Surgical technique for resection of partial physeal bars (bony bridges) across injured growth plates to halt progressive angular deformity or limb-length discrepancy in skeletally immature children — pre-operative mapping, approach, interposition, and outcomes
High-yield overview
Excision of a partial physeal bony bridge with interposition graft to restore growth and correct progressive deformity | advanced
Surgical Imaging
Critical Decision Points and Exam Traps
Bar Size — The 50 Percent Rule
The threshold: Resection is generally worthwhile when the bar occupies less than roughly 50 percent of the physis cross-sectional area on CT arthrography or MRI.
Why it matters: Larger bars have significantly higher recurrence rates and less remaining open physis to resume growth after excision. A bar exceeding 50 percent of the physis often means the remaining healthy physis cannot compensate, and completion epiphysiodesis is the more appropriate option.
Growth Remaining — The 2-Year / 2-cm Rule
The threshold: The child should have at least 2 years or 2 cm of growth remaining at the affected physis for resection to offer meaningful benefit.
Assessment: Use bone age (Greulich-Pyle hand-wrist, or TW2/TW3), skeletal maturity scores (Risser sign, Oxford method), and growth-remaining tables (Anderson-Green, or Moseley straight-line graph). A child near skeletal maturity gains nothing from bar resection — the physis will close before corrective growth can occur.
The trap: Using chronological age alone rather than bone age. A 12-year-old girl may be skeletally mature, while a 14-year-old boy may still have significant growth remaining.
Central vs Peripheral Bar — Approach and Prognosis
Peripheral bar (outer third of physis): approached through a metaphyseal cortical window adjacent to the bar. The surgeon works in from the side without violating the epiphysis or the remaining healthy physis. Lower recurrence, better outcomes.
Central bar: requires drilling through the epiphysis to reach the bar, potentially damaging articular cartilage and passing through healthy physis. Higher recurrence rates, more technically demanding, and reserved for children with sufficient growth to justify the attempt.
Interposition Material Selection
Autologous fat graft (Langenskiold, 1967): the most widely used. Harvested from buttock or abdomen through a separate small incision. Free fat graft can partially resorb over time, losing barrier function — a theoretical mechanism for late recurrence.
Cranioplast (hydroxyapatite cement): radiopaque, visible on follow-up imaging, permanent, and does not resorb. Allows radiographic confirmation of interposition position and volume on serial radiographs.
PMMA bone cement: also radiopaque and permanent. Prepared and placed as a mouldable dough that hardens in the cavity.
Fat graft remains the most commonly used and has the longest track record, but cranioplast offers the advantage of radiographic verification of the interposition.
Bar Recurrence — The Most Common Failure
Incidence: Reported recurrence rates range from approximately 10 to 30 percent across series, with central bars and smaller interposition volumes carrying higher risk.
Mechanism: Incomplete excision of the bar, fat graft resorption, or new bone formation across the resection cavity. Re-formation of the bridge arrests growth again, and the deformity or limb-length discrepancy resumes progression.
Prevention: Meticulous excision back to healthy physis confirmed on intraoperative fluoroscopy and arthrography; adequate interposition material filling the entire cavity; avoidance of bleeding into the cavity; postoperative CT or MRI at 6 to 12 months to check for re-formation.
Completion Epiphysiodesis as Alternative
When resection is not viable: If the bar exceeds 50 percent of the physis, or growth remaining is less than 2 years or 2 cm, resection is unlikely to succeed or benefit.
The alternative: Completion (surgical) epiphysiodesis of the entire remaining physis on the affected side, combined with contralateral epiphysiodesis (to stop the opposing growth and prevent worsening LLD) or with planned limb lengthening if the discrepancy is unacceptable.
Key difference: Completion epiphysiodesis accepts the current deformity and LLD as final — no further correction through growth is possible. It is a simpler procedure with lower recurrence risk but no potential for spontaneous improvement.
