Child and Young Adult Hip Preservation Program | Hip Glossary

LIke ThisLIke ThisLIke ThisLIke ThisLIke This

Contact the Child and Young Adult Hip Preservation Program

  • 617-355-6021
  • International: +1-617-355-5209
  • Locations

This reference guide provides definitions for common health terms that you may hear when your child is being treated for a hip related condition. Many terms also have links to additional information on this website. Feel free to ask your child’s doctor, nurse or any of our staff members for further information regarding any term you may still be unfamiliar with. For additional resources, visit our orthopedic glossary.

A-C     D-F    G-I     J-L    M-O    P-R    S-T     U-Z


Movement of a limb or body part away from the midline of your body

The cup-shaped socket of the hip joint

Adaptive equipment
Equipment that supports a child's positioning needs, such as seating, standing, positioning and mobility, or assists with function

The inward movement of an arm or leg toward the body

Arthritis (osteoarthritis)
Joint inflammation, resulting in pain, swelling, stiffness and limited movement

Articular cartilage
Connective tissue that reduces friction between bony surfaces; found on the surfaces of bones within joints

Weakening of muscle tissues from lack of use

Avascular necrosis (AVN)
A disease caused by the temporary or permanent loss of blood supply to bones; bone lacking blood can collapse and die


Bernese periacetabular osteotomy
Boston Children’s standard treatment for a hip socket that’s too shallow in a patient whose socket has finished growing—typically at ages 13 or 14 through adult—and whose hip is still viable enough to be repaired rather than replaced. It’s the most complex and powerful procedure for repositioning the hip socket

Relating to both sides of the body

Bone graft
Pieces of bone used to create fusion. Bone graft may be obtained from the patient's iliac crest, rib, wrist, or from the bone bank

Bone remodeling
The absorption of bone tissue and the simultaneous depositing of new bone; a bone’s continuous self-renewal, self-healing and self-realignment, partially through reorientation of the growth plate. In kids’ fractures, the bone’s remodeling capability is usually very good, so poor alignment (mal-union)is rare


Smooth, rubbery tissue that cushions the bones of a joint and other areas; allows the bones to move easily without pain

External devices used to hold a bones of the hip joint in place while they develop in proper position

Closed reduction procedure/surgery
A procedure in which the doctor repositions the hip bone into the socket from outside the patient’s body, and holds it in place with a harness or cast

Computed tomography (CT, CAT) scan
A non-invasive procedure that uses X-ray equipment and powerful computers to create detailed, cross-sectional images of your child’s body. The CT scanner is a large machine that looks like a big doughnut


Developmental dysplasia of the hip (DDH, hip dysplasia)
A spectrum of hip abnormality—ranging from a minor laxity of the ligament that holds the ball in the socket to a complete dislocation, in which the ball is entirely out of the socket

Diagnosis, diagnostics
Identifying disease or injury through examination, testing and observation

A dislocation occurs when extreme force is put on a joint, allowing the ends of two connected bones to separate 

An abnormal development of tissue; an alteration in the size, shape, and/or organization of cells or tissues 


Femoral head
Round-headed top of the thigh bone (femur)

The thigh bone, the longest and strongest of your child’s bones. The rounded top of the femur (femoral head) joins the hip socket (acetabulum) to form the hip joint


Growth disturbance
A fracture that extends into the bone’s growth plates in still-growing children can disturb or stop the normal growth of the bone (growth arrest). This can lead to limb length discrepancies or angular deformities. Surgery on broken limbs in children must account for these growth plates

Growth plate (physis)
Areas of cartilage at either end of a bone from which growth occurs. As key components of a child’s developing skeletal system, growth plates largely turns to bone (ossify) as a child grows


Hip impingement
A condition in which the femoral head doesn't have a full range of motion within the acetabulum; caused by too much bone around the head and/or the socket turned backwards; causes pain and can result in damage to the cartilage and labrum 


Iliac crest
The large flat portion of the pelvis bone from which bone graft may be taken

Internal fixation
Metal screws and pins surgically inserted inside the bone to hold bone fragments in place to allow alignment and healing


Sheet or band of fibrous connective tissue that connects bones or cartilages, either at a joint or in support of an organ


Maldevelopment (dysplasticity)
Condition in which a bone or joint is not properly developed/developing

Mal-union (mal-alignment)
A condition in which a broken bone heals in a poor alignment or a deformed state (such as an angular deformity); rare in children

MRI (magnetic resonance imaging)
Produces detailed images of organs and structures within the body; best for looking at soft/non-bone tissues such as ligaments, tendons, muscle, and cartilage


Non-surgical (non-operative) treatments
Alternatives to surgery


Open reduction surgery
A procedure in which the doctor repositions the hip bone into the socket through an incision into the patient’s body

Orthopedic surgeon, orthopedist
A doctor who specializes in surgical and non-surgical treatment of the skeletal system, spine and associated muscles, joints and ligaments

The medical specialty concerned with diagnosing, treating, rehabilitating and preventing disorders and injuries to the spine, skeletal system and associated muscles, joints and ligaments

A type of arthritis caused by the inflammation, breakdown, and eventual loss of articular cartilage in the joints

Destruction of bone caused by disease, infection or loss of blood supply 

An outgrowth of bone which forms around the joints, deforming the joints and limiting their movements; commonly found in joints with osteoarthritis

A surgical procedure in which bones are cut and re-orientated, with the goal of improving function


The mechanical forces of a disease that adversely change the body's structure and function

Pavlik harness
A type of brace used on infants to improve the position of the femoral head in the acetabulum

Periacetabular osteotomy (PAO)
A type of surgery in which the bones surrounding the acetabulum are cut and repositioned in order to better align the femoral head within the acetabulum

Perthes disease
A condition in which the femoral head dies because of a temporary loss of blood supply to it

Physeal fracture
A break that occurs at, into or across a growth plate; must be treated promptly to avoid growth disturbance or deformity

Physical therapy
A rehabilitative health specialty that uses therapeutic exercises and equipment to help patients improve or regain muscle strength, mobility and other physical capabilities

Physis, physes
A growth plate(s) at both ends of a bone; the source of bone growth

Post-operative (post-op)
After surgery

Pre-operative (pre-op)
Before surgery


Skeletally immature
In pre-pubescent or early-adolescent children, the bones of the skeleton haven’t yet fully grown

Slipped capital femoral epiphysis (SCFE)
A condition in which the growing end of the femur slips off from the rest of the femur


Total joint replacement
A surgery done to replace a worn out joint

A sustained mechanical pull to a limb to correct a dislocation or broken bone


A non-invasive diagnostic imaging tool. Ultrasound is an imaging technology that uses high frequency sound waves to view internal organs and produce diagnostic pictures of the body


Diagnostic radiology that shows the dense structures, including bones, inside your child’s body 

Boston Children’s is so much more than a hospital—it’s a community of researchers, clinicians, administrators, support staff, innovators, teachers, patients and families, all working together to make the impossible possible. ”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital
300 Longwood Avenue, Boston, MA 02115
For Patients: 617-355-6000
For Referring Providers: 844-BCH-PEDS | 844-224-7337