BACKGROUND: The purpose of this single-examination pilot study was to confirm the ability to perform hip sonography while swaddled and to ascertain whether the various swaddling techniques influenced hip position and dynamics. METHODS: Dynamic sonography was used to evaluate 30 infants in both swaddled and unswaddled positions who were being seen in clinic for suspected or documented developmental dysplasia of the hip. A "treatment group" of 16 infants (32 hips) treated in a Pavlik harness and a "nontreatment group" of 14 untreated infants (28 hips) were studied.Criteria for comparing sonographic results between swaddled and unswaddled hip positions included femoral head position, instability, and range-of-motion restriction. RESULTS: Tight swaddling with a blanket was applied in 11 "nontreatment group" cases (20 hips; in 2 cases, only 1 hip studied) and produced limited flexion and abduction. One unstable left hip dislocated when tightly swaddled. Safe swaddling technique in 12 cases (24 hips) showed no limitation of flexion and abduction of the legs and no change in stability by sonography. Commercial swaddling products appeared to mildly restrict leg motion in 14 hips, but there was no change in hip position in the "nontreatment group." However, the commercial swaddling products changed the hip position in 3 Pavlik harness cases. CONCLUSIONS: Swaddling techniques that allow a free range of leg motion may not affect hip stability in normal infants or those being treated with Pavlik harness. Swaddling with restricted leg motion increases potential for hip instability. Tight swaddling dislocated 1 unstable hip, and commercial swaddling products judged to apply only mild restriction of leg motion negatively impacted 3 cases being treated for developmental dysplasia of the hip with Pavlik harness. On the basis of this pilot study, we advise caution when swaddling infants, especially with techniques that restrict leg motion. Further study of the long-term effects of swaddling is warranted. LEVEL OF EVIDENCE: Level II.
BACKGROUND: The purpose of this single-examination pilot study was to confirm the ability to perform hip sonography while swaddled and to ascertain whether the various swaddling techniques influenced hip position and dynamics. METHODS: Dynamic sonography was used to evaluate 30 infants in both swaddled and unswaddled positions who were being seen in clinic for suspected or documented developmental dysplasia of the hip. A "treatment group" of 16 infants (32 hips) treated in a Pavlik harness and a "nontreatment group" of 14 untreated infants (28 hips) were studied.Criteria for comparing sonographic results between swaddled and unswaddled hip positions included femoral head position, instability, and range-of-motion restriction. RESULTS: Tight swaddling with a blanket was applied in 11 "nontreatment group" cases (20 hips; in 2 cases, only 1 hip studied) and produced limited flexion and abduction. One unstable left hip dislocated when tightly swaddled. Safe swaddling technique in 12 cases (24 hips) showed no limitation of flexion and abduction of the legs and no change in stability by sonography. Commercial swaddling products appeared to mildly restrict leg motion in 14 hips, but there was no change in hip position in the "nontreatment group." However, the commercial swaddling products changed the hip position in 3 Pavlik harness cases. CONCLUSIONS: Swaddling techniques that allow a free range of leg motion may not affect hip stability in normal infants or those being treated with Pavlik harness. Swaddling with restricted leg motion increases potential for hip instability. Tight swaddling dislocated 1 unstable hip, and commercial swaddling products judged to apply only mild restriction of leg motion negatively impacted 3 cases being treated for developmental dysplasia of the hip with Pavlik harness. On the basis of this pilot study, we advise caution when swaddling infants, especially with techniques that restrict leg motion. Further study of the long-term effects of swaddling is warranted. LEVEL OF EVIDENCE: Level II.