Mnemonic
B.R.I.D.G.EB.R.I.D.G.E. — Decision Framework for Physeal Bar Resection
Mnemonic
S.P.A.C.E.RS.P.A.C.E.R. — Operative Steps for Physeal Bar Resection
Mnemonic
R.E.C.U.R.RR.E.C.U.R.R. — Reasons Bar Recurs After Resection
Surgical Indications
Absolute Indications
Partial physeal bar occupying less than roughly 50 percent of the physis cross-section, confirmed on CT arthrography or MRI
Progressive angular deformity or limb-length discrepancy attributable to the partial physeal arrest
Sufficient growth remaining: at least 2 years or 2 cm of growth potential at the affected physis (confirmed by bone age assessment)
Skeletally immature patient: open physis on the affected and contralateral side
Relative Indications
Bar between 30 and 50 percent of physis — proceed if sufficient growth remains and the bar is surgically accessible (peripheral location favoured)
Multi-level physeal arrest (rare) — staged resection at different sites may be considered
Patient and family preference for growth-reserving surgery over completion epiphysiodesis
Contraindications
Absolute:
Bar occupying greater than 50 percent of the physis cross-section (too large, high recurrence, insufficient healthy physis remaining)
Insufficient growth remaining (less than 2 years or less than 2 cm at affected physis)
Near-complete or complete skeletal maturity (physis closed or closing)
Active infection at the operative site
Relative:
Central bar in a joint with limited surgical access (e.g. central distal femoral bar with high risk to articular cartilage)
Previous failed bar resection at the same site (recurrence)
Significant medical comorbidities or poor bone quality that compromise healing
Complex multiplanar deformity better addressed by acute osteotomy and external fixation
Decision: Resection vs Completion Epiphysiodesis
The central surgical decision in partial physeal arrest is whether to attempt growth-restoring bar resection or to accept the current state with completion epiphysiodesis (arresting the entire remaining physis).
Resection is chosen when the bar is small enough, growth remaining is sufficient, and the surgeon expects meaningful spontaneous correction of angular deformity or limb-length discrepancy through resumed growth.
Completion epiphysiodesis is chosen when the bar is too large, growth remaining is too little, or the deformity is severe enough that spontaneous growth correction will be insufficient even if the bar is excised successfully. In this case, the entire physis is surgically arrested (physeal scraping, drilling, or cannulated screw insertion), and contralateral epiphysiodesis is performed at an appropriately timed stage to manage the limb-length discrepancy. Limb lengthening may be added if the predicted final LLD is unacceptable.
Physeal Bar Resection vs Completion Epiphysiodesis — Decision Comparison
Evidence Base
Original Technique
Langenskiold (1967) described the technique of physeal bar resection with autologous fat graft interposition in the distal femur and proximal tibia. The approach passes through a metaphyseal cortical window adjacent to the bar, the bony bridge is excised under direct vision, and the defect is filled with free fat harvested from the buttock or abdomen. This remains the foundational technique.
Bar Classification and Location
Peterson (1984) classified physeal bars by type (peripheral, central, linear, and combined) and correlated bar location and size with outcome. Peripheral and smaller bars had better correction and lower recurrence than central and larger bars. This classification guides surgical planning and prognostication.
Imaging for Mapping
CT arthrography (contrast injected into the joint or metaphyseal area before scanning) provides high-resolution cross-sectional mapping of the bar size, shape, and relationship to the remaining physis. It has historically been the gold standard for surgical planning.
MRI with cartilage-sensitive sequences (T2-weighted, fat-suppressed, or SPGR) has become increasingly used as the primary mapping modality. MRI avoids ionising radiation, visualises the cartilaginous physis and the osseous bar on the same study, and can detect early partial arrest before the bar is visible on plain radiographs.
Outcomes
Published series report complete resolution or significant improvement in progressive deformity in approximately 50 to 80 percent of patients with peripheral bars, and lower rates (30 to 60 percent) with central bars. Recurrence rates range from approximately 10 to 30 percent and are highest with central bars and with fat graft interposition that resorbs over time. Outcomes are best in younger children with smaller peripheral bars and longer growth remaining.
The Physis (Growth Plate) — Relevant Anatomy
Structure and Zones
The physis is a cartilaginous disc between the epiphysis and metaphysis organised into zones (from epiphyseal to metaphyseal side):
Resting zone (germinal): reserve chondrocytes at the epiphyseal border
Hypertrophic zone: chondrocytes enlarge; this is the weakest zone and the site of Salter-Harris fracture separation
Zone of provisional calcification: chondrocyte columns undergo mineralisation before replacement by metaphyseal bone
The physis is tethered circumferentially by the perichondral ring (ring of La Croix) and the periosteum, which provide mechanical stability and are important structures to protect during surgical approaches.
