import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Exits lateral intermuscular septum 10cm proximal to lateral epicondyle, wraps around radial neck. **Protection**: Stay subperiosteal on lateral humerus, avoid dissection distal to lateral epicondyle. **Location**: Posterior to medial epicondyle in cubital tunnel. **Protection**: For posterior approach or medial hinge completion, identify and protect with vessel loop if necessary. **Location**: Continuation of musculocutaneous nerve, lateral to biceps tendon at elbow crease. **Protection**: Protect during anterior dissection; injury causes lateral forearm numbness. **Location**: Anteromedial to distal humerus in antecubital fossa. **Protection**: Keep anterior periosteum intact as barrier. Avoid anterior dissection or penetrating anterior cortex with osteotome. **Location**: 1-2cm distal to osteotomy site in skeletally immature patients. **Protection**: Maintain osteotomy at supracondylar level, proximal to olecranon fossa. **Patient Position**: Supine with arm across chest or on arm board, upper arm tourniquet **Surgical Approach**: Lateral approach (Kocher interval) or posterior approach **Incision**: 8-10cm lateral incision centered over lateral epicondyle or posterior midline over distal humerus ### Understanding Cubitus Varus Deformity **Etiology:** - Supracondylar fracture malunion (most common - 30% if inadequately treated) - Lateral condyle nonunion with overgrowth - Physeal arrest - Congenital **Deformity Components (3D):** 1. **Coronal:** Varus angulation (loss of carrying angle) 2. **Sagittal:** Extension or hyperextension (loss of anterior humeral line) 3. **Axial:** Internal rotation of distal fragment **Clinical Assessment:** - Carrying angle measured with elbow extended, forearm supinated - Normal: 5-15° valgus (greater in females) - Cubitus varus: 0° or negative carrying angle - Compare to contralateral side **Radiographic Parameters:** - **Baumann angle**: Normal 70-75° (decreased in varus) - **Humeral-capitellar angle**: Normal 5-15° valgus - **Anterior humeral line**: Should pass through middle third of capitellum ### Osteotomy Options for Correction | Type | Description | Advantages | Disadvantages | |------|-------------|------------|---------------| | **Lateral Closing Wedge** | Remove lateral wedge, close gap | Simple, stable, most common | Lateral prominence, step-off | | **Dome Osteotomy** | Semicircular cut | No shortening, adjustable | Technically demanding | | **French (Step-Cut)** | Step-cut osteotomy | Large surface contact, stable | Complex cuts | | **Medial Opening Wedge** | Open medial side with graft | No lateral prominence | Requires graft, unstable | | **3D Printed Template** | Custom-guided cuts | Precise correction | Expensive, planning time | **Lateral Closing Wedge (Standard):** - Most commonly performed - Wedge base laterally, apex medially - Wedge angle = 2 × varus angle - Creates lateral condylar prominence (cosmetic issue) - May include rotational correction ### Preoperative Planning Steps **Radiographic Analysis:** 1. AP and lateral radiographs of both elbows 2. Measure carrying angle clinically and radiographically 3. Assess sagittal plane (extension/flexion) 4. Assess rotation clinically **Calculating Correction:** - Target: Match contralateral normal carrying angle - Wedge angle = Current varus + Target valgus - Example: 15° varus + 10° valgus target = 25° wedge **Template Planning:** - Draw osteotomy on tracing paper over radiograph - Wedge apex at medial cortex - Base width = 2 × (sin of wedge angle) × bone diameter - Mark K-wire trajectory for fixation **3D Considerations:** - If internal rotation present, add rotational correction - If hyperextension present, add flexion at osteotomy - Consider CT for complex multiplanar deformity ### Fixation Methods After Osteotomy **Crossed K-wires:** - 2-3 K-wires (1.6-2.0mm) - Medial and lateral entry points - Cross at osteotomy site - Leave wires percutaneous for removal at 4-6 weeks - Advantages: Simple, pediatric-friendly - Disadvantages: Requires cast, wire migration, pin tract infection **Plate Fixation:** - Lateral column plate (LCP or recon plate) - 3 screws proximal, 3 screws distal to osteotomy - Advantages: Stable, early mobilization possible - Disadvantages: More dissection, prominent hardware, second surgery for removal **External Fixation:** - Rarely used - Reserved for soft tissue concerns or staged correction **Preferred Approach:** - Paediatric patients: Crossed K-wires + cast (most common) - Adolescents/adults: Plate fixation