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Proximal femoral osteotomy correcting coxa valga and excessive anteversion to improve hip containment | advanced

Surgical Imaging

Varus derotation osteotomy with blade plate — Varus derotation osteotomy: an intertrochanteric medial closing wedge lowers the neck-shaft angle into varus and the proximal fragment is derotated, fixed with a fixed-angle blade plate.Credit: AI-generated medical image · OrthoVellum

Derotation reducing femoral anteversion — Derotation reduces excessive femoral anteversion, turning the femoral neck back into the acetabulum to improve containment and reduce the joint reaction force.Credit: AI-generated medical image · OrthoVellum

Pre and post VDRO hip radiographs — Pre- and post-operative hip radiographs: coxa valga with an uncovered subluxating head, corrected by varus derotation osteotomy and a blade plate to a concentric, well-covered hip.Credit: AI-generated medical image · OrthoVellum

Critical Danger Structures and Exam Traps

Over-Varus and Abductor Insufficiency

The trap: Maximising varus to gain coverage drops the neck-shaft angle below roughly 110 degrees, medialises the trochanter, slackens the abductors, and shortens the limb — producing a permanent Trendelenburg gait.

The fix: Plan correction to a neck-shaft angle of 110-120 degrees. Use the abduction view (Andren-von Rosen / abduction-internal-rotation radiograph) preoperatively to estimate the varus required for congruent reduction and stop there.

Profunda Femoris Perforators

Location: The perforating branches of the profunda femoris pierce the lateral intermuscular septum just behind the linea aspera, immediately posterior to the subtrochanteric/intertrochanteric osteotomy plane.

Risk: A posteriorly directed saw cut, an errant retractor behind the femur, or uncontrolled distal exposure can lacerate a perforator and cause brisk, difficult-to-control bleeding that retracts into the septum. Keep subperiosteal, protect the posterior cortex, and place a retractor flush on bone.

Blade/Screw Entering the Joint or Physis

Risk: The blade or fixed-angle screw aimed up the neck can breach the articular surface or cross the proximal femoral physis, causing chondrolysis, growth arrest, or a trochanteric overgrowth deformity.

Protection: Use a guidewire under image intensifier in two planes before committing the chisel/blade. Aim into the centre of the head, stopping short of subchondral bone, and stay distal to the physis in the skeletally immature hip.

Forgetting the Acetabular Side (DDH/CP)

Why different: In older DDH and neuromuscular subluxation the acetabulum is dysplastic and deficient. A femoral osteotomy alone leaves an uncovered head that will re-subluxate.

Implication: Combine VDRO with a pelvic osteotomy (Salter, Dega, Pemberton) and, when needed, open reduction plus soft-tissue release. Femur-only correction is appropriate mainly in Perthes containment and in the very young, remodelling hip.

Under-Correcting Anteversion

Why it matters: The femoral component of containment is rotational as much as angular. Leaving excessive anteversion (commonly greater than 50-60 degrees in CP and DDH) means the head still escapes anterolaterally despite a good neck-shaft angle.

The fix: Measure version preoperatively (CT or clinical Ryder test under image), and derotate to leave a physiological 10-15 degrees of anteversion. Mark rotation with longitudinal K-wires across the osteotomy before cutting.

Sciatic Nerve and Vascular Stretch (CP)

Why different: A long-standing high CP dislocation acutely reduced and derotated places the sciatic nerve and femoral vessels under tension; the limb is suddenly lengthened and re-orientated.

Implication: Add femoral shortening to decompress the joint and slacken the neurovascular structures. Avoid acute, large lengthening; monitor distal perfusion and nerve function postoperatively in the reduced, derotated limb.

Mnemonic

V.A.R.U.SVARUS — Goals and Pitfalls of the Femoral Osteotomy

Mnemonic

C.O.N.T.A.I.NCONTAIN — When to Add the Pelvic Side

Surgical Indications

Developmental Dysplasia of the Hip (DDH)

Residual dysplasia with femoral deformity — excessive anteversion and coxa valga preventing concentric, stable reduction
To aid concentric reduction — derotation and varus redirect the head deep into the acetabulum after open or closed reduction
Combined with pelvic osteotomy in the older child (typically over 18-24 months and especially over 4 years) where the acetabulum will not remodel

Perthes Disease (Containment)

Lateral pillar B and B/C border in children over 8 years (poorer prognosis groups benefit most from containment)
Femoral head at risk (Catterall/lateral pillar signs) in the fragmentation stage with a still-spherical, containable head
VDRO redirects the femoral head under the lateral acetabular margin during biological healing

Neuromuscular Hip (Cerebral Palsy)