Blood Supply
Epiphyseal side: supplied by epiphyseal vessels entering through the epiphysis (disruption by infection or fracture can affect the germinal zone)
Metaphyseal side: supplied by metaphyseal nutrient vessels (interruption does not typically affect physeal growth)
Perichondral ring: receives vessels from the periosteum — surgical disruption during approach can damage this stabilising structure
Closure Pattern
Physes close centripetally (periphery closes before centre) and at different rates by bone and sex:
Distal femur: contributes approximately 9 mm/year of lower limb growth; closes around age 14 in girls and 16 in boys
Proximal tibia: approximately 6 mm/year; closes around same ages as distal femur
Distal tibia: approximately 5 mm/year; closes slightly earlier than the proximal sites
This is clinically important because a small bar at the distal femur (the single largest contributor to lower limb growth) can produce rapid and severe progressive deformity or LLD.
Physeal Bar — Pathophysiology
Formation
A physeal bar forms when a bony bridge develops across part of the growth plate after injury to the physis. Common causes include:
Salter-Harris type III-V fractures (especially SH IV and V, which directly damage the physeal cartilage)
Periarticular infections (osteomyelitis adjacent to the physis)
Iatrogenic injury (surgical approach or hardware placement crossing the physis)
Thermal or radiation injury to the growth plate
Tumour or tumour resection involving the physis
Ischaemic injury (e.g. compartment syndrome, vascular insult to the epiphysis)
Why Deformity Progresses
The arrested portion of the physis stops producing longitudinal growth. The remaining open physis continues to grow, creating asymmetric growth that manifests as:
Angular deformity: progressive valgus or varus at the affected physis (e.g. distal femoral lateral bar causing progressive valgus)
Limb-length discrepancy: shortening on the affected side if the entire medial-lateral span is partially tethered
Combined: both angular deformity and LLD, depending on bar location and size
The rate of deformity progression depends on the remaining growth velocity at the affected physis, the proportion of the physis that is arrested, and the distance of the bar from the mechanical axis.
Bar Location — Surgical Approach Implications
Peterson Classification
Peripheral
Description
Bar at outer margin of physis
Approach Implications
Metaphyseal cortical window adjacent to bar; no violation of epiphysis
Prognosis
Best outcomes; lowest recurrence
Central
Description
Bar in central region of physis
Approach Implications
Requires drilling through epiphysis; risk to articular cartilage
Prognosis
Higher recurrence; technically demanding
Linear
Description
Bar extends partially across physis in a line
Approach Implications
Approach from one end through metaphysis
Prognosis
Intermediate; depends on length
Combined
Description
Large bar involving peripheral and central zones
Approach Implications
May require combined approach or staged resection
Prognosis
Poorer prognosis; consider epiphysiodesis
Type
Description
Approach Implications
Prognosis
Peripheral
Bar at outer margin of physis
Metaphyseal cortical window adjacent to bar; no violation of epiphysis
Best outcomes; lowest recurrence
Central
Bar in central region of physis
Requires drilling through epiphysis; risk to articular cartilage
Higher recurrence; technically demanding
Linear
Bar extends partially across physis in a line
Approach from one end through metaphysis
Intermediate; depends on length
Combined
Large bar involving peripheral and central zones
May require combined approach or staged resection
Poorer prognosis; consider epiphysiodesis
Surgical Access by Site
Distal femur: most common site; approach from medial or lateral metaphysis depending on bar location; image intensifier essential; protect popliteal neurovascular structures posteriorly
Proximal tibia: anteromedial approach common; protect tibial aponeurosis, pes anserinus, and the saphenous vein/nerve; posterior tibial neurovascular bundle at risk with deep posterior dissection
Distal tibia: medial approach standard; protect the tibialis posterior tendon and the flexor hallucis longus; posteromedial neurovascular bundle must be identified and safeguarded
Pre-operative Planning
Imaging
CT arthrography: high-resolution cross-sectional images of the bar with contrast delineating the remaining open physis. Provides precise mapping of bar size, shape, and surgical access trajectory.
