COVID-19 is primarily known as a respiratory illness, but the SARS-CoV-2 infection is systemic, affecting multiple organ systems. Musculoskeletal symptoms, including muscle pain (myalgia) and joint pain (arthralgia), are commonly reported during the acute phase and can persist afterward. COVID-19 can cause hip pain through several distinct mechanisms, ranging from temporary muscle aches to more serious, delayed joint complications. This pain results from the body’s immune response and, in some cases, the treatments used to manage severe illness.
The Acute Connection to Muscle and Joint Pain
Acute hip pain during the initial infection is often a manifestation of widespread muscle aches (myalgia), affecting up to 86% of people with a COVID-19 diagnosis. The pain is typically felt in the large muscle groups surrounding the hip and upper leg, rather than being localized to the joint itself. This type of body ache is common in many acute viral infections, including influenza.
The immune system’s immediate reaction involves releasing inflammatory signaling molecules called cytokines. These cytokines circulate throughout the body, triggering pain receptors and causing inflammation within muscle tissue. Since the hip is a major weight-bearing joint surrounded by large muscles, it is particularly susceptible to the generalized aches and tenderness characteristic of this initial viral stage.
Systemic Inflammation and Musculoskeletal Effects
Beyond the initial muscle aches, the body’s systemic inflammatory response can cause specific joint issues, including in the hip. In severe COVID-19 cases, this response can escalate into a “cytokine storm,” characterized by an excessive release of pro-inflammatory molecules such as Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-α).
These inflammatory molecules can target the joint linings, causing synovitis. Inflammation of the synovial tissue in the hip joint leads to pain, swelling, and reduced range of motion. The SARS-CoV-2 virus may also directly infect cells within the musculoskeletal system, including synovial tissue, because these cells express the ACE2 receptor used by the virus to enter the body.
The resulting inflammation can lead to post-infectious or reactive arthritis. In this condition, the immune system mistakenly targets the body’s own joint tissues after fighting the virus. This reactive process is a recognized cause of joint pain that can start weeks after the initial infection has cleared, often affecting weight-bearing joints like the hip.
Delayed and Long COVID Musculoskeletal Issues
Hip pain persisting for weeks or months after recovery is referred to as post-COVID-19 arthralgia, falling under the umbrella of Long COVID. This chronic joint pain is reported by many Long COVID patients and can limit mobility and daily function. The cause is likely persistent, low-grade systemic inflammation or a lingering autoimmune response.
A more serious, though rarer, delayed complication is Avascular Necrosis (AVN), particularly affecting the femoral head (the ball portion of the hip joint). AVN, or osteonecrosis, involves the death of bone tissue due to an interruption in blood supply. This condition is a known risk associated with high-dose corticosteroid medications, such as dexamethasone, often used to treat severe COVID-19 lung inflammation.
While steroids are life-saving in many severe COVID-19 cases, they can disrupt blood flow to the bone, potentially leading to the collapse of the femoral head over time. AVN has been reported to develop rapidly post-COVID-19, with bilateral hip pain appearing within months of steroid treatment. The COVID-19 infection itself may also contribute to AVN development by causing small blood clots or increasing the risk of blood vessel damage.
When Hip Pain Requires Medical Evaluation
While most acute COVID-related aches resolve within a few weeks, certain hip pain symptoms warrant prompt medical attention. Seek immediate evaluation if the pain is sudden and severe, or if it prevents you from bearing weight on the affected leg. This is also necessary if the pain is accompanied by a fever after the initial infection has passed, which could indicate an acute joint infection.
Persistent hip pain that does not improve after several weeks, or pain that progressively worsens, requires consultation with a healthcare provider. Individuals treated with high-dose corticosteroids for severe COVID-19 should be vigilant for new or increasing hip or groin pain, which can be an early sign of Avascular Necrosis. Early diagnosis of AVN, often via MRI, is necessary to preserve the joint.