation plan and final clearance.