MRI with cartilage-sensitive sequences: maps the bar without radiation; preferred when available; T2-weighted fat-suppressed or 3D SPGR sequences best visualise the osseous bar against the cartilaginous physis.
Plain radiographs: AP and lateral of the affected limb; scanogram for limb-length measurement; assess skeletal maturity (Tanner-Whitehouse or Greulich-Pyle from hand-wrist radiograph).
Bone age: essential for growth prediction. Compare with chronological age — significant discrepancy changes growth predictions.
Growth Prediction
Use a straight-line graph (Moseley method) or growth-remaining tables to estimate the deformity and LLD at skeletal maturity. If the predicted LLD exceeds acceptable limits (commonly cited as 2 cm for the lower limb) and cannot be corrected by growth resumption alone, plan for contralateral epiphysiodesis or limb lengthening.
Positioning and Preparation
Patient position: Supine on a radiolucent table. A sandbag or bump under the ipsilateral hip may improve access for medial distal femoral or proximal tibial approaches. Ensure the image intensifier can obtain true AP and lateral views without moving the limb.
Tourniquet: thigh tourniquet for distal femoral and proximal tibial procedures; calf tourniquet or no tourniquet for distal tibial procedures. Ensure limb exsanguination before inflation.
Anaesthesia: General anaesthesia. Peripheral nerve block (femoral or sciatic, depending on site) for post-operative analgesia. Ensure adequate muscle relaxation for intraoperative manipulation and image intensifier positioning.
Fluoroscopy: Image intensifier positioned to obtain true AP and lateral views of the affected physis before draping. Confirm the physis is open and the bar is visible. Mark the surgical landmarks with a radioopaque marker.
Consent: Specifically counsel regarding risk of bar recurrence (10-30 percent), incomplete correction, progressive deformity requiring further surgery, infection, nerve or vessel injury (particularly around the knee and ankle), and the possibility that completion epiphysiodesis may ultimately be required if resection fails.
Fat graft harvest site: Prepare and drape the ipsilateral buttock or lower abdomen as a separate field for fat graft harvest.
Operative Technique — Peripheral Bar (Metaphyseal Approach)
Step 1: Approach and Cortical Window
Plan the approach based on the CT/MRI map: the metaphyseal cortical window should be positioned directly adjacent to the bar, avoiding the epiphyseal plate and joint surface.
For a distal femoral lateral bar: lateral parapatellar approach or direct lateral metaphyseal incision, elevating the vastus lateralis to expose the lateral femoral metaphysis. Protect the lateral superior genicular vessels.
For a proximal tibial medial bar: anteromedial incision over the proximal tibial metaphysis, distal to the physis. Protect the pes anserinus tendons and the saphenous nerve running along the sartorius.
For a distal tibial medial bar: medial incision over the distal tibial metaphysis, elevating the flexor digitorum longus sheath. Identify and protect the tibialis posterior tendon and the posteromedial neurovascular bundle.
Clinical Pearl
Technical Tip: "I study the CT arthrography map on the day of surgery and plan my cortical window position so that my line of approach passes directly through the bar. I draw the trajectory on the skin with a radioopaque marker and confirm it with the image intensifier before incising. The window must be large enough to allow adequate visualisation and instrumentation but not so large as to compromise the metaphyseal cortex."
Step 2: Create the Metaphyseal Window
Using a burr or osteotome, create a cortical window in the metaphysis directly adjacent to the bar. The window should be approximately 1.5 to 2 cm in diameter (or larger for extensive bars). Flush the bone fragments away with saline irrigation.
Under fluoroscopic guidance, advance the burr or curette toward the bar tissue. The bar appears as dense, sclerotic white bone contrasting with the adjacent normal cancellous metaphyseal bone and the cartilaginous physis.
Dangers at this step
Drilling too deep past the bar into the epiphysis or joint surface — use intermittent fluoroscopy to confirm depth
Creating the window too close to the physis and violating the remaining healthy growth plate — stay in the metaphysis until the bar is reached
Damaging neurovascular structures posteriorly at the distal femur (popliteal bundle) or distal tibia (posteromedial neurovascular bundle) — stay anterior and subperiosteal
Step 3: Excise the Physeal Bar
Under direct vision and fluoroscopic guidance, excise the bar using small curettes (2 mm to 4 mm), a burr, or a high-speed diamond burr. Excise all visible bony bridge tissue, working from the metaphyseal side toward the physis.