for early mobilization ### Posterolateral Rotatory Instability **Why PLRI Occurs with Cubitus Varus:** - Varus alignment shifts forces to lateral column - Increased stress on lateral collateral ligament complex - Progressive lateral ligament insufficiency - Can develop years after initial injury **Clinical Features:** - Lateral elbow pain with pushing up from chair - Clicking or snapping sensation - Positive lateral pivot shift apprehension **Management Implications:** - PLRI is an indication for varus correction - Correcting alignment reduces lateral column loading - May require simultaneous LCL reconstruction - O'Driscoll procedure if ligament attenuation severe **Prevention:** - Adequate initial fracture treatment - Consider early correction before PLRI develops - Long-term follow-up for varus malunion ### Step 1: Preoperative planning and template preparation Preoperative planning and template preparation: Measure carrying angle on both sides clinically (elbow extended, forearm supinated). Review AP and lateral radiographs of both elbows. Measure varus deformity angle (difference from normal contralateral side). Calculate wedge angle: varus angle + desired valgus (typically 10°). Template osteotomy on radiograph - mark wedge base laterally, apex medially. Calculate wedge base width: 2 × sin(wedge angle) × bone diameter at osteotomy level. Assess sagittal plane for extension component. Assess rotation clinically for internal rotation. Prepare K-wires (1.6-2.0mm), oscillating saw, and fixation implants. **Technical Tip**: EXAM KEY: Use contralateral normal elbow as the target. If 15° varus deformity and target is 10° valgus, wedge angle = 25°. Template precisely on paper before surgery. - Under-planning leads to under-correction or over-correction. Measure angles on standardized radiographs with elbow in true AP position. Missing rotational component is common error - assess clinically by comparing shoulder rotation with elbow flexed. ### Step 2: Patient positioning, tourniquet application, and preparation Patient positioning, tourniquet application, and preparation: Position supine on radiolucent table. Arm on arm board or hand table with shoulder abducted 90°, elbow accessible for lateral approach. Apply upper arm tourniquet (250-300mmHg for child). Position C-arm from opposite side for AP and lateral views. Check fluoroscopy access before prepping - ensure true AP and lateral obtainable. Prep and drape entire arm from shoulder to fingertips. Mark lateral epicondyle, olecranon, and planned 8-10cm lateral incision. **Technical Tip**: EXAM KEY: Arm position must allow both AP and lateral fluoroscopy. Check before draping - reposition if views inadequate. - Tourniquet on too long (limit to 90 minutes). Fluoroscopy access inadequate once draped - check views before prepping. Sterile prep must include area for K-wire placement medially and laterally. ### Step 3: Lateral approach to distal humerus Lateral approach to distal humerus: Make 8-10cm straight lateral incision centered over lateral supracondylar ridge, starting proximal to lateral epicondyle. Incise skin and subcutaneous tissue. Identify lateral intermuscular septum. Develop plane between triceps posteriorly and brachioradialis/brachialis anteriorly (modified Kocher interval). Subperiosteal elevation on lateral and posterior humerus at supracondylar level (1-2cm proximal to olecranon fossa). Protect soft tissues anteriorly (brachial artery and median nerve) by maintaining intact anterior periosteum. Identify and protect radial nerve proximally if dissection extends greater than 8cm proximal to lateral epicondyle. **Technical Tip**: EXAM KEY: The lateral intermuscular septum is the key structure - radial nerve pierces it 10cm proximal to epicondyle. Stay on bone subperiosteally at osteotomy site. - Radial nerve injury (exits septum 10cm proximal) - limit proximal dissection. Brachial artery and median nerve anterior - keep anterior periosteum intact. Do not dissect distal to epicondyle (physis and PIN at risk). ### Step 4: Mark osteotomy site and place guide K-wires Mark osteotomy site and place guide K-wires: Identify osteotomy site at supracondylar level (1-2cm proximal to olecranon fossa, proximal to growth plates in children). Place first guide K-wire perpendicular to humeral shaft from lateral cortex - this marks the distal cut. Place second K-wire at the calculated wedge angle proximally (this marks the proximal cut). The angle between wires equals the planned correction. Confirm position with AP and lateral fluoroscopy - wires should be at supracondylar level, proximal to olecranon fossa and capitellum. If rotation correction needed, mark rotational position on cortex with osteotome scratches. **Technical Tip**: EXAM KEY: Guide K-wires are critical for precise correction. The angle between them is the correction angle. Check with goniometer if unsure. - Osteotomy too distal - violates joint or olecranon fossa. Osteotomy too proximal - cosmetic deformity at different level. K-wires not in same plane - creates unintended rotational or sagittal malalignment. ### Step 5: Perform lateral closing wedge osteotomy Perform lateral closing wedge osteotomy: Using oscillating saw, make first (distal) cut perpendicular to humeral shaft along the distal K-wire. Keep anterior periosteum intact (protects neurovascular bundle). Extend cut to but not through medial cortex - leave medial hinge intact. Make second (proximal) cut along proximal K-wire, converging toward medial cortex. Remove the lateral-based wedge of bone. Save bone wedge as possible graft. The wedge should have its base laterally and apex at the intact medial hinge. Copiously irrigate to remove bone debris. **Technical Tip**: EXAM KEY: Medial hinge is critical - provides stability, prevents translation, and acts as a pivot point for correction. If medial cortex cuts through, osteotomy becomes unstable. - Saw generating heat - irrigate during cutting to prevent thermal necrosis. Anterior cortex penetration - exposes neurovascular bundle to saw blade. Complete medial cortex cut - loses hinge stability. Saw blade bending in bone - can break. ### Step 6: Close osteotomy and correct deformity Close osteotomy and correct deformity: Gently close the osteotomy by adducting the forearm (varus stress to distal fragment). The medial hinge should act as a pivot point, allowing the lateral gap to close. Apply gradual pressure until lateral cortices oppose. Check alignment clinically - elbow extended, forearm supinated - assess carrying angle. Compare to contralateral side intraoperatively. If rotation correction required, rotate distal fragment externally before closing osteotomy. If hyperextension correction needed, flex distal fragment slightly before closing. Confirm correction with fluoroscopy - Baumann angle should match contralateral side. **Technical Tip**: EXAM KEY: Check carrying angle with elbow fully extended and forearm supinated - this is the clinical measure that matters. Intraoperative comparison to contralateral side is essential. - Over-correction to valgus (worse than leaving varus). Medial hinge cracks - creates translation and instability. Not correcting rotation if present - leaves internal rotation deformity. Not checking sagittal plane - may create hyperextension. ### Step 7: Temporary fixation with K-wires and fluoroscopic confirmation Temporary fixation with K-wires and fluoroscopic confirmation: Maintain reduction manually. Insert first K-wire (1.6-2.0mm) from lateral epicondyle, directing proximally and medially across osteotomy. Insert second K-wire from medial epicondyle, directing proximally and laterally across osteotomy (identify and protect ulnar nerve by palpation - wire anterior to nerve). Wires should cross at osteotomy site. Consider third lateral wire for additional stability. Confirm position on AP and lateral fluoroscopy. Check Baumann angle (should match contralateral), carrying angle clinically, and osteotomy apposition. **Technical Tip**: EXAM KEY: Medial wire at risk for ulnar nerve - palpate nerve, flex elbow to move nerve posteriorly, insert wire with elbow flexed then extend for fluoroscopy. Start wire anterior to medial epicondyle. - Ulnar nerve injury from medial K-wire (most common technical error). Wires not crossing at osteotomy - reduces construct stability. Pins too superficial - not engaging proximal fragment cortex. Loss of reduction during wire insertion. ### Step 8: Definitive fixation - K-wires or plate Definitive fixation: For K-wire fixation (most common in children): Bend and cut wires percutaneously 1cm from skin. Apply dressing and above-elbow backslab at 90° flexion. K-wires removed at 4-6 weeks. For plate fixation (adolescents/adults): Apply lateral column plate (3.5mm LCP or recon plate). Minimum 3 screws proximal, 3 screws distal to osteotomy. Contour plate to match lateral humeral anatomy. Unicortical or carefully placed bicortical screws to avoid anterior neurovascular structures. Check ROM intraoperatively - should be near-full flexion-extension. **Technical Tip**: EXAM KEY: K-wires for children (simple, effective, low profile). Plates for adolescents/adults (allows early mobilization). Plate requires second surgery for removal but permits earlier ROM. - Anterior cortex screw penetration - risks brachial artery and median nerve. Plate prominence - may require removal in thin patients. Over-contouring plate - can alter correction achieved. ### Step 9: Wound closure and immobilization Wound closure and immobilization: Release tourniquet. Achieve hemostasis with bipolar cautery. Irrigate wound thoroughly with saline. Close periosteum if possible with 2-0 absorbable suture. Close deep fascia and subcutaneous layer with 3-0 absorbable sutures. Close skin with 4-0 subcuticular absorbable suture or nylon. Apply sterile dressings. Apply well-padded above-elbow posterior splint or cast at 90° elbow flexion. Ensure adequate padding over K-wire sites if percutaneous. Check distal pulses, capillary refill, and finger movement before leaving OR. **Technical Tip**: EXAM KEY: Position elbow at 90° flexion in splint - this is the functional position and protects the osteotomy. Check neurovascular status after cast application. - Tight cast causing compartment syndrome (especially in children). Hematoma if hemostasis inadequate. K-wire sites insufficiently padded - skin breakdown. Loss of reduction if cast too loose. ### Step 10: Final fluoroscopic documentation and postoperative planning Final fluoroscopic documentation and postoperative planning: Obtain final AP and lateral fluoroscopic images in cast/splint. Document Baumann angle (should match contralateral normal). Confirm K-wire or plate position adequate. Compare carrying angle to preoperative measurement - document correction achieved. Plan postoperative care: K-wires out at 4-6 weeks, cast for 4-6 weeks total, ROM exercises starting at 6 weeks. Document for operative report: wedge angle, degree of correction achieved, fixation used, neurovascular status at end of case. **Technical Tip**: EXAM KEY: Documentation of correction angle and Baumann angle is important for medicolegal purposes and follow-up comparison. - Inadequate documentation - always record preoperative and postoperative angles. Failure to check neurovascular status in final cast - compartment syndrome can develop early. Not arranging appropriate follow-up - pin site care and wire removal timing critical. Above elbow posterior splint at 90 degrees for 5-7 days. Convert to cast once swelling subsided. Immobilization 4-6 weeks (plate) or 6-8 weeks (K-wires). K-wire removal at 6-8 weeks. Begin active-assisted ROM after immobilization - gentle flexion/extension, avoid varus-valgus stress. Physiotherapy for ROM and strengthening at 8-10 weeks. Radiographs at 2, 6, 12 weeks. Plate removal at 6-12 months after union. Full activity at 3-4 months once union solid and ROM restored. 1. **Voss FR, Kasser JR, Trepman E, et al.** Uniplanar supracondylar humeral osteotomy with preset Kirschner wires for posttraumatic cubitus varus. *J Pediatr Orthop* 1994;14:471-478. 2. **Oppenheim WL, Clader TJ, Smith C, Bayer M.** Supracondylar humeral osteotomy for traumatic childhood cubitus varus deformity. *Clin Orthop Relat Res* 1984;188:34-39. 3. **Kim HT, Lee JS, Yoo CI.** Management of cubitus varus and valgus. *J Bone Joint Surg Am* 2005;87:771-780. 4. **O'Driscoll SW, Spinner RJ, McKee MD, et al.** Tardy posterolateral rotatory instability of the elbow due to cubitus varus. *J Bone Joint Surg Am* 2001;83:1358-1369. 5. **Bellemore MC, Barrett IR, Middleton RW, et al.** Supracondylar osteotomy of the humerus for correction of cubitus varus. *J Bone Joint Surg Br* 1984;66:566-572. 6. **Wong HK, Lee EH, Balasubramaniam P.** The lateral condylar prominence - a complication of supracondylar osteotomy for cubitus varus. *J Bone Joint Surg Br* 1990;72:859-861. 7. **Takeyasu Y, Murase T, Miyake J, et al.** Three-dimensional analysis of cubitus varus deformity after supracondylar fractures of the humerus. *J Shoulder Elbow Surg* 2011;20:440-448. 8. **DeRosa GP, Graziano GP.** A new osteotomy for cubitus varus. *Clin Orthop Relat Res* 1988;236:160-165. 9. **Morrey BF.** Post-traumatic stiffness: Distraction arthroplasty. In: Morrey BF, ed. *The Elbow and Its Disorders*. 4th ed. Philadelphia: Saunders; 2009:1039-1062. 10. **Ippolito E, Moneta MR, D'Arrigo C.** Post-traumatic cubitus varus. Long-term follow-up of corrective supracondylar humeral osteotomy in children. *J Bone Joint Surg Am* 1990;72:757-765.

Cubitus Varus Correction (Supracondylar Osteotomy)

Cubitus Varus Correction (Supracondylar Osteotomy)