Limb Lengthening with a Submuscular Locking Plate

Journal of Bone and Joint SurgeryEssential Surgical Techniques

April 2014,vol3Chang-Wug Oh et al

Kyungpook N U Hospital, Republic of Korea

Level of evidence Ib

PRESENTER : Dr SAUMYA AGARWAL

Junior resident Dept of Orthopaedics J.N. Medical College and Dr. Prabhakar Kore Hospital and MRC, Belgaum

INTRODUCTION

Limb lengthening with a submuscular locking plate is a good alternative for patients especially children, in whom lengthening over an intramedullary nail would be difficult.

• Distraction osteogenesis with an external fixator is widely used to treat limb length discrepancy

• But prolonged external fixation can cause many complications such as

pin track infection joint instability and stiffness refracture after fixator removal.

Lengthening over an intramedullary nail

• shortens duration of external fixation• protects distracted bone during

consolidation phase • reduces rate of complications when

compared external fixator alone.• regain movement more quickly • return to activities of daily life in less

time.

• It is difficult to use an intramedullary nail when :

patient has a narrow medullary canal bone deformity open physes joint contracture may lead to femoral head osteonecrosis in

children.

• Submuscular fixation with a locking plate is a recent advance in fracture treatment

• Has advantage of providing angular stability

and preserving the periosteal and endosteal

blood supply.

• Limb Lengthening with a Submuscular Locking Plate is performed with

4 steps 2 operations

STEP 1 : External fixation for lengthening with . submuscular plating

Submuscular plating external fixation with corticotomy

A. Submuscular Plating

Tibial lengthening:• Supine position

• 3-4 cm incision in area of Gerdy’s tubercle in proximal tibia

• Iliotibial band and tibialis anterior fascia is incised and muscle is elevated

• a submuscular tunnel is made along lateral surface of tibia with periosteum elevator

• a 3 hole plate is inserted into submuscular tunnel extraperiosteally

• 3 locking screws are inserted in proximal portion of plate

Femoral lengthening :

• Lateral / supine position

• 3-4 cm incision along lateral aspect of greater trochanter

• Iliotibial tract and vastus lateralis fascia incised

• vastus lateralis muscle dissected

• Submuscular tunnel made along lateral surface of femur

• An anterior bow 4.5 mm straight locking compression plate is used

• Plate inserted along lateral surface of femur through submuscular tunnel

• 3 or 4 locking screws are used to fix plate to proximal segment.

• In some cases , use of a flexible intramedullary nail helps to stabilize the distal segment and prevent angular deformity while lengthening is taking place.

B. External fixation with corticotomy

• External fixator with lengthening frame is used.• For tibia, monolateral frame is fixed to

medial side of each segment using 3 half pins.• For femur, 3 half pins are fixed to lateral

side of proximal and distal segment of plate.

• Cross contamination should be avoided.• Half pins and wires used for external

fixation should not touch plate or screws.• A fibular osteotomy is done and with

the help of 1 or 2 , 3.5mm cortical screw the distal tibiofibular joint is secured.

• Now percutaneous corticotomy is performed

• 1 cm incision is taken about 1 cm below the distal screw of the proximal segment.

• Multiple drill holes are made and complete corticotomy is done.

• Corticotomy can be done either before palting or after plating.

Step 2 : Lengthening

• Distraction is started after 7 to 10 days• At the rate of 1mm per day• 4 times a day• Partial weight bearing and physiotherapy

is started to maintain movement of adjacent joints• Radiograph is taken weekly to monitor

progress.

Step 3: Locking of the distal segment and removal of the external fixator

• Whole extremity together wih external fixator drapped.

• Under C-Arm, empty plate holes of the distal segment are marked for planned screw fixation.

• A stab skin incision is taken and soft tissue dissection is done.

• At least 3 bicortical screws are placed percutaneously through plate into distal segment.

• Now wound is closed and external fixator is removed.

• Wound made by external fixator are then cleaned and dressed.

4. Postoperative care

• Mobilization and partial weight bearing started immediately after fixator is removed.

• A radiograph is taken every 4 to 8 weeks until the distraction callus is fully consolidated.

• Patient is allowed full weight bearing walk with crutches when signs of osseous consolidation are observed in atleast 3 cortices.

• Slowly wean the patient off the crutches.

RESULTS

• 10 Patients were operated for limb lengthening

• Mean amount of legthening 4cm• External fixator was in place for 61 days• mean healing index was 48.1 days/cm• Target length was achieved in all the

patients.

• Total 9 complications and all resolved before last follow up visit.• 4 superficial pin track infection resolved

with oral antibiotics.• 4 patients had joint stiffness resolved with

physiotherapy.• One patient sustained a tibial fracture for

which he got operated.

• All 10 patients were walking with full, unassisted weight bearing excellent joint motion solid union at lengthening site normal limb alignment

INDICATIONS

• Skeletally immature patients because of open physis narrow medullary canal osteonecrosis of the femoral head

• Nail insertion is difficult: Presence of osseous deformity Joint contracture Previous arthroplasty

CONTRAINDICATIONS

• Plate is inherently inferior to intramedullary nail in terms of bending and axial stiffness.

PITFALLS and CHALLENGES

• Half pins or wires should not contact the plate or screws to avoid cross contamination.

• To provide sufficient stability longer plate should be choosen.

• Use of protection device like brace is recommended until sufficient consolidation is achieved.

• In skeletally immature patients screws should not intrude the epiphyseal plate.

CLINICAL COMMENTS

• Lengthening with a submuscular locking plate did not disturb the regeneration of distraction callus.

• Healing indices achieved were similar to those with conventional lengthening without plate.

• This techniques permit earlier removal of the external fixator.

THIS STUDY ALSO SAY’s:

• The use of plate of sufficient length, fixed with 3 or more bicortical screws per segment provides adequate stability.

• Since plate is inherently inferior to intramedullary nail in terms of bending and axial stiffness, authors prefer to use intramedullary nail when it can be inserted without undue difficulty.