The endpoint is reached when:
All dense, white sclerotic bone has been removed from the bar area
The underlying cartilaginous physis is visible and appears healthy (glistening, smooth)
The curette passes freely from the metaphyseal cavity into the epiphyseal side without encountering residual bone
Clinical Pearl
Technical Tip: "I use a combination of small curettes and a high-speed burr, checking frequently with the image intensifier. I excise layer by layer, removing the dense bar tissue while protecting the adjacent healthy physis. Once I think the bar is clear, I perform an intraoperative arthrogram — injecting contrast through the cavity and checking on fluoroscopy that dye passes freely across the physis into the epiphysis and metaphysis. If there is any blockage, I go back and remove more tissue until the dye flows unimpeded."
Dangers at this step
Incomplete excision — the most common cause of recurrence; curette layer by layer, not aggressively
Extending the curette beyond the bar into healthy physis — damages remaining growth cartilage and may create a new bar
Pushing curette or burr through the epiphysis into the joint — catastrophic articular cartilage injury; monitor depth with fluoroscopy
Bleeding into the cavity obscuring the view — pack temporarily, control with cautery, then resume excision
Step 4: Verify Completeness of Excision
Perform an intraoperative arthrogram: inject radiocontrast dye through the resection cavity into the physis. Under fluoroscopic AP and lateral views, confirm that dye passes freely across the previously tethered area from epiphysis to metaphysis.
If the dye flow is blocked or impeded, residual bar tissue remains. Return to curettage until the dye flows freely.
An alternative is saline injection: inject saline and observe free flow from the cavity. Arthrogram is preferred for radiographic confirmation.
Step 5: Interposition Material
Fill the resection cavity with the chosen interposition material:
Harvest approximately 5 to 10 mL of subcutaneous fat from the buttock or abdomen through a small separate incision
Mince the fat into small fragments and pack the resection cavity firmly, ensuring no dead space remains
The fat should fill the cavity completely and be in contact with the walls
Cranioplast (hydroxyapatite cement):
Mix the cranioplast powder with the recommended liquid to form a workable paste
Pack the paste into the resection cavity, moulding it to fill the space
Allow it to harden in situ (typically 5 to 10 minutes)
Confirm position and fill on fluoroscopy — cranioplast is radiopaque
PMMA bone cement:
Prepare bone cement on the back table, allow to reach dough stage
Pack into the cavity and allow to harden
Confirm radiographic position
Clinical Pearl
Technical Tip: "I prefer autologous fat graft as my primary interposition because it has the longest track record and avoids introducing foreign material. However, in central bar resections or revision cases where recurrence risk is higher, I add a cranioplast cap on top of the fat — the cranioplast is radiopaque and lets me verify on post-operative imaging that the interposition remains in position and has not resorbed."
Step 6: Close Cortical Window and Wound
Replace the cortical bone window if it was removed as a single fragment (fix with a small screw or leave it free if sufficiently stable). Irrigate the wound thoroughly. Close the metaphyseal periosteum. Close the fascial layer, subcutaneous tissue, and skin in layers.
Apply a well-padded above-knee or below-knee plaster back-slab (depending on site) for initial immobilisation.
Operative Technique — Central Bar (Epiphyseal Approach)
Approach
Central bars require a different surgical approach because they are not accessible from the metaphyseal side without traversing the entire physis.
The approach is through the epiphysis: a drill trajectory is planned on the pre-operative CT/MRI map, entering the epiphysis from a point on the articular surface (or just adjacent to it) and aiming directly at the central bar. The entry point must be chosen to minimise articular cartilage damage.