Progressive hip subluxation — migration percentage greater than 40-50% (Reimers) despite postural management
Dislocation — painful or impeding seating/perineal care
Almost always combined with pelvic osteotomy (Dega/San Diego), adductor/psoas release, and frequently femoral shortening

Other

Residual SCFE deformity — proximal femoral realignment for residual varus/retroversion or impingement (a related, separate corrective osteotomy)
Coxa valga of other aetiology with documented uncovering

Contraindications

Absolute:

Active hip sepsis
A stiff, incongruent, non-containable (no longer spherical, "hinge abduction") Perthes hip — containment will worsen it

Relative:

Severe acetabular dysplasia where a femoral procedure alone is planned (add the pelvic side)
Skeletally mature patient with established arthritis (consider arthroplasty pathway)
Non-ambulant child with an asymptomatic, well-located hip (observe)

Biomechanical Rationale

VDRO works by redirection and unloading:

Coxa valga + anteversion rotates the load-bearing surface of the femoral head out of the acetabulum anterolaterally
Restoring a neck-shaft angle of 110-120 degrees and anteversion of 10-15 degrees points the head back into the socket
The medialised, varus proximal femur reduces the joint reaction force and improves the abductor working length when not overcorrected
In containment surgery (Perthes), the goal is to shelter the at-risk anterolateral head under the acetabular roof during healing

Evidence

Legg-Calve-Perthes disease. Part II: Prospective multicenter study of the effect of treatment on outcome

Level II

Herring JA, Kim HT, Browne R • J Bone Joint Surg Am

Clinical Implication: Defines the precise group that benefits from containment surgery (older than 8 years, lateral pillar B / B-C) and validates femoral VDRO as equivalent to pelvic osteotomy for containment — the central indication for VDRO in Perthes.

Verify on PubMed (PMID 15466720)

How does a femoral varus osteotomy alter the natural evolution of Perthes' disease?

Level III

Joseph B, Rao N, Mulpuri K, Varghese G, Nair S • J Pediatr Orthop B

Clinical Implication: Supports earlier-stage femoral VDRO in containable Perthes hips to preserve head sphericity, and underlines that timing (avascular / early fragmentation) influences the benefit obtained.

Verify on PubMed (PMID 15577301)

Combined femoral and pelvic osteotomies versus femoral osteotomy alone in the treatment of hip dysplasia in children with cerebral palsy

Level III

Al-Ghadir M, Masquijo JJ, Guerra LA, Willis B • J Pediatr Orthop

Clinical Implication: Justifies adding a pelvic (Dega/San Diego) osteotomy to femoral VDRO for the subluxated or dislocated CP hip — femur-only correction in established acetabular dysplasia carries a high revision rate.

Verify on PubMed (PMID 20104162)

Prevention of dislocation of the hip in children with cerebral palsy: 20-year results of a population-based prevention programme

Level II

Hagglund G, Alriksson-Schmidt A, Lauge-Pedersen H, Rodby-Bousquet E, Wagner P, Westbom L • Bone Joint J

Clinical Implication: Structured hip surveillance with the Reimers migration percentage enables earlier reconstructive VDRO and near-elimination of painful CP hip dislocation — the framework that drives the timing of this operation.

Verify on PubMed (PMID 25371472)

The stability of the hip in children: a radiological study of the results of muscle surgery in cerebral palsy

Guideline

Reimers J • Acta Orthop Scand Suppl

Clinical Implication: Establishes the migration percentage as the universal trigger metric for indicating and timing reconstructive VDRO in the cerebral palsy hip.

Verify on PubMed (PMID 6930145)

Indication-Specific Goals of VDRO

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"A 9-year-old boy with lateral pillar B Perthes disease in the fragmentation stage has a containable, spherical femoral head but increasing lateral extrusion. You are considering a femoral varus derotation osteotomy. How do you plan and perform it, and how do you avoid the common pitfalls?"

