Overview
Closed reduction for developmental dysplasia of the hip aims to obtain a stable, concentric relationship between the femoral head and acetabulum without compromising femoral head perfusion. A palpable reduction alone is insufficient: stability, arthrographic seating and the position required to retain reduction must all be assessed. Reduction should never be maintained at the cost of extreme abduction or rotation (Tachdjian, Chapter 13).
Indications and Planning
Use a treatment plan appropriate to the child's age, previous brace treatment, hip reducibility and acetabular development. Closed reduction and casting are considered when a dislocated hip cannot be managed successfully by the preceding nonoperative pathway.
Confirm that the hip is developmentally dislocated rather than a different congenital or neuromuscular problem. Review current imaging and prior treatment.
Do not postpone otherwise indicated treatment solely to wait for the femoral head ossific nucleus; the source emphasizes declining acetabular remodeling potential with age.
Explain the possibility of adductor release, failure of closed reduction, open reduction and further surgery for residual dysplasia.
Pre-reduction traction is not an obligatory step. Tachdjian describes conflicting historical evidence and does not establish a reliable reduction in osteonecrosis from routine traction.
(Tachdjian, Chapter 13.)
Positioning and Setup
Perform the reduction under general anesthesia in a setting equipped for fluoroscopy, arthrography and safe spica application.
Ensure that an experienced assistant can hold the selected hip position during casting.
Have a clear plan for assessment of reduction after cast application, using the imaging method available and appropriate for the child.
Prepare for a change in strategy if a stable, adequately seated hip cannot be maintained in a physiologic position.
(Tachdjian, Chapter 13.)
Surgical Technique
Gentle Reduction
Examine the hip under anesthesia and assess its available motion without force.
Flex the hip beyond 90 degrees and gradually abduct it while gently lifting the greater trochanter, as in a controlled Ortolani maneuver.
Use minimal force. After the femoral head reduces, maintain gentle support and determine whether it stays reduced without continual pressure.
Do not repeatedly force an unstable or irreducible head against the acetabular entrance. If reduction cannot be maintained safely, reassess the obstacles and the indication for open reduction.
(Tachdjian, Chapter 13.)
Define the Safe Zone
With the hip flexed and reduced, gradually adduct to identify the position at which it redislocates.
Reduce again and assess the extension position at which stability is lost.
Note whether internal rotation is needed to maintain reduction and compare the stable arc with the child's total available motion.
A broad stable range supports closed treatment. Stability only at extreme abduction or with more than approximately 10–15 degrees of internal rotation is unfavorable in the source's assessment.
If adductor tightness is limiting the safe zone, an adductor tenotomy may improve the available range. It does not justify casting the hip at maximal abduction.
(Tachdjian, Chapter 13, Ramsey safe-zone assessment.)
Arthrographic Assessment
Obtain dynamic views to assess the depth of reduction, labrum, capsular constriction, medial contrast pool and positions of stability or redislocation. Interpret the arthrogram together with the clinical feel and safe zone (Tachdjian, Chapter 13).
Source description | Interpretation |
|---|---|
Narrow medial rim of contrast | Supports a well-seated, stable reduction. |
Approximately 5–6-mm medial pool with easy maintenance | Classified as a fair reduction in the source; requires the full stability and imaging assessment. |
Medial pool wider than 6 mm with difficulty maintaining reduction | Unfavorable seating and stability; reassess the need for open reduction. |
Labral interposition or marked capsular constriction | May prevent concentric seating even if a reduction maneuver produces an apparent clunk. |
Tachdjian explicitly describes disagreement about accepting a stable but initially widened reduction: some authors require essentially concentric seating, while others accept selected stable hips that seat more deeply during immobilization. A single contrast-pool measurement should not replace expert interpretation of the entire reduction.
Spica Application
Choose a position within the demonstrated stable zone, avoiding its extremes.
The source generally uses more than 90 degrees of flexion and moderate abduction, commonly about 30–40 degrees when further abduction remains available.
Use only limited internal rotation if necessary. Do not place the hip at its maximal abduction or internal rotation limit.
Have an experienced person maintain the planned position while applying the cast; ensure that casting does not progressively force the hip farther into abduction.
Confirm reduction after application with intraoperative imaging and the planned post-casting imaging assessment.
(Tachdjian, Chapter 13.)
When to Abandon Closed Reduction
The hip cannot be reduced or requires ongoing lifting pressure to remain reduced.
The only stable position is extreme or threatens perfusion.
Arthrography demonstrates unacceptable interposition, excessive widening or poor seating.
The hip redislocates in the cast or at subsequent examination.
Failure to obtain a stable closed reduction is the principal indication for open reduction in the source. The choice of anterior or medial exposure then depends on age, anatomy, the need for capsulorrhaphy and the surgical plan (Tachdjian, Chapter 13).
Imaging and Follow-up
Limited CT, ultrasound or MRI can be used to confirm reduction in the cast. MRI can also assess femoral head perfusion when indicated. Persistent dislocation may be missed on a routine image if the unossified head is not clearly defined (Tachdjian, Chapter 13).
The authors commonly remove the first cast under anesthesia after 6 weeks, gently reassess stability without deliberately redislocating the hip, obtain imaging and apply another cast if reduction is maintained. Their regimen often includes three 6-week casts; other centers transition to abduction bracing after approximately 12 weeks. The duration must follow the child's reduction and development, and the source does not establish one mandatory immobilization schedule for every hip.
Complications and Pearls
Osteonecrosis: avoid forceful reduction and maximal abduction or excessive rotation.
Redislocation: confirm the head's position after casting and at cast changes rather than relying on the initial maneuver.
Residual dysplasia: successful reduction does not eliminate the need to monitor acetabular development.
False reassurance from a clunk: an apparent reduction at the acetabular entrance may still be nonconcentric.
Cast-related problems: positioning and fit need continued clinical supervision throughout immobilization.
(Tachdjian, Chapter 13.)
References
Herring JA, ed. Tachdjian's Pediatric Orthopaedics: From the Texas Scottish Rite Hospital for Children. 6th ed. Elsevier; 2022. Chapter 13, Developmental Dysplasia of the Hip, closed reduction, arthrography, safe zone and casting, pp. 446–451; Plate 13.1.