This approach is more technically demanding because:
The drill passes through articular or perichondral cartilage to reach the bar
The remaining healthy physis surrounds the bar and must be protected
The resection cavity is deeper and more confined
Recurrence rates are higher than for peripheral bar resection
Technique
Plan the drill trajectory on CT/MRI; mark entry point on the epiphysis under fluoroscopy
Create a small drill hole through the epiphyseal cartilage (2 mm to 4 mm cannulated drill)
Advance a guidewire through the drill hole into the bar under fluoroscopic guidance
Ream over the guidewire to create an access channel to the bar
Excise the bar using curettes and burrs passed through the access channel
Verify completeness with intraoperative arthrogram (dye flowing freely across the physis)
Fill the cavity with interposition material (fat, cranioplast, or PMMA)
Close the epiphyseal entry point; repair the articular cartilage defect if feasible
Dangers at this step
Articular cartilage damage at the drill entry point — minimise the defect size; entry through non-weight-bearing area when possible
Iatrogenic damage to the remaining healthy physis during access — the central bar is surrounded by functional growth cartilage; stay within the bar margins
Incomplete excision — central bars are harder to visualise and assess; intraoperative arthrogram is essential
Concurrent Corrective Osteotomy
When angular deformity is already established at presentation, bar resection alone resumes growth but cannot correct the existing deformity in a reasonable time. A concurrent corrective osteotomy is frequently required.
Timing options:
Simultaneous: osteotomy performed at the same sitting, through the same approach or a separate incision. Advantage: one anaesthetic, one recovery. Disadvantage: longer surgery, more blood loss.
Staged: bar resection first, then osteotomy 6 to 12 weeks later. Advantage: allows initial healing of the resection site. Disadvantage: two operations, two recoveries.
Osteotomy type: closing-wedge, opening-wedge, or dome (convex) osteotomy depending on the site, deformity, and surgical plan. Fix with plate-and-screws, K-wires, or external fixation depending on the site and bone quality.
Immobilisation: Above-knee or below-knee plaster back-slab (or cast depending on site and concurrent osteotomy) for 4 to 6 weeks. If concurrent osteotomy was performed, immobilisation follows the osteotomy protocol.
Elevation: Limb elevated for the first 48 hours to reduce swelling.
Analgesia: Paracetamol and NSAIDs; opioid PRN for the first 48 to 72 hours; peripheral nerve block for extended analgesia.
Wound care: Check wound at 7 to 10 days. Suture removal at 10 to 14 days.
Thromboprophylaxis: Not routinely required for paediatric lower limb surgery in mobile patients; consider mechanical prophylaxis in adolescents with additional risk factors.
Rehabilitation Phase (Weeks 6-12)
Mobilisation: Begin protected weight-bearing in a cast or brace after 4 to 6 weeks; progress to full weight-bearing as tolerated.
Range of motion: Gentle active and active-assisted ROM exercises of the affected joint; avoid forced manipulation.
Physiotherapy: Supervised programme for gait re-education, ROM, and quadriceps/hams reactivation (for distal femur and proximal tibia sites).
Long-term Follow-up
Serial radiographs: Every 3 to 6 months for at least 2 years, then annually until skeletal maturity.
Deformity monitoring: Measure the mechanical axis deviation and LLD on each visit. Plot on a growth prediction chart (Moseley straight-line graph) to predict outcome at maturity.
Imaging for bar recurrence: MRI or CT arthrography at 6 to 12 months post-operatively to check for bar re-formation and interposition position. Repeat if clinical or radiographic signs suggest recurrence (worsening deformity, new tether on plain radiographs).
Growth monitoring: Monitor the physis for resumption of growth in the previously tethered zone. Compare growth velocity on the operated side with the contralateral side.
Contrast: When to Choose Completion Epiphysiodesis Instead
Bar resection is the growth-preserving option, but it is not always appropriate or successful. Completion epiphysiodesis should be considered when:
The bar exceeds 50 percent of the physis — resection is unlikely to restore sufficient growth
Growth remaining is less than 2 years or 2 cm — the physis will close before meaningful correction occurs
Bar recurrence after previous resection — a second attempt has diminishing success; completion epiphysiodesis is the pragmatic choice
Severe multiplanar deformity that cannot be corrected by growth alone, even with successful bar resection
Completion epiphysiodesis technique: Surgical arrest of the entire remaining physis by drilling or curettage (Phemister technique) or percutaneous cannulated screw insertion. Combined with contralateral epiphysiodesis (timed using Moseley charts to equalise limb lengths at maturity) or with limb lengthening if the predicted LLD is unacceptable.
