Range of motion (ROM) describes the total distance and direction a joint can travel. This measurement is typically expressed in degrees. Limited range of motion (LROM) occurs when a joint has a reduction in its normal ability to move through this expected angular distance. LROM affects everyday activities, making simple tasks like reaching or walking difficult, and often signals an underlying structural, inflammatory, or neurological issue impeding normal joint function.
Understanding Normal and Limited Joint Movement
The assessment of joint mobility distinguishes between two main types of movement: active and passive range of motion. Active range of motion (AROM) refers to the movement a person can generate using only their own muscles, without external help. This self-initiated movement demonstrates the functional capacity of the muscles and nerves controlling the joint.
Passive range of motion (PROM) is the distance a joint can be moved when an outside force, such as a physical therapist, is applied while the person remains relaxed. PROM often reveals the maximum potential flexibility of the joint’s non-contractile structures, like ligaments and the joint capsule.
When AROM is limited but PROM remains full, the issue often points toward muscle weakness or a nerve problem preventing effective muscle contraction. If both AROM and PROM are limited, it typically indicates a physical restriction within the joint itself, such as stiff scar tissue or bony changes. A large difference between the two measurements suggests a lack of muscular control over the available range, which is a common focus in rehabilitation efforts.
Primary Physical Causes of Restriction
Limited range of motion arises from various physical issues grouped into structural, inflammatory, and neuromuscular categories.
Structural Restrictions
Structural restrictions involve physical damage to joint components that directly block motion. Examples include the formation of bone spurs (osteophytes) seen in osteoarthritis, or the presence of loose bodies of cartilage or bone fragments lodged within the joint space.
Inflammatory and Soft Tissue Causes
Inflammatory and soft tissue causes involve the non-bony structures surrounding the joint. Acute injuries or chronic conditions can lead to swelling and the formation of fibrotic scar tissue, which stiffens the joint capsule. Adhesive capsulitis, or “frozen shoulder,” is a clear example where the shoulder capsule thickens and contracts, severely restricting movement in all directions.
Neuromuscular Causes
Neuromuscular causes originate from the brain, spinal cord, or peripheral nerves, preventing muscles from moving the joint correctly. Conditions like stroke or cerebral palsy disrupt nerve signals, leading to muscle weakness or spasticity that involuntarily restricts movement.
Recognizing the Signs of Limited Motion
LROM is perceived as noticeable stiffness or tightness in a joint that makes movement feel restricted. Individuals frequently experience pain when attempting to move the joint past a certain point, a protective mechanism known as muscle guarding. This discomfort serves as a primary signal that the joint is nearing its restricted end range.
The restriction manifests as significant functional impairment, causing difficulty performing routine daily activities. For example, shoulder LROM makes it hard to reach overhead, while hip or knee limitations impede walking, climbing stairs, or bending down. Over time, disuse of the affected joint can lead to muscle atrophy and further weakness in the surrounding area.
Clinical Assessment and Treatment Overview
Clinical assessment of LROM begins with a physical examination where a healthcare provider observes the joint’s movement. Physical therapists use a specialized tool called a goniometer to accurately measure the angle of movement in degrees, comparing results to established normal values. Imaging tests, such as X-rays, may also be used to identify structural causes like fractures or arthritic changes within the joint.
Management of LROM often starts with conservative treatment. Physical therapy is a cornerstone of care, involving targeted stretching and mobilization techniques to increase joint flexibility. Strengthening exercises improve muscle control over the newly gained range. Medications such as non-steroidal anti-inflammatory drugs (NSAIDs) help reduce the pain and inflammation contributing to the restriction.
For severe or persistent cases, advanced interventions may be necessary. These include joint injections of corticosteroids to reduce localized inflammation. When structural damage is significant, surgical options may be explored. Procedures range from minimally invasive techniques to release scar tissue to extensive operations like joint replacement, aiming to restore the joint’s mechanical function.