varus derotation osteotomy
varus derotation osteotomy hip pediatric cerebral palsy
This series of three anteroposterior radiographs documents the surgical management and progression of hip subluxation in an 8-year-old female patient with cerebral palsy (GMFCS level V). Image A (preoperative) demonstrates severe lateral and superior subluxation of the left femoral head relative to the dysplastic acetabulum, characterized by a Migration Percentage (MP) of 74%. Image B, captured 6 weeks postoperatively, shows significant improvement in femoral head coverage and joint congruency following a combined femoral varus derotation osteotomy (VDRO) and Dega-type pelvic osteotomy. Orthopedic hardware, specifically a locked compression plate with multiple screws, is visible providing internal fixation on the proximal femur. Image C, taken 2.9 years postoperatively, illustrates a clinical relapse of the hip subluxation (MP 51%). The femoral head has migrated laterally despite the continued presence of the surgical hardware, indicating loss of correction over time. This comparison highlights the challenges of maintaining hip stability in non-ambulatory pediatric patients with neuromuscular conditions.
This composite diagnostic image features two anteroposterior (AP) pelvic radiographs of a pediatric patient, illustrating preoperative and postoperative states of neuromuscular hip dysplasia secondary to cerebral palsy. Image (a) demonstrates a complete dislocation of the left hip joint. Key radiographic findings include a shallow, dysplastic acetabulum with inadequate superior coverage and a high-riding femoral head. The proximal femur shows a significant valgus deformity (coxa valga). Image (b) displays the results of surgical reconstruction. The left hip is now reduced, with the femoral head centered within the acetabulum. Surgical hardware, including an orthopedic plate and screws, is visible on the proximal femur, indicating a varus derotation osteotomy (VDRO) used to correct the femoral alignment. Structural changes in the ilium above the acetabulum are consistent with a pelvic osteotomy (Dega type) to improve acetabular depth and coverage. These images serve as an educational example of complex hip reconstruction in pediatric orthopedic surgery.
This sequence of three anteroposterior (AP) pelvic radiographs illustrates the longitudinal management of hip dysplasia in a pediatric patient with Gross Motor Function Classification System (GMFCS) level V. Image A (Preoperative): Shows severe bilateral hip subluxation, more pronounced on the right, where the femoral head is laterally displaced with a high migration percentage (MP 67%), indicating significant lack of acetabular coverage. Image B (1-Day Postoperative): Demonstrates immediate results following a combined right-sided femoral varus derotation shortening osteotomy (VDSO) and Dega pelvic osteotomy. A pediatric locked compression plate (LCP) and multiple screws fix the proximal femur. The pelvic osteotomy site is visible as an open wedge containing a bone graft, effectively increasing femoral head coverage. Image C (7.4-Year Follow-up): Shows the long-term outcomes at age 14.4. There is successful remodeling and consolidation of the pelvic osteotomy site. The right hip maintains improved stability (MP 19%) with the orthopedic hardware still in situ. The left hip shows complete coverage (MP 0%). This sequence highlights the efficacy of combined bony procedures for hip stabilization in non-ambulatory cerebral palsy patients.
A series of six anteroposterior (AP) pelvic radiographs demonstrating a comparison of pre-operative and post-operative status following a Varus Derotation Osteotomy (VDRO) for neuromuscular hip dysplasia. Images A, B, and C show the pre-operative baseline where bilateral coxa valga and subluxation of the femoral heads are present; quantitative measurements include the migration percentage (MP) in A, the acetabular index (AI) in B, and the anatomical medial proximal femoral angle (aMPFA) in C. Images D, E, and F show the post-operative outcomes using the same measurement techniques. Visible surgical changes include bilateral proximal femoral plates and screws used for internal fixation. Post-operative views demonstrate improved coverage of the femoral heads within the acetabula, correction of the femoral neck-shaft angle to a more varus orientation, and stabilization of the hip joint. The content illustrates the radiographic assessment of hip dysplasia progression and surgical correction in the context of cerebral palsy management.
varus derotation osteotomy hip outcomes
femoral varus osteotomy hip dysplasia cerebral palsy
Varus Derotation Osteotomy (VDRO)
Definition and Concept
- Reduces the neck-shaft (NSA/valgus) angle - by removing a laterally-based wedge, converting coxa valga to a more varus orientation
- Derotates the femur - by externally rotating the distal fragment to reduce excessive femoral anteversion
Pathological Basis
| Deformity | Normal | Pathological |
|---|---|---|
| Neck-shaft angle (NSA) | ~130° (child) | Coxa valga: >145° |
| Femoral anteversion | 10-15° (adult) | Increased anteversion: >40° |
Indications
1. Cerebral Palsy (CP) - Hip Subluxation/Dislocation (PRIMARY indication)
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Pathology: Spastic muscle imbalance (adductors/flexors overpower abductors/extensors) combined with bony deformity (coxa valga + increased anteversion). GMFCS V patients have nearly 90% risk of hip displacement.
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Surveillance: Migration Percentage (MP) is the key radiographic measure (Reimers index)
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Treatment algorithm by MP:
- MP <25%: observation, physiotherapy, abduction splinting
- MP 25-40%: soft-tissue releases (adductor ± psoas) ± proximal femoral guided growth
- MP >40-60%: VDRO with or without pelvic osteotomy + soft-tissue lengthening
- MP >70%, dislocation: VDRO + open reduction + acetabular osteotomy (Dega/Salter/Pemberton)
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Surgical target: Reduce NSA to approximately 120° in ambulatory patients; even less in non-ambulatory patients.
