Cubitus Varus Osteotomy

Peter M. Waters

Operative Indications

Malunion of distal humerus supracondylar fracture, usually Baumann angle >90° (Figure 14.1)

Surgical Technical Options

Closing wedge osteotomy (Figure 14.2)
Dome osteotomy (Figure 14.3)
Step cut osteotomy
Internal fixation with smooth wires or plates and screws
External fixation
Growth modulation NOT an option (Figure 14.4)

Closing Wedge Step Osteotomy (Figure 14.5)

Equipment

Fluoroscopy
Fluoroscopic arm and hand table
Smooth K-wires
Oscillating saw
Power drill
Osteotomes
Tourniquet

Figure 14-1 ▪ Clinical photograph of cubitus varus preoperatively. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 14-2 ▪ Illustration of surgical correction. A, Cubitus varus with illustration of oblique closing wedge osteotomy. B, After wedge removal, osteotomy correction and pin fixation. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 14-3 ▪ Illustration of Dome osteotomy correction with (A) precorrection and (B) postcorrection. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 14-4 ▪ A, AP and (B) lateral radiographic views of unsuccessful growth modulation to correct cubitus varus performed at outside institution. Correction was achieved with hardware removal and osteotomy. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 14-5 ▪ Preoperative photographs of cubitus varus. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Positioning

Supine with arm extended on fluoroscopic table

Surgical Approach

Straight lateral approach to distal humerus
- Extend from distal lateral condylar prominence proximally to diaphysis
- Be aware of radial nerve crossing proximally
Subperiosteal anterior and posterior exposure
Anteriorly stay subperiosteally to protect median nerve and brachial artery
- This is especially important if there is marked extension malunion in which neurovascular bundle (NVB) can be anteromedial to exostosis (median nerve has been iatrogenically injured in corrective osteotomy)
Posteriorly expose olecranon fossa completely to be certain osteotomy cuts stay above fossa later in case
Medially stay subperiosteally to protect ulnar nerve throughout case
Protect radial nerve anteriolaterally at the proximal edge of incision. Large Hohmann retractors are placed anteriorly all the way across to anteriomedial distal humerus to expose malunion and protect anteriomedial brachial artery and median nerve. The NVB can get stuck as it drapes over malunion, and this protective subperiosteal elevation is very important for safe surgical care
This retractor enables full visualization of anterior cortex during pin placement and osteotomy cuts to prevent error. Similar large Hohmann retractor is placed posteriorly all the way across to posteriomedial distal humerus. This protects ulnar nerve throughout operation
Enables full visualization of olecranon fossa during pin placement and osteotomy cuts to prevent error