hip dysplasia hip dysplasia hip dysplasia is an abnormality of the hip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk for joint dislocation. hip dysplasia may occur at birth or develop in early life. regardless, it does not typically produce symptoms in babies less than a year old. occasionally one leg may be shorter than the other. the left hip is more often affected than the right. complications without treatment can include arthritis, limping, and low back pain. females are affected more often than males. risk factors for hip dysplasia include female sex, family history, certain swaddling practices, and breech presentation whether an infant is delivered vaginally or by cesarean section. if one identical twin is affected, there is a 40% risk the other will also be affected. screening all babies for the condition by physical examination is recommended. ultrasonography may also be useful. hip dysplasiaother namesdevelopmental dysplasia of the hip (ddh), developmental dislocation of the hip, congenital dysplasia of the hip (cdh)congenital dislocation of the left hip in an elderly person. closed arrow marks the acetabulum, open arrow the femoral head.specialtypediatrics, orthopedicssymptomsnone, hip aches, one leg shorter, limpingcomplicationsarthritisrisk factorsfamily history, swaddling, breech birthdiagnostic methodphysical exam, ultrasoundtreatmentbracing, casting, surgeryprognosisgood (if detected early)frequency1 in 1,000 (term babies) many of those with mild instability resolve without specific treatment. in more significant cases, if detected early, bracing may be all that is required. in cases that are detected later, surgery and casting may be needed. about 7.5% of hip replacements are done to treat problems which have arisen from hip dysplasia. about 1 in 1,000 babies have hip dysplasia. hip instability of meaningful importance occurs in one to two percent of babies born at term. females are affected more often than males. hip dysplasia was described at least as early as the 300s bc by hippocrates. signs and symptoms types of misalignments of femur head to socket in hip dysplasia. a: normal. b: dysplasia. c: subluxation. d: luxation hip dysplasia can range from barely detectable to severely malformed or dislocated. the congenital form, teratologic or non-reducible dislocation occurs as part of more complex conditions. the condition can be bilateral or unilateral: if both hip joints are affected, one speaks of "bilateral" dysplasia. in this case, some diagnostic indicators like asymmetric folds and leg-length inequality do not apply. in unilateral dysplasia only one joint shows deformity, the opposite side may show resulting effects. in the majority of unilateral cases, the left hip has the dysplasia. if the joint is fully dislocated a false acetabulum often forms (often higher up on the pelvis) opposite the dislocated femoral head position. in acetabular dysplasia, the acetabulum (socket) is too shallow or deformed. the center-edge angle is measured as described by wiberg. two forms of femoral dysplasia are coxa vara, in which the femur head grows at too narrow an angle to the shaft, and coxa valga, in which the angle is too wide. a rare type, the "beukes familial hip dysplasia" is found among afrikaners that are members of the beukes family. the femur head is flat and irregular. people develop osteoarthritis at an early age. causes hip dysplasia is considered to be a multifactorial condition. that means that several factors are involved in causing the condition to manifest. the cause of the condition is unknown; however, some factors of congenital hip dislocation are through heredity and racial background. it is also thought that the higher rates in some ethnic groups (such as some native american groups) is due to the practice of swaddling of infants, which is known to be a potential risk factor for developing dysplasia. it also has a low risk in african americans and southern chinese. congenital some studies suggest a hormonal link. specifically, the hormone relaxin has been indicated. female sex, alone without other known risk factors, accounts for 75%. a genetic factor is indicated since the trait runs in families and there is an increased occurrence in some ethnic populations (e.g., native americans, lapps / sami people). a locus has been described on chromosome 13. beukes familial dysplasia, on the other hand, was found to map to an 11-cm region on chromosome 4q35, with nonpenetrant carriers not affected. further risk factors include , gender, genetics (family history), and firstborns. acquired in the breech position the femoral head tends to get pushed out of the socket and the breech position is probably the most important single