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Results: Varus derotational osteotomy was found effective in preventing redislocation and further surgery in 84% of cases. Good results in 95% at 7-year follow-up when combined with soft-tissue lengthening, open reduction (if MP >70%), and pericapsular acetabuloplasty.
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Risk factors for failure: Age <6 years at surgery, preoperative MP >70%, acetabular index >25°
2. Developmental Dysplasia of the Hip (DDH)
- Used as a concomitant procedure during open reduction when instability persists
- Indicated when femoral coxa valga or anteversion is the primary cause of instability after acetabular correction
- In children >12 months, can be done alongside innominate/acetabular osteotomy
- In children <12 months, acetabular remodeling potential may be sufficient; VDRO may not be necessary
3. Legg-Calvé-Perthes Disease (LCPD)
- Used as a containment procedure for the fragmented femoral head
- Indicated in children >6 years with Herring lateral pillar group B/C disease
- The femoral varus positions the head deeper within the acetabulum, improving containment during the revascularization phase
- Comparative studies show it performs similarly to abduction-abduction bracing in achieving containment
4. Paralytic Hip Dislocation (Poliomyelitis)
- When severe coxa valga or anteversion requires >20-30 degrees of abduction for stability, VDRO with internal fixation is performed (often in conjunction with iliopsoas transfer)
5. Neuromuscular Conditions (Spina bifida, myelomeningocele)
- Open reduction combined with femoral shortening, VDRO, and acetabular reconstruction for paralytic dislocations
6. Supramalleolar Variant
- A supramalleolar varus derotation osteotomy of the distal tibia is a separate procedure used for severe ankle valgus deformity in adolescents (different anatomy, same principle)
Surgical Technique - Proximal Femoral VDRO
Approach
- Lateral or anterolateral approach to proximal femur
- Level: typically subtrochanteric or intertrochanteric region
Key Steps
- Planning: Preoperative templating to determine the wedge angle (for varus correction) and rotation (for derotation). Anteversion measured clinically or by CT.
- Osteotomy: A closing laterally-based wedge osteotomy reduces the NSA. Simultaneous external rotation of the distal fragment corrects anteversion.
- Shortening: If combined with open reduction, 1-2 cm of shortening facilitates reduction without undue pressure on the femoral head.
- Fixation: Blade plate, angled barrel plate, or pediatric locking compression plate (LCP) with multiple screws for internal fixation.
- Cast: Hip spica cast (45° flexion, 30° abduction) or abduction pillow for 4-6 weeks postoperatively.
Combined Procedures
| Procedure | Purpose |
|---|---|
| Adductor ± psoas release | Relieve deforming muscle forces |
| Open reduction (capsulorraphy) | Required if MP >70% |
| Dega osteotomy | Correct posterosuperior acetabular deficiency (most common pattern in CP) |
| Salter / Pemberton osteotomy | For anterior/lateral deficiency (must match to deficiency site) |
| Femoral shortening | Reduces compression on femoral head after reduction |
Caution: Careful matching of acetabular osteotomy to the area of deficiency is essential. A Salter osteotomy redirects the acetabulum posterolaterally; if done in a patient with posterior deficiency, it can worsen femoral head uncovering. CT morphometry best identifies the location of acetabular deficiency.
Complications
- Avascular necrosis (AVN) of the femoral head - risk increased by excessive shortening, over-correction, and vascular injury (a 2025 study specifically examined risk factors for AVN post-VDRO in CP; PMID: 40654122)
- Resubluxation/Redislocation - especially in GMFCS IV-V, with MP increasing 2-3.5%/year; long-term surveillance mandatory
- Leg length discrepancy - if unilateral shortening is not accounted for
- Implant failure / hardware prominence - common in young, thin children
- Medical complications (wound infection ~3-5%, pulmonary complications) - these constitute 83% of complications in one large series
- Trochanteric overgrowth - if the greater trochanter is not advanced after significant shortening
Radiographic Assessment
| Measurement | Purpose | Threshold for VDRO |
|---|---|---|
| Migration Percentage (MP) | Femoral head uncovering | >40-60% |
| Neck-Shaft Angle (NSA) | Coxa valga | >145° in older children |
| Acetabular Index (AI) | Acetabular dysplasia | >25° may need pelvic osteotomy |
| Center-Edge Angle (CEA) | Lateral head coverage | <20° = deficient |
| Femoral anteversion | Rotation deformity | >40° usually |
Postoperative Care
- Hip spica cast or abduction pillow: 4-6 weeks
- Physical therapy (ROM + progressive weight-bearing) after cast removal and radiographic healing
- Surveillance radiographs every 6 months until hip stability is confirmed
Radiographic Illustrations
Key Summary Points
- VDRO = proximal femoral osteotomy correcting valgus + anteversion simultaneously
- Main indication: CP hip subluxation/dislocation (MP >40-60%)
- Surgical goal: NSA to ~120° (ambulatory) or lower (non-ambulatory)
- Almost always combined with soft-tissue releases + pelvic osteotomy in CP
- Risk of failure higher with: age <6 years, MP >70%, uncorrected acetabular dysplasia
- Dega osteotomy is the preferred pelvic partner in CP due to typical posterosuperior acetabular deficiency
- Recent alternative for younger children: proximal femoral medial hemiepiphysiodesis (guided growth) to gradually correct coxa valga before formal VDRO is needed
video
varus derotation osteotomy VDRO surgical technique video YouTube
- Video 1 covers the concept and indication in CP (good for understanding the "why")
- Video 2 is the most relevant for surgical technique - demonstrates the actual osteotomy and LCP plate fixation step by step under image intensification
- Video 3 shows intraoperative details including screw placement and derotation correction