Simultaneous pain in the hip and knee can be confusing because they are distinct joints. However, these two major joints are functionally linked, operating together in a complex system called the lower kinetic chain. Understanding these interconnected mechanics and shared pathways is the first step toward finding relief. Often, the true source of pain in one joint is actually a problem originating in the other.
The Biomechanical Connection and Referred Pain
The body’s lower half functions as a continuous kinetic chain. Altered movement or alignment in one area, such as the foot or pelvis, inevitably transfers stress and changes mechanics in the hip and knee. For instance, weak hip abductor muscles (like the gluteus medius) can fail to stabilize the pelvis during walking. This instability forces the thigh bone to rotate inward, placing abnormal stress on the knee joint, causing pain even though the primary issue lies at the hip.
This mechanical linkage often results in a change in gait as the body attempts to compensate for the primary source of pain. An abnormal walking pattern due to hip stiffness can cause the knee to absorb excessive forces, leading to secondary pain and degeneration. In this scenario, the knee pain is a symptom of the hip’s dysfunction, not a standalone injury.
A different mechanism linking the two joints is referred pain. This occurs when a sensory nerve pathway is irritated in one location, but the brain interprets the pain signal as coming from a distant site. For example, the femoral nerve innervates parts of both the hip and knee joints. Compression of nerve roots in the lumbar spine (L3 or L4 level) can cause pain that originates in the lower back but is felt in the hip or radiates down the inner thigh to the knee. Therefore, a spinal disc issue, not a knee problem, could be the actual cause of the knee pain.
Shared Joint Degeneration and Systemic Inflammation
Beyond mechanical connections, simultaneous hip and knee pain can be attributed to conditions that affect multiple joints throughout the body. Osteoarthritis (OA) is the most common form of joint degeneration, characterized by the breakdown of cartilage. While OA is often considered localized, advanced age and excess body weight place increased mechanical load on both the hips and knees. This often leads to the parallel development of OA in both weight-bearing joints.
Obesity is a specific factor linking both joints through mechanical stress and systemic inflammation. Adipose tissue (body fat) is metabolically active and secretes pro-inflammatory proteins called adipokines. This creates chronic, low-grade systemic inflammation throughout the body, which accelerates the degradation of cartilage and joint tissue in both the hip and knee.
Inflammatory conditions, such as Rheumatoid Arthritis (RA) or Psoriatic Arthritis, are systemic autoimmune diseases. They cause the immune system to mistakenly attack the joint lining. Since these conditions affect the entire body, they frequently cause inflammation and pain in multiple joints concurrently. The symmetrical nature of the joint damage in these systemic diseases explains why both the hip and knee become painful simultaneously.
Nerve Compression and Soft Tissue Involvement
Specific structures spanning the distance between the hip and knee can also cause simultaneous discomfort. The iliotibial (IT) band is a thick strip of connective tissue running along the outside of the thigh, from the hip to just below the knee. When this band becomes tight or inflamed (IT Band Syndrome), it can cause friction-related pain at its upper attachment near the hip (greater trochanteric bursitis) and at its lower end near the knee.
Nerve compression is another common culprit that creates a continuous path of pain. Sciatica involves the irritation or compression of the sciatic nerve, which runs from the lower back through the hip and down the back of the leg. This irritation causes radiating pain, numbness, or tingling that begins in the buttock or hip and travels down the thigh, sometimes extending to the knee. The pain is caused by the nerve pathway connecting the regions, not by a problem in the knee joint itself.
The muscle groups surrounding the hip and knee also contribute to soft tissue involvement. Tightness or trigger points in the hip flexors or hamstrings can alter the biomechanics of both joints, leading to secondary inflammation and pain. For example, a tight hip flexor can cause an anterior pelvic tilt, which causes the knee to hyperextend slightly. This increases strain on local soft tissues, resulting in pain in both the hip and knee.
When to Seek Professional Guidance
While many causes of hip and knee pain improve with rest, certain symptoms require professional medical evaluation.
Urgent Symptoms
Sudden, severe pain that makes it impossible to bear weight on the affected leg is a significant warning sign, suggesting a fracture or acute soft tissue tear. Pain accompanied by systemic symptoms, such as an unexplained fever, chills, or significant warmth and redness around the joint, requires urgent medical attention to rule out a joint infection.
Non-Urgent but Necessary Evaluation
If the joint feels unstable, locks, or gives way during movement, it suggests a mechanical issue like a meniscal tear or ligament damage that needs assessment. Persistent pain that does not improve after a couple of weeks of at-home care, or pain that consistently disrupts sleep, also signals that a precise diagnosis is necessary.