Key teaching point: Completion epiphysiodesis trades the possibility of further growth correction for certainty — the deformity and LLD will not worsen, but they will not improve spontaneously. For the exam, be clear about which clinical scenarios favour resection versus completion epiphysiodesis.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
Viva scenarioAdvanced
Clinical prompt
“A 9-year-old boy presents with progressive left knee valgus. Two years ago he sustained a Salter-Harris type IV fracture of the lateral distal femur treated with open reduction and internal fixation. He now has a 12-degree valgus deformity and a 1.5 cm limb-length discrepancy. Bone age is 8.5 years. How do you manage him?”
Practical approach
This boy has a classic presentation of partial physeal arrest following a Salter-Harris type IV fracture of the distal femur — the lateral femoral physis has partially closed, producing progressive valgus and a developing limb-length discrepancy.
**First step: confirm the diagnosis and map the bar.** I would obtain a CT arthrogram or MRI of the left distal femur to map the size, location, and extent of the physeal bar. I need to know what proportion of the physis is involved and whether the bar is peripheral (favourable) or central (less favourable).
**Assess growth remaining.** Bone age is 8.5 years in a boy — this means he has approximately 5 to 6 more years of distal femoral growth remaining (distal femur contributes roughly 9 mm/year). He has well over 2 years and well over 2 cm of growth remaining. This strongly favours bar resection over completion epiphysiodesis.
**Decision: bar resection.** If the CT arthrogram shows the bar is less than 50 percent of the physis (which is likely given the moderate 12-degree valgus), I would proceed with physeal bar resection with autologous fat graft interposition through a lateral metaphyseal approach.
**Concurrent osteotomy.** The 12-degree valgus is an established deformity. At his age, even with successful growth resumption, correction through growth alone will take many years. I would discuss a concurrent lateral closing-wedge distal femoral osteotomy at the time of bar resection to correct the valgus acutely, followed by ongoing growth correction of any residual deformity through the re-opened physis.
**Post-operative plan.** Plaster immobilisation for 6 weeks. Serial radiographs every 3 months to monitor growth resumption and osteotomy healing. MRI at 12 months to check for bar recurrence and interposition position. Predict final LLD using Moseley straight-line chart — if the predicted discrepancy exceeds acceptable limits, plan contralateral distal femoral epiphysiodesis at the appropriate time.
**Counselling.** I would explain to the family that bar resection has a recurrence risk of approximately 10 to 30 percent, that we are choosing this over completion epiphysiodesis because he has substantial growth remaining, and that the goal is to restore growth and prevent worsening deformity. I would also discuss the osteotomy and its additional risks (non-union, hardware irritation, over- or under-correction).
Viva scenarioAdvanced
Clinical prompt
“A 7-year-old girl has been referred with a progressive varus deformity of the right proximal tibia. She had osteomyelitis of the proximal tibia at age 4, treated with antibiotics and surgical drainage. Her bone age is 6.5 years. A CT arthrogram shows a central physeal bar occupying approximately 40 percent of the proximal tibial physis. How would you manage this?”
Practical approach
This girl has partial physeal arrest of the proximal tibia secondary to previous osteomyelitis — a central bar occupying 40 percent of the physis. The bar is central, which is a more challenging surgical problem than a peripheral bar, but it is still less than 50 percent, and she is young with substantial growth remaining.
**Confirm growth remaining.** Bone age is 6.5 years in a girl. The proximal tibia contributes approximately 6 mm/year of growth and closes around age 12 in girls. She has approximately 5 to 6 years and 3 to 4 cm of growth remaining — well above the 2-year and 2-cm threshold. Resection is viable.
**The central location is the key surgical challenge.** Unlike a peripheral bar, this requires an epiphyseal approach — drilling through the epiphysis to reach the central bar. I would plan the drill trajectory carefully on the CT arthrogram, choosing an entry point that minimises articular cartilage damage, ideally through a non-weight-bearing area of the proximal tibial articular surface.
**Surgical plan.** Under general anaesthesia and image intensifier guidance: create a small drill hole through the proximal tibial epiphysis aimed at the central bar; advance a guidewire into the bar under fluoroscopic control; ream over the guidewire to create an access channel; excise the bar with curettes passed through the channel; verify completeness with intraoperative arthrogram (dye flowing freely across the physis); pack the cavity with autologous fat graft supplemented by cranioplast for radiographic verification of interposition position.
