Adhesive capsulitis of the hip, commonly known as frozen hip, causes significant pain and profound restriction in hip joint movement. Characterized by inflammation and progressive loss of mobility, frozen hip is a relatively rare condition compared to the more widely recognized frozen shoulder. Individuals often seek answers because the stiffness and discomfort feel distinctly different from common aches or strains. This pathology leads to a feeling of the hip being rigidly locked, impacting simple daily motions and causing disability.
The Physical Mechanism of Restricted Movement
The sensation of a “frozen” hip results from physical changes within the hip joint’s fibrous capsule. This strong, sleeve-like structure surrounds the ball-and-socket joint, holding the bones together. The process, Adhesive Capsulitis, begins with inflammation of the joint’s lining, the synovial membrane.
As the condition progresses, the inflamed capsule thickens and contracts, known as capsular fibrosis. This thickening is caused by the formation of scar tissue, or adhesions, within the capsule folds. These adhesions physically shrink the available space, tethering the femur’s ball to the pelvis’s socket. The resulting restriction is mechanical, meaning the hip physically cannot move past a certain point because the surrounding tissue has tightened and shortened.
Describing the Stages of Frozen Hip
The feeling of a frozen hip evolves over a predictable course divided into three distinct phases. The initial experience is dominated by pain, which gradually gives way to stiffness.
Phase 1: Freezing (Painful Stage)
The Freezing phase is characterized by a gradual increase in pain, which is the dominant symptom. This pain is often described as a deep, constant ache felt in the groin, buttocks, or outer hip. Sharp pain may occur with sudden movements, especially when rotating the leg outwards. The discomfort is frequently worse at night, disrupting sleep as inflammation within the joint capsule intensifies. Stiffness is present but is overshadowed by the pain, making the initial complaint centered on soreness rather than immobility.
Phase 2: Frozen (Stiff Stage)
As the condition advances into the Frozen phase, the experience shifts dramatically. The constant, intense pain often subsides, but the hip’s mobility becomes severely limited. The hip feels rigidly locked, and the restriction is so profound that simple tasks become nearly impossible. Movements like putting on socks, getting into a car, or pivoting the body are hampered by the stiffness. The hip’s range of motion is restricted in almost every direction, leading to a sensation that the joint is cemented in place.
Phase 3: Thawing (Recovery Stage)
The Thawing phase marks the slow, gradual return of movement and a continued decrease in pain. This stage is experienced as a loosening of the rigid restriction that defined the Frozen phase. The feeling of being locked up diminishes, and the person slowly regains the ability to perform everyday activities. While recovery is often incomplete, the overall sensation is one of progressive improvement. The duration of the entire cycle, from freezing to thawing, can last anywhere from one to three years.
Distinguishing Frozen Hip from Other Pain
Frozen hip presents a pattern of restriction that helps differentiate it from more common hip issues like osteoarthritis or bursitis. The location and quality of the pain, along with the movement limitation, are the key distinguishing factors. Osteoarthritis pain typically manifests as a deep, dull ache in the groin or front of the thigh, often accompanied by morning stiffness that improves with activity. In contrast, trochanteric bursitis causes a sharp pain located on the outer side of the hip, which is highly tender to the touch and often worsens when lying on that side. The pain from frozen hip may be more diffuse, spreading across the groin and buttocks, but the defining feature is the severe loss of movement.
The most characteristic sign of adhesive capsulitis is the global limitation of both active and passive range of motion. Active motion is when a person moves their own leg, while passive motion is when someone else moves the leg. In frozen hip, the limitation is the same in both scenarios, especially a profound restriction of internal and external rotation, indicating a physical barrier within the capsule itself. This symmetrical restriction across all planes of movement is what sets frozen hip apart from conditions where the stiffness may only be due to muscle spasm.