PRACTICAL APPROACH

My goal in this hip is containment: redirecting the at-risk anterolateral femoral head under the acetabular roof so it remodels in a contained, spherical position during healing. A 9-year-old with lateral pillar B disease is in the group most likely to benefit from surgical containment over non-operative treatment. **Confirm containability first**: I would obtain an abduction-internal-rotation view. If the head becomes congruent and better contained in abduction, it is containable and a varus osteotomy is appropriate. If there is hinge abduction (the head levering on the lateral acetabular margin and worsening congruency), containment is contraindicated and I would not proceed with a varus osteotomy. **Planning**: I measure the neck-shaft angle and anteversion. I plan a modest varus correction to a neck-shaft angle around 110-120 degrees — enough to contain, not maximal varus — and a small derotation if anteversion is excessive. I template the blade-plate angle to deliver that neck-shaft angle. **Technique**: Lateral approach to the proximal femur, strictly subperiosteal to protect the profunda perforators. I place a neck guidewire in two planes under image, then two rotation marker K-wires across the planned osteotomy. I seat the blade, make an intertrochanteric osteotomy with a laterally based closing wedge, derotate until the marker wires are parallel, close the varus, and fix the side plate to the shaft. I confirm a neck-shaft angle of 110-120 degrees and a contained head on imaging. **Avoiding pitfalls**: The key error is over-varus — dropping below 110 degrees gives a persistent Trendelenburg limp and shortening with limited benefit. I deliberately stop at my planned angle and rely on remodelling in this still-growing child. I would also plan for implant removal once united. **Aftercare**: Spica for around 6 weeks, then radiographic check, progressive weight-bearing after union, and abductor strengthening.

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"A 7-year-old non-ambulant child with spastic quadriplegic cerebral palsy has a right hip migration percentage of 60% with early pain on transfers. Adductor tenotomy two years ago has not prevented progression. How do you manage this hip?"

PRACTICAL APPROACH

This is a progressively subluxating neuromuscular hip in a non-ambulant child that has failed soft-tissue surgery — it needs bony reconstruction. My goal is a located, stable, painless, mobile hip for comfortable sitting and perineal care, not gait normalisation. **Assessment**: I confirm the migration percentage and trend on serial surveillance films, assess pain and seating/care difficulties, examine for fixed contractures (adductors, flexors, hamstrings), and image the acetabulum — in CP the deficiency is typically posterosuperior. I would get a CT or careful clinical assessment of femoral anteversion, which is usually markedly excessive. **Plan — combined reconstruction**: A migration percentage of 60% with pain in a child of this age is an indication for combined surgery, not femur-alone. I would perform: 1. **Soft-tissue release** — repeat adductor and psoas release to balance the deforming forces 2. **Femoral VDRO** — varus to a neck-shaft angle of 110-120 degrees, derotation to physiological anteversion, and importantly femoral shortening 3. **Pelvic osteotomy** — a Dega (San Diego) acetabuloplasty to reconstruct the deficient posterosuperior acetabulum 4. **Open reduction** if the head will not reduce concentrically **Why shortening matters**: Reducing a high, chronically subluxated hip acutely tensions the sciatic nerve and femoral vessels. Femoral shortening decompresses the joint, eases concentric reduction, protects the femoral head blood supply, and reduces neurovascular stretch. **Fixation and bone quality**: The bone is osteopenic, so I favour a locking proximal femoral plate. I confirm a concentric, contained reduction on imaging with no implant in the joint or physis. **Aftercare**: Spica or protected positioning, multimodal analgesia, careful neurovascular monitoring postoperatively, and continued hip surveillance of the contralateral hip. Plan implant removal once united.

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"You have completed a femoral varus derotation osteotomy and fixed it with a blade plate. Talk me through how you intraoperatively confirm you have achieved the correct varus AND derotation, and how you avoid over-correction."

PRACTICAL APPROACH

I treat varus and derotation as two separate, measured corrections, each with its own intraoperative check, rather than judging the final position by eye. **Derotation — the marker wire technique**: Before I make the osteotomy I place two longitudinal K-wires across the planned cut, one in the proximal fragment and one in the distal fragment, set apart by an angle equal to the anteversion I plan to remove (for example, if I want to remove 30 degrees of anteversion the wires diverge by 30 degrees). After the osteotomy I internally rotate the distal fragment until the two wires are parallel. When they are parallel, I have removed exactly my planned anteversion — this is reproducible and not a guess. **Varus — built into the implant**: I template and select the blade-plate angle so that, when the side plate sits flush on the shaft, the neck-shaft angle is my target of 110-120 degrees. The closing wedge I resect corresponds to the varus I am introducing. So the varus is largely pre-set by the device and the wedge; bringing the plate onto the shaft delivers it. **Imaging confirmation**: With the image intensifier I confirm the neck-shaft angle is 110-120 degrees on the AP view and that anteversion is physiological. I check the blade/screw is in the centre of the head, short of the joint, and not across the physis. **Avoiding over-correction**: The commonest error is over-varus chasing coverage. I plan my correction from the preoperative abduction view and the anteversion measurement and then stop at my plan — I do not add varus to 'gain a bit more cover'. In a young child I deliberately undercorrect slightly because remodelling will do the rest, whereas in an adolescent I correct precisely because there is no remodelling reserve. If I have also shortened the femur, I am especially conservative with varus to protect abductor function and limb length.