**Why cranioplast in addition to fat.** Central bars have higher recurrence rates, and fat graft resorption contributes to recurrence. Cranioplast is radiopaque, permanent, and does not resorb — it allows me to confirm on post-operative imaging that the interposition remains in position. This is especially valuable for central bar resections.
**Concurrent osteotomy.** The 40-percent central bar has likely produced a significant varus deformity by now. I would measure the mechanical axis deviation and plan a medial opening-wedge proximal tibial osteotomy (or lateral closing-wedge) at the same sitting if the deformity is sufficient to warrant acute correction.
**Post-operative and long-term.** Immobilise in an above-knee cast for 6 weeks. Serial radiographs every 3 months. MRI at 6 and 12 months to check for bar recurrence and interposition integrity. Monitor growth resumption and deformity correction. If recurrence occurs, the options are revision resection (if growth remains sufficient) or completion epiphysiodesis with contralateral epiphysiodesis.
Viva scenarioStandard
Clinical prompt
“A 13-year-old boy has a 15-degree valgus deformity of the left distal femur with a 2.5 cm limb-length discrepancy. CT arthrogram shows a physeal bar occupying approximately 45 percent of the distal femoral physis. His bone age is 13 years. How would you counsel him and his family?”
Practical approach
This is a borderline case that tests the decision between bar resection and completion epiphysiodesis — and the answer depends on careful growth prediction.
**Assess the bar.** At 45 percent, the bar is just below the 50-percent threshold for resection. It is on the larger side, which increases recurrence risk, but it is still technically within the resectable range.
**Assess growth remaining — this is the critical factor.** Bone age is 13 in a boy. The distal femur contributes roughly 9 mm/year and closes around age 16 in boys. He has approximately 3 years and 2.5 to 3 cm of distal femoral growth remaining. This meets the 2-year and 2-cm threshold, but only just, especially when the bar is already at 45 percent.
**Growth prediction.** Using a Moseley straight-line chart, I would plot his current deformity, LLD, and predicted growth to estimate the mechanical axis deviation and LLD at skeletal maturity with and without intervention. If successful resection resumes full growth on the affected side, the deformity could partially self-correct and the LLD could stabilise or improve. But with a 45-percent bar and only 3 years of growth remaining, the correction through growth alone is limited — and recurrence risk is high.
**My recommendation.** I would counsel the family that bar resection is possible but carries a meaningful recurrence risk given the bar size (45 percent) and that the time window for growth correction is relatively short (approximately 3 years). I would present two options:
Option 1: Bar resection with concurrent corrective osteotomy (acute valgus correction) and autologous fat graft with cranioplast interposition. This offers the possibility of further growth correction but carries a 20 to 30 percent recurrence risk and requires close long-term follow-up.
Option 2: Completion epiphysiodesis of the lateral distal femoral physis (or the entire physis if the bar is already extensive) combined with a distal femoral medial opening-wedge osteotomy for acute correction, and contralateral distal femoral epiphysiodesis timed to manage the LLD. This is more predictable but sacrifices any further growth correction from the affected physis.
For most families in this scenario, given the borderline bar size and limited growth window, I would lean towards completion epiphysiodesis with osteotomy — the risk-reward ratio for resection is less favourable than in a younger child with a smaller bar.
Exam day cheat sheet
Physeal Bar Resection — Exam Day Summary
References
Evidence
Partial growth plate arrest and its treatment
Level IV
Peterson HA
Clinical implication: The Peterson classification guides surgical planning and prognostication: peripheral bars have the best outcomes, central bars the most challenging.
Partial physeal growth arrest: treatment by bridge resection and fat interposition
Level IV
Williamson RV, Staheli LT
Clinical implication: CT arthrography is essential for pre-operative planning; accurate bar mapping improves surgical outcomes and guides approach selection.
Excision of Physeal Bars of the Distal Femur, Proximal and Distal Tibia Followed to Maturity
Level IV
Yuan BJ, Stans AA, Larson DR
Clinical implication: Modern long-term follow-up data supports bar resection in carefully selected patients; bar size and remaining growth remain the key prognostic factors.
Secondary tethers after physeal bar resection: a common source of failure?
Level IV
Hasler CC, Foster BK
Clinical implication: Recurrent deformity after bar resection may be due to a secondary tether rather than regrowth of the original bar; re-imaging with CT or MRI is essential before planning revision surgery.