Bone-on-Bone Knees: Why Swimming is Excellent for Osteoarthritis Pain and Mobility

Is swimming good for bone on bone knees?

Yes, swimming is generally considered an excellent exercise for individuals with "bone on bone" knees, a common term for severe knee osteoarthritis, due to its low-impact nature and the supportive properties of water.

Understanding "Bone-on-Bone" Knees (Severe Osteoarthritis)

"Bone-on-bone" knees refer to an advanced stage of osteoarthritis (OA), a degenerative joint disease characterized by the breakdown of cartilage that cushions the ends of bones. In severe cases, this protective cartilage erodes almost completely, leading to direct friction between the bones of the thigh (femur) and shin (tibia), causing significant pain, stiffness, swelling, and reduced mobility. Weight-bearing activities often exacerbate these symptoms, as they place direct compressive loads on the compromised joint.

The Unique Benefits of Swimming for Knee Osteoarthritis

Swimming offers a unique set of advantages for managing the symptoms of severe knee osteoarthritis, primarily by creating an environment that minimizes joint stress while promoting physical activity.

• Reduced Joint Loading: The most significant benefit of water-based exercise is buoyancy. Water supports a large percentage of body weight, significantly reducing the compressive forces on the knee joint that are typically experienced during land-based activities like walking, running, or jumping. This allows for movement with less pain and stress.
• Improved Range of Motion: The warm water often found in pools can help relax muscles and increase blood flow, making it easier to move the knee through a greater range of motion without the friction and pain associated with direct weight-bearing. Consistent, gentle movement helps to maintain joint flexibility and prevent further stiffness.
• Muscle Strengthening without Impact: While buoyancy reduces weight-bearing, water still provides natural resistance to movement. This resistance allows for effective strengthening of the muscles surrounding the knee—including the quadriceps, hamstrings, and calves—without the high impact that could aggravate the joint. Stronger muscles provide better support and stability for the knee, potentially reducing pain and improving function.
• Cardiovascular Health: Swimming is a fantastic full-body cardiovascular workout. Improving cardiovascular health is crucial for overall well-being and can indirectly support joint health by improving circulation and aiding in weight management, which further reduces stress on the knees.
• Pain Relief: The combination of reduced load, improved muscle support, and the gentle, rhythmic motion of swimming can lead to significant pain relief for many individuals with knee OA. The warm water itself can also have a soothing, analgesic effect.

Biomechanical Considerations and Why Swimming Works

The principles of fluid dynamics and biomechanics explain why swimming is so beneficial:

• Buoyancy's Role: According to Archimedes' principle, an object submerged in a fluid experiences an upward buoyant force equal to the weight of the fluid displaced. For humans, this means that when submerged to the neck, approximately 90% of body weight is supported by the water, drastically reducing the load on lower extremity joints.
• Hydrostatic Pressure: The pressure exerted by water on the body (hydrostatic pressure) can help reduce swelling and improve circulation, further contributing to pain relief and tissue health around the joint.
• Viscous Drag: Water's viscosity provides a consistent, concentric and eccentric resistance throughout the entire range of motion, allowing for controlled muscle strengthening without the acceleration/deceleration forces common in land-based exercises that can be jarring to compromised joints.

Recommended Swimming Styles and Modifications

While swimming is generally beneficial, certain strokes or modifications may be more appropriate for individuals with bone-on-bone knees:

• Freestyle (Front Crawl): Often the most comfortable stroke, as the flutter kick is relatively small and continuous, placing minimal stress on the knee joint.
• Backstroke: Similar to freestyle, the backstroke uses a flutter kick that is gentle on the knees.
• Avoid Aggressive Breaststroke Kick: The "whip kick" or "frog kick" of the breaststroke involves significant external rotation and flexion of the knee, which can exacerbate pain and stress the medial (inner) compartment of the knee, where OA is often most severe. If breaststroke is preferred, a modified, narrower kick or a gentle flutter kick can be used.
• Aqua Jogging/Walking: For those who prefer upright movement, walking or jogging in deep water (with or without a flotation belt) provides the benefits of weight-bearing exercise without the impact.
• Utilize Aquatic Aids: Kickboards, pull buoys, and noodles can be used to isolate upper body strengthening or provide additional flotation, allowing for varied exercises and reduced knee strain.

Potential Limitations and Precautions

While highly beneficial, swimming is not a universal panacea, and certain considerations are important:

• Individual Variability: The severity of OA and individual pain tolerance vary. What is comfortable for one person may not be for another.
• Water Temperature: Some individuals may find very cold water exacerbates joint stiffness. Warmer pools (e.g., therapy pools) may be more comfortable.
• Access and Mobility: Getting in and out of the pool can be challenging for those with significant mobility issues. Ramps, hydraulic lifts, or shallow entry points are helpful.
• Not a Cure: Swimming helps manage symptoms and improve function, but it does not reverse the cartilage damage of osteoarthritis. It should be part of a broader management strategy.

Integrating Swimming into a Comprehensive Management Plan

For optimal results, swimming should be integrated into a holistic management plan for knee osteoarthritis. This plan often includes:

• Consultation with Healthcare Professionals: Always consult with a physician, physical therapist, or exercise physiologist before starting a new exercise program, especially with severe joint conditions. They can provide personalized recommendations and ensure the program is safe and effective.
• Physical Therapy: Targeted exercises to improve strength, flexibility, and balance are crucial.
• Strength Training: Land-based, non-impact strength training (e.g., using resistance bands or machines) for surrounding muscles, as tolerated, complements aquatic exercise.
• Weight Management: Reducing excess body weight significantly decreases the load on knee joints.
• Pain Management Strategies: This may include medication, injections, or other non-pharmacological approaches.

Conclusion

Swimming stands out as an exceptionally beneficial exercise for individuals experiencing "bone on bone" knees due to severe osteoarthritis. Its low-impact nature, combined with the buoyancy and resistance of water, effectively reduces joint stress, alleviates pain, improves range of motion, and strengthens supporting musculature. When performed with appropriate modifications and as part of a comprehensive, professionally guided management plan, swimming can significantly enhance quality of life and functional capacity for those living with advanced knee osteoarthritis.