risk factor, whether an infant is delivered vaginally or by cesarean section. as an acquired condition it has been linked to traditions of swaddling infants, use of overly restrictive baby seats, carriers and other methods of transporting babies, or use of a cradle board which locks the hip joint in an "adducted" position (pulling the knees together tends to pull the heads of the femur bone out of the sockets or acetabulae) for extended periods. modern swaddling techniques, such as the 'hip healthy swaddle' have been developed to relieve stress on hip joints caused by traditional swaddling methods. a narrow uterus also facilitates hip joint dislocation during fetal development and birth. diagnosis α and β angles used in hip ultrasound hip ultrasound x-ray image showing hip dysplasia in a baby the screening examination techniques to detect hip dysplasia in newborns include observation for asymmetry of legs and asymmetrical gluteal folds , limb length discrepancy (evaluated by placing the child in a supine position with the hips and knees flexed ), and restricted hip abduction. sometimes during an exam a "click" or more precisely "clunk" in the hip may be detected (although not all clicks indicate hip dysplasia). when a hip click (also known as "clicky hips" in the uk) is detected, the child's hips are tracked with additional screenings to determine if developmental dysplasia of the hip is caused. two maneuvers commonly employed for diagnosis in neonatal exams are the ortolani maneuver and the barlow maneuver. in order to do the ortolani maneuver it is recommended that the examiner put the newborn baby in a position in which the opposite hip is held still while the thigh of the hip being tested is abducted and gently pulled anteriorly. if a "clunk" is heard (the sound of the femoral head moving over the acetabulum), the joint is normal, but absence of the "clunk" sound indicates that the acetabulum is not fully developed. the next method that can be used is called the barlow maneuver. it is done by adducting the hip while pushing the thigh posteriorly. if the hip goes out of the socket it means it is dislocated, and the newborn has a congenital hip dislocation. the baby is laid on its back for examination by separation of its legs. if a clicking sound can be heard, it indicates that the baby may have a dislocated hip. it is highly recommended that these maneuvers be done when the baby is not fussing, because the baby may inhibit hip movement. most vexingly, many newborn hips show a certain ligamentous laxity, on the other hand severely malformed joints can appear stable. that is one reason why follow-up exams and developmental monitoring are important. physical examination of newborns followed by appropriate use of hip ultrasound is widely accepted. the harris hip score (developed by william h. harris md, an orthopedist from massachusetts) is one way to evaluate hip function following surgery. other scoring methods are based on patients' evaluation like e.g. the oxford hip score, hoos and womac score. children's hospital oakland hip evaluation scale (chohes) is a modification of the harris hip score that is currently being evaluated. hip dysplasia can develop in older age. adolescents and adults with hip dysplasia may present with a waddling gait, trendelenburg's sign, decreased hip abduction, hip pain and in some cases hip labral tears. x-rays are used to confirm a diagnosis of hip dysplasia. ct scans and mri scans are occasionally used too. terminology some sources prefer "developmental dysplasia of the hip" (ddh) to "congenital dislocation of the hip" (cdh), finding the latter term insufficiently flexible in describing the diversity of potential complications. the use of the word congenital can also imply that the condition already exists at birth. this terminology introduces challenges, because the joint in a newborn is formed from cartilage and is still malleable, making the onset difficult to ascertain. the newer term ddh also encompasses occult dysplasia (e.g. an underdeveloped joint) without dislocation and a dislocation developing after the "newborn" phase. the term is not used consistently. in pediatric/neonatal orthopedics it is used to describe unstable/dislocatable hips and poorly developed acetabula. for adults it describes hips showing abnormal femur head or acetabular x-rays. some sources prefer the term "hip dysplasia" over ddh, considering it to be "simpler and more accurate", partly because of the redundancy created by the use of the terms developmental and dysplasia. types of ddh include subluxation, dysplasia, and dislocation. the main types are the result of either laxity of the supporting capsule or an abnormal acetabulum. imaging